LINAC2012 - List of Keywords (DTL)

Paper	Title	Other Keywords	Page
MO3A01	Development of H-mode Linacs for the FAIR Project	linac, proton, ion, cavity	120
	G. Clemente, W.A. Barth, L. Groening, S. Mickat, B. Schlitt, W. Vinzenz GSI, Darmstadt, Germany R. M. Brodhage, M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany
	H-mode cavities offer outstanding shunt impedances at low beam energies and enable the acceleration of intense ion beams. Crossed-bar H-cavities extend these properties to energies even beyond 100 MeV. Thus, the designs of the new injector linacs for FAIR, i.e. a 70 MeV, 70 mA proton driver for pbar-production and a cw intermediate mass, superconducting ion linac are based on these novel cavities. Several prototypes (normal & super-conducting) have been built and successfully tested. Moreover, designs for a replacement of the 80 MV Alvarez section of the GSI - Unilac will be discussed to improve the capabilities as the future FAIR heavy ion injector.
	Slides MO3A01 [2.741 MB]

MO3A02	Commissioning of a New Injector for the RIKEN RI-Beam Factory	cyclotron, cavity, injection, rfq	125
	N. Sakamoto, M. Fujimaki, H. Hasebe, Y. Higurashi, O. Kamigaito, H. Okuno, K. Suda, T. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan R. Koyama SHI Accelerator Service Ltd., Tokyo, Japan
	A new injector for the RIKEN RI-Beam Factory (RIBF) has been fully commissioned since October 2011. The injector accelerates ions of m/q=6.8 up to 670 keV/u. In order to save the cost and space, a direct coupling scheme was adopted for rf coupling between the cavity and amplifier, based on an elaborate design with the Microwave Studio code. It has worked out very stably in these three months, making the uranium beam intensity higher by one order of magnitude. Moreover, it is now possible to operate the RIBF and GARIS facility for the super-heavy element synthesis independently.
	Slides MO3A02 [19.503 MB]

MOPB094	Simulation Study on the Longitudinal Bunch Shape Measurement by RF Chopper at J-PARC Linac	cavity, emittance, simulation, linac	395
	T. Maruta JAEA/J-PARC, Tokai-mura, Japan M. Ikegami J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	A RF chopper is placed in the medium energy transport section (MEBT1) at J-PARC linac. The chopper is normally driven at synchronous phase of 0 degree to give a maximum deflection. The chopper has two RF gaps and both of them deflect a beam bunch horizontally while RF is on. In the MEBT1 section, while we have a transverse emittance monitor, there is no longitudinal monitor. It is hard to newly place a longitudinal beam monitor there due to space limitation. We conduct a simulation which studies on the usability of the chopper to a longitudinal beam monitor. When the synchronous phase of the chopper is ± 90 degree, the longitudinal beam profile is projected to horizontal beam distribution. In this presentation, we introduce simulation results.

TU1A05	Status and Commissioning Plan of the PEFP 100-MeV Linear Accelerator	linac, proton, klystron, site	422
	H.-J. Kwon, Y.-S. Cho, J.-H. Jang, D.I. Kim, H.S. Kim, B.-S. Park, J.Y. Ryu, K.T. Seol, Y.-G. Song, S.P. Yun KAERI, Daejon, Republic of Korea
	Funding: Works supported by the Ministry of Education, Science and Technology of Korean Government. One of the goals of the Proton Engineering Frontier Project (PEFP) is to develop a 100 MeV proton linear accelerator, which consists of 50 keV proton injector, 3 MeV radio frequency quadrupole (RFQ), 20 MeV/100 MeV drift tube linac (DTL) and 20 MeV/100 MeV beam lines. The 100 MeV linear accelerator and beam line components have been installed in the tunnel and experimental hall. After the completion of the utility commissioning, the commissioning of the accelerator starts with a goal of the beam delivery to the 100 MeV target room located at the end of the beam line in 2012. In this paper, the status and commissioning plan of the PEFP 100 MeV linear accelerator are presented.
	Slides TU1A05 [6.795 MB]

TUPB035	A New Design of the RFQ Channel for GSI HITRAP Facility	rfq, simulation, ion, linac	555
	S.G. Yaramyshev, W.A. Barth, G. Clemente, L.A. Dahl, V. Gettmann, F. Herfurth, M. Kaiser, M.T. Maier, D. Neidherr, A. Orzhekhovskaya, H. Vormann, G. Vorobjev GSI, Darmstadt, Germany R. Repnow MPI-K, Heidelberg, Germany
	The HITRAP linac at GSI is designed to decelerate ions with mass to charge ratio of A/Z<3 from 4 MeV/u to 6 keV/u for experiments with ion traps. The particles are decelerated to 500 keV/u with an IH-DTL stucture and finally to 6 keV/u with a 4-rod RFQ. During commissioning stage the deceleration to approx. 500 keV/u was successfully demonstrated, while no particles behind the RFQ with an energy of 6 keV/u were observed. Dedicated simulations with DYNAMION code, based on 3D-fotometrie of the fabricated RFQ electrodes were successfully performed comprehending the commissioning results. In a second step the simulations have been experimentally confirmed at a test-stand (MPI, Heidelberg). An input energy, accepted by the RFQ channel is significantly higher than design value. For this reason the longitudinal beam emittance after deceleration with IH structure does not fit to the longitudinal RFQ acceptance. To solve this problem a new design of the RFQ channel with a correct input energy has been started. New RFQ parameters and the results of the beam dynamics simulations are presented in this paper.

TUPB036	Design of Re-Buncher Cavity for Heavy-ion LINAC in IMP	cavity, simulation, linac, impedance	558
	L.P. Sun, X. Du, Y. He, A. Shi, C. Zhang, Z.L. Zhang IMP, Lanzhou, People's Republic of China
	A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LNAC at HIRFL (the heavy ion research facility of Lanzhou) has been constructed. The re-buncher, which is used for beam longitudinal modulation and match between the RFQ and DTL, is designed to be operated in continuous wave (CW) mode at the Medium-Energy Beam-Transport (MEBT) line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented.

TUPB049	Superconducting Low Beta Niobium Resonator for Heavy Ions	linac, niobium, ion, heavy-ion	588
	P.N. Prakash, K.K. Mistri, A. Roy, J. Sacharias, S.S. Sonti IUAC, New Delhi, India
	For the high current injector at Inter-University Accelerator Centre, a new superconducting niobium resonator optimized for β = 0.05 operating at 97 MHz, has been designed and fabricated. This resonator has the highest frequency in its class among the superconducting structures designed for such low velocity particles. The resonator has been carefully modeled using Microwave Studio code to minimize the peak magnetic field in order to achieve high accelerating gradients in it. Even though the resonance frequency is high, the physical dimensions of the resonator are large enough to allow processing of its superconducting surface effectively. The mechanical design of the resonator has been modeled using ANSYS multiphysics to increase the frequency of the lowest mechanical eigenmode of the central co-axial line, and also reduce liquid helium induced pressure fluctuations in the resonator. Bead pull measurements have been performed on the niobium resonator and they match with the design values very well. Cold tests at 4.2 K will be performed in the next few weeks. This paper will briefly present the design of the low beta resonator and details of the results from the cold tests.

