Side-on PMT
Photon Counting Head H8259 Series

The H8259 series are photon counting head devices containing a 28 mm (1- 1/8") diameter side-on photomultiplier tube, high-speed photon counting circuit, and high-voltage power supply circuit. Three types of photomultiplier tubes are provided as standard lineups to meet various needs for spectral response range. The photomultiplier tube sensitive in the near IR region usually has a large dark count due to thermal noise but high S/N measurements can be obtained since a low-noise photomultiplier tube is selected. The high voltage supply for photomultiplier tube and the discrimination level are preset to optimum levels, allowing photon counting measurement by just connecting a +5 V supply. An electronic gate circuit (shutter circuit) is also included to eliminate extraneous light such as excitation light from the measurement.