Cyclotrons2013 - List of Keywords (simulation)

Paper	Title	Other Keywords	Page
MOPPT030	Past, Present and Future Activities for Radiation Effects Testing at JULIC/COSY	proton, radiation, neutron, ion	88
	S.K. Hoeffgen, S. Metzger FhG, Euskirchen, Germany R. Brings, O. Felden, R. Gebel, R. Maier, D. Prasuhn FZJ, Jülich, Germany M. Brugger, R. Garcia Alia CERN, Geneva, Switzerland
	The testing of radiation effects (displacement damage DD, single event effects SEE) with energetic protons for electronics used in space and accelerators is of growing importance. Setup and past experience of a dedicated test stand used by Fraunhofer INT at the JULIC cyclotron will be presented. For general DD testing and for testing SEE of the trapped protons in space, the energy of 35 MeV of the JULIC Cyclotron is usually sufficient. During solar proton events, as well as at high energy accelerators (CERN, FAIR), electronics are confronted with protons of much higher energy. Recent scientific studies have shown that for single event upsets* as well as destructive failures (e.g, single event latch-ups)** a cross section measured at energies in the tens oF one/two-hundred MeV range (e.g. PIF@PSI) can significantly underestimate the failure rate. To avoid unnecessary high safety margins there is a growing need for the opportunity to test electronics at several GeV, like the beam provided by the Cooler-Synchrotron COSY in Jülich. R. Garcia Alia et. al., accepted for publication, IEEE TNS (2013), DOI:10.1109/TNS.2013.2249096 *J. R. Schwank et al., IEEE TNS, vol. 52, pp2622 (2005)

MO3PB01	An Inverse Cyclotron for Muon Cooling	extraction, cyclotron, focusing, injection	97
	T.L. Hart, D.J. Summers UMiss, University, Mississippi, USA
	The production of intense high energy muon beams for muon colliders is an active area of interest due to the muon's large mass and pointlike structure. The muon production and the subsequent preparation into a beam are challenging due to the large emittance of the initial beam and the short muon lifetime. Most muon cooling channels being developed are single-pass structures due to the difficulty of injecting large emittance beams into a circular device. Inverse cyclotrons can potentially solve the injection problem using single turn energy loss injection and also reduce the muon beam emittance by a large factor. An end-to-end simulation of an inverse cyclotron for muon cooling is presented performed with G4Beamline, a GEANT-based particle tracking simulation program. Muons are collected in a central trap and then all ejected together.
	Slides MO3PB01 [1.747 MB]

MO3PB03	High Gradient Superconducting Cavity Development for FFAG	cavity, proton, extraction, injection	105
	S.V. Kutsaev, Z.A. Conway, P.N. Ostroumov ANL, Argonne, USA R.D. Ford, C. Johnstone PAC, Batavia, Illinois, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 Like the cyclotron, the Fixed Field Alternating Gradient machine (FFAG) is a compact accelerator with variety of applications in industry and medicine. High intensity, fixed-field compact accelerators require enhanced orbit separation to minimize beam losses especially at extraction. In medium energy and compact FFAGs, this requires a total voltage of ~20 MV per turn with continuous wave accelerating gradients of ~10MV/m, which can only be achieved using superconducting accelerating cavities. This high voltage can be generated using 4 superconducting (SC) cavities operating at higher harmonics of the beam revolution, equal to approximately 200 MHz. The cavities and cryomodule are inserted into a 2m straight section of a racetrack-shaped FFAG. However, as with cyclotrons, the FFAG has a large horizontal acceleration aperture presenting a challenging problem for SCRF cavity design. In this work, we present SC cavity design with 50 cm x 1 cm beam apertures, their electrodynamics optimization, and multiphysics analysis. To achieve a 1 mA average beam current, each cavity is powered by two 100 kW RF couplers.
	Slides MO3PB03 [2.819 MB]

TU2PB01	A Study of Multipacting Effects in Large Cyclotron Cavities by Means of Fully 3-Dimensional Simulations	electron, cavity, cyclotron, RF-structure	142
	C. Wang, B. Ji, Y. Lei, P.Z. Li, J.S. Xing, Z.G. Yin, T.J. Zhang CIAE, Beijing, People's Republic of China A. Adelmann, A. Gsell, M. Seidel PSI, Villigen PSI, Switzerland
	The field emission model and the secondary emission model, as well as 3D boundary geometry handling capabilities, are needed to efficiently and precisely simulate multipacting phenomena. These models have been implemented in OPAL, a parallel framework for charged particle optics in accelerator structures and beam lines. The models and their implementation are carefully benchmarked against a non-stationary multipacting theory. A dedicated multipacting experiment with nanosecond time resolution for the classic parallel plate geometry has also successfully shown the validity of OPAL model. Multipacting phenomena, in the CYCIAE-100 cyclotron, under construction at China Institute of Atomic Energy, are expected to be more severe during the RF conditioning process than in separate-sector cyclotrons. This is because the magnetic fields in the valley are stronger, which may make the impact electrons easier to reach energies that lead to larger multipacting probabilities. We report on simulation results for CYCIAE-100, which gives us an insight view of the multipacting process and help to develop cures to suppress these phenomena.
	Slides TU2PB01 [7.012 MB]

TU2PB03	Heat Transfer Study and Cooling of 10 MeV Cyclotron Cavity	cavity, cyclotron, factory, ion	150
	S. Saboonchi, H. Afarideh AUT, Tehran, Iran M.R. Asadi PPRC, Tehran, Iran J.-S. Chai, M. Ghergherehchi SKKU, Suwon, Republic of Korea
	The most important problem in mechanical design of RF cavity of cyclotron is generated heat by RF power loss. An optimized cooling system for cavity is necessary to prevent Dee damaging and minimizing error function of cyclotron created by displacements. Also optimization of water circuit and water flow is essential because it affects unwanted vibrations and manufacturing. In this paper an attempt has been done to design an optimized cooling system for the cavity of a 10 MeV cyclotron with frequency of 69 MHz and 50 KW RF power using ANSYS and CST software.

TU2PB04	Resonator System for the BEST 70 MeV Cyclotron	controls, cyclotron, LLRF, cavity	153
	V. Sabaiduc, G. Gold, B.A. Versteeg BCSI, Vancouver, Canada J. Panama Best Theratronics Ltd., Ottawa, Ontario, Canada
	Best Cyclotron Systems Inc. is presently developing a 70 MeV cyclotron for radioisotope production and research purpose. The RF system comprises two separated resonators driven by independent amplifiers to allow for the phase and amplitude modulation technique to be applied for beam intensity modulation. The resonators are presently in the commissioning phase consisting of cold test measurements followed by high power commissioning in the cyclotron. Preliminary simulation results have been reported and are: 56MHz operation (fourth harmonic, half-wave resonator design), 60 to 70kV dee voltage, quality factor 8000 with the estimated dissipated power of 17kW per resonator. The electromagnetic modeling has been done with CST Microwave Studio. All simulation results showed a very conservative design with typical parameters for the energy and size of the resonators. The paper will present the measurement results on a cold test set-up configuration as well as the commissioning with high power in the cyclotron.
	Slides TU2PB04 [4.920 MB]

TUPPT023	Design and Simulation of Cavity for 10 MeV Compact Cyclotron	cavity, cyclotron, coupling, acceleration	200
	V. Afzalan, H. Afarideh, R. Azizi AUT, Tehran, Iran J.-S. Chai, M. Ghergherehchi SKKU, Suwon, Republic of Korea
	RF system is known as one of the most vital parts to produce the efficient accelerator system. In this paper, the RF system and cavity of 10 MeV AVF ( Azimuthally Varying Field ) Cyclotron for radioisotope production are designed. The Cyclotron works on 4th harmonic with Dee's voltage of 50 KV. In order to supply the expected accelerating voltages RF power coupling and RF tuner has been considered. The RF system is simulated using commercially available simulator, CST Microwave Studio code. In contrast the geometry of cavity is optimized to achieve suitable Q value in desired frequency. Since the factors are non-ideal during the fabrication process, the actual Q value of cavities is estimated.