TUPB095	Design of Coupler for Direct Coupled Amplifier to Drift Tube Linac Cavities of the Injector RILAC2 for RIKEN RI Beam Factory	cavity, impedance, coupling, linac	684
	K. Suda, S. Arai, Y. Chiba, O. Kamigaito, M. Kase, H. Okuno, N. Sakamoto, Y. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan
	A new linac RILAC2 was constructed at RIKEN RI Beam Factory as an injector for very heavy ions such as uranium and xenon of a high mass to charge ratio m/q ∼ 7, but high intensity ions can be extracted from an ion source. Three drift tube linac cavities, operate in continuous wave mode at 36.5 MHz, have been designed and built. In order to reduce an installation area, and to save a construction cost, we adopted a direct coupling method for a power amplifier without using a long transmission line. A complicated design procedure was performed in order to take into account a change of resonant frequency of the cavity caused by a capacitance of a power tube used in the amplifier. A design of the coupler, as well as the cavity was performed using a three-dimensional electromagnetic calculation code, CST Microwave Studio (MWS). The measured input impedance seen from the amplifier (700 – 1100 Ω) was reproduced well by the calculation of MWS. Also, in order to examine MWS, a case of a coupling with 50 Ω were calculated. The coupling conditions obtained by MWS were compared with the measurement and a calculation with a lumped circuit model.

TUPB099	Input Coupler of the J-PARC DTL	coupling, vacuum, cavity, linac	690
	F. Naito, K. Nanmo, H. Tanaka KEK, Ibaraki, Japan K. Hirano, T. Ito JAEA/J-PARC, Tokai-mura, Japan
	Each tank of J-PARC DTL has two input couplers. The coupler has a movable coupling　loop with an capacitive element which increase the coupling with the tank. The loop position is the outside of the tank, where is the atmosphere. The tank vacuum is kept by the ceramic window on the wall for the coupler port. The ceramic is made of Aluminum oxide of 99.7 % purity. RF properties and the mechanical structure of the coupler were designed adequately in order to achieve the desired performance. We will report the design of the coupler in detail and the experiences for the practical operation of the DTL.

TUPB100	Recovery and Status Report of DTL/SDTL for the J-PARC After Earthquake	cavity, alignment, linac, target	693
	T. Ito, K. Hirano JAEA/LINAC, Ibaraki-ken, Japan F. Naito, K. Nanmo KEK, Ibaraki, Japan
	The J-PARC facilities had big damages because of the earthquake on March 11, 2011. The J-PARC linac in the tunnel had also damages. For instance the alignment of the cavity was deformed more than 40 mm and there had been observed about 0.2 mm in horizontal direction for a few DTs in the DTL. However, as the result of the recovery work which includes the re-alignment and re-conditioning of whole cavities, we were able to restart the beam acceleration of the linac. The stability of the DTL and SDTL has returned to the state before the earthquake except for a few tanks of SDTL. In this paper, we will present the recovery works from the earthquake and the operating status of the DTL and the SDTL.

TUPB101	Beam Loss Occurred at DTL Cavity in J-PARC Linac	radiation, cavity, linac, drift-tube-linac	696
	A. Miura, K. Hirano, T. Ito, T. Maruta JAEA/J-PARC, Tokai-mura, Japan M. Ikegami J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Miyao, F. Naito, K. Nanmo KEK, Ibaraki, Japan
	The beam operation of J-PARC linac was suspended until December 2011 due to the damage by the Tohoku earthquake in March 2011. After resumed the operations, we measured the residual radiation along with the beam line during a short interval. Because the higher residual radiation was detected at the surface of drift tube linac (DTL) cavity by radiation survey, we installed the scintillation beam loss monitors (BLM) at the points where the higher radiation was detected to understand the cause of the radiation. Even the DTL section is low energy part of the linac, fine structure of the beam loss was observed by the scintillation BLM. And we measured the beam loss occurred at the DTL with the parameters of beam orbit and cavity settings. Also, the BLM is employed for the linac tuning. In this paper, the result of the radiation measurement and beam loss signals obtained by the scintillation BLMs are presented.

TUPB103	CSNS DTL Prototyping and RF Tuning	cavity, linac, vacuum, quadrupole	702
	H.C. Liu, Q. Chen, S. Fu, K.Y. Gong, A.H. Li, J. Peng, Y.C. Xiao, X. Yin IHEP, Beijing, People's Republic of China
	The 324 MHz Alvarez-type Drift Tube Linac (DTL) for the China spallation neutron source will be used to accelerate the H⁻ ion beam of up to 15 mA peak current from 3 to 80 MeV. It consists of four independent tanks, of which the average length is about 8.6 m. Each tank is divided into three short unit tanks about 2.8 m in length for easy manufacture. A full-scale prototype of the first unit tank with 28 drift tubes containing electromagnetic quadrupoles has been constructed to validate the design and to demonstrate the technology. The overall features of the prototype in both key technology and RF tuning are presented. In particular, the influence of the post couplers was studied in the ramped field DTL.

TH2A03	Design and Construction of the Linac4 Accelerating Structures	linac, rfq, cavity, vacuum	778
	F. Gerigk, Y. Cuvet, A. Dallocchio, G. Favre, J.-M. Geisser, L. Gentini, J.-M. Giguet, S.J. Mathot, M. Polini, S. Ramberger, B. Riffaud, C. Rossi, P. Ugena Tirado, M. Vretenar, R. Wegner CERN, Geneva, Switzerland E. Kendjebulatov, Ya.G. Kruchkov, A.G. Tribendis BINP SB RAS, Novosibirsk, Russia M.Y. Naumenko RFNC-VNIITF, Snezhinsk, Chelyabinsk region, Russia
	The Linac4 project at CERN is at an advanced state of construction. Prototypes of the different types of accelerating structures (RFQ, DTL, CCDTL and pi-mode structures) have been built and are presently tested. This paper gives the status of the cavity production and reviews the RF and mechanical design of the various structure types. Furthermore the production and the first test results shall be presented.
	Slides TH2A03 [2.675 MB]

THPLB01	Linac Construction for China Spallation Neutron Source	linac, rfq, neutron, cavity	807
	S. Fu, J. Li, H.C. Liu, H.F. Ouyang, X. Yin IHEP, Beijing, People's Republic of China
	Construction of China Spallation Neutron Source(CSNS) has been launched in September 2011. CSNS accelerator will provide 100kW proton beam on a target at beam energy of 1.6GeV. It consists of an 80MeV H⁻ linac and 1.6GeV rapid cycling synchrotron. Based on the prototyping experience, CSNS linac, including the front end and four DTL tanks, has finalized the design and started procurement. In this paper, we will first present an outline of the CSNS accelerator in its design and construction plan. Then the major prototyping results of the linac will be presented. Finally the linac construction progress in recent will be updated.
	Slides THPLB01 [1.969 MB]

