State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex
At the 3-GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex, we have minimized the beam loss at high-intensity beam operation up to the designed beam power of 1 MW. This was accomplished through systematic numerical simulations and experimental studies conducted ove...
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| Format: | Article |
| Language: | English |
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American Physical Society
2025-07-01
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| Series: | Physical Review Accelerators and Beams |
| Online Access: | http://doi.org/10.1103/tbyh-jcq3 |
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| author | P. K. Saha H. Harada F. Tamura K. Okabe M. Yoshimoto Y. Shobuda H. Okita K. Kojima T. Nakanoya S. Hatakeyama T. Takayanagi K. Yamamoto H. Hotchi |
| author_facet | P. K. Saha H. Harada F. Tamura K. Okabe M. Yoshimoto Y. Shobuda H. Okita K. Kojima T. Nakanoya S. Hatakeyama T. Takayanagi K. Yamamoto H. Hotchi |
| author_sort | P. K. Saha |
| collection | DOAJ |
| description | At the 3-GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex, we have minimized the beam loss at high-intensity beam operation up to the designed beam power of 1 MW. This was accomplished through systematic numerical simulations and experimental studies conducted over 2 years from 2020 and 2022. We first focused on mitigating uncontrolled beam losses originating from the foil scattering of the circulating beam, which results in high residual radiation levels, particularly in the injection area. These uncontrolled beam losses were well mitigated by reducing the stripper foil size and optimizing the injection beam size. Subsequently, we attempted to minimize the space charge effects and the associated beam losses at 1 MW by implementing several measures, such as refining both longitudinal and transverse injection paintings, correcting betatron resonances, and optimizing betatron tunes at injection. Consequently, we reduced beam losses throughout the RCS, including the collimator area, by 80% as compared to those observed at 1-MW trial operation in 2020. The residual beam loss at 1 MW is now estimated to be well below 10^{−3}, which is primarily attributed to residual foil scattering-induced beam losses. Notably, beam losses in areas other than the collimator section are uncontrolled and required to be well minimized to ensure stable operation and regular accelerator maintenance. We have considerably reduced the machine activation, achieving a 1-order-of-magnitude decrease at the collimator compared to that in 2020. This improvement has enabled the RCS to maintain more than 98% availability for user operation recently. The simulation and measurement results, demonstrating good agreement, provide a detailed understanding of the beam loss mechanism at each step and guide the implementation of effective optimizations. |
| format | Article |
| id | doaj-art-d333ccd8a6d644d8bbcbbc47c37ee03d |
| institution | DOAJ |
| issn | 2469-9888 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Accelerators and Beams |
| spelling | doaj-art-d333ccd8a6d644d8bbcbbc47c37ee03d2025-08-20T02:47:21ZengAmerican Physical SocietyPhysical Review Accelerators and Beams2469-98882025-07-0128707420110.1103/tbyh-jcq3State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research ComplexP. K. SahaH. HaradaF. TamuraK. OkabeM. YoshimotoY. ShobudaH. OkitaK. KojimaT. NakanoyaS. HatakeyamaT. TakayanagiK. YamamotoH. HotchiAt the 3-GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex, we have minimized the beam loss at high-intensity beam operation up to the designed beam power of 1 MW. This was accomplished through systematic numerical simulations and experimental studies conducted over 2 years from 2020 and 2022. We first focused on mitigating uncontrolled beam losses originating from the foil scattering of the circulating beam, which results in high residual radiation levels, particularly in the injection area. These uncontrolled beam losses were well mitigated by reducing the stripper foil size and optimizing the injection beam size. Subsequently, we attempted to minimize the space charge effects and the associated beam losses at 1 MW by implementing several measures, such as refining both longitudinal and transverse injection paintings, correcting betatron resonances, and optimizing betatron tunes at injection. Consequently, we reduced beam losses throughout the RCS, including the collimator area, by 80% as compared to those observed at 1-MW trial operation in 2020. The residual beam loss at 1 MW is now estimated to be well below 10^{−3}, which is primarily attributed to residual foil scattering-induced beam losses. Notably, beam losses in areas other than the collimator section are uncontrolled and required to be well minimized to ensure stable operation and regular accelerator maintenance. We have considerably reduced the machine activation, achieving a 1-order-of-magnitude decrease at the collimator compared to that in 2020. This improvement has enabled the RCS to maintain more than 98% availability for user operation recently. The simulation and measurement results, demonstrating good agreement, provide a detailed understanding of the beam loss mechanism at each step and guide the implementation of effective optimizations.http://doi.org/10.1103/tbyh-jcq3 |
| spellingShingle | P. K. Saha H. Harada F. Tamura K. Okabe M. Yoshimoto Y. Shobuda H. Okita K. Kojima T. Nakanoya S. Hatakeyama T. Takayanagi K. Yamamoto H. Hotchi State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex Physical Review Accelerators and Beams |
| title | State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex |
| title_full | State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex |
| title_fullStr | State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex |
| title_full_unstemmed | State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex |
| title_short | State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex |
| title_sort | state of the art beam loss minimization at high intensity beam operation of the 3 gev rapid cycling synchrotron at the japan proton accelerator research complex |
| url | http://doi.org/10.1103/tbyh-jcq3 |
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