IPAC2012 - List of Keywords (cyclotron)

Paper	Title	Other Keywords	Page
MOOBA01	Thorium Energy Futures	neutron, target, proton, linac	29
	S. Peggs, W. Horak, T. Roser BNL, Upton, Long Island, New York, USA V.B. Ashley, R.F. Ashworth Jacobs Engineering, Pasadena, USA R.J. Barlow, R. Cywinski, R. Seviour University of Huddersfield, Huddersfield, United Kingdom J.-L. Biarrotte IPN, Orsay, France S. Henderson Fermilab, Batavia, USA A. Hutton JLAB, Newport News, Virginia, USA J. Kelly Thor Energy, Oslo, Norway M. Lindroos ESS, Lund, Sweden P.M. McIntyre Texas A&M University, College Station, Texas, USA A. Norlin IThEO, Sweden H.L. Owen STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G.T. Parks University of Cambridge, Cambridge, United Kingdom
	The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options – liquid or solid, with or without an accelerator – can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice.
	Slides MOOBA01 [3.887 MB]

MOPPC009	Multipactor for E-cloud Diagnostics	electron, resonance, vacuum, dipole	139
	P. Costa Pinto, F. Caspers, P. Edwards, M. Holz, M. Taborelli CERN, Geneva, Switzerland
	Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed though a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic field. Preliminary result show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the event of a large scale coating production this technique will be a valuable resource for quality control.

MOPPC046	End-to-End G4Beamline Simulation of an Inverse Cyclotron for Muon Cooling	simulation, emittance, solenoid, extraction	238
	T.L. Hart, T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA K. Paul Tech-X, Boulder, Colorado, USA
	An inverse cyclotron is a novel, intriguing idea for muon cooling necessary for proposed neutrino factories and muon colliders. We present the latest results of an end-to-end inverse cyclotron simulation that cools muons in the following sequence: single turn injection and initial cooling of 100 MeV kinetic energies to about 5 MeV with lithium hydrogen wedges; further substantial cooling to keV range kinetic energies and trapping with carbon foils and a rising electric field; and re-acceleration of the cooled, trapped muons back to 100 MeV. For neutrino factory and muon collider applications, the time of the entire cooling/trapping/re-acceleration process needs to be comparable to the muon lifetime so that decay losses are tolerable and the acceptance of the inverse cyclotron needs to be sufficiently large (on order 10 mm-rad normalized emittance). The latest progress toward these ends is presented.

MOPPC069	Quantitative Simulation of NIRS-930 Cyclotron	acceleration, extraction, simulation, electromagnetic-fields	292
	V.L. Smirnov, S.B. Vorozhtsov JINR/DLNP, Dubna, Moscow region, Russia A. Goto, S. Hojo, T. Honma, K. Katagiri NIRS, Chiba-shi, Japan
	The results of the computer modelling of the structural elements of the NIRS-930 cyclotron operational at the National Institute of Radiological Sciences (Chiba, Japan) are presented. The integrated approach to modelling of the cyclotron, including calculation of electromagnetic fields of the structural elements and beam dynamics simulations is described. A computer model of the cyclotron was constructed. Electric and magnetic field distributions and mechanical structures were converted to the beam dynamics code for simulations, in which particle losses on the surfaces of the system elements were estimated. The existing data on the axial injection, magnetic, acceleration and extraction systems of the cyclotron and beam parameter measurements are used for calibration of the simulations. New acceleration regimes could be formulated with the help of the constructed computer model of the machine.

MOPPC091	Parallel 3D Simulations to Support Commissioning of a Solenoid-based LEBT Test Stand	simulation, rfq, solenoid, emittance	349
	B.T. Schwartz, D.T. Abell, D.L. Bruhwiler, Y. Choi, S. Mahalingam, P. Stoltz, J. von Stecher Tech-X, Boulder, Colorado, USA B. Han, M.P. Stockli ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844. A solenoid-based low-energy beam transport (LEBT) test stand is under development for the Spallation Neutron Source (SNS). To support commissioning of the test stand, the parallel Vorpal framework is being used for 3D electrostatic particle-in-cell (PIC) simulations of H⁻ beam dynamics in the LEBT, including impact ionization physics and MHz chopping of the partially-neutralized \Hm beam. Here we describe the process of creating a partially-neutralized beam and examine the effects of a single chopping event on the beam's emittance.

MOPPD023	Correction of the nu_r=3/2 Resonance in TRIUMF Cyclotron	resonance, TRIUMF, extraction, simulation	415
	T. Planche, R.A. Baartman, Y.-N. Rao TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Imperfections in the TRIUMF cyclotron are a source of field errors which slightly violate the 6-fold symmetry of the ring. Among them, the third harmonic of the magnetic gradient errors drives the ν_r=3/2 resonance. This results in a modulation of the current density versus radius observed after the resonance crossing all the way to the extraction (480 MeV). The cyclotron has sets of harmonic correction coils at different radii, each set constituted of 6 pairs of coils placed in a 6-fold symmetrical manner. The 6-fold symmetry of this layout makes that a single set of harmonic coils cannot provide a full correction of third harmonic errors driving the ν_r=3/2 resonance. The last two sets of harmonic correction coils (number 12 and 13) are azimuthally displaced. In this study, we use this fact to achieve a full correction of the resonance. We also present experimental measurements that demonstrate the full correction.

MOPPD024	C70 Arronax in the Hands-On Phase	target, proton, simulation, injection	418
	F. Poirier, S. Auduc, L. Lamouric SUBATECH, Nantes, France S. Girault, F. Gomez, E. Mace Cyclotron ARRONAX, Saint-Herblain, France C. Huet EMN, Nantes, France
	The C70 Arronax, is a high-intensity (2x375 μA) and high-energy (70 MeV) multiparticle cyclotron that started its hands-on phase in December 2010. The operating and maintenance group is accumulating experience on this machine. A review of the machine status and present possibilities in terms of beam capacities is thus presented in this paper. The status of the beamline simulations is also given.

MOPPD026	A Superconducting Ring Cyclotron for the DAEδALUS Experiment	extraction, proton, injection, focusing	421
	L. Calabretta INFN/LNS, Catania, Italy A. Calanna, D. Campo CSFNSM, Catania, Italy M.M. Maggiore, L.A.C. Piazza INFN/LNL, Legnaro (PD), Italy F. Méot BNL, Upton, Long Island, New York, USA
	Funding: Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud. The experiment DAEδALUS, proposed by MIT scientist to search for CP violation in the neutrino sector, needs three accelerator with energy of about 800 MeV, average power of some MW and duty cycle of 20%. To reduce the cost of the accelerators a cyclotron complex consisting of an injector* and of a booster ring cyclotron has been proposed**. The booster Superconducting Ring Cyclotron is able to accelerate a H²⁺ molecule beam up to 800 MeV/n with a peak current of 10 mA and average power higher than 1.6 MW. To simplify the design of the superconducting magnetic coils, to minimize the radial force shift and to increase the room to host the RF cavities, the previous study has been updated increasing the injection energy of the H²⁺ and also the injection energy. The updated study on the magnetic sector configuration, on the superconducting coils and the magnetic forces are presented. The isochronous magnetic field, the beam dynamics along the injection and extraction path and during the acceleration are presented, too. J. Alonso et al., Jun2010 e-Print: arXiv:1006.0260 L. Calabretta, Proc. IPAC 2011, WEPS073 (2011). * L. Calabretta, Cyclotrons 2010, Lanzhou.

