LINAC2014 - List of Keywords (acceleration)

Paper	Title	Other Keywords	Page
MOPP005	High Power Electron Accelerator Programme at BARC	linac, electron, neutron, experiment	58
	K.C. Mittal, S. Acharya, R.I. Bakhtsingh, R. Barnwal, D. Bhattacharjee, S. Chandan, N. Chaudhary, R.B. Chavan, S.P. Dewangan, K.P. Dixit, S. Gade, L.M. Gantayet, S.R. Ghodke, S. Gond, D. Jayaprakash, M. Kumar, M.K. Kumar, H.K. Manjunatha, R.L. Mishra, J. Mondal, B. Nayak, S. Nayak, V.T. Nimje, S. Parashar, R. Patel, R.N. Rajan, P.C. Saroj, H.E. Sarukte, D.K. Sharma, V. Sharma, S.K. Srivasatava, N.T. Thakur, A.R. Tillu, R. Tiwari, H. Tyagi, A. Waghmare, V. Yadav BARC, Mumbai, India
	Bhabha Atomic Research Centre in India has taken up the indigenous design & development of high power electron accelerators for industrial, research and cargo-scanning applications. For this purpose, Electron Beam Centre (EBC) has been set up at Navi Mumbai, India. Pulsed RF Linacs, with on-axis coupled cavity configuration, include the 10 MeV Industrial RF linac, as well as 9 MeV linac and compact 6 MeV linac for cargo-scanning applications. Industrial DC accelerators include a 500 keV Cockroft-Walton machine and 3 MeV Dynamitron. Several radiation processing applications, such as material modification, food preservation, flue-gas treatment, etc. have been demonstrated using these accelerators. Cargo-scanning linacs have been successfully commissioned and are being characterized for the required x-ray output. A 30 MeV RF Linac, for research applications, such as shielding studies and n-ToF experiments, is being designed and developed. For ADS studies, a 100 MeV, 100 kW RF Linac system is proposed. This paper presents the details of the design of these accelerators, their development, current status and utilization for various applications.

MOPP021	XFEL Cryomodule Transportation: from the Assembly Laboratory in CEA-Saclay (France) to the Test-Hall in DESY-Hamburg (Germany)	cryomodule, damping, site, monitoring	98
	S. Barbanotti, K. Jensch, W. Maschmann, O. Sawlanski DESY, Hamburg, Germany
	The one hundred, 12 m long XFEL 1.3 GHz cryomodules are assembled at CEA Saclay (F) and have therefore to be transported, fully assembled, to the installation site in DESY Hamburg (D). Various studies and tests have been performed to assess and minimize the risk of damages during transportation; a new transport frame and a specialised company are being used for the series transportation. This paper resumes the studies performed, describes the final configuration adopted for the series transportation and the results obtained for the first XFEL modules.

MOPP030	CALIFES: A Multi-Purpose Electron Beam for Accelerator Technology Tests	electron, wakefield, quadrupole, laser	121
	J.L. Navarro Quirante, R. Corsini, W. Farabolini, D. Gamba, A. Grudiev, M.A. Khan, T. Lefèvre, S. Mazzoni, R. Pan, F. Peauger, F. Tecker, N. Vitoratou, K. Yaqub CERN, Geneva, Switzerland W. Farabolini, F. Peauger CEA/DSM/IRFU, France D. Gamba JAI, Oxford, United Kingdom M.A. Khan, K. Yaqub PINSTECH, Islamabad, Pakistan J. Ögren, R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden N. Vitoratou Thessaloniki University, Thessaloniki, Greece
	The Compact Linear Collider (CLIC) project aims to accelerate and collide electrons and positrons up to 3 TeV center-of-mass energy using a novel two-beam acceleration concept. To prove the feasibility of this technology the CLIC Test Facility CTF3 has been operated during the last years. CALIFES (Concept d’Accélérateur Linéaire pour Faisceau d’Electron Sonde) is an electron linac hosted in the CTF3 complex, which provides a flexible electron beam and the necessary equipment to probe both the two-beam acceleration concept and novel instrumentation to be used in the future CLIC collider. In this paper we describe the CALIFES Linac and its beam characteristics, present recent test results, outline its future program on two-beam module testing and finally discuss about possible future applications as a multi-purpose accelerator technology test facility.

MOPP112	Beam Dynamics of Multi Charge State Ions in RFQ Linac	ion, rfq, laser, ion-source	317
	Y. Fuwa, S. Ikeda, M. Kumaki RIKEN, Saitama, Japan Y. Fuwa, Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan T. Kanesue, M. Okamura BNL, Upton, Long Island, New York, USA
	Laser ion source with DPIS (Direct Plasma Injection Scheme) is a promising candidate for a pre-injector of the high-intensity accelerator. Eliminating LEBT (Low Energy Beam Transport) where the space charge effect is severe, DPIS provides high current ion beam from laser plasma at the entrance of a RFQ linac and ion beams are injected directly into the RFQ linac. However, the injected beam consists of multi charge state ions and their behavior in RFQ linac has not been well understood. In this research, we study the beam dynamics of multi charge state ions in a RFQ. Using the result of computer simulation, a set of 100MHz 4-rod RFQ vanes, which accelerates Al 12+ ion among various charge states of aluminum ions from 8.9 keV/u to 200 keV/u, is newly designed and fabricated to be tested with beams. The result of beam acceleration test using the vane will be reported.

MOPP123	Development Activities of Accelerator Instruments for SACLA	controls, cavity, klystron, laser	342
	Y. Otake, T. Asaka, T. Inagaki, C. Kondo, H. Maesaka, T. Ohshima, T. Sakurai, K. Togawa RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan H. Ego, S. Matsubara JASRI/SPring-8, Hyogo-ken, Japan
	The X-ray free-electron laser, SACLA, is constantly operated for user experiments aimed at new science. Experimental users demand further experimental abilities, such as many experimental chances by using multi-X-ray beam lines, much better repeatability of the experiment conditions and further intense high-energy X-rays. To equip SACLA with these abilities in the future, we have developed a 2pi /3 CG acceleration structure with an acceleration gradient of over 45 MV/m to adapt operation for generating the intense high-energy X-rays. A high-voltage power supply to charge the PFN of a modulator, a klystron and an acceleration structure were developed to adapt operation for 120 pps operation from the present 30 pps, since 120 pps is more suitable for beam distribution to the multi-beam lines. To meet the experimental repeatability realized by stable timing in a pump-probe experiment, an optical-fiber length control system to mitigate timing drift below 1 fs for 10 minutes was developed. Highly precise cavity temperature control system in an injector for below ±2mK was also realized. Performances of our developed instruments were experimentally tested to be sufficient for our demands.