TUPPT025	Resonator System for the BCSI Test Stand Cyclotron	cyclotron, cavity, controls, LLRF	206
	G. Gold, V. Sabaiduc, J. Zhu BCSI, Vancouver, Canada J. Panama Best Theratronics Ltd., Ottawa, Ontario, Canada L. AC. Piazza INFN/LNL, Legnaro (PD), Italy
	Best Cyclotron Systems Inc. is presently developing a test facility for beam injection into a center region cyclotron operating at maximum 1MeV. The test stand cyclotron will operate at various fixed frequencies that will cover the entire range from 49MHz to 80MHz as estimated for the current cyclotron models under development at BCSI. The resonator was designed with a variable coaxial section allowing for the frequency to be continuously adjusted as required for the particular model in study. Having interchangeable dee tip geometries presented various thermal management challenges which have been addressed. Three operational frequencies, 49MHz, 56MHz and 73MHz have been simulated with CST Microwave Studio. The paper will report the theoretical parameters of the cavity, mechanical design considerations and resonator commissioning on the first operational frequency of 49MHz.

TUPPT029	Design Study of a 83.2 MHz RF Cavity for the 9 MeV Compact Cyclotron	cavity, cyclotron, ion, impedance	215
	S. Shin, J.-S. Chai, J.C. Lee SKKU, Suwon, Republic of Korea B.N. Lee KAERI, Daejon, Republic of Korea
	Funding: National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (2010-0025953) A compact cyclotron accelerating H⁻ ion for producing a radioactive isotope FDG (FluoroDeoxyGlucose) for PET (Positron Emission Tomography) has been designed at Sungkyunkwan University. The H⁻ ion which generated from the PIG (Panning Ion Gauge) ion source will be accelerated at the normal conducting RF cavity which uses 83.2 MHz of resonance frequency and extracted at the carbon foil striper at the energy of 9 MeV. This cyclotron has to be small to install local hospital while FDG production needs more than 9 MeV of proton beam energy. Chasing two hare at once, deep valley type of magnet has been selected for high energy and compact cyclotron. Due to the small size of valley space where RF cavities will be installed, lots of difficulties have been introduced. Despite of those difficulties at the designing process, we could achieve resonance frequency of 83.2 MHz and Q-factor of 4500 with very compact size of RF cavity.

TUPSH002	Design and Construction of Combination Magnet for CYCIAE-100	proton, cyclotron, extraction, status	221
	S.M. Wei, Shizhong. An, M. Li, C. Wang, M. Yin, T.J. Zhang, X. Zheng CIAE, Beijing, People's Republic of China
	The high intensity compact cyclotron CYCIAE-100 being constructed at China Institue of Atomic Energy (CIAE) is designed to extract proton beam from 75MeV to 100MeV in two opposite directions by stripping foil. Two combination magnets have been designed to bend the proton beams with different energies into one common beam line. The combination magnets have been designed into the return yoke of the main magnet of CYCIAE-100 for the dynamic reason. 2 D and 3D simulation of these combination magnets has been finished, the machining of them has also been finished. The magnetic field of the combination magnets has been measured and the results show that the measurements are very closed to the calculation, indicating these two magnets can be used in the BRIF project.

TUPSH007	Improvement in Design of 10 MeV AVF Cyclotron Magnet	betatron, cyclotron, factory, magnet-design	233
	R. Solhju, H. Afarideh, B. Mahdian AUT, Tehran, Iran J.-S. Chai, M. Ghergherehchi SKKU, Suwon, Republic of Korea
	Design study of a 10 MeV baby cyclotron which accelerates H− ions is started in March, 2012 at Amirkabir University of Technology (AUT). Up to this point, conceptual design of the cyclotron magnet is finished. This process has been done in two steps: initial design and then optimization. After finishing the initial design of the magnet by CST software and adopting hard-edge approximation for finding the pole tip, an optimization process has been followed to smooth the pole edge in order to decrease the tension in sharp edges of the pole. In this paper, we are going to explain about the optimization process in details. Actually, we tried to fit the best curve at the pole edges of the magnet with goal of having minimum magnetic field error. Also a short report of results which was obtained before optimization is provided here. Precision of this design is ensured by checking the magnetic field and beam dynamic parameters during the optimization.

TUPSH008	Conceptual Design of the 100 MeV Separated Sector Cyclotron	cyclotron, resonance, extraction, magnet-design	236
	B. Mahdian, H. Afarideh, R. Solhju AUT, Tehran, Iran J.-S. Chai, M. Ghergherehchi SKKU, Suwon, Republic of Korea
	The 100 MeV separated sector cyclotron was designed at Amirkabir University of Technology (AUT), which was aimed for various applications including radioactive ion-beam (RIB) production and proton therapy. It has four separated sector magnets. The cyclotron magnet design was based on an iterative process starting from a simple model that requires the vision of the complete cyclotron and the possibility of integration of all subsystems. By computer simulation with the 3D (CST) and 2D (POSSION) codes, principle parameters of the cyclotron magnet system were estimated (pole radius 180 cm, outer diameter 640 cm, height 300 cm). The results showed that the isochronous deviations between simulated values and the calculation one are smaller than 5 Gauss at most radii and therefore fulfilled the requirements. This work has been done with high accuracy which is proved by particle trajectories and considered mesh range. It has been concluded that it can be possible to design and develop this high energy cyclotron by introducing simple model without using trim and harmonic coils.

TUPSH013	Design Study of 10 MeV H⁻ Cyclotron Magnet	cyclotron, magnet-design, radio-frequency, extraction	248
	H.S. Kim, J.-S. Chai, M. Ghergherehchi, H.W. Kim, S.H. Kim, S.H. Lee SKKU, Suwon, Republic of Korea
	Funding: This work has been supported by National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning (NRF-2010-0025952). For the past decades, PET (positron emission tomography) has been remarkable growth in market. PET using 18F is widely provided for cancer screening and expected to be installed at small and medium hospital for convenience of patients. At Sungkyunkwan University, 10 MeV H⁻ cyclotron, which produces 18F is being developed. In this paper, we demonstrated main magnet design and whole design procedure was explained. The result of design is verified by orbit analysis and single particle tracking. The description of the obtained result is presented in this paper.

TU3PB01	Bunch-Shape Measurements at PSI’s High-power Cyclotrons and Proton Beam Lines	proton, cyclotron, electron, cathode	257
	R. Dölling PSI, Villigen PSI, Switzerland
	Longitudinal-transversal 2D-density distributions of the bunched 2.2 mA CW proton beam can now be measured at the 13 last turns of the Injector 2 cyclotron, at several locations in the connecting beam line to the Ring cyclotron, at the first two turns of the Ring cyclotron (all at energies around 72 MeV), as well as behind the Ring cyclotron (at 590 MeV). In the large part, distributions can be taken from several angles of view, separated each by 45°. The measurement systems at our facility have evolved with time; this paper gives the present status, performance, limits and typical results. Due to the limited space, we refer in the large part to our previous publications [1, 2, 3] and concentrate on recent findings and measurements and ideas for next steps.
	Slides TU3PB01 [9.393 MB]

