ECRIS2012 - List of Authors (Higurashi, Y.)

Paper

Title

Page

Design of Web-based Interface to RIKEN 28 GHz Super-conducting ECR Ion Source and the Future Plan

61

A. Uchiyama
Sokendai, Ibaraki, Japan
K. Furukawa
KEK, Ibaraki, Japan
Y. Higurashi, M. Komiyama, T. Nakagawa, K. Ozeki
RIKEN Nishina Center, Wako, Japan

A new RIKEN 28 GHz superconducting ECR ion source (28 GHz-ECRIS) was constructed in 2009 in order to increase the intensity of Uranium ion beam for RIKEN RI beam factory project(RIBF). For effective and stable operation of the 28 GHz-ECRIS, its client system should have an user-friendly man-machine interface. The ECRIS control system was constructed with the Experimental Physics and Industrial Control System (EPICS) as well as RIBF control system. As a result, it was successful to provide the useful clients, such as the operation GUI panels, the XY chart application, and the data acquisition system in EPICS-based system. On the other hand, to keep beam quality from 28 GHz-ECRIS for a long beam service term, it should be possible to operate the ECRIS by members of ion source team at any time. In order to relieve concern in the overseas business trip of members of ion source team, we designed a real-time web-based client system using WebSocket*, which is a new protocol presented by Internet Engineering Task Force (IETF). In this paper, we report the system and development status in detail.
* I. Fette and A. Melnikov. The WebSocket Protocol, IETF HyBi Working Group. 2011.

TUPP17

Installation and Operation of a 28 GHz Gyrotron for the RIKEN Superconducting ECR Ion Source

71

J. Ohnishi, Y. Higurashi, T. Nakagawa
RIKEN Nishina Center, Wako, Japan

The RIKEN 28-GHz ECRIS uses a gyrotron microwave source fabricated by Mitsubishi Electric Corporation. The maximum output power is 10 kW. The gyrotron produces TE02-mode microwaves, which are converted into the TE01 mode by a mode converter. In the first test on the gyrotron performed using a dummy load, we observed the 50-300 Hz ripples of ~500 W in the output power of 1-7 kW, and it was difficult to make a stable operation in the low-power. These ripples were reduced to one-tenth by stabilizing the cathode voltage and then the gyrotron could produce microwaves from < 0.5 kW stably. The operation of the ion source with the 28 GHz gyrotron was started in 2011 and the ion source supplied U and Xe beams to the RIBF for two months. The power of the microwaves fluctuated slowly in the range of 870-1250 W, which influenced the beam current from the ion source. This fluctuation was caused by a slight change of the current of the solenoid of the gyrotron depending on the room temperature. We replaced the power supply with new one which has a current stability of 10ppm per day, and stabilized the microwave power in the range of 5% in the operation of 2 kW successfully.

WEZO02

Design of new 18 GHz ECR for RIKEN RIBF

114

K. Ozeki, Y. Higurashi, T. Nakagawa, J. Ohnishi
RIKEN Nishina Center, Wako, Japan

In RIKEN RIBF, we plan to install a new 18 GHz ECR ion source, which supply the intense beam of highly charged heavy ion beam into the linear accelerator RILAC. By equipping two ion sources, it is expected to be able to develop new beams while we produce the beam for the experiment of RIBF. Based on the structure of 18 GHz ECR ion source which have been developed in RIKEN, this ion source has additional features as follows:

Owing to three solenoid coils, Bext can be adjusted while Bmin is fixed to an optimum value.
We adopt the variable frequency (17.2-18.4 GHz) RF power source. Therefore, further enhancement of the beam intensity is expected because the frequency band suited to a size of plasma chamber is selectable,
In order to simplify the maintenance work, we improved a structure of the chamber.

In this contribution, we report the design of new ion source in detail.

