IPAC2012 - List of Keywords (DTL)

Paper	Title	Other Keywords	Page
MOPPD076	Numerical Study of a Collimation System to Mitigate Beam Losses in the ESS Linac	linac, beam-losses, collimation, simulation	541
	R. Miyamoto, H. Danared, M. Eshraqi, A. Ponton ESS, Lund, Sweden
	The European Spallation Source (ESS) will be a 5 MW proton linac to produce spallation neutrons. A high power linac has a very low tolerance on beam losses, typically on the order of 1 W/m, to avoid activation of the linac components; hence, emittance and halo of the beam must be well controlled throughout the linac. A system of collimators in beam transport sections has been studied and tested as a means to mitigate the beam losses in several linacs. This paper presents the result of a numerical study of a collimation system for the ESS linac.

MOPPR039	Development of Beam Position Monitor for PEFP Linac and Beam line	linac, proton, coupling, quadrupole	864
	J.Y. Ryu, Y.-S. Cho, J.-H. Jang, H.S. Kim, H.-J. Kwon, K.T. Seol KAERI, Daejon, Republic of Korea
	Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government. The development of the Beam Position Monitor (BPM) is in progress for the linac and beam lines of the Proton Engineering Frontier Project (PEFP). We choose a strip line BPM for the PEFP 20-MeV and 100-MeV beam lines in order to increase the sensitivity of the relatively long bunches in the beam lines. We also selected the same type BPM for the proton linac in the energy range between 20-MeV and 100-MeV. The prototype BPM was designed, fabricated and tested at KAERI site, where the 20-MeV linac was operated. To check the performance of the BPM, we performed the field mapping. The characteristics and test results of the BPM on the test bench as well as with 20-MeV proton beam will be presented in this paper.

MOPPR045	Beam Diagnostics for ESS	linac, target, diagnostics, instrumentation	882
	A. Jansson, C. Böhme, B. Cheymol, H. Hassanzadegan, T.J. Shea, L. Tchelidze ESS, Lund, Sweden
	The European Spallation Source (ESS), to be built in the south of Sweden, will use a 2.5 GeV superconducting linac to produce the worlds most powerful neutron source. The project is currently in a pre-construction phase, during which the linac design is being updated. This paper describes the current plans for beam diagnostics in terms of requirements, number and locations of different systems, and possible technical solutions.

TUOBA02	Beam Commissioning and Operation of New Linac Injector for RIKEN RI-beam Factory	cyclotron, ion, linac, ECRIS	1071
	K. Yamada, S. Arai, M. Fujimaki, T. Fujinawa, H. Fujisawa, N. Fukunishi, Y. Higurashi, E. Ikezawa, H. Imao, O. Kamigaito, M. Kase, M. Komiyama, K. Kumagai, T. Maie, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, Y. Watanabe, H. Yamasawa RIKEN Nishina Center, Wako, Japan A. Goto NIRS, Chiba-shi, Japan Y. Sato J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	A new linac injector called RILAC2* has successfully commissioned at the RIKEN RI beam factory (RIBF). The RILAC2 can accelerate very heavy ions with m/q of 7, such as 124Xe¹⁹⁺ and 238U³⁵⁺ from a 28 GHz superconducting ECR ion source*, up to an energy of 680 keV/nucleon in the cw mode. Ions are directory injected into the RIKEN Ring Cyclotron without charge stripping in order to increase the beam intensity, as well as performing independent RIBF experiments and super-heavy-element synthesis. The key features of RILAC2 are the powerful ECRIS, higher extraction voltage of the ECRIS compared to the voltage of the existing injector linac to reduce the space charge effect, improvement of the rf voltage and phase stability, improvement of the vacuum level to reduce the loss by charge exchange, and the compact equipments yet to be installed in the existing AVF cyclotron vault. The first beam acceleration was achieved on December 21, 2010. After the several beam acceleration tests in 2011, we started to operate the RILAC2 to supply beams for the RIBF experiments. O. Kamigaito et al., Proc. of PASJ3-LAM31, WP78, p. 502 (2006); K. Yamada et al., Proc. of IPAC'10, MOPD046, p.789 (2010). ** T. Nakagawa et al., Rev. Sci. Instrum. 79, 02A327 (2008).
	Slides TUOBA02 [9.947 MB]