TU3PB04	TRIUMF Extraction Foil Developments and Contamination Reduction	electron, extraction, scattering, TRIUMF	269
	Y.-N. Rao, R.A. Baartman, I.V. Bylinskii, V.A. Verzilov TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada J.M. Schippers PSI, Villigen PSI, Switzerland
	Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada. We made important developments on the extraction probes and stripping foils at TRIUMF. One of the issues we had was the ⁷Be contamination being observed near the 1A stripper, and relatedly, stripping foils warped or even broke during use. This was deemed due to over-heating in the foil and the frame. Another issue was related to the beam spills. Beam spills are primarily caused by the large angle scattering from the stripping foil. It was thus suggested that thinner foils be used to minimize the scattering. In view of these 2 issues, improvements were made such that (1) highly-orientated pyrolytic graphite foils, of thickness around 2 mg/cm², are now used; (2) Tantalum frame is now used in place of the previous stainless steel. These changes, plus additional heat relief features introduced, have resulted in 4 times longer lifetime with the foil, and 5 to 10 times reduction to the tank contamination level around the extraction probe. Also, these improvements have led to significantly reduced amount of beam spill monitor trips. This paper presents these developments and outcomes, including the simulations and calculations performed.
	Slides TU3PB04 [4.798 MB]

WE1PB02	The Rutgers Cyclotron: Placing Student's Careers on Target	cyclotron, focusing, ion, proton	291
	K.J. Ruisard Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA G.A. Hine, T.W. Koeth UMD, College Park, Maryland, USA A.J. Rosenberg Stanford University, Stanford, California, USA
	The Rutgers 12” Cyclotron is an educational tool used to introduce students to the multifaceted field of accelerator physics. Since its inception, the cyclotron has been under continuous development and is currently incorporated into the modern physics lab course at Rutgers University, as a semester-long mentored project. Students who participate in the cyclotron project receive an introduction to topics such as beam physics, high voltage power, RF systems, vacuum systems and magnet operation. Student projects have led to three different focusing pole geometries, including, most recently, a spiral edged azimuthally varying field (AVF) configuration. The Rutgers Cyclotron is often a student’s first encounter with an accelerator, and has inspired careers in accelerator physics.
	Slides WE1PB02 [14.090 MB]

WE1PB04	A Novel Optical Method for Measuring Beam Phase and Width in the Rutgers 12-Inch Cyclotron	cyclotron, ion, focusing, proton	299
	J.L. Gonski, S. Burcher, T.W. Koeth, J.E. Krutzler, S. Lazarov Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA J. Beaudoin UMD, College Park, Maryland, USA
	We present an experimental longitudinal measurement of beam and phase slippage as a function of magnetic field deviation in a weak focusing field, using proton acceleration data from the Rutgers 12-inch cyclotron. A gated camera was used to determine beam arrival time from the radiation emitted by a fast ZnO:Ga doped phosphor target when struck by accelerated protons. Images integrated light emitted in 9 degree increments over a full 360-degree RF cycle. Analysis of relative image brightness allowed for the successful acquisition of relative phase shift and azimuthal beam width over several magnetic field strengths. Theoretical predictions and simulation via Poisson Superfish and SIMION software show good agreement with data, validating the optical method for qualitative measurements. This new method is independent of dee voltage and allows for measurements to be taken in the central region of the cyclotron, where other electrically based methods of measurement are challenging due to high RF electric fields. Such characteristics validate the use of gated camera imaging for cyclotron research, and motivate future refinement of this technique for a variety of studies.
	Slides WE1PB04 [3.662 MB]

WE2PB02	Vlasov Equation Approach to Space Charge Effects in Isochronous Machines	space-charge, cyclotron, betatron, plasma	310
	A.J. Cerfon, O. Bühler, J.V. Guadagni Courant Institute of Mathematical Sciences, New York University, New York, USA J.P. Freidberg, F.I. Parra Diaz MIT/PSFC, Cambridge, Massachusetts, USA
	Starting from the collisionless Vlasov equation, we derive two simple coupled two-dimensional fluid equations describing the radial-longitudinal beam vortex motion associated with space charge effects in isochronous cyclotrons. These equations show that the vortex motion can be intuitively understood as the nonlinear advection of the beam by the ExB velocity field, where E is the electric field due to the space charge and B is the applied magnetic field. This explains why elongated beams develop spiral halos while round beams are always stable. Solving the coupled equations numerically, we find good agreement between our model and 3-D Particle-In-Cell OPAL simulations. J.J. Yang, A.Adelmann, M. Humbel, M. Seidel, and T.J. Zhang, Physical Review Special Topics Accelerators and Beams 13, 062401 (2010)
	Slides WE2PB02 [1.166 MB]

WE2PB03	Transverse-Longitudinal Coupling by Space Charge in Cyclotrons	emittance, space-charge, cyclotron, focusing	315
	C. Baumgarten PSI, Villigen PSI, Switzerland
	Based on a linear space charge model and on the results of PIC-simulations with OPAL, we analyze the conditions under which space charge forces support bunch compactness in high intensity cyclotrons and/or FFAGs. For this purpose we compare the simulated emittance increase and halo formation for different matched and mismatched particle distributions injected into a separate sector cyclotron with different phase curves.
	Slides WE2PB03 [3.187 MB]

WEPPT009	Transverse Phase-Space Distributions of Low Energy Ion Beams Extracted from an ECR Ion Source	ion, ion-source, emittance, extraction	341
	S. Saminathan TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada J.P.M. Beijers, S. Brandenburg, H.R. Kremers, V. Mironov KVI, Groningen, The Netherlands
	Transverse phase-space distributions of low-energy ion beams extracted from ECR ion sources often show higher-order effects caused by ion-optical aberrations. Understanding these effects is mandatory to keep emittance growth and the resulting beam losses in low-energy beam transport lines under control. We present the results of an experimental and theoretical study of beam extraction and transport in the AGOR injection line at KVI. Particle tracking simulations have been performed of a multi-component neon ion beam extracted from an ECR ion source to calculate 4D phase-space distributions at various positions along the beamline. The simulations compare well with beam profile and emittance measurements.

WEPPT012	Beam Dynamics in Presence of Imperfection Fields Near the Extraction Zone of Kolkata Superconducting Cyclotron	extraction, cyclotron, resonance, betatron	347
	J. Debnath, U. Bhunia, A. Chakrabarti, M.K. Dey, A. Dutta, Z.A. Naser, S. Paul, J. Pradhan, V. Singh VECC, Kolkata, India
	Funding: VECC, DAE The superconducting cyclotron at Kolkata has accelerated the ion beams up to the extraction radius producing neutrons via nuclear reactions. After that the beam extraction process has been tried exhaustively. But rigorous beam extraction trials indicate towards some kind of error field, which was not possible to balance with the trim coil operated in harmonic-coil mode. It is found that the beam is being off-centered by a large amount after crossing the resonance zone and it is not reaching the extraction radius in proper path. This paper will be emphasizing the effect of various kind of error field on the beam. However, the magnetic field is being measured again to know the exact distribution of the field.

WEPPT014	Analysis of Phase Bunching in the Central Region of the JAEA AVF Cyclotron	acceleration, bunching, cyclotron, ion	350
	N. Miyawaki, H. Kashiwagi, S. Kurashima, S. Okumura JAEA/TARRI, Gunma-ken, Japan M. Fukuda RCNP, Osaka, Japan
	Phase bunching generated in the central region of an AVF cyclotron was estimated by a simplified geometric trajectory analysis model for particles traveling from the first to the second acceleration gap. In principle, a rising slope of a dee-voltage at the first acceleration gap is more or less effective for production of the phase bunching. The phase difference between particles at the second acceleration gap depends on combination of four parameters: the acceleration harmonic number (h), a span angle of the dee electrode, a span angle from the first to the second acceleration gap, a ratio between a peak dee-voltage and an extraction voltage of an ion source. In the case of the JAEA AVF cyclotron, the effective phase bunching was realized for h = 2 and 3, and the geometric condition of phase bunching was unrealistic for h = 1. An orbit simulation for the JAEA AVF cyclotron indicated that the initial beam phase width of 40 RF degrees for h = 2 was compressed to 11 RF degrees. The phase bunching evaluation based on the simplified geometric trajectory analysis was consistent with the orbit simulation result, and practical phase bunching was verified by beam phase width measurement.

