Speed properties of the hybrid photodiode tube

The Hybrid PhotoDiode (HPD) tube, a non-multiplicative photon detector with a gain of a few thousand, has been proposed in recent years for the replacement of photomultiplier tubes. Recent developments of the silicon chip (the active element in this detector) allowed it to perform with sub-nanosecond rise times for electrostatically focused versions and between less than one and a few ns rise times (depending on the working conditions and on the chipʹs active surface) for proximity focused, magnetic field insensitive models. The negligible electron time of flight fluctuations and of photoelectron to photoelectron pulse height variations, make the HPD an ideal tool for photon timing. Timing precision below 100 ps was easily achieved.