Electron Microscopy
24 articles
BUTVAR B-98 Support Film
BUTVAR B-98 support films are mechanically stable, electron-transparent, and have minimum intrinsic structure. Their hydrophilic nature facilitates the spreading of the sections allowing even staining on the surface. This film can resist an intense electron beam during focusing and photography at high magnifications, or with the beam at cross-over. The mechanical stability is appreciated when mounting freeze-fractured replicas or serial sections, especially when slotted grids are used. Procedure Stock solution - 0.25% BUTVAR (w/v) in chloroform: Due to limited solubility the solution is unstable and sensitive to humidity. Heat (in a water bath) to 50°C with continual stirring and cool to 40°C - 42°C just before coating grids. This heating procedure is extremely important to insure complete solubility of the BUTVAR and to obtain a good surface uniformity of the film free from irregularities, holes or wrinkles. Use a pre-cleaned, 1x3 microscope slide (washed in 70% alcohol and flame dried). Dip slides into stock solution and drain them in a vertical, inclined position in a dust free place (drawer or cabinet) on a paper towel or any absorbent material. The upwards facing side is the thinnest (40nm). Dried slides are scored on the corners, and the film released by flotation into a staining dish filled with distilled water. Grids are arranged in 2 or 3 rows. The film is retrieved with parafilm (2x4 inch) by gently touching one edge of the resin film, lowering into complete contact, then lifting up with a fast motion. Coated grids can be used immediately and may be stored for several years. Films for slotted grids are prepared in the same way. If grids are difficult to remove, the film may be scored around the periphery with the tip of a forcep, or the concentration of the stock solution can be reduced to 0.20%. The stock solution is usable indefinitely when stored in an amber bottle, well capped, at room temperature.
C-flat™ Holey Carbon Films & Grids for Cryo-TEM
Overview C-flat™ is an ultra-flat, holey carbon-coated TEM support grid for transmission electron microscopy (TEM). Unlike competing holey carbon films, C-flat™ is manufactured without plastics, so it is clean upon arrival and the user has no residue to contend with. C-flat™ leads to better data sets Made with patent pending technology, C-flat™ provides an ultra-flat surface that results in better particle dispersion and more uniform ice thickness. Patterning is done using deep-UV projection lithography, ensuring the most accurate and consistent hole shapes and sizes down to submicron features. The precise methods by which C-flat™ is manufactured eliminate artefacts such as excess carbon and edges around holes. C-flat™ is affordable C-flat™ is available in 25, 50, and 100 packs at a per-grid price less than competing products. Applications C-flat™ holey carbon grids provide the ideal specimen support to achieve high resolution data in cryo-TEM making them an ideal choice for single particle analysis, cryo electron tomography and automated TEM analysis. Cryo-electron tomography (cryoET) and Single Particle Analysis ( SPA ) Numerous researchers have reported that the ultra-flat surface of C-flat™ leads to even ice thickness and uniform particle distribution within the hole areas. This optimal particle distribution results in superior data being collected as compared with other holey support films. 2µm hole sizes are standard but custom hole sizes are available so C-flat™ can accommodate the common magnifications used for quantitative TEM analysis. Automated TEM C-flat™ provides a regular array of analysis sites compatible with automated data collection software such as Leginon. This compatibility, in combination with the more uniform ice thickness and particle distribution reported by numerous researchers, results in more high-quality target sites per grid. Publications using C-flat™: Does contamination buildup limit through put for automated cryoEM? , Journal of Structural Biology, Volume 154, Issue 3, June 2006, Pages 303-311 Anchi Cheng, Denis Fellmann, James Pulokas, Clinton S. Potter and Bridget Carragher Automated cryoEM data acquisition and analysis of 284 742 particles of GroEL , Journal of Structural Biology, In Press, Uncorrected Proof, Available online 22 May 2006, Scott M. Stagg, Gabriel C. Lander, James Pulokas, Denis Fellmann, Anchi Cheng, Joel D. Quispe, Satya P. Mallick, Radomir M. Avila, Bridget Carragher and Clinton S. Potter Product Line C-flat™ is a holey carbon film supported by a standard TEM grid. C-flat™ products are fully specified by 4 parameters: the hole diameter and pitch of the holey carbon film and the material type and mesh size of the TEM grid. The following image illustrates these parameters: Standard Products The breadth of applications in cryoTEM necessitate a wide range of holey carbon film patterns. And now, with the recent expansion of the product line, a C-flat™ holey carbon film is available for almost any application. Whether 600nm holes are needed for very high magnifications with ultra-high resolution cameras or large open areas are needed for larger specimens, C-flat™ is the perfect holey carbon grid. C-flat™ is immediately available in several standard array patterns including hole diameters/hole spacings of 0.6/2, 1/1, 1/2, 1/4, 1.2/1.3, 2/1, 2/2, 2/4, 4/2, and a multihole pattern. C-flat™ is supported by your choice of a 200 mesh or 400 mesh copper TEM grid and sold in quantities of 25, 50, or 100.
Carbon Grating Replicas
Calculating the Magnification Calculate the electron microscope magnification using the diffraction grating replica pattern as follows; measure (in millimetres) between the limiting lines of as many squares of the replica pattern as possible and apply the following formula: Distance in mm between limiting lines x 2,160 Magnification = Number of spaces between limiting lines Note: Limiting lines are chosen arbitrarily by the viewer. Statistical significance increases with the distance between the 2 limiting lines due to the increased size of the sample; i.e., the more "lines or spaces" included in the measurement, the more accurate the calibration. Care of Grating Replica Specimens: When not in use, the replica should be kept in a dust‐free atmosphere (as the same vial in which it is supplied). The replica surface can be damaged if it is touched with any hard object. NEVER TRY TO CLEAN IT. Care should be taken with the TEM specimen to avoid bending the grid, which can cause cracking of the replica. When viewing a replica specimen in the TEM always begin at low magnification, with one square of the supporting copper grid filling the EM screen, slowly increase the illumination to near maximum intensity (but not to cross‐over) then reduce the level of the illumination and go to the desired magnification. Repeat this procedure every time a new area of the replica is to be viewed. Low Magnification Grating Replica Gratings are germanium shadowed carbon replicas made from a 15,240 line per inch diffraction grating. The actual grating spacing is 1667 millimicrons. They are supplied mounted on grids as required by the customer. For accurate work, the microscope should be calibrated at each high voltage separately. For each magnification run, the objective current should be set at a suitable reading and the image is brought into focus using the specimen "z" screw. Photographs of the grating should be taken at the magnifications used for the specimen. The negative of the grating is placed in the enlarger and the enlarger moved up or down until the distance between the lines on the easel is that given by the chart. For example, at 7,500 magnification, the distance between the lines on the easel should be 12.5mm. For accuracy, five lines should be measured or a distance of 62.5mm. Note in measuring lines, the distance from one point to where the pattern is repeated (e.g. left side of line to left side of line or centre to centre) should be taken. There are several advantages in the use of the grating. It makes an accurate record of the magnification used to be filed with your micrographs. It gives convenient round number magnifications (e.g. 10,000 not 9,879). It makes dark‐room enlarging easy and convenient. Magnification chart for enlarging Print magnification 1 line on easel (mm) 5 lines on easel (mm) 1000 1.67 8.35 2000 3.33 16.65 3000 5.00 25.00 5000 8.33 41.65 7500 12.50 62.50 8000 13.33 66.65 9000 15.00 75.00 10,000 16.67 83.35 11,000 18.33 91.65 12,000 20.00 100.00 13,000 21.67 108.35 14,000 23.33 116.65 Actual spacing of grating is 1667µm (15,240LPI) Intermediate Magnification Grating Replica Gratings are germanium shadowed carbon replicas made from a 28,800 line per inch diffraction grating. The actual grating spacing is 882 millimicrons. They are supplied mounted on grids as required by the customer. For accurate work, the microscope should be calibrated at each high voltage separately. For each magnification run, the objective current should be set at a suitable reading and the image is brought into focus using the specimen "z" screw. Photographs of the grating should be taken at the magnifications used for the specimen. The negative of the grating is placed in the enlarger and the enlarger moved up or down until the distance between the lines on the easel is that given by the chart. For example, at 25,000 magnification, the distance between the lines on the easel should be 22.1mm. For accuracy, six lines should be measured or a distance of 132.5mm. Note in measuring lines, the distance from one point to where the pattern is repeated (e.g. left side of line to left side of line or centre to centre) should be taken. There are several advantages in the use of the grating. It makes an accurate record of the magnification used to be filed with your micrographs. It gives convenient round number magnifications (e.g. 25,000 not 24,485). It makes dark‐room enlarging easy and convenient. Print magnification1 line on easel (mm)6 lines on easel (mm)Magnification chart for enlarging 2000 1.8 10.8 3000 2.6 15.4 5000 4.4 26.4 7500 6.6 39.4 10,000 8.8 52.8 15,000 13.2 79.2 20,000 17.6 105.6 25,000 22.1 132.5 50,000 44 75,000 66 100,000 88 150,000 132 Actual spacing of grating is 882µm (28,800LPI)
CDMS 1T Representative Traceability Certificate
CDMS‐ 1T, 2mm ‐ 1µm, Traceable Product Description: 2.5x2.5mm Critical Dimension Magnification Standard Wafer Identifier: CD‐PG01 The accuracy of these products was determined by reference comparison to working standards traceable to the National Institute of Standards and Technology (NIST), Test No. 861/280822‐11. Line Average pitch of wafer Number of lines averaged Average pitch uniformity (1σ uncertainty) Total expanded uncertainty (3σ) average pitch for wafer* 2.0mm 2.01mm 2 ± 4µm (±0.20%) ± 7µm (±0.35%) 1.0mm 1.00mm 2 ± 2µm (±0.20%) ± 3.5µm (±0.35%) 0.5mm 0.500mm 2 ± 1µm (±0.20%) ± 1.75µm (±0.35%) 0.25mm 0.250mm 2 ± 0.5µm (±0.20%) ± 0.9µm (±0.35%) 10µm 10.01µm 9 ± 0.02µm (±0.20%) ± 0.035µm (±0.35%) 5µm 5.00µm 10 ± 0.01µm (±0.20%) ± 0.0175µm (±0.35%) 2µm 2.00µm 10 ± 0.007µm (±0.35%) ± 0.014µm (±0.7%) 1µm 1.00µm 10 ± 0.0035µm (±0.35%) ± 0.007µm (±0.7%) * The 3σ uncertainty (95% confidence interval) average pitch is determined using a minimum of nine die per production wafer. Each average pitch is determined using 100 measurements on each die averaged over the stated number of lines. The total expanded uncertainty includes both Type A and Type B uncertainties corrected for sample size using an appropriate Student t‐factor. Equipment used: Instrument Model number Serial number Resolution Repeatability FE‐SEM FEI Quanta 3D FEG D8894 1.2nm 0.03% This certificate shall not be reproduced without permission. 682‐1 TN VPG‐01 09162011
Diffraction Standard Evaporated Aluminium
Aluminium Diffraction Pattern - S619 In order to use a standard in electron diffraction properly, several conditions are necessary: After obtaining the pattern of an unknown, it is necessary to expose the known standard to the same electrical and magnetic conditions, specifically the same lens current or high voltage. The specimen must be in the same position as the unknown had been. Small movements of the stage are permissible in order to obtain a clearer pattern of the standard. After developing the diffraction plates, the standard is measured first. The indices are assigned per the attached ASTM "d" spacings. After assigning the spacings, calculate "K" using the formula K = Sd; where "K" is a constant that represents wave length of the beam, camera length and associated variable crystallographic data, "S" is the diameter of the ring in cm and "d" is the interplanar spacing in angstroms. The values for "K" for the first five lines should be within 1% of each other. Use the mean value of "K". Next, the pattern of the unknown is measured, and using "K", determined from the standard, the "d" spacings of the unknown are calculated. It is then necessary to establish identity of the unknown from the ASTM published data. Aluminium: ASTM "d" spacings Miller Indices hk1 Lattice Spacing d (Å) Intensity I Lattice Constant a (Å) 111 2.338 100 4.050 200 2.024 47 4.048 220 1.431 22 4.047 311 1.221 24 4.0489 222 1.1690 7 4.0495 400 1.0124 2 4.0496 331 0.9289 8 4.0490 420 0.9055 8 4.0495 422 0.8266 8 4.0495 Average unit cell from last five lines..............................4.0494