WEPPT018	Behavior of Space Charge Dominated Beam Envelope in Central Region of High Current Cyclotron	space-charge, acceleration, injection, cyclotron	359
	R. Azizi, H. Afarideh, V. Afzalan AUT, Tehran, Iran J.-S. Chai, M. Ghergherehchi SKKU, Suwon, Republic of Korea
	In this paper the space charge effect in the two first turn after injection has been investigated. In order to determine beam envelopes, two corresponding equations were chosen. In addition, all steps of calculation were done by MATLAB program. It should be mentioned limiting current and also magnetic, electrical field and edge effect has been considered. As far as, the high current cyclotron with 0.8π mm mrad emittance has been studied and current alters till 10 mA.* *M. Reiser, Theory and Design of Charged Particle Beams (Wiley, New York, 1994), Chapters.3 and 4.

WEPPT019	Investigation on the Transverse Emittance Growth of Intense Beam during Bunching	bunching, emittance, space-charge, solenoid	361
	P. Sing Babu, A. Goswami, V.S. Pandit VECC, Kolkata, India
	Bunchers are widely used in the injection system of cyclotrons to transform dc beam into a bunched beam in a desired phase width. In the case of low beam current, the longitudinal compression of beam has very little effect on the transverse dynamics. However in the case of high current bunching the increase of current in the specified bunch width as the beam advances affects the transverse behavior. A 2D particle-in-cell code has been developed to study the transverse dynamics during beam bunching in the injection system of 10MeV, 5mA compact proton cyclotron. We have used a linear increase of beam current in the specified bunch width from the buncher position to the time focus. In the PIC method this effect is introduced by reweighting the charge and mass of the macroparticles during the transport with longitudinal compression. The evolutions of beam envelope and emittance growth have been estimated for various initial particle distributions. It is observed that the rms beam size is independent of particular beam distribution whereas rms emittance grows with nonuniformity of the distribution and peaks near the time focus.

WEPPT027	Design of the Injection into the 800 MeV/amu High Power Cyclotron	injection, cyclotron, closed-orbit, septum	375
	M. Haj Tahar, F. Méot BNL, Upton, Long Island, New York, USA L. Calabretta INFN/LNS, Catania, Italy A. Calanna CSFNSM, Catania, Italy
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. We present the design of the injection line into a separated sector cyclotron (SSC) aimed at the production of a high power beam of 800MeV/amu molecular H²⁺ for ADS-Reactor applications. To work out the beam line parameters and beam dynamics simulations, including the first accelerated turns, we used the ray-tracing code Zgoubi and the OPERA magnetic field map of the cyclotron sector. We simulated the injection path of the H²⁺ and evaluated both radial and vertical injection schemes in order to evaluate the parameters so derived. The paper details and discusses various aspects of that design study and its outcomes. A.Calanna et al., A multi-megawatt ring cyclotron to search for CP violation in the neutrino sector, April 2011, e-Print: arXiv:1104.4985

WEPPT029	The Cyclotron Complex for the DAEδALUS Experiment	cyclotron, injection, acceleration, extraction	381
	A. Calanna, D. Campo, J.M. Conrad MIT, Cambridge, Massachusetts, USA L. Calabretta INFN/LNS, Catania, Italy M. Haj Tahar, F. Méot BNL, Upton, Long Island, New York, USA
	The cyclotron complex for the DAEδALUS CP-Violation neutrino experiment consists of a compact cyclotron able to accelerate high-current (5 electrical milliamp) H²⁺ beams up to an energy of 60 MeV/amu, cleanly extract this beam with a conventional septum arrangement, and transport it to a superconducting ring cyclotron able to accelerate the beam up to 800 MeV/amu. H²⁺ is dissociated with thin stripping foils for efficient extraction as protons for transport to a megawatt-class target for neutrino production. The injection cyclotron will be similar to the one proposed for the IsoDAR experiment (Paper WEPPT029). The Ring cyclotron is similar in size and engineering concept to the SRC at RIKEN. Space-charge dominated beam dynamics simulations using OPAL have been performed for an 8-sector geometry, and indicate acceptable transmission and low beam losses. Subsequent engineering magnet-design studies of Minervini et al. point to a 6-sector configuration as more practical. Recalculation of the beam dynamics for this new configuration will be performed in the coming year. Results of the studies conducted to date will be presented.

WE3PB01	Experimental Study of Resonance Crossing with a Paul Trap	resonance, emittance, ion, plasma	409
	H. Sugimoto KEK, Ibaraki, Japan
	The effect of resonance crossing on beam stability is studied systematically by employing a novel tabletop experimental tool and a multiparticle simulation code. A large number of ions are confined in a compact linear Paul trap to reproduce the collective beam behavior. We can prove that the ion plasma in the trap is physically equivalent to a charged-particle beam propagating through a strong focusing channel. The plasma confinement force is quickly ramped such that the trap operating point traverses linear and nonlinear resonance stop bands as in cyclotrons and FFAGs.
	Slides WE3PB01 [9.757 MB]

WE4PB01	Tracking in a Cyclotron with Geant4	TRIUMF, cyclotron, proton, acceleration	423
	F.W. Jones, T. Planche, Y.-N. Rao TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Building on its precursor GEANT, the tracking and simulation toolkit Geant4 has been conceived and realised in a very general fashion, with much attention given to the modeling of electric and magnetic fields and the accuracy of tracking charged particles through them. As evidenced by the G4Beamline application, Geant4 offers a unique simulation approach to beam lines and accelerators, in a 3D geometry and without some of the limitations posed by conventional optics and tracking codes. Here we apply G4Beamline to the TRIUMF cyclotron, describing the generation and input of the field data, accuracy of closed orbits, stability of multi-turn tracking, tracking accelerated orbits, and phase acceptance. Geant4's 3D visualization tools allow detailed examination of trajectories as well as a particle's-eye view of the acceleration process.
	Slides WE4PB01 [4.146 MB]

WE4PB02	An All-Purpose Accelerator Code, Zgoubi	radiation, damping, polarization, synchrotron	426
	F. Méot BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The ray-tracing code Zgoubi* has long been 6D-tracking through all possible types of fixed field rings*, including, recently, 6D transmission from injection-up to extraction-down in high power cyclotrons in the frame of ADS-Reactor R/D. This is to be added to the long exploited many other capabilities of the code as spin transport, in-flight decay, synchrotron radiation energy loss, etc. An overview will be given, including recent space-charge developments, with illustration including recent high power cyclotron applications. http://sourceforge.net/projects/zgoubi/, http://www.osti.gov/bridge/basicsearch.jsp **6-D beam dynamics simulations in FFAGs, F. Meot, ICFA Beam Dyn. Newslett.43:44-50 (2007)
	Slides WE4PB02 [4.414 MB]

TH2PB04	A Multi-Leaf Faraday Cup Especially for Proton Therapy of Ocular Tumors	proton, radiation, cyclotron, ion	458
	C.S.G. Kunert, J. Bundesmann, T. Damerow, A. Denker HZB, Berlin, Germany A. Weber Charite, Berlin, Germany
	The Helmholtz-Zentrum Berlin (HZB) provides together with the University Hospital Charité in Berlin a treatment of eye tumors with a proton beam. The 68 MeV proton beam is delivered by an isochronous cyclotron as main accelerator. In tumor irradiation treatment the positioning of the radiation field is very important. In eye tumor treatment it is even more important, due to the small and sensitive structures in the eye. Hence, due to the well defined Bragg peak, a proton beam is a good choice to achieve rather small fields of dose delivery. Again, due to the small structures in the eye, one needs to know the proton beam energy and the proton beam range with a high accuracy. One possible solution for a quick and high precision measurement of the range of such proton beams is a Multi-Leaf Faraday Cup (MLFC). This work has the task to develop such a MLFC concerning the special requirements of the eye tumor therapy. In this presentation an overview of the progress of this work will be given, regarding the MLFC principles and issues such as the first technical realization.
	Slides TH2PB04 [5.358 MB]

