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Journal Articles

Development of semiconductor clover switch for short-circuit protection of Klystron for J-PARC accelerator

Ono, Ayato; Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.831 - 834, 2021/10

The Ignitron is used in the clover device of the klystron power supply for RF acceleration in the J-PARC LINAC. However, this ignitron uses mercury, the use of which is restricted worldwide, and its production is expected to be discontinued in the future. Therefore, we designed a semiconductor clover switch for short-circuit protection of klystron using a MOS gate thyristor. We have manufactured an oval-type board module that realizes an operating output of 3 kV, 40 kA, and 50 $$mu$$s per board. For the control power supply to each board module assuming a high voltage of 120 kV, we adopted a self-power supply method that creates a control power supply with a high-voltage DCDC converter from the voltage shared and charged by each board module. It was possible to confirm the operating performance on a 1/4 scale (30 kV, 40 kA) against the voltage of the existing equipment (120 kV, 40 kA) by connecting ten oval board modules in series. The output test result will be reported.

Journal Articles

A Possible modification of ceramic chambers in the injection area at the RCS in J-PARC

Shobuda, Yoshihiro; Kamiya, Junichiro; Takayanagi, Tomohiro; Horino, Koki*; Ueno, Tomoaki*; Yanagibashi, Toru*; Kotoku, Hirofumi*

Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.3205 - 3208, 2021/08

At the injection area of the RCS in J-PARC, the interaction between the copper stripes (RF-shields) on the ceramic chambers and the external magnetic fields modulatesthe magnetic fields in the chamber, causing beam losses for a special tune. A ceramic chamber spirally covered by the stripes is a candidate to mitigate the modulations. In this report, we numerically and experimentally investigate how the interaction is suppressed, while sustaining the beam impedance enhancement within tolerable at the RCS.

JAEA Reports

Proposal of safe and secure maintenance method to realize long-term stable operation of electromagnet power supply

Ono, Ayato; Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu

JAEA-Technology 2021-005, 40 Pages, 2021/05

JAEA-Technology-2021-005.pdf:4.27MB

The 3-GeV rapid cycling synchrotron of Japan Proton Accelerator Research Complex (J-PARC) uses a large number of electromagnet power supplies in order to manipulate a high-intensity beam of 1 MW. These devices have been specially developed to meet the requirement to achieve acceleration of the 1-MW proton beams. State-of-the-art technologies are used to these devices. To achieve stable operation with few failures, and to prevent major troubles in the event of a failure, it is necessary to maintain the performance of the devices under the appropriate and accurate management strategy with an enough understanding of its characteristics. However, since the specification and function of each device is different respectively, and it is also produced by different manufacturer, we have to maintain adequately according to the structure, configuration and features of the apparatus. There are typically three major stages in the maintenance works. First, "Daily inspection" is constantly performed to monitor the status of the equipment during operation and check for any errors or abnormalities. Second, "Routine maintenance" is carried out weekly, monthly, or yearly to fix the errors, or to replace the parts that are deteriorated. Third, "Troubleshooting" is conducted to recover from sudden failures. In this report, we will introduce the specific contents of "Routine maintenance", "Daily inspection", and "trouble case" based on the experiences of the electromagnet power supply group. In particular, we will report the work management methods, including ideas for facilitating recovery work. We will also summarize the important points of a matter that does not depend on the configuration, structure, and characteristics of the equipment.

Journal Articles

Kicker power supply for J-PARC 3-GeV RCS with SiC-MOSFET

Takayanagi, Tomohiro; Ono, Ayato; Ueno, Tomoaki*; Horino, Koki*; Togashi, Tomohito; Yamamoto, Kazami; Kinsho, Michikazu; Koizumi, Isao*; Kawamata, Shunsuke*

JPS Conference Proceedings (Internet), 33, p.011020_1 - 011020_6, 2021/03

We are developing a new kicker power supply for J-PARC 3-GeV RCS (Rapid-Cycling Synchrotron) using the next generation power semiconductor SiC-MOSFET with high withstand voltage, low loss, and superior high frequency characteristics. The three major circuits adopted for the RCS kicker power supply, the thyratron switch, the PFN circuit of coaxial cable type, and the end clipper for reflection wave absorption, has been realized with a single modular circuit board based on the LTD circuit. The new kicker power supply realizes stable operation, miniaturization and energy saving by using power semiconductors. The required high voltage can be output by stacking the 800V/2kA modular circuit board in series. The details of circuit design and the results of achieving an output of half 20kV/2kA against the target specification of 40kV/2kA are presented here.