MOPPD027	A Compact High Intensity Cyclotron Injector for DAEδALUS Experiment	extraction, resonance, beam-losses, simulation	424
	L. Calabretta, D. Rifuggiato INFN/LNS, Catania, Italy A. Adelmann Paul Scherrer Institut, Villigen, Switzerland A. Calanna, D. Campo CSFNSM, Catania, Italy M.M. Maggiore, L.A.C. Piazza INFN/LNL, Legnaro (PD), Italy J.J. Yang CIAE, Beijing, People's Republic of China
	Funding: Istituto Nazionale di Fisica Nucleare - Laboratori Nazionale del Sud. The experiment DAEδALUS, recently proposed by MIT scientist to search for CP violation in the neutrino sector, needs three accelerator with energy of about 800 MeV, average power of some MW and duty cycle of 20%. To reduce the cost of the accelerators a cyclotron complex consisting of an injector and of a booster ring cyclotron has been proposed. The main characteristics of the new kind of separated sector cyclotron injector able to accelerate a H²⁺ molecule beam up to 60 MeV/n will be presented. Due to the low duty cycle, the peak current to be accelerated is 5 mA. The problem related to the injection of a H²⁺ beam, delivered by a compact ion source, and to the space charge effects will be discussed. To allow an easier injection in the booster Superconducting Ring Cyclotron the extraction energy has been increased up to 60 MeV/n. The pole gap was decreased to 60 mm to achieve a more efficient beam extraction. The updated configuration of the magnetic sectors, of the isochronous magnetic field and beam dynamics along extraction path and during the acceleration will be presented, too. J. Alonso et al., "Novel Search for CP Violation in the Neutrino Sector: DAEδALUS," Jun2010 e-Print: arXiv:1006.0260 ** L. Calabretta, Proc. of IPAC 2011, WEPS073, p. 2673 (2011).

MOPPD028	Observation of Longitudinal Space Charge Effects in the Injection Beam Line of NIRS-930 Cyclotron	bunching, space-charge, injection, simulation	427
	S. Hojo, A. Goto, T. Honma, K. Katagiri, A. Sugiura NIRS, Chiba-shi, Japan
	Dependence of bunching efficiencies on the position of a beam buncher was measured for the AVF cyclotron at the National Institute of Radiological Sciences (NIRS) for 30 MeV proton beams with intensities up to 100 microamperes at injection. The measurement was carried out for two positions: 1.53 m and 2.33 m upstream from the inflector. For the buncher position of 2.33 m the bunching efficiency decreased, as the beam intensity increased, to about half of that at low intensities, while for 1.5 m it was constant up to 100 microamperes. The intensity distributions of extracted beam with respect to the buncher phase were also measured for the two buncher positions. The dependence of bunch width on the beam intensity is discussed by comparing the data with one-dimensional simulations on longitudinal space charge effects.

MOPPD029	Recent Achievements and Upgrade Programs at RIKEN Radioactive Isotope Beam Factory	ion, ECRIS, electron, linac	430
	H. Okuno, T. Dantsuka, M. Fujimaki, T. Fujinawa, N. Fukunishi, H. Hasebe, Y. Higurashi, K. Ikegami, E. Ikezawa, H. Imao, T. Kageyama, O. Kamigaito, M. Kase, M. Kidera, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, M. Nakamura, J. Ohnishi, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa RIKEN Nishina Center, Wako, Japan
	Recent achievements and upgrade programs in the near future at RIKEN Radioactive Isotope Beam Factory (RIBF) are presented. The beam intensity and available ion species are increasing at RIBF, owing to the continuous efforts that have been paid since the first beam in 2006. So far, we accelerated deuteron, helium, nitrogen, oxygen, aluminum, calcium, krypton, and uranium beams with the world's first superconducting ring cyclotron, SRC. The extracted beam intensities reached 1,000 pnA for helium and oxygen beams. From the operational point of view, however, the intensity of the uranium beam should be much increased. Therefore we constructed a new injector system for the RIBF, consisting of a 28 GHz ECR ion sources, RFQ and DTL, which was successfully commissioned in the end of 2010. Furthermore we developed low-Z (low atomic number Z) gas stripper* alternative to standard carbon foil stripping, which will be reliable and efficient charge stripping scheme for such high-power uranium beams. * H. Okuno et al., IEEE Trans. Appl. Supercond., 18, 226 (2008). ** H. Okuno et al., Phys. Rev. ST Accel. Beams 14, 033503 (2011).

MOPPD030	Present Status of RIKEN Ring Cyclotron	ion, heavy-ion, linac, vacuum	433
	Y. Watanabe, M. Fujimaki, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, T. Kageyama, O. Kamigaito, M. Kase, M. Kidera, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, K. Yamada, S. Yokouchi RIKEN Nishina Center, Wako, Japan T. Aihara, S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, Y. Kotaka, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, T.O. Ohki, K. Oyamada, J. Shibata, M. Tamura, N. Tsukiori, A. Uchiyama, K. Yadomi, H. Yamauchi SHI Accelerator Service Ltd., Tokyo, Japan
	The RIKEN Ring Cyclotron (RRC K540) has been in stable operation over twenty-five years, and supplying many kinds of heavy-ion beams to experiments. Since 2007, it has also been supplying beams to the RIBF four Ring cyclotrons including the Super-conducting Ring Cyclotron (SRC K2500). Now the RRC has three kinds of injectors, one is K70 AVF cyclotron for light ions, the second is the variable-frequency linac for heavy ions, and the third is the RILAC2 for using the high intensity very heavy ions like U and Xe. The many combinations of accelerators are possible, and in any acceleration modes, the RRC should works as a first energy booster. A total operation time of the RRC is more than 5000 hr in every year. The present status of the RRC operation will be reported.

MOPPD033	Strong-focusing Cyclotron - High-current Applications	dipole, proton, focusing, cavity	436
	P.M. McIntyre, S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, J.N. Kellams, T.L. Mann, A.D. McInturff, N. Pogue, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: This work is supported by grants from the State of Texas (ASE) and from the Mitchell Family Foundation. Quadrupole focusing channels are integrated into the pole faces of a superconducting sector cyclotron, to enable control of the betatron tunes for all orbits. This provision makes it possible to lock the tunes to desired values for all orbits, thereby eliminating resonance crossing and facilitating local orbit bumps for injection and extraction. Optical control is of particular importance for applications where higher beam current is desired, for ADS fission drivers, for spallation neutron sources, and for medical isotope production.

MOPPD034	Flux-coupled Stacking of Cyclotrons for a High-power ADS Fission Driver	injection, cavity, focusing, target	439
	A. Sattarov, S. Assadi, K.E. Badgley, J.N. Kellams, T.L. Mann, A.D. McInturff, P.M. McIntyre, N. Pogue Texas A&M University, College Station, Texas, USA
	Funding: This work is funded by grants from the State of Texas (ASE) and the Mitchell Family Foundation. The sector magnets for an isochronous cyclotron are configured as a flux-coupled stack of apertures, each forming an independent cyclotron, separated sufficiently to accommodate independent superconducting rf cavities. The stack strategy makes it possible to deliver any amount of proton beam power consistent with the limitations of each individual cyclotron, and to deliver the aggregate power to a number of spallation targets as dictated by optimum coupling for accelerator-driven subcritical (ADS) fission and by limitations in target transfer.

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

TUPPD047	Injection Sequence for High-power Isochronous Cyclotrons for ADS Fission	ion, rfq, ion-source, emittance	1509
	S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, P.M. McIntyre, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: This work is supported by grants from the State of Texas (ASE) and the Mitchell Family Foundation. A high-current injector sequence is being developed for use in a flux-coupled stack of high-current cyclotrons for accelerator-driven subcritical (ADS) fission. The design includes an ECR ion source, LEBT, RF quadrupole, and multi-stage chopper. A first cyclotron then accelerates the beams to 100 MeV for injection to the sector isochronous cyclotron. Provisions for control of emittance and bunch tails are described.