THPLB03	Front-End Linac Design and Beam Dynamics Simulations for MYRRHA	rfq, simulation, emittance, linac	813
	C. Zhang, H. Klein, D. Mäder, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede, M. Vossberg IAP, Frankfurt am Main, Germany
	Funding: Funded by the European Atomic Energy Community’s (Euratom) 7th Framework Programme under Grant Agreement n°269565. A 17MeV, 176MHz, and CW (Continuous Wave) proton linac is being developed as the front end of the driver accelerator for the MYRRHA facility in Mol, Belgium. Based on the promising preliminary design, further simulation and optimization studies have been performed with respect to code benchmarking, RFQ simulation using realistic LEBT output distributions, and an updated CH-DTL design with more detailed inter-tank configurations. This paper summarizes the new results.
	Slides THPLB03 [1.292 MB]

THPLB06	The New Option for a Front End of Ion Linac	rfq, ion, proton, linac	822
	A.D. Kovalenko JINR, Dubna, Moscow Region, Russia A. Kolomiets ITEP, Moscow, Russia
	The standard ion linac front-end consisting of RFQ, two tanks of accelerating IH-structures, MEBTs with matching and focusing elements is modified to achieve better performances. Special vane section that provides the same beam transformation as debuncher and quadrupole triplet is added within the RFQ tank, whereas superconducting focusing elements, solenoids, for example, are used between the IH - structure tanks. Test frond end was designed to provide the output beam energy up to 4 MeV/u for the particles with charge-to-mass ratio of 0.16 < q/m ≤ 1. Results of beam dynamics simulation are presented. Possible application of the considered scheme for the NICA facility at JINR (Dubna, Russia) is discussed.
	Slides THPLB06 [0.482 MB]

THPB005	Front-End Linac Design and Beam Dynamics Simulations for MYRRHA	rfq, simulation, emittance, linac	849
	C. Zhang, H. Klein, D. Mäder, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede, M. Vossberg IAP, Frankfurt am Main, Germany
	Funding: Funded by the European Atomic Energy Community’s (Euratom) 7th Framework Programme under Grant Agreement n°269565. A 17MeV, 176MHz, and CW (Continuous Wave) proton linac is being developed as the front end of the driver accelerator for the MYRRHA facility in Mol, Belgium. Based on the promising preliminary design, further simulation and optimization studies have been performed with respect to code benchmarking, RFQ simulation using realistic LEBT output distributions, and an updated CH-DTL design with more detailed inter-tank configurations. This paper summarizes the new results.

THPB006	Post Acceleration of Laser-generated Proton Bunches by a CH-DTL	proton, linac, laser, cavity	852
	A. Almomani, M. Droba, I. Hofmann, U. Ratzinger IAP, Frankfurt am Main, Germany
	Laser driven proton beam sources applying the TNSA process show interesting features in terms of energy and proton number per bunch. This makes them attractive as injectors into RF linacs at energies as high as 10 MeV or beyond. The combination shows attractive features like a very high particle number in a single bunch from the source and the flexibility and reliability of the rf linac to match the needs of a specified application. The approach aims on a very short matching section from the source target into the rf linac by one pulsed solenoid lens only. A crossbar H-type (CH - structure) is suggested because of its high acceleration gradient and efficiency at these beam energies. It is intended to realize the first cavity of the proposed CH - linac and to demonstrate the acceleration of a laser generated proton bunch within the LIGHT collaboration at GSI Darmstadt. Detailed beam and field simulations will be presented.

THPB008	A Coupled RFQ-IH Cavity for the Neutron Source FRANZ	rfq, cavity, coupling, simulation	858
	M. Heilmann, O. Meusel, D. Mäder, U. Ratzinger, A. Schempp, M. Schwarz IAP, Frankfurt am Main, Germany
	The Frankfurt neutron source FRANZ will deliver neutrons in the energy range from 1 to 500 keV with high pulsed intensities. A 2 MeV proton beam will produce protons via the 7Li(p,n)7Be reaction. The 175 MHz accelerator cavity consists of a 4-rod-RFQ coupled with an 8 gap interdigital H-type drift tube section, the total cavity length being 2.3m. The combined cavity will be powered by one RF amplifier to reduce investment and operation costs. The inductive power coupler will be at the RFQ part. The coupling into the IH - section is provided through a large aperture - mainly inductively. By CST - MWS - simulations as well as by an RF - model the voltage tuning along the cavity was investigated, and with special care the balance between both cavity sections. A first set of RFQ electrodes should allow to reach beam currents up to 50 mA in cw operation: The beam is pulsed with 100 ns, 250 kHz, while the cavity has to be operated cw due to the high rep. rate. The layout of the cavity cooling aims on a maximum accessible heat load of 200 kW.

THPB010	Progress in the Construction of Linac4 at CERN	linac, injection, rfq, klystron	864
	M. Vretenar, L. Arnaudon, P. Baudrenghien, G. Bellodi, C. Bertone, Y. Body, J.C. Broere, O. Brunner, M.C.L. Buzio, C. Carli, J.-P. Corso, J. Coupard, A. Dallocchio, N. Dos Santos, J.-F. Fuchs, A. Funken, R. Garoby, F. Gerigk, L. Hammouti, K. Hanke, J. Hansen, I. Kozsar, J.-B. Lallement, J. Lettry, A.M. Lombardi, L.A. Lopez Hernandez, C. Maglioni, S.J. Mathot, B. Mikulec, D. Nisbet, M.M. Paoluzzi, B. Puccio, U. Raich, S. Ramberger, F. Roncarolo, C. Rossi, N. Schwerg, R. Scrivens, G. Vandoni, J. Vollaire, R. Wegner, S. Weisz, Th. Zickler CERN, Geneva, Switzerland
	As first step of the LHC luminosity upgrade program CERN is building a new 160 MeV H¯ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the PS Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of a 3 MeV injector followed by 22 accelerating cavities of three different types. The general service infrastructure has been installed in the new tunnel and surface building and its commissioning is progressing; high power RF equipment is being installed in the hall and installations in the tunnel will start soon. Construction of the accelerator parts is in full swing involving industry, the CERN workshops and a network of international collaborations. The injector section including a newly designed and built H¯ source, a 3-m long RFQ and a chopping line is being commissioned in a dedicated test stand. Beam commissioning of the linac will take place in steps of increasing energy between 2013 and 2014. From end of 2014 Linac4 could deliver 50 MeV protons in case of Linac2 failure, while 160 MeV H¯ could be injected into the PSB from end of 2015; the exact start of the LHC shut-down required for connection will be coordinated with its experiments.

