ECRIS2016 - List of Authors (Xie, D.)

Paper	Title	Page
MOBO02	Possible Optimizations of Existing Magnet Structures for the Next Generation of ECRIS	5
	D. Xie, G.L. Sabbi, D.S. Todd LBNL, Berkeley, California, USA W. Lu IMP/CAS, Lanzhou, People's Republic of China
	Constructing a minimum-B structure with higher magnetic fields is the prerequisite for the next generation of Electron Cyclotron Resonance Ion Sources (ECRIS): ion sources that will operate at substantially higher heating frequencies than those currently in use. There are three leading candidates of Nb3Sn coil structures for use in future ECRISs: a Mixed Axial and Radial field System (MARS) that merges the sextupole racetrack coils and partial end-solenoids into an exotic closed-loop-coil; a classical Sextupole-In-Solenoids design; and a Solenoids-In-Sextupole configuration. Focusing on efficient magnetic field generation, this article briefly reviews the advantages and disadvantages of each of these magnet structures. Though Sextupole-In-Solenoids and Solenoids-In-Sextupole magnetic structures using NbTi conductor have been validated by current ECRISs, improvements of these magnet structures remain possible. Possible optimizations to the two existing magnet structures, such as using a non-conventional sextupole magnet consisting of either V-bend or skew racetrack coils, are discussed. The development status of a MARS NbTi magnet at LBNL for a new ECRIS will be also presented.
	Slides MOBO02 [3.864 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2016-MOBO02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOCO04	Recent Bremsstrahlung Measurements from the Superconducting Electron Cyclotron Resonance Ion Source VENUS	23
	J.Y. Benitez, C.M. Lyneis, L. Phair, D.S. Todd, D. Xie LBNL, Berkeley, California, USA
	Axial bremsstrahlung from the superconducting Electron Cyclotron Resonance ion source VENUS have been systematically measured as a function of RF heating frequency, and the axial and radial field strengths. The work focuses on bremsstrahlung with energies greater than 10 keV to extract the spectral temperature Ts. The three axial coils and the radial coils in the superconducting VENUS can all be set independently and have a large dynamic range, which makes it possible to decouple Bmin and Bgrad and study their effects on the bremsstrahlung independently. With typical pressure and RF power levels, the measurements show that Ts depends approximately linearly on Bmin and is not correlated with the ∇BECR, the magnetic field mirror ratios or the RF frequency. These results are important for the next generation of ECR ion sources, which are designed to operate at frequencies above 40 GHz and significantly higher magnetic fields where bremsstrahlung is expected to cause a significant cryogenic heat load and increase the radiation shielding requirements.
	Slides MOCO04 [5.268 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2016-MOCO04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAO01	Recent production of intense high charge ion beams with VENUS	142
	D. Xie, J.Y. Benitez, C.M. Lyneis, D.S. Todd LBNL, Berkeley, California, USA W. Lu IMP/CAS, Lanzhou, People's Republic of China
	Several modifications have been made to the VENUS to enhance its performance at high microwave power and bring its performance closer to the levels predicted by scaling laws for 28 GHz operation. Two of these modifications improved its tolerance for operation at microwave power up to 10 kW. The cooling scheme on the plasma wall was improved to eliminate damage caused by localized electron heating. Similarly the extraction electrode was redesigned to transport away the electron heating more effectively. The third modification reduced the waveguide diameter, which launches the 28 GHz power into the plasma chamber. The source now runs efficiently at 10 kW of injected power with a more favorable magnetic field configuration. The production of intense highly charged ion beams with VENUS has been substantially enhanced. It has produced a number of record CW beams: 4.5 emA of O⁶⁺, 0.40 emA of Ar¹⁶⁺ and 0.06 emA of Ar¹⁷⁺ and for the first time the VENUS has produced more than 1 emA of Ar¹²⁺ and O⁷⁺. Source tuning is currently underway to explore the potential of VENUS and the overall improved source performance will be presented.
	Slides THAO01 [4.261 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2016-THAO01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Possible Optimizations of Existing Magnet Structures for the Next Generation of ECRIS