TUPPR087	Status of NSCL Cyclotron Gas Stopper	ion, extraction, injection, emittance	2029
	N.S. Joshi, G. Bollen, M. Brodeur, D.J. Morrissey, S. Schwarz NSCL, East Lansing, Michigan, USA
	A gas-filled reverse cyclotron for the thermalization of energetic beams is under construction at NSCL/MSU. Rare isotopes produced via projectile fragmentation after in-flight separation will be injected into the device and converted into low-energy beams through buffer gas interactions as they spiral towards the center of the device. The extracted thermal beams will be used for low energy experiments such as precision mass measurements with traps or laser spectroscopy, and further transport for reacceleration. Detailed calculations have been performed to optimize the magnetic field design as well as the transport and stopping of ions inside the gas. An RF-carpet will be used to transport the thermal ions to the axial extraction point. The calculations indicate that the cyclotron gas stopper will be much more efficient for the thermalization of light and medium mass ions compared to linear gas cells. In this contribution we will discuss simulations of the overall performance and acceptance of machine, the beam matching calculations to the fragment separator emittance, and the construction status.

WEPPC063	Superconducting RF Cavity for High-current Cyclotrons	cavity, focusing, extraction, injection	2354
	N. Pogue, P.M. McIntyre, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: This work is supported by grants from the State of Texas (ASE) and the Mitchell Family Foundation. A novel superconducting cavity is presented for applications in cyclotrons. The cavity is in effect an extrusion of a 2-D double-quarter-wave structure, in which the ends of the extrusion are wrapped around and joined so that the cavity has no end perturbations. Power is applied to a linear array of input coupling loops, so that rf sheet current is launched in a laminar flow that matches the power coupled to the orbits of the cyclotron. Each loop is driven by an independent solid-state rf source. A strategy is presented for using to advantage the independent control of phase and amplitude to suppress transient phenomena. Longitudinal modes can be strongly suppressed. These provisions are of importance to suppress phenomena that can limit beam current.

WEPPD066	Design of a Stripline Kicker for Tune Measurement in CSNS RCS	kicker, impedance, lattice, wakefield	2675
	X.Y. Yang, S. Fu, T.G. Xu IHEP, Beijing, People's Republic of China
	For CSNS RCS tune measurement, tune value is measured by exciting the bunch with strip-line kicker fed with white noise and using FFT algorithm to the turn-by-turn position of the bunch in the BPM. This article simulates the strip-line kicker in RCS and the efficiency of the kicker is discussed in the MATLAB environment. The parameters of the kicker with arc electrode structure such as wake impedance, thermal state and VSWR are analyzed based on the advantage of this design.

WEPPP011	Multi-Cavity Proton Cyclotron Accelerator: An Electron Counterpart	cavity, proton, electron, acceleration	2744
	M.A. LaPointe, S.V. Shchelkunov Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA J.L. Hirshfield Omega-P, Inc., New Haven, USA V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Supported by the Department of Energy, Office of Nuclear Physics. A multi-cavity multi-frequency proton cyclotron accelerator has been proposed. It would utilize cyclotron resonance in each of eight cavities of uniformly diminishing frequency in a uniform magnetic field to comprise a compact (25 m) 1 GeV proton accelerator, according to simulation results. A four cavity electron counterpart is under construction to test the mechanism of the multi-cavity setup, including phase acceptance, energy gain, and growth of energy spread and emittance for parameters equivalent to the proton case. The four electron counterpart cavities are driven by kW-level phase coherent RF sources at 1.5, 1.8, 2.1 and 2.4 GHz. Each cavity operates in the rotating TE111 mode and includes two feeds in quadrature to drive the rotating mode and two RF pickoffs for diagnostics. The electron beam source is a low-current gun with a BaO cathode which operates at -1200V and <50 microamps. After traversing the cavities, the beam is collected on either a Faraday cup or is imaged with a phosphor screen. Details of the setup and initial results from experiments with the four cavity electron counterpart will be presented. M.A. LaPointe, V.P. Yakovlev, S.Yu. Kazakov, and J.L. Hirshfield, Proc. of PAC 2009, May 4-8,Vancouver, BC, Canada, pp.3045-3047 (2011).

THEPPB003	A 1 GeV CW FFAG High Intensity Proton Driver	space-charge, emittance, simulation, focusing	3234
	S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom C. Johnstone Fermilab, Batavia, USA
	The drive for high beam power, high duty cycle, and reliable beams at reasonable cost has focused world attention on fixed-field accelerators, notably Fixed-Field Alternating Gradient accelerators (FFAGs). High-intensity GeV proton drivers are of particular interest, as these encounter duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotron. Recently, the concept of isochronous orbits has been explored and developed for non-scaling FFAGs using powerful new methodologies in FFAG accelerator design. These new breeds of FFAGs have been identified by international collaborations for serious study thanks to their potential applications including Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste. The extreme reliability requirements for ADS mandate CW operation capability and the FFAG’s strong focusing, particularly in the vertical, will serve to mitigate the effect of space charge (as compared with the weak-focusing cyclotron). This paper reports on these new advances in FFAG accelerator technology and presents a stable, 0.25-1GeV isochronous FFAG for an accelerator driven subcritical reactor.

THPPC001	Simulation and Design of a 70 MeV Cyclotron RF System	simulation, cavity, vacuum, resonance	3269
	G. Gold, R.R. Johnson, B.F. Milton, V. Sabaiduc BCSI, Vancouver, BC, Canada
	The electromagnetic and mechanical design of the resonant cavity for a 70 MeV compact commercial cyclotron has been conducted by Best Cyclotron Systems Inc. Various resonator configurations have been studied for a radial, single-stem design and an optimal solution was selected with excellent electromagnetic properties and minimized construction and operational cost. Rapid model iterations during the design, using CST Microwave Studio and ANSYS, allowed for accurate tuning of geometry to precisely define the shape of the accelerating voltage profile, surface current distribution, and total power loss. The RF system of the BEST 70p cyclotron will operate at the fourth harmonic with two λ/2 separated resonant cavities shielded at the center allowing for beam modulation techniques to be applied through phase modulation of the accelerating voltage.

THPPC056	Development of 12kW RF Power Supply for CYCHU-10 Cyclotron	power-supply, cavity, feedback, impedance	3416
	D. Li, T. Hu, J. Huang, K.F. Liu, B. Qin, J. Yang, L. Yang Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China
	One 12kW RF power supply has been developed for CYCHU-10, which is a 10 MeV cyclotron developed in Huazhong University of Science and Technology (HUST). A high performance DDS chip AD9859 is used to synthesize RF signal in this power supply, which is easy to change the output frequency. The centre frequency is 101MHz, and the frequency bandwidth is more than 1MHz. The RF power supply could operate in fine searching mode, coarse searching mode, tracking mode, and so on. It could search the resonant frequency of cavity with the frequency control loop. The final stage amplifier using a triode 3CW20,000H7 operates in grounded grid configuration, which is stable and reliable. The performance test using a 50Ω resistor load has finished, and major results are shown in this paper.