THPB012	High Resolution Emittance Measurements at SNS Front End	emittance, linac, coupling, target	870
	A.P. Zhukov, A.V. Aleksandrov ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. Spallation Neutron Source (SNS) linac accelerates an H⁻ beam from 2.5MeV up to 1GeV. Recently the emittance scanner in the MEBT (2.5 MeV) was upgraded. In addition to the slit - harp measurement we now can use a slit installed on the same actuator as the harp. In combination with a faraday cup located downstream in DTL part of the linac it represents a classical slit-slit emittance measurement device. While a slit – slit scan takes much longer time, it is immune to harp related problems such as wire cross talk and thus looks promising for accurate halo measurements. Time resolution of the new device seems to be sufficient to estimate amount of the beam in the chopper gap (the scanner is downstream of the chopper) and probably measure its emittance. The paper describes initial measurements with new device and some model validation data.

THPB022	Beam Phase Measurement for PEFP Linear Accelerator	linac, simulation, LLRF, proton	894
	H.S. Kim, Y.-S. Cho, J.-H. Jang, H.-J. Kwon, J.Y. Ryu, K.T. Seol, Y.-G. Song KAERI, Daejon, Republic of Korea
	Funding: Works supported by the Ministry of Education, Science and Technology of Korean Government. According to the commissioning plan of the PEFP proton linac, an accurate measurement of beam phase is essential, especially for setting up the RF operating parameters of DTL. Beam position monitors (BPMs) installed between DTL tanks can provide information about the beam phase as well as about the beam transverse position. By using a BPM as a beam phase monitor, beam phase can be measured without additional devices on the linac or the beam line. The signals from 4 electrodes in the BPM can be summed by using a 4-way RF combiner, by which the effect of the transverse beam offset on the phase measurement can be eliminated. The combined BPM signal (350 MHz) is mixed with LO signal (300 MHz) and down-converted to IF signal (50 MHz), then fed into the signal processing unit, where the phase information is extracted by using IQ demodulation method with a sampling frequency of 40 MHz. In this paper, the beam phase measurement system and signal processing scheme will be presented.

THPB023	Linac Construction for China Spallation Neutron Source	linac, rfq, neutron, cavity	897
	S. Fu, J. Li, H.C. Liu, H.F. Ouyang, X. Yin IHEP, Beijing, People's Republic of China
	Construction of China Spallation Neutron Source(CSNS) has been launched in September 2011. CSNS accelerator will provide 100kW proton beam on a target at beam energy of 1.6GeV. It consists of an 80MeV H⁻ linac and 1.6GeV rapid cycling synchrotron. Based on the prototyping experience, CSNS linac, including the front end and four DTL tanks, has finalized the design and started procurement. In this paper, we will first present an outline of the CSNS accelerator in its design and construction plan. Then the major prototyping results of the linac will be presented. Finally the linac construction progress in recent will be updated.

THPB029	The ESS RFQ Beam Dynamics Design	rfq, linac, proton, emittance	915
	A. Ponton ESS, Lund, Sweden
	to be added

THPB030	DTL Design for ESS	linac, simulation, proton, drift-tube-linac	918
	M. Comunian, F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy R. De Prisco Lund University, Lund, Sweden M. Eshraqi ESS, Lund, Sweden P. Mereu INFN-Torino, Torino, Italy
	In the present design of the European Spallation Source (ESS) accelerator, the Drift Tube Linac (DTL) will accelerate a proton beam of 50 mA pulse peak current from 3 to 80 MeV. It is designed to operate at 352.2 MHz, with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period). Permanent magnet quadrupoles (PMQs) are used as focusing elements in a FODO lattice scheme, which leaves space for steerers and diagnostics . In this paper beam dynamics studies and preliminary RF design are shown, including constraints in terms of quadrupole dimensions, total length, field stability, RF power, peak electric field.

THPB032	Beam Dynamics Design Aspects for a Proposed 800 MeV H⁻ ISIS Linac	linac, cavity, quadrupole, rfq	924
	D.C. Plostinar, C.R. Prior, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H⁻ linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined with an emphasis on the beam dynamics design philosophy. The linac consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV.

THPB034	Status of the FAIR 70 MeV Proton Linac	proton, linac, rfq, cavity	927
	L. Groening, W.A. Barth, R. Berezov, G. Clemente, P. Forck, R. Hollinger, A. Krämer, C. Mühle, J. Pfister, G. Schreiber, J. Trüller, W. Vinzenz, C. Will GSI, Darmstadt, Germany N. Chauvin, O. Delferrière, O. Tuske CEA/IRFU, Gif-sur-Yvette, France B. Koubek, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede IAP, Frankfurt am Main, Germany B. Launé, J. Lesrel IPN, Orsay, France C.S. Simon CEA/DSM/IRFU, France
	To provide the primary proton beam for the FAIR anti-proton research program, a 70 MeV, 70 mA linac is currently under design & construction at GSI. The nc machine comprises an ECR source, a 3 MeV RFQ, and a DTL based on CH-cavities. Up to 36 MeV pairs of rf-coupled cavities (CCH) are used. A prototype cavity has been built and is prepared for high power rf-testing. An overview of the status as well as on the perspectives of the project is given.

THPB036	The New Option for a Front End of Ion Linac	rfq, ion, proton, linac	933
	A.D. Kovalenko JINR, Dubna, Moscow Region, Russia A. Kolomiets ITEP, Moscow, Russia
	The standard ion linac front-end consisting of RFQ, two tanks of accelerating IH-structures, MEBTs with matching and focusing elements is modified to achieve better performances. Special vane section that provides the same beam transformation as debuncher and quadrupole triplet is added within the RFQ tank, whereas superconducting focusing elements, solenoids, for example, are used between the IH - structure tanks. Test frond end was designed to provide the output beam energy up to 4 MeV/u for the particles with charge-to-mass ratio of 0.16 < q/m ≤ 1. Results of beam dynamics simulation are presented. Possible application of the considered scheme for the NICA facility at JINR (Dubna, Russia) is discussed.

