IPAC2018 - List of Keywords (extraction)

Paper	Title	Other Keywords	Page
MOPMF002	Pre-Booster Ring Considerations for the FCC e⁺e⁻ Injector	booster, emittance, damping, wiggler	83
	O. Etisken Ankara University, Faculty of Sciences, Ankara, Turkey F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland A.K. Çiftçi Izmir University of Economics, Balçova/Izmir, Turkey
	The FCC-e⁺e⁻ injector complex needs to produce and to transport a high-intensity e⁺/e⁻ beam at a fast repetition rate for topping up the collider at its collision energy. Two different options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and a completely new ring. The purpose of this paper is to explore the needs and parameters of the existing SPS and the conceptual design of an alternative accelerator ring with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the basic parameters of both choices are established, including the optics design and layout updates. Consideration for non-linear dynamics optimization and the impact of intra beam scattering are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF002
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MOPMF054	Comparison of Different Transverse Emittance Measurement Techniques in the Proton Synchrotron Booster	emittance, proton, optics, booster	232
	G.P. Di Giovanni, S.C.P. Albright, V. Forte, M.A. Fraser, G. Guidoboni, B. Mikulec, F. Roncarolo, A. Santamaría García CERN, Geneva, Switzerland
	The measurement of the transverse emittance in an accelerator is a crucial parameter to evaluate the performance of the machine and to understand beam dynamics processes. In recent years, controlling and understanding the emittance became particularly relevant in the Proton Synchrotron Booster (PSB) at CERN as part of the LHC Injectors Upgrade (LIU). The LIU project is a necessary step to achieve the goals of the High-Luminosity LHC project. In this framework, an accurate and reliable emittance measurement of high brightness beams is mandatory to study the brightness reach of the LHC injectors. In the PSB there are two main instruments available for emittance measurements: wire scanners and secondary-emission (SEM) grids. In this paper emittance measurements performed during the 2017 physics run with these two systems are compared, taking into account various systematic error sources.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF054
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MOPMF063	Asynchronous Beam Dump Tests at LHC	proton, beam-losses, quadrupole, operation	265
	C. Wiesner, W. Bartmann, C. Bracco, E. Carlier, L. Ducimetière, M.I. Frankl, M.A. Fraser, B. Goddard, C. Heßler, T. Kramer, A. Lechner, N. Magnin, V. Senaj, D. Wollmann CERN, Geneva, Switzerland
	The detailed understanding of the beam-loss pattern in case of an asynchronous beam dump is essential for the safe operation of the future High Luminosity LHC (HL-LHC) with nearly twice the nominal LHC beam intensity, leading to correspondingly higher energy deposition on the protection elements. An asynchronous beam dump is provoked when the rise time of the extraction kickers is not synchronized to the 3 us long particle-free abort gap. Thus, particles that are not absorbed by dedicated protection elements can be lost on the machine aperture. Since asynchronous beam dumps are among the most critical failure cases of the LHC, experimental tests at low intensity are performed routinely. This paper reviews recent asynchronous beam dump tests performed in the LHC. It describes the test conditions, discusses the beam-loss behaviour and presents simulation and measurement results. In particular, it examines a test event from May 2016, which led to the quench of four superconducting magnets in the extraction region and which was studied by a dedicated beam experiment in December 2017.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF063
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MOPMF070	High Voltage Design for the Electrostatic Septum for the Mu2e Beam Resonant Extraction	cathode, high-voltage, vacuum, simulation	289
	M.L. Alvarez, C.C. Jensen, D.K. Morris, V.P. Nagaslaev, H. Pham, D.G. Tinsley Fermilab, Batavia, Illinois, USA
	Two electrostatic septa (ESS) are being designed for the slow extraction of 8GeV proton beam for the Mu2e experiment at Fermilab. Special attention is given to the high voltage components that affect the performance of the septa. The components under consideration are the high voltage (HV) feedthrough, cathode standoff (CS), and clearing electrode ceramic standoffs (CECS). Previous experience with similar HV systems at Fermilab was used to define the evaluation criteria of the design of the high voltage components. Using electric field simulation software, high E-field intensities on the components and integrated field strength along the surface of the dielectric material were minimized. Here we discuss the limitations found and improvements made based on those studies.