THPPP040	Heavy-ion Beam Acceleration at RIKEN for the Super-Heavy Element Search	ion, target, ion-source, ECR	3823
	M. Kase, M. Fujimaki, Y. Higurashi, E. Ikezawa, O. Kamigaito, M. Komiyama, T. Nakagawa, K. Ozeki, N. Sakamoto, K. Suda RIKEN Nishina Center, Wako, Japan T. Aihara, T.O. Ohki, K. Oyamada, M. Tamura, A. Uchiyama, H. Yamauchi SHI Accelerator Service Ltd., Tokyo, Japan
	In RIKEN Nishina accelerator center, the experiment on the super-heavy element (Z=113) search has been being carried out since 2003. The RIKEN heavy-ion linac is supplying a heavy-ion beam of 70Zn with energies around 5MeV/nucleon. The beam intensities are required more than 1 particle maicro amper on the target. Very long-term and stable operations are intrinsic for this kind of experiments. So far two events for Z=113 have been found during a net irradiation time of 10345 hours (431 days) with a total dose 1.1 x 10²⁰ (12.8 mg). Heavy operation of the linac will be reported.

THPPP077	Status of the SPES Project: a Neutron Rich ISOL Facility for Re-accelerated RIBs	target, ISOL, neutron, proton	3913
	L.A.C. Piazza, A. Andrighetto, G. Bisoffi, P. Favaron, F. Gramegna, A. Lombardi, G.P. Prete, D. Zafiropoulos INFN/LNL, Legnaro (PD), Italy L. Calabretta INFN/LNS, Catania, Italy
	SPES (Selective Production of Exotic Species) is an INFN project with the aim to develop a Radioactive Ion Beam (RIB) facility as an intermediate step toward EURISOL. The SPES Project is under realization at the INFN Legnaro National Laboratories site. The SPES Project main goal is to provide a production and accelerator system of exotic beams to perform forefront research in nuclear physics by studying nuclei far from stability. The SPES Project is concentrating on the production of neutron-rich radioactive nuclei with mass in the range 80-160. The final energy of the radioactive beams on target will range from few MeV/u up to 11 MeV/u for A=130. The SPES acceleration system will be presented, together with the facility realization status.

THPPP084	Charge Stripping of Uranium-238 Ion Beam with Helium Gas Stripper	target, ion, acceleration, radiation	3930
	H. Imao RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan N. Fukunishi, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, H. Okuno, T. Watanabe, Y. Watanabe, Y. Yano, S. Yokouchi RIKEN Nishina Center, Wako, Japan
	Development of the reliable and efficient electric charge stripping method is one of the key issues in next-generation high-intensity heavy ion accelerators. Although conventional carbon-foil charge strippers provide a good charge stripping efficiency, two serious problems are emerging; the short usable time and thickness non-uniformity. A charge stripper using low-Z gas is an important candidate applicable for high-intensity 238U beams to replace carbon foil strippers. In the present work, the first actual charge stripping system using helium gas for 238U beams injected at 10.75 MeV/u has been developed and tested.

THPPR053	A CW FFAG for Proton Computed Tomography	proton, extraction, lattice, acceleration	4094
	C. Johnstone, D.V. Neuffer Fermilab, Batavia, USA H.L. Owen STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P. Snopok IIT, Chicago, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy An advantage of the cyclotron in proton therapy is the continuous (CW) beam output which reduces complexity and response time in the dosimetry requirements and beam controls. A CW accelerator requires isochronous particle orbits at all energies through the acceleration cycle and present compact isochronous cyclotrons for proton therapy reach only 250 MeV (kinetic energy) which is required for patient treatment, but low for full Proton Computed Tomography (PCT) capability. PCT specifications need 300-330 MeV in order for protons to transit the human body. Recent innovations in nonscaling FFAG design have achieved isochronous performance in a compact (~3 m radius) design at these higher energies. Preliminary isochronous designs are presented here. Lower energy beams can be efficiently extracted for patient treatment without changes to the acceleration cycle and magnet currents.

THPPR063	1 GeV CW Nonscaling FFAG for ADS, and Magnet Parameters	extraction, lattice, simulation, proton	4118
	F. Méot, W.-T. Weng BNL, Upton, Long Island, New York, USA C. Johnstone Fermilab, Batavia, USA P. Snopok Illinois Institute of Technology, Chicago, IL, USA
	Multi-MW proton driver capability remains a challenging, critical technology for many core HEP programs, particularly the neutrino ones such as the Muon Collider and Neutrino factory, and for next generation energy applications such as Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste for nuclear power and waste management. Work is focused almost exclusively on an SRF linac, as, to date, no re-circulating accelerator can attain the 10^-20 MW capability necessary for the nuclear applications. Recently, the concept of isochronous orbits has been explored and developed for nonscaling FFAGs using powerful new methodologies in FFAG accelerator design. The FFAG can remain isochronous beyond the energy reach of cyclotrons and with fixed magnetic fields and strong focusing coupled to recent advances in tune stability, dynamic aperture, and footprint, serious study is underway on a potential application to the ADS problem. Work is progressing on a stable, high intensity, 0.25-1GeV isochronous FFAG. Development and studies of novel magnets with the nonlinear radial fields required to support isochronous operation are reported here.

THPPR064	MW-class 800 MeV/n H²⁺ SC-Cyclotron for ADC application, Design Study and Goals	extraction, injection, target, closed-orbit	4121
	F. Méot, T. Roser, W.-T. Weng BNL, Upton, Long Island, New York, USA L. Calabretta INFN/LNS, Catania, Italy A. Calanna CSFNSM, Catania, Italy
	A megawatt class isochronous cyclotron is a potential candidate for accelerator driven systems, as in the subcritical-fission molten-salt reactor application. A scheme for a 800 MeV/nucleon cyclotron accelerating molecular H₂⁺ has been derived from on-going proton driver design studies for neutrino beam production. The present paper reports on beam dynamics studies regarding that cyclotron, exploiting its superconducting coil magnetic sector OPERA field map. These studies are aimed at assessing lattice properties as accelerated orbit, phase oscillations, tunes, beam envelopes and other resonance effects.

THPPR073	Target Studies for the Production of Lithium 8 for Neutrino Physics Using a Low Energy Cyclotron	target, neutron, proton, simulation	4145
	A. Bungau, R.J. Barlow University of Huddersfield, Huddersfield, United Kingdom J.M. Conrad, J. Spitz MIT, Cambridge, Massachusetts, USA M. Shaevitz Columbia University, New York, USA
	Lithium 8 is a short lived beta emitter producing a high energy anti-neutrino, which is very suitable for making several measurements of fundamental quantities. It is proposed to produce Lithium 8 with a commercially available 60 MeV cyclotron using protons or alpha particles on a Beryllium 9 target. We have used the GEANT4 program to model these processes, and calculate the antineutrino fluxes that could be obtained in a practical system. We also calculate the production of undesirable contaminants such as Boron 8, and show that these can be reduced to a very low level.

THPPR076	Optimising Neutron Production From Compact Low Energy Accelerators	target, neutron, proton, simulation	4154
	N. Ratcliffe, R.J. Barlow, A. Bungau, R. Cywinski University of Huddersfield, Huddersfield, United Kingdom T.R. Edgecock STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	There is currently much development in accelerator based methods to provide flexible and reliable neutron generators, in response to a decline in the availability of nuclear reactors. In this paper the focus is on neutron production via a low energy DC proton accelerator (1-10 MeV) and light target system. GEANT4 simulations are being used to study various aspects of target design, beginning with studies into light targets, such as lithium and beryllium, which are already in use. Initially the aim is to replicate these designs and benchmark these simulations, with other models and experimental results, before investigating how modifications can improve neutron production and tailor experimental geometries to specific applications such as neutron capture therapy and medical isotope production.