TUOBA03	H⁻ and Proton Beam Loss Comparison at SNS Superconducting Linac	proton, linac, quadrupole, ion	1074
	A.P. Shishlo, A.V. Aleksandrov, J. Galambos, M.A. Plum ORNL, Oak Ridge, Tennessee, USA E. Laface ESS, Lund, Sweden V.A. Lebedev Fermilab, Batavia, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. A comparison of beam loss in the superconducting part (SCL) of the Spallation Neutron Source (SNS) linac for H⁻ and protons is presented. During the experiment the nominal beam of negative hydrogen ions in the SCL was replaced by a proton beam created by insertion of a thin stripping carbon foil placed in the low energy section of the linac. The observed significant reduction in the beam loss for protons is explained by a domination of the intra-beam stripping mechanism of the beam loss for H-. The details of the experiment are discussed, and a preliminary estimation of the cross section of the reaction H⁻ + H⁻ -> H⁻ + H⁰ + e is presented.
	Slides TUOBA03 [0.772 MB]

WEXA03	Accelerator Physics and Technology for ESS	linac, klystron, target, cryomodule	2073
	H. Danared ESS, Lund, Sweden
	A conceptual design of the 2.5 GeV proton linac of the European Spallation Source, ESS, was presented in a Conceptual Design Report in early 2012. Work is now progressing towards a Technical Design Report at the end of 2012. Changes to the linac configuration during the last year include a somewhat longer DTL and a change to fully segmented cryomodules. This paper reviews the current design status of the accelerator and its subsystems.
	Slides WEXA03 [15.485 MB]

THPPC010	Beam Start-up of J-PARC Linac after the Tohoku Earthquake	linac, quadrupole, acceleration, radiation	3293
	M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan T. Maruta, A. Miura, H. Sako, J. Tamura, G.H. Wei JAEA/J-PARC, Tokai-mura, Japan
	The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant recovering effort including the realignment of most linac components, we have resumed the beam operation of J-PARC linac in December 2011. In this paper, we present the experience in the beam start-up tuning after the earthquake and the status of the linac operation thereafter.

THPPC050	Effects of Grids in Drift Tubes	beam-transport, impedance, proton, linac	3401
	M. Okamura BNL, Upton, Long Island, New York, USA H. Yamauchi Time Corporation, Hiroshima, Japan
	In 2011, we upgraded a 200 MHz buncher in the proton injector for the AGS – RHIC complex. In the buncher we installed four grids made of tungsten to improve a transit time factor of the buncher. The grid installed drift tubes have 32 mm of inner diameter and the each grid consists of four quadrants. The quadrants were cut out precisely from 1mm thick tungsten plates by a CNC wire cutting EDM. In the conference the 3D electric field design and performance of the grid will be discussed. Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.

THPPC069	Design, Test and Implementation of New 201.25 MHz Power Amplifier for the LANSCE Linac	cathode, electron, HOM, cavity	3446
	J.T.M. Lyles, Z. Chen, J. Davis, A.C. Naranjo, D. Rees, G. M. Sandoval, Jr. LANL, Los Alamos, New Mexico, USA D. Baca, R.E. Bratton, R.D. Summers Compa Industries, Inc., Los Alamos, New Mexico, USA N.W. Brennan Texas A&M University, College Station, Texas, USA
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396 A new 201.25 MHz final power amplifier (FPA) has been designed, fabricated, and tested at Los Alamos Neutron Science Center (LANSCE). The prototype FPA has produced 3 MW peak and 250 kW of mean power with 15 dB of power gain and over 60% efficiency. It has been tested for several thousand hours with a load. A Thales TH628 Diacrode® electron tube is key to the performance of the new amplifier. It is configured with a full wavelength output circuit, having the lower main tuner situated ¾λ from the central electron beam region in the tube and the upper slave tuner ¼λ from the same point. The FPA is designed with input and output transmission line cavity circuits, grid decoupling circuits, an adjustable output coupler, DC blocking and RF bypassing capacitors, HOM suppressors, and a cooling system. A pair of production amplifiers are planned to be power-combined for up to 3.6 MW peak power at high duty factor. Three of these combined amplifiers will be installed in place of the original 1968-vintage amplifiers to return LANSCE operation to 12% beam duty factor with higher peak current than presently possible.

THPPC070	A High Power Test Facility for New 201.25 MHz Power Amplifiers and Components	power-supply, controls, status, linac	3449
	J.T.M. Lyles, J. Davis, D. Rees, G. M. Sandoval, Jr., A. Steck, D.J. Vigil LANL, Los Alamos, New Mexico, USA D. Baca, R.E. Bratton, R.D. Summers Compa Industries, Inc., Los Alamos, New Mexico, USA N.W. Brennan Texas A&M University, College Station, Texas, USA
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396 A new test facility was designed and constructed at Los Alamos Neutron Science Center (LANSCE) for testing a new Thales TH628 Diacrode® final power amplifier and associated driver stages. Anode power requirements for the TH628 are 28 kV DC, with 190 Amperes in millisecond pulses. A 225 uF capacitor bank supplies this current demand, with a crowbar circuit to rapidly discharge 88 kJ of stored energy. Charging current was obtained by re-configuring a 2 MW beam power supply remaining from another project. The power tubes are operated with DC anode voltage, and beam pulsing is done with control grid bias switching at relatively low power. A new Fast Protect and Monitor System was designed to take samples of RF reflected power, anode HV, and various tube currents, with logic outputs to promptly remove high voltages, RF drive and beam pulsing during faults. The entire test system is controlled with a programmable logic controller, for normal startup sequencing, protection against loss of cooling, and operator GUI. This test facility has been used over the past year to test the amplifiers along with high power coaxial components such as hybrid couplers and various water loads.

