IPAC2019 - List of Keywords (DTL)

Paper	Title	Other Keywords	Page
MOZPLM1	Operation Status and Upgrade of CSNS	linac, MMI, cavity, rfq	23
	S. Fu, S. Wang IHEP, Beijing, People’s Republic of China
	China Spallation Neutron Source (CSNS) accelerator complex consists of a front end, an 80MeV DTL linac, and a 1.6GeV Rapid Cycling Synchrotron (RCS).It is designed with a beam power of 100kW in the first phase and reserves upgrade capability to 500kW in the second phase. It has completed initial beam commissioning and has started user operation in 2018. And meanwhile the beam power is quickly going up from the initially above 10kW to 50kW during the user operation, and we can foresee that the designed beam power of 100 kW can be reached in the next year. This talk gives the most recent status of beam power ramping in CSNS, as well as future upgrade plan to increase the beam power up to 500 kW.
	Slides MOZPLM1 [12.157 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZPLM1
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW063	Beam Dynamics Optimization in Drift Tube Linear Accelerator With Permanent Quadrupole Magnets	lattice, rfq, quadrupole, cavity	234
	I. Skudnova Saint Petersburg State University, Saint Petersburg, Russia
	The research concerns the design of a drift tube linear accelerator (DTL) with permanent quadrupole magnets (PMQ) placed inside some of the drift tubes for focusing. The study was conducted using Comsol Multiphysics software, where electromagnetic fields and particle dy-namics in the cavity were calculated. The proton beam is accelerated up to 10 MeV. Initial beam is assumed to come from Radio Frequency Quadrupole accelerator (RFQ). Mathematical methods of control theory are used for particles dynamics optimization. Different focusing lattices are examined and variations of the gradient of the magnetic lenses are analyzed with respect to output beam parameters. Effectiveness of the optimization is estimated by the transmission rate and the emittance growth.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW063
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB017	Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/EDM Experiment	cavity, linac, coupling, experiment	606
	Y. Nakazawa, H. Iinuma Ibaraki University, Ibaraki, Japan K. Hasegawa, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan N. Hayashizaki RLNR, Tokyo, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Iwata NIRS, Chiba-shi, Japan N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida KEK, Ibaraki, Japan R. Kitamura, H.Y. Yasuda University of Tokyo, Tokyo, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP18H03707, JP16H03987, and JP16J07784. An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the RF field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, a test coupler is designed and fabricated. In this paper, the development of the coupler and the result of the low-power measurement will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB017
About •	paper received ※ 29 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPTS015	FoS Cavity of the Alvarez 2.0 DTL as FAIR Injector	cavity, quadrupole, operation, linac	871
	M. Heilmann, X. Du, L. Groening, S. Mickat, C. Mühle, A. Rubin, V. Srinivasan GSI, Darmstadt, Germany
	The Alvarez 2.0 DTL will be the new post-stripper DTL of the UNILAC at GSI. The existing GSI with its LINAC and SIS18 comprise the main operation injector chain for the Facility for Antiproton and Ion Research FAIR. The new Alvarez-DTL has an operation frequency of 10⁸.4 MHz, an input energy of 1.358 MeV/u and the output energy is 11.4 MeV/u with a total length of 55 m. The presented FoS section will be part of the first cavity of the Alvarez 2.0 DTL. The FoS-cavity with 11 drift tubes (including quadrupole singlets) and a total length of 1.9 m will be copper plated in GSI for high power tests. The design of the quadrupole singlet magnet is finalized; a prototype of a fully functional magnet with drift tube and stems will be fabricated within a design study. Empty drift tubes and all components of the tank shall be delivered 2019 for first low level RF investigations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS015
About •	paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPTS016	Compression and Noise Reduction of Field Maps	cavity, simulation, MMI, extraction	875
	X. Du, L. Groening GSI, Darmstadt, Germany
	Errors from discretization and large data volume of field maps is a concern for beam dynamics simulations with respect to achievable accuracy and to the required amount of time. High-order singular value decomposition (HOSVD) has recently emerged as simple, effective, and adaptive tool to extract the essentials from multidimensional data. This paper is on the feasibility of compression and noise reduction of electromagnetic field map data with HOSVD. The method has been applied to an electric field map of a DTL cavity with 11 m in length comprising 55 rf-gaps. The original field map data of 220 MB was converted into practically noise-free data of just 20 KB. Noise was reduced by 95% as demonstrated using a cubic cavity for which the analytical field map is available.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS016
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS048	Longitudinal Measurements and Beam Tuning in the J-PARC Linac MEBT1	MEBT, linac, simulation, rfq	968
	M. Otani J-PARC, KEK & JAEA, Ibaraki-ken, Japan K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan K. Hirano, Y. Kondo, A. Miura, H. Oguri JAEA/J-PARC, Tokai-mura, Japan Y. Liu KEK/JAEA, Ibaraki-Ken, Japan
	J-PARC linac is operated with design peak current of 50 mA from October 2018. Recently we succeeded in establishing longitudinal measurement at MEBT1, with which the beam matching is being studied in MEBT1. In this poster, recent measurements and beam tuning results in MEBT1 will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS048