Gold on Carbon Test Specimen
GENERAL INFORMATION These resolution test specimens provide a means of testing scanning electron beam microscopes. The various sizes of the gaps between gold crystals grown on a graphite substrate allow tests for the resolution attainable under real operating conditions. At the same time, the samples can be used to assess the quality of grey‐level reproduction at high resolution. High‐quality microscope instrumentation gives good results in the gap test combined with good grey‐level reproductions. Medium quality instruments may achieve a chosen gap resolution, but the grey‐level production may be quite poor. Typically, for example, only 4 or 5 grey levels may appear. Grey levels arise in the SE mode due to differential signal collection. This originates from geometric heterogeneities on the test specimen. For this reason, the angular crystal faces in the larger gold crystals can be used for the grey level assessment. As an aid in use, there is an outline image of a square mesh on the surface of the specimen. This is useful for preliminary focusing at magnifications below 150x. In addition, if the user wishes to preserve the specimen, then tests can be done on known areas, leaving other areas un‐irradiated. For a demanding assessment of the imaging qualities of the microscope, the microscopist may wish to view the very fine array of particles present in the boundary region between evaporated gold in the grid squares and uncoated graphite in the grid bars. When assessing the SE imaging chain, the sample is best viewed using a specimen tilt of 30 degrees to the SE collector. The stage tilt used in BSE testing will depend on the position of the detector. It is better not to view the sample in any mode with a tilt greater than 35 degrees since the height of the larger crystals may be such that the small crystals become shielded from view. If gap measurements are to be made it should be remembered that the magnification is not constant throughout the image when the sample is tilted. USING THE SPECIMEN Setting up the SEM: The gold crystals are difficult to visualise on the monitor when the SEM is working below 40000x magnifications. Other than giving this simple prescription, recommending conditions for SEM resolution and grey level testing is somewhat difficult since there are many levels of sophistication available in the instruments on the market. As a general guide, the operator will be aiming to use the test specimen at a fairly short working distance of say 7 or 8mm. The best probe sizes are available at higher probe energies, so a gun potential of 20kV or above should be chosen for the initial testing. Subsequently, it may be of interest to examine the performance of the SEM at lower gun potentials; however, unless the SEM in question has a dedicated facility for high quality imaging below 10keV, there will not be much point in attempting work at this level. It is important that the filament be correctly saturated and that the gun be working efficiently in terms of beam brightness and stability; that the apertures be carefully centered; and that the astigmatism and fine focus be carefully checked immediately prior to recording the image. For ultimate performance the stage should be mechanically stable, there should be a good chamber vacuum (you may have to wait some 3 or 4 hours to achieve this), the Gauss Maus. Note that the Gauss Maus makes peak measurements and not peak‐to‐peak. Some manufacturers quote peak‐to‐peak criteria for the minimum field requirements in the SEM environment, but the peak‐to‐peak figure is twice that measured using the Maus. For recording, if the variables are available, the largest number of scan lines per frame resolvable on the recording screen should be used. As well, a long recording time is recommended (up to 10 minutes may be available on some instruments). If the operator is looking for good grey level reproduction, it is very important that the recording camera lens be well focused and that the photographic processing be carefully controlled for the best gray range available. Measurements of gaps can, of course, only be made after a suitably exacting magnification calibration of the SEM. The microscopist must be satisfied that the calibration is rigorously applicable to the micrograph recorded of the Au/C test specimen. Set up the SEM, then insert the sample and await a good vacuum. Switch on the gun and saturate the filament carefully. Starting at a low magnification (below 150x), focus on the edges of the dark grid bars and search for a suitable square of gold. Raise the magnification to 500x and focus on a heterogeneous portion of the gold film. Increase the magnification to 40,000x, keeping the specimen in focus. Shift the specimen to image an area well within a grid square (if the stage is tilted, use X‐shift for convenience so that you don't lose focus); now focus carefully on the gold particles. Raise the magnification to 80,000x (or above) and make final adjustments to the stigmators and the fine‐focus controls. The latter adjustments should be performed quickly if the vacuum is contaminated in your SEM, since a heavy layer of contamination can be deposited even within a minute. Record the image using a very slow probe scanning rate. Each specimen has a square grid pattern with large crystals in the centre of each square and very fine crystals at the edges of each grid. Thus, medium and high resolution gap tests are performed on the same specimen. The larger crystals show facets which allow assessment of the gray level reproduction available at high resolution. For high resolution performance testing, the S015H has a smaller gold island particle size that the S015. The S015H is suitable for testing at instrument magnifications of 50,000x and above. The ultra high {please ask for price} is particularly suitable for assessing the image quality of high resolution SEMs such as those fitted with a field emission electron source. A magnification of at least 80,000x is required to clearly resolve the gold particles. Many of the instructions given on this technical note apply also to these ultra high resolution test specimens, but it should be noted that the instrumental magnification required to resolve the smaller particles will be higher. When operating at low accelerating voltages or using older instruments, difficulties may be experienced in imaging the standard gold on carbon resolution specimens. This may be due to inferior resolution at low voltage or poor signal to noise ratio when operating at high scanning rates with small spot sizes. The larger gold islands give high contrast while retaining small gaps for resolution measurement. This makes the specimen easier to use at non‐optimal operating conditions.
Gold Particle Stigmator (Unmounted & Mounted)
The gold particles, rather than having a "prickly" appearance, appear more like a pile of rocks, varying widely in shape and size. They have sharp, clearly defined edges and corners, making them ideal for determining and correcting astigmatism. This specimen is also ideal for determining resolution by measuring the spaces between smaller particles. The specimen material is 99.99% gold, mounted on a 1,000 mesh copper grid. It is highly conductive. Care of the Specimen: MOUNTED: Take care not to touch the specimen surface. When not in use, store the specimen in the original container or some other container where the surface is protected. UNMOUNTED: Use a dissection microscope when removing the specimen from the shipping container. Grip the grid gently, as close to the outer edge as possible. Do not lay the specimen face‐down on any surface. Never bend the grid, as this may cause the gold material to crack. Do not immerse the specimen in liquid of any kind.
Indium Wire, 4N Purity
Physical Properties of Indium Metal Indium was first discovered in Germany in 1863 and became the 49th element in Periodic Table. The name indium relates to its indigo blue spectral lines. The metal is a lustrous silver-white. It is very malleable and ductile and can be easily formed. It remains soft to temperatures approaching absolute zero, making it ideal for cryogenic and vacuum applications. Characteristics of indium include: Cold Welding: Oxide free indium has the unique ability to cold weld or attach to itself. Parts coated with indium can be bonded together without the addition of heat or chemicals. Metal Catalyst: Doping other pure metals with small amounts of indium, results in alloys that can be stronger or harder. For example, one of the first applications of indium is its addition to dental alloys. Improve Resistance to Thermal Fatigue: When indium is added to standard solder alloys, the joint is less likely to fail due to thermal fatigue. Reduce Gold Scavenging: When soldering to gold or gold-plated surfaces, solder has a tendency to dissolve gold into the joint. The addition of indium to the solder will reduce this tendency. Low Melting Point Alloys: Indium is often used to produce low melting point alloys which are used as fuses or temperature indicators. Low melting point alloys are also used in the optical industry to hold or "block" lenses during the polishing process. The polishing machine tool grip the alloy, not the lens, allowing the lens to be polished with minimised distortion. The alloy's low melting point then allows it to be removed from the lens with a minimum of heat and no damage. Join Materials with Different CTE's: Many times, materials being joined have different coefficients of thermal expansion (CTE). Traditional solder joints can crack during the expansion/contraction process because of this. Indium, when added to a solder alloy, provides ductility which can enable the materials to expand and contract at their individual rates while absorbing the CTE difference of the other material, all without cracking the bond. Bond Glass, Quartz and Ceramics: These materials cannot be bonded with traditional solders. Indium's unique cold welding properties allow it to produce a bond in a variety of non-metal applications. Reduce or Eliminate The Use of Lead and Mercury: The use of indium in most of today's alkaline dry cell batteries allows them to be more environmentally friendly by eliminating mercury and by delivering more energy per battery. In the soldering arena, indium-containing alloys are candidates for replacing lead-bearing alloys. Transparent Electrical Conductor: When indium (in the form of indium-tin oxide) is coated onto various materials such as glass or plastic films, it acts as a transparent electrical conductor and an infrared reflector. When architectural or photovoltaic glass is coated with indium-tin oxide (ITO) it keeps the harmful infrared rays of the sun from passing through. When coated onto automotive or aircraft windshields, it allows the glass to be electrically de-iced or demisted as well as reducing the air conditioning requirement by reducing heat gain. Malleable: Because indium is so soft and pliable (malleable), it can easily fill voids between two surfaces, even at cryogenic temperatures. PHYSICAL PROPERTIES OF PURE INDIUM Crystalline Structure Face-Centred Tetragonal: at 25C, a = 0.32525nm and c = 0.49465nm Atomic weight 114.82 Specific gravity: 20°C 7.30gm/cc 164°C 7.026gm/cc 300°C 6.916gm/cc THERMAL PROPERTIES Melting Point 156.6°C Boiling point 2080°C Coefficient of thermal expansion Linear, 24.8µm/m·K at 20 °C Specific Heat: 25°C 233J/kg·K 127°C 252J/kg·K 156.63°C (solid) 264J/kg·K 156.63°C (liquid) 257J/kg·K Latent heat of fusion 28.47 kJ/kg Latent heat of vaporisation 1959.42 kJ/kg Thermal conductivity 83.7 W/m·K at 0°C Vapour pressure: 1215°C 0.1013kPa 1421°C 1.013kPa 1693°C 10.13kPa 2080°C 101.3kPa ELECTRICAL PROPERTIES Resistance: 3.38 K ---- Super Conducting 20°C 84nW-m 154°C 291nW-m 181°C 301nW-m 280°C 348nW-m Electrochemical equivalent Valence 3, 396.4 µg/C Electrode potential InDeg/--> In3+ + 3e, 0.38V MAGNETIC PROPERTIES Magnetic susceptibility Volumetric: 7.0 x 10-6mks NUCLEAR PROPERTIES Stable isotopes 113, 115 Thermal neutron cross section. For 2.2 km/s neutrons: absorption, 190 ± 10b; scattering, 2.2 ± 0.5b MECHANICAL PROPERTIES Tensile Strength: 295K 1.6MPa 76K 15.0MPa 4K 31.9MPa Compressive strength 2.14 MPa Hardness 0.9 HB Elastic modulus at 20°C 12.74 GPa in tension Poisson's ratio at 20°C 0.4498
