ECRIS2010 - List of Authors (Zhao, H.W.)

Paper

Title

Page

SECRAL Status and First Beam Test at 24GHz

1

H.W. Zhao, Y. Cao, Y.C. Feng, X.H. Guo, J.Y. Li, W. Lu, L.T. Sun, D. Xie, X.Z. Zhang, H. Zhao
IMP, Lanzhou, People's Republic of China

SECRAL has been in routine operation at 18GHz for HIRFL (Heavy Ion Research Facility in Lanzhou) accelerator complex since May 2007. It has delivered many highly charged heavy ion beams for the HIRFL accelerator and the total beam time so far has exceeded 3000 hours. To further enhance the SECRAL performance, a 24GHz/7kW gyrotron microwave amplifier has been installed and tested. Very exciting results were produced with quite a few new record highly-charged ion beam intensities. Bremstrahlung measurements at 24GHz have shown that X-ray is much stronger at higher RF frequency, higher RF power and higher minimum B field. Beam emittance study has been conducted in order to improve the beam brightness. An additional cryostat with five GM cryocoolers was installed atop the SECRAL to liquefy the boil-off helium gas to minimize the liquid helium consumption. The latest results and reliable long-term operation for the accelerator have once again demonstrated that SECRAL is one of the best performance ECR ion source for the production of highly-charged heavy ion beams. Detailed and future developments of SECRAL will be presented.

Slides MOCOAK01 [4.739 MB]

MOCOCK03

Design Study of a Higher Magnetic Field SC ECRIS at IMP

30

D. Xie, W. Lu, X.Z. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

Development of ECR ion source has demonstrated that, as the empirical scaling laws summarized, higher magnetic field with higher operation frequencies will greatly improve the source performance. Based on the great success of SECRAL, a higher magnetic field SC ECRIS is planned to meet the new accelerator demands at IMP. However, there are many practical issues in the design and construction of a higher field SC ECRIS that need to be addressed. In this paper we will present and discuss the design features of the higher field SC ECR with a maximum axial field of 7.0 T and a radial field of 3.5 T at the plasma chamber inner surface, and operating frequency up to 50 GHz.

Slides MOCOCK03 [1.825 MB]

MOPOT011

DRAGON: a New 18 GHz RT ECR Ion Source with a Large Plasma Chamber

58

W. Lu, D. Xie, X.Z. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China
W. Lu
Graduate School of the Chinese Academy of Sciences, Beijing, People's Republic of China
L. Ruan, F.C. Song, B. Xiong, S. Yu, J. Yuan
IEE, Beijing, People's Republic of China

Building a strong radial magnetic field with a permanent hexapole magnet for an ECRIS is extremely challenging so that the conventional wisdom requires a small but not optimal plasma chamber that is typically of ID less or equal to 80 mm. A new 18 GHz RT ECR ion source, DRAGON, has been designed with a large bore permanent hexapole and source construction has begun at IMP. Its plasma chamber is of ID of 126 mm, the same as that of the superconducting ion source SECRAL, with maximum radial field strength reaching 1.5 Tesla at the plasma chamber wall. The overall magnetic strengths of DRAGON, with maximum axial fields of 2.7 Tesla at the injection and 1.3 Tesla at the extraction, are very similar to those of SECRAL operating at 18 GHz and hopefully the SECRAL performance. The source solenoid magnet coils are cooled by an evaporative coolant at about 50 degree C. In addition, the source is thickly insulated for beam extraction at 50 kV and higher voltage up to 100 kV can be explored. This article will present the design details and discussions of this new ion source.

Poster MOPOT011 [0.563 MB]

TUPOT009

Measurements of Bremsstrahlung Radiation and X-Ray Heat Load to Cryostat on SECRAL

134

H. Zhao, Y. Cao, X.X. Li, D. Xie, W.H. Zhang, X.Z. Zhang, H.W. Zhao, Y.H. Zhu
IMP, Lanzhou, People's Republic of China
W. Lu
Graduate School of the Chinese Academy of Sciences, Beijing, People's Republic of China

Measurement of Bremsstrahlung radiation from ECR plasma can yield certain information of the ECR heating process and a plausible estimate of the X-ray heat load to the cryostat of a superconducting ECR source which needs seriously addressed. With a newly-developed collimation system, which defines a narrower spatial range of the measurement and provides an effective shielding from the background, a systematic measurement of the Bremmstrahlung emitted axially from the SECRAL (Superconducting ECR Ion Source with Advanced design in Lanzhou) plasma were carried out recently. The spectral temperature Tspe, a relative index of mean energy of the plasma hot electrons, was derived through linear fitting of the spectra in semi-logarithm coordinates. This article will present and discuss the evolutions of the X-ray flux and the hot electron energy with various source parameters, such as heating frequency, RF power and magnetic field configuration. And possible solutions to reduce the X-ray heat load induced by Bremsstrahlung radiation are proposed and discussed.