About •	paper received ※ 30 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS063	Design and Low Power Test of a Prototype HOM LINAC	HOM, cavity, linac, impedance	1001
	L. Lu, T. He, C.C. Xing, L. Yang IMP/CAS, Lanzhou, People’s Republic of China L. Yang University of Chinese Academy of Sciences, Beijing, People’s Republic of China
	A 325MHz HOM (higher order mode) type linac was proposed and studied for proton or heavy ion acceleration in medium energy region. The cavity was finished the fabrication already by using copper and aluminum material. We will report results of low power test of the HOM linac in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS063
About •	paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS077	RCCS Operation and Characteristics in Resonance Frequency Control Mode at KOMAC	controls, resonance, operation, radio-frequency	1025
	K.H. Kim, H.S. Jeong, H.S. Kim, S.G. Kim, H.-J. Kwon, Y.G. Song Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
	Funding: This work has been supported through KOMAC (Korea Multi-purpose Accelerator Complex) operation fund of KAERI by MSIT (Ministry of Science and ICT) A 100-MeV proton accelerator is under operation at Korea Multi-purpose Accelerator Complex (KOMAC). The resonance control cooling system (RCCS) has supplied the cooling water to drift tube linac (DTL). The DTL need to keep the resonant frequency of 350MHz during the operation. RCCS has a critical role in sustaining the acceptable resonant frequency error in DTL by adopting the resonance frequency control mode. Details on the RCCS operation in resonance frequency control mode will be given in this study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS077
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS111	Primary Beam Dynamics Design of a Heavy-Ion IH-DTL With Electromagnetic Quadrupoles	quadrupole, focusing, rfq, cavity	1140
	P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng TUB, Beijing, People’s Republic of China
	A new IH-DTL beam dynamics scheme, IH-EMQ (ElectroMagnetic Quadrupole) is presented to obtain a large longitudinal acceptance. In this scheme, electromagnetic quadrupoles are installed inside the drift tubes of IH-DTL. A large-longitudinal-acceptance heavy-ion IH-DTL design is described in this paper. With the limit current of 25 mA, the 90% normalized longitudinal acceptance reaches 87.8 pi.deg. MeV for the 60 MeV 107Au³⁰⁺, which is 8 times of the input emittance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS111
About •	paper received ※ 09 April 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPTS112	Matrix Approach to Decouple Transverse-Coupled Beams	coupling, quadrupole, emittance, solenoid	1144
	P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng TUB, Beijing, People’s Republic of China Y.H. Pu, J. Qiao, C.P. Wang, X.C. Xie, F. Yang Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People’s Republic of China
	Funding: Work supported by the National Key Research and Development Program of China (grant number 2016YFC0105408). Transverse emittances, especially vertical emittance, are strictly required in the synchrotrons with multi-loop injection. Transverse emittances easily grow up if transverse beam phase spaces are coupled. The growth of the transverse emittance can be restained by decoupling the beam phase spaces. Based on the transfer matrix calculation, it can be theoretically proved that the decoupling can be implemented for general situations. A minimum number of rotated quadrupoles required for decoupling is given. Two quadrupoles can decouple the beam and suppress its emittance growth to 1% in the coupling DTL case.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS112
About •	paper received ※ 28 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS114	Upgrades for Subsystems of the 200 MeV H⁻ Linac at BNL	linac, controls, power-supply, cavity	1152
	D. Raparia, G. Atoian, D.M. Gassner, D. Goldberg, O. Gould, T. Lehn, V. LoDestro, M. Mapes, M. Mapes, I. Marneris, S. Polizzo, J. Ritter, A. Zaltsman, A. Zelenski BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. To increase the average current for isotope production by factor of two, we have undertaken several upgrades for our 50-year-old 200 MeV H⁻ linac. Average current will be double by increasing the beam pulse length. We are testing the DTL tanks reliability by increasing RF pulse length and replacing weak RF joints. We are in the process of replace 50-year old ion pumps and a new PLC based vacuum I&C system for the DTL tanks. We are also upgrading/replacing/adding LLRF, diagnostics, machine protection system, and quadrupole power supply. Paper will present status of these activity and future plan.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS114
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPTS027	Progress of J-PARC LINAC Commissioning	linac, lattice, rfq, operation	1990
	Y. Liu KEK/JAEA, Ibaraki-Ken, Japan Z. Fang, K. Futatsukawa, T. Miyao, M. Otani, T. Shibata KEK, Ibaraki, Japan T. Ito, A. Miura, T. Morishita, K. Moriya, K. Okabe, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS027
About •	paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPTS086	SNS Proton Power Upgrade Status	klystron, power-supply, injection, linac	2124
	M.A. Plum, D.E. Anderson, C.N. Barbier, M.S. Champion, M.S. Connell, J. Galambos, M.M. Harvey, M.P. Howell, S.-H. Kim, J. Moss, B.W. Riemer, R.W. Steffey ORNL, Oak Ridge, Tennessee, USA
	Funding: Work performed at (or work supported by) Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. The Proton Power Upgrade (PPU) project at the Oak Ridge Spallation Neutron Source aims to double the beam power capability of the accelerator, from 1.4 to 2.8 MW. This will be done by a 30% increase in beam energy (from 1.0 to 1.3 GeV), and a 50% increase in beam current (from 25 to 38 mA averaged over a macropulse). The project is now well underway, after receiving approval to start preliminary design in April 2018. In this paper we will discuss recent technical developments in the project, including the warm linac RF system upgrade, a new topology for the high voltage converter modulators, an engineering review of the power capability of the injection dump, and a 2-MW-capability for the existing target station.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS086