THPPP034	Optimization of a CW RFQ Prototype	rfq, simulation, impedance, linac	3809
	U. Bartz, J. Gerbig, H.C. Lenz, A. Schempp IAP, Frankfurt am Main, Germany
	A short RFQ prototype was built for RF-tests of high power RFQ structures. We studied thermal effects to determine critical points of the design. HF-simulations with CST Microwave Studio and measurements were done. The cw-tests with 20 kW/m RF-power and simulations of thermal effects with ALGOR were finished successfully. The optimization of some details of the RF design is on focus now. Results and the status of the project will be presented

THPPP036	First Measurements of an Coupled CH Power Cavity for the FAIR Proton Injector	cavity, linac, coupling, proton	3812
	R. M. Brodhage, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany G. Clemente, L. Groening GSI, Darmstadt, Germany
	For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. For this second tank technical and mechanical investigations have been performed to develop a complete technical concept for manufacturing. In Spring 2011, the construction of the first power prototype has started. The main components of this cavity were ready for measurements in fall 2011. At that time, the cavity was tested with a preliminary aluminum drift tube structure, which will allow precise frequency and field tuning. This paper will report on the recent technical developments and achievements. It will outline the main tuning and commissioning steps towards that novel type of proton DTL and it will show very promising results of the latest measurements.

THPPP043	Installation of 100-MeV Proton Linac for PEFP	linac, proton, klystron, site	3832
	Y.-S. Cho, S. Cha, J.S. Hong, J.-H. Jang, D.I. Kim, H.S. Kim, H.-J. Kwon, B.-S. Park, J.Y. Ryu, K.T. Seol, Y.-G. Song, S.P. Yun KAERI, Daejon, Republic of Korea
	Funding: This work was supported by the Ministry of Education, Science and Technology of the Korean Government. The Proton Engineering Frontier Project (PEFP) at Korea Atomic Energy Research Institute (KAERI) is developing a 100-MeV proton linac in order to supply 20-MeV and 100-MeV proton beams to users for proton beam application. The linac consists of a 50-keV injector, a 3-MeV radio frequency quadrupole (RFQ) and a 100-MeV drift tube linac (DTL). The operation of the 20-MeV part of linac at Daejeon site was finished on November 2011. It was disassembled and moved to the Gyeongju site for installation as a low energy part of the linac. We completed the fabrication and test of the accelerating structures. The installation of the proton linac started in December 2011 at the new project site. The user service is scheduled for 2013 through the beam commissioning in 2012. This work summarized the installation status of the proton linac.

THPPP044	RF Set-up Scheme for PEFP DTL	linac, proton, rfq, simulation	3835
	J.-H. Jang, Y.-S. Cho, H.S. Kim, H.-J. Kwon KAERI, Daejon, Republic of Korea
	Funding: This work was supported by the Ministry of Education, Science and Technology of the Korean Government. The proton engineering frontier project (PEFP) is developing a 100-MeV proton linac which consists of a 50 keV injector, a 3-MeV radio frequency quadrupole (RFQ) and a 100-MeV drift tube linac (DTL). The installation of the linac was started in December 2011. The beam commissioning is scheduled for 2012. The phase scan signature method is a common technique to determine the rf set point including the amplitude and phase in DTL tanks. This work summarized the rf set-up scheme for PEFP DTL tanks by using the phase scan signature method.

THPPP046	ESS End-to-End Simulations: a Comparison Between IMPACT and MADX	linac, simulation, space-charge, cavity	3841
	E. Laface, R. Miyamoto ESS, Lund, Sweden D.C. Plostinar, C.R. Prior STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The European Spallation Source will be a 5 MW superconducting proton linac for the production of spallation neutrons. It is composed of an ion source, a radio frequency quadrupole, a drift tube linac and a superconducting linac as well as the low, medium and high, energy beam transport sections. At present these components of the linac are in the design phase: the optimization of the accelerator parameters requires an intensive campaign of simulations to test the model of the machine under possible operational conditions. In this paper the results of simulations performed with the IMPACT and MADX-PTC codes are presented and a comparison is made between them and independent simulations using TraceWin. The dynamics of the beam envelope and single and multi-particle tracking are reported.

