We have established and also implemented a nondestructive online monitoring system for measuring the stripper foil degradation, such as foil thinning and pinhole outbreak, for the first time during beam operation in a high-intensity proton accelerator. We aimed to achieve a realistic and longer lifetime of a stripper foil by ensuring proper uses and determining its end of usefulness without any failure. A stripper foil is used for negative hydrogen (${\mathrm{H}}^{-}$) stripping to proton (p) for multiturn charge-exchange injection in high-intensity proton accelerators. A longer foil lifetime is expected, while foil failure during operation should be avoided, as it reduces the accelerator availability and also has serious issues for regular accelerator maintenance. A proper use of the foil should also be ensured to minimize the replacement of the foil magazine, as it involves unhealthy radiation exposure to the workers. We have measured the partially stripped ${\mathrm{H}}^0$ and unstripped ${\mathrm{H}}^{-}$ charge fractions of the injection ${\mathrm{H}}^{-}$ beam out of the stripper foil to understand details of foil degradation, such as foil thinning and pinhole formation due to high-intensity beam irradiation, which are believed to be foil breaking signals. We used two independent beam monitoring devices and precisely measured both ${\mathrm{H}}^0$ and unstripped ${\mathrm{H}}^{-}$ charge fractions by each monitor. As a result, we obtained a detail of foil degradation during operation to determine a realistic end of its usefulness by successfully achieving a record of nearly 2 yr of operation with a single foil without any failures. The detailed measurement result of the foil degradation also gives strong feedback for producing stronger and durable stripper foils. The present research was done by using simple and ordinary beam diagnostic devices including a nondestructive one, which can be easily applied to overcome the stripper foil issues in any similar existing and next-generation further higher-intensity accelerators.

中文翻译：

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首次测量和在线监控剥离箔的变薄和针孔形成，以在高强度促进剂中获得更长的箔寿命

我们已经建立并实施了一种无损在线监测系统，该系统首次在高强度质子加速器的束流操作过程中测量了剥离剂箔的退化，例如箔变薄和针孔破裂。我们的目标是通过确保正确使用并确定其使用寿命结束而没有任何故障，从而使剥离剂箔片具有更长的使用寿命。剥离膜用于负氢（${\mathrm{H}}^{-}$）剥离成质子（p），以便在高强度质子加速器中进行多匝电荷交换注入。预期箔片寿命更长，同时应避免箔片在运行期间发生故障，因为这会降低加速器的可用性，并且对定期的加速器维护也存在严重问题。还应确保正确使用箔纸，以最大程度地减少箔纸盒的更换，因为它涉及对工人的不健康辐射。我们已经测量了部分剥离${\mathrm{H}}^0$ 并没有剥落 ${\mathrm{H}}^{-}$ 进样的电荷分数 ${\mathrm{H}}^{-}$从剥离器箔中射出光束，以了解箔降解的细节，例如由于高强度光束辐照而导致的箔变薄和针孔形成，这被认为是箔破裂信号。我们使用了两个独立的光束监控设备，并精确地测量了两个${\mathrm{H}}^0$ 并没有剥落 ${\mathrm{H}}^{-}$每个监视器的电荷分数。结果，我们获得了运行过程中箔片降解的详细信息，通过成功地使用单个箔片获得了将近2年的运行记录而没有任何故障，从而确定了其实用性。箔片降解的详细测量结果还为生产更坚固耐用的剥离剂箔片提供了强大的反馈。本研究是通过使用简单且普通的光束诊断设备（包括非破坏性设备）完成的，该设备可轻松应用于克服任何类似的现有和下一代更高强度的加速器中的剥离箔问题。