Poster TUPOT009 [1.581 MB]

Paper	Title	Page
MOCOAK01	SECRAL Status and First Beam Test at 24GHz	1
	H.W. Zhao, Y. Cao, Y.C. Feng, X.H. Guo, J.Y. Li, W. Lu, L.T. Sun, D. Xie, X.Z. Zhang, H. Zhao IMP, Lanzhou, People's Republic of China
	SECRAL has been in routine operation at 18GHz for HIRFL (Heavy Ion Research Facility in Lanzhou) accelerator complex since May 2007. It has delivered many highly charged heavy ion beams for the HIRFL accelerator and the total beam time so far has exceeded 3000 hours. To further enhance the SECRAL performance, a 24GHz/7kW gyrotron microwave amplifier has been installed and tested. Very exciting results were produced with quite a few new record highly-charged ion beam intensities. Bremstrahlung measurements at 24GHz have shown that X-ray is much stronger at higher RF frequency, higher RF power and higher minimum B field. Beam emittance study has been conducted in order to improve the beam brightness. An additional cryostat with five GM cryocoolers was installed atop the SECRAL to liquefy the boil-off helium gas to minimize the liquid helium consumption. The latest results and reliable long-term operation for the accelerator have once again demonstrated that SECRAL is one of the best performance ECR ion source for the production of highly-charged heavy ion beams. Detailed and future developments of SECRAL will be presented.
	Slides MOCOAK01 [4.739 MB]

MOCOCK03	Design Study of a Higher Magnetic Field SC ECRIS at IMP	30
	D. Xie, W. Lu, X.Z. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	Development of ECR ion source has demonstrated that, as the empirical scaling laws summarized, higher magnetic field with higher operation frequencies will greatly improve the source performance. Based on the great success of SECRAL, a higher magnetic field SC ECRIS is planned to meet the new accelerator demands at IMP. However, there are many practical issues in the design and construction of a higher field SC ECRIS that need to be addressed. In this paper we will present and discuss the design features of the higher field SC ECR with a maximum axial field of 7.0 T and a radial field of 3.5 T at the plasma chamber inner surface, and operating frequency up to 50 GHz.
	Slides MOCOCK03 [1.825 MB]

MOPOT011	DRAGON: a New 18 GHz RT ECR Ion Source with a Large Plasma Chamber	58
	W. Lu, D. Xie, X.Z. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China W. Lu Graduate School of the Chinese Academy of Sciences, Beijing, People's Republic of China L. Ruan, F.C. Song, B. Xiong, S. Yu, J. Yuan IEE, Beijing, People's Republic of China
	Building a strong radial magnetic field with a permanent hexapole magnet for an ECRIS is extremely challenging so that the conventional wisdom requires a small but not optimal plasma chamber that is typically of ID less or equal to 80 mm. A new 18 GHz RT ECR ion source, DRAGON, has been designed with a large bore permanent hexapole and source construction has begun at IMP. Its plasma chamber is of ID of 126 mm, the same as that of the superconducting ion source SECRAL, with maximum radial field strength reaching 1.5 Tesla at the plasma chamber wall. The overall magnetic strengths of DRAGON, with maximum axial fields of 2.7 Tesla at the injection and 1.3 Tesla at the extraction, are very similar to those of SECRAL operating at 18 GHz and hopefully the SECRAL performance. The source solenoid magnet coils are cooled by an evaporative coolant at about 50 degree C. In addition, the source is thickly insulated for beam extraction at 50 kV and higher voltage up to 100 kV can be explored. This article will present the design details and discussions of this new ion source.
	Poster MOPOT011 [0.563 MB]

TUPOT009	Measurements of Bremsstrahlung Radiation and X-Ray Heat Load to Cryostat on SECRAL	134
	H. Zhao, Y. Cao, X.X. Li, D. Xie, W.H. Zhang, X.Z. Zhang, H.W. Zhao, Y.H. Zhu IMP, Lanzhou, People's Republic of China W. Lu Graduate School of the Chinese Academy of Sciences, Beijing, People's Republic of China
	Measurement of Bremsstrahlung radiation from ECR plasma can yield certain information of the ECR heating process and a plausible estimate of the X-ray heat load to the cryostat of a superconducting ECR source which needs seriously addressed. With a newly-developed collimation system, which defines a narrower spatial range of the measurement and provides an effective shielding from the background, a systematic measurement of the Bremmstrahlung emitted axially from the SECRAL (Superconducting ECR Ion Source with Advanced design in Lanzhou) plasma were carried out recently. The spectral temperature Tspe, a relative index of mean energy of the plasma hot electrons, was derived through linear fitting of the spectra in semi-logarithm coordinates. This article will present and discuss the evolutions of the X-ray flux and the hot electron energy with various source parameters, such as heating frequency, RF power and magnetic field configuration. And possible solutions to reduce the X-ray heat load induced by Bremsstrahlung radiation are proposed and discussed.
	Poster TUPOT009 [1.581 MB]