Development of series H− multicusp ion source at China Institute of Atomic Energya) Zhang TianJue, Jia XianLu, Li ZhenGuo, Lu Yinlong, Qin JiuChang, Zheng Xia, Yao Hongjuan, Zhong JunQing, Pan GaoFeng, Ge Tao, and Guan Fengping Citation: Review of Scientific Instruments 85, 02B110 (2014); doi: 10.1063/1.4832675 View online: http://dx.doi.org/10.1063/1.4832675 View Table of Contents: http://scitation.aip.org/content/aip/journal/rsi/85/2?ver=pdfcov Published by the AIP Publishing Articles you may be interested in Experimental development on the 18 mA, H− multi-cusp ion source at China Institute of Atomic Energya) Rev. Sci. Instrum. 83, 02A726 (2012); 10.1063/1.3678654 Development of an H − ion source for Japan Proton Accelerator Research Complex upgradea) Rev. Sci. Instrum. 81, 02A716 (2010); 10.1063/1.3277140 New developments in multicusp H − ion sources for high energy accelerators (invited)a) Rev. Sci. Instrum. 79, 02A515 (2008); 10.1063/1.2801647 ECRDriven Multicusp Volume H− Ion Source AIP Conf. Proc. 763, 203 (2005); 10.1063/1.1908296 Development of a H − ion source for the high intensity proton linac at Japan Atomic Energy Research Institute Rev. Sci. Instrum. 71, 975 (2000); 10.1063/1.1150363
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REVIEW OF SCIENTIFIC INSTRUMENTS 85, 02B110 (2014)
Development of series H− multicusp ion source at China Institute of Atomic Energya) Zhang TianJue, Jia XianLu,b) Li ZhenGuo, Lu Yinlong, Qin JiuChang, Zheng Xia, Yao Hongjuan, Zhong JunQing, Pan GaoFeng, Ge Tao, and Guan Fengping China Institute of Atomic Energy, Beijing, China
(Presented 10 September 2013; received 7 September 2013; accepted 13 October 2013; published online 25 November 2013) The development of H− multicusp ion sources has been carried out at China Institute of Atomic Energy (CIAE) for more than ten years. The first H− ion source with 5.2 mA was made in 2002. After improving the configured magnetic field, a H− ion source of 10 mA was made in 2004, and the beam intensity of 15 mA was obtained in 2008 after further improvements of the filter field. The beam intensity of 18 mA was achieved in 2010 following the in-depth study and optimization on some essential operation conditions. Now a series of H− cusp sources with different sizes and beam intensity ranging from 3 mA to 18 mA have been successfully developed at CIAE. All the ion sources can fast finish the test on the test stand now, since all the connections are modularized and can fit all kinds of H− mulitcusp source of CIAE. The development status of the various H− multicusp ion sources at CIAE are presented in the paper. © 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4832675] I. INTRODUCTION
Since H− multicusp ion sources have different uses at China Institute of Atomic Energy (CIAE), such as Positron Emission Tomography (PET), special scientific research, the Beijing Radioactive Ion-beam Facility (BRIF), a series of H− multicusp ion sources with different sizes, beam ranging from 3 mA to 18 mA, have been successfully developed at CIAE. All these ion sources have been tested in one test stand, which can fit different sizes of ion sources by an adapter flange. And all the cooling water and electricity tie-in of the test stand are modularized. CIAE has devoted to the development of the H− multicusp ion source since 2002, and an ion source was built with an average beam intensity of 5.2 mA. In 2003, another H− ion source was built with a beam intensity of higher than 10 mA with an emittance of 0.65 π mm mrad.1 In order to increase the beam intensity and to satisfy the need of the BRIF, a new ion source was built based on the 10 mA source, and achieved 15 mA H− beam in 2008.2 After some measures to improve the ion source, a beam of 18 mA H− can be obtained from the source with a beam emittance of 0.93 π mm mrad.3 II. EXPERIMENTAL SETUP
The H− multicusp ion source is mounted on an ion source test stand which operates up to 40 kV, as shown in Fig. 1. A gas analysis apparatus is installed on the vacuum box to analyze the gas content in the ion source body after inputting H2 gas. Using the adapter flange with different inner diameter, the different sizes of ion source can be tested on the test stand. And the beam emittance is measured by Allison scanner with the double slits structure. a) Contributed paper, published as part of the Proceedings of the 15th
International Conference on Ion Sources, Chiba, Japan, September 2013. b) Electronic mail: [email protected]
0034-6748/2014/85(2)/02B110/3/$30.00