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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WEPGW033	Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire	electron, high-voltage, vacuum, operation	2543
	R. Kitamura, N. Hayashi, K. Hirano, Y. Kondo, K. Moriya, H. Oguri JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan K. Futatsukawa, T. Miyao, M. Otani KEK, Ibaraki, Japan S. Kosaka, Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPGW042	Development of the Longitudinal Beam Monitor with High Time Resolution for a Muon LINAC in the J-PARC E34 Experiment	laser, experiment, linac, acceleration	2571
	M. Yotsuzuka, K. Inami Nagoya University, Nagoya, Japan K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki KEK, Ibaraki, Japan K. Hasegawa, R. Kitamura, T. Morishita JAEA/J-PARC, Tokai-mura, Japan T. Iijima, Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan T. Iijima KMI, Nagoya, AIchi Prefecture, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan Y. Kondo JAEA, Ibaraki-ken, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226. The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW042
About •	paper received ※ 30 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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WEPRB039	Tuning of a Tapered Ridge-Loaded Waveguide Coupler for a Drift Tube LINAC of the Compact Pulsed Hadron Source	GUI, coupling, linac, target	2893
	Y. Lei, C.T. Du, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People’s Republic of China
	This paper presents the tuning result of a tapered ridge-loaded waveguide coupler for the drift tube linac (DTL) of the compact pulsed hadron source (CPHS) at Tsinghua University. The coupler has been designed, manufactured, and mounted on the DTL cavity for the cold measurement and tuning. The iris diameter of the coupler which is related to the coupling coefficient needs to be determined in the tuning experiment, due to the difference between the designed and measured quality factors. Meanwhile, we found that the relationship between the coupling coefficient and iris diameter from the traditional analytical design method is not applicable when the iris diameter is relatively large. In this paper, the target coupling coeffi-cient is analysed, and the limit of the original analytical design is presented. The measurement method is intro-duced to improve the measurement efficiency and the tuning process of the coupling coefficient to the target value is described. After several iterations, the coupling coefficient is tuned to 1.54 which is close to the desired value of 1.56.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB039
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPRB050	Multipacting Studies of the Coaxial Coupler for BNCT DTL	multipactoring, simulation, impedance, neutron	2921
	M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, A.X. Wang, Y. Wang, X.L. Xiaolei IHEP CSNS, Guangdong Province, People’s Republic of China Q. Chen, S. Fu, H.C. Liu IHEP, Beijing, People’s Republic of China X.L. Wu DNSC, Dongguan, People’s Republic of China
	Funding: Youth Innovation Promotion Association of CAS (2015011) Program for GuangDong Introducting Innovative and Enterpreneurial Teams (2017ZT07S225) Multipacting is a phenomenon in which electrons grow sharply under certain conditions in a RF structure. It may lead to the breakdown or even damage to the equipment. Therefore, it is very important to calculate the Multipact-ing range in the RF equipment design. Since the phe-nomenon is too complicated to use the formula to fully predict it, numerical simulation is employed. There are many computer codes (such as Track3P, MultiPac, CST PS, etc.) used to simulate the phenomenon, but most of them are not commercial. In this paper, theories used in coaxial line for predicting multipacting are introduced; the CST PS is chosen to simulate the multipacting of coaxial coupler for BNCT DTL; finally, methods of sup-pressing multipacting are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB050
About •	paper received ※ 11 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPRB075	Optimizing Room Temperature RF Structures for Accelerator Driven System Operations	vacuum, cavity, operation, RF-structure	2993
	D.L. Brown, M.T. Crofford ORNL, Oak Ridge, Tennessee, USA C.C. Peters ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. Minimizing beam trip rates is one of the key operational goals at the Spallation Neutron Source (SNS). Trip rates are closely monitored, and real-time statistics are kept during beam operations for immediate analysis. Beam trips are automatically binned by the length of the trip along with the cause for each trip. The shortest beam trips occur with the highest frequency and those trip rates are dominated by the room temperature RF structures. There can be many causes for the RF structure malfunctions, but one area that has had a major impact on trip rates is improvement in how RF processing is done on structures after extended maintenance periods. Details about the improvement in RF conditioning will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB075
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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WEPTS023	Hamiltonian Formalism of Intense Beams in Drift-Tube Linear Accelerators	quadrupole, space-charge, acceleration, focusing	3145
	H. Okamoto HU/AdSM, Higashi-Hiroshima, Japan