Lanthanum and Cerium Hexaboride (LaB6 and CeB6) Cathodes
Building the World's Best Cathodes Lanthanum hexaboride (LaB6) and cerium hexaboride (CeB6) cathodes are ideal for many small spot size applications such as SEM, TEM, surface analysis and metrology, and for high current applications such as microwave tubes, lithography, electron‐beam welders, X‐ray sources and free electron lasers. Applied Physics Technologies has decades of experience in research, development, and manufacturing of LaB6 and CeB6 cathodes. We can provide the cathodes you need for replacement, OEM, and custom applications. The unique properties of hexaboride crystals provide stable electron‐emitting media with work functions near 2.65 eV. The low work function yields higher currents at lower cathode temperatures than tungsten, which means greater brightness (or current at the beam focus) and longer cathode life. Typically, these cathodes exhibit 10 times the brightness and more than 10 times the service life of tungsten cathodes. In electron microscope applications, these characteristics translate to more beam current in a smaller spot at the sample, improved resolution, and less frequent cathode replacement. For applications with large beam spot sizes, where large total current and current density are required, large, flat crystal faces of LaB6 or CeB6 can be the cathodes of choice. This regime is unsuitable for point sources such as field emitters, which are unable to provide sufficient total current, and has been thought of as the realm of the dispenser cathode. However, LaB6 and CeB6 may be more suitable, being particularly robust and resistant to chemical poisoning. They have modest vacuum requirements and long shelf life, and need only be brought up to operating temperature to provide emission, eliminating the activation procedure required of dispenser cathodes. They can provide long‐term, stable operation at current densities up to 50 A/cm², and may be fabricated in a variety of shapes and with many different heating and mounting configurations. LaB6 and CeB6 are the materials of choice for high current cathodes in a variety of advanced and custom applications. The performance and lifetime of the hexaboride cathode are determined by several factors: vacuum level, cathode temperature, impurity level, crystal orientation, tip shape, and mount design. Vacuum requirements are more stringent for hexaboride emitters than for tungsten in order to minimise carbon contamination. In laboratory tests, CeB6 has proven to be more resistant to the negative impact of carbon contamination than LaB6, which gives it an edge in potential cathode lifetime. Excessive operating temperatures accelerate evaporation, thus decreasing the life of the cathode. Care must be taken to properly optimise cathode temperature to obtain the required emission without overheating the crystal. CeB6 has another advantage over LaB6 relating to lifetime: its evaporation rate at normal operating temperatures near 1800 K is lower than that of LaB6. So long as care is taken to operate the cathode below 1850 K, CeB6should maintain an optimum tip shape longer, and therefore last longer. CeB6 LaB6 Tungsten Filament Brightness (A/cm²‐sr) 107 107 106 Short‐term beam current stability % RMS <1 <1 <1 Typical service life (hr) 1,500 1000 30‐100 Operating vacuum (torr) 10‐7 10‐7 10‐5 Work function (eV) ~2.65 ~2.70 4.5 Evaporation rate (g/cm²‐sec) 1.6 x 10‐9 2.2 x 10‐9 NA A comparison of electron emission characteristics of LaB6, CeB6 and tungsten at typical operating temperatures Crystal Growth Hexaboride crystals are grown and purified in an inert gas atmosphere to specified crystal orientations. Impurities in the crystal will reduce both brightness and lifetime of the emitter because impurities increase both work function and volatility. We grow and fabricate our own high quality, single‐crystal materials using a well‐defined process called Inert Gas Arc Float Zone Refining.' An electric arc melts a pressed‐powder stick of LaB6 or CeB6 in a controlled atmosphere of inert gas, allowing the liquid‐phase zone to freeze onto a selected‐orientation seed crystal as the arc is moved along the stick. The finished crystal assumes the desired orientation of the seed with less than 30 parts per million by weight metal impurities. Correct melt zone temperature and process speed minimise excessive boron evaporation to achieve the optimum ratio of metal to boron atoms in the grown crystal. Crystal Orientation Crystal orientation can be selected to match the cathode design or application. For electron microscopy, the orientation is most desirable due to its brightness and crystal plane symmetry about the optical axis. As the cathode ages, the plane symmetry ensures an even evaporation rate relative to the axis, maintaining a centered, flat emitting surface (See figure). Also, the emission patterns from the symmetric crystal planes will remain consistent as they become more exposed by evaporation, contributing to a brighter beam spot. The "tophat" design cathode provides a large‐area crystal face electron source for maximum total current. Cathode Tip Design The design of the cathode tip is critical for maximum lifetime and optimum performance. Tip design must also match the specific application's requirements for beam current, spot size, and brightness. For electron microscopy, a conical tip with a flat emitting surface at the apex has proven to be the optimum design. With the flat‐tipped cone design, changes in both cone angle and flat diameter affect emission characteristics. In general, the small cone angle (60°) results in higher brightness, but a larger angle (90°) provides longer life and easier alignment. Small flat diameters also result in higher brightness plus a smaller source size, but larger flats provide longer lifetimes and more beam current. These trends allow us to tailor our cathodes to the requirements of practically all thermionic cathode applications. For example, SEM and most transmission electron microscope (TEM) applications are best served by a 90° cone angle and a 16 mm flat tip. This combination provides high brightness, a moderate source size, and very good lifetime. High resolution TEMs require a 60° cone and a 5 mm flat tip for very high brightness and a small source size. In applications requiring high total current in a large beam spot, aoriented crystal in a "top hat" configuration may be preferred, providing a slightly lower work function and large emitting surface. We excel at developing specialised cathodes for custom applications and research purposes. Contact us for your custom cathode needs. The cathode's mount design has a significant impact on performance. The design must be simple, durable and precise. It must resist any movement of the crystal, despite the high operating temperatures, yet be easy to install and align. We feel we employ the best mount design in the industry, the Mini Vogel Mount. In 1988, FEI of Hillsboro, Oregon introduced the Mini Vogel Mount (MVM) to provide the benefits of the original Vogel mount in a smaller, simpler, and more elegant design. Twin posts are rigidly fixed in a thick ceramic base, and bent towards the centre in an inverted "V". The posts are made of a molybdenum‐rhenium alloy that maintains a high modulus of elasticity even at high temperatures. The posts are spread slightly during assembly to allow placement of small pyrolytic graphite blocks between the crystal and posts. The blocks act as resistive heaters, and help thermally isolate the hot crystal from the highly conductive posts. When the compressive force of the posts is released, the crystal is held with strength and precision. The clamping force of the posts will remain near 5,000 psi for the life of the cathode. The structure of the MVM is amazingly robust, sustaining reasonable impact without deviating from structural specifications. Because the graphite pads shield evaporation of the crystal in the direction of the clamping force, the emitter crystal can be fully utilised without degradation of the mount. Structural failure of the MVM is not a concern when the cathode is operated within the correct temperature and pressure range. Typically, the beam stability of the Mini Vogel Mount cathode exceeds the specifications of the system in which it runs. Kimball Physics Lanthanum Hexaboride (LaB6) Cathodes Featuring Extended Life ‐ Thousands of Hours in Clean Vacuum. Guaranteed Life (Measured in Surface Loss). Guaranteed Against Mounting Structure Failure. Exceptional Stability ‐Thermal/Chemical/Electrical. Precision Machined Carbon Mounting. Highover‐Temperature Tolerance. High Brightness/Low Energy Spread ‐ Oriented Single Crystal. Best‐Quality/High‐Purity Material. Accurate Microflats ‐Superior Optics/Controlled Source Size Standard Diameter Available. For Use in Scanning Electron Microscopes Transmission Electron Microscopes Electronlithography Systems X‐Ray Sources The new improved Kimball Physics Model ES‐423E (Extended Life) LaB6 Cathode is a high performance, resistively heated, thermionic electron source. The improvement stability of the LaB6 crystal, results in less exposure of LaB6, which reduces Wehnelt aperture contamination. Its lifetime is in excess of 6 months with continuous operation. Continuous operation at the full operating temperature improves the thermal stability of the gun and hence beam current stability. It is no longer necessary to wait hours for stable beam conditions in order to perform quantitative EEL or EDX measurements. Specifications The emitter is machined to 15 /‐2µm diameter (standard), microflat alignment to the instrument base can be provided (on request), oriented‐single‐crystal, surface. Mounted on the end of a single‐piece, stress‐free, carbon heater rod, held in place by a carbon ferrule. A high degree of axial symmetry provides great mechanical stability. The rod has a 100µm slot along the axis, which allows the heating current to go up one side and down the other. In SEM type instruments, its lifetime is up to 3000 ‐ 4000 hours In TEM instruments the lifetime can be even longer. Mounting structure will last more than 10,000 hours. Chemical reactivity and mechanical drift problems have been eliminated. Instrument Conditions While the cathodes can be fitted to virtually any instrument, there are several requirements needed for achieving quality results. The most important requirement is for clean vacuum, with partial pressures of oxidising gases being kept below 10‐7 torr in the electron gun. The condition of the cathode itself, along with that of the Wehnelt aperture, may often be used to verify the partial pressures in the gun. The cathode must be accurately and correctly positioned behind the Wehnelt aperture. There must be controllable bias resistors which can reach adequately high values; some instruments are limited by values which are to low.
Latex Flow Cytometry Particles 0.1%
Particle Concentration: 0.1% w/v Preservative: 0.01% MP40 and 0.02% Sodium Azide Storage: Below 30°C. Refrigeration is usually not required. CAUTION: DO NOT FREEZE. Note: Before use, resuspend by vortexing. To achieve optimum particle suspension, briefly sonicate the reagent after vortex mixing. Code Lid Colour Qty Particle size distribution analysis Nominal Mean Standard deviation C.V SL‐001S White 5ml 0.1µm 0.095µm 0.0023 2.4% SL‐003S Blue 5ml 0.3µm 0.31µm 0.0074 2.4% SL‐005S Green 5ml 0.5µm 0.53µm 0.0125 2.4% SL‐008S Yellow 5ml 0.8µm 0.82µm 0.0192 2.4% SL‐010M White 5ml 1.0µm 1.0µm 0.024 2.4% SL‐020M Blue 5ml 2.0µm 2.38µm 0.057 2.4% SL‐030M Green 5ml 3.0µm 3.17µm SL‐050M Yellow 5ml 5.0µm 5.26µm SL‐080L White 4ml 8.0µm 7.9µm SL‐100L Blue 3ml 10.0µm 10.0µm SL‐150L Green 2.5ml 15.0µm 15.5µm SL‐200L Yellow 2ml 20.0µm 20.1µm *WARNING: Sodium Azide Cu react with Cu and Pb in plumbing to form explosive metal azides. Flush this reagent down drains with copious amounts of water. NOTE: FOR RESEARCH APPLICATIONS ONLY. NOT FOR DIAGNOSTIC USE. SL‐001S ‐ SL‐5L ‐ Latex Calibration Particles
Latex Spheres Test Specimen
This test specimen consists of 0.261 micron diameter Latex Spheres shadowed with gold. The gold forms islands of electron dense material suitable for determining instrument resolution by the particle separation method. The fines particles can be usually be located around the edges of the "shadow" areas. CARE OF THE SPECIMEN: Use a binocular microscope when removing the specimen from the plastic vial to ensure that only the extreme edge of the grid is held in the forceps. Place the grid directly into the microscope specimen holder if possible. If the grid must be laid down, do so only on a lint free surface with a darker, more reflective side of the grid facing up (the specimen side).