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MOPML021	Shorter Treatment Time by Intensity Modulation with a Betatron Core Extraction	betatron, proton, radiation, synchrotron	439
	M. G. Pullia, E. Bressi, G.M.A. Calvi, M. Donetti, L. Falbo, S. Foglio, V. Lante, A. Parravicini, C. Priano, E. Rojatti, S. Savazzi, C. Viviani CNAO Foundation, Pavia, Italy
	The CNAO (National Center for Oncological Hadrontherapy) main accelerator is a synchrotron capable to accelerate carbon ions up to 400 MeV/u and protons up to 250 MeV. Three treatment rooms are available and are equipped with horizontal beam lines; one of the treatment rooms also features a vertical treatment line to allow additional treatment ports. All of the beamlines are equipped with an active beam scanning system for dose delivery. With such a dose distribution technique, particles are sent to different depths by changing the energy from the synchrotron and are moved transversally by means of two scanning magnets. The number of particles to be deposited in each position varies strongly within the same iso-energetic layer. Part of the dose needed in a given position is in fact delivered by particles directed to deeper layers. In order to maintain the required precision on the number of particles delivered to each spot, the intensity is reduced when spots that require low number of particles are present in a layer. A method to shorten the irradiation time based on variable intensity within the same layer is presented that works also with a betatron based extraction scheme.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML021
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MOPML025	Slow Extraction Optimization at the MedAustron Ion Therapy Center: Implementation of Front End Acceleration and RF Knock Out	proton, acceleration, synchrotron, kicker	453
	A. De Franco, L. Adler, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl EBG MedAustron, Wr. Neustadt, Austria L.C. Penescu Abstract Landscapes, Montpellier, France
	Funding: This project has received funding from the European Union's Horizon 2020 research and Innovation programme under the Marie Skłodowska-Curie grant agreement No 675265. MedAustron is a synchrotron-based ion therapy center allowing tumour treatment with protons and other light ion species, in particular C⁶⁺. Commissioning of all fixed lines, two horizontal and one vertical, has been completed for protons and in parallel to the commissioning of a gantry and C⁶⁺, a facility upgrade study is progressing. The upgrade study encompasses the optimization of the slow extraction mechanism by employing the RF empty bucket channeling and RF Knock Out techniques. The former is a front end acceleration technique that suppress spill ripples, fundamental to safely operate the machine at the highest intensities. The latter is an alternative extraction technique which opens up interesting possibilities for fast beam energy and intensity modulations. In this work, we quantify spill smoothening effect achieved with the first and report the results of a feasibility study of the second using a Schottky monitor as a transverse kicker.
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MOPML035	Betatron Frequencies in Cotangential Trajectory Accelerator for Proton Beam Therapy	betatron, alignment, cyclotron, resonance	485
	T. Aoki, F. Ebina, C. Hori, Y. Nakashima, T. Seki Hitachi Ltd., Ibaraki-ken, Japan T. Hae Hitachi Ltd., Hitachi Research Laboratory, Ibaraki-ken, Japan
	It is important that downsizing of an accelerator for spreading proton beam therapy. The synchrotron is the solution of accelerator of proton beam therapy system which can vary energy of extracted beam in the range of from 70 MeV to 235 MeV with a merit of requiring no energy selection system. In order to downsize accelerator with above merit, we suggested smaller variable energy accelerator which have cotangential trajectories. This new type accelerator is expected to realize variability of beam energy with static main magnetic field. One of technological problems of this new type accelerator is stability of betatron oscillation. We plan to utilize week focusing field as main magnetic field, which is decreasing on the radial direction outward and uniform in longitudinal direction, of this new type accelerator. We found the main magnetic field which realizes stable betaron oscillations in the range of from 70 MeV to 235 MeV as the result of estimating the betaron oscillations in this main field by numerical calculation. We report new type accelerator concept and results of analysis of betatron oscillation in cotangential trajectories.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML035
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TUXGBF3	Reduction of the Kicker Impedance Maintaining the Performance of Present Kicker Magnet at RCS in J-PARC	kicker, impedance, simulation, synchrotron	616
	Y. Shobuda, Y. Irie, T. Takayanagi, T. Togashi, K. Yamamoto, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The present kicker at RCS in J-PARC is designed to make a waveform by superposing the forward and backward currents from the power source to extract beams, so that one terminal of the kicker is shorted and the other one is open. On the other hand, the kicker impedance is the dominant source of the beam instability at the RCS. This report proposes a scheme to reduce the kicker impedance, maintaining the beneficial of the superposition of currents with the present kicker magnet.