THPPP052	Modelling the ISIS 70 MeV Linac	linac, rfq, quadrupole, simulation	3859
	D.C. Plostinar, C.R. Prior, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom A.W. Mitchell University of Warwick, Coventry, United Kingdom
	The ISIS linac consists of four DTL tanks that accelerate a 50 pps, 20 mA H⁻ beam up to 70 MeV before injecting it into an 800 MeV synchrotron. Over the last decades, the linac has proved to be a stable and reliable injector for ISIS, which is a significant achievement considering that two of the tanks are nearly 60 years old. At the time the machine was designed, the limited computing power available and the absence of modern modeling codes, made the creation of a complex simulation model almost impossible. However, over the last few years, computer tools have became an integral part of any accelerator design, so in this paper we present a beam dynamics model of the ISIS linac. A comparison between the simulation results and machine operation data will be discussed, as well as possible linac tuning scenarios and recommended upgrades based on the new model.

THPPP069	Double-Gap Rebuncher Cavity Design of SNS MEBT	cavity, simulation, linac, impedance	3898
	K.R. Shin ORNL RAD, Oak Ridge, Tennessee, USA A.E. Fathy University of Tennessee, Knoxville, Tennessee, USA Y.W. Kang ORNL, Oak Ridge, Tennessee, USA
	A double-gap rebuncher cavity has been studied through design and analysis with computer simulations. This cavity shape is a two cell abridged form of drift tube linac (DTL), instead an omega form of existing single gap elliptical cavity. The cavity operates in TM010 mode, likewise the commonly used single-gap cavities in some medium energy beam transport (MEBT) line of proton accelerators. The new cavity is more power efficient even with slightly lower Q factor because of utilization of two interactive gaps. The breakdown field can be lowered with adjustment of gap and tube length ratio. Electromagnetic, beam envelope, and thermal simulations are presented with comparison to the properties of the conventional elliptical cavity.

THPPP071	Design of the ESS Accelerator	linac, klystron, target, cryomodule	3904
	H. Danared ESS, Lund, Sweden
	The European Spallation Source, ESS, has produced a Conceptual Design Report at the end of 2011 which will evolve towards a Technical Design Report at the end of 2012. This paper is presented on behalf of the ESS Accelerator Design Update Collaboration and will describe the current design of the ESS linear accelerator.

THPPP085	End to End Beam Dynamics of the ESS Linac	linac, proton, target, quadrupole	3933
	M. Eshraqi, H. Danared, A. Ponton ESS, Lund, Sweden I. Bustinduy ESS Bilbao, Bilbao, Spain L. Celona INFN/LNS, Catania, Italy M. Comunian INFN/LNL, Legnaro (PD), Italy A.I.S. Holm, S.P. Møller, H.D. Thomsen ISA, Aarhus, Denmark J. Stovall CERN, Geneva, Switzerland
	The European Spallation Source, ESS, uses a linear accelerator to deliver a high intensity proton beam to the target station. The nominal beam power on target will be 5~MW at an energy of 2.5~GeV. We briefly describe the individual accelerating structures and transport lines through which we have carried out multiparticle beam dynamics simulations. We will present a review of the beam dynamics from the source to the target.

THPPR048	Construction of a BNCT Facility using an 8-MeV High Power Proton Linac in Tokai	neutron, proton, target, radioactivity	4083
	H. Kobayashi, T. Kurihara, H. Matsumoto, M. Yoshioka KEK, Ibaraki, Japan T. Hashirano, F. Inoue, K. Sennyu, T. Sugano MHI, Hiroshima, Japan F. Hiraga, Y. Kiyanagi Hokkaido University, Sapporo, Japan H. Kumada Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan A. Matsumura, H. Sakurai Tsukuba University, Ibaraki, Japan T. Nakamura, H. Nakashima, T. Shibata JAEA, Ibaraki-ken, Japan T. Ohba, Su. Tanaka Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
	An accelerator-based BNCT (Boron Neutron Capture Therapy) facility is now under construction and the entire system including the patient treatment system will be installed in the Ibaraki Medical Center for Advanced Neutron Therapy (tentative name). The linac specification is 8 MeV with 10 mA of average current (80 kW) with a duty factor of 20%. The linac is composed of a 3-MeV RFQ and a drift-tube linac and can accelerate a peak current of 50 mA up to 8-MeV. The neutron producing target is a 0.5 mm thick beryllium disk 150 mm in diameter which is formed on a heat sink plate. The material components used in the neutron moderator system, including the target, should be selected to have a reduced residual radio-activity. Special attention should be paid to mitigate the swelling of target materials due to hydrogen implantation as well. The development of an accelerator-based BNCT suited for practical application requires input from a wide spread of technical specialties. To obtain the needed breath and strength, we have organized our team with contributing members from diverse institutes and companies. The research and development activities of this integrated team will be presented.