	Starting from the principle of least action, we construct a general Hamiltonian formalism for beam dynamics in drift-tube linear accelerators (DTLs). The Alvarez-type structure is considered here as an example, but the present theory can readily be extended to other types of conventional linacs. The three-dimensional Hamiltonian derived includes the third-order chromatic term as well as the effects from acceleration and space charge. A clear dynamical analogy between the DTL system and compact Paul ion-trap system is pointed out, which indicates that we can conduct a fundamental design study of high-intensity hadron linacs experimentally in a local tabletop environment instead of relying on large-scale machines.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS023
About •	paper received ※ 09 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPTS031	The Beam Dynamics Design of the Proton Synchrotron Linear Injector for Proton Therapy	rfq, proton, linac, cavity	3167
	J. Qiao, Y.H. Pu, X.C. Xie SINAP, Shanghai, People’s Republic of China
	A compact room-temperature injector is designed to accelerate 20 mA proton beam from 30 keV to 7.0 MeV for the purpose of Proton Synchrotron Linear Injector for Proton Therapy. The main feature of this linac injector is that the 4-vane Radio Frequency Quadrupole (RFQ) and the Drift Tube Linac (DTL) section are matched by one triplet and powered by one RF power source. The beam is matched from the first RFQ section to the second DTL section in traverse and longitudinal directions. The overall accelerating gradient of this design has reached up to 1.6 MV/m with transmission efficiency of 96%.This injector combines a 3 m long 4-vane RFQ from 30 keV to 3.0 MeV with a 0.8 m long H-type DTL section to 7.0 MeV. In general, the design meets the requirements of the Pro-ton Synchrotron and the Terminal treatment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS031
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPMP014	2D TRACKING CODE FOR DRIFT TUBE LINAC	linac, simulation, focusing, drift-tube-linac	3482
	A. Yamaguchi, K. Nakayama, K. Okaya, K. Sato Toshiba, Yokohama, Japan N. Hayashizaki RLNR, Tokyo, Japan Y. Iwata, S. Yamada NIRS, Chiba-shi, Japan T. Takeuchi Toshiba Energy Systems & Solutions Corporation, Keihin Product Operations, Yokohama, Japan
	A 2D tracking code has been developed for Alternating-Phase-Focusing drift tube linacs (APF-DTL). This code can design DTLs with a 2D electric field simulation and particle tracking by approximate equations. In this paper, we describe an outline of the 2D tracking code and a comparison of 2D tracking results and 3D simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP014
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPTS022	The Realization of Iterative Learning Control for J-PARC LINAC LLRF Control System	controls, linac, experiment, LLRF	4155
	S. Li J-PARC, KEK & JAEA, Ibaraki-ken, Japan Z. Fang, Y. Fukui, K. Futatsukawa, F. Qiu KEK, Ibaraki, Japan Y. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan
	The beam current of j-parc linac was planned to increase to 60 mA. The stronger beam current will lead to higher beam loading effect. Due to the low Q factor of cavity in high β section of linac, the traditional PID feedback & feedforward control method may have to face huge challenges. In order to make the system run better at 60 mA, the iterative learning control (ILC) method was put forward to use in LLRF control system. All the ILC operations are done in EPICS-PC. By installing the PyEpics module, we can use python programs to realize the data interaction between EPICS system and PC and further realize the ILC algorithm. In this paper, the architecture of ILC methods will be introduced. The performance of ILC method will be reported.
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About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPTS103	First Results of the Analytical Method Used to Reduce Downtime Risk at an Accelerator Facility	target, linac, operation, vacuum	4349
	W.C. Barkley, M.J. Borden, R.W. Garnett, M.S. Gulley, E.L. Kerstiens, M. Pieck, D. Rees, F.E. Shelley, B.G. Smith LANL, Los Alamos, New Mexico, USA
	Funding: DOE The Los Alamos Neutron Science Center (LANSCE), like many other accelerator facilities, was built decades ago and has been repurposed when new missions were adopted. With an ongoing beam availability expectation of at least 80% delivered to the Experimental Areas (EAs), a balance between cost of spare equipment and budget has always been a challenge. Beam availability data has been meticulously captured and binned over the years to completely characterize the Structures, Systems and Components (SSCs) and other factors that have caused or contributed to accelerator downtime. Over these years, a critical spares list prioritized the spare equipment purchases that were deemed most critical by the management team. In the span of the years 2013 ’ 2015, significant accelerator upgrades and equipment replacements were performed in a set of activities known as LANSCE-RM. Last year, a new risk-based approach was developed by the management team that included an analytical assessment and a quantitative evaluation of probability and consequence. The resulting risk register (risk-based equipment list) is being used to guide decisions on funding requests and provide justification to mitigate operational risks. A paper by the same authors was published at LINAC 2018 describing this risk-based approach that serves to reformulate the critical spares list. This paper, in the sections that follow, expands on the approach by detailing the specific results of the analyses that led to the first risk register. Additionally, it evaluates the historical beam downtime at LANSCE compared to the current funding allocation choices made to increase the reliability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS103
About •	paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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Paper

