Highly segmented detector arrays for studying the resonant decay of unstable nuclei

Abstract

Resonant spectroscopy of short-lived nuclei produced in nucleus–nucleus collisions can provide information on the nature of the nuclear surface and the formation of clusters. Detection of these resonant decays requires detector arrays with good energy and angular resolution. This newest generation of detector array is typically comprised of silicon strip detectors with several hundred to several thousand independent segments. As a key issue of such arrays is the processing of their signals, we report on the development of a non-ASIC system designed to simplify the analog processing and readout from a highly segmented silicon detector array. The non-ASIC system called MASE (multiplexed analog shaper electronics) focuses on providing good energy resolution and adequate timing information for up to 4096 channels. It consists of 16-channel boards which can be either used independently or as part of a larger system. The analog portion of each channel has low and high gain shapers with associated leading edge discriminators and peak hold circuits. The logic for readout of the analog signals is performed by two FPGA chips located on each board. Readout of MASE channels is multiplexed. Logical signals are transferred via LVDS while the analog signals are sequenced into a multisampling ADC. Signals are also multiplexed for inspection purposes. Shaper gains and discriminator thresholds are adjustable through DACs via a USB interface.