Paper

Title

Other Keywords

Page

MOPPT030

Past, Present and Future Activities for Radiation Effects Testing at JULIC/COSY

proton, radiation, neutron, ion

88

S.K. Hoeffgen, S. Metzger
FhG, Euskirchen, Germany
R. Brings, O. Felden, R. Gebel, R. Maier, D. Prasuhn
FZJ, Jülich, Germany
M. Brugger, R. Garcia Alia
CERN, Geneva, Switzerland

The testing of radiation effects (displacement damage DD, single event effects SEE) with energetic protons for electronics used in space and accelerators is of growing importance. Setup and past experience of a dedicated test stand used by Fraunhofer INT at the JULIC cyclotron will be presented. For general DD testing and for testing SEE of the trapped protons in space, the energy of 35 MeV of the JULIC Cyclotron is usually sufficient. During solar proton events, as well as at high energy accelerators (CERN, FAIR), electronics are confronted with protons of much higher energy. Recent scientific studies have shown that for single event upsets* as well as destructive failures (e.g, single event latch-ups)** a cross section measured at energies in the tens oF one/two-hundred MeV range (e.g. PIF@PSI) can significantly underestimate the failure rate. To avoid unnecessary high safety margins there is a growing need for the opportunity to test electronics at several GeV, like the beam provided by the Cooler-Synchrotron COSY in Jülich.
*R. Garcia Alia et. al., accepted for publication, IEEE TNS (2013), DOI:10.1109/TNS.2013.2249096
**J. R. Schwank et al., IEEE TNS, vol. 52, pp2622 (2005)

MO3PB01

An Inverse Cyclotron for Muon Cooling

extraction, cyclotron, focusing, injection

97

T.L. Hart, D.J. Summers
UMiss, University, Mississippi, USA

The production of intense high energy muon beams for muon colliders is an active area of interest due to the muon's large mass and pointlike structure. The muon production and the subsequent preparation into a beam are challenging due to the large emittance of the initial beam and the short muon lifetime. Most muon cooling channels being developed are single-pass structures due to the difficulty of injecting large emittance beams into a circular device. Inverse cyclotrons can potentially solve the injection problem using single turn energy loss injection and also reduce the muon beam emittance by a large factor. An end-to-end simulation of an inverse cyclotron for muon cooling is presented performed with G4Beamline, a GEANT-based particle tracking simulation program. Muons are collected in a central trap and then all ejected together.

Slides MO3PB01 [1.747 MB]

MO3PB03

High Gradient Superconducting Cavity Development for FFAG

cavity, proton, extraction, injection

105

S.V. Kutsaev, Z.A. Conway, P.N. Ostroumov
ANL, Argonne, USA
R.D. Ford, C. Johnstone
PAC, Batavia, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357
Like the cyclotron, the Fixed Field Alternating Gradient machine (FFAG) is a compact accelerator with variety of applications in industry and medicine. High intensity, fixed-field compact accelerators require enhanced orbit separation to minimize beam losses especially at extraction. In medium energy and compact FFAGs, this requires a total voltage of ~20 MV per turn with continuous wave accelerating gradients of ~10MV/m, which can only be achieved using superconducting accelerating cavities. This high voltage can be generated using 4 superconducting (SC) cavities operating at higher harmonics of the beam revolution, equal to approximately 200 MHz. The cavities and cryomodule are inserted into a 2m straight section of a racetrack-shaped FFAG. However, as with cyclotrons, the FFAG has a large horizontal acceleration aperture presenting a challenging problem for SCRF cavity design. In this work, we present SC cavity design with 50 cm x 1 cm beam apertures, their electrodynamics optimization, and multiphysics analysis. To achieve a 1 mA average beam current, each cavity is powered by two 100 kW RF couplers.

Slides MO3PB03 [2.819 MB]

TU2PB01

A Study of Multipacting Effects in Large Cyclotron Cavities by Means of Fully 3-Dimensional Simulations

electron, cavity, cyclotron, RF-structure

142

C. Wang, B. Ji, Y. Lei, P.Z. Li, J.S. Xing, Z.G. Yin, T.J. Zhang
CIAE, Beijing, People's Republic of China
A. Adelmann, A. Gsell, M. Seidel
PSI, Villigen PSI, Switzerland

The field emission model and the secondary emission model, as well as 3D boundary geometry handling capabilities, are needed to efficiently and precisely simulate multipacting phenomena. These models have been implemented in OPAL, a parallel framework for charged particle optics in accelerator structures and beam lines. The models and their implementation are carefully benchmarked against a non-stationary multipacting theory. A dedicated multipacting experiment with nanosecond time resolution for the classic parallel plate geometry has also successfully shown the validity of OPAL model. Multipacting phenomena, in the CYCIAE-100 cyclotron, under construction at China Institute of Atomic Energy, are expected to be more severe during the RF conditioning process than in separate-sector cyclotrons. This is because the magnetic fields in the valley are stronger, which may make the impact electrons easier to reach energies that lead to larger multipacting probabilities. We report on simulation results for CYCIAE-100, which gives us an insight view of the multipacting process and help to develop cures to suppress these phenomena.

Slides TU2PB01 [7.012 MB]

TU2PB03

Heat Transfer Study and Cooling of 10 MeV Cyclotron Cavity

cavity, cyclotron, factory, ion

150

S. Saboonchi, H. Afarideh
AUT, Tehran, Iran
M.R. Asadi
PPRC, Tehran, Iran
J.-S. Chai, M. Ghergherehchi
SKKU, Suwon, Republic of Korea

The most important problem in mechanical design of RF cavity of cyclotron is generated heat by RF power loss. An optimized cooling system for cavity is necessary to prevent Dee damaging and minimizing error function of cyclotron created by displacements. Also optimization of water circuit and water flow is essential because it affects unwanted vibrations and manufacturing. In this paper an attempt has been done to design an optimized cooling system for the cavity of a 10 MeV cyclotron with frequency of 69 MHz and 50 KW RF power using ANSYS and CST software.

TU2PB04

Resonator System for the BEST 70 MeV Cyclotron

controls, cyclotron, LLRF, cavity

153

V. Sabaiduc, G. Gold, B.A. Versteeg
BCSI, Vancouver, Canada
J. Panama
Best Theratronics Ltd., Ottawa, Ontario, Canada

Best Cyclotron Systems Inc. is presently developing a 70 MeV cyclotron for radioisotope production and research purpose. The RF system comprises two separated resonators driven by independent amplifiers to allow for the phase and amplitude modulation technique to be applied for beam intensity modulation. The resonators are presently in the commissioning phase consisting of cold test measurements followed by high power commissioning in the cyclotron. Preliminary simulation results have been reported and are: 56MHz operation (fourth harmonic, half-wave resonator design), 60 to 70kV dee voltage, quality factor 8000 with the estimated dissipated power of 17kW per resonator. The electromagnetic modeling has been done with CST Microwave Studio. All simulation results showed a very conservative design with typical parameters for the energy and size of the resonators. The paper will present the measurement results on a cold test set-up configuration as well as the commissioning with high power in the cyclotron.

Slides TU2PB04 [4.920 MB]

TUPPT023

Design and Simulation of Cavity for 10 MeV Compact Cyclotron

cavity, cyclotron, coupling, acceleration

200

V. Afzalan, H. Afarideh, R. Azizi
AUT, Tehran, Iran
J.-S. Chai, M. Ghergherehchi
SKKU, Suwon, Republic of Korea

RF system is known as one of the most vital parts to produce the efficient accelerator system. In this paper, the RF system and cavity of 10 MeV AVF ( Azimuthally Varying Field ) Cyclotron for radioisotope production are designed. The Cyclotron works on 4th harmonic with Dee's voltage of 50 KV. In order to supply the expected accelerating voltages RF power coupling and RF tuner has been considered. The RF system is simulated using commercially available simulator, CST Microwave Studio code. In contrast the geometry of cavity is optimized to achieve suitable Q value in desired frequency. Since the factors are non-ideal during the fabrication process, the actual Q value of cavities is estimated.