Slides WEZO02 [10.113 MB]

WEPP08

Emittance Measurements for U Ion Beams Produced from RIKEN 28 GHz SC-ECRIS

130

K. Ozeki, Y. Higurashi, T. Nakagawa, J. Ohnishi
RIKEN Nishina Center, Wako, Japan

In order to investigate the ion optical parameters of the beam line of RIKEN 28 GHz SC-ECR ion source into the new heavy ion linac (RILAC II), we measured the emittance of the heavy ion beams form RIKEN 28 GHz SC-ECR ion source. In the test experiments, we observed that the emittance of the U³⁵⁺ beam was ~100 π·mm·mrad (4 rms emittance), which is smaller than the acceptance of the accelerator (~160 π·mm·mrad). The emittance with 28 GHz was almost same as that with 18 GHz and independent on the injected RF power (1~2 kW). The size of emittance increased with decreasing the charge state. We also measured the emittance of U and oxygen ions under the same condition. In this experiment we observed that the emittance of oxygen ions was always larger than the U ion beam for same M/q. In this contribution, we report the experimental results for emittance measurement of highly charged U, Xe and O ions from RIKEN 28 GHz SC-ECR ion source in detail.

THXO03

Recent RIKEN 28 GHz SC-ECRIS Results

159

Y. Higurashi, M. Fujimaki, H. Haba, O. Kamigaito, M. Kidera, M. Komiyama, J. Ohnishi, K. Ozeki
RIKEN Nishina Center, Wako, Japan
T. Aihara, M. Tamura, A. Uchiyama
SHI Accelerator Service Ltd., Tokyo, Japan

For increasing the beam intensity of highly charged heavy ions at RIKEN RIBF, we constructed new SC-ECR ion source. In the spring of 2011, we injected 28GHz microwave into the ion source and obtained first beam. Since then, we made several test experiments for increasing the beam intensity of highly charged Xe and U ion beam, and produced ~60 eμA of U³⁵⁺, ~90 eμA of U³³⁺ at the injected RF power of ~2 kW using sputtering method. In case of Xe²⁵⁺, 250 euA was obtained at RF power of 1.7 kW. Using sputtering method, we produced U³⁵⁺ ion beam longer than one month for the RIBF experiment without break. In the beginning of 2012, we installed additional GM-JT refrigerator to increase the cooling power at 4.2 K, then the total cooling power became higher than 9 W. Using it, we can use higher than 8 W of cooling power for heat load due to the absorbed X-rays. In this summer, we will install the new plasma chamber made of Al for increasing the cooling power. We will also use high temperature oven to increase the U vapor. In this contribution, we report the recent modification of the ion source and test experiments for production of U and Xe ion beam.

Slides THXO03 [49.487 MB]

Paper	Title	Page
TUPP12	Design of Web-based Interface to RIKEN 28 GHz Super-conducting ECR Ion Source and the Future Plan	61
	A. Uchiyama Sokendai, Ibaraki, Japan K. Furukawa KEK, Ibaraki, Japan Y. Higurashi, M. Komiyama, T. Nakagawa, K. Ozeki RIKEN Nishina Center, Wako, Japan
	A new RIKEN 28 GHz superconducting ECR ion source (28 GHz-ECRIS) was constructed in 2009 in order to increase the intensity of Uranium ion beam for RIKEN RI beam factory project(RIBF). For effective and stable operation of the 28 GHz-ECRIS, its client system should have an user-friendly man-machine interface. The ECRIS control system was constructed with the Experimental Physics and Industrial Control System (EPICS) as well as RIBF control system. As a result, it was successful to provide the useful clients, such as the operation GUI panels, the XY chart application, and the data acquisition system in EPICS-based system. On the other hand, to keep beam quality from 28 GHz-ECRIS for a long beam service term, it should be possible to operate the ECRIS by members of ion source team at any time. In order to relieve concern in the overseas business trip of members of ion source team, we designed a real-time web-based client system using WebSocket, which is a new protocol presented by Internet Engineering Task Force (IETF). In this paper, we report the system and development status in detail. I. Fette and A. Melnikov. The WebSocket Protocol, IETF HyBi Working Group. 2011.

TUPP17	Installation and Operation of a 28 GHz Gyrotron for the RIKEN Superconducting ECR Ion Source	71
	J. Ohnishi, Y. Higurashi, T. Nakagawa RIKEN Nishina Center, Wako, Japan
	The RIKEN 28-GHz ECRIS uses a gyrotron microwave source fabricated by Mitsubishi Electric Corporation. The maximum output power is 10 kW. The gyrotron produces TE02-mode microwaves, which are converted into the TE01 mode by a mode converter. In the first test on the gyrotron performed using a dummy load, we observed the 50-300 Hz ripples of ~500 W in the output power of 1-7 kW, and it was difficult to make a stable operation in the low-power. These ripples were reduced to one-tenth by stabilizing the cathode voltage and then the gyrotron could produce microwaves from < 0.5 kW stably. The operation of the ion source with the 28 GHz gyrotron was started in 2011 and the ion source supplied U and Xe beams to the RIBF for two months. The power of the microwaves fluctuated slowly in the range of 870-1250 W, which influenced the beam current from the ion source. This fluctuation was caused by a slight change of the current of the solenoid of the gyrotron depending on the room temperature. We replaced the power supply with new one which has a current stability of 10ppm per day, and stabilized the microwave power in the range of 5% in the operation of 2 kW successfully.

