Photomultipliers are fast, sensitive and low noise light detectors which operate across the ultraviolet–optical–near infra red region of the electromagnetic spectrum. Sensitivity is determined by the composition of the photocathode layer in which incident photons excite photoelectrons and the thickness of this layer. Incident light is partially reflected from and partially transmitted through t...

A new photocathode called a ‘‘photosensitive field emitter’’ has been proposed, and a prototype was fabricated. This new Ž . photocathode was realized using a gated Si field emitter tip and an hydrogenated amorphous Si a-Si:H p–i–n photodiode. The emission current from the photocathode is proportional to the illumination intensity, and detectable maximum of the illumination intensity was about ...

A spectral response setup was commissioned at the Cs-K-Sb photocathode preparation and analysis system, developed for the bERLinPro project. The setup is designed to measure the spectral quantum efficiency from 370 to 700 nm, to monitor the photocurrent during the photocathode growth process and the photocathode lifetime at 515 nm.

The Photocathode Electron Gun (PEG) at SLAC is required to produce bunch intensities of up to 10 electrons within 2 ns (8 Amps). Operation of PEG has demonstrated a ‘Charge Limit’ phenomenon, whereby the charge that can be extracted from the gun with an intense laser beam saturates at significantly less than 10 electrons (the expected ‘Space Charge Limited’ charge) when the photocathode Quantum...

The Stanford Linear Collider Injector requires two 2 ns pulses of 4.5-5.5 x 1010 electrons, separated by 61 ns at 120 hz, from its source. Since 1992, these currents have been provided by a polarized electron source based on GaAs photocathodes. A beam polarization of 76 + 4% has been measured at the end of the 50 GeV linac. At low photocathode quantum efficiencies, and for excitation near thres...

1098-4402= Strained-layer GaAs and strained-superlattice GaAs photocathodes are used at Jefferson Laboratory to create high average current beams of highly spin-polarized electrons. High electron yield, or quantum efficiency (QE), is obtained only when the photocathode surface is atomically clean. For years, exposure to atomic hydrogen or deuterium has been the photocathode cleaning technique e...

A CuGaO2 p-type semiconductor electrode was successfully employed for constructing a new hybrid photocathode with a Ru(II)–Re(I) supramolecular photocatalyst (RuRe/CuGaO2). The RuRe/CuGaO2 photocathode displayed photoelectrochemical activity for the conversion of CO2 to CO in an aqueous electrolyte solution with a positive onset potential of +0.3 V vs. Ag/AgCl, which is 0.4 V more positive in c...

This work extends past research at Jefferson Lab aimed at better appreciating the mechanisms that limit photocathode operational lifetime at high current (> 1 mA). Specifically, the performance of an improved 100 kV DC high voltage load locked photogun will be described. Although difficult to measure directly, we believe the new gun has better vacuum conditions compared to the original gun, as ...

Preliminary results of a photon detector combining a Micromegas like multiplier coated with a UV-sensitive CsI photocathode are described. The multiplier is made in the CMOS compatible InGrid technology, which allows to post-process it directly on the surface of an imaging IC. This method is aimed at building light-sensitive imaging detectors where all elements are monolithically integrated. We...