HB2016 - List of Authors (Igarashi, S.)

Paper	Title	Page
MOAM6P60	Recent Progress of J-PARC MR Beam Commissioning and Operation	21
	S. Igarashi KEK, Ibaraki, Japan
	The main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) has been providing 30-GeV proton beams for elementary particle and nuclear physics experiments since 2009. The beam power of 390 kW has been recently achieved with 2·10¹⁴ protons per pulse and the cycle time of 2.48 s for the neutrino oscillation experiment. Main efforts in the beam tuning are to minimize beam losses and to localize the losses at the collimator section. Recent improvements include the 2nd harmonic rf operation to reduce the space charge effect with a larger bunching factor and corrections of resonances near the operation setting of the betatron tune. Because the beam bunches were longer with the 2nd harmonic rf operation, the injection kicker system was improved to accommodate the long bunches. We plan to achieve the target beam power of 750 kW in 2018 by making the cycle time faster to 1.3 s with new power supplies of main magnets, rf upgrade and improvement of injection and extraction devices. The possibility of the beam power beyond 750 kW is being explored with new settings of the betatron tune.
	Slides MOAM6P60 [9.968 MB]
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THAM4Y01	New Arrangement of Collimators of J-PARC Main Ring	543
	M.J. Shirakata, S. Igarashi, K. Ishii, Y. Sato, J. Takano KEK, Ibaraki, Japan
	The beam collimation system of J-PARC main ring has been prepared in order to localize the beam loss into the specified area, especially during the injection period. At the first time, it was constructed as a scraper-catcher system in horizontal and vertical planes which consisted of one halo-scraper and two scattered protons catchers, whose the maximum beam loss capacity was designed to be 450W in the beam injection straight of the ring. In 2012, the scraper was replaced by two collimators with a movable L-type jaw for both planes. Two catchers remained at the same places, and they were used as collimators. This large change of design concept of main ring collimation system was required in order to increase the beam loss capacity more than 3kW. The system worked well but unexpected loss spots still remained in the following arc and straight sections. The four-axis collimator was developed with movable jaw in horizontal, vertical and skew configurations which has high cleaning efficiency. We have four four-axis collimators, two non-skew collimators, and one original catcher. The most effective arrangement of collimators was investigated in this report.
	Slides THAM4Y01 [2.426 MB]
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Recent Progress of J-PARC MR Beam Commissioning and Operation

21

S. Igarashi
KEK, Ibaraki, Japan

The main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) has been providing 30-GeV proton beams for elementary particle and nuclear physics experiments since 2009. The beam power of 390 kW has been recently achieved with 2·10¹⁴ protons per pulse and the cycle time of 2.48 s for the neutrino oscillation experiment. Main efforts in the beam tuning are to minimize beam losses and to localize the losses at the collimator section. Recent improvements include the 2nd harmonic rf operation to reduce the space charge effect with a larger bunching factor and corrections of resonances near the operation setting of the betatron tune. Because the beam bunches were longer with the 2nd harmonic rf operation, the injection kicker system was improved to accommodate the long bunches. We plan to achieve the target beam power of 750 kW in 2018 by making the cycle time faster to 1.3 s with new power supplies of main magnets, rf upgrade and improvement of injection and extraction devices. The possibility of the beam power beyond 750 kW is being explored with new settings of the betatron tune.

Slides MOAM6P60 [9.968 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAM4Y01

New Arrangement of Collimators of J-PARC Main Ring

543

M.J. Shirakata, S. Igarashi, K. Ishii, Y. Sato, J. Takano
KEK, Ibaraki, Japan

The beam collimation system of J-PARC main ring has been prepared in order to localize the beam loss into the specified area, especially during the injection period. At the first time, it was constructed as a scraper-catcher system in horizontal and vertical planes which consisted of one halo-scraper and two scattered protons catchers, whose the maximum beam loss capacity was designed to be 450W in the beam injection straight of the ring. In 2012, the scraper was replaced by two collimators with a movable L-type jaw for both planes. Two catchers remained at the same places, and they were used as collimators. This large change of design concept of main ring collimation system was required in order to increase the beam loss capacity more than 3kW. The system worked well but unexpected loss spots still remained in the following arc and straight sections. The four-axis collimator was developed with movable jaw in horizontal, vertical and skew configurations which has high cleaning efficiency. We have four four-axis collimators, two non-skew collimators, and one original catcher. The most effective arrangement of collimators was investigated in this report.

Slides THAM4Y01 [2.426 MB]

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)