	Slides TUXGBF3 [9.947 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBF3
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TUPAF004	Status of the MedAustron Beam Commissioning with Protons and Carbon Ions	MMI, proton, dipole, synchrotron	665
	C. Kurfürst, L. Adler, A. De Franco, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl EBG MedAustron, Wr. Neustadt, Austria L.C. Penescu Abstract Landscapes, Montpellier, France
	MedAustron is a synchrotron-based Particle Therapy Accelerator located in Wiener Neustadt, Austria, which is delivering beams for medical treatment since end of 2016. The accelerator provides clinical proton beams in the energy range 62-252 MeV and is designed to provide carbon ions in the range 120-400 MeV/n to three ion therapy irradiation rooms IRs, including a room with a proton Gantry. Proton beams of up to 800 MeV will be provided to a fourth room dedicated to research. Presently, proton beams are delivered to the fixed horizontal beam lines of three rooms. Beam commissioning of the vertical beam line of the second IR is being completed and the beam line is in preparation for clinical treatment. Commissioning of the accelerator with carbon ions is advancing and first clinical beams have been sent to the IRs, while the preparation for the Gantry beam line is ongoing. A slow extraction 3rd order resonance method is used to extract particles from the synchrotron between 0.1-10 seconds to favor control of the delivered dose during clinical treatments. The main characteristics of the accelerator and results obtained during the latest commissioning activities are presented.
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TUPAF010	Empty Sweeping Bucket for Slow Extraction	resonance, acceleration, hadrontherapy, synchrotron	676
	L. Falbo, E. Bressi, C. Priano CNAO Foundation, Milan, Italy
	The extraction process from a synchrotron is one of the most important aspects of an accelerator devoted to clinical purposes, like the hadrontherapy in which hadron beams are used to treat tumors. Indeed the quality of the dose delivered to the patient, in terms of dose uniformity and precision in the beam characteristics, is defined by the way in which the beam is extracted. The quality of the extracted beam (the so called spill) is strongly affected by the stability of the power supplies of the synchrotron magnets whose field stability creates a ripple in the intensity of the extracted beam itself. When it is not possible to improve the power supply stability, it is needed to apply some additional techniques in order to cure the spill ripple. At CNAO, the italian hadrontherapy facility, it has been thought to improve the Empty Bucket Channelling technique by using an energy-moving bucket instead of a stationary bucket. The paper shows the implementation, the advantages and the efficacy of this RF gymnastic, named 'Empty Sweeping Bucket'.
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TUPAF020	Performance of the CERN Low Energy Ion Ring (LEIR) with Xenon beams	injection, MMI, linac, controls	705
	R. Alemany-Fernández, S.C.P. Albright, O. Andujar, M.E. Angoletta, J. Axensalva, H. Bartosik, G. Baud, N. Biancacci, M. Bozzolan, S. Cettour Cave, K. Cornelis, J. Dalla-Costa, M. Delrieux, A. Dworak, A. Findlay, F. Follin, A. Frassier, M. Gabriel, A. Guerrero, M. Haase, S. Hirlaender, S. Jensen, V. Kain, L.V. Kolbeck, Y. Le Borgne, D. Manglunki, O. Marqversen, S. Massot, D. Moreno Garcia, D.J.P. Nicosia, S. Pasinelli, L. Pereira, D. Perez, A. Rey, J.P. Ridewood, F. Roncarolo, A. Saá Hernández, R. Scrivens, O.G. Sveen, G. Tranquille, E. Veyrunes CERN, Geneva, Switzerland
	In 2017 the CERN Low Energy Ion Ring demonstrated once more the feasibility of injecting, accumulating, cooling and accelerating a new nuclei, 129Xe39 . The operation of this new ion species started at the beginning of March with the start up of the xenon ion source and the Linac3. Ten weeks later the beam arrived to the Low Energy Ion Ring (LEIR) triggering the start of several weeks of beam commissioning in view of providing the injector complex with Xenon beams for different experiments and a series of machine development experiments in LEIR. Two types of beams were setup, the so called EARLY beam, with a single injection into LEIR from Linac3, and the NOMINAL beam with up to seven injections. 2017 was as well an interesting year for LEIR because several improvements in the control system of the accelerator and in the beam instrumentation were done in view of increasing the machine reliability. This paper summarises the beam commissioning phase and all the improvements carried out during 2017.
