Question #d548d
1 Answer
Apr 20, 2016
The normal response of a photomultiplier's dark current is to decrease as temperature decreases.
Explanation:
The electron flow in the absence of light in a photomultiplier tube (PMT) is the source of what is usually called dark current. Since the detector surface of PMTs is composed of a low work-function material, the surface exhibits thermionic emission even at room temperature. This source of dark current is temperature dependent, and decreases as temperature decreases. At some point, when the temperature is low, the dark current is dominated by other sources of leakage.
Typical dark current vs. temperature curves are shown in the following graph:
