A LARGE-AREA VUV PHOTOSENSOR WITH HIGH-GAIN BY MEANS OF PHOTOELECTRONACCELERATION AND CONCENTRATION

We report the results of the development of a new photosensor with lar ge area and high gain. The photoelectrons from a 48 mm diameter CsI ph otocathode are accelerated with high voltage and electrostatically con centrated rather than imaged onto the surface of an 8 mm diameter semi conductor detector. The amplitude of the photoelectron signals initiat ed by a pulsed xenon lamp of constant intensity and high stability (in stability < l%) is approximately linear with the accelerating voltage in the 10 to 20 kV region. Non uniformity of the signal amplitude over 70% of the photocathode area is below 6%.