Lattice Plane Resolution Tests
The resolution of crystal lattice planes is a useful test of the performance of an electron microscope, particularly mechanical and electrical stability. The crystal spacings are known accurately from X-ray data, so the high magnification used can be calibrated with accuracy. Mounting Crystal specimens are mounted on perforated carbon films. Selection and Placement Wherever possible, thin crystals that cross one of the holes should be selected so that support film structure does not interfere. Good crystals can usually be located by checking the selected area diffraction pattern - unless a clear single crystal pattern is obtained, the lattice planes will not be observed. Method When a suitable crystal has been selected a very high electron optical magnification should be used, so that the lattice planes can clearly be resolved on the fluorescent screen under the viewing telescope. The objective lens focus has to be adjusted carefully to optimise the contrast. The phase contrast of a given crystal lattice spacing is critically dependent on the amount of objective lens defocusing. If the contrast is inadequate, a significant improvement may be obtained by defocusing the condenser lens (reduction of illumination semi-angle). Further improvement is possible by tilting the illuminating beam so that the central beam and first order diffraction spot are symmetrical about the instrument axis (take care that the objective aperture is large enough to accept the diffracted beams). calibration
MAG*I*CAL™ Ultimate Calibration Standard for TEM
The MAG*I*CAL™ Calibration Standard goes through a stringent quality control process during and after production which ensures that you will receive a high quality calibration standard. If you are having trouble making effective use of the MAG*I*CAL™, please go through the following steps and determine the cause. Step 1: When the sample was sent, colours were visible (under an optional microscope) around the central perforation - 'white' (clear) nearest the hole, then yellow, orange, and increasingly deep shades of red. Are these colours still visible? If they are, the sample is probably undamaged. Step 2: The central hole should be roughly circular or oblong. If this is so, the sample is probably undamaged. If the central perforation has angular, jagged edges, the sample has been damaged but the useful calibration area may still be intact. Step 3: Have you looked at the MAG*I*CAL™ in the TEM? Did you carefully follow the instructions? Alignment is critical, and if you are not used to looking at the epoxy line where the two pieces of calibration material have been joined, then please note that the arrows point to the areas where the calibration-marks can be found. All you need is one! The extras are redundant. Move around the central perforation and find all four calibration-mark areas. You may need to adjust the sample tilt when you move over the epoxy line between the two pieces of calibration material. If none of the four areas is useful, the sample is damaged and should be returned. Step 4: If the sample was damaged by handling, (e.g. poking tweezers through it, fracturing it while removing it from the container, dropping it and having pieces fracture off, etc.) the sample is not returnable.
Magnification Calibration Diffraction Grating Replicas
GTP606/GTP607 This specimen is a replica of a 2160 lines/mm parallel line diffraction grating. When imaging the specimen, it should be kept in mind that the line spacing is 0.463µm and the pattern will not be visible until the imaging system is set to resolve that level of detail - around x2,500. At this magnification, the lines of the pattern will be just over 1mm apart. To calculate the electron microscope magnification using the pattern of the diffraction grating replica: Take the measurement, in millimetres, between as large a number of lines of the replica pattern as possible. Apply the following formula: Magnification = A x 2160/B A is the distance, in mm, between the first and last line measured. B is the number of spaces between the first and last line measured. (Alternatively, use the PELCO ® Magnification Calibration Calculator, Prod. No. 252.) Care of Grating Replica Specimen When not in use the replica should be kept in the vial. The replica surface may be damaged if touched. Never try to clean it. Care must be taken to avoid bending the grid as distortion may cause the replica film to fracture. When viewing in the TEM begin at low magnification with a low illumination level. Increase the illumination a little beyond comfortable viewing level then reduce it. This helps to stabilise the specimen. Before moving the specimen to view another grid square, reduce the illumination and magnification to starting levels again.
Molybdenum Trioxide Crystals, Image Rotation
This test specimen is most useful to determine the rotation between a diffraction pattern and the selected area image. Select a thin crystal, not overlaid by others, so that a clear Laue diffraction pattern is obtained (see illustration). Starting from the diffraction pattern, change the strength of the diffraction lens until each diffraction spot shows a small image of the crystal. It will be possible to determine the sense of the rotation of the image as the magnification is increased. Check whether there is an image inversion between the diffraction position and selected area magnification. The actual magnitude of the rotation angle between the crystal and its pattern can be determined by recording both image and diffraction pattern on a single photographic plate. The correct rotation angle between pattern and image can then be determined by taking into account the sense of rotation and any image inversion. NOTE: After removing this specimen from the EM, the specimen holder should be cleaned of any adhering molybdenum trioxide.
Muscovite Mica Grades
EMS Mica Sheets offer a clean surface for EM applications, carbon filming and particle spraying, as well as for AFM applications. There are two types of mica: muscovite and phlogopite. Generally, one differs from the other by colour (Muscovite is Ruby, Green or White; Phlogopite is Amber, Yellow, or Silver). The maximum operating temperature for Muscovite is about 500-600°C and for Phlogopite is about 800-900°C. Our line consists of High Quality Muscovite Mica. This mica peels off very thin up to 0.0001" uniform layers, exposing "virgin" mica upon splitting. The highest quality distinction of the mica: High quality (V-1 or V-2) to the Medium Quality (V-4 to V-6) The quality of muscovite mica is verbal determination by visual quality classification ASTM (D351-57T) from the best V-1 to the worst is V-10A. 1. V-1: Clear - Hard, of uniform colour, nearly flat, free of all stains, foreign inclusion, cracks, and other similar defects. 2. V-2: Clear and Slightly Stained - Hard, of uniform colour, nearly flat and may contain slight crystallographic discolouration, and very slight air inclusions and not more than one fourth of the usable area. 3. V-3: Fair Stained - Hard, of uniform colour, may contain slight waves, slight crystallographic discolouration, and slight air inclusions and not more than one-half of the usable area. 4. V-4: Good Stained - Hard, of uniform colour, may contain medium waves slight crystallographic discolouration, and medium air inclusion in not more than two-third of the usable area. 5. V-5: Stained A Quality - Hard, may contain medium air inclusions, uniformly distributed in the usable area; slight green vegetable stains, medium waviness, and heavy waves if specified. 6. V-6: Stained B Quality - Hard, may contain heavy air inclusions and heavy waves, medium green vegetable stains, slight black and red dots (mineral) and clay stains. 7. V-7: Heavy Stained - Hard, and may contain heavy air inclusions and waves, slight light black and red dots (mineral), medium cloudy stains, clay stains and green stains (vegetable). Soft, buckles, ridges, and sand blast acceptable if specified. 8. V-7A: Densely Stained - Hard and soft. May contain heavy waves and air inclusions, cloudy stains. High black and red dots (mineral). Medium black and red stained (mineral), buckles, and ridges. Also, green stain (vegetable type), clay stains, herring bones, and sand blast. 9. V-8: Black Dotted - Hard, may contain medium waves, heavy air inclusions, cloudy stains, light black and red dots (mineral), and green stains (vegetable). 10. V-9: Black Spotted - Hard, may contain medium waves, heavy air inclusions, cloudy stains, light black and red dots (mineral), and green stains (vegetable type), slight black stains (mineral), and sand blast. 11. V-10: Black Stained - Hard, may contain medium waves, heavy air inclusions, cloudy stains, light black and red dots (mineral), green stains (vegetable type), and sand blast, medium black stains (mineral), slight red stains (mineral), and clay stains. 12. V-10A: Densely Black and Red Stained - Hard, may contain heavy waves, air inclusion, cloudy stains, light black and red dots (mineral), red stains (mineral), black and red stains (mineral), green stains (vegetable type), and sand blast, very dense black and red stains (mineral), and slight clay stains. Soft if specified. Characteristics: Muscovite, potash type mica, also called granitic mica, is indeed the greatest of all micas in dielectric power, cleavage perfection and clarity. It has the following chemical formula: H2KAI3(Si04)3. Chemical Composition: Silica: 45.5% Alumina: 37.5% Potash: 12.0% Water: 5.00% It has a vitreous lustre and is colourless to grey, brown, pale green, violet, dark olive green, or rose red. It may be transparent to translucent. It has strong double refraction and is optically negative. It loses water of constitution at 600°C and is practically non-magnetic. It exhibits pleochrism, which is the property of varying in colour when viewed from different angles. RUBY muscovite is harder than green and has a pale brownish red colour in thin sheets (0.020") or ruby red in thick plates (0.4"). Ruby mica can be split easily into films of 0.001" or thinner because it has such excellent cleavage. In other colours, this thinness can be obtained but at a considerable risk of cracking. Physical Properties: Hardness: Moh's scale: 2.8 - 3.2 Shore's Test: 80 - 150 Specific Gravity: 2.6 - 3.2g/cm3 Tensile Strength: ~ 1750kg/cm2 Compression Strength: 1900 - 2850kg/cm2 Refractive Index (air=1): 1.56 - 1.60/61 Dielectric Strength @20°C in volt/mil: 3,000 - 6,000 Maximum Thermal Resistance: 625°C (1,157°F) Modulus of Elasticity, : 1400 - 2100kgf/cm2E(-3) Optic Axial Angle: 50° - 75° Coefficient of Expansion per °C: Perpendicular to cleavage plane 9E(-4) - 36E(-4) Calcining Temperature 700 - 800°C Thermal Conductivity: ~0.0013gm.cal/sec/cm2/°C/cm Water of Constitution: 4 - 5% Moisture Absorption: Very low Apparent Electric Strength: (0.001-0.003" thick) 120 - 200kV/mm Permittivity @ 15°C: 6 - 7 Power Factor (loss Tangent) @15°C: 0.0001 - 0.0004 Volume Resistively @25°C: 4E(-15) - 2E(-17)Ohm.cm Acid Reaction: Affected by HF Applications: In general, for those whom are using mica for the making of carbon support films, thin films coatings research, and some AFM studies where HOPG are used to taking place, the mica V-4 or V-5 is recommended. (Mica must always use freshly cleaved surfaces). For AFM and SPM calibration, V-1 or V-2 is recommended. However, we believe that it is important that you know what kind of mica is being used in your lab. The information on the mica as given above should be used to make your choice.
Orientated Gold Crystal Lattice For TEM
User notes for orientated gold crystal lattice on 3mm grid, for TEM, S646. The resolution of crystal lattice planes is a useful test of the performance of an electron microscope, particularly mechanical and electrical stability. The crystal spacing's are known accurately from X-ray data, and therefore the high magnification used can be calibrated with accuracy. The crystal specimens are mounted on perforated carbon films. Wherever possible, thin crystals that cross one of the holes should be selected so that interfering structure from the support film is not encountered. Good crystals can usually be located by checking the selected area diffraction pattern; unless a clear single crystal pattern is obtained, the lattice planes will not be observed. When a suitable crystal has been selected, a very high electron optical magnification should be used, so that the lattice planes can clearly be resolved on the fluorescent screen under the viewing telescope. The objective lens focus has to be adjusted carefully to optimise the contrast. The phase contrast of a given crystal lattice spacing is critically dependent on the amount of objective lens defocusing. If the contrast is inadequate, a significant improvement may be obtained by defocusing the condenser lens (reduction of illumination semi-angle). Further improvement may be brought about by tilting the illuminating beam so that the central beam and first order diffraction spot are symmetrical about the instrument axis (take care that the objective aperture enough to accept the diffracted beams). The approximately 11nm thick evaporated gold is induced to grow in a (100) orientation. This gives lattice plane spacings of 0.204nm for the (200) planes and 0.143nm for the (220) planes. If the crystal thickness happens to be suitable, and if the objective aperture is large enough to accept the required diffraction beams, a spacing of 0.102nm can be imaged with a suitable focal setting. This specimen thus provides a valuable test for the best microscopes in service.
