The Becker and Hickl PMC-150 is a cooled PMT module for TCSPC applications. It contains a fast miniature PMT along with a Peltier cooler, a high voltage generator, a GHz pulse amplifier and a current sensing circuit. Due to the high gain and bandwidth of the device a single photon yields an output pulse with an amplitude in the range of 100 to 200 mV and a pulse width of 1.5 ns. Due to the high gain and the efficient shielding noise pickup is minimised. Therefore the PMC-150 yields high time resolution and high counting efficiency.
Fig 1: IRF for 1 mm spot and for full cathode illuminated.
Fig 2: Variation of IRF with position on photocathode.
The TCSPC instrument response function (IRF) has a width of less than 130 ps FWHM. The IRF shift with the position at the photocathide is less than 50 ps. Overload conditions are detected by sensing the PMT output current. Overload is indicated by an LED, an acoustic signal, and a logical overload signal. The PMC 150 is operated by the bh DCC-100 detector controller card. The DCC delivers the operating voltage for the PMT, the current for the Peltier cooler, controls the detector gain, and shuts down the PMT in case of overload. Compared to its predecessor, the PMC-100, the PMC-150 has a shorter IRF width and a better IRF uniformity over the active area.