MOPP127	Wakefield Effects of the Bypass Line in LCLS-II	dipole, wakefield, undulator, operation	355
	K.L.F. Bane, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Funding: Work supported by Department of Energy contract DE–AC02–76SF00515. In LCLS-II, after acceleration and compression and just before entering the undulator, the beam passes through roughly 2.5 km of 24.5 mm (radius) stainless steel pipe. The bunch that passes through the pipe is extremely short with an rms of 8 um for the nominal 100 pC case. Thus, even though the pipe has a large aperture, the wake that applies is the short-range resistive wall wakefield. It turns out that the wake supplies needed dechirping to the LCLS-II beam before it enters the undulator. The LCLS-II bunch distribution is approximately uniform, and therefore the wake induced voltage is characterized by a rather linear voltage chirp for short bunches. However for bunches longer than 25 um (300 pC at 1 kA) the wake starts to become nonlinear, effectively limiting the maximum charge with which the LCLS-II can operate. In this note we calculate the wake, discuss the confidence in the calculation, and investigate how to improve the induced chirp linearity and/or strength. Finally, we also study the strength and effects of the transverse (dipole) resistive wall wakefield.

MOPP128	Bridging the Gap Between Conventional RF Acceleration and Laser Driven Acceleration	electron, operation, experiment, cyclotron	358
	M.V. Fazio, V.A. Dolgashev, S.G. Tantawi SLAC, Menlo Park, California, USA
	For decades conventional RF accelerators have been built and operated with ever increasing capability through a few tens of gigahertz in frequency. More recent research takes advantage of the continuing development of high peak power short pulse lasers to drive accelerator structures at optical frequencies. This jump from RF to optical frequencies skips four orders of magnitude in wavelength. With recent experiments that demonstrate high gradients in metallic structures at millimeter wavelengths one is compelled to consider the viability of new approaches for acceleration in the millimeter-wave to terahertz regime. This paper will explore some of these possibilities.

MOPP139	Studies of Coherent Synchrotron Radiation in the Jefferson Lab FEL Driver with Implications for Bunch Compression	linac, emittance, simulation, FEL	388
	C. Tennant, D. Douglas, R. Li JLab, Newport News, Virginia, USA C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
	Funding: Work supported by the Office of Naval Research and the High Energy Laser Joint Technology. Jefferson Laboratory work is supported under U.S. DOE Contract No. DE-AC05-06OR23177. The Jefferson Laboratory IR FEL Driver provides an ideal test bed for studying a variety of beam dynamical effects. Recent studies focused on characterizing the impact of coherent synchrotron radiation (CSR) with the goal of benchmarking measurements with simulation. Following measurements to characterize the beam, we quantitatively characterized energy extraction via CSR by measuring beam position at a dispersed location as a function of bunch compression. In addition to operating with the beam on the rising part of the linac RF waveform, measurements were also made while accelerating on the falling part. For each, the full compression point was moved along the backleg of the machine and the response of the beam (distribution, extracted energy) measured. Initial results of start-to-end simulations using a 1D CSR algorithm show remarkably good agreement with measurements. A subsequent experiment established lasing with the beam accelerated on the falling side of the RF waveform in conjunction with positive momentum compaction (R56) to compress the bunch. The success of this experiment motivated the design of a modified CEBAF-style arc with control of CSR and microbunching effects.

TUPP028	Beam Tests at the CLIC Test Facility, CTF3	experiment, operation, emittance, linac	487
	R. Corsini, S. Döbert, W. Farabolini, D. Gamba, J.L. Navarro Quirante, T. Persson, P.K. Skowronski, F. Tecker CERN, Geneva, Switzerland W. Farabolini CEA/DSM/IRFU, France D. Gamba JAI, Oxford, United Kingdom
	The CLIC Test Facility CTF3 has been built at CERN by the Compact Linear Collider (CLIC) International Collaboration, in order to prove the main feasibility issues of the two-beam acceleration technology on which the collider is based. After the successful completion of its initial task, CTF3 is continuing its experimental program in order to give further indications on cost and performance issues, to act as a test bed for the CLIC technology, and to conduct beam experiments aimed at mitigating technological risks. In this paper we discuss the status of the ongoing experiments and present the more recent results, including improvements in beam quality and stability.

TUPP033	Effect of Beam-Loading on the Breakdown Rate of High Gradient Accelerating Structures	klystron, beam-loading, experiment, linac	499
	J.L. Navarro Quirante, R. Corsini, A. Degiovanni, S. Döbert, A. Grudiev, O. Kononenko, G. McMonagle, S.F. Rey, A. Solodko, I. Syratchev, F. Tecker, L. Timeo, B.J. Woolley, X.W. Wu, W. Wuensch CERN, Geneva, Switzerland O. Kononenko SLAC, Menlo Park, California, USA A. Solodko JINR, Dubna, Moscow Region, Russia J. Tagg National Instruments Switzerland, Ennetbaden, Switzerland B.J. Woolley Cockcroft Institute, Lancaster University, Lancaster, United Kingdom X.W. Wu TUB, Beijing, People's Republic of China
	The Compact Linear Collider (CLIC) is a study for a future room temperature electron-positron collider with a maximum center-of-mass energy of 3 TeV. To efficiently achieve such high energy, the project relies on a novel two beam acceleration concept and on high-gradient accelerating structures working at 100 MV/m. In order to meet the luminosity requirements, the break-down rate in these high-field structures has to be kept below 10 per billion. Such gradients and breakdown rates have been demonstrated by high-power RF testing several 12 GHz structures. However, the presence of beam-loading modifies the field distribution for the structure, such that a higher input power is needed in order to achieve the same accelerating gradient as the unloaded case. The potential impact on the break-down rate was never measured before. In this paper we present an experiment located at the CLIC Test Facility CTF3 recently proposed in order to quantify this effect, layout and hardware status, and discuss its first results.
	Slides TUPP033 [1.970 MB]
	Poster TUPP033 [2.355 MB]