PELCO polished quartz disc substrates
GE 124 Quartz Material Composition The fused quartz material used for our Quartz Discs, Quartz Microscope Slides, and Quartz Cover Slips is a high quality, high purity GE124 quartz. This quartz material is well documented and used in many microscopy applications. Fused quartz is an amorphous, glassy material. Typical Trace Element Composition (ppm by weight) Analysis via Direct Reading Spectrometer Type Al As B Ca Cd Cr Cu Fe K GE 124 14 <0.002 <0.2 0.4 <0.01 <0.05 0.05 0.2 0.6 Li Mg Mn Na Ni P Sb Ti Zr *OH 0.6 0.1 <0.05 0.7 <0.1 <0.2 <0.003 1.1 0.8 <5 Typical Physical Properties Density 2.2 x 103 kg/m3 Refractive index 1.4585 Softening point 1683°C Annealing point 1215°C Strain point 1120°C Hardness 5.5 - 6.5 Mohs Scale Compressive Strength 1.1 x 109 Pa (160,000 psi) Tensil strength 4.8 x 107 Pa (7000 psi) Electrical resistivity @350°C: 7 x 107 ohm/cm Young's Modulus 7.2 x 1010 Pa (10.5 x 106 psi) Thermal Expansion Coefficient 5.5 x 10-7 mm/mm.°C Thermal Conductivity 1.4 w/m.°C Optical Transmission The curve shows the typical optical transmission curve with the absorption edges for GE 124 from the UV through visible into the infra-red range. In the typical 250-290nm range for UV microscopy applications the material exhibits excellent transmittance. Fused Quartz Average Transmisstion Curves Surface Finish Our slides and coverslips have a surface flatness of ±1 degree, with 60/40 scratch/dig specification. 60/40 scratch/dig has the following definition: Visibility Method Scratch/Dig: Surface quality is specified by a number such as 60/40. The 60 defines a scratch width according to a visual standard (it does not mean a scratch can be 60 um wide). For reference, scratch numbers of 60 typically refer to maximum allowable scratch widths of ~7um to 8um. With this in mind, the scratch part of the specifications includes the following four requirements: The combined length of the scratches with the specified scratch number shall not exceed 25% of the smallest dimension of the clear aperture. When scratches with the maximum allowable scratch number are present, then the sum of the products of the respective scratch numbers times the ratio of their length to the smallest dimension of the clear aperture for all scratches cannot exceed 50% of the maximum allowable scratch number. When scratches with the maximum allowable scratch number are not present, then the sum of the products of the respective scratch numbers times the ratio of their length to the smallest dimension of the clear aperture for all scratches cannot exceed the maximum allowable scratch number. Surface with scratch letter requirements between 10 and 20 can have no more than 4 separate scratches in any 0.25 inch circular area. The second number of the Scratch-Dig specification refers to digs, and establishes a limit to the actual size (diameter) of the digs in hundredths of a millimeter. The dig part of the specifications includes the following three requirements: The maximum number of digs must be less than 1 per 20mm diameter circle. For every 20mm diameter clear aperture, the sum of the diameters of all digs exceeding 2.5um in diameter cannot exceed 2 times the specified dig letter. Digs with a dig number less than 10 must be at least 1mm apart. 60/40 equates to a Ra of 0.16u (40Å) Scratch/Dig Angstroms Ra Microinches Ra 10/5 10A 0.040u" 20/10 20A 0.080u" 40/20 30A 0.12u" 60/40 40A 0.16u" 80/50 50A 0.2u"
QUANTIFOIL®
QUANTIFOIL is a perforated support foil with pre-defined hole size, shape and arrangement. It has advantages in electron microscopy (EM) or low-energy electron point source (LEEPS) microscopy when compared with conventional holey film. QUANTIFOIL is offered with circular and square, orthogonal arranged holes. Films with different hole sizes and bar widths are available. Carbon is the standard material that makes the foil but gold and SiO2 is also available. General Information: 1. Hole Size: Refers to the diameter of the individual holes in the film. The hole size determines how much of the sample is unsupported and visible through the grid, which is crucial for applications like cryo-electron microscopy (cryo-EM), where the sample sits in the holes for optimal imaging. 2. Spacing: This is the distance between the centres of adjacent holes in the QUANTIFOIL film. Spacing affects how densely the holes are packed across the film and, consequently, the distribution of the sample on the grid. 3. Period: This refers to the repeating pattern of holes across the grid film. It is defined by the combined length of the hole and the surrounding film that separates each hole, creating a repeating lattice structure. QUANTIFOIL HexAuFoil® SPT Labtech are now scaling up full production of HexAuFoil® ultra-small hole gold-on-gold grids. Developed at the MRC Laboratory of Molecular Biology, Cambridge, UK and requiring a completely novel production process to deliver the dense array of 300 nm holes, these grids offer:Virtually movement-free imaging. Consistent, thin (approx 35nm) ice across 9m holes on each grid. The possibility of zero dose reconstructions for the first time. Improved stability, less re-focusing and faster data collections, due to their dense, hexagonal design. An ideal solution for cryo-EM scientists in industry or academia looking to maximise output of high-quality reconstructions for SBDD and academic research. These grids are a pre-production version supplied by SPT Labtech, they may differ in their detailed appearance from the final product which will be available on the website soon. Despite these differences, they will still deliver the expected benefits of the HexAuFoil® technology, including consistently thin ice that enables the virtual elimination of beam-induced particle motion. QUANTIFOIL® Holey Carbon Support Holey Carbon supports are a flat film of carbon, 10-12 nm thick, on a cryo-electron microscopy (cryo-EM) grid. They provide a low-background sample support ideal for high-resolution cryo-EM data collection. The optimum grid for your project can be selected from a wide variety of hole shapes, sizes and spacings in combination with a range of base grid materials and mesh sizes. Grid options include standard square meshes as well as other arrangements and finder grid formats. Circular - Ideal for high-resolution studies of biological macromolecules and other materials, round holes optimise the formation of a thin, even layer of ice to support a sample of interest. Select from our wide range of geometries depending on the characteristics of your sample and your imaging modality. Square - Often used for applications where larger carbon-free areas are desired, square grids have less carbon support. They can be used with an additional thin carbon layer where samples need continuous support. Multi A - With a repeating pattern of hole size, shape and spacing, Multi A foils are useful for particles of unpredictable size, for example liposomes, while the oval shape can aid in tomographic data collection. HOW TO PREPARE HOLEY CARBON FILM SUPPORTS QUANTIFOIL® UltrAuFoil Better 3D reconstructions from less data with ultra-stable gold supports for cryo-electron microscopy that reduce the movement of frozen specimens during imaging. Designed at MRC's Laboratory of Molecular Biology by Dr Christopher J Russo and Dr Lori A Passmore and manufactured exclusively under license by Quantifoil Micro Tools GmbH1, UltrAuFoil® Holey Gold sample supports make structure determination for challenging and small molecules easier. During imaging at cryogenic temperatures, traditional carbon supports move, particularly at the beginning of irradiation. This movement blurs images and reduces data quality. UltrAuFoil® Holey Gold supports are more conductive, and there is no differential contraction between the grid and the foil on plunge freezing. Therefore, there is less crinkling of the foil during sample preparation, resulting in many improvements in data quality. UltrAuFoil® Gold supports for better reconstructions with less data Increases resolution, by up to 0.5 Å when replacing traditional holey carbon supports with UltrAuFoil®. Reduces image distortion from the accumulation of static and semi-mobile charge as gold is highly conductive at liquid nitrogen temperatures. Protects samples from damage due to accumulating positive charge by neutralising it with secondary electrons generated by irradiating adjacent gold. Allows biomolecules to retain native structure and by not putting them under mechanical strain from foil crinkling. Improves particle distribution as the gold foil is even flatter than carbon, and capable of forming the <200 Å ice layers required for ultra-high resolution data collection on smaller molecules. Simplifies grid surveying due to the high contrast of the gold foil. Additional Ultrathin Continuous Carbon Layer Particle density and distribution has been widely shown to improve on the addition of an ultrathin (2-3nm) carbon (UTC) layer to a grid. Data quality has improved for both QUANTIFOIL 4 Holey Carbon Films and UltrAuFoil 5 Gold Supports when a UTC layer is applied. An additional UTC layer can be added to most QUANTIFOIL Holey Carbon Film supports on request. The most popular thickness is 2nm, but thicker, more stable, 3 and 5nm layers are also available, and even 10nm is possible. For an additional UTC on QUANTIFOIL Holey Carbon Film supports, please request a quote. Alternatively, if you are interested in adding a UTC layer to UltrAuFoil Holey Gold supports, please contact us for further details. PLEASE NOTE - As the ultrathin carbon layer may not be as stable as our usual films, we recommend using grids with a UTC layer within 6 months of delivery. Improvements in specimen quality Shown in the image is the structure of Photorhabdus luminescens TcdA1, a large multisubunit complex toxin, with activity against insects, whose structure was determined using images collected on QUANTIFOIL® R 2/1 grids with a 2nm additional carbon layer6. Many biomolecules have a strong affinity for carbon, and a number of factors contribute to a resulting improvement in specimen quality: Increased numbers of particles due to adsorption of biomolecules onto carbon prior to blotting. Improved particle distribution due to interaction with carbon surface across the hole. Reduction in the number of particles adopting a preferred orientation. QUANTIFOIL® SiO2 Films Methods development for in situ structural investigation by FIB-milling and cryo-electron tomography Toro-Nahuelpan et al. Tailoring cryo-electron microscopy grids by photo-micropatterning for in-cell structural studies. Nat Methods 17: 50-54 (2020) Lucas and Grigorieff. Quantification of gallium cryo-FIB milling damage in biological lamellae. Proc. Natl Acad. Sci. USA 120: e2301852120 (2023) Franken et al. Protocol for live-cell fluorescence-guided cryoFIB-milling and electron cryo-tomography of virus-infected cells. STAR Protocols 3: 101696 (2022) Recent examples of Cryo-ET investigations using SiO2 grids Shepherd et al. Throughput-scalable manufacturing of SARS-CoV-2 mRNA lipid nanoparticle vaccines. Proc Natl Acad Sci USA 120: e2303567120 (2023) Winter et al. The Ebola virus VP40 matrix layer undergoes endosomal disassembly essential for membrane fusion. EMBO J 42: e113578 (2023) Zhang et al. Molecular mechanisms of stress-induced reactivation in mumps virus condensates. Cell 186: 1877-1894 (2023) QUANTIFOIL® Active Self-wicking grids for use exclusively with SPT Labtech chameleon. QUANTIFOIL® Active grids are unique in being the first commercially produced grids with copper nano-wire covered bars to promote thin film formation through a process of “self-wicking”. Brought to you in collaboration with our sister company SPT Labtech, these supports eliminate the variability of using an externally applied filter paper to remove excess sample during blotting. Only for use in single particle cryo-EM studies with the SPT Labtech chameleon: Automatic sample preparation with chameleon streamlines cryo-EM workflows with high speed blot-free vitrification, automated grid handling, and the ability to screen grids based on likely ice thickness.
