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
-
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).
parameters:
-
timing resolution: 145 ps (FWHM 22Na)
-
coincidence counts rate: 100/s (1.5 MBq 22Na)
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