Title

Other Keywords

Page

MOZPLM1

Operation Status and Upgrade of CSNS

linac, MMI, cavity, rfq

23

S. Fu, S. Wang
IHEP, Beijing, People’s Republic of China

China Spallation Neutron Source (CSNS) accelerator complex consists of a front end, an 80MeV DTL linac, and a 1.6GeV Rapid Cycling Synchrotron (RCS).It is designed with a beam power of 100kW in the first phase and reserves upgrade capability to 500kW in the second phase. It has completed initial beam commissioning and has started user operation in 2018. And meanwhile the beam power is quickly going up from the initially above 10kW to 50kW during the user operation, and we can foresee that the designed beam power of 100 kW can be reached in the next year. This talk gives the most recent status of beam power ramping in CSNS, as well as future upgrade plan to increase the beam power up to 500 kW.

Slides MOZPLM1 [12.157 MB]

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW063

Beam Dynamics Optimization in Drift Tube Linear Accelerator With Permanent Quadrupole Magnets

lattice, rfq, quadrupole, cavity

234

I. Skudnova
Saint Petersburg State University, Saint Petersburg, Russia

The research concerns the design of a drift tube linear accelerator (DTL) with permanent quadrupole magnets (PMQ) placed inside some of the drift tubes for focusing. The study was conducted using Comsol Multiphysics software, where electromagnetic fields and particle dy-namics in the cavity were calculated. The proton beam is accelerated up to 10 MeV. Initial beam is assumed to come from Radio Frequency Quadrupole accelerator (RFQ). Mathematical methods of control theory are used for particles dynamics optimization. Different focusing lattices are examined and variations of the gradient of the magnetic lenses are analyzed with respect to output beam parameters. Effectiveness of the optimization is estimated by the transmission rate and the emittance growth.

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paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB017

Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/EDM Experiment

cavity, linac, coupling, experiment

606

Y. Nakazawa, H. Iinuma
Ibaraki University, Ibaraki, Japan
K. Hasegawa, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida
KEK, Ibaraki, Japan
R. Kitamura, H.Y. Yasuda
University of Tokyo, Tokyo, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP18H03707, JP16H03987, and JP16J07784.
An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the RF field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, a test coupler is designed and fabricated. In this paper, the development of the coupler and the result of the low-power measurement will be presented.

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paper received ※ 29 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPTS015

FoS Cavity of the Alvarez 2.0 DTL as FAIR Injector

cavity, quadrupole, operation, linac

871

M. Heilmann, X. Du, L. Groening, S. Mickat, C. Mühle, A. Rubin, V. Srinivasan
GSI, Darmstadt, Germany

The Alvarez 2.0 DTL will be the new post-stripper DTL of the UNILAC at GSI. The existing GSI with its LINAC and SIS18 comprise the main operation injector chain for the Facility for Antiproton and Ion Research FAIR. The new Alvarez-DTL has an operation frequency of 10⁸.4 MHz, an input energy of 1.358 MeV/u and the output energy is 11.4 MeV/u with a total length of 55 m. The presented FoS section will be part of the first cavity of the Alvarez 2.0 DTL. The FoS-cavity with 11 drift tubes (including quadrupole singlets) and a total length of 1.9 m will be copper plated in GSI for high power tests. The design of the quadrupole singlet magnet is finalized; a prototype of a fully functional magnet with drift tube and stems will be fabricated within a design study. Empty drift tubes and all components of the tank shall be delivered 2019 for first low level RF investigations.

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paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPTS016

Compression and Noise Reduction of Field Maps

cavity, simulation, MMI, extraction

875

X. Du, L. Groening
GSI, Darmstadt, Germany

Errors from discretization and large data volume of field maps is a concern for beam dynamics simulations with respect to achievable accuracy and to the required amount of time. High-order singular value decomposition (HOSVD) has recently emerged as simple, effective, and adaptive tool to extract the essentials from multidimensional data. This paper is on the feasibility of compression and noise reduction of electromagnetic field map data with HOSVD. The method has been applied to an electric field map of a DTL cavity with 11 m in length comprising 55 rf-gaps. The original field map data of 220 MB was converted into practically noise-free data of just 20 KB. Noise was reduced by 95% as demonstrated using a cubic cavity for which the analytical field map is available.

