Measurement of 181 MeV H − ions stripping cross-sections by carbon stripper foil

Saha, Pranab; Yoshimoto, Masahiro; Yamazaki, Yoichi; Hotchi, H.; Harada, Hiroyuki; Okabe, Kota; Kinsho, Michikazu; Irie, Y.

doi:10.1016/j.nima.2014.12.068

Cited by 10 publications

(5 citation statements)

References 8 publications

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“…Once the H 0 and H − fractions are known, the p fraction injected into the RCS can be automatically calculated. The stripping efficiency and the foil thickness can be then estimated by using the measured cross sections [15]. Figure 7 shows the measurement procedure used in the present study.…”

Section: Measurement Principlementioning

confidence: 99%

“…Our aim is also to understand a foil breaking mechanism by measuring details of foil degradation, such as foil thinning and pinhole outbreak information due to continuous highintensity beam irradiation until a foil reaches its end of life. We used two independent but ordinary beam monitoring devices, and details of their characteristics were reported earlier [14,15]. The monitors have been in service for measuring and monitoring stripper foil degradation during RCS operation for more than 10 yr, and there has been no record of any foil failure so far.…”

Section: Introductionmentioning

confidence: 99%

“…The remaining 0.3% of the H − are mainly the partially (single electron) stripped by the first foil. They are called neutral hydrogen H 0 , while the unstripped H − are ideally negligibly small (1.995 × 10 −5 %) [15]. The H 0 and unstripped H − are called waste beams.…”

Section: Introductionmentioning

confidence: 99%

“…Background data with no beam trigger are also taken and subtracted from the data taken with the beam to eliminate the noise in the beam profile. The linearity of the MWPM was also extensively studied and was found to be good [15]. However, due to a comparatively lower beam intensity used to avoid any breaking of the MWPM wires because of overheating, the statistical measurement error of the MWPM is larger than that of CT measurements.…”

Section: Brief Introduction Of the Present Monitorsmentioning

confidence: 99%

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First measurement and online monitoring of the stripper foil thinning and pinhole formation to achieve a longer foil lifetime in high-intensity accelerators

Saha

Yoshimoto

Hatakeyama

et al. 2020

Phys. Rev. Accel. Beams

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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 (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 H 0 and unstripped H − charge fractions of the injection 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 H 0 and unstripped 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.

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Section: Measurement Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Brief Introduction Of the Present Monitorsmentioning

confidence: 99%

See 2 more Smart Citations

First measurement and online monitoring of the stripper foil thinning and pinhole formation to achieve a longer foil lifetime in high-intensity accelerators

Saha

Yoshimoto

Hatakeyama

et al. 2020

Phys. Rev. Accel. Beams

Self Cite

View full text Add to dashboard Cite

show abstract

“…Stripping extraction takes away one or more electrons from the accelerated particles by passing them through a thin stripper foil located at the desired extraction position, thus also breaking any molecular bonds. As the stripped particles have different charge-to-mass ratio than the accelerated whole particles, the stripped ions are deflected away from the original orbit, possibly leading to nearly 100% of extraction efficiency [1,2]. This feature is appealing especially in the production of a high intensity proton beam.…”

Section: Introductionmentioning

confidence: 99%

Lorentz dissociation of hydrogen ions in a cyclotron

Koay

2023

J. Inst.

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Stripping extraction of hydrogen molecular ions has gained interest in the cyclotron industry due to its high extraction efficiency. However, the magnetic field could result in undesired Lorentz dissociation of the hydrogen anion/molecular ions during acceleration. Studies of dissociation under electric fields comparable to that of a Lorentz-transformed magnetic field in a typical cyclotron (a few MV/cm) are sparse. Hence, in order to fill in the missing yet crucial information when designing a cyclotron, this work compiles and summarizes the study of Lorentz dissociation of H-, H+ 2 and H+ 3 for stripping extraction in a cyclotron.

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Measurement of continuous degradation of a stripper foil during ths operation with 300 kW beam power in the 3-GeV RCS of J-PARC

Saha

Yoshimoto

Hotchi

et al. 2015

J Radioanal Nucl Chem

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Measurement of 181 MeV H − ions stripping cross-sections by carbon stripper foil

Cited by 10 publications

References 8 publications

First measurement and online monitoring of the stripper foil thinning and pinhole formation to achieve a longer foil lifetime in high-intensity accelerators

First measurement and online monitoring of the stripper foil thinning and pinhole formation to achieve a longer foil lifetime in high-intensity accelerators

Lorentz dissociation of hydrogen ions in a cyclotron

Measurement of continuous degradation of a stripper foil during ths operation with 300 kW beam power in the 3-GeV RCS of J-PARC

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