| Paper | Title | Page |
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| WEPNEC17 | Developments in Photocathode R&D at STFC Daresbury Laboratory: New Transverse Energy Spread Measurements and the Development of a Multi-Alkali Photocathode Preparation Facility | 103 |
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Photocathode R&D activity within ASTeC is focussed on further development of the tools required for the preparation and characterisation of high performance photocathodes for X-FELs. Our Transverse Energy Spread Spectrometer (TESS)* experimental facility can be used with III-V semiconductor, multi-alkali and metal photocathodes to measure transverse and longitudinal energy distributions of the emitted electrons. Recently TESS has been upgraded to increase the instrument sensitivity for operation with low QE materials under UV illumination. Our R&D facilities also include in-vacuum quantum efficiency measurement, XPS, STM, plus ex-vacuum optical and STM microscopy for surface metrology. Intrinsic photocathode emittance is affected by many factors including illumination wavelength and surface roughness. We present energy distribution measurements for electrons emitted from copper, niobium and zirconium photocathode samples with measured levels of surface roughness under illumination by wavelengths between 256 and 291 nm. We also present an update on progress to establish a multi-alkali photocathode preparation facility to support the CLARA** linear accelerator.
* Proc. FEL’13, TUPPS033, 290-293 ** CLARA Conceptual Design Report J. Inst. 9 T05001 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC17 | |
| About • | paper received ※ 04 October 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| WEPNEC19 | Optimisation of the PERLE Injector | 107 |
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| The injector for PERLE, a proposed electron Energy Recovery Linac (ERL) test facility for the LHeC and FCC-eh projects, is intended to deliver 500 pC bunches at a repetition rate of 40.1 MHz for a total beam current of 20 mA. These bunches must have a bunch length of 3 mm rms and an energy of 7 MeV at the entrance to the first linac pass while simultaneously achieving a transverse emittance of less than 6 mm mrad. The injector is based around a DC photocathode electron gun, followed by a focusing and normal conducting bunching section, a booster with 5 independently controllable SRF cavities and a merger into the main ERL. A design for this injector from the photocathode to the exit of the booster is presented. This design was simulated using ASTRA for the beam dynamics simulations and optimized using the many objective optimization algorithm NSGAIII. The use of NSGAIII allows more than three beam parameters to be optimised simultaneously and the trade-offs between them to be explored. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC19 | |
| About • | paper received ※ 01 October 2019 paper accepted ※ 11 November 2019 issue date ※ 24 June 2020 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |