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Gas measurements and CsI photocathode studies at WIS. Ilia Ravinovich November 2002 Weizmann Institute. Gas measurements at WIS. The system comprises a H20 FUV monochromator (100-500 nm), a Deuterium lamp (115-400 nm), PMT-1460 (115-320 nm) and LiF windows (cut-off 105 nm).
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Gas measurements and CsI photocathode studies at WIS Ilia RavinovichNovember 2002 Weizmann Institute
Gas measurements at WIS The system comprises a H20 FUV monochromator (100-500 nm), a Deuterium lamp (115-400 nm), PMT-1460 (115-320 nm) and LiF windows (cut-off 105 nm). The transmission is determined as CF4/Ar ratio normalized to Ar/Ar ratio. Beam splitter LiF Ar input LiF window Gas output MC Test cell D2 PMT-2 PMT-1 Ar output CF4 input CF4 output Detector
CsI photocathode studies at WIS The CsI photocathode (2500 A) was deposited on a polished stainless-steel substrate, pre-coated with a 1000 A thick Al layer. A positive voltage was applied to a mesh electrode placed at a distance at 3.5 mm. Exposure to air < 10 min. Beam splitter LiF CaF2 window CsI CF4 output MC D2 CF4 input +HV PMT-1 A Mesh The CsI photocathode was prepared on 15.11.2002 and since then is continuously operated in vacuum and in CF4 atmosphere. The photocurrents are stable and well reproduced after several cycles vacuum-CF4. The CsI photocathode is not destroyed by CF4!
Next steps at WIS The idea is to use a single monochromator both for transparency monitor and CsI absolute quantum efficiency measurements. Beam splitter LiF Gas output LiF window PMT-3 LiF window Rotate UV mirror (splitter) MC D2 PMT-2 +HV PMT-1 A A CF4 input CF4 output Mesh CsI Detector