LINAC2018 - Table of Session: TUOP (Tuesday Oral Posters)

Paper	Title	Page
TUOP01	Fundamental Studies of Impurity Doping in 1.3 GHz and Higher Frequency SRF Cavities
SPWR018	use link to access more material from this paper's primary paper code
TUPO054	use link to access more material from this paper's primary paper code
	J.T. Maniscalco, P.N. Koufalis, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	As the demand for more powerful, more efficient, and smaller superconducting RF accelerators continues to increase, both impurity doping and high-frequency cavities (> 1.3 GHz) have become hot topics for fundamental research because of their potential to significantly decrease surface losses and cost respectively. In this report, we present recent experimental and theoretical results on undoped and nitrogen-doped high-frequency cavities and on alternative doping agents in traditional 1.3 GHz cavities, with a focus on understanding the fundamental science of impurity doping.
	Slides TUOP01 [1.956 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO054
About •	paper received ※ 16 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUOP02	FRIB Fast Machine Protection System: Chopper Monitor System Design
TUPO007	use link to access more material from this paper's primary paper code
	Z. Li, D. Chabot, S. Cogan, S.M. Lidia, R.C. Webber FRIB, East Lansing, USA
	Funding: Work supported by Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The Facility for Rare Isotope Beams tunes the beam power from 0 to 400KW by chopping the beam current with a beam chopper in the Low Energy Beam Transport. A chopper monitoring system is employed to verify proper chopper operation to avoid delivery of undesired high-powered beam and to inhibit beam for machine protection purposes. The system monitors the incoming beam gate time structure, the chopper switch high voltage pulses, the chopper electrode charge/discharge currents, and the status of machine protection system. It is designed to switch off the beam within tens of nanoseconds of a detected fault. Chal-lenges include a dynamic beam gate pulse structure with pulse lengths as short as 0.6 µs and high voltage power supply current pulses of ~25 ns. A high speed "integrate and hold circuit with reset", Field Program-mable Gate Array based digital control circuit and high speed ADC circuit were developed to fulfil the re-quired functions. Design approach, simulation, and test results with the beam are the focus of this paper.
	Slides TUOP02 [1.082 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO007
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUOP03	Precise Evaluation of Characteristic of the Multi-layer Thin-film Superconductor Consisting of NbN and Insulator on Pure Nb Substrate
TUPO030	use link to access more material from this paper's primary paper code
	R. Katayama, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan C.Z. Antoine CEA/IRFU, Gif-sur-Yvette, France A. Four CEA/DRF/IRFU, Gif-sur-Yvette, France H. Hayano, T. Kubo, T. Saeki KEK, Ibaraki, Japan H. Ito Sokendai, Ibaraki, Japan R. Ito, T. Nagata ULVAC, Inc, Chiba, Japan H. Oikawa Utsunomiya University, Utsunomiya, Japan
	In recent years, it has been pointed out that the maximum accelerating gradient of a superconducting RF cavity can be pushed up by coating the inner surface of the cavity with a multilayer thin-film structure that consists of alternating insulating and superconducting layers. In this structure, the principal parameter that limits the performance of the cavity is the critical magnetic field or effective Hc1 at which vortices start penetrating into the superconductor layer, and it is predicted to depend on the combination of the film thickness. We made samples that have NbN/SiO2 thin-film structure on pure Nb substrate with several thicknesses of NbN film deposited using DC magnetron sputtering method. Here, we report the measurement results of effective Hc1 of the NbN sample with a thickness of 200 nm by using the third-harmonic voltage method. In addition, we report the preliminary results to evaluate the dependence of the effective Hc1 on the thickness of the NbN film in the range 50 nm-200 nm.
	Slides TUOP03 [0.305 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO030
About •	paper received ※ 18 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUOP04	Investigation of the Surface Resistance of Niobium Between 325 MHz and 1300 MHz Using a Coaxial Half-wave Cavity
TUPO031	use link to access more material from this paper's primary paper code
	H. Park, S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA
	The Center for Accelerator Science at Old Dominion University has built a half-wave coaxial cavity () to measure the surface resistance of niobium as a function of frequency, temperature, rf field, preparation techniques, over a wide range of frequencies of interest for particle accelerators. The characteristics of the half-wave coaxial cavity provide these information on a same surface. The preliminary results showed clearly the frequency dependence of residual surface resistance (). After establishing baseline, we have conducted a study of low temperature baking effect on the surface resistance under controlled environment. This paper will describe the details of the test procedure, results and we will explore underlying physics of the phenomenon. H. Park et al., MOPB003, Proc. SRF2015, http://jacow.org/ ** H. Park et al., THPB080, Proc. SRF2017, http://jacow.org/
	Slides TUOP04 [0.966 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO031
About •	paper received ※ 17 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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TUOP05	Cryogenic Test Results of the SPS Prototype RF-dipole Crabbing Cavity with Higher Order Mode Couplers
TUPO033	use link to access more material from this paper's primary paper code
	S.U. De Silva, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA Z. Li SLAC, Menlo Park, California, USA H. Park JLab, Newport News, Virginia, USA
	The rf-dipole crabbing cavity planned for the LHC High Luminosity Upgrade is designed to deliver a transverse kick of 3.34 MV; crabbing the proton beam in the horizontal plane. The proton beams of the LHC machine operating at 7 TeV each sets high impedance thresholds on the crabbing cavity systems. The rf-dipole crabbing cavity is designed with a two higher order mode couplers to suppress those HOMs. The first prototype of the HOM couplers are fabricated at Jefferson Lab. This paper reports the cryogenic test results of the HOM couplers with the SPS prototype rf-dipole cavity.
	Slides TUOP05 [0.859 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO033
About •	paper received ※ 17 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019
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TUOP06	Vertical Test Results of Plasma In-situ Cleaning on Low Beta HWR Cavity
TUPO036	use link to access more material from this paper's primary paper code
	A.D. Wu, H. Guo, Y. He, C.F. Hu, S.C. Huang, C.L. Li, Y.M. Li, X. Liu, F. Pan, Y.K. Song, P.R. Xiong, L. Yang, W.M. Yue, C. Zhang, S.H. Zhang, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	Field emission occurred in SRF cavity is the major limitation to operate at high gradient with stability. The plasma in-situ cleaning for the low beta HWR cavity was carried out to remove the hydrocarbons contaminants on the inner cavity surface. And the vertical test results indicated that the field emission effect was relieved with the increasing of the quench point and emission set-on point. Thus, oxygen active plasma processing can be an effective method to solve the field emission issues for the low beta HWR cavity.
	Slides TUOP06 [1.281 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO036
About •	paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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TUOP07	Tests of the Balloon Single Spoke Resonator
TUPO039	use link to access more material from this paper's primary paper code
	Z.Y. Yao, J.J. Keir, D. Kishi, D. Lang, R.E. Laxdal, H. Liu, Y. Ma, B. Matheson, B.S. Waraich, Q. Zheng, V. Zvyagintsev TRIUMF, Vancouver, Canada
	A balloon variant of the single spoke resonator (SSR) has been designed, fabricated and tested. The cavity is the SSR1 prototype for the Rare Isotope Science Project (RISP) in Korea. It is specifically designed to reduce the likelihood of multipacting barriers near the operating point. A systematic multipacting study leads to a novel geometry, a spherical cavity with re-entrant irises and a spoke. Other than eliminating multipacting around operational gradient, the balloon shape also provides competitive RF parameters and robust mechanical structure. Cryostat cold tests demonstrated cavity performance on each design aspect. The cold tests will be reported in this paper.
	Slides TUOP07 [25.279 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO039
About •	paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUOP08	Development of CW Heavy Ion Linac at IMP
TUPO003	use link to access more material from this paper's primary paper code
	X. Yin, H. Du, Y. He, Q.Y. Kong, X.N. Li, Z.S. Li, L.Z. Ma, J. Meng, C. Qian, L.T. Sun, K.D. Wang, J.X. Wu, J.W. Xia, W.J. Xie, Z. Xu, Y.Q. Yang, Q.G. Yao, Y.J. Yuan, W. Zhang, X.Z. Zhang, Y. Zhang, H.W. Zhao, Z.Z. Zhou IMP/CAS, Lanzhou, People’s Republic of China J.E. Chen, S.L. Gao, G. Liu, Y.R. Lu, Z. Wang, X.Q. Yan, K. Zhu PKU, Beijing, People’s Republic of China
	A new heavy ion linac as the injector for the Separated Sector Cyclotron (SSC), named SSC-Linac[1], is being under constructed at the national laboratory Heavy Ion Research Facility in Lanzhou (HIRFL). The SSC-Linac mainly consists of a 4-rod RFQ and three IH-DTL cavities which can accelerate ion of A⁄q≤7from 3.73 keV/u to 1.025 MeV/u. Both of themoperating at 53.667MHz had been developed. In the commissioning, ions weresuccessfully accelerated to 0.295MeV/u by IH-DTL1. The beam commissioningof the IH-DTL2 which can accelerate the ion to 0.586MeV/u will come soon. In this paper, the recent R&D progress of the SSC-Linac including the development of key components and the beam commissioning results arepresented.
	Slides TUOP08 [7.335 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO003
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUOP09	Extension of Busch’s Theorem to Particle Beams
TUPO078	use link to access more material from this paper's primary paper code
	L. Groening, C. Xiao GSI, Darmstadt, Germany M. Chung UNIST, Ulsan, Republic of Korea
	In 1926, H. Busch formulated a theorem for one single charged particle moving along a region with longitudinal magnetic field. The theorem relates particle angular momentum to the amount of field lines being enclosed by the particle cyclotron motion. Recently it has been extended to accelerated particle beams [Phys. Rev. Accel. Beams 21 014201 (2018)]. This contribution sketches this extension and applies the extended theorem to successfully performed emittance manipulations with electron and ion beams.
	Slides TUOP09 [0.999 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO078
About •	paper received ※ 24 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUOP10	Numerical and Experimental Study of H⁻ Beam Dynamics in J-PARC LEBT
TUPO079	use link to access more material from this paper's primary paper code
	T. Shibata, K. Ikegami, Y. Liu, K. Ohkoshi, M. Otani J-PARC, KEK & JAEA, Ibaraki-ken, Japan A. Miura, H. Oguri, K. Shinto JAEA/J-PARC, Tokai-mura, Japan F. Naito, K. Nanmo, A. Takagi KEK, Tokai, Ibaraki, Japan
	Negative hydrogen ion (H⁻) beam dynamics in J-PARC Low Energy Beam Transport (LEBT) has been investigated by numerical modeling which calculates particle transport with effect of space charge and collision processes. Understandings of H⁻ beam transport in LEBT is important for high transmission rate from Ion Source (IS) to Radio Frequency Quadrupole (RFQ) in J-PARC in higher beam current in future. In 2017, 45 mA beam current of H⁻ has been extracted from IS in J-PARC user operation which has been increased from 30 mA in last 2 years. The beam current is planned to be increased to 50 mA in the next upgrade. As the beam current increase, IS/LEBT commissioning becomes more difficult because of the higher space charge (SC). Especially in J-PARC, vacuum pressure is around 10^-5 Pa by 15 mmf orifice located in the center of LEBT. The orifice prevents residual gas injection from IS to LEBT/RFQ and thus produces stronger SC effect. In the presentation, numerical results are compared with actual results from J-PARC Linac beam commissioning. A comparison of the results shows that location of the 15 mmf orifice results in two peaks of RFQ transmission rate against SOL currents.
	Slides TUOP10 [0.968 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO079
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUOP11	The CW Beam Experiment of Window-type RFQ
TUPO015	use link to access more material from this paper's primary paper code
	K. Zhu PKU, Beijing, People’s Republic of China
	Funding: work supported by NSFC. Grand No. 2014CB845503 A window-type RFQ is designed and fabricated by Peking University. It is planed to accelerate 50mA deuteron cw beam to 1MeV. The 60kV intervane voltage is designed to decrease the risk of high voltage discharge since the RFQ works in cw mode. High power test shows that the intervane voltage is over 60kV when the Cavity power consumption is 48kW. The beam experiment was done and 1.8mA cw beam was obtained at exit of RFQ with over 90% transmission efficiency. This paper will present the cold model measurement, high power RF conditioning and beam experiment result.
	Slides TUOP11 [2.051 MB]
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TUOP12	Determination of the Field-dependence of the Surface Resistance of Superconductors from Cavity Tests
TUPO035	use link to access more material from this paper's primary paper code
	J.R. Delayen, S.U. De Silva, H. Park ODU, Norfolk, Virginia, USA
	Cryogenic tests of superconducting cavities yield an average surface resistance as a function of the peak surface magnetic field. An analytical formalism has been developed to extract the actual field dependence of the surface resistance from cavity tests and is applied to coaxial cavities and cavities of more complex geometries.
	Slides TUOP12 [0.524 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO035
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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Paper