TUPPT025

Resonator System for the BCSI Test Stand Cyclotron

cyclotron, cavity, controls, LLRF

206

G. Gold, V. Sabaiduc, J. Zhu
BCSI, Vancouver, Canada
J. Panama
Best Theratronics Ltd., Ottawa, Ontario, Canada
L. AC. Piazza
INFN/LNL, Legnaro (PD), Italy

Best Cyclotron Systems Inc. is presently developing a test facility for beam injection into a center region cyclotron operating at maximum 1MeV. The test stand cyclotron will operate at various fixed frequencies that will cover the entire range from 49MHz to 80MHz as estimated for the current cyclotron models under development at BCSI. The resonator was designed with a variable coaxial section allowing for the frequency to be continuously adjusted as required for the particular model in study. Having interchangeable dee tip geometries presented various thermal management challenges which have been addressed. Three operational frequencies, 49MHz, 56MHz and 73MHz have been simulated with CST Microwave Studio. The paper will report the theoretical parameters of the cavity, mechanical design considerations and resonator commissioning on the first operational frequency of 49MHz.

TUPPT029

Design Study of a 83.2 MHz RF Cavity for the 9 MeV Compact Cyclotron

cavity, cyclotron, ion, impedance

215

S. Shin, J.-S. Chai, J.C. Lee
SKKU, Suwon, Republic of Korea
B.N. Lee
KAERI, Daejon, Republic of Korea

Funding: National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (2010-0025953)
A compact cyclotron accelerating H⁻ ion for producing a radioactive isotope FDG (FluoroDeoxyGlucose) for PET (Positron Emission Tomography) has been designed at Sungkyunkwan University. The H⁻ ion which generated from the PIG (Panning Ion Gauge) ion source will be accelerated at the normal conducting RF cavity which uses 83.2 MHz of resonance frequency and extracted at the carbon foil striper at the energy of 9 MeV. This cyclotron has to be small to install local hospital while FDG production needs more than 9 MeV of proton beam energy. Chasing two hare at once, deep valley type of magnet has been selected for high energy and compact cyclotron. Due to the small size of valley space where RF cavities will be installed, lots of difficulties have been introduced. Despite of those difficulties at the designing process, we could achieve resonance frequency of 83.2 MHz and Q-factor of 4500 with very compact size of RF cavity.

TUPSH002

Design and Construction of Combination Magnet for CYCIAE-100

proton, cyclotron, extraction, status

221

S.M. Wei, Shizhong. An, M. Li, C. Wang, M. Yin, T.J. Zhang, X. Zheng
CIAE, Beijing, People's Republic of China

The high intensity compact cyclotron CYCIAE-100 being constructed at China Institue of Atomic Energy (CIAE) is designed to extract proton beam from 75MeV to 100MeV in two opposite directions by stripping foil. Two combination magnets have been designed to bend the proton beams with different energies into one common beam line. The combination magnets have been designed into the return yoke of the main magnet of CYCIAE-100 for the dynamic reason. 2 D and 3D simulation of these combination magnets has been finished, the machining of them has also been finished. The magnetic field of the combination magnets has been measured and the results show that the measurements are very closed to the calculation, indicating these two magnets can be used in the BRIF project.

TUPSH007

Improvement in Design of 10 MeV AVF Cyclotron Magnet

betatron, cyclotron, factory, magnet-design

233

R. Solhju, H. Afarideh, B. Mahdian
AUT, Tehran, Iran
J.-S. Chai, M. Ghergherehchi
SKKU, Suwon, Republic of Korea

Design study of a 10 MeV baby cyclotron which accelerates H− ions is started in March, 2012 at Amirkabir University of Technology (AUT). Up to this point, conceptual design of the cyclotron magnet is finished. This process has been done in two steps: initial design and then optimization. After finishing the initial design of the magnet by CST software and adopting hard-edge approximation for finding the pole tip, an optimization process has been followed to smooth the pole edge in order to decrease the tension in sharp edges of the pole. In this paper, we are going to explain about the optimization process in details. Actually, we tried to fit the best curve at the pole edges of the magnet with goal of having minimum magnetic field error. Also a short report of results which was obtained before optimization is provided here. Precision of this design is ensured by checking the magnetic field and beam dynamic parameters during the optimization.

TUPSH008

Conceptual Design of the 100 MeV Separated Sector Cyclotron

cyclotron, resonance, extraction, magnet-design

236

B. Mahdian, H. Afarideh, R. Solhju
AUT, Tehran, Iran
J.-S. Chai, M. Ghergherehchi
SKKU, Suwon, Republic of Korea

The 100 MeV separated sector cyclotron was designed at Amirkabir University of Technology (AUT), which was aimed for various applications including radioactive ion-beam (RIB) production and proton therapy. It has four separated sector magnets. The cyclotron magnet design was based on an iterative process starting from a simple model that requires the vision of the complete cyclotron and the possibility of integration of all subsystems. By computer simulation with the 3D (CST) and 2D (POSSION) codes, principle parameters of the cyclotron magnet system were estimated (pole radius 180 cm, outer diameter 640 cm, height 300 cm). The results showed that the isochronous deviations between simulated values and the calculation one are smaller than 5 Gauss at most radii and therefore fulfilled the requirements. This work has been done with high accuracy which is proved by particle trajectories and considered mesh range. It has been concluded that it can be possible to design and develop this high energy cyclotron by introducing simple model without using trim and harmonic coils.

TUPSH013

Design Study of 10 MeV H⁻ Cyclotron Magnet

cyclotron, magnet-design, radio-frequency, extraction

248

H.S. Kim, J.-S. Chai, M. Ghergherehchi, H.W. Kim, S.H. Kim, S.H. Lee
SKKU, Suwon, Republic of Korea

Funding: This work has been supported by National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning (NRF-2010-0025952).
For the past decades, PET (positron emission tomography) has been remarkable growth in market. PET using 18F is widely provided for cancer screening and expected to be installed at small and medium hospital for convenience of patients. At Sungkyunkwan University, 10 MeV H⁻ cyclotron, which produces 18F is being developed. In this paper, we demonstrated main magnet design and whole design procedure was explained. The result of design is verified by orbit analysis and single particle tracking. The description of the obtained result is presented in this paper.

TU3PB01

Bunch-Shape Measurements at PSI’s High-power Cyclotrons and Proton Beam Lines

proton, cyclotron, electron, cathode

257

R. Dölling
PSI, Villigen PSI, Switzerland

Longitudinal-transversal 2D-density distributions of the bunched 2.2 mA CW proton beam can now be measured at the 13 last turns of the Injector 2 cyclotron, at several locations in the connecting beam line to the Ring cyclotron, at the first two turns of the Ring cyclotron (all at energies around 72 MeV), as well as behind the Ring cyclotron (at 590 MeV). In the large part, distributions can be taken from several angles of view, separated each by 45°. The measurement systems at our facility have evolved with time; this paper gives the present status, performance, limits and typical results. Due to the limited space, we refer in the large part to our previous publications [1, 2, 3] and concentrate on recent findings and measurements and ideas for next steps.

Slides TU3PB01 [9.393 MB]

TU3PB04

TRIUMF Extraction Foil Developments and Contamination Reduction

electron, extraction, scattering, TRIUMF

269

Y.-N. Rao, R.A. Baartman, I.V. Bylinskii, V.A. Verzilov
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
J.M. Schippers
PSI, Villigen PSI, Switzerland

Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada.
We made important developments on the extraction probes and stripping foils at TRIUMF. One of the issues we had was the ⁷Be contamination being observed near the 1A stripper, and relatedly, stripping foils warped or even broke during use. This was deemed due to over-heating in the foil and the frame. Another issue was related to the beam spills. Beam spills are primarily caused by the large angle scattering from the stripping foil. It was thus suggested that thinner foils be used to minimize the scattering. In view of these 2 issues, improvements were made such that (1) highly-orientated pyrolytic graphite foils, of thickness around 2 mg/cm², are now used; (2) Tantalum frame is now used in place of the previous stainless steel. These changes, plus additional heat relief features introduced, have resulted in 4 times longer lifetime with the foil, and 5 to 10 times reduction to the tank contamination level around the extraction probe. Also, these improvements have led to significantly reduced amount of beam spill monitor trips. This paper presents these developments and outcomes, including the simulations and calculations performed.

