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H W Zhao,
L T Sun,
W Lu,
X Z Zhang,
X H Guo,
Y Cao,
H Y Zhao,
Y C Feng,
J Y Li,
H Y Ma, Y Shang,
B H Ma,
H Wang,
X X Li,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18-28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e microA of (129)Xe(43+), 22 e microA of (209)Bi(41+), and 1.5 e microA of (209)Bi(50+). To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e microA of (129)Xe(27+) and 152 e microA of (129)Xe(30+), although the commissioning time was limited within 3-4 weeks and rf power only 3-4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and (129)Xe(27+), (78)Kr(19+), (209)Bi(31+), and (58)Ni(19+) beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of ECR ion source for highly charged heavy ion beam production. Finally the future development of SECRAL will be presented.
The Review of scientific instruments 02/2010; 81(2):02A202. · 1.52 Impact Factor
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L T Sun,
H W Zhao,
W Lu,
X Z Zhang,
Y C Feng,
J Y Li,
Y Cao,
X H Guo,
H Y Ma,
H Y Zhao, Y Shang,
B H Ma,
H Wang,
X X Li,
T Jin,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e microA of Xe(37+), 1 e microA of Xe(43+), and 0.16 e microA of Ne-like Xe(44+). To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi(31+) beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e microA of Bi(31+), 22 e microA of Bi(41+), and 1.5 e microA of Bi(50+) have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.
The Review of scientific instruments 02/2010; 81(2):02A318. · 1.52 Impact Factor
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H Y Zhao,
H W Zhao,
L T Sun,
H Wang,
D Z Xie,
B H Ma,
X Zh Zhang,
X X Li,
X W Ma,
Y H Zhu,
W Lu, Y Shang
[show abstract]
[hide abstract]
ABSTRACT: To investigate the hot electrons in highly charged electron cyclotron resonance (ECR) plasma, Bremsstrahlung radiations were measured on two ECR ion sources at the Institute of Modern Physics. Used as a comparative index of the mean energy of the hot electrons, a spectral temperature, Tspe, is derived through a linear fitting of the spectra in a semi-logarithmic representation. The influences of the external source parameters, especially the magnetic configuration, on the hot electrons are studied systematically. This study has experimentally demonstrated the importance of high microwave frequency and high magnetic field in the electron resonance heating to produce a high density of hot electrons, which is consistent with the empirical ECR scaling laws. The experimental results have again shown that a good compromise is needed between the ion extraction and the plasma confinement for an efficient production of highly charged ion beams. In addition, this investigation has shown that the correlation between the mean energy of the hot electrons and the magnetic field gradient at the ECR is well in agreement with the theoretical models.
Plasma Sources Science and Technology 03/2009; 18(2):025021. · 2.52 Impact Factor
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H Y Zhao,
H W Zhao,
X W Ma,
H Wang,
X Z Zhang,
L T Sun,
B H Ma,
X X Li,
S Sha,
Y H Zhu,
W Lu, Y Shang
[show abstract]
[hide abstract]
ABSTRACT: In order to investigate the hot electron component in electron cyclotron resonance (ECR) plasmas, the volume bremsstrahlung spectra in the x-ray photon energy range were measured with a high-purity germanium detector on Lanzhou ECR Ion Source No. 2 Modified (LECR2M). A collimation system similar to Bernhardi's was used to focus at the central part of the plasma. The ion source was operated under various source conditions with argon; sometimes oxygen was added to enhance high charge state ion beam intensities. The spectral temperature of hot electrons T(spe) was derived from the measured bremsstrahlung spectra. The evolution of the deduced temperature of hot electrons T(spe) with the ion source parameters, such as the rf frequency, power, and the magnetic confinement configuration, was investigated.
Review of Scientific Instruments 03/2008; 79(2 Pt 2):02B504. · 1.37 Impact Factor
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H W Zhao,
L T Sun,
X Z Zhang,
X H Guo,
Y Cao,
W Lu,
Z M Zhang,
P Yuan,
M T Song,
H Y Zhao,
T Jin, Y Shang,
W L Zhan,
B W Wei,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.