Paper

Title

Other Keywords

Page

MOPPD076

Numerical Study of a Collimation System to Mitigate Beam Losses in the ESS Linac

linac, beam-losses, collimation, simulation

541

R. Miyamoto, H. Danared, M. Eshraqi, A. Ponton
ESS, Lund, Sweden

The European Spallation Source (ESS) will be a 5 MW proton linac to produce spallation neutrons. A high power linac has a very low tolerance on beam losses, typically on the order of 1 W/m, to avoid activation of the linac components; hence, emittance and halo of the beam must be well controlled throughout the linac. A system of collimators in beam transport sections has been studied and tested as a means to mitigate the beam losses in several linacs. This paper presents the result of a numerical study of a collimation system for the ESS linac.

MOPPR039

Development of Beam Position Monitor for PEFP Linac and Beam line

linac, proton, coupling, quadrupole

864

J.Y. Ryu, Y.-S. Cho, J.-H. Jang, H.S. Kim, H.-J. Kwon, K.T. Seol
KAERI, Daejon, Republic of Korea

Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government.
The development of the Beam Position Monitor (BPM) is in progress for the linac and beam lines of the Proton Engineering Frontier Project (PEFP). We choose a strip line BPM for the PEFP 20-MeV and 100-MeV beam lines in order to increase the sensitivity of the relatively long bunches in the beam lines. We also selected the same type BPM for the proton linac in the energy range between 20-MeV and 100-MeV. The prototype BPM was designed, fabricated and tested at KAERI site, where the 20-MeV linac was operated. To check the performance of the BPM, we performed the field mapping. The characteristics and test results of the BPM on the test bench as well as with 20-MeV proton beam will be presented in this paper.

MOPPR045

Beam Diagnostics for ESS

linac, target, diagnostics, instrumentation

882

A. Jansson, C. Böhme, B. Cheymol, H. Hassanzadegan, T.J. Shea, L. Tchelidze
ESS, Lund, Sweden

The European Spallation Source (ESS), to be built in the south of Sweden, will use a 2.5 GeV superconducting linac to produce the worlds most powerful neutron source. The project is currently in a pre-construction phase, during which the linac design is being updated. This paper describes the current plans for beam diagnostics in terms of requirements, number and locations of different systems, and possible technical solutions.

TUOBA02

Beam Commissioning and Operation of New Linac Injector for RIKEN RI-beam Factory

cyclotron, ion, linac, ECRIS

1071

K. Yamada, S. Arai, M. Fujimaki, T. Fujinawa, H. Fujisawa, N. Fukunishi, Y. Higurashi, E. Ikezawa, H. Imao, O. Kamigaito, M. Kase, M. Komiyama, K. Kumagai, T. Maie, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, Y. Watanabe, H. Yamasawa
RIKEN Nishina Center, Wako, Japan
A. Goto
NIRS, Chiba-shi, Japan
Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

A new linac injector called RILAC2* has successfully commissioned at the RIKEN RI beam factory (RIBF). The RILAC2 can accelerate very heavy ions with m/q of 7, such as 124Xe¹⁹⁺ and 238U³⁵⁺ from a 28 GHz superconducting ECR ion source**, up to an energy of 680 keV/nucleon in the cw mode. Ions are directory injected into the RIKEN Ring Cyclotron without charge stripping in order to increase the beam intensity, as well as performing independent RIBF experiments and super-heavy-element synthesis. The key features of RILAC2 are the powerful ECRIS, higher extraction voltage of the ECRIS compared to the voltage of the existing injector linac to reduce the space charge effect, improvement of the rf voltage and phase stability, improvement of the vacuum level to reduce the loss by charge exchange, and the compact equipments yet to be installed in the existing AVF cyclotron vault. The first beam acceleration was achieved on December 21, 2010. After the several beam acceleration tests in 2011, we started to operate the RILAC2 to supply beams for the RIBF experiments.
* O. Kamigaito et al., Proc. of PASJ3-LAM31, WP78, p. 502 (2006); K. Yamada et al., Proc. of IPAC'10, MOPD046, p.789 (2010).
** T. Nakagawa et al., Rev. Sci. Instrum. 79, 02A327 (2008).

Slides TUOBA02 [9.947 MB]

TUOBA03

H⁻ and Proton Beam Loss Comparison at SNS Superconducting Linac

proton, linac, quadrupole, ion

1074

A.P. Shishlo, A.V. Aleksandrov, J. Galambos, M.A. Plum
ORNL, Oak Ridge, Tennessee, USA
E. Laface
ESS, Lund, Sweden
V.A. Lebedev
Fermilab, Batavia, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
A comparison of beam loss in the superconducting part (SCL) of the Spallation Neutron Source (SNS) linac for H⁻ and protons is presented. During the experiment the nominal beam of negative hydrogen ions in the SCL was replaced by a proton beam created by insertion of a thin stripping carbon foil placed in the low energy section of the linac. The observed significant reduction in the beam loss for protons is explained by a domination of the intra-beam stripping mechanism of the beam loss for H-. The details of the experiment are discussed, and a preliminary estimation of the cross section of the reaction H⁻ + H⁻ -> H⁻ + H⁰ + e is presented.