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MOOBA01

Thorium Energy Futures

neutron, target, proton, linac

29

S. Peggs, W. Horak, T. Roser
BNL, Upton, Long Island, New York, USA
V.B. Ashley, R.F. Ashworth
Jacobs Engineering, Pasadena, USA
R.J. Barlow, R. Cywinski, R. Seviour
University of Huddersfield, Huddersfield, United Kingdom
J.-L. Biarrotte
IPN, Orsay, France
S. Henderson
Fermilab, Batavia, USA
A. Hutton
JLAB, Newport News, Virginia, USA
J. Kelly
Thor Energy, Oslo, Norway
M. Lindroos
ESS, Lund, Sweden
P.M. McIntyre
Texas A&M University, College Station, Texas, USA
A. Norlin
IThEO, Sweden
H.L. Owen
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G.T. Parks
University of Cambridge, Cambridge, United Kingdom

The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options – liquid or solid, with or without an accelerator – can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice.

Slides MOOBA01 [3.887 MB]

MOPPC009

Multipactor for E-cloud Diagnostics

electron, resonance, vacuum, dipole

139

P. Costa Pinto, F. Caspers, P. Edwards, M. Holz, M. Taborelli
CERN, Geneva, Switzerland

Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed though a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic field. Preliminary result show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the event of a large scale coating production this technique will be a valuable resource for quality control.

MOPPC046

End-to-End G4Beamline Simulation of an Inverse Cyclotron for Muon Cooling

simulation, emittance, solenoid, extraction

238

T.L. Hart, T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA
K. Paul
Tech-X, Boulder, Colorado, USA

An inverse cyclotron is a novel, intriguing idea for muon cooling necessary for proposed neutrino factories and muon colliders. We present the latest results of an end-to-end inverse cyclotron simulation that cools muons in the following sequence: single turn injection and initial cooling of 100 MeV kinetic energies to about 5 MeV with lithium hydrogen wedges; further substantial cooling to keV range kinetic energies and trapping with carbon foils and a rising electric field; and re-acceleration of the cooled, trapped muons back to 100 MeV. For neutrino factory and muon collider applications, the time of the entire cooling/trapping/re-acceleration process needs to be comparable to the muon lifetime so that decay losses are tolerable and the acceptance of the inverse cyclotron needs to be sufficiently large (on order 10 mm-rad normalized emittance). The latest progress toward these ends is presented.

MOPPC069

Quantitative Simulation of NIRS-930 Cyclotron

acceleration, extraction, simulation, electromagnetic-fields

292

V.L. Smirnov, S.B. Vorozhtsov
JINR/DLNP, Dubna, Moscow region, Russia
A. Goto, S. Hojo, T. Honma, K. Katagiri
NIRS, Chiba-shi, Japan

The results of the computer modelling of the structural elements of the NIRS-930 cyclotron operational at the National Institute of Radiological Sciences (Chiba, Japan) are presented. The integrated approach to modelling of the cyclotron, including calculation of electromagnetic fields of the structural elements and beam dynamics simulations is described. A computer model of the cyclotron was constructed. Electric and magnetic field distributions and mechanical structures were converted to the beam dynamics code for simulations, in which particle losses on the surfaces of the system elements were estimated. The existing data on the axial injection, magnetic, acceleration and extraction systems of the cyclotron and beam parameter measurements are used for calibration of the simulations. New acceleration regimes could be formulated with the help of the constructed computer model of the machine.

MOPPC091

Parallel 3D Simulations to Support Commissioning of a Solenoid-based LEBT Test Stand

simulation, rfq, solenoid, emittance

349

B.T. Schwartz, D.T. Abell, D.L. Bruhwiler, Y. Choi, S. Mahalingam, P. Stoltz, J. von Stecher
Tech-X, Boulder, Colorado, USA
B. Han, M.P. Stockli
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844.
A solenoid-based low-energy beam transport (LEBT) test stand is under development for the Spallation Neutron Source (SNS). To support commissioning of the test stand, the parallel Vorpal framework is being used for 3D electrostatic particle-in-cell (PIC) simulations of H⁻ beam dynamics in the LEBT, including impact ionization physics and MHz chopping of the partially-neutralized \Hm beam. Here we describe the process of creating a partially-neutralized beam and examine the effects of a single chopping event on the beam's emittance.

MOPPD023

Correction of the nu_r=3/2 Resonance in TRIUMF Cyclotron

resonance, TRIUMF, extraction, simulation

415

T. Planche, R.A. Baartman, Y.-N. Rao
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Imperfections in the TRIUMF cyclotron are a source of field errors which slightly violate the 6-fold symmetry of the ring. Among them, the third harmonic of the magnetic gradient errors drives the ν_r=3/2 resonance. This results in a modulation of the current density versus radius observed after the resonance crossing all the way to the extraction (480 MeV). The cyclotron has sets of harmonic correction coils at different radii, each set constituted of 6 pairs of coils placed in a 6-fold symmetrical manner. The 6-fold symmetry of this layout makes that a single set of harmonic coils cannot provide a full correction of third harmonic errors driving the ν_r=3/2 resonance. The last two sets of harmonic correction coils (number 12 and 13) are azimuthally displaced. In this study, we use this fact to achieve a full correction of the resonance. We also present experimental measurements that demonstrate the full correction.

MOPPD024

C70 Arronax in the Hands-On Phase

target, proton, simulation, injection

418

F. Poirier, S. Auduc, L. Lamouric
SUBATECH, Nantes, France
S. Girault, F. Gomez, E. Mace
Cyclotron ARRONAX, Saint-Herblain, France
C. Huet
EMN, Nantes, France

The C70 Arronax, is a high-intensity (2x375 μA) and high-energy (70 MeV) multiparticle cyclotron that started its hands-on phase in December 2010. The operating and maintenance group is accumulating experience on this machine. A review of the machine status and present possibilities in terms of beam capacities is thus presented in this paper. The status of the beamline simulations is also given.

MOPPD026

A Superconducting Ring Cyclotron for the DAEδALUS Experiment

extraction, proton, injection, focusing

421

L. Calabretta
INFN/LNS, Catania, Italy
A. Calanna, D. Campo
CSFNSM, Catania, Italy
M.M. Maggiore, L.A.C. Piazza
INFN/LNL, Legnaro (PD), Italy
F. Méot
BNL, Upton, Long Island, New York, USA

Funding: Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud.
The experiment DAEδALUS*, proposed by MIT scientist to search for CP violation in the neutrino sector, needs three accelerator with energy of about 800 MeV, average power of some MW and duty cycle of 20%. To reduce the cost of the accelerators a cyclotron complex consisting of an injector** and of a booster ring cyclotron has been proposed***. The booster Superconducting Ring Cyclotron is able to accelerate a H²⁺ molecule beam up to 800 MeV/n with a peak current of 10 mA and average power higher than 1.6 MW. To simplify the design of the superconducting magnetic coils, to minimize the radial force shift and to increase the room to host the RF cavities, the previous study has been updated increasing the injection energy of the H²⁺ and also the injection energy. The updated study on the magnetic sector configuration, on the superconducting coils and the magnetic forces are presented. The isochronous magnetic field, the beam dynamics along the injection and extraction path and during the acceleration are presented, too.
* J. Alonso et al., Jun2010 e-Print: arXiv:1006.0260
** L. Calabretta, Proc. IPAC 2011, WEPS073 (2011).
*** L. Calabretta, Cyclotrons 2010, Lanzhou.

