{"title":"PAL-XFEL 软 X 射线起爆线较短聚焦晶格的可行性研究","authors":"Kook-Jin Moon, Inhyuk Nam, Chi Hyun Shim","doi":"10.1007/s40042-024-01087-7","DOIUrl":null,"url":null,"abstract":"<div><p>At Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL), there is an ongoing consideration of employing elliptically polarizing undulators throughout the entire undulator line to enable polarization control in the soft X-ray undulator line. To utilize the elliptically polarizing undulators, the shorter focusing lattice for soft X-ray undulator line at PAL-XFEL is proposed. The FEL performance of the shorter focusing lattice is estimated by using Ming Xie’s fitting formula and is compared with the current focusing lattice. Due to the increased need for intersections in the shorter focusing lattice, there is a challenge where the effective length of the undulator becomes shorter compared to the current focusing lattice within the same length of the undulator line. Therefore, the use of quadrupoles employed in the hard X-ray undulator line at PAL-XFEL has also been taken into consideration to overcome the reduced effective length of the undulator by increasing the betatron phase advance. Based on the time-dependent FEL simulation results, it can be confirmed that the proposed shorter focusing lattice is sufficiently feasible without compromising FEL performance.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"85 3","pages":"248 - 255"},"PeriodicalIF":0.8000,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Feasibility study of the shorter focusing lattice for soft X-ray undulator line at PAL-XFEL\",\"authors\":\"Kook-Jin Moon, Inhyuk Nam, Chi Hyun Shim\",\"doi\":\"10.1007/s40042-024-01087-7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>At Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL), there is an ongoing consideration of employing elliptically polarizing undulators throughout the entire undulator line to enable polarization control in the soft X-ray undulator line. To utilize the elliptically polarizing undulators, the shorter focusing lattice for soft X-ray undulator line at PAL-XFEL is proposed. The FEL performance of the shorter focusing lattice is estimated by using Ming Xie’s fitting formula and is compared with the current focusing lattice. Due to the increased need for intersections in the shorter focusing lattice, there is a challenge where the effective length of the undulator becomes shorter compared to the current focusing lattice within the same length of the undulator line. Therefore, the use of quadrupoles employed in the hard X-ray undulator line at PAL-XFEL has also been taken into consideration to overcome the reduced effective length of the undulator by increasing the betatron phase advance. Based on the time-dependent FEL simulation results, it can be confirmed that the proposed shorter focusing lattice is sufficiently feasible without compromising FEL performance.</p></div>\",\"PeriodicalId\":677,\"journal\":{\"name\":\"Journal of the Korean Physical Society\",\"volume\":\"85 3\",\"pages\":\"248 - 255\"},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2024-05-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the Korean Physical Society\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s40042-024-01087-7\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the Korean Physical Society","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s40042-024-01087-7","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
浦项加速器实验室 X 射线自由电子激光器(PAL-XFEL)正在考虑在整条起振线上采用椭圆偏振起振子,以实现软 X 射线起振线的偏振控制。为了利用椭圆偏振起爆器,提出了用于 PAL-XFEL 软 X 射线起爆线的较短聚焦晶格。使用谢明的拟合公式估算了较短聚焦晶格的 FEL 性能,并与当前的聚焦晶格进行了比较。由于在更短的聚焦网格中需要更多的交叉点,因此存在一个挑战,即在相同长度的起爆线内,起爆器的有效长度比目前的聚焦网格更短。因此,PAL-XFEL 的硬 X 射线定子线也考虑使用四极子,通过增加贝塔电子管相位提前量来克服定子有效长度缩短的问题。根据随时间变化的 FEL 仿真结果,可以确认所建议的较短聚焦晶格是完全可行的,而且不会影响 FEL 性能。
Feasibility study of the shorter focusing lattice for soft X-ray undulator line at PAL-XFEL
At Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL), there is an ongoing consideration of employing elliptically polarizing undulators throughout the entire undulator line to enable polarization control in the soft X-ray undulator line. To utilize the elliptically polarizing undulators, the shorter focusing lattice for soft X-ray undulator line at PAL-XFEL is proposed. The FEL performance of the shorter focusing lattice is estimated by using Ming Xie’s fitting formula and is compared with the current focusing lattice. Due to the increased need for intersections in the shorter focusing lattice, there is a challenge where the effective length of the undulator becomes shorter compared to the current focusing lattice within the same length of the undulator line. Therefore, the use of quadrupoles employed in the hard X-ray undulator line at PAL-XFEL has also been taken into consideration to overcome the reduced effective length of the undulator by increasing the betatron phase advance. Based on the time-dependent FEL simulation results, it can be confirmed that the proposed shorter focusing lattice is sufficiently feasible without compromising FEL performance.
期刊介绍:
The Journal of the Korean Physical Society (JKPS) covers all fields of physics spanning from statistical physics and condensed matter physics to particle physics. The manuscript to be published in JKPS is required to hold the originality, significance, and recent completeness. The journal is composed of Full paper, Letters, and Brief sections. In addition, featured articles with outstanding results are selected by the Editorial board and introduced in the online version. For emphasis on aspect of international journal, several world-distinguished researchers join the Editorial board. High quality of papers may be express-published when it is recommended or requested.