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPTS048

Longitudinal Measurements and Beam Tuning in the J-PARC Linac MEBT1

MEBT, linac, simulation, rfq

968

M. Otani
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
K. Hirano, Y. Kondo, A. Miura, H. Oguri
JAEA/J-PARC, Tokai-mura, Japan
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan

J-PARC linac is operated with design peak current of 50 mA from October 2018. Recently we succeeded in establishing longitudinal measurement at MEBT1, with which the beam matching is being studied in MEBT1. In this poster, recent measurements and beam tuning results in MEBT1 will be presented.

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paper received ※ 30 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS063

Design and Low Power Test of a Prototype HOM LINAC

HOM, cavity, linac, impedance

1001

L. Lu, T. He, C.C. Xing, L. Yang
IMP/CAS, Lanzhou, People’s Republic of China
L. Yang
University of Chinese Academy of Sciences, Beijing, People’s Republic of China

A 325MHz HOM (higher order mode) type linac was proposed and studied for proton or heavy ion acceleration in medium energy region. The cavity was finished the fabrication already by using copper and aluminum material. We will report results of low power test of the HOM linac in this paper.

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paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPTS077

RCCS Operation and Characteristics in Resonance Frequency Control Mode at KOMAC

controls, resonance, operation, radio-frequency

1025

K.H. Kim, H.S. Jeong, H.S. Kim, S.G. Kim, H.-J. Kwon, Y.G. Song
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea

Funding: This work has been supported through KOMAC (Korea Multi-purpose Accelerator Complex) operation fund of KAERI by MSIT (Ministry of Science and ICT)
A 100-MeV proton accelerator is under operation at Korea Multi-purpose Accelerator Complex (KOMAC). The resonance control cooling system (RCCS) has supplied the cooling water to drift tube linac (DTL). The DTL need to keep the resonant frequency of 350MHz during the operation. RCCS has a critical role in sustaining the acceptable resonant frequency error in DTL by adopting the resonance frequency control mode. Details on the RCCS operation in resonance frequency control mode will be given in this study.

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MOPTS111

Primary Beam Dynamics Design of a Heavy-Ion IH-DTL With Electromagnetic Quadrupoles

quadrupole, focusing, rfq, cavity

1140

P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China

A new IH-DTL beam dynamics scheme, IH-EMQ (ElectroMagnetic Quadrupole) is presented to obtain a large longitudinal acceptance. In this scheme, electromagnetic quadrupoles are installed inside the drift tubes of IH-DTL. A large-longitudinal-acceptance heavy-ion IH-DTL design is described in this paper. With the limit current of 25 mA, the 90% normalized longitudinal acceptance reaches 87.8 pi.deg. MeV for the 60 MeV 107Au³⁰⁺, which is 8 times of the input emittance.

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paper received ※ 09 April 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPTS112

Matrix Approach to Decouple Transverse-Coupled Beams

coupling, quadrupole, emittance, solenoid

1144

P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China
Y.H. Pu, J. Qiao, C.P. Wang, X.C. Xie, F. Yang
Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People’s Republic of China

Funding: Work supported by the National Key Research and Development Program of China (grant number 2016YFC0105408).
Transverse emittances, especially vertical emittance, are strictly required in the synchrotrons with multi-loop injection. Transverse emittances easily grow up if transverse beam phase spaces are coupled. The growth of the transverse emittance can be restained by decoupling the beam phase spaces. Based on the transfer matrix calculation, it can be theoretically proved that the decoupling can be implemented for general situations. A minimum number of rotated quadrupoles required for decoupling is given. Two quadrupoles can decouple the beam and suppress its emittance growth to 1% in the coupling DTL case.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS112

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paper received ※ 28 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS114

Upgrades for Subsystems of the 200 MeV H⁻ Linac at BNL

linac, controls, power-supply, cavity

1152

D. Raparia, G. Atoian, D.M. Gassner, D. Goldberg, O. Gould, T. Lehn, V. LoDestro, M. Mapes, M. Mapes, I. Marneris, S. Polizzo, J. Ritter, A. Zaltsman, A. Zelenski
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
To increase the average current for isotope production by factor of two, we have undertaken several upgrades for our 50-year-old 200 MeV H⁻ linac. Average current will be double by increasing the beam pulse length. We are testing the DTL tanks reliability by increasing RF pulse length and replacing weak RF joints. We are in the process of replace 50-year old ion pumps and a new PLC based vacuum I&C system for the DTL tanks. We are also upgrading/replacing/adding LLRF, diagnostics, machine protection system, and quadrupole power supply. Paper will present status of these activity and future plan.

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS027

Progress of J-PARC LINAC Commissioning

linac, lattice, rfq, operation

1990

Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
Z. Fang, K. Futatsukawa, T. Miyao, M. Otani, T. Shibata
KEK, Ibaraki, Japan
T. Ito, A. Miura, T. Morishita, K. Moriya, K. Okabe, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.

