Measurement of the dynamic response of low-gain solid-state photodetector under weak pulse illumination

This paper presents the development of a Tunable Light Pulse Generator built to measure the quantum efficiency of photodetectors under continuous or pulsed (20ns FWHM) illumination as a function of wavelength in the Visible–UV region. For this purpose, a miniature Hamamatsu R5600U-04 PMT with low cathode resistivity can be used as reference detector. Dedicated electronics was developed in order to measure simultaneously the cathode and anode currents. This should allow to determine precisely the gain as a function of the high voltage applied to the PMT. Preliminary measurements using the TLPG do not demonstrate significant differences between the dynamic (∼10000 photons) and DC responses of PIN photodiodes down to 300nm.