The J-PARC 3-GeV rapid cycling synchrotron (RCS) has recently achieved a 1-MW beam operation with considerably low fractional beam loss of a couple of 10−3 as a result of continuous efforts iterating experiments and numerical simulations. This success of the 1-MW beam operation opened a door to further beam power ramp-up beyond 1 MW; we are now promoting 1.2~1.5-MW-equivalent high-intensity beam tests looking ahead to future upgrades at J-PARC. In this article, we first review the current status of beam loss in the 1-MW beam operation, then presenting the recent results of the 1.2-MW beam tests with particular emphasis on our approaches to beam loss issues. The beam intensity limit of the RCS is also discussed with well-established numerical simulations.

中文翻译：

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J-PARC 3-GeV RCS：1-MW 光束运行及以上

由于不断努力迭代实验和数值模拟，J-PARC 3-GeV 快速循环同步加速器 (RCS) 最近实​​现了 1 MW 光束操作，具有相当低的部分光束损失，仅为 10-3。1 兆瓦光束运行的这一成功为进一步将光束功率提升至 1 兆瓦以上打开了大门；我们现在正在推广 1.2~1.5-MW 等效高强度光束测试，展望未来 J-PARC 的升级。在本文中，我们首先回顾了 1 MW 光束操作中光束损耗的当前状态，然后介绍了 1.2 MW 光束测试的最新结果，特别强调了我们解决光束损耗问题的方法。RCS 的光束强度限制也通过完善的数值模拟进行了讨论。