FPGA implementation of digital constant fraction algorithm with fractional delay for optimal time resolution

Authors: 
Jäger, Markus
Butz, Tilman
Year: 
2012
Language: 
English
Abstract in English: 
In a recent development of a fully digital spectrometer for time differential perturbed angular correlations a true constant fraction trigger (CFT) algorithm was implemented which, however, allowed for integer delays, i.e. integer multiples of the sampling interval, only. With a sampling rate of 1 GS/s and BaF2 scintillators this turned out to be insufficient. Here, we present an extension of the algorithm to fractional delays implemented in field programmable gate arrays (FPGAs). Furthermore, we derive a criterion for the delay for optimum timing based on the steepest slope of the CFT signal. Experimental data are given for LaBr3(Ce) scintillators and 511 keV - 511 keV prompt coincidences which corroborate the theoretical result.
Appeared / Erschienen in: 
Nuclear Instruments and Methods in Physics Research A
Pubdate / Erscheinungsdatum: 
2012-01-21
Pages / Seitenanzahl: 
4
URL: 
http://dx.doi.org/10.1016/j.nima.2012.01.022