Title

Page

TUOP01

Fundamental Studies of Impurity Doping in 1.3 GHz and Higher Frequency SRF Cavities

SPWR018

use link to access more material from this paper's primary paper code

TUPO054

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J.T. Maniscalco, P.N. Koufalis, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

As the demand for more powerful, more efficient, and smaller superconducting RF accelerators continues to increase, both impurity doping and high-frequency cavities (> 1.3 GHz) have become hot topics for fundamental research because of their potential to significantly decrease surface losses and cost respectively. In this report, we present recent experimental and theoretical results on undoped and nitrogen-doped high-frequency cavities and on alternative doping agents in traditional 1.3 GHz cavities, with a focus on understanding the fundamental science of impurity doping.

Slides TUOP01 [1.956 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO054

About •

paper received ※ 16 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUOP02

FRIB Fast Machine Protection System: Chopper Monitor System Design

TUPO007

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Z. Li, D. Chabot, S. Cogan, S.M. Lidia, R.C. Webber
FRIB, East Lansing, USA

Funding: Work supported by Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The Facility for Rare Isotope Beams tunes the beam power from 0 to 400KW by chopping the beam current with a beam chopper in the Low Energy Beam Transport. A chopper monitoring system is employed to verify proper chopper operation to avoid delivery of undesired high-powered beam and to inhibit beam for machine protection purposes. The system monitors the incoming beam gate time structure, the chopper switch high voltage pulses, the chopper electrode charge/discharge currents, and the status of machine protection system. It is designed to switch off the beam within tens of nanoseconds of a detected fault. Chal-lenges include a dynamic beam gate pulse structure with pulse lengths as short as 0.6 µs and high voltage power supply current pulses of ~25 ns. A high speed "integrate and hold circuit with reset", Field Program-mable Gate Array based digital control circuit and high speed ADC circuit were developed to fulfil the re-quired functions. Design approach, simulation, and test results with the beam are the focus of this paper.

Slides TUOP02 [1.082 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO007

About •

paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUOP03

Precise Evaluation of Characteristic of the Multi-layer Thin-film Superconductor Consisting of NbN and Insulator on Pure Nb Substrate

TUPO030

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R. Katayama, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
C.Z. Antoine
CEA/IRFU, Gif-sur-Yvette, France
A. Four
CEA/DRF/IRFU, Gif-sur-Yvette, France
H. Hayano, T. Kubo, T. Saeki
KEK, Ibaraki, Japan
H. Ito
Sokendai, Ibaraki, Japan
R. Ito, T. Nagata
ULVAC, Inc, Chiba, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

In recent years, it has been pointed out that the maximum accelerating gradient of a superconducting RF cavity can be pushed up by coating the inner surface of the cavity with a multilayer thin-film structure that consists of alternating insulating and superconducting layers. In this structure, the principal parameter that limits the performance of the cavity is the critical magnetic field or effective Hc1 at which vortices start penetrating into the superconductor layer, and it is predicted to depend on the combination of the film thickness. We made samples that have NbN/SiO2 thin-film structure on pure Nb substrate with several thicknesses of NbN film deposited using DC magnetron sputtering method. Here, we report the measurement results of effective Hc1 of the NbN sample with a thickness of 200 nm by using the third-harmonic voltage method. In addition, we report the preliminary results to evaluate the dependence of the effective Hc1 on the thickness of the NbN film in the range 50 nm-200 nm.