MOPPD027

A Compact High Intensity Cyclotron Injector for DAEδALUS Experiment

extraction, resonance, beam-losses, simulation

424

L. Calabretta, D. Rifuggiato
INFN/LNS, Catania, Italy
A. Adelmann
Paul Scherrer Institut, Villigen, Switzerland
A. Calanna, D. Campo
CSFNSM, Catania, Italy
M.M. Maggiore, L.A.C. Piazza
INFN/LNL, Legnaro (PD), Italy
J.J. Yang
CIAE, Beijing, People's Republic of China

Funding: Istituto Nazionale di Fisica Nucleare - Laboratori Nazionale del Sud.
The experiment DAEδALUS*, recently proposed by MIT scientist to search for CP violation in the neutrino sector, needs three accelerator with energy of about 800 MeV, average power of some MW and duty cycle of 20%. To reduce the cost of the accelerators a cyclotron complex consisting of an injector and of a booster ring cyclotron has been proposed**. The main characteristics of the new kind of separated sector cyclotron injector able to accelerate a H²⁺ molecule beam up to 60 MeV/n will be presented. Due to the low duty cycle, the peak current to be accelerated is 5 mA. The problem related to the injection of a H²⁺ beam, delivered by a compact ion source, and to the space charge effects will be discussed. To allow an easier injection in the booster Superconducting Ring Cyclotron the extraction energy has been increased up to 60 MeV/n. The pole gap was decreased to 60 mm to achieve a more efficient beam extraction. The updated configuration of the magnetic sectors, of the isochronous magnetic field and beam dynamics along extraction path and during the acceleration will be presented, too.
* J. Alonso et al., "Novel Search for CP Violation in the Neutrino Sector: DAEδALUS," Jun2010 e-Print: arXiv:1006.0260
** L. Calabretta, Proc. of IPAC 2011, WEPS073, p. 2673 (2011).

MOPPD028

Observation of Longitudinal Space Charge Effects in the Injection Beam Line of NIRS-930 Cyclotron

bunching, space-charge, injection, simulation

427

S. Hojo, A. Goto, T. Honma, K. Katagiri, A. Sugiura
NIRS, Chiba-shi, Japan

Dependence of bunching efficiencies on the position of a beam buncher was measured for the AVF cyclotron at the National Institute of Radiological Sciences (NIRS) for 30 MeV proton beams with intensities up to 100 microamperes at injection. The measurement was carried out for two positions: 1.53 m and 2.33 m upstream from the inflector. For the buncher position of 2.33 m the bunching efficiency decreased, as the beam intensity increased, to about half of that at low intensities, while for 1.5 m it was constant up to 100 microamperes. The intensity distributions of extracted beam with respect to the buncher phase were also measured for the two buncher positions. The dependence of bunch width on the beam intensity is discussed by comparing the data with one-dimensional simulations on longitudinal space charge effects.

MOPPD029

Recent Achievements and Upgrade Programs at RIKEN Radioactive Isotope Beam Factory

ion, ECRIS, electron, linac

430

H. Okuno, T. Dantsuka, M. Fujimaki, T. Fujinawa, N. Fukunishi, H. Hasebe, Y. Higurashi, K. Ikegami, E. Ikezawa, H. Imao, T. Kageyama, O. Kamigaito, M. Kase, M. Kidera, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, M. Nakamura, J. Ohnishi, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa
RIKEN Nishina Center, Wako, Japan

Recent achievements and upgrade programs in the near future at RIKEN Radioactive Isotope Beam Factory (RIBF) are presented. The beam intensity and available ion species are increasing at RIBF, owing to the continuous efforts that have been paid since the first beam in 2006. So far, we accelerated deuteron, helium, nitrogen, oxygen, aluminum, calcium, krypton, and uranium beams with the world's first superconducting ring cyclotron, SRC*. The extracted beam intensities reached 1,000 pnA for helium and oxygen beams. From the operational point of view, however, the intensity of the uranium beam should be much increased. Therefore we constructed a new injector system for the RIBF, consisting of a 28 GHz ECR ion sources, RFQ and DTL, which was successfully commissioned in the end of 2010. Furthermore we developed low-Z (low atomic number Z) gas stripper** alternative to standard carbon foil stripping, which will be reliable and efficient charge stripping scheme for such high-power uranium beams.
* H. Okuno et al., IEEE Trans. Appl. Supercond., 18, 226 (2008).
** H. Okuno et al., Phys. Rev. ST Accel. Beams 14, 033503 (2011).

MOPPD030

Present Status of RIKEN Ring Cyclotron

ion, heavy-ion, linac, vacuum

433

Y. Watanabe, M. Fujimaki, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, T. Kageyama, O. Kamigaito, M. Kase, M. Kidera, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, K. Yamada, S. Yokouchi
RIKEN Nishina Center, Wako, Japan
T. Aihara, S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, Y. Kotaka, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, T.O. Ohki, K. Oyamada, J. Shibata, M. Tamura, N. Tsukiori, A. Uchiyama, K. Yadomi, H. Yamauchi
SHI Accelerator Service Ltd., Tokyo, Japan

The RIKEN Ring Cyclotron (RRC K540) has been in stable operation over twenty-five years, and supplying many kinds of heavy-ion beams to experiments. Since 2007, it has also been supplying beams to the RIBF four Ring cyclotrons including the Super-conducting Ring Cyclotron (SRC K2500). Now the RRC has three kinds of injectors, one is K70 AVF cyclotron for light ions, the second is the variable-frequency linac for heavy ions, and the third is the RILAC2 for using the high intensity very heavy ions like U and Xe. The many combinations of accelerators are possible, and in any acceleration modes, the RRC should works as a first energy booster. A total operation time of the RRC is more than 5000 hr in every year. The present status of the RRC operation will be reported.

MOPPD033

Strong-focusing Cyclotron - High-current Applications

dipole, proton, focusing, cavity

436

P.M. McIntyre, S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, J.N. Kellams, T.L. Mann, A.D. McInturff, N. Pogue, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: This work is supported by grants from the State of Texas (ASE) and from the Mitchell Family Foundation.
Quadrupole focusing channels are integrated into the pole faces of a superconducting sector cyclotron, to enable control of the betatron tunes for all orbits. This provision makes it possible to lock the tunes to desired values for all orbits, thereby eliminating resonance crossing and facilitating local orbit bumps for injection and extraction. Optical control is of particular importance for applications where higher beam current is desired, for ADS fission drivers, for spallation neutron sources, and for medical isotope production.

MOPPD034

Flux-coupled Stacking of Cyclotrons for a High-power ADS Fission Driver

injection, cavity, focusing, target

439

A. Sattarov, S. Assadi, K.E. Badgley, J.N. Kellams, T.L. Mann, A.D. McInturff, P.M. McIntyre, N. Pogue
Texas A&M University, College Station, Texas, USA

Funding: This work is funded by grants from the State of Texas (ASE) and the Mitchell Family Foundation.
The sector magnets for an isochronous cyclotron are configured as a flux-coupled stack of apertures, each forming an independent cyclotron, separated sufficiently to accommodate independent superconducting rf cavities. The stack strategy makes it possible to deliver any amount of proton beam power consistent with the limitations of each individual cyclotron, and to deliver the aggregate power to a number of spallation targets as dictated by optimum coupling for accelerator-driven subcritical (ADS) fission and by limitations in target transfer.

TUOBA02

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

ion, linac, DTL, ECRIS

1071

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

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

Slides TUOBA02 [9.947 MB]

TUPPD047

Injection Sequence for High-power Isochronous Cyclotrons for ADS Fission

ion, rfq, ion-source, emittance

1509

S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, P.M. McIntyre, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: This work is supported by grants from the State of Texas (ASE) and the Mitchell Family Foundation.
A high-current injector sequence is being developed for use in a flux-coupled stack of high-current cyclotrons for accelerator-driven subcritical (ADS) fission. The design includes an ECR ion source, LEBT, RF quadrupole, and multi-stage chopper. A first cyclotron then accelerates the beams to 100 MeV for injection to the sector isochronous cyclotron. Provisions for control of emittance and bunch tails are described.

