WG2022
KEK, Ibaraki, Japan
JAEA, Ibaraki-ken, Japan
Kyungpook National University, Daegu, Republic of Korea
Kyungpook National University, Daegu, Republic of Korea
KEK, Ibaraki, Japan
| Paper | Title | Page |
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WG2022 |
Envelope Matching from Injector to Main Linac for ERL | |
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| Since the brilliance of electron beams in Energy Recovery Linac (ERL) is primarily determined by the performance of its injector, the improvement of the injector performance is essential issue. After the injector, the electron beams are accelerated by a main linac to relativistic energy region, in which an emittance growth due to space charge force can be ignored. Because an injected beam with lower energy and a returned beam with higher energy pass through the same main linac, the beam optics in the main linac is restricted to design a reasonable optics throughout the return loop. Therefore, minimization of the emittance, and matching of beam optics to that of the return loop have to be carried out during the injector optimization. The injector parameters have been optimized using multi-objective method with genetic algorithm and a particle tracking code GPT. However, the optimized emittance was far larger than a target emittance, so that some conflict between the minimization of emittance and the restriction of beam optics have been found in the optimization. We report the optimization results, and the strategy to avoid the conflict and to produce a reasonable beam performance. | ||
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Slides WG2022 [2.786 MB] | |
| WG2025 | Investigation of the Effect of Space Charge in the compact-Energy Recovery Linac | 78 |
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| Compact energy recover linear(ERL) accelerator is a prototype of the 5 GeV ERL accelerator at KEK. The injector system has two SRF cavities which have the frequency of 1.3 GHz. It accelerates the bunches to the energy of 5 MeV. This beam was injected to the main ring and then it was accelerated to energy of 35 MeV at the main superconducting RF linac. Due to the low beam energy on the main ring, the investigation of the effect of space charge (SC) which causes the growth of the energy spread is important to produce the low emittance beam. For the production of the low emittance beam, the optimization of the merger was performed. To obtain smaller emittance at the exit of merger, the effect of the energy spread was also investigated by changing of the kd which is defined by the ratio of energy spread to length of the bunch. In this calculation, we got the noralized transverse emittance of 0.74 mm-mrad at the exit of merger section. The effect of the SC was estimated on the main SRF section, arc section and deceleration section. From the results of the study of SC effect in the c-ERL, it is shown that the optics distortion due to the SC needs to be corrected. | ||
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Slides WG2025 [0.980 MB] | |