The origins of afterpulses in photomultipliers

Abstract

The chemical nature and physical origin of the afterpulses found in RCA 8850 and 8852 photomultipliers have been investigated. It has been confirmed that the increase in the number of afterpulses with time was the result of diffusion of helium through the tube envelope. It has also been shown that afterpulses may originate throughout the photomultiplier, and the factors which influence their formation are discussed.

Time-of-flight of He ions from laser-induced processes in ultra-dense deuterium D(0)

“…One possible problem in this type of experiment is the existence of so called afterpulses in the PMTs, due to ions formed in the residual gas in the PMT by an intense electron pulse passing through the PMT [33,34]. The afterpulse spectrum is often found in the range above a few hundred ns.…”

“…To complete the discussion about afterpulses [33,34] in the PMTs, examples of suspected afterpulse spectra are shown in Fig. 6 with a different setup.…”

FLIM and FCS detection in laser‐scanning microscopes: Increased efficiency by GaAsP hybrid detectors

“…More important is afterpulsing. In photomultipliers, afterpulsing is caused by ionisation of rest gas molecules (Coates, 1973). In singlephoton avalanche photodiodes (SPADs) it is caused by trapped carriers of previous avalanche breakdowns.…”

Characterization of SPAD Array for Multifocal High-Content Screening Applications

“…The result is very similar to dark counts, except the number of erroneous counts are proportional to the collection rate. Afterpulsing is different in PMTs, since it results in a set of afterpulses at discrete time delays from the original pulse, where the time delays correspond to different ionized residual gases in the vacuum tube [40,41]. By comparison, SPAD afterpulsing is much more uniform across the histogram and, therefore, can be removed as a uniform background subtraction [42].…”