TUPPR087

Status of NSCL Cyclotron Gas Stopper

ion, extraction, injection, emittance

2029

N.S. Joshi, G. Bollen, M. Brodeur, D.J. Morrissey, S. Schwarz
NSCL, East Lansing, Michigan, USA

A gas-filled reverse cyclotron for the thermalization of energetic beams is under construction at NSCL/MSU. Rare isotopes produced via projectile fragmentation after in-flight separation will be injected into the device and converted into low-energy beams through buffer gas interactions as they spiral towards the center of the device. The extracted thermal beams will be used for low energy experiments such as precision mass measurements with traps or laser spectroscopy, and further transport for reacceleration. Detailed calculations have been performed to optimize the magnetic field design as well as the transport and stopping of ions inside the gas. An RF-carpet will be used to transport the thermal ions to the axial extraction point. The calculations indicate that the cyclotron gas stopper will be much more efficient for the thermalization of light and medium mass ions compared to linear gas cells. In this contribution we will discuss simulations of the overall performance and acceptance of machine, the beam matching calculations to the fragment separator emittance, and the construction status.

WEPPC063

Superconducting RF Cavity for High-current Cyclotrons

cavity, focusing, extraction, injection

2354

N. Pogue, P.M. McIntyre, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: This work is supported by grants from the State of Texas (ASE) and the Mitchell Family Foundation.
A novel superconducting cavity is presented for applications in cyclotrons. The cavity is in effect an extrusion of a 2-D double-quarter-wave structure, in which the ends of the extrusion are wrapped around and joined so that the cavity has no end perturbations. Power is applied to a linear array of input coupling loops, so that rf sheet current is launched in a laminar flow that matches the power coupled to the orbits of the cyclotron. Each loop is driven by an independent solid-state rf source. A strategy is presented for using to advantage the independent control of phase and amplitude to suppress transient phenomena. Longitudinal modes can be strongly suppressed. These provisions are of importance to suppress phenomena that can limit beam current.

WEPPD066

Design of a Stripline Kicker for Tune Measurement in CSNS RCS

kicker, impedance, lattice, wakefield

2675

X.Y. Yang, S. Fu, T.G. Xu
IHEP, Beijing, People's Republic of China

For CSNS RCS tune measurement, tune value is measured by exciting the bunch with strip-line kicker fed with white noise and using FFT algorithm to the turn-by-turn position of the bunch in the BPM. This article simulates the strip-line kicker in RCS and the efficiency of the kicker is discussed in the MATLAB environment. The parameters of the kicker with arc electrode structure such as wake impedance, thermal state and VSWR are analyzed based on the advantage of this design.

WEPPP011

Multi-Cavity Proton Cyclotron Accelerator: An Electron Counterpart

cavity, proton, electron, acceleration

2744

M.A. LaPointe, S.V. Shchelkunov
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
J.L. Hirshfield
Omega-P, Inc., New Haven, USA
V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Supported by the Department of Energy, Office of Nuclear Physics.
A multi-cavity multi-frequency proton cyclotron accelerator has been proposed. It would utilize cyclotron resonance in each of eight cavities of uniformly diminishing frequency in a uniform magnetic field to comprise a compact (25 m) 1 GeV proton accelerator, according to simulation results*. A four cavity electron counterpart is under construction to test the mechanism of the multi-cavity setup, including phase acceptance, energy gain, and growth of energy spread and emittance for parameters equivalent to the proton case. The four electron counterpart cavities are driven by kW-level phase coherent RF sources at 1.5, 1.8, 2.1 and 2.4 GHz. Each cavity operates in the rotating TE111 mode and includes two feeds in quadrature to drive the rotating mode and two RF pickoffs for diagnostics. The electron beam source is a low-current gun with a BaO cathode which operates at -1200V and <50 microamps. After traversing the cavities, the beam is collected on either a Faraday cup or is imaged with a phosphor screen. Details of the setup and initial results from experiments with the four cavity electron counterpart will be presented.
* M.A. LaPointe, V.P. Yakovlev, S.Yu. Kazakov, and J.L. Hirshfield, Proc. of PAC 2009, May 4-8,Vancouver, BC, Canada, pp.3045-3047 (2011).

THEPPB003

A 1 GeV CW FFAG High Intensity Proton Driver

space-charge, emittance, simulation, focusing

3234

S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
C. Johnstone
Fermilab, Batavia, USA

The drive for high beam power, high duty cycle, and reliable beams at reasonable cost has focused world attention on fixed-field accelerators, notably Fixed-Field Alternating Gradient accelerators (FFAGs). High-intensity GeV proton drivers are of particular interest, as these encounter duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotron. Recently, the concept of isochronous orbits has been explored and developed for non-scaling FFAGs using powerful new methodologies in FFAG accelerator design. These new breeds of FFAGs have been identified by international collaborations for serious study thanks to their potential applications including Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste. The extreme reliability requirements for ADS mandate CW operation capability and the FFAG’s strong focusing, particularly in the vertical, will serve to mitigate the effect of space charge (as compared with the weak-focusing cyclotron). This paper reports on these new advances in FFAG accelerator technology and presents a stable, 0.25-1GeV isochronous FFAG for an accelerator driven subcritical reactor.

THPPC001

Simulation and Design of a 70 MeV Cyclotron RF System

simulation, cavity, vacuum, resonance

3269

G. Gold, R.R. Johnson, B.F. Milton, V. Sabaiduc
BCSI, Vancouver, BC, Canada

The electromagnetic and mechanical design of the resonant cavity for a 70 MeV compact commercial cyclotron has been conducted by Best Cyclotron Systems Inc. Various resonator configurations have been studied for a radial, single-stem design and an optimal solution was selected with excellent electromagnetic properties and minimized construction and operational cost. Rapid model iterations during the design, using CST Microwave Studio and ANSYS, allowed for accurate tuning of geometry to precisely define the shape of the accelerating voltage profile, surface current distribution, and total power loss. The RF system of the BEST 70p cyclotron will operate at the fourth harmonic with two λ/2 separated resonant cavities shielded at the center allowing for beam modulation techniques to be applied through phase modulation of the accelerating voltage.

THPPC056

Development of 12kW RF Power Supply for CYCHU-10 Cyclotron

power-supply, cavity, feedback, impedance

3416

D. Li, T. Hu, J. Huang, K.F. Liu, B. Qin, J. Yang, L. Yang
Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China

One 12kW RF power supply has been developed for CYCHU-10, which is a 10 MeV cyclotron developed in Huazhong University of Science and Technology (HUST). A high performance DDS chip AD9859 is used to synthesize RF signal in this power supply, which is easy to change the output frequency. The centre frequency is 101MHz, and the frequency bandwidth is more than 1MHz. The RF power supply could operate in fine searching mode, coarse searching mode, tracking mode, and so on. It could search the resonant frequency of cavity with the frequency control loop. The final stage amplifier using a triode 3CW20,000H7 operates in grounded grid configuration, which is stable and reliable. The performance test using a 50Ω resistor load has finished, and major results are shown in this paper.