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TUPAF032	Beam Transfer Line Design to the SPS Beam Dump Facility	target, proton, experiment, quadrupole	751
	Y. Dutheil, J. Bauche, M. Calviani, L.A. Dougherty, M.A. Fraser, B. Goddard, C. Heßler, J. Kurdej, E. Lopez Sola CERN, Geneva, Switzerland
	Studies for the SPS Beam Dump Facility (BDF) are ongoing within the scope of the Physics Beyond Collider project. The BDF is a proposed fixed target facility to be installed in the SPS North Area, to accommodate the SHiP experiment (Search for Hidden Particles), which is most notably aiming at studying hidden sector particles. This experiment requires a high intensity slowly extracted 400 GeV proton beam with 4·10¹³ protons per 1 s spill to achieve 4·10¹⁹ protons on target per year. The extraction and transport scheme will make use of the first 600 m of the existing North Area extraction line. In this paper, we will present the design of the additional 600 m of transfer line towards BDF branching off from the existing line and discuss the detailed design of the BDF beam line, its components and optics. We present the latest results on the study and design of a new laminated Lambertson splitter magnet to provide fast switch between the current North Area experiments and the BDF. The latest specification of a dipole dilution system used to reduce the local peak power of the beam on the target is also presented.
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TUPAF033	Beam Optics Studies for BDF and for Tests of a Prototype Target	target, optics, emittance, proton	754
	C. Heßler, M. Calviani, Y. Dutheil, M.A. Fraser, B. Goddard, V. Kain, E. Lopez Sola, F.M. Velotti CERN, Geneva, Switzerland
	Within the frame of the Physics Beyond Collider project a new fixed target facility at the SPS North Area, the so-called Beam Dump Facility (BDF), is under study. BDF requires a high intensity slowly extracted 400 GeV proton beam with 4·10¹³ protons per 1 s spill to achieve 4·10¹⁹ protons on target per year. This results in an exceptionally high average beam power of 355 kW on the target, which is a major challenge. To validate the target design, a test of a prototype target is planned for 2018 at an existing North Area beam line. A large part of this beam line is in common with the future BDF beam line with comparable beam characteristics and several measurement campaigns were performed in 2017 to study the optics of the line in preparation for the test. The intrinsic characteristics of the slow extraction process make the precise characterisation of the beam reaching the target particularly challenging. This paper presents beam and lattice characterisation methods and associated measurement results.
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TUPAF035	Observations of SPS Slow-Extracted Spill Quality Degradation and Possible Improvements	quadrupole, power-supply, simulation, experiment	761
	F.M. Velotti, H. Bartosik, K. Cornelis, M.A. Fraser, B. Goddard, S. Hirlaender, V. Kain, O. Michels, M. Pari CERN, Geneva, Switzerland
	The SPS delivers slow extracted proton and heavy ion spills of several seconds to the North Area fixed target experiments with a very high duty factor. Reduced machine reproducibility due to magnetic history and power supply ripples on the main circuits lead however to frequent degradation of the spill duty factor. In this paper, the measured effect of the SPS magnetic history on spill quality and principal machine parameters is presented. Another detailed measurement campaign was aimed at characterising the frequency content and response of the spill to noise on the main power supplies ripples. The main findings of this study will also be reported. Finally, simulations of possible improvements based on the data acquired are discussed, as well as an extrapolation to the possible spill quality after the implementation of the improvements.
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TUPAF050	Beam Dynamics Simulations of the Effect of Power Converter Ripple on Slow Extraction at the CERN SPS	quadrupole, emittance, sextupole, experiment	818
	J. Prieto, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland
	The SPS provides slowly extracted protons at 400 GeV/c to CERN's North Area Fixed Target experiments over spills of duration from 1-10 seconds. Low frequency ripple on the current in the main magnets originating from their power converters is a common issue that degrades the slow-extracted spill quality. In order to better understand how the stability of the power converters affects losses, beam emittance and spill quality, particle tracking simulations were carried out using MAD-X and compared to measurements, with the impact of each magnet circuit investigated systematically. The implications for the performance of the SPS slow extraction are discussed.
