State of the art online monitoring system for the waste beam in the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Saha, Pranab; Hatakeyama, Shuichiro; Yamamoto, Kazami; Yoshimoto, Masahiro; Harada, Hiroyuki; Hotchi, H.; Shobuda, Yoshihiro; Kinsho, Michikazu; Satou, Kenichirou; Irie, Y.

doi:10.1103/physrevstab.14.072801

Cited by 10 publications

(6 citation statements)

References 7 publications

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“…The injection foil is needed to a charge exchange injection system which mitigates the space charge effect [14]. The foil consists mainly carbon and its thickness is typically 200μg/cm 2 [15]. The scattered particles by the foil had large scattering angles and were lost before they hit the collimators.…”

Section: Distribution Of the Losses Around The Ringmentioning

confidence: 99%

Performance of the beam collimation system in the J-PARC RCS

Yamamoto¹,

Kato

Harada³

et al. 2014

Progress in Nuclear Science and Technology

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The most important issue in a high intensity proton accelerator is to keep the accelerator tunnel in a hands-on-maintenance condition. A collimation system was designed and installed in 3GeV Rapid Cycling Synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) to be localized the beam loss point to a restricted area. The experimental results indicated that the RCS collimation system performs well enough such that nearly all the ring components are maintained in good condition. However, as the beam power increased, unexpected losses downstream of the injection foil increased. Therefore, an additional collimator was installed that successfully reduced such unexpected losses.

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Section: Distribution Of the Losses Around The Ringmentioning

confidence: 99%

Performance of the beam collimation system in the J-PARC RCS

Yamamoto¹,

Kato

Harada³

et al. 2014

Progress in Nuclear Science and Technology

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“…The PBV1-2 are located in the L-3BT line and thus painting area in the vertical direction is also changed in a pulse to pulse. More than 99.6% of incoming H À beam from the linac is stripped to H þ by the first foil so as to inject into the ring [7]. (x and x 0 ) of the injected beam center is matched at a bumped closed orbit made by four chicane bump magnets, SB1-4 together with four horizontal painting bump magnets, PBH1-4.…”

Section: Principles and Design Specifications Of The Pstr Magnetsmentioning

confidence: 99%

“…They are named pulse steering (PSTR) magnets and have already been installed in the linac to the 3-GeV RCS beam transport (L-3BT) line in the 2012 summer shutdown period. Figure 3 [7] shows a layout of the RCS injection area, where location of the newly installed PSTR magnets is shown by two blue arrows. A further schematic and expanded view of the injection area together with injected beam trajectory and the circulating orbit bump offset for injection painting is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Beam emittance control by changing injection painting area in a pulse-to-pulse mode in the 3-GeV rapid cycling synchrotron of Japan Proton Accelerator Research Complex

Saha

Harada

Hayashi

et al. 2013

Phys. Rev. ST Accel. Beams

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The 3-GeV rapid cycling synchrotron (RCS) of Japan Proton Accelerator Research Complex (J-PARC) simultaneously delivers high intensity beam to the Material and Life Science Experimental Facility (MLF) as well as to the main ring (MR) at a repetition rate of 25 Hz. The RCS is designed for a beam power of 1 MW. RCS has to meet not only the need of power upgrade but also the specific requirement of each downstream facility. One of the issues, especially for high intensity operation, is to maintain two different transverse sizes of the extracted beam for MLF and MR; namely, a wider beam for MLF in order to reduce damage on the neutron production target but reversely a narrower one for the MR in order to ensure a permissible beam loss in the beam transport line of 3-GeV to MR and also in the MR. We proposed pulseto-pulse direct control of the transverse painting area during the RCS beam injection process in order to get an extracted beam profile as desired. In addition to two existing dc septum magnets used for fixing injected beam trajectory for MLF beam, two additional dipoles named pulse steering magnets are designed for that purpose in order to control injected beam trajectory for a smaller painting area for the MR. The magnets are already installed in the injection beam transport line and successfully commissioned well in advance before they will be put in normal operation in 2014 for the 400 MeV injected beam energy upgraded from that of the present 181 MeV. Their parameters are found to be consistent to those expected in the corresponding numerical simulations. A trial one cycle user operation run for a painting area of 100 mm mrad for the MR switching from the MLF painting area of 150 mm mrad has also been successfully carried out. The extracted beam profile for the MR is measured to be sufficiently narrower as compared to that for the MLF, consistent with numerical simulation successfully demonstrating validity of the present principle.

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“…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 CT is originally used for the personal protection system (PPS) interlock system with two-stage amplifications of the original signal. More details on the CT can be found in our earlier article [14]. For our present purpose, we fed the amplified and buffered signal into an oscilloscope, which is controlled by an operation interface (OPI).…”

Section: Brief Introduction Of the Present Monitorsmentioning

confidence: 99%

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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State of the art online monitoring system for the waste beam in the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Cited by 10 publications

References 7 publications

Performance of the beam collimation system in the J-PARC RCS

Performance of the beam collimation system in the J-PARC RCS

Beam emittance control by changing injection painting area in a pulse-to-pulse mode in the 3-GeV rapid cycling synchrotron of Japan Proton Accelerator Research Complex

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

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