WEZO02	Design of new 18 GHz ECR for RIKEN RIBF	114
	K. Ozeki, Y. Higurashi, T. Nakagawa, J. Ohnishi RIKEN Nishina Center, Wako, Japan
	In RIKEN RIBF, we plan to install a new 18 GHz ECR ion source, which supply the intense beam of highly charged heavy ion beam into the linear accelerator RILAC. By equipping two ion sources, it is expected to be able to develop new beams while we produce the beam for the experiment of RIBF. Based on the structure of 18 GHz ECR ion source which have been developed in RIKEN, this ion source has additional features as follows: Owing to three solenoid coils, Bext can be adjusted while Bmin is fixed to an optimum value. We adopt the variable frequency (17.2-18.4 GHz) RF power source. Therefore, further enhancement of the beam intensity is expected because the frequency band suited to a size of plasma chamber is selectable, In order to simplify the maintenance work, we improved a structure of the chamber. In this contribution, we report the design of new ion source in detail.
	Slides WEZO02 [10.113 MB]

WEPP08	Emittance Measurements for U Ion Beams Produced from RIKEN 28 GHz SC-ECRIS	130
	K. Ozeki, Y. Higurashi, T. Nakagawa, J. Ohnishi RIKEN Nishina Center, Wako, Japan
	In order to investigate the ion optical parameters of the beam line of RIKEN 28 GHz SC-ECR ion source into the new heavy ion linac (RILAC II), we measured the emittance of the heavy ion beams form RIKEN 28 GHz SC-ECR ion source. In the test experiments, we observed that the emittance of the U³⁵⁺ beam was ~100 π·mm·mrad (4 rms emittance), which is smaller than the acceptance of the accelerator (~160 π·mm·mrad). The emittance with 28 GHz was almost same as that with 18 GHz and independent on the injected RF power (1~2 kW). The size of emittance increased with decreasing the charge state. We also measured the emittance of U and oxygen ions under the same condition. In this experiment we observed that the emittance of oxygen ions was always larger than the U ion beam for same M/q. In this contribution, we report the experimental results for emittance measurement of highly charged U, Xe and O ions from RIKEN 28 GHz SC-ECR ion source in detail.

THXO03	Recent RIKEN 28 GHz SC-ECRIS Results	159
	Y. Higurashi, M. Fujimaki, H. Haba, O. Kamigaito, M. Kidera, M. Komiyama, J. Ohnishi, K. Ozeki RIKEN Nishina Center, Wako, Japan T. Aihara, M. Tamura, A. Uchiyama SHI Accelerator Service Ltd., Tokyo, Japan
	For increasing the beam intensity of highly charged heavy ions at RIKEN RIBF, we constructed new SC-ECR ion source. In the spring of 2011, we injected 28GHz microwave into the ion source and obtained first beam. Since then, we made several test experiments for increasing the beam intensity of highly charged Xe and U ion beam, and produced ~60 eμA of U³⁵⁺, ~90 eμA of U³³⁺ at the injected RF power of ~2 kW using sputtering method. In case of Xe²⁵⁺, 250 euA was obtained at RF power of 1.7 kW. Using sputtering method, we produced U³⁵⁺ ion beam longer than one month for the RIBF experiment without break. In the beginning of 2012, we installed additional GM-JT refrigerator to increase the cooling power at 4.2 K, then the total cooling power became higher than 9 W. Using it, we can use higher than 8 W of cooling power for heat load due to the absorbed X-rays. In this summer, we will install the new plasma chamber made of Al for increasing the cooling power. We will also use high temperature oven to increase the U vapor. In this contribution, we report the recent modification of the ion source and test experiments for production of U and Xe ion beam.
	Slides THXO03 [49.487 MB]