Review of Scientific Instruments 03/2008; 79(2 Pt 2):02A315. · 1.37 Impact Factor
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L T Sun, Y Shang,
B H Ma,
X Z Zhang,
Y C Feng,
X X Li,
H Wang,
X H Guo,
M T Song,
H Y Zhao,
Z M Zhang,
H W Zhao,
D Z Xie
[show abstract]
[hide abstract]
ABSTRACT: To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed.
Review of Scientific Instruments 03/2008; 79(2 Pt 2):02B711. · 1.37 Impact Factor
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L T Sun,
H W Zhao,
Z M Zhang,
H Wang,
B H Ma,
X Z Zhang,
X X Li,
Y C Feng,
J Y Li,
X H Guo, Y Shang,
H Y Zhao
[show abstract]
[hide abstract]
ABSTRACT: Two high magnetic field hexapoles for electron cyclotron resonance ion source (ECRIS) have successfully fabricated to provide sufficient radial magnetic confinement to the ECR plasma. The highest magnetic field at the inner pole tip of one of the magnets exceeds 1.5 T, with the inner diameter (i.d.)=74 mm. The other hexapole magnet provides more than 1.35 T magnetic field at the inner pole tip, and the i.d. is 84 mm. In this article, we discuss the necessity to have a good radial magnetic field confinement and the importance of a Halbach hexapole to a high performance ECRIS. The way to design a high magnetic field Halbach structure hexapole and one possible solution to the self-demagnetization problem are both discussed. Based on the above discussions, two high magnetic field hexapoles have been fabricated to be utilized on two high performance ECRISs in Lanzhou. The preliminary results obtained from the two ECR ion sources are given.
Review of Scientific Instruments 06/2007; 78(5):053302. · 1.37 Impact Factor
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Z. M. Zhang,
H. W. Zhao,
L. T. Sun,
Y. Cao,
X. Z. Zhang,
X. H. Guo,
X. X. Li,
J. Y. Li,
Y. C. Feng,
H. Wang,
B. H. Ma,
H. Y. Zhao,
W. He, Y. Shang
[show abstract]
[hide abstract]
ABSTRACT: Uranium ion beams were produced from electron cyclotron resonance (ECR) ion sources by sputtering method this year at the Institute of Modern Physics. At first, we chose the Lanzhou ECR No. 3 ion source to implement the production experiment of U ion beams. Finally, 11 e μA of U28+, 5 e μA of U32+, and 1.5 e μA of U35+ were obtained. A U26+ ion beam produced by the LECR2 ion source was accelerated successfully by the cyclotron. This means that the Heavy Ion Research Facility in Lanzhou (HIRFL) has accomplished the acceleration of the ion beam of the heaviest element according to the designed parameters. The Lanzhou ECR ion source No. 2 (LECR2), which was built in 1997, has served the HIRFL for eight years and needed to be upgraded to provide more intense high charge state ion beams for HIRFL cooling storage ring. We started the upgrading project of LECR2 last year, and the modified design just has been finished.
Review of Scientific Instruments 03/2006; 77(3):03A308-03A308-3. · 1.37 Impact Factor
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L.T. Sun,
H.W. Zhao,
J.Y. Li,
H. Wang,
B.H. Ma,
Z.M. Zhang,
X.Z. Zhang,
X.H. Guo, Y. Shang,
X.X. Li,
Y.C. Feng,
Y.H. Zhu,
P.Z. Wang,
H.P. Liu,
M.T. Song,
X.W. Ma,
W.L. Zhan
[show abstract]
[hide abstract]
ABSTRACT: A 320 kV high voltage (HV) platform has been constructed at Institute of Modern Physics (IMP) to satisfy the increasing requirements of experimental studies in some heavy ion associated directions. A high charge state all-permanent magnet ECRIS-LAPECR2 has been designed and fabricated to provide intense multiple charge state ion beams (such as 1000 eμA O6+, 16.7 eμA Ar14+, 24 eμA Xe27+, etc.) for the HV platform. LAPECR2 has a dimension of ∅ 650 mm × 560 mm. The powerful 3D magnetic confinement to the ECR plasma and the optimum designed magnetic field for the operation at 14.5 GHz makes it possible to obtain very good performances from this source. After a brief introduction of the ECRIS and accelerator development at IMP, the conceptual design of LAPECR2 source is presented. The first test results of this all-permanent magnet ECRIS are given in this paper.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms.