5

D. Xie, G.L. Sabbi, D.S. Todd
LBNL, Berkeley, California, USA
W. Lu
IMP/CAS, Lanzhou, People's Republic of China

Constructing a minimum-B structure with higher magnetic fields is the prerequisite for the next generation of Electron Cyclotron Resonance Ion Sources (ECRIS): ion sources that will operate at substantially higher heating frequencies than those currently in use. There are three leading candidates of Nb3Sn coil structures for use in future ECRISs: a Mixed Axial and Radial field System (MARS) that merges the sextupole racetrack coils and partial end-solenoids into an exotic closed-loop-coil; a classical Sextupole-In-Solenoids design; and a Solenoids-In-Sextupole configuration. Focusing on efficient magnetic field generation, this article briefly reviews the advantages and disadvantages of each of these magnet structures. Though Sextupole-In-Solenoids and Solenoids-In-Sextupole magnetic structures using NbTi conductor have been validated by current ECRISs, improvements of these magnet structures remain possible. Possible optimizations to the two existing magnet structures, such as using a non-conventional sextupole magnet consisting of either V-bend or skew racetrack coils, are discussed. The development status of a MARS NbTi magnet at LBNL for a new ECRIS will be also presented.

Slides MOBO02 [3.864 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2016-MOBO02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOCO04

Recent Bremsstrahlung Measurements from the Superconducting Electron Cyclotron Resonance Ion Source VENUS

23

J.Y. Benitez, C.M. Lyneis, L. Phair, D.S. Todd, D. Xie
LBNL, Berkeley, California, USA

Axial bremsstrahlung from the superconducting Electron Cyclotron Resonance ion source VENUS have been systematically measured as a function of RF heating frequency, and the axial and radial field strengths. The work focuses on bremsstrahlung with energies greater than 10 keV to extract the spectral temperature Ts. The three axial coils and the radial coils in the superconducting VENUS can all be set independently and have a large dynamic range, which makes it possible to decouple Bmin and Bgrad and study their effects on the bremsstrahlung independently. With typical pressure and RF power levels, the measurements show that Ts depends approximately linearly on Bmin and is not correlated with the ∇BECR, the magnetic field mirror ratios or the RF frequency. These results are important for the next generation of ECR ion sources, which are designed to operate at frequencies above 40 GHz and significantly higher magnetic fields where bremsstrahlung is expected to cause a significant cryogenic heat load and increase the radiation shielding requirements.

Slides MOCO04 [5.268 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2016-MOCO04

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAO01

Recent production of intense high charge ion beams with VENUS

142

D. Xie, J.Y. Benitez, C.M. Lyneis, D.S. Todd
LBNL, Berkeley, California, USA
W. Lu
IMP/CAS, Lanzhou, People's Republic of China

Several modifications have been made to the VENUS to enhance its performance at high microwave power and bring its performance closer to the levels predicted by scaling laws for 28 GHz operation. Two of these modifications improved its tolerance for operation at microwave power up to 10 kW. The cooling scheme on the plasma wall was improved to eliminate damage caused by localized electron heating. Similarly the extraction electrode was redesigned to transport away the electron heating more effectively. The third modification reduced the waveguide diameter, which launches the 28 GHz power into the plasma chamber. The source now runs efficiently at 10 kW of injected power with a more favorable magnetic field configuration. The production of intense highly charged ion beams with VENUS has been substantially enhanced. It has produced a number of record CW beams: 4.5 emA of O⁶⁺, 0.40 emA of Ar¹⁶⁺ and 0.06 emA of Ar¹⁷⁺ and for the first time the VENUS has produced more than 1 emA of Ar¹²⁺ and O⁷⁺. Source tuning is currently underway to explore the potential of VENUS and the overall improved source performance will be presented.

Slides THAO01 [4.261 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2016-THAO01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)