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Persistent URL http://purl.org/net/epubs/work/10855956
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Record Id 10855956
Title The commissioning of TESS: An experimental facility for measuring the electron energy distribution from photocathodes
Abstract ASTeC have developed an instrument to measure the transverse energy (etr) of electrons emitted from photocathode sources. The instrument (‘TESS’ for transverse energy spread spectrometer) is connected to our GaAs photocathode preparation facility (PPF) which is capable of producing photocathodes with quantum efficiencies (Q.E.) up to 20% at 635 nm [1, 2]. TESS is currently being used to study the emission properties of these photocathodes. The methodology is based on extracting a fA–scale electron beam from a small area of a photocathode source, and allowing it to expand under the influence of its transverse energy component while in flight between the electron source and a detector. Images of the electron emission footprint are analysed to measure the transverse energy distribution curve (TEDC), and the mean transverse energy extracted (MTE) from this. TESS is compatible with a number of different light sources, so can support measurements on various photocathode materials from the metal and semiconductor families. The system includes a piezo–electric leak valve allowing precision gas dosing to control the degradation state of the photocathode, and therefore its Q.E.. The system also supports cathode cooling to LN2 temperature at 77 K. The system has been commissioned recently, in collaboration with the Institute of Semiconductor Physics (ISP) at Novosibirsk. We present this TESS commissioning data for photoelectron emission from a GaAs photocathode.
Organisation ASTeC , ASTeC-AP , ASTeC-VS , STFC
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Language English (EN)
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Paper In Conference Proceedings In 35th International Free Electron Laser Conference (FEL '13), Manhattan, New York, U.S.A., August 26-30, 2013, CI Preprints (2013). 2013 Proc. FEL '1…ead measurements.pdf 2013