Slides TUOBA03 [0.772 MB]

WEXA03

Accelerator Physics and Technology for ESS

linac, klystron, target, cryomodule

2073

H. Danared
ESS, Lund, Sweden

A conceptual design of the 2.5 GeV proton linac of the European Spallation Source, ESS, was presented in a Conceptual Design Report in early 2012. Work is now progressing towards a Technical Design Report at the end of 2012. Changes to the linac configuration during the last year include a somewhat longer DTL and a change to fully segmented cryomodules. This paper reviews the current design status of the accelerator and its subsystems.

Slides WEXA03 [15.485 MB]

THPPC010

Beam Start-up of J-PARC Linac after the Tohoku Earthquake

linac, quadrupole, acceleration, radiation

3293

M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
T. Maruta, A. Miura, H. Sako, J. Tamura, G.H. Wei
JAEA/J-PARC, Tokai-mura, Japan

The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant recovering effort including the realignment of most linac components, we have resumed the beam operation of J-PARC linac in December 2011. In this paper, we present the experience in the beam start-up tuning after the earthquake and the status of the linac operation thereafter.

THPPC050

Effects of Grids in Drift Tubes

beam-transport, impedance, proton, linac

3401

M. Okamura
BNL, Upton, Long Island, New York, USA
H. Yamauchi
Time Corporation, Hiroshima, Japan

In 2011, we upgraded a 200 MHz buncher in the proton injector for the AGS – RHIC complex. In the buncher we installed four grids made of tungsten to improve a transit time factor of the buncher. The grid installed drift tubes have 32 mm of inner diameter and the each grid consists of four quadrants. The quadrants were cut out precisely from 1mm thick tungsten plates by a CNC wire cutting EDM. In the conference the 3D electric field design and performance of the grid will be discussed.
Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.

THPPC069

Design, Test and Implementation of New 201.25 MHz Power Amplifier for the LANSCE Linac

cathode, electron, HOM, cavity

3446

J.T.M. Lyles, Z. Chen, J. Davis, A.C. Naranjo, D. Rees, G. M. Sandoval, Jr.
LANL, Los Alamos, New Mexico, USA
D. Baca, R.E. Bratton, R.D. Summers
Compa Industries, Inc., Los Alamos, New Mexico, USA
N.W. Brennan
Texas A&M University, College Station, Texas, USA

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
A new 201.25 MHz final power amplifier (FPA) has been designed, fabricated, and tested at Los Alamos Neutron Science Center (LANSCE). The prototype FPA has produced 3 MW peak and 250 kW of mean power with 15 dB of power gain and over 60% efficiency. It has been tested for several thousand hours with a load. A Thales TH628 Diacrode® electron tube is key to the performance of the new amplifier. It is configured with a full wavelength output circuit, having the lower main tuner situated ¾λ from the central electron beam region in the tube and the upper slave tuner ¼λ from the same point. The FPA is designed with input and output transmission line cavity circuits, grid decoupling circuits, an adjustable output coupler, DC blocking and RF bypassing capacitors, HOM suppressors, and a cooling system. A pair of production amplifiers are planned to be power-combined for up to 3.6 MW peak power at high duty factor. Three of these combined amplifiers will be installed in place of the original 1968-vintage amplifiers to return LANSCE operation to 12% beam duty factor with higher peak current than presently possible.

THPPC070

A High Power Test Facility for New 201.25 MHz Power Amplifiers and Components

power-supply, controls, status, linac

3449

J.T.M. Lyles, J. Davis, D. Rees, G. M. Sandoval, Jr., A. Steck, D.J. Vigil
LANL, Los Alamos, New Mexico, USA
D. Baca, R.E. Bratton, R.D. Summers
Compa Industries, Inc., Los Alamos, New Mexico, USA
N.W. Brennan
Texas A&M University, College Station, Texas, USA

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
A new test facility was designed and constructed at Los Alamos Neutron Science Center (LANSCE) for testing a new Thales TH628 Diacrode® final power amplifier and associated driver stages. Anode power requirements for the TH628 are 28 kV DC, with 190 Amperes in millisecond pulses. A 225 uF capacitor bank supplies this current demand, with a crowbar circuit to rapidly discharge 88 kJ of stored energy. Charging current was obtained by re-configuring a 2 MW beam power supply remaining from another project. The power tubes are operated with DC anode voltage, and beam pulsing is done with control grid bias switching at relatively low power. A new Fast Protect and Monitor System was designed to take samples of RF reflected power, anode HV, and various tube currents, with logic outputs to promptly remove high voltages, RF drive and beam pulsing during faults. The entire test system is controlled with a programmable logic controller, for normal startup sequencing, protection against loss of cooling, and operator GUI. This test facility has been used over the past year to test the amplifiers along with high power coaxial components such as hybrid couplers and various water loads.