JAEA Reports

Construction of a design model for an electromagnet power supply with safety and reliability in the accelerator

Ono, Ayato; Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu

JAEA-Technology 2020-023, 40 Pages, 2021/02

JAEA-Technology-2020-023.pdf:2.98MB

The 3 GeV rapid cycling synchrotron of Japan Proton Accelerator Research Complex (J-PARC) uses a large number of electromagnet power supplies in order to generate a high-intensity beam of 1 MW. These devices have been specially developed to meet the required specifications of the proton beams. Ten years have passed since the 3 GeV synchrotron had started operation, and we need to replace and update of the components due to failures caused by the aging deterioration. Since the J-PARC is used by many users, it is quite important to recover as soon as possible when a trouble occurs. However, we often spend lots of time to investigate the status and cause of the problem, then it results in the delay of recovery work. One of the major reasons is due to the differences in the manufacturers of sensors and monitors. Therefore, we have to create a manual for each power supply and prepare some exclusive tools. However, troubles rarely occur in the same state and situation, so we have to rely on the experience and knowledge. Even for power supplies with different purposes and specifications, some components, such as sensors, can be shared in many cases. In addition, if the concept of the interlock system, for monitoring the status of the power supply and detecting malfunctions, is shared between the different power supplies, the method and response for failure investigation can be standardized. By using a device with good maintainability, the accelerator operation will be more stable and reliable. In this report, we introduce the necessity of sharing the design concept and common parts. We also explain the basic design model for safety and reliability, using an example of manufacturing an electromagnet power supply for the 3 GeV synchrotron.

Journal Articles

Semiconductor switch power supply for RCS kicker

Takayanagi, Tomohiro; Ono, Ayato; Horino, Koki*; Ueno, Tomoaki*; Togashi, Tomohito; Yamamoto, Kazami; Kinsho, Michikazu

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.25 - 28, 2020/09

We have been developing a semiconductor switch power supply to replace the RCS kicker power supply in J-PARC. A SiC MOSFET is used as a power semiconductor element, and a radially symmetric LTD circuit is used for the circuit board. The power supply consists of a combination of two types of circuit boards: a main circuit board, which includes the circuits of the thyratron, PFN and end clipper provided in RCS kicker power supplies, on a single module board, and a correction board, which compensates for flat-top droop. A single main circuit board can provide 800V/2kA output, and 52 main circuit boards and 20 correction boards have been used to successfully achieve the high voltage of 40kV and flat-top flatness of less than $$pm$$0.2%. Furthermore, a preliminary test of the dual-parallel circuit was conducted for a twin kicker power supply configuration, which is required for the RCS kicker power supply. The evaluation results and prospects are presented.

Journal Articles

Development of ignitron alternative semiconductor switch for J-PARC accelerator

Ono, Ayato; Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.590 - 593, 2020/09

At J-PARC, an ignitron is used for the clover device of the klystron power supply for high-frequency acceleration of a linear accelerator. Ignitron uses mercury, which is of limited use worldwide, and is expected to be discontinued in the future. Therefore, a semiconductor switch for ignitron substitution using a MOS gate thyristor is designed. In order to be used as a crowbar device, a switch capable of resisting an operating output of 120 kV, 40 kA, 50 us is required. We have realized an oval type substrate module that achieves an operating output of 3 kV, 40 kA, 50 us per substrate. It was possible to confirm the operating performance on a 1/10 scale (12 kV, 40 kA) against the voltage of the existing equipment (120 kV, 40 kA) by connecting four oval board modules in series. The output test result will be reported.

Journal Articles

Comparative studies of three-dimensional analysis and measurement for establishing pulse electromagnet design

Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*; Ono, Ayato; Yamamoto, Kazami; Kinsho, Michikazu

IEEE Transactions on Applied Superconductivity, 30(4), p.4901605_1 - 4901605_5, 2020/06

 Times Cited Count:0 Percentile:0(Engineering, Electrical & Electronic)

Journal Articles

Development of low inductance circuit for radially symmetric circuit

Takayanagi, Tomohiro; Ueno, Tomoaki; Horino, Koki

Journal of Physics; Conference Series, 1350(1), p.012183_1 - 012183_7, 2019/12

 Times Cited Count:0 Percentile:0.07

As one of the advanced research and development for maintaining the stable operation of J-PARC RCS, we are developing semiconductor switch circuit for thyratron substitute adopted in kicker system. Radiation symmetric type circuits using semiconductors of SIC-MOSFETs are composed of circuits in which many semiconductor switches are multiplexed in parallel. Since the lengths of all parallel circuits are equal, the output waveform will not be distorted due to timing jitter or impedance. This circuit is useful for outputting the waveform of ultrafast short pulse. Therefore, we have developed a circuit that achieves further low inductance by making the power transmission circuit into a double circular ring structure equal to the coaxial shape. Compare the inductance value obtained from the structure and the output waveform. In addition, we compare the calculation and the measurement in the test and present the verification result of the developed circular ring structure.