Slides TUOP03 [0.305 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO030

About •

paper received ※ 18 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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TUOP04

Investigation of the Surface Resistance of Niobium Between 325 MHz and 1300 MHz Using a Coaxial Half-wave Cavity

TUPO031

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H. Park, S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA

The Center for Accelerator Science at Old Dominion University has built a half-wave coaxial cavity (*) to measure the surface resistance of niobium as a function of frequency, temperature, rf field, preparation techniques, over a wide range of frequencies of interest for particle accelerators. The characteristics of the half-wave coaxial cavity provide these information on a same surface. The preliminary results showed clearly the frequency dependence of residual surface resistance (**). After establishing baseline, we have conducted a study of low temperature baking effect on the surface resistance under controlled environment. This paper will describe the details of the test procedure, results and we will explore underlying physics of the phenomenon.
* H. Park et al., MOPB003, Proc. SRF2015, http://jacow.org/
** H. Park et al., THPB080, Proc. SRF2017, http://jacow.org/

Slides TUOP04 [0.966 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO031

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paper received ※ 17 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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TUOP05

Cryogenic Test Results of the SPS Prototype RF-dipole Crabbing Cavity with Higher Order Mode Couplers

TUPO033

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S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
Z. Li
SLAC, Menlo Park, California, USA
H. Park
JLab, Newport News, Virginia, USA

The rf-dipole crabbing cavity planned for the LHC High Luminosity Upgrade is designed to deliver a transverse kick of 3.34 MV; crabbing the proton beam in the horizontal plane. The proton beams of the LHC machine operating at 7 TeV each sets high impedance thresholds on the crabbing cavity systems. The rf-dipole crabbing cavity is designed with a two higher order mode couplers to suppress those HOMs. The first prototype of the HOM couplers are fabricated at Jefferson Lab. This paper reports the cryogenic test results of the HOM couplers with the SPS prototype rf-dipole cavity.

Slides TUOP05 [0.859 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO033

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paper received ※ 17 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019

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TUOP06

Vertical Test Results of Plasma In-situ Cleaning on Low Beta HWR Cavity

TUPO036

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A.D. Wu, H. Guo, Y. He, C.F. Hu, S.C. Huang, C.L. Li, Y.M. Li, X. Liu, F. Pan, Y.K. Song, P.R. Xiong, L. Yang, W.M. Yue, C. Zhang, S.H. Zhang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

Field emission occurred in SRF cavity is the major limitation to operate at high gradient with stability. The plasma in-situ cleaning for the low beta HWR cavity was carried out to remove the hydrocarbons contaminants on the inner cavity surface. And the vertical test results indicated that the field emission effect was relieved with the increasing of the quench point and emission set-on point. Thus, oxygen active plasma processing can be an effective method to solve the field emission issues for the low beta HWR cavity.

Slides TUOP06 [1.281 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO036

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paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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TUOP07

Tests of the Balloon Single Spoke Resonator

TUPO039

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Z.Y. Yao, J.J. Keir, D. Kishi, D. Lang, R.E. Laxdal, H. Liu, Y. Ma, B. Matheson, B.S. Waraich, Q. Zheng, V. Zvyagintsev
TRIUMF, Vancouver, Canada

A balloon variant of the single spoke resonator (SSR) has been designed, fabricated and tested. The cavity is the SSR1 prototype for the Rare Isotope Science Project (RISP) in Korea. It is specifically designed to reduce the likelihood of multipacting barriers near the operating point. A systematic multipacting study leads to a novel geometry, a spherical cavity with re-entrant irises and a spoke. Other than eliminating multipacting around operational gradient, the balloon shape also provides competitive RF parameters and robust mechanical structure. Cryostat cold tests demonstrated cavity performance on each design aspect. The cold tests will be reported in this paper.

Slides TUOP07 [25.279 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO039

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paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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TUOP08

Development of CW Heavy Ion Linac at IMP

TUPO003

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X. Yin, H. Du, Y. He, Q.Y. Kong, X.N. Li, Z.S. Li, L.Z. Ma, J. Meng, C. Qian, L.T. Sun, K.D. Wang, J.X. Wu, J.W. Xia, W.J. Xie, Z. Xu, Y.Q. Yang, Q.G. Yao, Y.J. Yuan, W. Zhang, X.Z. Zhang, Y. Zhang, H.W. Zhao, Z.Z. Zhou
IMP/CAS, Lanzhou, People’s Republic of China
J.E. Chen, S.L. Gao, G. Liu, Y.R. Lu, Z. Wang, X.Q. Yan, K. Zhu
PKU, Beijing, People’s Republic of China

