(i)On the lower right-hand side of the page, select CURR (under rot center VOLT CURR) so that it becomes highlighted. This will cause the objective lens current to modulate (the inner STEP SIZE knob adjusts the amplitude of modulation). If the chosen feature shifts off center laterally, the beam is not aligned along the optical axis of the microscope and must be corrected.

(ii)Use the MULTIFUNCTION X/Y knobs to stabilize the feature at the center of the screen, eliminating all lateral movement. The feature should appear to be pulsating.

(iii)Press the ALGN button to return to the TEM BRIGHTFIELD page.

7.Centering the Objective Lens Aperture

For this procedure a specimen must be in place. Choose an area for which it is acceptable to sustain beam damage. With the OBJECTIVE APERTURE out, set the magnification to 5800x and overfocus the beam by turning the INTENSITY knob clockwise from crossover.

7.1Set the focus step size (inner STEP SIZE knob) to 5 and press the Zoom button to put the 'scope in diffraction mode.

7.2If necessary, adjust the CAMERA LENGTH to 620 mm using the MAG knob.

7.3Center the diffraction spot using the MULTIFUNCTION X/Y knobs.

7.4Using the focus (outer STEP SIZE) knob, refocus the beam to the smallest, brightest spot. It may also be necessary to adjust the INTENSITY knob.

7.5Insert the OBJECTIVE APERTURE by rotating the aperture displacement lever below it to the left.

7.6Apertures may be selected by rotating the largest knurled knob on the objective aperture assembly to any one of four numbered positions. (The APERTURE MEMO lists the diameters and

positions of the apertures currently installed in the 'scope. It may be accessed from the TEM BRIGHTFIELD page by clicking MODES and then CONFIGURATION.)

7.6.1Once the aperture has been selected, center it using both the smaller knurled knob in the series on the aperture assembly and the small knurled knob to the right. Remember not to manipulate the smallest, innermost knob, which is not knurled and will unscrew the aperture rod.

7.6.2Press Zoom to exit diffraction mode.

8.Objective Lens Astigmatism Correction

8.1Select an area that may be imaged at high magnification without harming any desirable portions of the specimen. Increase the magnification to 175,000x or higher and adjust the illlumination so that the substructure or background grain of the specimen may be observed easily. The INTENSITY will have to be modified and the beam will have to be recentered using the SHIFT X/Y knobs (Deflectors) as the magnification is increased. This latter function may alternatively be controlled using the RST button, on the panel to the left of the column.

8.2Set the focus step size to 2 and obtain a slightly underfocused image for maximum contrast.

8.3Press the STIG button to open the STIGMATOR CONTROL page. If it is not already highlighted, press the OBJ key on this page.

8.4Use the MULTIFUNCTION X/Y knobs, one at a time, to obtain the sharpest possible image of the grain substructure.

8.5Confirm that any astigmatism has been corrected by varying the focus (back and forth through focus, from underfocus to overfocus) and watching to see if a "streaking" pattern emerges and changes direction between under- and overfocus. If the astigmatism has been corrected, the specimen will vary only in focus, with no pattern evident. Repeat steps 4 and 5 until no pattern is apparent.

8.6Press the STIG button again to return to the TEM BRIGHTFIELD page.

9.Condense Lens Astigmatism Correction

This procedure is necessary if the beam spot is not a symmetric circle when the intensity knob is rotated.

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Philips CM-200 manual Centering the Objective Lens Aperture, Objective Lens Astigmatism Correction
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CM-200 specifications

The Philips CM-200 is a sophisticated electron microscope designed to facilitate high-resolution imaging and analysis of materials at the nanoscale. Renowned for its robust performance and versatility, the CM-200 is utilized extensively in both research and industrial applications, particularly in materials science, biology, and nanotechnology.

One of the key features of the CM-200 is its advanced electron optics, which utilizes a high-tension generator to produce a stable and finely focused electron beam. This enables researchers to achieve magnifications of up to 1,000,000 times, allowing for the visualization of structures that are mere nanometers in size. The high resolution is further complemented by a large depth of field, which provides unprecedented clarity and detail in imaging complex samples.

The CM-200 also incorporates a range of imaging modes, including bright field, dark field, and selected area diffraction imaging. These modes allow for a comprehensive analysis of the sample under various conditions, making it easier to identify structural features and materials' properties. Furthermore, the microscope is equipped with a state-of-the-art camera system, which captures high-quality images and facilitates real-time observation.

In terms of sample preparation, the CM-200 supports various techniques, including ultra-thin sectioning and cryo-preparation methods. This flexibility makes it suitable for analyzing a wide array of sample types, from biological tissues to advanced material composites. The ability to handle both conductive and non-conductive samples without significant alteration ensures that the integrity of the sample is maintained throughout the imaging process.

Moreover, the CM-200 is designed with ease of use in mind. Its intuitive interface and automated functions streamline operation, allowing users to focus on analysis rather than technical adjustments. This user-friendly design promotes efficiency and accessibility for both novice and experienced researchers.

In summary, the Philips CM-200 is a cutting-edge electron microscope that combines advanced technologies with user-centric features. Its high-resolution imaging capabilities, versatile imaging modes, and adaptability for various sample types make it an invaluable tool in scientific research and industrial applications. Researchers can rely on the CM-200 to provide detailed insights into the nanoscale world, driving advancements across multiple fields.
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