Reference Standards for UHV-EL Retainers
Round UHV-EL Retainer can be ordered in Standard or Custom Configuration The Standard Configuration is shown below. A custom configuration requires that details be given regarding the elements chosen and the configuration (a "blank" Custom Round Retainer is shown for ordering - please print out and fill in exactly as needed). Fig.1 Standard Configuration for Round Retainer See below for a list of elements and compounds, preceded by their respective order numbers. Reference Standards for UHV-EL Retainers Abbreviations: M - Natural mineral Opt - Optical crystal P - Powder or grains: mixed with either Ag or Sn (for S containing materials) and pressed TF - Thin film on silicon wafer VD - Vapour deposit (CVD, LPCVD, etc.) B - Bulk material C - Crystalline EM - End member mineral F - Foil HP - Hot pressed Purity - "N" is the # of "9"'s. 5N stands for 99.999% pure, 2N5 is 99.5% pure "+" - Higher purity ? - No certificate available. Most original containers with marked purity. With EDS analysis we see no additional elements (>0.1%) * - These standards are very sensitive to humidity and should be kept in vacuum. We suggest using Vacu-Storr Desiccators. Code Symbol Form Purity Code Symbol Form Purity 1 Aluminium Al F 4N 75 Mercury Sulfide HgS P 4N5 ? 2 Aluminium Fluoride AlF3 P 2N5 75A Mercury Telluride HgTe C 5N 3 Aluminium Oxide Al2O3 C 4N ? 76 Molybdenum Mo C 4N 4 Aluminium Nitride AlN P 2N+ 76A Molybdenum Boride MoB P 2N 5 Antimony Sb B 4N8 77 Molybdenum Carbide Mo2C F 3N5 ? 6 Barium Fluoride BaF2 C 2N 78 Molybdenum Silicide MoSi2 HP 3N 7 Barium Sulfate BaSO4 P 3N ? 79 Molybdenum Oxide MoO3 P 2N5 ? 8 Barium Titanate BaTi4O9 HP 2N5 ? 81 Osmium Os P 4N5 9 Barium Titanate BaTiO3 P 3N 81A Neodymium Fluoride NdF3 F 3N 10 Beryllium (For Sale in U.S.A. Only) Be F 2N 81C Neodymium Oxide Nd2O3 P 2N8 11 Bismuth (For Sale in U.S.A. Only) Bi B 6N ? 82 Nickel Ni C 4N4 12 Bismuth Oxide (NO EXPORT) Bi2O3 P 2N5 ? 82A Nickel Aluminide NiAl F 2N5 12A Bismuth Telluride (For Sale in U.S.A. Only) Bi2Te3 B 5N 83 Nickel Oxide NiO F 3N5 ? 13 Boron B B 2N5 84 Nickel Phosphide Ni2P P 3N 14 Boron Carbide B4C P 5N ? 85 Nickel Silicide NiSi2 P 3N ? 15 Boron Nitride BN B 4N 86 Niobium Nb P 3N7 16 Boron Phosphide BP P 3N 87 Niobium Carbide NbC P 2N5 ? 17 Cadmium Cd F 4N7 88 Niobium Oxide Nb2O5 HP 3N5 ? 17A Cadmium Sulfide CdS P 3N 88A Niobium Nitride NbN P 2N5 17B Cadmium Telluride CdTe B 5N 89 Palladium Pd P 3N 18 Calcium Carbonate CaCO3 C 3N ? 90 Platinum Pt F 3N 19 Calcium Fluoride CaF2 C 3N 91 Potassium Bromide KBr F 4N ? 20 Carbon (Pyrolytic) C CVD 3N ? 92 Potassium Chloride KCl C 3N5 ? 21 Carbon (Diamond), same as #168 (additional cost) C (cleaved ~1mm) C ? 93 Potassium Iodide KI C 3N ? 22 Cerium Oxide CeO2 P 2N1 93A Praeseodymium Fluoride PrF3 C 3N8 23 Cesium Iodide CsI O * 2N ? 94 Rhenium Re HP 3N7 23A Cesium Bromide CsBr P * 4N 94A Rhenium Oxide ReO F 3N ? 24 Chromium Cr P 4N6 96 Rhodium Rh W 2N8 24A Chromium Carbide Cr3C2 P 2N8 97 Rubidium Chloride RbCl F 3N ? 25 Chromium Nitride Cr2N P 2N5 97A Rubidium Iodide RbI P 2N7 26 Chromium Oxide Cr2O3 HP 5N 98 Ruthenium Ru P 3N 27 Cobalt Co F 5N 99 Samarium Sm P 3N 28 Cobalt Oxide Co3O4 P 3N 100 Scandium Sc F 2N9 29 Cobalt Silicide CoSi2 P 2N 101 Selenium Se C 3N 29A Cobalt Sulfide CoS P 2N5 102 Silicon Si C 5N 30 Copper Cu F 4N5 103 Silicon Carbide SiC CVD Opt ? 31 Cupric Oxide CuO P 3N 104 Silicon Dioxide SiO2 EM 2N5 ? 32 Cuprous Oxide Cu2O EM 3N 105 1000Å SiO2/Si SiO2 TF 3N5 32A Copper Selenide CuSe B 2N5 106 Silicon Nitride Si3N4 HP 2N 33 Copper Sulfide CuS M 3N 107 468Å Si3N4/Si Si3N4 TF 2N5 34 Copper Sulfide Cu2S M 2N+? 108 Silver Ag F 3N 35 Dysprosium Dy F * 3N 109 Silver Chloride AgCl C * 5N 36 Erbium Er F * 3N ? 109A Silver Oxide Ag2O P 3N ? 37 Europium Oxide Eu2O3 HP 3N 110 Silver Sulfide Ag2S C ? 38 Gadolinium Gd F * 3N ? 111 Sodium Chloride NaCl C 2N5 39 Gallium Arsenide GaAs C 5N ? 112 Sodium Fluoride NaF C 5N 40 Gallium Nitride GaN P 3N 113 Strontium Fluoride SrF2 P 3N 41 Gallium Phosphide GaP P 2N5 114 Tantalum Ta F 3N5 42 Gallium Antimonide GaSb P 2N5 ? 115 Tantalum Carbide TaC HP 3N ? 42A Gallium Selenide GaSe P 4N 116 Tantalum Nitride TaN P 4N8 42B Gallium Sulfide Ga2S3 B 4N 117 Tantalum Oxide Ta2O5 P 1N8 ? 43 Germanium Ge B 2N 118 1000Å Ta2O5/Ta Ta2O5 TF 2N 44 Germanium Oxide GeO P 2N5 120 Tantalum Silicide TaSi2 P 2N5 45 Gold Au F 4N 121 Tellurium Te B 5N 46 Hafnium Hf F 2N5 ? 122 Terbium Tb F 3N 46A Hafnium Boride HfB2 P 4N7 123 Thallium Chloride TlCl P 3N ? 47 Hafnium Carbide HfC B 6N 125 Thulium Tm F 2N5 47A Hafnium Nitride HfN P 2N5 126 Tin Sn F 5N 47B Hafnium Oxide HfO2 P 3N ? 127 Tin Oxide SnO2 EM 2N5 48 Holmium Ho B 3N 127A Tin Sulfide SnS P 2N5 49 Indium In F 4N 127B Tin Selenide SnSe P 5N 50 Indium Arsenide InAs C ? 128 Titanium Ti F 2N5 50A Indium Antimonide InSb P 3N ? 128A Titanium Al Carbide Ti2AlC P 2N ? 51 Indium Phosphide InP C 5N ? 129 Titanium Carbide TiC HP 2N5 52 Indium Tin Oxide ITO P 4N 130 Titanium Diboride TiB2 HP 2N5 ? 10% In, Inhomogenous 131 Titanium Dioxide TiO2 EM 2N5 52A Indium Selenide In2Se3 P 4N 132 Titanium Nitride TiN P 4N5 52B Indium Sulfide In2S3 P 3N8 132A Titanium Oxide TiO HP 3N 53 Iridium Ir F 3N5 133 Titanium Silicide TiSi2 P 3N 54 Iron Fe P 4N 134 Tungsten W F 4N 54A Iron Carbide Fe3C F 3N 135 Tungsten Carbide WC HP 4N8 56 Iron Fluoride FeF3 P 3N 137 Tungsten Oxide WO3 P 2N+ 58 Iron Oxide FeO P 3N ? 138 Tungsten Silicide WSi2 P 2N5 59 Iron Oxide Fe2O3 P 5N 139 Tungsten Sulfide WS2 P 2N8 60 Iron Oxide Fe3O4 EM 5N 140 Vanadium V F 2N5 61 Iron Phosphide FeP EM 3N 141 Vanadium Carbide VC HP 4N ? 62 Iron Sulfide FeS2 P 3N ? 141A Vanadium Nitride VN HP 2N5 ? 63 Lead Pb P 4N8 142 Vanadium Oxide V2O5 P 4N ? 64 Lead Oxide PbO F 2N8 142A Ytterbium Yb F 3N 64A Lead Telluride PbTe P 5N 142B Ytterbium Oxide YB2O3 P 3N 65 Lead Sulfide PbS P Opt ? 143 Yttrium Y F * 3N 66 Lanthanum Hexaboride LaB6 P 3N5 ? 143A Yag YAlO C ? 66A Lanthanum Fluoride LaF3 P Opt 144 Yttrium Oxide Y2O3 P 4N 67 Lutetium Fluoride LuF3 P 3N 145 Zinc Zn F 3N8 68 Lithium Fluoride LiF P 4N 146 Zinc Oxide ZnO HP 3N 69 Magnesium Mg C * 3N 147 Zinc Selenide ZnSe C ? 70 Magnesium Fluoride MgF2 F 3N ? 148 Zinc Sulfide ZnS C ? 71 Magnesium Oxide MgO C 4N 149 Zirconium Zr F 3N5 72 Manganese Mn B 3N 150 Zirconium Carbide ZrC HP ? 73 Manganese Sulfide MnS B 2N5 150A Zirconium Nitride ZrN P 2N5 74 Manganese Oxide MnO2 P ? 151 Zirconium Oxide (Mineral) ZrO2 C 2N7 ? Mineral Formula (approximate) Mineral Formula (approximate) 152 Acanthite Ag2S 169A Diopside CaMgSi2O6 153 Albite NaAlSi3O8 170 Dolomite CaMg(CO3)2 154 Almandine Fe32+Al2(SiO4)3 170A Fayalite Fe22+SiO4 155 Andradite Ca3Fe23+(SiO4)3 171 Fluorapatite Ca5(PO4)3F 156 Anorthite CaAl2Si2O8 172 Forsterite Mg2SiO4 156A Augite (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6 173 Haematite Fe2O3 157 Baddeleyite ZRO2 (traces of Ti and Fe) 174 Hornblende Ca2(Mg,Fe2+)4Al(Si7Al)O22(OH,F)2 157A Barite BaSO4 (Amphibole) 158 Benitoite BaTiSi3O9 175 Kyanite Al2O3.SiO2 159 Biotite K(Mg,Fe2+)3(Al,Fe3+)Si3O10(OH,F)2 176 Magnetite Fe3O4 (black mica) 177 Orthoclase K2O.Al2O3.6SiO2 160 Bytownite (Na,Ca)Al(Al,Si)Si2O8 177A Pyrope Mg3Al2(SiO4)3 161 Calcium Carbonate CaCO3 178 Quartz SiO2 162 Cassiterite SnO2 179 Rutile TiO2 163 Chalcocite Cu2S 180 Sodalite Na4(AlCl)Al2(SiO4)3 164 Cinnabar HgS 180A Spessartine Mn2+3Al2(SiO4)3 165 Chrysoberyl BeAl2O4 181 Spinel MgAl2O4 166 Covellite CuS 181B Titanite CaTiSiO5 167 Cuprite Cu2O 182 Willemite Zn2SiO4 168 Diamond, same as #21 C (cleaved ~1mm) (Troosite) (additional