TUPP045	Beam Physics Challenge in FRIB Driver Linac	linac, ion, proton, focusing	532
	Y. Yamazaki, N.K. Bultman, A. Facco, Z.Q. He, M. Ikegami, M.J. Johnson, S.M. Lidia, F. Marti, G. Pozdeyev, K. Saito, J. Wei, X. Wu, Y. Zhang, Q. Zhao FRIB, East Lansing, Michigan, USA
	Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The Facility for Rare Isotope Beams driver linac provides CW beams of all the stable ions (from protons to uranium) with a beam power of 400 kW and a minimum beam energy of 200 MeV/u in order to produce a wide variety of rare isotopes, mainly for nuclear physics study. The low beam emittances, both transverse and longitudinal, are key performance requirements, together with beam stability. These are required for efficiently separating one isotope from another, the reason for choosing this linac configuration. Multi-charge states (five charge states for the uranium case) are accelerated for maximizing the beam current, while keeping the low emittances. The efficient acceleration of high beam currents from 0.5 MeV/u through the superconducting linac is, needless to say, one of the biggest challenges. The beam power is more than 200 times higher than existing similar SC heavy ion linac. In particular, the SC cavities are difficult to protect from heavy ion beam damage, which can be 30 times larger locally than a proton beam with the same beam power. Other challenges peculiar to the FRIB linac will be presented, together with the solutions.

TUPP072	Studies on Wake Field in Annular Coupled Structure	wakefield, impedance, cavity, linac	593
	Y. Liu, T. Maruta KEK/JAEA, Ibaraki-Ken, Japan K. Futatsukawa KEK, Ibaraki, Japan A. Miura JAEA/J-PARC, Tokai-mura, Japan
	LINAC injector of J-PARC (Japan Proton Accelerator Research Complex) was recently successfully upgraded from 181 MeV to 400 MeV, applying a type of coupled cavity linac (CCL) structure ACS (Annular Coupled Structure). It was warmly discussed since very beginning on the wake field in the ACS cavities, where there are CCL modes with the same number as that of cells within ~50 MHz, possibly resonating with high intensity proton/H⁻ beams. One of the most important effects from the wake field is the influence on the ACS phase scan. Analytical and simulation studies, as well as the countermeasures were prepared before the energy upgrade. Fortunately we found that detuning of the ACS was unnecessary, which helped to save much work in the commissioning. In addition we got chance to make experiment studies. It was also discussed why the wake field is not so serious as we expected at the very beginning.

TUPP094	Recent Progress of Beam Commissioning at J-PARC Linac	linac, operation, DTL, cavity	646
	T. Maruta J-PARC, KEK & JAEA, Ibaraki-ken, Japan K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan M. Ikegami FRIB, East Lansing, Michigan, USA Y. Liu KEK/JAEA, Ibaraki-Ken, Japan A. Miura, H. Sako JAEA/J-PARC, Tokai-mura, Japan
	We installed Annular-type Coupled Structure (ACS) linac in year 2013 in present linac downstream to extend the beam energy from 181 to 400 MeV. The beam commissioning had been conducted for one month in last December to January, and then we successfully extract 400 MeV beam. Whereas, we stably operate the linac at peak current of 15 mA, which is equivalent to 300 kW at the extraction of 3 GeV RCS, we observe unexpected residual radiations in ACS section. In this presentation, we review the recent progress in beam commissioning and beam loss study.

TUPP109	Cryogenic Testing of High-Velocity Spoke Cavities	cavity, cryogenics, proton, linac	677
	C.S. Hopper, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA J.R. Delayen, H. Park JLab, Newport News, Virginia, USA
	Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, β0 = 0.82 single-spoke cavity and a 500 MHz, β0 = 1 double-spoke cavity.

TUPP121	Limitations for Acceleration of Intermediate Mass Particles with Traveling Wave Structure	operation, electron, accelerating-gradient, linac	705
	V.V. Paramonov RAS/INR, Moscow, Russia
	The Disk Loaded Waveguide (DLW) is the mostly used high frequency structure for acceleration of lightweight particles – electrons in the high energy range. DLW parameters are considered for the lower frequency range and lower particle velocity. Physical and technical restrictions for DLW application for the low particles velocity are analyzed. Basing on particularities of acceleration with traveling wave, deep optimization of DLW cells dimensions, the choice of optimal operating phase advance for each DLW section and combination of forward and backward wave modes, it looks possible to create the simple, cost effective acceleration system for intermediate particles acceleration in the moderate velocity range, in some parameters overcoming accelerating system with RF cavities in the standing wave mode.

TUPP133	Optimization of the RF Cavity of the Medical Purpose Electron Linac by Using Genetic Algorithm	cavity, electron, impedance, linac	726
	S. Shin, J.-S. Chai SKKU, Suwon, Republic of Korea
	A compact electron linear accelerator for the medical application has been developing at Sungkyunkwan University. Due to this electron linac is attached on the robot arm or gantry, it should be compact enough to be held by the structure. An X-band technology has been used to meet the requirements for the compact linac. Because the particle accelerator is complex and sensitive machine to design it takes a lot of time to get a good performance accelerator. In this research, a special technique named single-objective genetic algorithm for the optimization process has been applied to achieve a better RF cavity design by changing various geometric parameters.

THIOA01	Cost Optimized Design of High Power Linacs	linac, cavity, neutron, emittance	785
	M. Eshraqi ESS, Lund, Sweden
	The research accelerators are growing in energy and power which translates to an increase in their cost, and also size if the conventional acceleration techniques are used. On the other hand, handling megawatts of power requires a design that is robust, respects the known criteria in beam physics to avoid losses in the order of less than one part in million. Traditionally cost increases with power and quality of the accelerator and beam. In this paper, using the ESS linac as an example, this tradition is challenged and ways to reduce the cost while neither quality nor power is compromised are presented.
	Slides THIOA01 [8.363 MB]

THPP035	Deceleration Measurements of an Electron Beam in the CLIC Test Facility 3	electron, lattice, quadrupole, linear-collider	920
	R.L. Lillestøl, S. Döbert CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The Test Beam Line at the CLIC Test Facility 3 at CERN is a proof-of-principle of the future CLIC decelerators, which will extract a large amount of beam energy for acceleration of the main CLIC beams. The current beamline consists of a FODO lattice with 13 Power Extraction and Transfer Structures (PETS). We discuss beam deceleration measurements of up to 37 %, taking into account effects from the bunch length and the bunch phase. The 12 GHz phase is reproduced based on measurements in a PETS with an uncombined beam. The spectrometer measurements are also compared to predictions based on the beam current and on the produced rf power in the PETS, as well as particle tracking simulations with the Placet code.

THPP065	Acceleration of Intense Flat Beams in Periodic Lattices	emittance, DTL, focusing, space-charge	1001
	L. Groening, C. Xiao GSI, Darmstadt, Germany I. Hofmann TEMF, TU Darmstadt, Darmstadt, Germany
	Recently a scheme for creation of flat ion beams from linacs has been proposed to increase the efficiency of multi-turn-injection. The proof of principle experiment shall be performed at GSI in Summer 2014. Since the scheme requires charge stripping, it may be necessary to perform the round-to-flat transformation prior to acceleration to the final energy of the linac. This requires preservation of the beam flatness during acceleration along the drift tube linac. This contribution is on simulations of acceleration of flat beams subject to considerable space charge tune depression. It is shown that the flatness can be preserved if the transverse tunes are properly chosen and if mis-match along inter-tank sections is minimized along the DTL.

THPP075	Development of Superconducting Spoke Cavity for Electron Accelerators	cavity, simulation, electron, multipactoring	1030
	T. Kubo, T. Saeki KEK, Ibaraki, Japan E. Cenni, H. Fujisawa, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan R. Hajima, M. Sawamura JAEA, Ibaraki-ken, Japan
	Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. We have launched a development program of a superconducting spoke cavity for electron acceleration, in order to realize a compact industrial-use X-ray source with the laser-Compton scattering. Efforts for optimizing a cavity design by the electromagnetic field simulation, tracking of multipactor electrons and mechanical property calculations have been continued so far. The optimization processes reached the final stage, and studies toward fabrication processes started. In this presentation, we will show results and processes of the optimization. Attempts to fabricate the spoke cavity, which have just begun, will also be presented.

THPP091	Installation and Performance Check of Beam Monitors for Energy Upgraded J-PARC Linac	linac, operation, quadrupole, cavity	1059
	A. Miura, K. Hasegawa, H. Oguri, N. Ouchi JAEA/J-PARC, Tokai-mura, Japan M. Ikegami FRIB, East Lansing, Michigan, USA Y. Liu KEK/JAEA, Ibaraki-Ken, Japan T. Maruta J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Miyao KEK, Ibaraki, Japan
	An energy upgrade project has started to achieve the design beam power of 1 MW at the exit of the downstream synchrotron in the J-PARC Linac since 2009. In the upgraded project, a beam energy in the Linac has increased from present 181 MeV to 400 MeV using the additional 21 annular-ring coupled structure (ACS) cavities. The new beam monitors as the beam current monitors, the phase monitors, the beam position monitors, the transverse profile monitors (wire scanner monitors) and the longitudinal profile monitors (bunch shape monitors) for the part where the ACS cavities were installed were designed, fabricated and calibrated. Till the end of November, 2013, all beam monitors were completed to be installed. From the middle of December, we started the beam commissioning to achieve the beam energy as 400 MeV, as well as to confirm the beam monitor functioning. We achieved the 400 MeV beam acceleration at the middle of January, 2014 using newly installed beam monitors. This paper describes the beam monitor installation, calibration and the beam commissioning results of beam monitor functioning.

THPP092	Development of Slow Neutron Accelerator for Rebunching Pulsed Neutrons	neutron, experiment, resonance, impedance	1062
	S. Imajo Kyoto University, Kyoto, Japan Y. Fuwa, Y. Iwashita, R. Kitahara Kyoto ICR, Uji, Kyoto, Japan T. Ino KEK, Ibaraki, Japan M. Kitaguchi, H.M. Shimizu Nagoya University, Nagoya, Japan K. Mishima ICEPP, Tokyo, Japan
	Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF and gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons, however, the pulsed neutrons with several velocities are diffused in guide tubes under long beam intervals. It is necessary to focus and rebunch UCN temporally upon the bottle by controlling their velocities in nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured characteristics, the experimental setup and the obtained results at J-PARC will be described.

THPP118	Design of a New Superconducting Linac for the RIBF Upgrade	linac, cyclotron, ion, emittance	1127
	K. Yamada, O. Kamigaito, N. Sakamoto, K. Suda RIKEN Nishina Center, Wako, Japan
	An upgrade plan for the RIKEN RI-Beam Factory[1] is under discussion, the objective being to significantly increase the uranium beam intensity. In the upgrade plan, the existing ring cyclotron called RRC[2] will be replaced by a new linac, mainly consisting of superconducting (SC) cavities. The new linac is designed to accelerate heavy ions with a mass-to-charge ratio of ~7, such as 238U³⁵⁺, up to an energy of 11 MeV/u in the cw mode. The present injector linac, RILAC2[3], will be used for the low-energy end, and a short room-temperature (RT) section will be added to RILAC2, which will boost the beam energy up to 1.4 MeV/u. The succeeding SC section consists of 14 cryomodules, each of which contains four quater-wavelength resonators (QWRs) with two gaps operated at 73 MHz. A RT quadrupole doublet is placed in each gap between the cryomodules. The modular configuration of the SC section was optimized based on the first-order approximation for the transverse and longitudinal motions. The designs of SC QWR were carried out using CST Microwave Studio 2013. Further study is under way on the SC QWR including the mechanical considerations, and we also start a design of cryostats. [1] Y. Yano, Nucl. Instr. Meth. B 261, 1009 (2007). [2] Y. Yano, Proc. 13th Int. Cyclo. Conf., 102 (1992). [3] K. Yamada et al., Proc. of IPAC'12, TUOBA02, 1071 (2012).