To reasonably improve the vacuum of the extraction area is significant influence on the H− beam intensity. Taking into consideration the electrode configuration and the insulating material, we design the vacuum box as two parts, an ion source vacuum box and a beam diagnostic box. The upper part is connected to the ion source, and there are two 1300 l/s turbo-pump in place to improve vacuum of ion source extraction area. The lower part which connects the beam pipe is used to install Faraday cup and emittance scanner, and there is a 700 l/s turbo-pump for this area vacuum. The two parts are connected only by a ground electrode with a diameter of 13 mm.4
III. DEVELOPMENT OF THE ION SOURCES
In 2000, 5.2 mA of H− beam with a normalized emittance ∼0.65 π mm mrad was obtained. To get higher beam intensity and keep the emittance within the desired value from the cyclotron design, a new cusp source was built at CIAE based on TRIUMF’s experience5 in 2003. In this ion source, the multicusp filed and the virtual filter filed is increased, and the cooling water system was also modified to improve cooling on key parts of the ion source, e.g., filament stems, cavity wall, extractor, and ground electrodes. Then a beam intensity of 11 mA with an emittance of 0.65 π mm mrad was achieved. To improve the performance of our H− source and meet the need of the H− beam injection for a 100 MeV compact cyclotron under construction at CIAE, a multicusp source had been built to produce 15 mA H− DC beam.2 Major efforts include the study of the virtual filter magnetic field, confining magnetic field, filament shape and location, the vacuum improvement in the extracting area, the extraction optics, and new control and interlock system of the power supplies. And some experiments had been performed, including changing the different plasma apertures (from 8 mm to 13 mm), filament (single and double rings), arc power, gas flow, etc. As a
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Rev. Sci. Instrum. 85, 02B110 (2014) TABLE I. The example parameters for 15 mA ion source. Filament Arc Plasma Lens Extraction Beam intensity
FIG. 1. The schematic diagram of H− ion source test stand.
consequence, more than 15 mA of H− beam was obtained stably with the double rings filament, plasma aperture of 13 mm, and arc power of ∼3.6 kW. The stability test of the extracted beam for over 36 h was implemented at 15 mA with beam stability of ±0.5%. The normalized emittance of 0.48 π mm mrad (4 rms normalized emittance) was measured under ∼8 mA DC beam. In 2010, 18 mA H− ion beam with emittance of 0.93 π mm mrad was obtained from this ion source through the in-depth study and optimization on some essential parameters affecting the beam intensity and quality. IV. A SERIES OF ION SOURCES
In order to meet different requirements of CIAE, a series of H− multicusp ion sources with different sizes, beam ranging from 3 mA to 18 mA, have been successfully developed at CIAE, which are CIAE-CH-I, CIAE-CH-II, and CIAE-CHIII type, as shown in Fig. 2
56.3 A/2.73 V 52.9 A/70.5 V 11.6 A/3.1 V 89 mA/4.16 lV 31.2 mA/35.1 kV 15.4 mA
tensity beam, which is different from the most medical cyclotrons with internal ion source. The H− ion source is a multicusp H− ion source, with the outer size of only 100 mm × 100 mm.6 A special shape filament, the 10 columns of permanent magnets providing a multi-cusp field, and a three electrode extraction system are adopted in the ion source with diameter of 48 mm and length of 79.5 mm. When the extracted voltage of the ion source is up to 25 kV, the maximum H− beam intensity is 3.1 mA, and the beam stability is 1% at 1 mA, 2 mA, and 2.5 mA. The normalized emittance at 2.5 mA is 0.3 π mm mrad.
B. CIAE-CH-II type
For some special scientific research, ∼8 mA H− ion source is needed. The CIAE-CH-II type ion source is designed with the plasma chamber size of diameter 75 mm and length 127 mm. Ten rows and five segments of permanent magnets (Nd-Fe-B material) with the size of 10 mm × 15 mm are placed in parallel outside of the plasma chamber creating a multicusp field. 3 mA H− beam is obtained at the first experiment. After optimization the filter field intensity and distribution, the maximum beam intensity of 9.1 mA is achieved. The stability calculated from the online record data is better than ±0.52% and the normalized emittance of the extracted beam is 0.52 π mm mrad at 8.1 mA.
A. CIAE-CH-I type
In recent years, given the fast increasing domestic demand for PET cyclotrons in China,1 a 14 MeV PET cyclotron (CYCIAE-14) is being constructed at CIAE. An external H− ion source was used on CYCIAE-14 to extract high in-
FIG. 2. Different types of ion sources.
FIG. 3. The emittance of 0.48 π mm mrad at 8 mA.
