Rod-filter-field optimization of the J-PARC RF-driven H− ion source

Ueno, Akira; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Yamazaki, S.; Oguri, H.

doi:10.1063/1.4916437

Cited by 8 publications

(8 citation statements)

References 7 publications

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“…3(b), in which the 30MHz-RF matching network composed of two VVCs (3~30pF, 9kV) [6], a part of the 2MHz-RF matching network (an antenna and the external inductance L x ) and the current transformer MODEL-4997 are shown. There are three available PCHs (#1~#3) for the J-PARC operation [11,14]. The #2 and #3 PCHs were fabricated with the same design.…”

Section: Procedures Of Maintenance and Pre-conditioningmentioning

confidence: 99%

“…The #1 PCH has slightly different shapes of the RFMs and pipes for the RFMs. The details of the rod-filterfield optimization are presented in reference [14]. Each PCH is pre-conditioned including pre-cesiation to produce the J-PARC requirements stably.…”

Section: Procedures Of Maintenance and Pre-conditioningmentioning

confidence: 99%

“…(2) The AMFC around the beam hole of the PE, which increases the I H -by about 1.1 times [8]. (3) The low T PE (around 60C) operation, which decreases the transverse emittances by about 0.75 times [4,11,14]. (4) The gapped RFMs, which compensate the individual difference of the magnets and decrease the required P RFN by about 0.8 times [14].…”

Section: -9mentioning

confidence: 99%

“…(3) The low T PE (around 60C) operation, which decreases the transverse emittances by about 0.75 times [4,11,14]. (4) The gapped RFMs, which compensate the individual difference of the magnets and decrease the required P RFN by about 0.8 times [14]. (5) The almost perfectly matched 2MHz-RF matching network, which makes the operation stable [6].…”

Section: -9mentioning

confidence: 99%

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Maintenance and operation procedure, and feedback controls of the J-PARC RF-driven H− ion source

Ueno

Ohkoshi

Ikegami

et al. 2015

AIP Conference Proceedings

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Abstract. In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) second stage requirements of an H¯ ion beam of 60mA within normalized emittances of 1.5mm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500s25Hz) and a life-time of longer than 1month, the J-PARC cesiated RF-driven H¯ ion source was developed by using an internal-antenna developed at the Spallation Neutron Source (SNS). The maintenance and operation procedure to minimize the plasma chamber (PCH) replacement time on the beam line, which is very important to maximize the J-PARC beam time especially for an antenna failure, is presented in this paper. The PCH preserved by filling argon (Ar) gas inside after pre-conditioning including pre-cesiation to produce the required beam at a test-stand successfully produced the required beam on the beam line with slight addition of cesium (Cs). The methods of the feedback controls of a 2MHz-RF-matching, an H¯ ion beam intensity and the addition of Cs are also presented. The RFmatching feedback by using two vacuum variable capacitors (VVCs) and RF-frequency shift produced the almost perfect matching with negligibly small reflected RF-power. The H¯ ion beam intensity was controlled within errors of 0.1mA by the RF-power feedback. The amount of Cs was also controlled by remotely opening a Cs-valve to keep the RF-power lower than a settled value.

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Section: Procedures Of Maintenance and Pre-conditioningmentioning

confidence: 99%

Section: Procedures Of Maintenance and Pre-conditioningmentioning

confidence: 99%

Section: -9mentioning

confidence: 99%

Section: -9mentioning

confidence: 99%

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Maintenance and operation procedure, and feedback controls of the J-PARC RF-driven H− ion source

Ueno

Ohkoshi

Ikegami

et al. 2015

AIP Conference Proceedings

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“…In the upgrade, the radio-frequency quadrupole linac designed to accelerate 30mA H¯ ion beam (30mA-RFQ) and the cesium (Cs) free H¯ ion source driven with a lanthanum hexaboride (LaB 6 ) filament were replaced with a 50mA-RFQ and a cesiated RF-driven H¯ ion source. The J-PARC new source was developed by using an internal-antenna developed at the spallation neutron source (SNS) [2,3,4,5,6,7,8,9,10], based upon J-PARC prototype sources driven with a LaB 6 or two tungsten (W) filaments [11]. The requirements for the source are an H¯ ion beam of 60mA within normalized emittances of 1.5mm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500s25Hz) and a life-time of longer than 1month.…”

Section: Introductionmentioning

confidence: 99%

Emittance measurements for optimum operation of the J-PARC RF-driven H− ion source

Ueno

Ohkoshi

Ikegami

et al. 2015

AIP Conference Proceedings

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Maintenance and operation procedure, and feedback controls of the J-PARC RF-driven H -ion source Abstract. In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) second stage requirements of an H¯ ion beam of 60mA within normalized emittances of 1.5mm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500s25Hz) and a life-time of longer than 1month, the J-PARC cesiated RF-driven H¯ ion source was developed by using an internal-antenna developed at the Spallation Neutron Source (SNS). The transverse emittances of the source were measured with various conditions to find out the optimum operation conditions minimizing the horizontal and vertical rms normalized emittances. The transverse emittances were most effectively reduced by operating the source with the plasma electrode temperature lower than 70C. The optimum value of the cesium (Cs) density around the beam hole of the plasma electrode seems to be proportional to the plasma electrode temperature. The fine control of the Cs density is indispensable, since the emittances seem to increase proportionally to the excessiveness of the Cs density. Furthermore, the source should be operated with the Cs density beyond a threshold value, since the plasma meniscus shape and the ellipse parameters of the transverse emittances seem to be changed step-function-likely on the threshold Cs value.

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Electrostatic and Electromagnetic Particle-In-Cell Modelling with Monte-Carlo Collision for Negative Ion Source Plasmas

Miyamoto

Shibata

2023

Springer Series on Atomic, Optical, and Plasma Physics

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Rod-filter-field optimization of the J-PARC RF-driven H− ion source

Cited by 8 publications

References 7 publications

Maintenance and operation procedure, and feedback controls of the J-PARC RF-driven H− ion source

Maintenance and operation procedure, and feedback controls of the J-PARC RF-driven H− ion source

Emittance measurements for optimum operation of the J-PARC RF-driven H− ion source

Electrostatic and Electromagnetic Particle-In-Cell Modelling with Monte-Carlo Collision for Negative Ion Source Plasmas

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