Paper

Title

Other Keywords

Page

MOPP005

High Power Electron Accelerator Programme at BARC

linac, electron, neutron, experiment

58

K.C. Mittal, S. Acharya, R.I. Bakhtsingh, R. Barnwal, D. Bhattacharjee, S. Chandan, N. Chaudhary, R.B. Chavan, S.P. Dewangan, K.P. Dixit, S. Gade, L.M. Gantayet, S.R. Ghodke, S. Gond, D. Jayaprakash, M. Kumar, M.K. Kumar, H.K. Manjunatha, R.L. Mishra, J. Mondal, B. Nayak, S. Nayak, V.T. Nimje, S. Parashar, R. Patel, R.N. Rajan, P.C. Saroj, H.E. Sarukte, D.K. Sharma, V. Sharma, S.K. Srivasatava, N.T. Thakur, A.R. Tillu, R. Tiwari, H. Tyagi, A. Waghmare, V. Yadav
BARC, Mumbai, India

Bhabha Atomic Research Centre in India has taken up the indigenous design & development of high power electron accelerators for industrial, research and cargo-scanning applications. For this purpose, Electron Beam Centre (EBC) has been set up at Navi Mumbai, India. Pulsed RF Linacs, with on-axis coupled cavity configuration, include the 10 MeV Industrial RF linac, as well as 9 MeV linac and compact 6 MeV linac for cargo-scanning applications. Industrial DC accelerators include a 500 keV Cockroft-Walton machine and 3 MeV Dynamitron. Several radiation processing applications, such as material modification, food preservation, flue-gas treatment, etc. have been demonstrated using these accelerators. Cargo-scanning linacs have been successfully commissioned and are being characterized for the required x-ray output. A 30 MeV RF Linac, for research applications, such as shielding studies and n-ToF experiments, is being designed and developed. For ADS studies, a 100 MeV, 100 kW RF Linac system is proposed. This paper presents the details of the design of these accelerators, their development, current status and utilization for various applications.

MOPP021

XFEL Cryomodule Transportation: from the Assembly Laboratory in CEA-Saclay (France) to the Test-Hall in DESY-Hamburg (Germany)

cryomodule, damping, site, monitoring

98

S. Barbanotti, K. Jensch, W. Maschmann, O. Sawlanski
DESY, Hamburg, Germany

The one hundred, 12 m long XFEL 1.3 GHz cryomodules are assembled at CEA Saclay (F) and have therefore to be transported, fully assembled, to the installation site in DESY Hamburg (D). Various studies and tests have been performed to assess and minimize the risk of damages during transportation; a new transport frame and a specialised company are being used for the series transportation. This paper resumes the studies performed, describes the final configuration adopted for the series transportation and the results obtained for the first XFEL modules.

MOPP030

CALIFES: A Multi-Purpose Electron Beam for Accelerator Technology Tests

electron, wakefield, quadrupole, laser

121

J.L. Navarro Quirante, R. Corsini, W. Farabolini, D. Gamba, A. Grudiev, M.A. Khan, T. Lefèvre, S. Mazzoni, R. Pan, F. Peauger, F. Tecker, N. Vitoratou, K. Yaqub
CERN, Geneva, Switzerland
W. Farabolini, F. Peauger
CEA/DSM/IRFU, France
D. Gamba
JAI, Oxford, United Kingdom
M.A. Khan, K. Yaqub
PINSTECH, Islamabad, Pakistan
J. Ögren, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
N. Vitoratou
Thessaloniki University, Thessaloniki, Greece

The Compact Linear Collider (CLIC) project aims to accelerate and collide electrons and positrons up to 3 TeV center-of-mass energy using a novel two-beam acceleration concept. To prove the feasibility of this technology the CLIC Test Facility CTF3 has been operated during the last years. CALIFES (Concept d’Accélérateur Linéaire pour Faisceau d’Electron Sonde) is an electron linac hosted in the CTF3 complex, which provides a flexible electron beam and the necessary equipment to probe both the two-beam acceleration concept and novel instrumentation to be used in the future CLIC collider. In this paper we describe the CALIFES Linac and its beam characteristics, present recent test results, outline its future program on two-beam module testing and finally discuss about possible future applications as a multi-purpose accelerator technology test facility.

MOPP112

Beam Dynamics of Multi Charge State Ions in RFQ Linac

ion, rfq, laser, ion-source

317

Y. Fuwa, S. Ikeda, M. Kumaki
RIKEN, Saitama, Japan
Y. Fuwa, Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
T. Kanesue, M. Okamura
BNL, Upton, Long Island, New York, USA

Laser ion source with DPIS (Direct Plasma Injection Scheme) is a promising candidate for a pre-injector of the high-intensity accelerator. Eliminating LEBT (Low Energy Beam Transport) where the space charge effect is severe, DPIS provides high current ion beam from laser plasma at the entrance of a RFQ linac and ion beams are injected directly into the RFQ linac. However, the injected beam consists of multi charge state ions and their behavior in RFQ linac has not been well understood. In this research, we study the beam dynamics of multi charge state ions in a RFQ. Using the result of computer simulation, a set of 100MHz 4-rod RFQ vanes, which accelerates Al 12+ ion among various charge states of aluminum ions from 8.9 keV/u to 200 keV/u, is newly designed and fabricated to be tested with beams. The result of beam acceleration test using the vane will be reported.

MOPP123

Development Activities of Accelerator Instruments for SACLA

controls, cavity, klystron, laser

342

Y. Otake, T. Asaka, T. Inagaki, C. Kondo, H. Maesaka, T. Ohshima, T. Sakurai, K. Togawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
H. Ego, S. Matsubara
JASRI/SPring-8, Hyogo-ken, Japan

The X-ray free-electron laser, SACLA, is constantly operated for user experiments aimed at new science. Experimental users demand further experimental abilities, such as many experimental chances by using multi-X-ray beam lines, much better repeatability of the experiment conditions and further intense high-energy X-rays. To equip SACLA with these abilities in the future, we have developed a 2pi /3 CG acceleration structure with an acceleration gradient of over 45 MV/m to adapt operation for generating the intense high-energy X-rays. A high-voltage power supply to charge the PFN of a modulator, a klystron and an acceleration structure were developed to adapt operation for 120 pps operation from the present 30 pps, since 120 pps is more suitable for beam distribution to the multi-beam lines. To meet the experimental repeatability realized by stable timing in a pump-probe experiment, an optical-fiber length control system to mitigate timing drift below 1 fs for 10 minutes was developed. Highly precise cavity temperature control system in an injector for below ±2mK was also realized. Performances of our developed instruments were experimentally tested to be sufficient for our demands.

MOPP127

Wakefield Effects of the Bypass Line in LCLS-II

dipole, wakefield, undulator, operation

355

K.L.F. Bane, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.
In LCLS-II, after acceleration and compression and just before entering the undulator, the beam passes through roughly 2.5 km of 24.5 mm (radius) stainless steel pipe. The bunch that passes through the pipe is extremely short with an rms of 8 um for the nominal 100 pC case. Thus, even though the pipe has a large aperture, the wake that applies is the short-range resistive wall wakefield. It turns out that the wake supplies needed dechirping to the LCLS-II beam before it enters the undulator. The LCLS-II bunch distribution is approximately uniform, and therefore the wake induced voltage is characterized by a rather linear voltage chirp for short bunches. However for bunches longer than 25 um (300 pC at 1 kA) the wake starts to become nonlinear, effectively limiting the maximum charge with which the LCLS-II can operate. In this note we calculate the wake, discuss the confidence in the calculation, and investigate how to improve the induced chirp linearity and/or strength. Finally, we also study the strength and effects of the transverse (dipole) resistive wall wakefield.

MOPP128

Bridging the Gap Between Conventional RF Acceleration and Laser Driven Acceleration

electron, operation, experiment, cyclotron

358

M.V. Fazio, V.A. Dolgashev, S.G. Tantawi
SLAC, Menlo Park, California, USA

For decades conventional RF accelerators have been built and operated with ever increasing capability through a few tens of gigahertz in frequency. More recent research takes advantage of the continuing development of high peak power short pulse lasers to drive accelerator structures at optical frequencies. This jump from RF to optical frequencies skips four orders of magnitude in wavelength. With recent experiments that demonstrate high gradients in metallic structures at millimeter wavelengths one is compelled to consider the viability of new approaches for acceleration in the millimeter-wave to terahertz regime. This paper will explore some of these possibilities.

MOPP139

Studies of Coherent Synchrotron Radiation in the Jefferson Lab FEL Driver with Implications for Bunch Compression

linac, emittance, simulation, FEL

388

C. Tennant, D. Douglas, R. Li
JLab, Newport News, Virginia, USA
C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

Funding: Work supported by the Office of Naval Research and the High Energy Laser Joint Technology. Jefferson Laboratory work is supported under U.S. DOE Contract No. DE-AC05-06OR23177.
The Jefferson Laboratory IR FEL Driver provides an ideal test bed for studying a variety of beam dynamical effects. Recent studies focused on characterizing the impact of coherent synchrotron radiation (CSR) with the goal of benchmarking measurements with simulation. Following measurements to characterize the beam, we quantitatively characterized energy extraction via CSR by measuring beam position at a dispersed location as a function of bunch compression. In addition to operating with the beam on the rising part of the linac RF waveform, measurements were also made while accelerating on the falling part. For each, the full compression point was moved along the backleg of the machine and the response of the beam (distribution, extracted energy) measured. Initial results of start-to-end simulations using a 1D CSR algorithm show remarkably good agreement with measurements. A subsequent experiment established lasing with the beam accelerated on the falling side of the RF waveform in conjunction with positive momentum compaction (R56) to compress the bunch. The success of this experiment motivated the design of a modified CEBAF-style arc with control of CSR and microbunching effects.

TUPP028

Beam Tests at the CLIC Test Facility, CTF3

experiment, operation, emittance, linac

487

R. Corsini, S. Döbert, W. Farabolini, D. Gamba, J.L. Navarro Quirante, T. Persson, P.K. Skowronski, F. Tecker
CERN, Geneva, Switzerland
W. Farabolini
CEA/DSM/IRFU, France
D. Gamba
JAI, Oxford, United Kingdom

The CLIC Test Facility CTF3 has been built at CERN by the Compact Linear Collider (CLIC) International Collaboration, in order to prove the main feasibility issues of the two-beam acceleration technology on which the collider is based. After the successful completion of its initial task, CTF3 is continuing its experimental program in order to give further indications on cost and performance issues, to act as a test bed for the CLIC technology, and to conduct beam experiments aimed at mitigating technological risks. In this paper we discuss the status of the ongoing experiments and present the more recent results, including improvements in beam quality and stability.

TUPP033

Effect of Beam-Loading on the Breakdown Rate of High Gradient Accelerating Structures

klystron, beam-loading, experiment, linac

499

J.L. Navarro Quirante, R. Corsini, A. Degiovanni, S. Döbert, A. Grudiev, O. Kononenko, G. McMonagle, S.F. Rey, A. Solodko, I. Syratchev, F. Tecker, L. Timeo, B.J. Woolley, X.W. Wu, W. Wuensch
CERN, Geneva, Switzerland
O. Kononenko
SLAC, Menlo Park, California, USA
A. Solodko
JINR, Dubna, Moscow Region, Russia
J. Tagg
National Instruments Switzerland, Ennetbaden, Switzerland
B.J. Woolley
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
X.W. Wu
TUB, Beijing, People's Republic of China

The Compact Linear Collider (CLIC) is a study for a future room temperature electron-positron collider with a maximum center-of-mass energy of 3 TeV. To efficiently achieve such high energy, the project relies on a novel two beam acceleration concept and on high-gradient accelerating structures working at 100 MV/m. In order to meet the luminosity requirements, the break-down rate in these high-field structures has to be kept below 10 per billion. Such gradients and breakdown rates have been demonstrated by high-power RF testing several 12 GHz structures. However, the presence of beam-loading modifies the field distribution for the structure, such that a higher input power is needed in order to achieve the same accelerating gradient as the unloaded case. The potential impact on the break-down rate was never measured before. In this paper we present an experiment located at the CLIC Test Facility CTF3 recently proposed in order to quantify this effect, layout and hardware status, and discuss its first results.

