Positron Annihilation Group, Charles University in Prague
DLTP MFF UK
V Holešovičkách 2, 180 00 Praha 8
Tel.: +420 221 912 788, Fax.: +420 221 912 567,Jakub.Cizek@mff.cuni.cz CZ
New:
PLRF 19 code for fitting of positron lifetime - binaries are available for download.Digital positron-lifetime spectrometer
Detector part of spectrometer
- fast-fast setup
- detectors: Hamamatsu H3378 photomultipliers equipped with BaF2 scintillators
- digitizer: Detector signals are sampled in the real time using two ultra-fast digitizers Acqiris DC211 (8-bit, sampling frequency 4 GHz)
Digitizers
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software: Digitized pulses are analyzed off-line
using integral constant fraction technique, described here:
- F. Bečvář, "Methodology of positron lifetime spectroscopy: Present status and perspectives", Nuclear Instruments and Methods in Physics B 261, 871-874 (2007).
- timing resolution: 145 ps (FWHM 22Na)
- coincidence counts rate: 100/s (1.5 MBq 22Na)
parameters:
Full decsription of the digital spectrometer can be found in the following papers:
- F. Bečvář, J. Čížek, I. Procházka, "High-resolution positron lifetime measurement using ultra fast digitizers Acqiris DC211", Applied Surface Science 255, 111-114 (2008).
- F. Bečvář, J. Čížek, I. Procházka, "Performance of a High-Resolution Digital Positron-Lifetime Spectrometer", Acta Physica Polonica A 113, 1279-1284 (2008).
- F. Bečvář, J. Čížek, I. Procházka, J. Janotová, "The asset of ultra-fast digitizers for positron-lifetime spectroscopy", Nuclear Instruments and Methods in Physics Research A 539, 372-385 (2005).
Digital positron spectrometer with cryostat for measurement at low temperatures