FR1A04	In Flight Ion Separation using a Linac Chain	rfq, linac, ISAC, TRIUMF	1059
	M. Marchetto, F. Ames, B. Davids, R.E. Laxdal, A.C. Morton TRIUMF, Vancouver, Canada
	The ISAC accelerator complex now can accelerate radioactive heavy ion beams to above the Coulomb Barrier. Recently an ECR type charge state booster has been added to allow the acceleration of radioactive beams with masses A>30. A characteristic of the ECR source is the efficient ionization of background species that can overwhelm the low intensity RIB beam. The long linac chain at ISAC can be used to provide some in flight separation both in time domain and in spatial domain analogous to fragment separators at in-flight fragmentation facilities. The talk will summarize the work done at TRIUMF to develop tools to aid in the filtration and diagnosis of beam purity in the post acceleration of charge bred beams. Marco Marchetto has been leading this effort.
	Slides FR1A04 [24.174 MB]

FR2A01	Recovery of the J-PARC Linac from the Earthquake	linac, vacuum, ion, rfq	1069
	K. Hasegawa J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Following the amazingly quick recovery from the disastrous earthquake in March 2011, and in the interests of promoting robust designs of linacs, it would be interesting to learn what the J-PARC team reckons are the key features of accelerator design and construction that lead to strong and reliable hardware.
	Slides FR2A01 [3.928 MB]

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MO3A01

Development of H-mode Linacs for the FAIR Project

linac, proton, ion, cavity

120

G. Clemente, W.A. Barth, L. Groening, S. Mickat, B. Schlitt, W. Vinzenz
GSI, Darmstadt, Germany
R. M. Brodhage, M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany

H-mode cavities offer outstanding shunt impedances at low beam energies and enable the acceleration of intense ion beams. Crossed-bar H-cavities extend these properties to energies even beyond 100 MeV. Thus, the designs of the new injector linacs for FAIR, i.e. a 70 MeV, 70 mA proton driver for pbar-production and a cw intermediate mass, superconducting ion linac are based on these novel cavities. Several prototypes (normal & super-conducting) have been built and successfully tested. Moreover, designs for a replacement of the 80 MV Alvarez section of the GSI - Unilac will be discussed to improve the capabilities as the future FAIR heavy ion injector.

Slides MO3A01 [2.741 MB]

MO3A02

Commissioning of a New Injector for the RIKEN RI-Beam Factory

cyclotron, cavity, injection, rfq

125

N. Sakamoto, M. Fujimaki, H. Hasebe, Y. Higurashi, O. Kamigaito, H. Okuno, K. Suda, T. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
R. Koyama
SHI Accelerator Service Ltd., Tokyo, Japan

A new injector for the RIKEN RI-Beam Factory (RIBF) has been fully commissioned since October 2011. The injector accelerates ions of m/q=6.8 up to 670 keV/u. In order to save the cost and space, a direct coupling scheme was adopted for rf coupling between the cavity and amplifier, based on an elaborate design with the Microwave Studio code. It has worked out very stably in these three months, making the uranium beam intensity higher by one order of magnitude. Moreover, it is now possible to operate the RIBF and GARIS facility for the super-heavy element synthesis independently.

Slides MO3A02 [19.503 MB]

MOPB094

Simulation Study on the Longitudinal Bunch Shape Measurement by RF Chopper at J-PARC Linac

cavity, emittance, simulation, linac

395

T. Maruta
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

A RF chopper is placed in the medium energy transport section (MEBT1) at J-PARC linac. The chopper is normally driven at synchronous phase of 0 degree to give a maximum deflection. The chopper has two RF gaps and both of them deflect a beam bunch horizontally while RF is on. In the MEBT1 section, while we have a transverse emittance monitor, there is no longitudinal monitor. It is hard to newly place a longitudinal beam monitor there due to space limitation. We conduct a simulation which studies on the usability of the chopper to a longitudinal beam monitor. When the synchronous phase of the chopper is ± 90 degree, the longitudinal beam profile is projected to horizontal beam distribution. In this presentation, we introduce simulation results.

TU1A05

Status and Commissioning Plan of the PEFP 100-MeV Linear Accelerator

linac, proton, klystron, site

422

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

Funding: Works supported by the Ministry of Education, Science and Technology of Korean Government.
One of the goals of the Proton Engineering Frontier Project (PEFP) is to develop a 100 MeV proton linear accelerator, which consists of 50 keV proton injector, 3 MeV radio frequency quadrupole (RFQ), 20 MeV/100 MeV drift tube linac (DTL) and 20 MeV/100 MeV beam lines. The 100 MeV linear accelerator and beam line components have been installed in the tunnel and experimental hall. After the completion of the utility commissioning, the commissioning of the accelerator starts with a goal of the beam delivery to the 100 MeV target room located at the end of the beam line in 2012. In this paper, the status and commissioning plan of the PEFP 100 MeV linear accelerator are presented.

Slides TU1A05 [6.795 MB]

TUPB035

A New Design of the RFQ Channel for GSI HITRAP Facility

rfq, simulation, ion, linac

555

S.G. Yaramyshev, W.A. Barth, G. Clemente, L.A. Dahl, V. Gettmann, F. Herfurth, M. Kaiser, M.T. Maier, D. Neidherr, A. Orzhekhovskaya, H. Vormann, G. Vorobjev
GSI, Darmstadt, Germany
R. Repnow
MPI-K, Heidelberg, Germany

The HITRAP linac at GSI is designed to decelerate ions with mass to charge ratio of A/Z<3 from 4 MeV/u to 6 keV/u for experiments with ion traps. The particles are decelerated to 500 keV/u with an IH-DTL stucture and finally to 6 keV/u with a 4-rod RFQ. During commissioning stage the deceleration to approx. 500 keV/u was successfully demonstrated, while no particles behind the RFQ with an energy of 6 keV/u were observed. Dedicated simulations with DYNAMION code, based on 3D-fotometrie of the fabricated RFQ electrodes were successfully performed comprehending the commissioning results. In a second step the simulations have been experimentally confirmed at a test-stand (MPI, Heidelberg). An input energy, accepted by the RFQ channel is significantly higher than design value. For this reason the longitudinal beam emittance after deceleration with IH structure does not fit to the longitudinal RFQ acceptance. To solve this problem a new design of the RFQ channel with a correct input energy has been started. New RFQ parameters and the results of the beam dynamics simulations are presented in this paper.

TUPB036

Design of Re-Buncher Cavity for Heavy-ion LINAC in IMP

cavity, simulation, linac, impedance

558

L.P. Sun, X. Du, Y. He, A. Shi, C. Zhang, Z.L. Zhang
IMP, Lanzhou, People's Republic of China

A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LNAC at HIRFL (the heavy ion research facility of Lanzhou) has been constructed. The re-buncher, which is used for beam longitudinal modulation and match between the RFQ and DTL, is designed to be operated in continuous wave (CW) mode at the Medium-Energy Beam-Transport (MEBT) line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented.

TUPB049

Superconducting Low Beta Niobium Resonator for Heavy Ions

linac, niobium, ion, heavy-ion

588

P.N. Prakash, K.K. Mistri, A. Roy, J. Sacharias, S.S. Sonti
IUAC, New Delhi, India

For the high current injector at Inter-University Accelerator Centre, a new superconducting niobium resonator optimized for β = 0.05 operating at 97 MHz, has been designed and fabricated. This resonator has the highest frequency in its class among the superconducting structures designed for such low velocity particles. The resonator has been carefully modeled using Microwave Studio code to minimize the peak magnetic field in order to achieve high accelerating gradients in it. Even though the resonance frequency is high, the physical dimensions of the resonator are large enough to allow processing of its superconducting surface effectively. The mechanical design of the resonator has been modeled using ANSYS multiphysics to increase the frequency of the lowest mechanical eigenmode of the central co-axial line, and also reduce liquid helium induced pressure fluctuations in the resonator. Bead pull measurements have been performed on the niobium resonator and they match with the design values very well. Cold tests at 4.2 K will be performed in the next few weeks. This paper will briefly present the design of the low beta resonator and details of the results from the cold tests.

