Optimization pathways for a four-tube digital positron lifetime spectrometer
Abstract The count rate and timing resolution are paramount in positron annihilation lifetime spectrometer (PALS), dictating their ability to discern fine-scale material properties. We introduce a compact 4-tube PALS configuration that enhances the standard measurement process by capturing 12 spectra simultaneously, reducing measurement times and enabling the observation of rapid material dynamics such as fast kinetics of precipitations in Al-alloys. Our approach allows for the effective decomposition of 12 spectra collected within 2 minutes with a time resolution of 141 ps and a count rate of 2000 cps. This improved counting rate of the 4-tube PALS system is further complemented by comprehensive tests, aiming at optimizing both digitizer-related and scintillator/photomultiplier tube (PMT) parameters, offering a strategic contribution to improving PALS capabilities for the positron community. Within these tests, we employed, in addition to the 4-tube setup, a 2-tube dPALS, ...