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Rev. Sci. Instrum. 85, 02B110 (2014)
TABLE II. Some measured normalized emittances under different beam intensities. Beam density (mA) Normal emittance (π mm mrad) Beam density (mA) Normal emittance (π mm mrad)
3 0.28 7 0.43
4 0.33 8 0.5
5 0.35 9 0.53
6 0.38 10 0.55
C. CIAE-CH-III type
The introduction of the CIAE-CH-III type ion source has been given in Sec. III. The source assembly consists of a tubular plasma chamber (inner diameter: 98 mm; length: 152 mm) with ten columns of permanent magnets (Nd-Fe-B material) to provide a stronger multicusp field and serves as a virtual filter, a three electrode extraction system, and a top cover with a confinement magnet inside. Now, 15 mA H− beam can be extracted from the ion source with a plasma electrode aperture of 13 mm under an arc power of 3.6 kW. The example parameters for 15 mA are shown in Table I. The stability of H− ion beam at 15 mA was measured for 36 continuous hours, with an instability of up to ±0.5%. The maximum current of the ion source is 18 mA with a normalized emittance of 0.93 π mm mrad. As an example, 0.48 π mm mrad (4 rms normalized emittance) is measured with ∼8 mA DC beam for type-III, as is shown in Fig. 3.
Some measured normalized emittances under different beam intensities are shown in Table II. V. CONCLUSION
A series of ion sources have been developed at CIAE, and all these ion sources could satisfy the different cyclotrons for different source sizes and beam intensities. The upgrade of the extraction structure is being carried on and it is planned to get better H− beam quality in the latter half of this year. ACKNOWLEDGMENTS
The authors are very much grateful to Dr. D. Yuan and T. Kuo for their helpful discussion and visiting of CIAE’s accelerator laboratory when the source was tested. 1 T.
Zhang, Z. Li, C. Chu, L. Wu, J. Zhong, C. Jiao, T. Ge, G. Pan, and F. Guan, Rev. Sci. Instrum. 75, 1854 (2004). 2 T. Zhang, X. Jia, Y. Lv, J. Zou, F. Guan, L. Wu, G. Pan, G. Liu, J. Lin, T. Ge, H. Yao, Z. Wang, and S. An, Rev. Sci. Instrum. 81, 02A705 (2010). 3 T. Zhang, X. Jia, J. Qin, Y. Lv, and X. Zheng, Rev. Sci. Instrum. 83, 02A726 (2012). 4 X. Jia, T. Zhang, X. Zheng, S. Zhang, J. Zou, and J. Lin, Rev. Sci. Instrum. 81, 02A712 (2010). 5 T. Kuo, D. Yuan, K. Jayamanna, M. McDonald, R. Baartman, W. Z. Gelbart, N. Stevenson, P. Schmor, and G. Dutto, Rev. Sci. Instrum. 69, 959 (1998). 6 X. Jia, T. Zhang, X. Zheng, and J. Qin, Rev. Sci. Instrum. 83, 02A730 (2012).
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REVIEW OF SCIENTIFIC INSTRUMENTS 85, 02B110 (2014)
Development of series H− multicusp ion source at China Institute of Atomic Energya) Zhang TianJue, Jia XianLu,b) Li ZhenGuo, Lu Yinlong, Qin JiuChang, Zheng Xia, Yao Hongjuan, Zhong JunQing, Pan GaoFeng, Ge Tao, and Guan Fengping China Institute of Atomic Energy, Beijing, China
(Presented 10 September 2013; received 7 September 2013; accepted 13 October 2013; published online 25 November 2013) The development of H− multicusp ion sources has been carried out at China Institute of Atomic Energy (CIAE) for more than ten years. The first H− ion source with 5.2 mA was made in 2002. After improving the configured magnetic field, a H− ion source of 10 mA was made in 2004, and the beam intensity of 15 mA was obtained in 2008 after further improvements of the filter field. The beam intensity of 18 mA was achieved in 2010 following the in-depth study and optimization on some essential operation conditions. Now a series of H− cusp sources with different sizes and beam intensity ranging from 3 mA to 18 mA have been successfully developed at CIAE. All the ion sources can fast finish the test on the test stand now, since all the connections are modularized and can fit all kinds of H− mulitcusp source of CIAE. The development status of the various H− multicusp ion sources at CIAE are presented in the paper. © 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4832675] I. INTRODUCTION
Since H− multicusp ion sources have different uses at China Institute of Atomic Energy (CIAE), such as Positron Emission Tomography (PET), special scientific research, the Beijing Radioactive Ion-beam Facility (BRIF), a series of H− multicusp ion sources with different sizes, beam ranging from 3 mA to 18 mA, have been successfully developed at CIAE. All these ion sources have been tested in one test stand, which can fit different sizes of ion sources by an adapter flange. And all the cooling water and electricity tie-in of the test stand are modularized. CIAE has devoted to the development of the H− multicusp ion source since 2002, and an ion source was built with an average beam intensity of 5.2 mA. In 2003, another H− ion source was built with a beam intensity of higher than 10 mA with an emittance of 0.65 π mm mrad.1 In order to increase the beam intensity and to satisfy the need of the BRIF, a new ion source was built based on the 10 mA source, and achieved 15 mA H− beam in 2008.2 After some measures to improve the ion source, a beam of 18 mA H− can be obtained from the source with a beam emittance of 0.93 π mm mrad.3 II. EXPERIMENTAL SETUP