Slides TU3PB04 [4.798 MB]

WE1PB02

The Rutgers Cyclotron: Placing Student's Careers on Target

cyclotron, focusing, ion, proton

291

K.J. Ruisard
Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
G.A. Hine, T.W. Koeth
UMD, College Park, Maryland, USA
A.J. Rosenberg
Stanford University, Stanford, California, USA

The Rutgers 12” Cyclotron is an educational tool used to introduce students to the multifaceted field of accelerator physics. Since its inception, the cyclotron has been under continuous development and is currently incorporated into the modern physics lab course at Rutgers University, as a semester-long mentored project. Students who participate in the cyclotron project receive an introduction to topics such as beam physics, high voltage power, RF systems, vacuum systems and magnet operation. Student projects have led to three different focusing pole geometries, including, most recently, a spiral edged azimuthally varying field (AVF) configuration. The Rutgers Cyclotron is often a student’s first encounter with an accelerator, and has inspired careers in accelerator physics.

Slides WE1PB02 [14.090 MB]

WE1PB04

A Novel Optical Method for Measuring Beam Phase and Width in the Rutgers 12-Inch Cyclotron

cyclotron, ion, focusing, proton

299

J.L. Gonski, S. Burcher, T.W. Koeth, J.E. Krutzler, S. Lazarov
Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
J. Beaudoin
UMD, College Park, Maryland, USA

We present an experimental longitudinal measurement of beam and phase slippage as a function of magnetic field deviation in a weak focusing field, using proton acceleration data from the Rutgers 12-inch cyclotron. A gated camera was used to determine beam arrival time from the radiation emitted by a fast ZnO:Ga doped phosphor target when struck by accelerated protons. Images integrated light emitted in 9 degree increments over a full 360-degree RF cycle. Analysis of relative image brightness allowed for the successful acquisition of relative phase shift and azimuthal beam width over several magnetic field strengths. Theoretical predictions and simulation via Poisson Superfish and SIMION software show good agreement with data, validating the optical method for qualitative measurements. This new method is independent of dee voltage and allows for measurements to be taken in the central region of the cyclotron, where other electrically based methods of measurement are challenging due to high RF electric fields. Such characteristics validate the use of gated camera imaging for cyclotron research, and motivate future refinement of this technique for a variety of studies.

Slides WE1PB04 [3.662 MB]

WE2PB02

Vlasov Equation Approach to Space Charge Effects in Isochronous Machines

space-charge, cyclotron, betatron, plasma

310

A.J. Cerfon, O. Bühler, J.V. Guadagni
Courant Institute of Mathematical Sciences, New York University, New York, USA
J.P. Freidberg, F.I. Parra Diaz
MIT/PSFC, Cambridge, Massachusetts, USA

Starting from the collisionless Vlasov equation, we derive two simple coupled two-dimensional fluid equations describing the radial-longitudinal beam vortex motion associated with space charge effects in isochronous cyclotrons. These equations show that the vortex motion can be intuitively understood as the nonlinear advection of the beam by the ExB velocity field, where E is the electric field due to the space charge and B is the applied magnetic field. This explains why elongated beams develop spiral halos while round beams are always stable. Solving the coupled equations numerically, we find good agreement between our model and 3-D Particle-In-Cell OPAL simulations*.
* J.J. Yang, A.Adelmann, M. Humbel, M. Seidel, and T.J. Zhang, Physical Review Special Topics Accelerators and Beams 13, 062401 (2010)

Slides WE2PB02 [1.166 MB]

WE2PB03

Transverse-Longitudinal Coupling by Space Charge in Cyclotrons

emittance, space-charge, cyclotron, focusing

315

C. Baumgarten
PSI, Villigen PSI, Switzerland

Based on a linear space charge model and on the results of PIC-simulations with OPAL, we analyze the conditions under which space charge forces support bunch compactness in high intensity cyclotrons and/or FFAGs. For this purpose we compare the simulated emittance increase and halo formation for different matched and mismatched particle distributions injected into a separate sector cyclotron with different phase curves.

Slides WE2PB03 [3.187 MB]

WEPPT009

Transverse Phase-Space Distributions of Low Energy Ion Beams Extracted from an ECR Ion Source

ion, ion-source, emittance, extraction

341

S. Saminathan
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
J.P.M. Beijers, S. Brandenburg, H.R. Kremers, V. Mironov
KVI, Groningen, The Netherlands

Transverse phase-space distributions of low-energy ion beams extracted from ECR ion sources often show higher-order effects caused by ion-optical aberrations. Understanding these effects is mandatory to keep emittance growth and the resulting beam losses in low-energy beam transport lines under control. We present the results of an experimental and theoretical study of beam extraction and transport in the AGOR injection line at KVI. Particle tracking simulations have been performed of a multi-component neon ion beam extracted from an ECR ion source to calculate 4D phase-space distributions at various positions along the beamline. The simulations compare well with beam profile and emittance measurements.

WEPPT012

Beam Dynamics in Presence of Imperfection Fields Near the Extraction Zone of Kolkata Superconducting Cyclotron

extraction, cyclotron, resonance, betatron

347

J. Debnath, U. Bhunia, A. Chakrabarti, M.K. Dey, A. Dutta, Z.A. Naser, S. Paul, J. Pradhan, V. Singh
VECC, Kolkata, India

Funding: VECC, DAE
The superconducting cyclotron at Kolkata has accelerated the ion beams up to the extraction radius producing neutrons via nuclear reactions. After that the beam extraction process has been tried exhaustively. But rigorous beam extraction trials indicate towards some kind of error field, which was not possible to balance with the trim coil operated in harmonic-coil mode. It is found that the beam is being off-centered by a large amount after crossing the resonance zone and it is not reaching the extraction radius in proper path. This paper will be emphasizing the effect of various kind of error field on the beam. However, the magnetic field is being measured again to know the exact distribution of the field.

WEPPT014

Analysis of Phase Bunching in the Central Region of the JAEA AVF Cyclotron

acceleration, bunching, cyclotron, ion

350

N. Miyawaki, H. Kashiwagi, S. Kurashima, S. Okumura
JAEA/TARRI, Gunma-ken, Japan
M. Fukuda
RCNP, Osaka, Japan

Phase bunching generated in the central region of an AVF cyclotron was estimated by a simplified geometric trajectory analysis model for particles traveling from the first to the second acceleration gap. In principle, a rising slope of a dee-voltage at the first acceleration gap is more or less effective for production of the phase bunching. The phase difference between particles at the second acceleration gap depends on combination of four parameters: the acceleration harmonic number (h), a span angle of the dee electrode, a span angle from the first to the second acceleration gap, a ratio between a peak dee-voltage and an extraction voltage of an ion source. In the case of the JAEA AVF cyclotron, the effective phase bunching was realized for h = 2 and 3, and the geometric condition of phase bunching was unrealistic for h = 1. An orbit simulation for the JAEA AVF cyclotron indicated that the initial beam phase width of 40 RF degrees for h = 2 was compressed to 11 RF degrees. The phase bunching evaluation based on the simplified geometric trajectory analysis was consistent with the orbit simulation result, and practical phase bunching was verified by beam phase width measurement.