THPPP034

Optimization of a CW RFQ Prototype

rfq, simulation, impedance, linac

3809

U. Bartz, J. Gerbig, H.C. Lenz, A. Schempp
IAP, Frankfurt am Main, Germany

A short RFQ prototype was built for RF-tests of high power RFQ structures. We studied thermal effects to determine critical points of the design. HF-simulations with CST Microwave Studio and measurements were done. The cw-tests with 20 kW/m RF-power and simulations of thermal effects with ALGOR were finished successfully. The optimization of some details of the RF design is on focus now. Results and the status of the project will be presented

THPPP036

First Measurements of an Coupled CH Power Cavity for the FAIR Proton Injector

cavity, linac, coupling, proton

3812

R. M. Brodhage, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
G. Clemente, L. Groening
GSI, Darmstadt, Germany

For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. For this second tank technical and mechanical investigations have been performed to develop a complete technical concept for manufacturing. In Spring 2011, the construction of the first power prototype has started. The main components of this cavity were ready for measurements in fall 2011. At that time, the cavity was tested with a preliminary aluminum drift tube structure, which will allow precise frequency and field tuning. This paper will report on the recent technical developments and achievements. It will outline the main tuning and commissioning steps towards that novel type of proton DTL and it will show very promising results of the latest measurements.

THPPP043

Installation of 100-MeV Proton Linac for PEFP

linac, proton, klystron, site

3832

Y.-S. Cho, S. Cha, J.S. Hong, J.-H. Jang, D.I. Kim, H.S. Kim, H.-J. Kwon, B.-S. Park, J.Y. Ryu, K.T. Seol, Y.-G. Song, S.P. Yun
KAERI, Daejon, Republic of Korea

Funding: This work was supported by the Ministry of Education, Science and Technology of the Korean Government.
The Proton Engineering Frontier Project (PEFP) at Korea Atomic Energy Research Institute (KAERI) is developing a 100-MeV proton linac in order to supply 20-MeV and 100-MeV proton beams to users for proton beam application. The linac consists of a 50-keV injector, a 3-MeV radio frequency quadrupole (RFQ) and a 100-MeV drift tube linac (DTL). The operation of the 20-MeV part of linac at Daejeon site was finished on November 2011. It was disassembled and moved to the Gyeongju site for installation as a low energy part of the linac. We completed the fabrication and test of the accelerating structures. The installation of the proton linac started in December 2011 at the new project site. The user service is scheduled for 2013 through the beam commissioning in 2012. This work summarized the installation status of the proton linac.

THPPP044

RF Set-up Scheme for PEFP DTL

linac, proton, rfq, simulation

3835

J.-H. Jang, Y.-S. Cho, H.S. Kim, H.-J. Kwon
KAERI, Daejon, Republic of Korea

Funding: This work was supported by the Ministry of Education, Science and Technology of the Korean Government.
The proton engineering frontier project (PEFP) is developing a 100-MeV proton linac which consists of a 50 keV injector, a 3-MeV radio frequency quadrupole (RFQ) and a 100-MeV drift tube linac (DTL). The installation of the linac was started in December 2011. The beam commissioning is scheduled for 2012. The phase scan signature method is a common technique to determine the rf set point including the amplitude and phase in DTL tanks. This work summarized the rf set-up scheme for PEFP DTL tanks by using the phase scan signature method.

THPPP046

ESS End-to-End Simulations: a Comparison Between IMPACT and MADX

linac, simulation, space-charge, cavity

3841

E. Laface, R. Miyamoto
ESS, Lund, Sweden
D.C. Plostinar, C.R. Prior
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The European Spallation Source will be a 5 MW superconducting proton linac for the production of spallation neutrons. It is composed of an ion source, a radio frequency quadrupole, a drift tube linac and a superconducting linac as well as the low, medium and high, energy beam transport sections. At present these components of the linac are in the design phase: the optimization of the accelerator parameters requires an intensive campaign of simulations to test the model of the machine under possible operational conditions. In this paper the results of simulations performed with the IMPACT and MADX-PTC codes are presented and a comparison is made between them and independent simulations using TraceWin. The dynamics of the beam envelope and single and multi-particle tracking are reported.