TUPB095

Design of Coupler for Direct Coupled Amplifier to Drift Tube Linac Cavities of the Injector RILAC2 for RIKEN RI Beam Factory

cavity, impedance, coupling, linac

684

K. Suda, S. Arai, Y. Chiba, O. Kamigaito, M. Kase, H. Okuno, N. Sakamoto, Y. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan

A new linac RILAC2 was constructed at RIKEN RI Beam Factory as an injector for very heavy ions such as uranium and xenon of a high mass to charge ratio m/q ∼ 7, but high intensity ions can be extracted from an ion source. Three drift tube linac cavities, operate in continuous wave mode at 36.5 MHz, have been designed and built. In order to reduce an installation area, and to save a construction cost, we adopted a direct coupling method for a power amplifier without using a long transmission line. A complicated design procedure was performed in order to take into account a change of resonant frequency of the cavity caused by a capacitance of a power tube used in the amplifier. A design of the coupler, as well as the cavity was performed using a three-dimensional electromagnetic calculation code, CST Microwave Studio (MWS). The measured input impedance seen from the amplifier (700 – 1100 Ω) was reproduced well by the calculation of MWS. Also, in order to examine MWS, a case of a coupling with 50 Ω were calculated. The coupling conditions obtained by MWS were compared with the measurement and a calculation with a lumped circuit model.

TUPB099

Input Coupler of the J-PARC DTL

coupling, vacuum, cavity, linac

690

F. Naito, K. Nanmo, H. Tanaka
KEK, Ibaraki, Japan
K. Hirano, T. Ito
JAEA/J-PARC, Tokai-mura, Japan

Each tank of J-PARC DTL has two input couplers. The coupler has a movable coupling　loop with an capacitive element which increase the coupling with the tank. The loop position is the outside of the tank, where is the atmosphere. The tank vacuum is kept by the ceramic window on the wall for the coupler port. The ceramic is made of Aluminum oxide of 99.7 % purity. RF properties and the mechanical structure of the coupler were designed adequately in order to achieve the desired performance. We will report the design of the coupler in detail and the experiences for the practical operation of the DTL.

TUPB100

Recovery and Status Report of DTL/SDTL for the J-PARC After Earthquake

cavity, alignment, linac, target

693

T. Ito, K. Hirano
JAEA/LINAC, Ibaraki-ken, Japan
F. Naito, K. Nanmo
KEK, Ibaraki, Japan

The J-PARC facilities had big damages because of the earthquake on March 11, 2011. The J-PARC linac in the tunnel had also damages. For instance the alignment of the cavity was deformed more than 40 mm and there had been observed about 0.2 mm in horizontal direction for a few DTs in the DTL. However, as the result of the recovery work which includes the re-alignment and re-conditioning of whole cavities, we were able to restart the beam acceleration of the linac. The stability of the DTL and SDTL has returned to the state before the earthquake except for a few tanks of SDTL. In this paper, we will present the recovery works from the earthquake and the operating status of the DTL and the SDTL.

TUPB101

Beam Loss Occurred at DTL Cavity in J-PARC Linac

radiation, cavity, linac, drift-tube-linac

696

A. Miura, K. Hirano, T. Ito, T. Maruta
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Miyao, F. Naito, K. Nanmo
KEK, Ibaraki, Japan

The beam operation of J-PARC linac was suspended until December 2011 due to the damage by the Tohoku earthquake in March 2011. After resumed the operations, we measured the residual radiation along with the beam line during a short interval. Because the higher residual radiation was detected at the surface of drift tube linac (DTL) cavity by radiation survey, we installed the scintillation beam loss monitors (BLM) at the points where the higher radiation was detected to understand the cause of the radiation. Even the DTL section is low energy part of the linac, fine structure of the beam loss was observed by the scintillation BLM. And we measured the beam loss occurred at the DTL with the parameters of beam orbit and cavity settings. Also, the BLM is employed for the linac tuning. In this paper, the result of the radiation measurement and beam loss signals obtained by the scintillation BLMs are presented.

TUPB103

CSNS DTL Prototyping and RF Tuning

cavity, linac, vacuum, quadrupole

702

H.C. Liu, Q. Chen, S. Fu, K.Y. Gong, A.H. Li, J. Peng, Y.C. Xiao, X. Yin
IHEP, Beijing, People's Republic of China

The 324 MHz Alvarez-type Drift Tube Linac (DTL) for the China spallation neutron source will be used to accelerate the H⁻ ion beam of up to 15 mA peak current from 3 to 80 MeV. It consists of four independent tanks, of which the average length is about 8.6 m. Each tank is divided into three short unit tanks about 2.8 m in length for easy manufacture. A full-scale prototype of the first unit tank with 28 drift tubes containing electromagnetic quadrupoles has been constructed to validate the design and to demonstrate the technology. The overall features of the prototype in both key technology and RF tuning are presented. In particular, the influence of the post couplers was studied in the ramped field DTL.

TH2A03

Design and Construction of the Linac4 Accelerating Structures

linac, rfq, cavity, vacuum

778

F. Gerigk, Y. Cuvet, A. Dallocchio, G. Favre, J.-M. Geisser, L. Gentini, J.-M. Giguet, S.J. Mathot, M. Polini, S. Ramberger, B. Riffaud, C. Rossi, P. Ugena Tirado, M. Vretenar, R. Wegner
CERN, Geneva, Switzerland
E. Kendjebulatov, Ya.G. Kruchkov, A.G. Tribendis
BINP SB RAS, Novosibirsk, Russia
M.Y. Naumenko
RFNC-VNIITF, Snezhinsk, Chelyabinsk region, Russia

The Linac4 project at CERN is at an advanced state of construction. Prototypes of the different types of accelerating structures (RFQ, DTL, CCDTL and pi-mode structures) have been built and are presently tested. This paper gives the status of the cavity production and reviews the RF and mechanical design of the various structure types. Furthermore the production and the first test results shall be presented.

Slides TH2A03 [2.675 MB]

THPLB01

Linac Construction for China Spallation Neutron Source

linac, rfq, neutron, cavity

807

S. Fu, J. Li, H.C. Liu, H.F. Ouyang, X. Yin
IHEP, Beijing, People's Republic of China

Construction of China Spallation Neutron Source(CSNS) has been launched in September 2011. CSNS accelerator will provide 100kW proton beam on a target at beam energy of 1.6GeV. It consists of an 80MeV H⁻ linac and 1.6GeV rapid cycling synchrotron. Based on the prototyping experience, CSNS linac, including the front end and four DTL tanks, has finalized the design and started procurement. In this paper, we will first present an outline of the CSNS accelerator in its design and construction plan. Then the major prototyping results of the linac will be presented. Finally the linac construction progress in recent will be updated.