WEPPT018

Behavior of Space Charge Dominated Beam Envelope in Central Region of High Current Cyclotron

space-charge, acceleration, injection, cyclotron

359

R. Azizi, H. Afarideh, V. Afzalan
AUT, Tehran, Iran
J.-S. Chai, M. Ghergherehchi
SKKU, Suwon, Republic of Korea

In this paper the space charge effect in the two first turn after injection has been investigated. In order to determine beam envelopes, two corresponding equations were chosen. In addition, all steps of calculation were done by MATLAB program. It should be mentioned limiting current and also magnetic, electrical field and edge effect has been considered. As far as, the high current cyclotron with 0.8π mm mrad emittance has been studied and current alters till 10 mA.*
*M. Reiser, Theory and Design of Charged Particle Beams (Wiley, New York, 1994), Chapters.3 and 4.

WEPPT019

Investigation on the Transverse Emittance Growth of Intense Beam during Bunching

bunching, emittance, space-charge, solenoid

361

P. Sing Babu, A. Goswami, V.S. Pandit
VECC, Kolkata, India

Bunchers are widely used in the injection system of cyclotrons to transform dc beam into a bunched beam in a desired phase width. In the case of low beam current, the longitudinal compression of beam has very little effect on the transverse dynamics. However in the case of high current bunching the increase of current in the specified bunch width as the beam advances affects the transverse behavior. A 2D particle-in-cell code has been developed to study the transverse dynamics during beam bunching in the injection system of 10MeV, 5mA compact proton cyclotron. We have used a linear increase of beam current in the specified bunch width from the buncher position to the time focus. In the PIC method this effect is introduced by reweighting the charge and mass of the macroparticles during the transport with longitudinal compression. The evolutions of beam envelope and emittance growth have been estimated for various initial particle distributions. It is observed that the rms beam size is independent of particular beam distribution whereas rms emittance grows with nonuniformity of the distribution and peaks near the time focus.

WEPPT027

Design of the Injection into the 800 MeV/amu High Power Cyclotron

injection, cyclotron, closed-orbit, septum

375

M. Haj Tahar, F. Méot
BNL, Upton, Long Island, New York, USA
L. Calabretta
INFN/LNS, Catania, Italy
A. Calanna
CSFNSM, Catania, Italy

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We present the design of the injection line into a separated sector cyclotron (SSC) aimed at the production of a high power beam of 800MeV/amu molecular H²⁺ for ADS-Reactor applications. To work out the beam line parameters and beam dynamics simulations, including the first accelerated turns, we used the ray-tracing code Zgoubi and the OPERA magnetic field map of the cyclotron sector*. We simulated the injection path of the H²⁺ and evaluated both radial and vertical injection schemes in order to evaluate the parameters so derived. The paper details and discusses various aspects of that design study and its outcomes.
* A.Calanna et al., A multi-megawatt ring cyclotron to search for CP violation in the neutrino sector, April 2011, e-Print: arXiv:1104.4985

WEPPT029

The Cyclotron Complex for the DAEδALUS Experiment

cyclotron, injection, acceleration, extraction

381

A. Calanna, D. Campo, J.M. Conrad
MIT, Cambridge, Massachusetts, USA
L. Calabretta
INFN/LNS, Catania, Italy
M. Haj Tahar, F. Méot
BNL, Upton, Long Island, New York, USA

The cyclotron complex for the DAEδALUS CP-Violation neutrino experiment consists of a compact cyclotron able to accelerate high-current (5 electrical milliamp) H²⁺ beams up to an energy of 60 MeV/amu, cleanly extract this beam with a conventional septum arrangement, and transport it to a superconducting ring cyclotron able to accelerate the beam up to 800 MeV/amu. H²⁺ is dissociated with thin stripping foils for efficient extraction as protons for transport to a megawatt-class target for neutrino production. The injection cyclotron will be similar to the one proposed for the IsoDAR experiment (Paper WEPPT029). The Ring cyclotron is similar in size and engineering concept to the SRC at RIKEN. Space-charge dominated beam dynamics simulations using OPAL have been performed for an 8-sector geometry, and indicate acceptable transmission and low beam losses. Subsequent engineering magnet-design studies of Minervini et al. point to a 6-sector configuration as more practical. Recalculation of the beam dynamics for this new configuration will be performed in the coming year. Results of the studies conducted to date will be presented.

WE3PB01

Experimental Study of Resonance Crossing with a Paul Trap

resonance, emittance, ion, plasma

409

H. Sugimoto
KEK, Ibaraki, Japan

The effect of resonance crossing on beam stability is studied systematically by employing a novel tabletop experimental tool and a multiparticle simulation code. A large number of ions are confined in a compact linear Paul trap to reproduce the collective beam behavior. We can prove that the ion plasma in the trap is physically equivalent to a charged-particle beam propagating through a strong focusing channel. The plasma confinement force is quickly ramped such that the trap operating point traverses linear and nonlinear resonance stop bands as in cyclotrons and FFAGs.

Slides WE3PB01 [9.757 MB]

WE4PB01

Tracking in a Cyclotron with Geant4

TRIUMF, cyclotron, proton, acceleration

423

F.W. Jones, T. Planche, Y.-N. Rao
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Building on its precursor GEANT, the tracking and simulation toolkit Geant4 has been conceived and realised in a very general fashion, with much attention given to the modeling of electric and magnetic fields and the accuracy of tracking charged particles through them. As evidenced by the G4Beamline application, Geant4 offers a unique simulation approach to beam lines and accelerators, in a 3D geometry and without some of the limitations posed by conventional optics and tracking codes. Here we apply G4Beamline to the TRIUMF cyclotron, describing the generation and input of the field data, accuracy of closed orbits, stability of multi-turn tracking, tracking accelerated orbits, and phase acceptance. Geant4's 3D visualization tools allow detailed examination of trajectories as well as a particle's-eye view of the acceleration process.

Slides WE4PB01 [4.146 MB]

WE4PB02

An All-Purpose Accelerator Code, Zgoubi

radiation, damping, polarization, synchrotron

426

F. Méot
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The ray-tracing code Zgoubi* has long been 6D-tracking through all possible types of fixed field rings**, including, recently, 6D transmission from injection-up to extraction-down in high power cyclotrons in the frame of ADS-Reactor R/D. This is to be added to the long exploited many other capabilities of the code as spin transport, in-flight decay, synchrotron radiation energy loss, etc. An overview will be given, including recent space-charge developments, with illustration including recent high power cyclotron applications.
*http://sourceforge.net/projects/zgoubi/, http://www.osti.gov/bridge/basicsearch.jsp
**6-D beam dynamics simulations in FFAGs, F. Meot, ICFA Beam Dyn. Newslett.43:44-50 (2007)

Slides WE4PB02 [4.414 MB]

TH2PB04

A Multi-Leaf Faraday Cup Especially for Proton Therapy of Ocular Tumors

proton, radiation, cyclotron, ion

458

C.S.G. Kunert, J. Bundesmann, T. Damerow, A. Denker
HZB, Berlin, Germany
A. Weber
Charite, Berlin, Germany

The Helmholtz-Zentrum Berlin (HZB) provides together with the University Hospital Charité in Berlin a treatment of eye tumors with a proton beam. The 68 MeV proton beam is delivered by an isochronous cyclotron as main accelerator. In tumor irradiation treatment the positioning of the radiation field is very important. In eye tumor treatment it is even more important, due to the small and sensitive structures in the eye. Hence, due to the well defined Bragg peak, a proton beam is a good choice to achieve rather small fields of dose delivery. Again, due to the small structures in the eye, one needs to know the proton beam energy and the proton beam range with a high accuracy. One possible solution for a quick and high precision measurement of the range of such proton beams is a Multi-Leaf Faraday Cup (MLFC). This work has the task to develop such a MLFC concerning the special requirements of the eye tumor therapy. In this presentation an overview of the progress of this work will be given, regarding the MLFC principles and issues such as the first technical realization.

Slides TH2PB04 [5.358 MB]