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TUPTS086

SNS Proton Power Upgrade Status

klystron, power-supply, injection, linac

2124

M.A. Plum, D.E. Anderson, C.N. Barbier, M.S. Champion, M.S. Connell, J. Galambos, M.M. Harvey, M.P. Howell, S.-H. Kim, J. Moss, B.W. Riemer, R.W. Steffey
ORNL, Oak Ridge, Tennessee, USA

Funding: Work performed at (or work supported by) Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
The Proton Power Upgrade (PPU) project at the Oak Ridge Spallation Neutron Source aims to double the beam power capability of the accelerator, from 1.4 to 2.8 MW. This will be done by a 30% increase in beam energy (from 1.0 to 1.3 GeV), and a 50% increase in beam current (from 25 to 38 mA averaged over a macropulse). The project is now well underway, after receiving approval to start preliminary design in April 2018. In this paper we will discuss recent technical developments in the project, including the warm linac RF system upgrade, a new topology for the high voltage converter modulators, an engineering review of the power capability of the injection dump, and a 2-MW-capability for the existing target station.

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WEPGW033

Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire

electron, high-voltage, vacuum, operation

2543

R. Kitamura, N. Hayashi, K. Hirano, Y. Kondo, K. Moriya, H. Oguri
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao, M. Otani
KEK, Ibaraki, Japan
S. Kosaka, Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW042

Development of the Longitudinal Beam Monitor with High Time Resolution for a Muon LINAC in the J-PARC E34 Experiment

laser, experiment, linac, acceleration

2571

M. Yotsuzuka, K. Inami
Nagoya University, Nagoya, Japan
K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki
KEK, Ibaraki, Japan
K. Hasegawa, R. Kitamura, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
T. Iijima
KMI, Nagoya, AIchi Prefecture, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226.
The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported.

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WEPRB039

Tuning of a Tapered Ridge-Loaded Waveguide Coupler for a Drift Tube LINAC of the Compact Pulsed Hadron Source

GUI, coupling, linac, target

2893

Y. Lei, C.T. Du, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People’s Republic of China

This paper presents the tuning result of a tapered ridge-loaded waveguide coupler for the drift tube linac (DTL) of the compact pulsed hadron source (CPHS) at Tsinghua University. The coupler has been designed, manufactured, and mounted on the DTL cavity for the cold measurement and tuning. The iris diameter of the coupler which is related to the coupling coefficient needs to be determined in the tuning experiment, due to the difference between the designed and measured quality factors. Meanwhile, we found that the relationship between the coupling coefficient and iris diameter from the traditional analytical design method is not applicable when the iris diameter is relatively large. In this paper, the target coupling coeffi-cient is analysed, and the limit of the original analytical design is presented. The measurement method is intro-duced to improve the measurement efficiency and the tuning process of the coupling coefficient to the target value is described. After several iterations, the coupling coefficient is tuned to 1.54 which is close to the desired value of 1.56.

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WEPRB050

Multipacting Studies of the Coaxial Coupler for BNCT DTL

multipactoring, simulation, impedance, neutron

2921

M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, A.X. Wang, Y. Wang, X.L. Xiaolei
IHEP CSNS, Guangdong Province, People’s Republic of China
Q. Chen, S. Fu, H.C. Liu
IHEP, Beijing, People’s Republic of China
X.L. Wu
DNSC, Dongguan, People’s Republic of China

Funding: Youth Innovation Promotion Association of CAS (2015011) Program for GuangDong Introducting Innovative and Enterpreneurial Teams (2017ZT07S225)
Multipacting is a phenomenon in which electrons grow sharply under certain conditions in a RF structure. It may lead to the breakdown or even damage to the equipment. Therefore, it is very important to calculate the Multipact-ing range in the RF equipment design. Since the phe-nomenon is too complicated to use the formula to fully predict it, numerical simulation is employed. There are many computer codes (such as Track3P, MultiPac, CST PS, etc.) used to simulate the phenomenon, but most of them are not commercial. In this paper, theories used in coaxial line for predicting multipacting are introduced; the CST PS is chosen to simulate the multipacting of coaxial coupler for BNCT DTL; finally, methods of sup-pressing multipacting are discussed.

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paper received ※ 11 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPRB075

Optimizing Room Temperature RF Structures for Accelerator Driven System Operations

vacuum, cavity, operation, RF-structure

2993

D.L. Brown, M.T. Crofford
ORNL, Oak Ridge, Tennessee, USA
C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Minimizing beam trip rates is one of the key operational goals at the Spallation Neutron Source (SNS). Trip rates are closely monitored, and real-time statistics are kept during beam operations for immediate analysis. Beam trips are automatically binned by the length of the trip along with the cause for each trip. The shortest beam trips occur with the highest frequency and those trip rates are dominated by the room temperature RF structures. There can be many causes for the RF structure malfunctions, but one area that has had a major impact on trip rates is improvement in how RF processing is done on structures after extended maintenance periods. Details about the improvement in RF conditioning will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB075

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paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPTS023

Hamiltonian Formalism of Intense Beams in Drift-Tube Linear Accelerators

quadrupole, space-charge, acceleration, focusing

3145

H. Okamoto
HU/AdSM, Higashi-Hiroshima, Japan

Starting from the principle of least action, we construct a general Hamiltonian formalism for beam dynamics in drift-tube linear accelerators (DTLs). The Alvarez-type structure is considered here as an example, but the present theory can readily be extended to other types of conventional linacs. The three-dimensional Hamiltonian derived includes the third-order chromatic term as well as the effects from acceleration and space charge. A clear dynamical analogy between the DTL system and compact Paul ion-trap system is pointed out, which indicates that we can conduct a fundamental design study of high-intensity hadron linacs experimentally in a local tabletop environment instead of relying on large-scale machines.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS023

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paper received ※ 09 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPTS031

The Beam Dynamics Design of the Proton Synchrotron Linear Injector for Proton Therapy

rfq, proton, linac, cavity

3167

J. Qiao, Y.H. Pu, X.C. Xie
SINAP, Shanghai, People’s Republic of China

A compact room-temperature injector is designed to accelerate 20 mA proton beam from 30 keV to 7.0 MeV for the purpose of Proton Synchrotron Linear Injector for Proton Therapy. The main feature of this linac injector is that the 4-vane Radio Frequency Quadrupole (RFQ) and the Drift Tube Linac (DTL) section are matched by one triplet and powered by one RF power source. The beam is matched from the first RFQ section to the second DTL section in traverse and longitudinal directions. The overall accelerating gradient of this design has reached up to 1.6 MV/m with transmission efficiency of 96%.This injector combines a 3 m long 4-vane RFQ from 30 keV to 3.0 MeV with a 0.8 m long H-type DTL section to 7.0 MeV. In general, the design meets the requirements of the Pro-ton Synchrotron and the Terminal treatment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS031

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPMP014

2D TRACKING CODE FOR DRIFT TUBE LINAC

linac, simulation, focusing, drift-tube-linac

3482

A. Yamaguchi, K. Nakayama, K. Okaya, K. Sato
Toshiba, Yokohama, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwata, S. Yamada
NIRS, Chiba-shi, Japan
T. Takeuchi
Toshiba Energy Systems & Solutions Corporation, Keihin Product Operations, Yokohama, Japan

A 2D tracking code has been developed for Alternating-Phase-Focusing drift tube linacs (APF-DTL). This code can design DTLs with a 2D electric field simulation and particle tracking by approximate equations. In this paper, we describe an outline of the 2D tracking code and a comparison of 2D tracking results and 3D simulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP014

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS022

The Realization of Iterative Learning Control for J-PARC LINAC LLRF Control System

controls, linac, experiment, LLRF

4155

S. Li
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Z. Fang, Y. Fukui, K. Futatsukawa, F. Qiu
KEK, Ibaraki, Japan
Y. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

The beam current of j-parc linac was planned to increase to 60 mA. The stronger beam current will lead to higher beam loading effect. Due to the low Q factor of cavity in high β section of linac, the traditional PID feedback & feedforward control method may have to face huge challenges. In order to make the system run better at 60 mA, the iterative learning control (ILC) method was put forward to use in LLRF control system. All the ILC operations are done in EPICS-PC. By installing the PyEpics module, we can use python programs to realize the data interaction between EPICS system and PC and further realize the ILC algorithm. In this paper, the architecture of ILC methods will be introduced. The performance of ILC method will be reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS022

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS103

First Results of the Analytical Method Used to Reduce Downtime Risk at an Accelerator Facility

target, linac, operation, vacuum

4349

W.C. Barkley, M.J. Borden, R.W. Garnett, M.S. Gulley, E.L. Kerstiens, M. Pieck, D. Rees, F.E. Shelley, B.G. Smith
LANL, Los Alamos, New Mexico, USA

Funding: DOE
The Los Alamos Neutron Science Center (LANSCE), like many other accelerator facilities, was built decades ago and has been repurposed when new missions were adopted. With an ongoing beam availability expectation of at least 80% delivered to the Experimental Areas (EAs), a balance between cost of spare equipment and budget has always been a challenge. Beam availability data has been meticulously captured and binned over the years to completely characterize the Structures, Systems and Components (SSCs) and other factors that have caused or contributed to accelerator downtime. Over these years, a critical spares list prioritized the spare equipment purchases that were deemed most critical by the management team. In the span of the years 2013 ’ 2015, significant accelerator upgrades and equipment replacements were performed in a set of activities known as LANSCE-RM. Last year, a new risk-based approach was developed by the management team that included an analytical assessment and a quantitative evaluation of probability and consequence. The resulting risk register (risk-based equipment list) is being used to guide decisions on funding requests and provide justification to mitigate operational risks. A paper by the same authors was published at LINAC 2018 describing this risk-based approach that serves to reformulate the critical spares list. This paper, in the sections that follow, expands on the approach by detailing the specific results of the analyses that led to the first risk register. Additionally, it evaluates the historical beam downtime at LANSCE compared to the current funding allocation choices made to increase the reliability.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS103

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paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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