A new heavy ion linac as the injector for the Separated Sector Cyclotron (SSC), named SSC-Linac[1], is being under constructed at the national laboratory Heavy Ion Research Facility in Lanzhou (HIRFL). The SSC-Linac mainly consists of a 4-rod RFQ and three IH-DTL cavities which can accelerate ion of A⁄q≤7from 3.73 keV/u to 1.025 MeV/u. Both of themoperating at 53.667MHz had been developed. In the commissioning, ions weresuccessfully accelerated to 0.295MeV/u by IH-DTL1. The beam commissioningof the IH-DTL2 which can accelerate the ion to 0.586MeV/u will come soon. In this paper, the recent R&D progress of the SSC-Linac including the development of key components and the beam commissioning results arepresented.

Slides TUOP08 [7.335 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO003

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TUOP09

Extension of Busch’s Theorem to Particle Beams

TUPO078

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L. Groening, C. Xiao
GSI, Darmstadt, Germany
M. Chung
UNIST, Ulsan, Republic of Korea

In 1926, H. Busch formulated a theorem for one single charged particle moving along a region with longitudinal magnetic field. The theorem relates particle angular momentum to the amount of field lines being enclosed by the particle cyclotron motion. Recently it has been extended to accelerated particle beams [Phys. Rev. Accel. Beams 21 014201 (2018)]. This contribution sketches this extension and applies the extended theorem to successfully performed emittance manipulations with electron and ion beams.

Slides TUOP09 [0.999 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO078

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paper received ※ 24 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUOP10

Numerical and Experimental Study of H⁻ Beam Dynamics in J-PARC LEBT

TUPO079

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T. Shibata, K. Ikegami, Y. Liu, K. Ohkoshi, M. Otani
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
A. Miura, H. Oguri, K. Shinto
JAEA/J-PARC, Tokai-mura, Japan
F. Naito, K. Nanmo, A. Takagi
KEK, Tokai, Ibaraki, Japan

Negative hydrogen ion (H⁻) beam dynamics in J-PARC Low Energy Beam Transport (LEBT) has been investigated by numerical modeling which calculates particle transport with effect of space charge and collision processes. Understandings of H⁻ beam transport in LEBT is important for high transmission rate from Ion Source (IS) to Radio Frequency Quadrupole (RFQ) in J-PARC in higher beam current in future. In 2017, 45 mA beam current of H⁻ has been extracted from IS in J-PARC user operation which has been increased from 30 mA in last 2 years. The beam current is planned to be increased to 50 mA in the next upgrade. As the beam current increase, IS/LEBT commissioning becomes more difficult because of the higher space charge (SC). Especially in J-PARC, vacuum pressure is around 10^-5 Pa by 15 mmf orifice located in the center of LEBT. The orifice prevents residual gas injection from IS to LEBT/RFQ and thus produces stronger SC effect. In the presentation, numerical results are compared with actual results from J-PARC Linac beam commissioning. A comparison of the results shows that location of the 15 mmf orifice results in two peaks of RFQ transmission rate against SOL currents.

Slides TUOP10 [0.968 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO079

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TUOP11

The CW Beam Experiment of Window-type RFQ

TUPO015

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K. Zhu
PKU, Beijing, People’s Republic of China

Funding: work supported by NSFC. Grand No. 2014CB845503
A window-type RFQ is designed and fabricated by Peking University. It is planed to accelerate 50mA deuteron cw beam to 1MeV. The 60kV intervane voltage is designed to decrease the risk of high voltage discharge since the RFQ works in cw mode. High power test shows that the intervane voltage is over 60kV when the Cavity power consumption is 48kW. The beam experiment was done and 1.8mA cw beam was obtained at exit of RFQ with over 90% transmission efficiency. This paper will present the cold model measurement, high power RF conditioning and beam experiment result.

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TUOP12

Determination of the Field-dependence of the Surface Resistance of Superconductors from Cavity Tests

TUPO035

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J.R. Delayen, S.U. De Silva, H. Park
ODU, Norfolk, Virginia, USA

Cryogenic tests of superconducting cavities yield an average surface resistance as a function of the peak surface magnetic field. An analytical formalism has been developed to extract the actual field dependence of the surface resistance from cavity tests and is applied to coaxial cavities and cavities of more complex geometries.

Slides TUOP12 [0.524 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO035

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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