ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
With recent improvements in synchrotron sources and x-ray optics great pressures have been placed on detector systems to produce higher count rates and better resolutions. Present high performance 13 element germanium detector systems can give reasonable count rates with good resolution (∼104–105 kHz per channel and ∼250 eV FWHM at Fe55 with 0.5 μs shaping time). However, these systems are restricted by limitations in both the detector and in the analog pulse processing after the detector. With respect to the detector, increasing the number of channels without degrading the energy resolution is a great challenge due to increased crosstalk and capacitance. The analog pulse processing electronics are significantly limited by the dead time introduced by the shaping amplifier. This dead time causes pulse pileup at higher rates which leads to nonlinearity and poor resolution. This paper describes the XSPRESS system which has been developed at Daresbury Laboratory for the new Wiggler II beamline 16. This system overcomes previous limits in both signal processing and detector fabrication to give great improvements in system performance. The signal processing electronics departs from standard analog processing techniques and employs sophisticated adaptive digital signal processing hardware to reduce the dead time associated with each event to a minimum. This VME based technology allows us to vastly increase the count rate for each channel yet still retain the ability to gain very good resolution. The detector has been developed through a collaborative agreement with EG&G ORTEC and packs an unprecedented 30 germanium crystals into an extremely small area while still retaining the energy resolution of smaller arrays. This system has increased the throughput rate by an order of magnitude per channel and when all channels are implemented, an increase of at least two orders of magnitude for the whole array should be seen. Data have been taken using this system on the SRS at Daresbury Laboratory and these results will be given along with a detailed explanation of the operation of this system. © 1995 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1145672