Journal Articles

Development of pulse power supply for kicker using power semiconductor and alternative switch for ignitron

Takayanagi, Tomohiro; Ono, Ayato; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.75 - 79, 2019/07

We will replace the Thyratron and Ignitron discharge type switch with a semiconductor switch capable of more stable operation. The thyratron alternative switch used by the kicker power supply manufactured the radial symmetric module substrate of the 800V/2kA output which was built by LTD circuit using SiC-MOSFET. By making the power transfer structure between module substrates stacked for high voltage output into a coaxial ring type, a further reduction in inductance is realized. We report the results of evaluating a pulse output of 20kV/1kA (final specification is 40kV/2kA). Ignitron, which is used as a high-power klystron clover switch, has the potential to be discontinued in the future because it uses mercury, which has limited use worldwide. LINAC's klystron clover switches require a working output of 50kV at 120kV/40kA. We fabricated 3kV/40kA oval type module substrate using MOS gate thyristor. Report on preliminary test results.

Journal Articles

Development of ignitron alternative semiconductor switch and new kicker power supply for J-PARC accelerator

Ono, Ayato; Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.399 - 403, 2019/07

J-PARC uses an ignitron switch as the klystron power source clover device and a thyratron switch as the kicker power system. Ignitron uses mercury, which is of limited use worldwide, and is expected to be discontinued in the future. Therefore, a semiconductor switch for ignitron substitution using a MOS gate thyristor is designed. In order to be used as a crowbar device, a switch capable of resisting an operating output of 120 kV, 40 kA, 50 us is required. We have realized an oval type substrate module that achieves an operating output of 3 kV, 40 kA, 50 us per substrate. In addition, we adopted a LTD circuit using SiC-MOSFET as an alternative switch for thyratron, and produced a radially symmetric pulse power supply circuit to which this circuit was applied. This circuit board achieves a rise of 250 ns or less, and a flat top of 1.5 us or more necessary for the RCS kicker power supply system, with a pulse output of 800 V and 2 kA per circuit board. We report on the power test results at 20 kV.

Journal Articles

Development of radiation resistant monitoring camera system

Takeuchi, Tomoaki; Otsuka, Noriaki; Watanabe, Takashi*; Tanaka, Shigeo*; Ozawa, Osamu*; Komanome, Hirohisa*; Ueno, Shunji*; Tsuchiya, Kunihiko

Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 3 Pages, 2018/11

no abstracts in English

Journal Articles

Development of a new modular switch using a next-generation semiconductor

Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*

Journal of Physics; Conference Series, 1067, p.082019_1 - 082019_6, 2018/10

 Times Cited Count:0 Percentile:0.11

Journal Articles

Development of solid-state switch for power supply with SiC-MOSFET

Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.244 - 248, 2018/08

We will present the development of super high voltage short pulse switch power supply aiming at high performance of 3 GeV synchrotron accelerator pulsed electromagnet power supply. We are developing the switch power supply using SiC-MOSFET of the next generation power semiconductor which is higher in breakdown voltage, lower loss, and higher frequency operation than the current mainstream Si power semiconductors. The SiC conversion of semiconductors enables commercialization of thyratron substitute switches and power-saving small size switching power supplies. However, products that satisfy the specification of the thyratron (80kV/4kA) adopted for the J-PARC 3 GeV-RCS kicker power supply with one module have not been developed. Therefore, it is necessary to construct a circuit in which power semiconductors are multiplexed in series and parallel. In addition, the high-speed short pulse waveform required for the kicker power supply is designed with consideration of the circuit impedance such as inductance and stray capacitance separately from the performance improvement of the power semiconductor. Therefore, a circular radially symmetric circuit was constructed in which power semiconductors were concentrically arranged and the impedance of all parallel circuits could be made equal. As a result, waveform distortion caused by the difference in circuit impedance could be suppressed. This structure is adopted in the LTD circuit and it is indispensable for the development of semiconductor new kicker power supply. In this presentation, the results of the preliminary test and the evaluating test are reported.