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TUPAF051	Investigating Beam Loss Reduction with Octupoles During Slow Extraction in the CERN SPS	octupole, multipole, optics, simulation	822
	L.S. Stoel, M. Benedikt, M.A. Fraser, B. Goddard CERN, Geneva, Switzerland K.A. Brown BNL, Upton, Long Island, New York, USA
	Several different methods for reducing beam loss during resonant slow extraction at the CERN Super Proton Synchrotron (SPS) are being studied. One of these methods is the use of multipoles to manipulate the separatrices in order to reduce the fraction of protons hitting the thin wires of the electrostatic extraction septum (ES). In this paper the potential of using octupoles for this purpose is explored. Beam dynamics simulations using both a simplified model and full 6D tracking in MAD-X are presented. The performance reach of such a concept at the SPS is evaluated and the potential of future machine development studies using the octupoles already installed is discussed.
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TUPAF052	Effects of Electrostatic Septum Alignment on Particle Loss During Slow Extraction at CERN SPS	alignment, simulation, operation, septum	826
	J. Prieto, Y. Dutheil, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland M.A. Kagan SLAC, Menlo Park, California, USA
	Slow extraction is an intrinsically lossy process that splits the beam with an electrostatic septum (ES), employing a thin-wire array to delimit the high electric field region that deflects the beam into the extraction channel. At CERN's Super Proton Synchrotron (SPS) the ES is over 16 m long and composed of 5 separate units containing separate wire-arrays that can be moved independently. The tanks are all mounted on a single support structure that can move the ensemble coherently. As a result, the large number of positional degrees of freedom complicates the alignment procedure in operation. Obtaining and maintaining accurate alignment of the ES with the beam is therefore crucial for minimising beam loss. In this paper, we investigate the alignment procedure for different operational scenarios using particle tracking simulations to understand the beam loss along the extraction straight as a function of the relative positions of each of the 5 separate ES units. An important aspect of the study was to understand the required alignment tolerance to achieve optimum extraction efficiency for a given configuration of wire-array thicknesses.
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TUPAF053	Optimization of Diffuser (Pre-Scatterer) Configurations for Slow Extraction Loss Reduction at Electrostatic Septa	septum, scattering, simulation, proton	830
	B. Goddard, B. Balhan, J.C.C.M. Borburgh, M.A. Fraser, L.O. Jorat, V. Kain, C. Lolliot, L.S. Stoel, P. Van Trappen, F.M. Velotti CERN, Geneva, Switzerland D. Barna Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary V.P. Nagaslaev Fermilab, Batavia, Illinois, USA
	Uncontrolled beam loss at the electrostatic septum is a performance limit for several existing or planned high power hadron accelerators delivering slow-extracted spills to fixed targets. A passive diffuser, or pre-scatterer, in a suitable configuration has been shown to reduce such beamloss significantly, with the actual gain factor depending on the parameters and details of the extraction process and hardware. In this paper, the optimization of diffuser configurations is investigated for a range of beam energies and extraction conditions, and the sensitivity to the available parameters explored via simulation results. The advantages and limitations of the diffuser are discussed and conclusions drawn concerning the specific case studies of the 8 GeV Fermilab debuncher ring and 400 GeV CERN SPS.
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TUPAF054	Slow Extraction Efficiency Measurements at the CERN SPS	proton, operation, septum, simulation	834
	M.A. Fraser, K. Cornelis, L.S. Esposito, B. Goddard, V. Kain, F. Roncarolo, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland
	The high efficiency of most slow extraction systems makes quantifying the exact amount of beam lost in the process extremely challenging. This is compounded by the lack of time structure in the extracted beam, as is typically required by the high-energy physics experiments, and the difficulty in accurately calibrating D.C. intensity monitors in the extraction line at count rates of ~ 10¹³ Hz. As a result, it is common for the extraction inefficiency to be measured by calibrating the beam loss signal induced by the slow extraction process itself. In this paper, measurements of the extraction efficiency performed at the CERN Super Proton Synchrotron for the third-integer resonant slow extraction of 400 GeV protons over recent years will be presented and compared to expectation from simulation. The technique employed will be discussed along with its limitations and an outlook towards a future online extraction efficiency monitoring system will be given.