cost) 183 Wollastonite CaSiO3 Note: electron probe compositions provided upon request or with standard. Some mineral standards have minor phases of other materials. SRM# National Institute of Standards & Technology (formerly NBS) Please see note below regarding alloys Glasses Code B2O3 Na2O MgO Al2O3 SiO2 Cl K2O CaO TiO2 V2O5 Cr2O3 MnO2 Fe2O3 ZrO2 PbO Bi2O3 BaO ZnO CoO CuO 184 612 14 2 72 12 +50 ppm of 51 other elements 185 93a 12.5 3.9 2.2 80.8 0.06 0.01 0.01 0.01 0.028 0.04 186 K252 40 5 35 10 5 5 187 K229 30 70 188 K326 30 2 30.1 29.9 8 189 K309 15 40 15 15 15 Ti Alloys Code Fe C Mn P S Si Cu Zn Pb Sn Ni Cr V Mo Ti As W Zr Nb Ta Al Co 190 654b 0.23 0.045 0.004 0.023 0.028 0.025 4.31 0.013 88.05 0.008 6.34 191 1128 0.134 0.011 3.04 2.96 15.13 75.64 3.06 Miscellaneous NIST Standards Code Fe C Mn P S Si Cu Zn Pb Sn Ni Cr V Mo Ti As W Zr Nb Ta Al Co 192 1104 0.088 0.005 61.33 35.31 2.77 0.43 0.07 193 1108 0.044 0.0025 64.9 34.4 0.06 0.39 0.033 194 1110 0.033 84.5 15.2 0.03 0.051 0.053 195 1230 Bal 0.044 0.64 0.023 0.0007 0.43 0.14 2.42 14.8 0.23 1.18 2.12 0.24 0.15 195A 1243 0.79 0.024 0.019 0.003 0.0018 0.018 0.007 58.78 19.2 0.12 4.25 3.06 0.053 1.23 12.46 195B 1297 Bal 0.066 7.11 0.038 0.0033 0.397 0.442 5.34 16.69 0.08 0.33 0.13 196 C2402 7.3 0.01 0.64 0.007 0.018 0.85 0.19 51.5 16.15 0.22 17.1 4.29 1.5 196A 2321 Solder : Sn 60% / Pb 40% 197 SRM-482 5 wires in one 3mm ø mount. Cu:Au (20:80, 40:60, 60:40, 80:20) + pure Cu (additional cost) 197A SRM-481 6 wires in one 3mm ø mount. Ag:Au (pure Ag, pure Au, 20:80, 40:60, 60:40, 80:20) (additional cost) 197B 871 Phosphor Bronze (CDA-521) (additional cost) Steels Code Fe C Mn P S Si Cu Zn Pb Sn Ni Cr V Mo Ti As W Zr Nb Ta Al Co 198 461 Bal 0.15 0.36 0.053 0.019 0.047 0.34 0.003 0.022 1.73 0.13 0.024 0.3 0.01 0.028 0.01 <.005 0.011 0.002 0.005 0.26 199 462 Bal 0.4 0.94 0.045 0.019 0.28 0.2 0.006 0.066 0.7 0.74 0.058 0.08 0.037 0.046 0.053 0.063 0.096 0.036 0.02 0.1 200 464 Bal 0.54 1.32 0.017 0.021 0.48 0.094 0.02 0.043 0.13 0.078 0.29 0.029 0.004 0.018 0.022 0.01 0.037 0.069 0.005 0.02 201 465 Bal 0.037 0.032 0.008 0.01 0.029 0.019 <.0005 0.001 0.026 0.004 0.002 0.005 0.2 0.01 0.001 0.002 0.001 0.001 0.19 0.08 202 466 Bal 0.065 0.11 0.012 0.009 0.025 0.033 0.001 0.005 0.051 0.011 0.007 0.011 0.057 0.014 0.006 <.005 0.005 0.002 0.01 0.04 203 467 Bal 0.11 0.23 0.003 0.009 0.26 0.067 0 0.1 0.088 0.036 0.041 0.021 0.26 0.14 0.2 0.094 0.29 0.23 0.16 0.07 204 468 Bal 0.26 0.47 0.023 0.02 0.075 0.26 <.0005 0.009 1.03 0.54 0.17 0.2 0.011 0.008 0.077 <.005 0.006 0.005 0.04 0.16 205 661 Bal 0.39 0.66 0.015 0.015 0.223 0.042 0.01 1.99 0.69 0.011 0.19 0.02 0.017 0.01 0.009 0.22 0.02 0.02 0.03 206 663 Bal 0.57 1.5 0.02 0.005 0.74 0.09 0.0022 0.32 1.31 0.31 0.3 0.05 0.01 0.04 0.05 0.049 0.24 0.05 207 664 Bal 0.87 0.25 0.01 0.025 0.066 0.25 0.024 0.14 0.06 0.1 0.49 0.23 0.05 0.1 0.069 0.15 0.11 0.15 208 665 Bal 0.008 0.0057 0.002 0.0059 0.008 0.0058 0.041 0.007 0.0006 0.005 0.0006 0.002 0.01 209 1761 Bal 1.03 0.68 0.043 0.033 0.19 210 1762 Bal 0.034 2.03 0.036 0.03 0.36 211 1763 Bal 0.2 1.59 0.012 0.022 0.65 212 1764 Bal 0.59 1.22 0.023 0.012 0.06 213 1765 Bal 0.006 0.14 0.007 0.004 0.005 214 1766 Bal 0.015 0.06 0.004 0.002 0.01 215 1767 Bal 0.051 0.02 0.005 0.009 0.02 216 1768 Bal 0.001 0.014 0.0013 0.0003 0.0006 0.0014 0.002 0.002 Alloys - Certified by a group of laboratories, NIST traceable. Analysis provided with each alloy purchased Stainless Steels + High Temp Low Alloy + Specialty Alloys Nickel/Cobalt Copper/Brass/Bronze 216B AISI 302 233 C-4140 242 Inco 600 249 CDA 360 217 AISI 303 234 C-4340 243 Inco 625 250 CDA 510 218 AISI 304 235 C-8620 244 Inco 718 251 CDA 655 219 AISI 316 236 Tool Steel A-6 245 Inco 800 252 CDA 857 220 AISI 321 237 Tool Steel D-2 246 Hastelloy C-22 221 AISI 410 238 Tool Steel H-13 247 Hastelloy C-276 222 AISI 440C 239 Tool Steel M-2 248 Hastelloy X 223 PH13-8MO 240 2Cr-1Mo (36a) 224 15-5 PH 241 9Cr-1Mo (38a) 225 17-4PH 241A 50 NIL 226 CARP 20CB3 241B 52100 227 Maraging 300 241C AISI 4820 228 HK-40 241D AISI 9310 Miscellaneous Standards 229 BPSG (not an NIST standard), 4% P, 3.3% B. 230 Al-Cu: NIST traceable standard for energy dispersive x-ray detector calibration (additional cost). 231 C-Cu-Ag: Standard for electron backscattering adjustment. Used for gun shot residue calibration 232 GSR- Gun shot residue: mixture of Ba, Sb, Pb particles in epoxy and carbon coated. Faraday Cup for beam current measurement, is available for all of the retainers and will take one of the spaces. PLEASE READ CAREFULLY! The metal alloys on this list cannot be assumed to be homogenous at the micrometer scale. If you intend to use ZAF corrections electron beam excited x-ray analysis (wavelength or energy dispersive), the sample volume must be homogenous within the electron excited volume. It is a misuse to use these metal alloys for bulk quantitative analyses. Nevertheless, they are useful for comparison purposes (in a least square sense) to compare against unknown materials. Every effort is made to insure that cutting, grinding, and polishing of the materials do not alter their composition.
SEM Low Magnification Calibration Disc
This comes mounted on a variety of standard mounts, or it can be mounted on a custom mount. The original scale was produced on a 15mm diameter glass disc as an inset on a rectangular microscope slide. The SEM Low‐magnification calibration disc is reproduced on a 1/8" nickel‐plated copper disc from this master. The scale is 1mm long with 100 markings, subdivided to 0.01mm and highlighted every fifth and tenth line. Selected intervals on the original stage micrometer have been measured using a traveling microscope. The movement of the microscope was measured by means of a helium‐neon laser interferometer. The wavelength of the laser has been determined by the reference of the International Krypton‐86 Standard. The distance between the lines was measured along the longitudinal axis of the scale. Number of IntervalLength of Interval at 20°C 0 to 10 0.0998mm 0 to 20 0.1997mm 0 to 30 0.2997mm 0 to 40 0.3998mm 0 to 50 0.4997mm 0 to 60 0.5596mm 0 to 70 0.6995mm 0 to 80 0.7994mm 0 to 90 0.8994mm 0 to 100 0.9994mm Accuracy: The uncertainty of each length interval quoted is estimated to be less than plus or minus 0.0005mm. Reference: These measurements were made at the National Physical Laboratory, Teddington, Middlesex, England. Test No. 08075 S/ML62‐199, dated July 6, 1979.
TEM Calibration Standard, Astigmatism Correction
This calibration specimen is a pure carbon film which contains holes of widely varying sizes across the entire grid. The holes have clean edges and show clearly defined Fresnel fringes when the objective lens is slightly under‐focused (a white fringe) or over‐focused (a black fringe). By observing the symmetry of the fringes while the objective lens is adjusted from under‐focus to over‐focus, the degree of astigmatism present can be determined. The astigmatism can then be corrected by adjusting the direction and strength of the objective lens stigmator. With a correctly adjusted lens, the black over‐focused fringe will appear in its entirety around the inside edge of a hole as the objective lens is adjusted from under‐focus to over‐focus. The fringe will be of a constant width. With an uncorrected objective lens, the black fringe appears at two opposite parts of the circumference of a hole first, then as the objective lens is further over‐focused; the remaining parts of the hole show a black fringe. However the fringe is not of constant width.
