Tables for
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C, ch. 7.1, pp. 628-629

Section Current ionization PSD's

U. W. Arndtb Current ionization PSD's

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For the very highest counting rates, it is necessary to abandon all methods in which individual X-ray photons are counted and instead to measure the ionization current produced by the incident X-rays on either cathode or anode. Fig.[link] shows the principles of a cathode read-out linear PSD. The cathode is divided into strips, each of which is connected to a capacitor and to an input terminal of a CMOS analogue multiplexer. The charge accumulated on each capacitor in a given time period is transferred to a charge-sensitive amplifier when the associated channel is selected by an addressing signal. The output voltage of the amplifier is digitized by means of an analogue-to-digital converter. The complete pattern is scanned by incrementing the addresses sequentially: The resolution is that of the strip spacing (∼0.5 mm) and the principle can be extended to two dimensions (Hasegawa, Mochiki & Sekiguchi, 1981[link]; Mochiki, Hasegawa, Sekiguchi & Yoshioka, 1981[link]; Mochiki, 1984[link]; Mochiki & Hasegawa, 1985[link]). Global count rates in excess of 109 s−1 are possible with this method. Lewis (1994[link]) has published a comprehensive survey of the present status and the future potentialities of gas-filled position-sensitive detectors.


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Integrating LPSD. From Mochiki (1984[link]); courtesy of K. Mochiki.


Hasegawa, K., Mochiki, K. & Sekiguchi, A. (1981). Integral type position-sensitive X-ray detector for high-flux diffuse scattering applications. IEEE Trans. Nucl. Sci. NS-28, 3660–3664.
Lewis, R. (1994). Multiwire gas proportional counters: decrepit antiques or classic performers? J. Synchrotron Rad. 1, 43–53.
Mochiki, K. (1984). Integral type position-sensitive proportional chamber. Dissertation, Faculty of Engineering, University of Tokyo, Japan.
Mochiki, K. & Hasegawa, K. (1985). Charge-integrating type position-sensitive proportional chamber of time-resolved measurements using intense X-ray sources. Nucl. Instrum. Methods, A234, 593–601.
Mochiki, K., Hasegawa, K., Sekiguchi, A. A. & Yoshioka, Y. (1981). Integral type position-sensitive proportional chamber with multiplexer read-out system for X-ray diffraction experiments. Adv. X-ray Anal. 24, 155–159.

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