THPPP052

Modelling the ISIS 70 MeV Linac

linac, rfq, quadrupole, simulation

3859

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
A.W. Mitchell
University of Warwick, Coventry, United Kingdom

The ISIS linac consists of four DTL tanks that accelerate a 50 pps, 20 mA H⁻ beam up to 70 MeV before injecting it into an 800 MeV synchrotron. Over the last decades, the linac has proved to be a stable and reliable injector for ISIS, which is a significant achievement considering that two of the tanks are nearly 60 years old. At the time the machine was designed, the limited computing power available and the absence of modern modeling codes, made the creation of a complex simulation model almost impossible. However, over the last few years, computer tools have became an integral part of any accelerator design, so in this paper we present a beam dynamics model of the ISIS linac. A comparison between the simulation results and machine operation data will be discussed, as well as possible linac tuning scenarios and recommended upgrades based on the new model.

THPPP069

Double-Gap Rebuncher Cavity Design of SNS MEBT

cavity, simulation, linac, impedance

3898

K.R. Shin
ORNL RAD, Oak Ridge, Tennessee, USA
A.E. Fathy
University of Tennessee, Knoxville, Tennessee, USA
Y.W. Kang
ORNL, Oak Ridge, Tennessee, USA

A double-gap rebuncher cavity has been studied through design and analysis with computer simulations. This cavity shape is a two cell abridged form of drift tube linac (DTL), instead an omega form of existing single gap elliptical cavity. The cavity operates in TM010 mode, likewise the commonly used single-gap cavities in some medium energy beam transport (MEBT) line of proton accelerators. The new cavity is more power efficient even with slightly lower Q factor because of utilization of two interactive gaps. The breakdown field can be lowered with adjustment of gap and tube length ratio. Electromagnetic, beam envelope, and thermal simulations are presented with comparison to the properties of the conventional elliptical cavity.

THPPP071

Design of the ESS Accelerator

linac, klystron, target, cryomodule

3904

H. Danared
ESS, Lund, Sweden

The European Spallation Source, ESS, has produced a Conceptual Design Report at the end of 2011 which will evolve towards a Technical Design Report at the end of 2012. This paper is presented on behalf of the ESS Accelerator Design Update Collaboration and will describe the current design of the ESS linear accelerator.

THPPP085

End to End Beam Dynamics of the ESS Linac

linac, proton, target, quadrupole

3933

M. Eshraqi, H. Danared, A. Ponton
ESS, Lund, Sweden
I. Bustinduy
ESS Bilbao, Bilbao, Spain
L. Celona
INFN/LNS, Catania, Italy
M. Comunian
INFN/LNL, Legnaro (PD), Italy
A.I.S. Holm, S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark
J. Stovall
CERN, Geneva, Switzerland

The European Spallation Source, ESS, uses a linear accelerator to deliver a high intensity proton beam to the target station. The nominal beam power on target will be 5~MW at an energy of 2.5~GeV. We briefly describe the individual accelerating structures and transport lines through which we have carried out multiparticle beam dynamics simulations. We will present a review of the beam dynamics from the source to the target.

THPPR048

Construction of a BNCT Facility using an 8-MeV High Power Proton Linac in Tokai

neutron, proton, target, radioactivity

4083

H. Kobayashi, T. Kurihara, H. Matsumoto, M. Yoshioka
KEK, Ibaraki, Japan
T. Hashirano, F. Inoue, K. Sennyu, T. Sugano
MHI, Hiroshima, Japan
F. Hiraga, Y. Kiyanagi
Hokkaido University, Sapporo, Japan
H. Kumada
Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
A. Matsumura, H. Sakurai
Tsukuba University, Ibaraki, Japan
T. Nakamura, H. Nakashima, T. Shibata
JAEA, Ibaraki-ken, Japan
T. Ohba, Su. Tanaka
Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan

An accelerator-based BNCT (Boron Neutron Capture Therapy) facility is now under construction and the entire system including the patient treatment system will be installed in the Ibaraki Medical Center for Advanced Neutron Therapy (tentative name). The linac specification is 8 MeV with 10 mA of average current (80 kW) with a duty factor of 20%. The linac is composed of a 3-MeV RFQ and a drift-tube linac and can accelerate a peak current of 50 mA up to 8-MeV. The neutron producing target is a 0.5 mm thick beryllium disk 150 mm in diameter which is formed on a heat sink plate. The material components used in the neutron moderator system, including the target, should be selected to have a reduced residual radio-activity. Special attention should be paid to mitigate the swelling of target materials due to hydrogen implantation as well. The development of an accelerator-based BNCT suited for practical application requires input from a wide spread of technical specialties. To obtain the needed breath and strength, we have organized our team with contributing members from diverse institutes and companies. The research and development activities of this integrated team will be presented.