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WG5001 |
Proposal of a Diamond-based Beam Halo Monitor for an Energy Recovery Linac |
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- H. Aoyagi, T. Bizen, T. Itoga, N. Nariyama
JASRI/SPring-8, Hyogo, Japan
- Y. Asano, H. Kitamura, T. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
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Funding: This work is partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (c) 21604017.
We propose a diamond-based beam halo monitor for an Energy Recovery Linac (ERL). Diamond detectors are operated in photoconductive mode, and installed in a beam duct to measure the intensity of the beam halo directly. Pulse-by-pulse measurement is adopted to suppress the background noise efficiently. The lower detection limit of 2·103 electrons/pulse for single-shot measurement has been achieved. This monitor had been originally developed for SPring-8 Angstrom Compact free electron LAser (SACLA) to prevent radiation damage of undulator magnets, and good performances have been provided until now. The diamond-based beam halo monitor should be useful to control the beam and avoid the unnecessary radiation damage of the components of ERL. Based on the feasibility tests and the operational results of this monitor at SACLA, we will discuss the possibility of the monitor to adapt to the ERL system.
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Slides WG5001 [2.808 MB]
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WG5006 |
Availability of Optical Fiber Based Beam Loss Monitor at SACLA XFEL Facility |
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- T. Itoga, X.-M. Maréchal
JASRI/SPring-8, Hyogo-ken, Japan
- Y. Asano
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
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An optical fiber-based Cerenkov beam loss monitor (CBLM) has been developed as a real-time and long-range detection tool for the SPring-8 angstrom compact free electron laser (SACLA) in order to control electron beam losses. Based on the tests carried out at the 250 MeV SPring-8 Compact SASE Source (SCSS) prototype accelerator, large core (400 μm), long (>150 m) multimode fibers were selected and installed at the SACLA. We report the approach chosen to insure that the required sensitivity (≤ 1 pC) could be obtained over more than one hundred meters. A beam-based approach was used to characterize (attenuation, signal amplitude) different fibers (diameter, index profile, numerical aperture) and to select the most appropriate one. The results of the first few months of operation show that the SPring-8 CBLM has performed efficiently, with a detection limit below 1 pC per pulse across the 110 meters of the in-vacuum type undulators, and with a position accuracy of less than 1 m, and could be useful to apply to various electron accelerators especially in the tuning stage.
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Slides WG5006 [1.183 MB]
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