From Keith:
The detector slit was 50 mm, at 750 mm from the source, and could be scanned across the beam. The monochromator has an output divergence of 5 arc seconds (2.5 x 10-5 radians) so will give a blurring of about another 20 mm, providing a spatial resolution overall of about 70 mm. The tube was a Siemens ceramic K FN Cu 2K, run at full power, with nominal focus 10 x 1 mm. It was run in vertical line mode with a takeoff angle of 6. The maximum count was 17,500 cps and lobes were observed at about 15 cps [as shown in figures he sent me]. The lobes were not symmetric [they span a detector Z range of -0.4 to +0.6mm with the central focal line from -0.15 to +0.15mm]. These lobes are lower than reported by Joerg Bergmann in www.bgmn.de/tubetails.html, but also the tube is a more modern design.
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1/sin(6 [deg take off]) X 0.5 mm [detector Z] = 4.78 mm: The origin of the X-rays of one lobe is ~5 mm from the focal line. While the count rate is low (for the narrow spectral window of the monochromator), this is not such good focusing. Somebody should invent a better mousetrap!
Regards,
Jim
James P.
Cline [EMAIL PROTECTED]
Ceramics
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National Institute of Standards and
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