The H− multicusp ion source is mounted on an ion source test stand which operates up to 40 kV, as shown in Fig. 1. A gas analysis apparatus is installed on the vacuum box to analyze the gas content in the ion source body after inputting H2 gas. Using the adapter flange with different inner diameter, the different sizes of ion source can be tested on the test stand. And the beam emittance is measured by Allison scanner with the double slits structure. a) Contributed paper, published as part of the Proceedings of the 15th
International Conference on Ion Sources, Chiba, Japan, September 2013. b) Electronic mail: [email protected]
0034-6748/2014/85(2)/02B110/3/$30.00
To reasonably improve the vacuum of the extraction area is significant influence on the H− beam intensity. Taking into consideration the electrode configuration and the insulating material, we design the vacuum box as two parts, an ion source vacuum box and a beam diagnostic box. The upper part is connected to the ion source, and there are two 1300 l/s turbo-pump in place to improve vacuum of ion source extraction area. The lower part which connects the beam pipe is used to install Faraday cup and emittance scanner, and there is a 700 l/s turbo-pump for this area vacuum. The two parts are connected only by a ground electrode with a diameter of 13 mm.4
III. DEVELOPMENT OF THE ION SOURCES
In 2000, 5.2 mA of H− beam with a normalized emittance ∼0.65 π mm mrad was obtained. To get higher beam intensity and keep the emittance within the desired value from the cyclotron design, a new cusp source was built at CIAE based on TRIUMF’s experience5 in 2003. In this ion source, the multicusp filed and the virtual filter filed is increased, and the cooling water system was also modified to improve cooling on key parts of the ion source, e.g., filament stems, cavity wall, extractor, and ground electrodes. Then a beam intensity of 11 mA with an emittance of 0.65 π mm mrad was achieved. To improve the performance of our H− source and meet the need of the H− beam injection for a 100 MeV compact cyclotron under construction at CIAE, a multicusp source had been built to produce 15 mA H− DC beam.2 Major efforts include the study of the virtual filter magnetic field, confining magnetic field, filament shape and location, the vacuum improvement in the extracting area, the extraction optics, and new control and interlock system of the power supplies. And some experiments had been performed, including changing the different plasma apertures (from 8 mm to 13 mm), filament (single and double rings), arc power, gas flow, etc. As a
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02B110-2
TianJue et al.
Rev. Sci. Instrum. 85, 02B110 (2014) TABLE I. The example parameters for 15 mA ion source. Filament Arc Plasma Lens Extraction Beam intensity
FIG. 1. The schematic diagram of H− ion source test stand.
consequence, more than 15 mA of H− beam was obtained stably with the double rings filament, plasma aperture of 13 mm, and arc power of ∼3.6 kW. The stability test of the extracted beam for over 36 h was implemented at 15 mA with beam stability of ±0.5%. The normalized emittance of 0.48 π mm mrad (4 rms normalized emittance) was measured under ∼8 mA DC beam. In 2010, 18 mA H− ion beam with emittance of 0.93 π mm mrad was obtained from this ion source through the in-depth study and optimization on some essential parameters affecting the beam intensity and quality. IV. A SERIES OF ION SOURCES
In order to meet different requirements of CIAE, a series of H− multicusp ion sources with different sizes, beam ranging from 3 mA to 18 mA, have been successfully developed at CIAE, which are CIAE-CH-I, CIAE-CH-II, and CIAE-CHIII type, as shown in Fig. 2
56.3 A/2.73 V 52.9 A/70.5 V 11.6 A/3.1 V 89 mA/4.16 lV 31.2 mA/35.1 kV 15.4 mA
tensity beam, which is different from the most medical cyclotrons with internal ion source. The H− ion source is a multicusp H− ion source, with the outer size of only 100 mm × 100 mm.6 A special shape filament, the 10 columns of permanent magnets providing a multi-cusp field, and a three electrode extraction system are adopted in the ion source with diameter of 48 mm and length of 79.5 mm. When the extracted voltage of the ion source is up to 25 kV, the maximum H− beam intensity is 3.1 mA, and the beam stability is 1% at 1 mA, 2 mA, and 2.5 mA. The normalized emittance at 2.5 mA is 0.3 π mm mrad.