THPPP040

Heavy-ion Beam Acceleration at RIKEN for the Super-Heavy Element Search

ion, target, ion-source, ECR

3823

M. Kase, M. Fujimaki, Y. Higurashi, E. Ikezawa, O. Kamigaito, M. Komiyama, T. Nakagawa, K. Ozeki, N. Sakamoto, K. Suda
RIKEN Nishina Center, Wako, Japan
T. Aihara, T.O. Ohki, K. Oyamada, M. Tamura, A. Uchiyama, H. Yamauchi
SHI Accelerator Service Ltd., Tokyo, Japan

In RIKEN Nishina accelerator center, the experiment on the super-heavy element (Z=113) search has been being carried out since 2003. The RIKEN heavy-ion linac is supplying a heavy-ion beam of 70Zn with energies around 5MeV/nucleon. The beam intensities are required more than 1 particle maicro amper on the target. Very long-term and stable operations are intrinsic for this kind of experiments. So far two events for Z=113 have been found during a net irradiation time of 10345 hours (431 days) with a total dose 1.1 x 10²⁰ (12.8 mg). Heavy operation of the linac will be reported.

THPPP077

Status of the SPES Project: a Neutron Rich ISOL Facility for Re-accelerated RIBs

target, ISOL, neutron, proton

3913

L.A.C. Piazza, A. Andrighetto, G. Bisoffi, P. Favaron, F. Gramegna, A. Lombardi, G.P. Prete, D. Zafiropoulos
INFN/LNL, Legnaro (PD), Italy
L. Calabretta
INFN/LNS, Catania, Italy

SPES (Selective Production of Exotic Species) is an INFN project with the aim to develop a Radioactive Ion Beam (RIB) facility as an intermediate step toward EURISOL. The SPES Project is under realization at the INFN Legnaro National Laboratories site. The SPES Project main goal is to provide a production and accelerator system of exotic beams to perform forefront research in nuclear physics by studying nuclei far from stability. The SPES Project is concentrating on the production of neutron-rich radioactive nuclei with mass in the range 80-160. The final energy of the radioactive beams on target will range from few MeV/u up to 11 MeV/u for A=130. The SPES acceleration system will be presented, together with the facility realization status.

THPPP084

Charge Stripping of Uranium-238 Ion Beam with Helium Gas Stripper

target, ion, acceleration, radiation

3930

H. Imao
RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
N. Fukunishi, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, H. Okuno, T. Watanabe, Y. Watanabe, Y. Yano, S. Yokouchi
RIKEN Nishina Center, Wako, Japan

Development of the reliable and efficient electric charge stripping method is one of the key issues in next-generation high-intensity heavy ion accelerators. Although conventional carbon-foil charge strippers provide a good charge stripping efficiency, two serious problems are emerging; the short usable time and thickness non-uniformity. A charge stripper using low-Z gas is an important candidate applicable for high-intensity 238U beams to replace carbon foil strippers. In the present work, the first actual charge stripping system using helium gas for 238U beams injected at 10.75 MeV/u has been developed and tested.

THPPR053

A CW FFAG for Proton Computed Tomography

proton, extraction, lattice, acceleration

4094

C. Johnstone, D.V. Neuffer
Fermilab, Batavia, USA
H.L. Owen
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P. Snopok
IIT, Chicago, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
An advantage of the cyclotron in proton therapy is the continuous (CW) beam output which reduces complexity and response time in the dosimetry requirements and beam controls. A CW accelerator requires isochronous particle orbits at all energies through the acceleration cycle and present compact isochronous cyclotrons for proton therapy reach only 250 MeV (kinetic energy) which is required for patient treatment, but low for full Proton Computed Tomography (PCT) capability. PCT specifications need 300-330 MeV in order for protons to transit the human body. Recent innovations in nonscaling FFAG design have achieved isochronous performance in a compact (~3 m radius) design at these higher energies. Preliminary isochronous designs are presented here. Lower energy beams can be efficiently extracted for patient treatment without changes to the acceleration cycle and magnet currents.

THPPR063

1 GeV CW Nonscaling FFAG for ADS, and Magnet Parameters

extraction, lattice, simulation, proton

4118

F. Méot, W.-T. Weng
BNL, Upton, Long Island, New York, USA
C. Johnstone
Fermilab, Batavia, USA
P. Snopok
Illinois Institute of Technology, Chicago, IL, USA

Multi-MW proton driver capability remains a challenging, critical technology for many core HEP programs, particularly the neutrino ones such as the Muon Collider and Neutrino factory, and for next generation energy applications such as Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste for nuclear power and waste management. Work is focused almost exclusively on an SRF linac, as, to date, no re-circulating accelerator can attain the 10^-20 MW capability necessary for the nuclear applications. Recently, the concept of isochronous orbits has been explored and developed for nonscaling FFAGs using powerful new methodologies in FFAG accelerator design. The FFAG can remain isochronous beyond the energy reach of cyclotrons and with fixed magnetic fields and strong focusing coupled to recent advances in tune stability, dynamic aperture, and footprint, serious study is underway on a potential application to the ADS problem. Work is progressing on a stable, high intensity, 0.25-1GeV isochronous FFAG. Development and studies of novel magnets with the nonlinear radial fields required to support isochronous operation are reported here.

THPPR064

MW-class 800 MeV/n H²⁺ SC-Cyclotron for ADC application, Design Study and Goals

extraction, injection, target, closed-orbit

4121

F. Méot, T. Roser, W.-T. Weng
BNL, Upton, Long Island, New York, USA
L. Calabretta
INFN/LNS, Catania, Italy
A. Calanna
CSFNSM, Catania, Italy

A megawatt class isochronous cyclotron is a potential candidate for accelerator driven systems, as in the subcritical-fission molten-salt reactor application. A scheme for a 800 MeV/nucleon cyclotron accelerating molecular H₂⁺ has been derived from on-going proton driver design studies for neutrino beam production. The present paper reports on beam dynamics studies regarding that cyclotron, exploiting its superconducting coil magnetic sector OPERA field map. These studies are aimed at assessing lattice properties as accelerated orbit, phase oscillations, tunes, beam envelopes and other resonance effects.

THPPR073

Target Studies for the Production of Lithium 8 for Neutrino Physics Using a Low Energy Cyclotron

target, neutron, proton, simulation

4145

A. Bungau, R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom
J.M. Conrad, J. Spitz
MIT, Cambridge, Massachusetts, USA
M. Shaevitz
Columbia University, New York, USA

Lithium 8 is a short lived beta emitter producing a high energy anti-neutrino, which is very suitable for making several measurements of fundamental quantities. It is proposed to produce Lithium 8 with a commercially available 60 MeV cyclotron using protons or alpha particles on a Beryllium 9 target. We have used the GEANT4 program to model these processes, and calculate the antineutrino fluxes that could be obtained in a practical system. We also calculate the production of undesirable contaminants such as Boron 8, and show that these can be reduced to a very low level.

THPPR076

Optimising Neutron Production From Compact Low Energy Accelerators

target, neutron, proton, simulation

4154

N. Ratcliffe, R.J. Barlow, A. Bungau, R. Cywinski
University of Huddersfield, Huddersfield, United Kingdom
T.R. Edgecock
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

There is currently much development in accelerator based methods to provide flexible and reliable neutron generators, in response to a decline in the availability of nuclear reactors. In this paper the focus is on neutron production via a low energy DC proton accelerator (1-10 MeV) and light target system. GEANT4 simulations are being used to study various aspects of target design, beginning with studies into light targets, such as lithium and beryllium, which are already in use. Initially the aim is to replicate these designs and benchmark these simulations, with other models and experimental results, before investigating how modifications can improve neutron production and tailor experimental geometries to specific applications such as neutron capture therapy and medical isotope production.