The study of linearity and detection efficiency for 20″ photomultiplier tube

BackgroundThe linearity and photon detection efficiency (PDE) are important parameters of photomultiplier tube (PMT), which need to be precisely measured with suitable techniques.
PurposeTo search good methods for linearity and PDE study of newly developed 20-inch PMT.
MethodsIn this paper, we setup a testing system to use the average photoelectrons (P.E.) in pulse mode for linearity measurement with the result corrected for strong light. For the PDE measurement, we developed a relative method with a reference PMT whose efficiency is known to compare the measured PDE with both average charge and hit numbers.
ResultsThe measurements of PMT shows only 5% nonlinearity within 1000 P.E. and good PDE, the result of linearity’s corrected definition is closer to the real status of PMT.
ConclusionsThe results show good charge and linearity response for newly developed 20-inch MCP PMT and dynode PMT. The testing techniques discussed in this paper are suitable for the study of PDE and linearity.