Journal Articles

A New pulse magnet for the RCS injection shift bump magnet at J-PARC

Takayanagi, Tomohiro; Yamamoto, Kazami; Kamiya, Junichiro; Saha, P. K.; Ueno, Tomoaki*; Horino, Koki*; Kinsho, Michikazu; Irie, Yoshiro*

IEEE Transactions on Applied Superconductivity, 28(3), p.4100505_1 - 4100505_5, 2018/04

JAEA Reports

Degradation behavior of optical components by gamma irradiation (Contract research)

Takeuchi, Tomoaki; Shibata, Hiroshi; Hanakawa, Hiroki; Uehara, Toshiaki*; Ueno, Shunji*; Tsuchiya, Kunihiko; Kumahara, Hajime*; Shibagaki, Taro*; Komanome, Hirohisa*

JAEA-Technology 2017-026, 26 Pages, 2018/02

JAEA-Technology-2017-026.pdf:4.0MB

Under severe accidents, high-integrity transmission techniques are necessary so as to monitor the situation of the nuclear power plant. In this study, effects of gamma irradiation up to 10$$^{6}$$Gy on properties of optical devices were evaluated toward the development of a radiation-resistant in-water wireless transmission system using visible light. After the irradiation, for the LEDs, the total luminous flux decreased and the browning of resin lenses occurred. Meanwhile, the current-voltage characteristics hardly changed. For the PDs, the light sensitivity decreased and the browning of resin window occurred. The dark currents of PDs did not become large enough to adversely affect transmission. These results indicated that both the decreases of the total luminous flux of the LEDs and the light sensitivity of the PDs were mainly caused by not the degradation of the semiconductor parts but the browning of the resin parts by the irradiation. In addition, basic decrease behaviors of light transmission of several different types of glasses by gamma irradiation were also obtained so as to select the suitable optical windows and filters for the developing radiation-resistant in-water wireless transmission system.

Journal Articles

Development of a new power supply for the RCS kicker magnet with the LTD circuit of SiC-MOSFETs

Takayanagi, Tomohiro; Kinsho, Michikazu; Yamamoto, Kazami; Ueno, Tomoaki*; Horino, Koki*; Tokuchi, Akira*; Mushibe, Yoichi*

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.45 - 49, 2017/12

J-PARC RCS needs updating of equipment after 10 years since the start of operation. Therefore, a pulse power supply applying a next generation semiconductor (SiC-MOSFET) with low switching loss and high breakdown voltage are investigated This supply constructs a serial / parallel multiplexing circuit using a SiC-MOSFET and a plurality of large capacity capacitors with one circuit board (LTD). By using this board as a main board and adopting a multistage hierarchical structure, it is possible to satisfy the specifications of the RCS kicker power supply with a voltage of 40 kV, a current of 4 kA and a rectangular wave pulse width of 1500 ns. Moreover, by adding a plurality of correction boards of 40 V and arbitrarily setting the operation trigger of the board, flatness correction is also possible. It was confirmed that the results of the preliminary test with the maximum output of 4 kV / 2 kA by are effective for maintaining stable operation at the RCS high intensity beam output.

Journal Articles

A Failure investigation of the beam collimator system in the J-PARC 3 GeV rapid cycling synchrotron

Okabe, Kota; Yamamoto, Kazami; Kamiya, Junichiro; Takayanagi, Tomohiro; Yamamoto, Masanobu; Yoshimoto, Masahiro; Takeda, Osamu*; Horino, Koki*; Ueno, Tomoaki*; Yanagibashi, Toru*; et al.

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.853 - 857, 2017/12

The most important issue is to reduce the uncontrolled beam loss in the high intensity hadron accelerator such as J-PARC proton accelerators. The J-PARC 3 GeV Synchrotron (RCS) has a collimator system which narrows a high intensity beam in the RCS. After startup of RCS in 2007, the collimator system of the RCS worked well. However, in April 2016, vacuum leakage at the collimator system occurred during the maintenance operation. To investigate a cause of the failure, we took apart iron shields of the collimator reducing exposed dose of operators. As a result of inspection, we succeeded to identify the cause of the vacuum leakage failure. In this presentation, we report the failure investigation of the beam collimator system in the RCS.

Journal Articles

Present status and future plan of the J-PARC RCS injection bump system

Takayanagi, Tomohiro; Ueno, Tomoaki; Horino, Koki; Togashi, Tomohito; Tobita, Norimitsu*; Yamamoto, Kazami; Kinsho, Michikazu

Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.699 - 702, 2016/11

no abstracts in English

Journal Articles

Development of radiation-resistant in-water wireless transmission system

Takeuchi, Tomoaki; Otsuka, Noriaki; Shibagaki, Taro*; Komanome, Hirohisa*; Ueno, Shunji*; Tsuchiya, Kunihiko

Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.379 - 386, 2016/07

no abstracts in English

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