Changes in Spectral Sensitivity of Multiplier Phototubes Resulting from Changes in Temperature

Abstract

The change in cathode spectral sensitivity of Westinghouse WX 4582 (S-11) and RCA 1P21(S-4) multiplier phototubes was measured across the visible spectrum, i.e., from 400 nm to 700 nm, for various temperature changes, both increases and decreases. Two methods were used for these measurements, viz., an adaptation of the Hardy spectrophotometer and the use of an environmental chamber. A decrease in temperature usually caused an increase in sensitivity in the short wavelength part of the spectrum and a decrease (as much as 90% at 700 nm) in the long wavelength part of the spectrum, with the crossover point (no appreciable change of sensitivity with change of temperature) at about 590 nm. An increase in temperature was accompanied by a reversal of spectral sensitivity changes, i.e., a decrease in the short wavelength part of spectrum and an increase in the long wavelength part of the spectrum. The change in cathode sensitivity varied with different types of phototubes and with phototubes of the same type.

Optimization of parameters in photon counting experiments

“…As expected Rd decreases with decreasing temperatures, but the sensitivity of the PMT also decreased. Changes in cathode sensitivity with temperature are well known, and PMTs with CsSb photocathodes, e.g., the 1P28, show decreased sensitivity with decreasing temperature (6,9,18,19). The ultimate SNR obtained at -23.0 °C was within a factor of two of that obtained at room temperature.…”

Stream combinator and aqueous standards in flame atomic absorption spectrophotometric analysis of organic base samples

“…However, the detection limit of a spectrometric analysis would be improved by a factor of 2-8 by cooling these tubes if dark current noise was the limiting factor at room temperature. Excessively low temperatures can reduce the cathodic responsivity of the tube (18,27).…”

Airborne Measurements of Optical Atmospheric Properties at Night

“…The characteristics of all photocathodes are temperature dependent in a comrplex inannei (Murray andManning, 1960, BoilIeau andMiller, 1967). The effect is not only a simple change of sensitivity with temn-- ¶perature;, it is also a func*ton of wavelength For example, lowering the temperature of the cathode may increase the sensitivity by 101. in the short wavelength part of the visible spectrum, while the sensitivity in the long wavelength part of the spectrum is decreased by 50o It is essential,, therefore, that the phototube cathode be mainrtai ned at a constant temperature.…”

“…The spectral sensitivity of multiplier phototube cathodes varies as a function of their temperature (Murray andManning, 1960, andBoileau andMiller, 1967). This variation is not only a simple change of sensitivity with temperature: it is also a function of wavelength.…”