Slides THPLB01 [1.969 MB]

THPLB03

Front-End Linac Design and Beam Dynamics Simulations for MYRRHA

rfq, simulation, emittance, linac

813

C. Zhang, H. Klein, D. Mäder, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede, M. Vossberg
IAP, Frankfurt am Main, Germany

Funding: Funded by the European Atomic Energy Community’s (Euratom) 7th Framework Programme under Grant Agreement n°269565.
A 17MeV, 176MHz, and CW (Continuous Wave) proton linac is being developed as the front end of the driver accelerator for the MYRRHA facility in Mol, Belgium. Based on the promising preliminary design, further simulation and optimization studies have been performed with respect to code benchmarking, RFQ simulation using realistic LEBT output distributions, and an updated CH-DTL design with more detailed inter-tank configurations. This paper summarizes the new results.

Slides THPLB03 [1.292 MB]

THPLB06

The New Option for a Front End of Ion Linac

rfq, ion, proton, linac

822

A.D. Kovalenko
JINR, Dubna, Moscow Region, Russia
A. Kolomiets
ITEP, Moscow, Russia

The standard ion linac front-end consisting of RFQ, two tanks of accelerating IH-structures, MEBTs with matching and focusing elements is modified to achieve better performances. Special vane section that provides the same beam transformation as debuncher and quadrupole triplet is added within the RFQ tank, whereas superconducting focusing elements, solenoids, for example, are used between the IH - structure tanks. Test frond end was designed to provide the output beam energy up to 4 MeV/u for the particles with charge-to-mass ratio of 0.16 < q/m ≤ 1. Results of beam dynamics simulation are presented. Possible application of the considered scheme for the NICA facility at JINR (Dubna, Russia) is discussed.

Slides THPLB06 [0.482 MB]

THPB005

Front-End Linac Design and Beam Dynamics Simulations for MYRRHA

rfq, simulation, emittance, linac

849

C. Zhang, H. Klein, D. Mäder, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede, M. Vossberg
IAP, Frankfurt am Main, Germany

Funding: Funded by the European Atomic Energy Community’s (Euratom) 7th Framework Programme under Grant Agreement n°269565.
A 17MeV, 176MHz, and CW (Continuous Wave) proton linac is being developed as the front end of the driver accelerator for the MYRRHA facility in Mol, Belgium. Based on the promising preliminary design, further simulation and optimization studies have been performed with respect to code benchmarking, RFQ simulation using realistic LEBT output distributions, and an updated CH-DTL design with more detailed inter-tank configurations. This paper summarizes the new results.

THPB006

Post Acceleration of Laser-generated Proton Bunches by a CH-DTL

proton, linac, laser, cavity

852

A. Almomani, M. Droba, I. Hofmann, U. Ratzinger
IAP, Frankfurt am Main, Germany

Laser driven proton beam sources applying the TNSA process show interesting features in terms of energy and proton number per bunch. This makes them attractive as injectors into RF linacs at energies as high as 10 MeV or beyond. The combination shows attractive features like a very high particle number in a single bunch from the source and the flexibility and reliability of the rf linac to match the needs of a specified application. The approach aims on a very short matching section from the source target into the rf linac by one pulsed solenoid lens only. A crossbar H-type (CH - structure) is suggested because of its high acceleration gradient and efficiency at these beam energies. It is intended to realize the first cavity of the proposed CH - linac and to demonstrate the acceleration of a laser generated proton bunch within the LIGHT collaboration at GSI Darmstadt. Detailed beam and field simulations will be presented.

THPB008

A Coupled RFQ-IH Cavity for the Neutron Source FRANZ

rfq, cavity, coupling, simulation

858

M. Heilmann, O. Meusel, D. Mäder, U. Ratzinger, A. Schempp, M. Schwarz
IAP, Frankfurt am Main, Germany

The Frankfurt neutron source FRANZ will deliver neutrons in the energy range from 1 to 500 keV with high pulsed intensities. A 2 MeV proton beam will produce protons via the 7Li(p,n)7Be reaction. The 175 MHz accelerator cavity consists of a 4-rod-RFQ coupled with an 8 gap interdigital H-type drift tube section, the total cavity length being 2.3m. The combined cavity will be powered by one RF amplifier to reduce investment and operation costs. The inductive power coupler will be at the RFQ part. The coupling into the IH - section is provided through a large aperture - mainly inductively. By CST - MWS - simulations as well as by an RF - model the voltage tuning along the cavity was investigated, and with special care the balance between both cavity sections. A first set of RFQ electrodes should allow to reach beam currents up to 50 mA in cw operation: The beam is pulsed with 100 ns, 250 kHz, while the cavity has to be operated cw due to the high rep. rate. The layout of the cavity cooling aims on a maximum accessible heat load of 200 kW.

THPB010

Progress in the Construction of Linac4 at CERN

linac, injection, rfq, klystron

864

M. Vretenar, L. Arnaudon, P. Baudrenghien, G. Bellodi, C. Bertone, Y. Body, J.C. Broere, O. Brunner, M.C.L. Buzio, C. Carli, J.-P. Corso, J. Coupard, A. Dallocchio, N. Dos Santos, J.-F. Fuchs, A. Funken, R. Garoby, F. Gerigk, L. Hammouti, K. Hanke, J. Hansen, I. Kozsar, J.-B. Lallement, J. Lettry, A.M. Lombardi, L.A. Lopez Hernandez, C. Maglioni, S.J. Mathot, B. Mikulec, D. Nisbet, M.M. Paoluzzi, B. Puccio, U. Raich, S. Ramberger, F. Roncarolo, C. Rossi, N. Schwerg, R. Scrivens, G. Vandoni, J. Vollaire, R. Wegner, S. Weisz, Th. Zickler
CERN, Geneva, Switzerland

As first step of the LHC luminosity upgrade program CERN is building a new 160 MeV H¯ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the PS Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of a 3 MeV injector followed by 22 accelerating cavities of three different types. The general service infrastructure has been installed in the new tunnel and surface building and its commissioning is progressing; high power RF equipment is being installed in the hall and installations in the tunnel will start soon. Construction of the accelerator parts is in full swing involving industry, the CERN workshops and a network of international collaborations. The injector section including a newly designed and built H¯ source, a 3-m long RFQ and a chopping line is being commissioned in a dedicated test stand. Beam commissioning of the linac will take place in steps of increasing energy between 2013 and 2014. From end of 2014 Linac4 could deliver 50 MeV protons in case of Linac2 failure, while 160 MeV H¯ could be injected into the PSB from end of 2015; the exact start of the LHC shut-down required for connection will be coordinated with its experiments.

