WG107
ISP, Novosibirsk, Russia
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
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WG107 |
First Measurements of Photoelectron Transverse Energy Distribution Curve using TESS | |
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| Electron injector brightness is limited by the transverse energy spread of the electrons emitted from a photocathode. Knowledge and understanding of the physical mechanisms underpinning this energy spread allows one to predict changes in the beam parameters. Ultimately, this information may help to optimize photocathode design, delivering improvements in photoinjector performance. In order to measure transverse photoelectron energy distribution curves (TEDC) ASTeC, in collaboration with ISP, have developed a Transverse Energy Spread Spectrometer (TESS). This equipment supports photocathode performance measurements both at room and LN2-temperature, under illumination from a range of fixed- and variable-wavelength light sources. TESS also includes a piezo-electric leak valve to allow controllable degradation of the photocathode whilst monitoring the energy spread of emitted electrons. In this work we discuss the principles of TEDC measurements on TESS, and present the first results for a GaAs-photocathode operated at room temperature. The measured TEDCs have exponential shape, and the mean transverse energies were equal to 45 meV for an illumination wavelength of 635 nm, and 102 meV when illuminated at 532 nm. | ||
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Slides WG107 [1.536 MB] | |