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TUPAF055	Progress Toward a Dynamic Extraction Bump for Slow Extraction in the CERN SPS	simulation, alignment, septum, closed-orbit	838
	L.S. Stoel, M. Benedikt, M.A. Fraser, B. Goddard, J. Prieto, F.M. Velotti CERN, Geneva, Switzerland
	The possibility of reducing the angular spread of slow extracted particles with a time-dependent extraction bump at the CERN Super Proton Synchrotron (SPS) is under investigation. In order to create this so-called dynamic bump, two orthogonal knobs were designed to enable independent movements of the beam in position and angle at the upstream end of the electrostatic extraction septum (ES). With the present slow extraction scheme, simulations show that the use of a dynamic bump can reduce the angular spread at the ES by roughly a factor two and reduce beam loss on the ES. A reduction in the angular spread is also a prerequisite to exploit the full potential of other loss reduction techniques being considered for implementation at the SPS, like the active or passive diffusers planned for installation upstream of the ES in 2018. In this paper, the simulated loss reduction with a dynamic bump alone or in combination with other loss reduction techniques will be assessed, the first beam-based tests of the dynamic bump presented, the details of its implementation examined and its potential for future operation at the SPS discussed.
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TUPAF058	Optimization of the FCC-hh Beam Extraction System Regarding Failure Avoidance and Mitigation	kicker, hardware, collider, septum	850
	E. Renner, M.J. Barnes, W. Bartmann, F. Burkart, E. Carlier, L. Ducimetière, B. Goddard, T. Kramer, A. Lechner, N. Magnin, V. Senaj, J.A. Uythoven, P. Van Trappen, C. Wiesner CERN, Geneva, Switzerland
	A core part of the Future Circular Collider (FCC) study is a high energy hadron-hadron collider with a circumference of nearly 100~km and a center of mass beam energy of 100~TeV. The energy stored in one beam at top energy is 8.3~GJ, more than 20 times that of the LHC beams. Due to the large damage potential of the FCC-hh beam, the design of the beam extraction system is dominated by machine protection considerations and the requirement of avoiding any material damage in case of an asynchronous beam dump. Erratic operation of one or more extraction kickers is a main contributor to asynchronous beam dumps. The presented study shows ways to reduce the probability and mitigate the impact of erratic kicker switching. Key proposals to achieve this include layout considerations, different hardware options and alternative reaction strategies in case of erratic extraction kicker occurrence. Based on these concepts, different solutions are evaluated and an optimized design for the FCC-hh extraction system is proposed.
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TUPAF060	Injection and Dump Systems for a 13.5 TeV Hadron Synchrotron HE-LHC	kicker, injection, septum, experiment	858
	W. Bartmann, M.J. Barnes, L. Ducimetière, B. Goddard, M. Hofer, T. Kramer, A. Lechner, E. Renner, A. Sanz Ull, V. Senaj, L.S. Stoel, C. Wiesner CERN, Geneva, Switzerland
	One option for a future circular collider at CERN is to build a 13.5 TeV hadron synchrotron, or High Energy LHC (HE-LHC) in the LHC tunnel. Injection and dump systems will have to be upgraded to cope with the higher beam rigidity and increased damage potential of the beam. The required modifications of the beam transfer hardware are highlighted in view of technology advancements in the field of kicker switch technology. An optimised straight section optics is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF060
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TUPAF061	Use of a Massless Septum to Increase Slow-Extraction Efficiency	septum, sextupole, simulation, resonance	862
	K. Brunner, M.A. Fraser, B. Goddard, L.S. Stoel, C. Wiesner CERN, Geneva, Switzerland D. Barna Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
	The Super Proton Synchrotron (SPS) at CERN provides slow-extracted beam for Fixed Target experiments in the North Area. For the higher extracted beam intensities requested by future experimental proposals, beam-loss induced activation will be one of the limiting factors for the availability of such a facility. In this paper, we present and discuss the concept of using a massless septum magnet to increase the extraction efficiency and decrease losses caused by protons scattering on the electrostatic-septa wires.