THPB012

High Resolution Emittance Measurements at SNS Front End

emittance, linac, coupling, target

870

A.P. Zhukov, A.V. Aleksandrov
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
Spallation Neutron Source (SNS) linac accelerates an H⁻ beam from 2.5MeV up to 1GeV. Recently the emittance scanner in the MEBT (2.5 MeV) was upgraded. In addition to the slit - harp measurement we now can use a slit installed on the same actuator as the harp. In combination with a faraday cup located downstream in DTL part of the linac it represents a classical slit-slit emittance measurement device. While a slit – slit scan takes much longer time, it is immune to harp related problems such as wire cross talk and thus looks promising for accurate halo measurements. Time resolution of the new device seems to be sufficient to estimate amount of the beam in the chopper gap (the scanner is downstream of the chopper) and probably measure its emittance. The paper describes initial measurements with new device and some model validation data.

THPB022

Beam Phase Measurement for PEFP Linear Accelerator

linac, simulation, LLRF, proton

894

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

Funding: Works supported by the Ministry of Education, Science and Technology of Korean Government.
According to the commissioning plan of the PEFP proton linac, an accurate measurement of beam phase is essential, especially for setting up the RF operating parameters of DTL. Beam position monitors (BPMs) installed between DTL tanks can provide information about the beam phase as well as about the beam transverse position. By using a BPM as a beam phase monitor, beam phase can be measured without additional devices on the linac or the beam line. The signals from 4 electrodes in the BPM can be summed by using a 4-way RF combiner, by which the effect of the transverse beam offset on the phase measurement can be eliminated. The combined BPM signal (350 MHz) is mixed with LO signal (300 MHz) and down-converted to IF signal (50 MHz), then fed into the signal processing unit, where the phase information is extracted by using IQ demodulation method with a sampling frequency of 40 MHz. In this paper, the beam phase measurement system and signal processing scheme will be presented.

THPB023

Linac Construction for China Spallation Neutron Source

linac, rfq, neutron, cavity

897

S. Fu, J. Li, H.C. Liu, H.F. Ouyang, X. Yin
IHEP, Beijing, People's Republic of China

Construction of China Spallation Neutron Source(CSNS) has been launched in September 2011. CSNS accelerator will provide 100kW proton beam on a target at beam energy of 1.6GeV. It consists of an 80MeV H⁻ linac and 1.6GeV rapid cycling synchrotron. Based on the prototyping experience, CSNS linac, including the front end and four DTL tanks, has finalized the design and started procurement. In this paper, we will first present an outline of the CSNS accelerator in its design and construction plan. Then the major prototyping results of the linac will be presented. Finally the linac construction progress in recent will be updated.

THPB029

The ESS RFQ Beam Dynamics Design

rfq, linac, proton, emittance

915

A. Ponton
ESS, Lund, Sweden

to be added

THPB030

DTL Design for ESS

linac, simulation, proton, drift-tube-linac

918

M. Comunian, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
R. De Prisco
Lund University, Lund, Sweden
M. Eshraqi
ESS, Lund, Sweden
P. Mereu
INFN-Torino, Torino, Italy

In the present design of the European Spallation Source (ESS) accelerator, the Drift Tube Linac (DTL) will accelerate a proton beam of 50 mA pulse peak current from 3 to 80 MeV. It is designed to operate at 352.2 MHz, with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period). Permanent magnet quadrupoles (PMQs) are used as focusing elements in a FODO lattice scheme, which leaves space for steerers and diagnostics . In this paper beam dynamics studies and preliminary RF design are shown, including constraints in terms of quadrupole dimensions, total length, field stability, RF power, peak electric field.

THPB032

Beam Dynamics Design Aspects for a Proposed 800 MeV H⁻ ISIS Linac

linac, cavity, quadrupole, rfq

924

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H⁻ linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined with an emphasis on the beam dynamics design philosophy. The linac consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV.

THPB034

Status of the FAIR 70 MeV Proton Linac

proton, linac, rfq, cavity

927

L. Groening, W.A. Barth, R. Berezov, G. Clemente, P. Forck, R. Hollinger, A. Krämer, C. Mühle, J. Pfister, G. Schreiber, J. Trüller, W. Vinzenz, C. Will
GSI, Darmstadt, Germany
N. Chauvin, O. Delferrière, O. Tuske
CEA/IRFU, Gif-sur-Yvette, France
B. Koubek, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede
IAP, Frankfurt am Main, Germany
B. Launé, J. Lesrel
IPN, Orsay, France
C.S. Simon
CEA/DSM/IRFU, France

To provide the primary proton beam for the FAIR anti-proton research program, a 70 MeV, 70 mA linac is currently under design & construction at GSI. The nc machine comprises an ECR source, a 3 MeV RFQ, and a DTL based on CH-cavities. Up to 36 MeV pairs of rf-coupled cavities (CCH) are used. A prototype cavity has been built and is prepared for high power rf-testing. An overview of the status as well as on the perspectives of the project is given.

THPB036

The New Option for a Front End of Ion Linac

rfq, ion, proton, linac

933

A.D. Kovalenko
JINR, Dubna, Moscow Region, Russia
A. Kolomiets
ITEP, Moscow, Russia

The standard ion linac front-end consisting of RFQ, two tanks of accelerating IH-structures, MEBTs with matching and focusing elements is modified to achieve better performances. Special vane section that provides the same beam transformation as debuncher and quadrupole triplet is added within the RFQ tank, whereas superconducting focusing elements, solenoids, for example, are used between the IH - structure tanks. Test frond end was designed to provide the output beam energy up to 4 MeV/u for the particles with charge-to-mass ratio of 0.16 < q/m ≤ 1. Results of beam dynamics simulation are presented. Possible application of the considered scheme for the NICA facility at JINR (Dubna, Russia) is discussed.

FR1A04

In Flight Ion Separation using a Linac Chain

rfq, linac, ISAC, TRIUMF

1059

M. Marchetto, F. Ames, B. Davids, R.E. Laxdal, A.C. Morton
TRIUMF, Vancouver, Canada

The ISAC accelerator complex now can accelerate radioactive heavy ion beams to above the Coulomb Barrier. Recently an ECR type charge state booster has been added to allow the acceleration of radioactive beams with masses A>30. A characteristic of the ECR source is the efficient ionization of background species that can overwhelm the low intensity RIB beam. The long linac chain at ISAC can be used to provide some in flight separation both in time domain and in spatial domain analogous to fragment separators at in-flight fragmentation facilities. The talk will summarize the work done at TRIUMF to develop tools to aid in the filtration and diagnosis of beam purity in the post acceleration of charge bred beams. Marco Marchetto has been leading this effort.

Slides FR1A04 [24.174 MB]

FR2A01

Recovery of the J-PARC Linac from the Earthquake

linac, vacuum, ion, rfq

1069

K. Hasegawa
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Following the amazingly quick recovery from the disastrous earthquake in March 2011, and in the interests of promoting robust designs of linacs, it would be interesting to learn what the J-PARC team reckons are the key features of accelerator design and construction that lead to strong and reliable hardware.

Slides FR2A01 [3.928 MB]