B. CIAE-CH-II type
For some special scientific research, ∼8 mA H− ion source is needed. The CIAE-CH-II type ion source is designed with the plasma chamber size of diameter 75 mm and length 127 mm. Ten rows and five segments of permanent magnets (Nd-Fe-B material) with the size of 10 mm × 15 mm are placed in parallel outside of the plasma chamber creating a multicusp field. 3 mA H− beam is obtained at the first experiment. After optimization the filter field intensity and distribution, the maximum beam intensity of 9.1 mA is achieved. The stability calculated from the online record data is better than ±0.52% and the normalized emittance of the extracted beam is 0.52 π mm mrad at 8.1 mA.
A. CIAE-CH-I type
In recent years, given the fast increasing domestic demand for PET cyclotrons in China,1 a 14 MeV PET cyclotron (CYCIAE-14) is being constructed at CIAE. An external H− ion source was used on CYCIAE-14 to extract high in-
FIG. 2. Different types of ion sources.
FIG. 3. The emittance of 0.48 π mm mrad at 8 mA.
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Rev. Sci. Instrum. 85, 02B110 (2014)
TABLE II. Some measured normalized emittances under different beam intensities. Beam density (mA) Normal emittance (π mm mrad) Beam density (mA) Normal emittance (π mm mrad)
3 0.28 7 0.43
4 0.33 8 0.5
5 0.35 9 0.53
6 0.38 10 0.55
C. CIAE-CH-III type
The introduction of the CIAE-CH-III type ion source has been given in Sec. III. The source assembly consists of a tubular plasma chamber (inner diameter: 98 mm; length: 152 mm) with ten columns of permanent magnets (Nd-Fe-B material) to provide a stronger multicusp field and serves as a virtual filter, a three electrode extraction system, and a top cover with a confinement magnet inside. Now, 15 mA H− beam can be extracted from the ion source with a plasma electrode aperture of 13 mm under an arc power of 3.6 kW. The example parameters for 15 mA are shown in Table I. The stability of H− ion beam at 15 mA was measured for 36 continuous hours, with an instability of up to ±0.5%. The maximum current of the ion source is 18 mA with a normalized emittance of 0.93 π mm mrad. As an example, 0.48 π mm mrad (4 rms normalized emittance) is measured with ∼8 mA DC beam for type-III, as is shown in Fig. 3.
Some measured normalized emittances under different beam intensities are shown in Table II. V. CONCLUSION
A series of ion sources have been developed at CIAE, and all these ion sources could satisfy the different cyclotrons for different source sizes and beam intensities. The upgrade of the extraction structure is being carried on and it is planned to get better H− beam quality in the latter half of this year. ACKNOWLEDGMENTS
The authors are very much grateful to Dr. D. Yuan and T. Kuo for their helpful discussion and visiting of CIAE’s accelerator laboratory when the source was tested. 1 T.
Zhang, Z. Li, C. Chu, L. Wu, J. Zhong, C. Jiao, T. Ge, G. Pan, and F. Guan, Rev. Sci. Instrum. 75, 1854 (2004). 2 T. Zhang, X. Jia, Y. Lv, J. Zou, F. Guan, L. Wu, G. Pan, G. Liu, J. Lin, T. Ge, H. Yao, Z. Wang, and S. An, Rev. Sci. Instrum. 81, 02A705 (2010). 3 T. Zhang, X. Jia, J. Qin, Y. Lv, and X. Zheng, Rev. Sci. Instrum. 83, 02A726 (2012). 4 X. Jia, T. Zhang, X. Zheng, S. Zhang, J. Zou, and J. Lin, Rev. Sci. Instrum. 81, 02A712 (2010). 5 T. Kuo, D. Yuan, K. Jayamanna, M. McDonald, R. Baartman, W. Z. Gelbart, N. Stevenson, P. Schmor, and G. Dutto, Rev. Sci. Instrum. 69, 959 (1998). 6 X. Jia, T. Zhang, X. Zheng, and J. Qin, Rev. Sci. Instrum. 83, 02A730 (2012).
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