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TUPAF081	Measurements and Simulations of the Spill Quality of Slowly Extracted Beams from the SIS-18 Synchrotron	sextupole, synchrotron, resonance, experiment	924
	S. Sorge, P. Forck, R. Singh GSI, Darmstadt, Germany
	In this contribution, results of recent measurements of the spill structure of slowly extracted beams out of the GSI heavy ion synchrotron SIS-18 are presented and compared to results of simulations. Aim of the study is the determination of spill structures at several kHz which arise from ripples in the fields of the accelerator magnets due to imperfections of the magnets' power supplies. The goal of the study is to understand how the ripple is transferred from the magnets to the spill and to find possible ways for spill smoothing. For this purpose a comprehensive simulation model for slow extraction is in preparation which will be validated with beam-based measurements.
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TUPAL018	Pulse-by-Pulse Switching of Operational Parameters in J-PARC 3-GeV RCS	emittance, operation, injection, betatron	1041
	H. Hotchi, H. Harada, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, Y. Watanabe, M. Yoshimoto JAEA/J-PARC, Tokai-mura, Japan
	J-PARC 3-GeV RCS (rapid cycling synchrotron) provides a high-power beam both to MLF (materials and life science experimental facility) and MR (main ring synchrotron) by switching the beam destination pulse by pulse. The beam properties required from MLF and MR are different; MLF needs a wide-emittance beam with less charge density, while MR requires a low-emittance beam with less beam halo. To meet the antithetic requirements while keeping beam loss at permissible levels, RCS has recently initiated pulse-by-pulse switching of operational parameters (betatron tune, chromaticity, painting emittance, etc.). This paper presents the recent efforts toward the performance upgrade of RCS while discussing the related beam dynamics issues.
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TUPAL027	Design of Multi-MW Rapid Cycling Synchrotron for Accelerator Driven Transmutation System	lattice, acceleration, proton, synchrotron	1057
	Y. Fuwa Kyoto ICR, Uji, Kyoto, Japan N. Amemiya Kyoto University, Kyoto, Japan Y. Ishi, Y. Kuriyama, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan
	For the practical application of Accelerator Driven System (ADS) that reduces the harmfulness of radioactive waste by transmutation, we are studying the development of a compact accelerator using a synchrotron as an accelerator capable of supplying a stable proton beam to a nuclear reactor. In this plan, we aim to realize down-sizing and high reliability by adopting an alternating high temperature superconducting magnet and a high repetition synchrotron applying resonant beam extraction. In this presentation we report the basic design of the optical system and beam acceleration sequence of this synchrotron.
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TUPAL036	Slow Extraction Techniques at the Marburg Ion-Beam Therapy Centre	synchrotron, simulation, controls, resonance	1084
	C. Krantz, T. Fischer, Th. Haberer, B. Kroeck, U. Scheeler, A. Weber, M. Witt MIT, Marburg, Germany R. Cee, F. Faber, E. Feldmeier, M. Galonska, Th. Haberer, A. Peters, S. Scheloske, C. Schömers HIT, Heidelberg, Germany F. Faber Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
	The Marburg Ion-Beam Therapy Centre offers hadron therapy using proton and carbon beams. The accelerator is based on a 65-m ion synchrotron by Danfysik/Siemens Healthcare. Beam extraction from the synchrotron is driven by a transverse RF knock-out (KO) system featuring Dynamic Intensity Control (DIC) of the spill. DIC allows modulation of the extraction rate by factors up to 30 on millisecond time scales. A fast response of the system to the variable intensity set-point can be obtained by careful adjustment of the RF-KO spectrum relative to the machine tune. Tracking simulations of the extraction phase have been conducted to refine that behaviour. Presently, we investigate how fast machine tune shifts, induced by an air-core quadrupole lens, can be used as a way to further improve the spill quality.
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TUPAL059	Commissioning of Shanghai Advance Proton Therapy	proton, MMI, dipole, injection	1151
	M.Z. Zhang, D.M. Li, K. Wang, Q.L. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China X.C. Xie Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People's Republic of China
	Shanghai advance proton therapy (SAPT) is a dedicate facility for cancer treatment. The commissioning of the accelerator started at the end of April 2017, and the proton beam has been already transported to the treatment room. This paper shows the commissioning results of synchrotron and transport line.
