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The Calibrate menu (formerly accessed via a mouse button) is now accessed from the opening screen. Type 'CalMu', and the calibration subroutine will run normally. This procedure is for DRV-2000 Revision A and B hardware. If you have the original revision of the DRV-2000 (purchased from 1990 to 1994), contact us for upgrade information. Email Here.
1. Coarse aspect ratio and mag adjustment. 2. Fine aspect ratio adjustment. 3. Magnification calibration. Start with a sample of known aspect ratio and size. A magnification standard can be used. An aperture or grid (of known size) works well, but your lab may have trace ability requirements. Get an image of the standard on the SEM such that the standard takes up 75% or better of the useable area of the SEM's CRT. You may wish to shoot a Polaroid for reference. Proceed into a rapid scanning mode of the DRV-2000. Typically the mini-scan mode. If you have the revision B board, use the "rapid scanning" mode available by pressing the F key from the opening menu of DIGISEM. Compare the image on the PC to that of the Polaroid. At this time we are only getting the area scanned and the aspect ratio roughly calibrated. This is accomplished by turning the X and Y scan trimpots located along the long edge of the board. On most PC's the adjusting screws will face you. Turning the adjustments causes the scanned area to be enlarges, thus making the image on the PC monitor smaller. Under scan the SEM, that is, intentionally make the image seen on the PC "a bit" larger than it appears on the reference Polaroid. Don't try to make the aspect ratio perfect yet. When the image in rapid scan appeared to be the same as that of the reference Polaroid (but at 10-20% higher mag), the coarse calibration is complete. The MEASURE routine is used for fine calibration of the aspect ratio. Merely compare measurements taken in the X and Y axis, and adjust either the X or Y axis via the scan trimpots used previously. Make a small adjustment (say a half turn) at first, recollect the image, and re-measure. Repeat this procedure until the X vs. Y measurement is within 1% or better. Note that the actual measurements are inaccurate until the magnification is calibrated. It is only important that X and Y be the same. After the aspect ratio is accurate, the magnification is calibrated. This is done by entering 'CalMu' from opening menu. That is, press the keys C-a-l-M-u. The following menu will pop up:
It is essential that the magnification be entered accurately from the SEM. After the magnification is entered, press the 'Enter' key, and the Calibrate dialog box will display an additional field.
'STD length' refers simply to the length of the standard, in microns. A reference image will be scanned onto the PC monitor. You will be telling the PC what the size of the standard is by placing a cursor at each end of the image of the standard. Simply place the mouse at the left edge of the standard and left click it. Then drag the mouse horizontally to the right edge of the standard. If you are not horizontal the program will generate a tone indicating the amount of error from horizontal. When you are perfectly horizontally aligned with the first cursor there will be no tone. Click the mouse again. The system is now calibrated. The calibration number will not be stored until you close the program. If you made an error in calibrating, simply repeat it. The latest calibration will be saved. Calibration should be complete. Proceed back
to the Installation menu. |
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DIGISEMTM and
DRV-2000TM are a registered
trademarks of ELMDAS Company.
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