Electron Microscope Imaging Service—Philips 420 Transmission Microscope
Electron microscopes can excite electrons to form images that magnify micron and nanostructures up to 10 million times, providing amazing levels of fine magnification and allowing researchers to observe even individual atoms. CD BioSciences can provide innovative solutions for electron microscopy and microanalysis. We offer Philips 420 Transmission Microscope instruments that allow customers to combine high-resolution imaging with physical, elemental, chemical and electrical analysis to obtain usable data from the widest range of samples.
Name of the Instrument/Platform
Philips 420 Transmission Microscope
Introduction
1. Technical Specifications of the Philips 420 TEM.
2. Magnification: Range of 46× to 820,000× magnification
3. Accelerating voltage: Variable acceleration from 20KV to 120KV
4. Resolution: 0.34 nm point to point resolution
5. Stage: -45 to +45o Specimen Tilt
6. Image Capture: AMT 4000 digital imaging system with high resolution 2048 × 2048 pixel format.
7. Other:
1) LaB6 Filament for greater beam stability
2) EDAX Genesis system for materials characterization
3) Cold finger attachment
2.1 Specimen holders
The microscope is supplied with the Single Tilt specimen holder as standard. A range of holders supplying additional movements to the basic X, Y, Z and tilt of the goniometer stage, or special treatments, are available as options.
The following general instructions apply to all holders for the EM420 (holders for EM420 and CM10 are interchangeable):
i. When handling parts of specimen holders that enter the vacuum (beyond the sealing 'O'- ring), always use nylon or similar gloves. NO GREASE
ii. The specimen, spacing rings, and clamping devices should only be manipulated using pointed tweezers and special tools provided. These should be maintained in a clean condition.
iii. Before use check the holder tip with a magnifying glass to ensure that it is clean and dry. The critical bearing surface is made of sapphire. Check also that the seating of the specimen carrier is clean and does not contain residues. Clean with compressed air cans.
iv. The O-ring on the rod should be checked for possible dirt and excessive quantities of grease, although it must not be completely dry.
v. When a specimen holder is not in use, store it in its box. Keep the specimen support clean and also store it in the box when not in use. O -Ring
2.2 Mounting a specimen in the single tilt holder
i. Check that the tip of the holder and the clamping device are clean and dry
ii. Rest the holder on its support with the spring clamp horizontal, ensuring that the tip is properly supported by the recess in the block.
iii. Lift the clamp to its fullest extent using the tool, which fits into a hole into the front of the clamp.
iv. Carefully place the specimen (if a grid, with the specimen uppermost) in the carrier (14) . View with a magnifying glass to make sure that it is correctly loaded.
v. Carefully lower the clamp onto the specimen (or grid) making sure that the specimen remains correctly in position.
CAUTION: This procedure must be carefully controlled, otherwise the clamp can be damaged, resulting in specimen instability.
2.3 Removing a specimen from the single tilt holder
i. Rest the specimen holder on its support (as described in section 2.2 above).
ii. Lift the clamping device (as described in section 2.2) .
iii. Remove the specimen by inverting the holder over a Petri dish or filter paper.
2.4 Beam astigmatism correction Everything acting upon the beam in the illuminating system can contribute to its astigmatism. Thus, whenever the condition of any component in the system is charged (e.g. spot size, or aperture sizes) the beam astigmatism may change and therefore need to be corrected. The alignment of the condenser stigmator is carried out during installation and does not need subsequent realigning.
Beam astigmatism correction is carried out as follows:
i. Insert a specimen (see section 2.2) .
ii. Set Magnification control (9) to position 25, or higher > 23000×.
iii. Adjust specimen height (see section 3. 10.3 in instruction manual, pg. # 151) .
iv. Focus the image (control 15a, 15b).
v. Remove the specimen from the beam.
vi. Select maximum beam intensity (intensity control 5a close to fully counter-clockwise).
vii. Undersaturate the filament (control 2a) until a filament image is obtained. If necessary, adjust Gun tilt controls (16) until a symmetrical filament image is obtained.
viii. If necessary, readjust the intensity until the structure of the filament is visible in the central area of the image. This will usually be sharp in two perpendicular directions for different settings of the intensity controls (5a, b).
ix. Adjust the Condenser stigmator controls (17) until filament structure is sharply focused in all directions for one setting of the intensity control.
x. Saturate the filament (control 2a).
*Once filament saturated for one emission current, through coupling it is saturated at all emission current settings.
2.5 EDAX Operations on the Philips
i. Use the low-background single-tilt specimen holder
ii. Find an area of interest on your sample.
iii. Remove the objective aperture.
iv. Lower spot size in necessary
v. Insert the detector via the computer control.
vi. The microscope is now ready for EDAX acquisition.
vii. Adjust the TEM Spot Size to a smaller spot if dead-time is over 40%, use a larger spot size if it is less than 10%. The detector will automatically withdrawal if the counts are too high.
viii. When you wish to observe the sample remove the detector and insert the objective aperture.
Summary
The Philips 420 is equipped with a LaB6 filament and has an accelerating voltages up to 120Kv for enhanced resolution, making it especially suitable for users working with nanomaterials. A new AMT 4000 camera has recently been added to the system to provide high resolution digital imaging. The instrument is also equipped with an EDAX Genesis X-ray microanalysis system for materials elemental characterization. This instrument is ideal for both biological and materials research.
CD BioSciences provides Philips 420 Transmission Microscope-based electron microscopy imaging services to our clients. If you are interested, please feel free to contact us.
For research use only, not intended
for any clinical use.
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