Slides TUPP033 [1.970 MB]

Poster TUPP033 [2.355 MB]

TUPP045

Beam Physics Challenge in FRIB Driver Linac

linac, ion, proton, focusing

532

Y. Yamazaki, N.K. Bultman, A. Facco, Z.Q. He, M. Ikegami, M.J. Johnson, S.M. Lidia, F. Marti, G. Pozdeyev, K. Saito, J. Wei, X. Wu, Y. Zhang, Q. Zhao
FRIB, East Lansing, Michigan, USA

Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The Facility for Rare Isotope Beams driver linac provides CW beams of all the stable ions (from protons to uranium) with a beam power of 400 kW and a minimum beam energy of 200 MeV/u in order to produce a wide variety of rare isotopes, mainly for nuclear physics study. The low beam emittances, both transverse and longitudinal, are key performance requirements, together with beam stability. These are required for efficiently separating one isotope from another, the reason for choosing this linac configuration. Multi-charge states (five charge states for the uranium case) are accelerated for maximizing the beam current, while keeping the low emittances. The efficient acceleration of high beam currents from 0.5 MeV/u through the superconducting linac is, needless to say, one of the biggest challenges. The beam power is more than 200 times higher than existing similar SC heavy ion linac. In particular, the SC cavities are difficult to protect from heavy ion beam damage, which can be 30 times larger locally than a proton beam with the same beam power. Other challenges peculiar to the FRIB linac will be presented, together with the solutions.

TUPP072

Studies on Wake Field in Annular Coupled Structure

wakefield, impedance, cavity, linac

593

Y. Liu, T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
K. Futatsukawa
KEK, Ibaraki, Japan
A. Miura
JAEA/J-PARC, Tokai-mura, Japan

LINAC injector of J-PARC (Japan Proton Accelerator Research Complex) was recently successfully upgraded from 181 MeV to 400 MeV, applying a type of coupled cavity linac (CCL) structure ACS (Annular Coupled Structure). It was warmly discussed since very beginning on the wake field in the ACS cavities, where there are CCL modes with the same number as that of cells within ~50 MHz, possibly resonating with high intensity proton/H⁻ beams. One of the most important effects from the wake field is the influence on the ACS phase scan. Analytical and simulation studies, as well as the countermeasures were prepared before the energy upgrade. Fortunately we found that detuning of the ACS was unnecessary, which helped to save much work in the commissioning. In addition we got chance to make experiment studies. It was also discussed why the wake field is not so serious as we expected at the very beginning.

TUPP094

Recent Progress of Beam Commissioning at J-PARC Linac

linac, operation, DTL, cavity

646

T. Maruta
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
M. Ikegami
FRIB, East Lansing, Michigan, USA
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
A. Miura, H. Sako
JAEA/J-PARC, Tokai-mura, Japan

We installed Annular-type Coupled Structure (ACS) linac in year 2013 in present linac downstream to extend the beam energy from 181 to 400 MeV. The beam commissioning had been conducted for one month in last December to January, and then we successfully extract 400 MeV beam. Whereas, we stably operate the linac at peak current of 15 mA, which is equivalent to 300 kW at the extraction of 3 GeV RCS, we observe unexpected residual radiations in ACS section. In this presentation, we review the recent progress in beam commissioning and beam loss study.

TUPP109

Cryogenic Testing of High-Velocity Spoke Cavities

cavity, cryogenics, proton, linac

677

C.S. Hopper, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
J.R. Delayen, H. Park
JLab, Newport News, Virginia, USA

Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, β0 = 0.82 single-spoke cavity and a 500 MHz, β0 = 1 double-spoke cavity.

TUPP121

Limitations for Acceleration of Intermediate Mass Particles with Traveling Wave Structure

operation, electron, accelerating-gradient, linac

705

V.V. Paramonov
RAS/INR, Moscow, Russia

The Disk Loaded Waveguide (DLW) is the mostly used high frequency structure for acceleration of lightweight particles – electrons in the high energy range. DLW parameters are considered for the lower frequency range and lower particle velocity. Physical and technical restrictions for DLW application for the low particles velocity are analyzed. Basing on particularities of acceleration with traveling wave, deep optimization of DLW cells dimensions, the choice of optimal operating phase advance for each DLW section and combination of forward and backward wave modes, it looks possible to create the simple, cost effective acceleration system for intermediate particles acceleration in the moderate velocity range, in some parameters overcoming accelerating system with RF cavities in the standing wave mode.

TUPP133

Optimization of the RF Cavity of the Medical Purpose Electron Linac by Using Genetic Algorithm

cavity, electron, impedance, linac

726

S. Shin, J.-S. Chai
SKKU, Suwon, Republic of Korea

A compact electron linear accelerator for the medical application has been developing at Sungkyunkwan University. Due to this electron linac is attached on the robot arm or gantry, it should be compact enough to be held by the structure. An X-band technology has been used to meet the requirements for the compact linac. Because the particle accelerator is complex and sensitive machine to design it takes a lot of time to get a good performance accelerator. In this research, a special technique named single-objective genetic algorithm for the optimization process has been applied to achieve a better RF cavity design by changing various geometric parameters.

THIOA01

Cost Optimized Design of High Power Linacs

linac, cavity, neutron, emittance

785

M. Eshraqi
ESS, Lund, Sweden

The research accelerators are growing in energy and power which translates to an increase in their cost, and also size if the conventional acceleration techniques are used. On the other hand, handling megawatts of power requires a design that is robust, respects the known criteria in beam physics to avoid losses in the order of less than one part in million. Traditionally cost increases with power and quality of the accelerator and beam. In this paper, using the ESS linac as an example, this tradition is challenged and ways to reduce the cost while neither quality nor power is compromised are presented.