TEM Window Grids
Choosing the right TEM Window Grid, EMS76042 and EMS76043 Series Properties: Amorphous Silicon Porous Nanocrystalline Silicon Silicon Dioxide Silicon Nitride Standard Carbon Ultrathin Carbon Actual Thickness 5, 9, 15nm 15nm 20 & 40nm 5, 10, 20, 50nm 20-50nm ~10nm Image Quality Excellent Good Ok Good Ok Good Plasma Cleanable Yes Yes Yes Yes No No Elemental Analysis Background Si Only Si Only Si, O Si, N C, H C, H Thermal Stability ~600°C >1000°C >1000°C >1000°C ~400°C ~400°C Chemical Stability Avoid Strong Bases Avoid Strong Bases Good Excellent Good Good Tolerates High Beam Currents Excellent Excellent Ok Ok Excellent Excellent Potential Contamination Source None None None None Carbon Carbon Open Nanoscale Pores No Yes No No No No Background Featureless Nanocrystalline Featureless Featureless Featureless Featureless Membrane Window Strength - Differential Pressure Tolerance: Silicon Nitride All the membrane types and membrane area configurations have been robustness tested by application of differential pressure. In these tests, the membrane was oriented such that differential pressure forced the membrane against the chip frame. In the opposite orientation where the membrane would be delaminated from the chip frame, the pressure tolerance would be several times lower. All values below are the maximum tolerated differential pressure reported as mean ± standard deviation (n = 3), in units of PSI. Window Sizes: 9 Windows: (8) 100 x 100, (1) 100 x 350µm 9 Small Windows: (8) 50 x 50, (1) 50 x 350µm 2 Slots: (2) 50 x 1500µm Single Windows: (1) square window of x micron side-length Pure Silicon Thickness 5nm 9nm 15nm 30nm 35nm 9 Windows 3.90 ± 0.71 11.57 ± 0.26 9 Small Windows 2.30 ± 0.29 2 Slots 2.60 ± 0.99 2.53 ± 0.40 14.73 ± 2.61 Single 25 Micron 35.33 ± 0.78 Nanoporous - 9 Windows 16.47 ± 0.95 Nanoporous - Single 500 Micron 3.33 ± 0.17 Single Crystal - 9 Windows 34.03 ± 1.07 Silicon Nitride Thickness 5nm 10nm 20nm 50nm 9 Windows 6.13 ± 2.00 40+ 40+ 9 Small Windows 37.30 ± 3.08 9 Large Windows 11.57 ± 0.66 2 Slots 6.53 ± 0.24 Single 25 Micron 40+ Single 100 Micron 25.13 ± 4.45 Single 500 Micron 9.90 ± 0.36 13.37± 1.25 Single 1000 Micron 7.80 ± 0.29 Microporous - Single 500 Micron 5.37 ± 0.37 10.13 ± 0.52 Nanoporous - Single 500 Micron 5.33 ± 1.39 Silicon Dioxide Thickness 20nm 40nm 75nm 9 Windows 11.33 ± 0.37 12.73 ± 0.68 G-Flat™ Single 1000 Micron 2.93 ± 0.17 X-Ray Windows Thickness 50 nm 100 nm 200 nm 300 nm Single 500 Micron 20.47 ± 0.33 24.40 ± 0.99 Single 1000 Micron 9.67 ± 0.12 13.13 ± 0.09 Single 1500 Micron 6.97 ± 0.25 Single 2500 Micron 4.07 ± 0.09 G-Flat™ Single 500 Micron 5.60 ± 0.29 11.53 ± 0.12 G-Flat™ Single 1000 Micron 2.63 ± 0.05 TEM Grid Handling Instructions: TEM and X-Ray Windows are packaged in silicone gel-boxes with their suspended membrane films facing up (see cross-section). The suspended membrane side of TEM and X-Ray Windows should never be placed onto another surface in the opposite "face-down" orientation. TEM and X-Ray Windows are packaged in silicone gel-boxes with their suspended membrane films facing up (see cross-section). The suspended membrane side of TEM and X-Ray Windows should never be placed onto another surface in the opposite "face-down" orientation. We recommend handling TEM and X-Ray Windows from the sides of their frames using flat-sided, K6-style plastic or PTFE-coated tweezers. Do not directly touch the suspended membrane window. For best results when removing off the silicone gel-boxes, follow the technique shown in the figure (see below). Cleaning TEM and X-Ray Windows are made of ultrathin, silicon-based films that are very robust when dry, but care must be used when wet. For liquid cleaning, most organic solvents are compatible (e.g., isopropanol, acetone, toluene, etc.). Water or dilute solutions of HCl or H2SO4 can be used. Silicon nitride films can be cleaned in basic solutions, but dilute/weak bases can only be used for pure silicon and silicon dioxide films for short exposures (<10 seconds). When introducing TEM and X-Ray Windows into a solution, the chip should be held vertically with tweezers. The chip can then be moved up and down in the cleaning solution. To rinse, transfer to distilled/deionised water using the same method. Plasma Cleaning For plasma cleaning, we recommend using pure O2 if possible as Ar will degrade nanometer-thick films over time. Typical O2/Ar mixtures are acceptable. In general, silicon-based films can be cleaned for significantly longer (>60 seconds) than conventional carbon films, eliminating most organic contaminants. UV-ozone treatment is compatible as well. We recommend comparing a treated and untreated TEM or X-Ray Window when first characterizing cleaning protocols. If light microscope inspection reveals substantial change in color or wrinkling of the treated suspended membrane film, then conditions may be too aggressive and may have degraded the membrane film. We recommend following the system manufacturer's power settings. Note that pure silicon TEM Windows will oxidise in the presence of O2 at elevated temperatures and crystallise at >600°C. Sample Deposition When applying a liquid sample, we recommend placing a small drop of solution and wicking away the excess with a clean laboratory or lens tissue. The specimen should be allowed to dry in a clean environment as rapidly as possible to minimize contamination. If adhesion or dispersion is not as desired, pretreatment by O2 plasma or UV-ozone can be used to increase surface hydrophilicity. The use of typical MEMS processes for depositing other thin films is compatible with most TEM and X-Ray Windows. We recommend avoiding highly stressed films and/or high stress mis-matches that may occur during high-temperature depositions. Spin-coating other films is compatible as well, but we recommend an appropriate holder that avoids direct exposure of the suspended membrane to vacuum during spin-coating. Other Specifications Temperature and differential pressure tolerances are available by visiting our Technical Info page on the left navigation bar. Please contact us with any questions or concerns. Citations: Silicon Nitride Fabrication of a Lift-Out Grid with Electrical Contacts for Focused Ion Beam Preparation of Lamella for In Situ Transmission Electron Microscopy. Mecklenburg et al. (2013) Microscopy and Microanalysis. 19: 458-459. Cryo-SiN - A New Substrate to Monitor Viral Mechanisms. Tanner et al. (2013) Microscopy and Microanalysis. 19: 90-91. Three Dimensional Imaging of Dislocations in a Nanoparticle at Atomic Resolution Chen et al. (2013) Nature. 496(7433): 74-77. Blueshift of the surface plasmon resonance in silver nano particles: substrate effects. Raza et al. (2013) Opt Express. 21: 27344-27355 Grains and Grain Boundaries in Highly Crystalline Monolayer Molybdenum Disulphide Van der Zande et al. (2013) Nature Materials. 12: 554-561. Nanopatterning by ion implantation through nanoporous alumina masks Guan W, Ross I, Bhatta U, Ghatak J, Peng N, Inkson B, and Mobus G. (2013) Phys. Chem. Chem. Phys. 15: 4291-4296. Softening under membrane contact stress due to ultra-thin RU coatings on AU films Romasco-Tremper A, Mohney S, Andre K, Lin J, Muhlstein C. (2013) Materials Science and Engineering A. 565: 172-179. Twinning and Twisting of Tri- and Bilayer Graphene Brown, L, Hovden R, Huang P, Wojcik M, Muller DA. (2012) Nano Letters. 12(3): 1609-1615. Real-Time Single-Molecule Imaging of Quantum Interference Juffmann T, Milic A, Mullneritsch M, Asenbaum P, Tsukernik A, Tuxen J, Mayor M, Cheshnovsky O, Arndt M. (2012) Nature Nanotechnology. 7: 297-300. In Situ Analytical Electron Microscopy for Probing Nanoscale Electrochemistry Meng YS, McGilvray T, Yang MC, Gostovic D, Wang F, Zeng D, Zhu Y, and Graetz J. (2011) The Electrochemistry Society Interface. Fall, 49-52. MEMS Process Compatibility of Multiwall Carbon Nanotubes Carter et al. (2011) Vacuum Science & Technology B 29(6): 4-12. Graphene and boron nitride lateral heterostructures for atomically thin circuitry Levendorf et al. (2012) Nature. 488: 627-632. Tailoring Electrical Transport Across Grain Boundaries in Polycrystalline Graphene Tsen A, Brown L, Levendorf M, Ghahari F, Huang P, Havener R, Ruiz-Vargas C, Muller D, Kim P, and Park J. (2012) Science. 336: 1143-1146. Non-Porous Pure Silicon Electron Tomography at 2.4A Resolution Scott MC, Chen CC, Mecklenburg M, Zhu C, Xu R, Ercius P, Dahmen U, Regan BC, Miao J. (2012) Nature. 483: 444-447. Revealing Correlation of Valence State with Nanoporous Structure in Cobalt Catalyst Xin et al. (2012) ACS Nano. 6(5): 4241-4247. Direct Imaging and Chemical Analysis of Unstained DNA Origami Performed with a Transmission Electron Microscope Alloyeau D, Ding B, Ramasse Q, Kisielowski C, Lee Z, Jeon KJ. (2011) Chemical Communications. 47: 9375-9377. Porous Pure Silicon Quantitative Imaging of Ion Transport through Single Nanopores by High-Resolution Scanning Shen et al. (2012) J Am Chem Soc. 134(24):9856-9 Ion-Selective Permeability of an Ultrathin Nanoporous Silicon Membrane as Probed by Scanning Electrochemical Microscopy Using Micropipet-Supported ITIES Tips Ishimatsu R, Kim J, Jing P, Striemer CC, Fang DZ, Fauchet PM, McGrath JL, Amemiya S. (2010) Analytical Chemistry. 82(17): 7127-7134. Silicon Dioxide Silicon Nitride grids are compatible with correlative negative staining electron microscopy and tip-enhanced Raman spectroscopy for use in the detection of micro-organisms. Lausch et al. (2013) J Appl Microbiology. 116: 1521-1530. Controlling Dielectrics with the Electric Field of Light Schultze et al. (2013) Nature. 493: 75-78. Graphene Oxide Windows for In Situ Environmental Cell Photoelectron Spectroscopy Kolmakov A, Dikin DA, Cote LJ, Huang J, Abyaneh MK, Amati M, Gregoratti L, Günther S, Kiskinova M. (2011) Nature Nanotechnology. 6: 651-657. Irreversible Chemical Reactions Visualized in Space and Time with 4D Electron Microscopy Park ST, Flannigan DJ, Zewail AH. (2011) J Am Chem Soc. 130(6): 1730-1733. Metal-Catalyzed Growth of Semiconductor Nanostructures without Solubility and Diffusivity Constraints Wang Z, Gu L, Phillipp F, Wang JY, Jeurgens LP, Mittemeijer EJ. (2011) Advanced Materials. 23(7): 854-859. Biological Imaging with 4D Ultrafast Electron Microscopy Flannigan DJ, Barwick B, Zewail AH. (2010) Proc Natl Acad Sci. 107(22): 9933-9937.
Tungsten Filaments for Electron Microscopy
Tungsten hairpin filaments are the standard type filaments widely used in Scanning Electron Microscopes, Transmission Electron Microscopes and Microprobe systems. Tungsten filaments are also called cathodes or electron emitters or electron sources. The high quality filaments we offer are made to the original equipment manufacturer's specifications using special tools to guarantee the correct shape for the filaments and to generate the optimum electron beam. The filaments are annealed in vacuum, stress-free and precisely aligned before they are shipped. Please consult the list below for the correct type of filament for your SEM, TEM, or EPMA. The tungsten filaments are manufactured from high grade tungsten. Of all metals in pure form, tungsten has the highest melting point (3422°C), the lowest vapour pressure at temperatures above 1650°C and has the highest tensile strength. Tungsten also has the lowest coefficient of thermal expansion of any pure metal. This combination of properties makes tungsten the ideal material. Electron Microscopy Filaments Base TypeFilamentBase TypeFilament AEI ZEISS (DSM & TEM) LEO (1450 & TEM) TESCAN FEI/PHILIPS AMRAY (except 1200) JEOL K-type ISI/ABT/TOPCON 2-prong HITACHI S-type ISI/ABT/TOPCON 3-prong HITACHI in cartridge ETEC Electron Source Performance Comparison Emitter TypeThermionicThermionicSchottky FECold FE Cathode material W LaB6 ZrO/W (100) W(310) Operating temperature [K] 2,800 1,900 1,800 300 Cathode radius [nm] 60,000 10,000 < 1,000 < 100 Effective source radius [nm] 15,000 5,000 15 (*) 2.5(*) Emission current density [A/cm2] 3 30 5,300 17,000 Total emission current [µA] 200 80 200 5 Normalized brightness [A/cm2.sr.kV] 1.104 1.105 1.107 2.107 Maximum probe current [nA] 1000 1000 10 0.2 Energy spread @ cathode [eV] 0.59 0.40 0.31 0.26 Energy spread @ gun exit [eV] 1.5 - 2.5 1.3 - 2.5 0.35 - 0.7 0.3 - 0.7 Beam noise [%] 1 1 1 5 - 10 Emission current drift [%/h] 0.1 0.2 < 0.5 5 Operating vacuum hPa/mbar < 1.10-5 < 1.10-6 < 1.10-8 < 1.10-10 Typical Cathode life [h] 100 > 1000 > 5000 > 2000 Cathode regeneration not required not required not required every 6 to 8 hours Sensitivity to external influence minimal minimal low high * virtual source Dimensions for EM Filament Bases (for Tungsten/Lab6) Filaments Base TypeDiameter of Ceramic discDiameter of PinCentre Distance of Pin AEI 12.0mm 1.0mm 6.45mm FEI/PHILIPS 26.0mm 1.0mm 5.0mm JEOL K-type 28.0mm 1.2mm 8.0mm HITACHI S-type 9.8mm 1.2mm 2.7mm ZEISS (DSM & TEM) LEO (1450 & TEM) TESCAN 19.8mm 1.0mm 5.0mm AMRAY (except 1200) 26.1mm 1.0mm 5.0mm ISI/ABT/TOPCON 2 pins 23.3mm 1.2mm 11.9mm ISI/ABT/TOPCON 23.4mm 1.2mm 12.0mm