PILE-UP PHENOMENA IN SOLID-STATE DETECTION EFFECTS DUE TO SYNCHROTRON SOURCES

Pulsed sources of X-ray radiation, such as the storage rings associated with synchrotrons, give rise to sequences of sum-peaks in energy-dispersive spectra. These are due to pile-up processes occurring in the solid-state detection system (SSD). The phenomenon is most vivid when the storage ring is operated in single- or few-bunch mode, in which case the interbunch interval T(b) is up to an order of magnitude smaller than the pulse processing time T(p) of the spectroscopy amplifier. After a summary of basic aspects of SSD the theory of pile-up with synchrotron sources is presented. The effect is strongest when the spectrum contains only one or two strong features. The phenomenon is illustrated with a variety of examples. Experiments which simulate pulsed sources are briefly indicated. These permit evaluation of amplifier parameters that are needed if the theory is to be applied to the deconvolution of spectra in which pile-up rejection circuitry has been used,