Slides THIOA01 [8.363 MB]

THPP035

Deceleration Measurements of an Electron Beam in the CLIC Test Facility 3

electron, lattice, quadrupole, linear-collider

920

R.L. Lillestøl, S. Döbert
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The Test Beam Line at the CLIC Test Facility 3 at CERN is a proof-of-principle of the future CLIC decelerators, which will extract a large amount of beam energy for acceleration of the main CLIC beams. The current beamline consists of a FODO lattice with 13 Power Extraction and Transfer Structures (PETS). We discuss beam deceleration measurements of up to 37 %, taking into account effects from the bunch length and the bunch phase. The 12 GHz phase is reproduced based on measurements in a PETS with an uncombined beam. The spectrometer measurements are also compared to predictions based on the beam current and on the produced rf power in the PETS, as well as particle tracking simulations with the Placet code.

THPP065

Acceleration of Intense Flat Beams in Periodic Lattices

emittance, DTL, focusing, space-charge

1001

L. Groening, C. Xiao
GSI, Darmstadt, Germany
I. Hofmann
TEMF, TU Darmstadt, Darmstadt, Germany

Recently a scheme for creation of flat ion beams from linacs has been proposed to increase the efficiency of multi-turn-injection. The proof of principle experiment shall be performed at GSI in Summer 2014. Since the scheme requires charge stripping, it may be necessary to perform the round-to-flat transformation prior to acceleration to the final energy of the linac. This requires preservation of the beam flatness during acceleration along the drift tube linac. This contribution is on simulations of acceleration of flat beams subject to considerable space charge tune depression. It is shown that the flatness can be preserved if the transverse tunes are properly chosen and if mis-match along inter-tank sections is minimized along the DTL.

THPP075

Development of Superconducting Spoke Cavity for Electron Accelerators

cavity, simulation, electron, multipactoring

1030

T. Kubo, T. Saeki
KEK, Ibaraki, Japan
E. Cenni, H. Fujisawa, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
R. Hajima, M. Sawamura
JAEA, Ibaraki-ken, Japan

Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have launched a development program of a superconducting spoke cavity for electron acceleration, in order to realize a compact industrial-use X-ray source with the laser-Compton scattering. Efforts for optimizing a cavity design by the electromagnetic field simulation, tracking of multipactor electrons and mechanical property calculations have been continued so far. The optimization processes reached the final stage, and studies toward fabrication processes started. In this presentation, we will show results and processes of the optimization. Attempts to fabricate the spoke cavity, which have just begun, will also be presented.

THPP091

Installation and Performance Check of Beam Monitors for Energy Upgraded J-PARC Linac

linac, operation, quadrupole, cavity

1059

A. Miura, K. Hasegawa, H. Oguri, N. Ouchi
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
FRIB, East Lansing, Michigan, USA
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
T. Maruta
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Miyao
KEK, Ibaraki, Japan

An energy upgrade project has started to achieve the design beam power of 1 MW at the exit of the downstream synchrotron in the J-PARC Linac since 2009. In the upgraded project, a beam energy in the Linac has increased from present 181 MeV to 400 MeV using the additional 21 annular-ring coupled structure (ACS) cavities. The new beam monitors as the beam current monitors, the phase monitors, the beam position monitors, the transverse profile monitors (wire scanner monitors) and the longitudinal profile monitors (bunch shape monitors) for the part where the ACS cavities were installed were designed, fabricated and calibrated. Till the end of November, 2013, all beam monitors were completed to be installed. From the middle of December, we started the beam commissioning to achieve the beam energy as 400 MeV, as well as to confirm the beam monitor functioning. We achieved the 400 MeV beam acceleration at the middle of January, 2014 using newly installed beam monitors. This paper describes the beam monitor installation, calibration and the beam commissioning results of beam monitor functioning.

THPP092

Development of Slow Neutron Accelerator for Rebunching Pulsed Neutrons

neutron, experiment, resonance, impedance

1062

S. Imajo
Kyoto University, Kyoto, Japan
Y. Fuwa, Y. Iwashita, R. Kitahara
Kyoto ICR, Uji, Kyoto, Japan
T. Ino
KEK, Ibaraki, Japan
M. Kitaguchi, H.M. Shimizu
Nagoya University, Nagoya, Japan
K. Mishima
ICEPP, Tokyo, Japan

Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF and gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons, however, the pulsed neutrons with several velocities are diffused in guide tubes under long beam intervals. It is necessary to focus and rebunch UCN temporally upon the bottle by controlling their velocities in nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured characteristics, the experimental setup and the obtained results at J-PARC will be described.

THPP118

Design of a New Superconducting Linac for the RIBF Upgrade

linac, cyclotron, ion, emittance

1127

K. Yamada, O. Kamigaito, N. Sakamoto, K. Suda
RIKEN Nishina Center, Wako, Japan

An upgrade plan for the RIKEN RI-Beam Factory[1] is under discussion, the objective being to significantly increase the uranium beam intensity. In the upgrade plan, the existing ring cyclotron called RRC[2] will be replaced by a new linac, mainly consisting of superconducting (SC) cavities. The new linac is designed to accelerate heavy ions with a mass-to-charge ratio of ~7, such as 238U³⁵⁺, up to an energy of 11 MeV/u in the cw mode. The present injector linac, RILAC2[3], will be used for the low-energy end, and a short room-temperature (RT) section will be added to RILAC2, which will boost the beam energy up to 1.4 MeV/u. The succeeding SC section consists of 14 cryomodules, each of which contains four quater-wavelength resonators (QWRs) with two gaps operated at 73 MHz. A RT quadrupole doublet is placed in each gap between the cryomodules. The modular configuration of the SC section was optimized based on the first-order approximation for the transverse and longitudinal motions. The designs of SC QWR were carried out using CST Microwave Studio 2013. Further study is under way on the SC QWR including the mechanical considerations, and we also start a design of cryostats.
[1] Y. Yano, Nucl. Instr. Meth. B 261, 1009 (2007).
[2] Y. Yano, Proc. 13th Int. Cyclo. Conf., 102 (1992).
[3] K. Yamada et al., Proc. of IPAC'12, TUOBA02, 1071 (2012).