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TUPAL062	Recent Developments for Cyclotron Extraction Foils at TRIUMF	electron, cyclotron, simulation, TRIUMF	1159
	Y. Bylinskii, R.A. Baartman, P.E. Dirksen, Y.-N. Rao, V.A. Verzilov TRIUMF, Vancouver, Canada
	Funding: Funded under a contribution agreement with NRC (National Research Council Canada). The TRIUMF 500 MeV H− cyclotron employs stripping foils to extract multiple beams for different experimental programs. The upgrades in foil material and foil holders lead to significant improvements in beam quality and foil life time, as well as reduction of Be-7 contamination originated in the foils. Thus, an accumulated beam charge extracted with a single foil increased from ~60 mA·hours to more than 500 mA·hours. A key role that lead to these advances was an understanding of the foil heating mechanism, major contribution to which is paid by the power deposition from electrons stripped by the foil. To further diminish this effect, we recently introduced a foil tilt from the vertical orientation that allows stripped electrons fast escape from the foil, well before losing their original momentum through the heat deposition. Other improvements were related to operational issues. Introduction of a "combo" foil consisting of wide portion and thin wire allowed both high and low intensity beam extraction without foils sacrifice. Deploying a wedge foil for extraction at 100 MeV helped reduction of beam intensity instabilities caused by beam vertical size and position fluctuations.
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TUZGBF3	Betatron Core Slow Extraction at CNAO	betatron, synchrotron, cavity, acceleration	1237
	L. Falbo, E. Bressi, S. Foglio, C. Priano CNAO Foundation, Milan, Italy
	CNAO is the only Italian hadrontherapy facility able to treat tumors with beams of protons and carbon ions. Beam is extracted with a momentum selection scheme in which beam enters the third order resonance driven by a betatron core. When irradiating a tumor, it is thought as divided in the longitudinal plane in several slices while each slice is divided in the transverse plane in several spots called voxels. Considering the dose uniformity that can be obtained during extraction, the machine must extract an average intensity related to the voxel that requires less dose. Therefore during a treatment, for some slices, a technique is needed to lower the extracted beam intensity with respect to the nominal one. A way to guarantee the correct average intensity according to the treatment planning requirements, is to introduce a mechanical filter (a degrader) that reduces the intensity of the accelerated particles. However this method used in the first treatments at CNAO showed some disadvantages and it has been replaced by what has been called the "dynamic betatron" method. The paper shows the implementations and the advantages of this method in the CNAO treatments.
	Slides TUZGBF3 [2.146 MB]
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TUPMF003	Dynamic Tuning of the APS-U Booster 5-cell Cavities	booster, cavity, resonance, coupling	1251
	G.J. Waldschmidt, M. Abliz, T.G. Berenc, D. Horan, U. Wienands ANL, Argonne, Illinois, USA
	The booster synchrotron for the APS-U is being upgraded to accommodate high-charge bunches, up to 20 nC, for extraction into the MBA lattice. The booster is required to operate at 85% efficiency in order to achieve bunch swap-out into the storage ring. In order to compensate for significant beam-loading effects as well as support a frequency ramp to achieve higher efficiency, a ferrite tuner is being considered to dynamically adjust the cavity frequency. A tuner design will be presented that spans 60 kHz and utilizes a low-loss YIG garnet similar to that used in the Recycler Ring at Fermilab.
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TUPMF039	Recommissioning of the Canadian Light Source Booster Synchrotron	booster, MMI, optics, injection	1338
	W.A. Wurtz, D. Bertwistle, L.O. Dallin, X. Shen, J.M. Vogt CLS, Saskatoon, Saskatchewan, Canada
	The Canadian Light Source booster synchrotron was originally commissioned in 2002 and has worked reliably for many years. However, the operating point was not the design operating point and the booster suffered from poor quantum lifetime at the extraction energy. The low quantum lifetime caused current loss of approximately 25% in the microseconds before extraction. We have recommissioned the booster using the design optics, and the current loss before extraction is now only 6%. In this paper, we discuss the measurements and simulations involved in our recommissioning work.
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TUPMF046	The Injection and Extraction Design of the Booster for the HEPS Project	injection, kicker, storage-ring, booster	1356
	Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu IHEP, Beijing, People's Republic of China
	The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.
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TUPMF062	Status of HEPS Booster Lattice Design and Physics Studies	booster, injection, lattice, storage-ring	1407
	Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, C. Meng, S.K. Tian, H.S. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) with an ul-tralow emittance is proposed to be built in Beijing, Chi-na. It will utilize a booster as its full energy injector. On-axis swap-out injection is chosen as the baseline injec-tion scheme for the storage ring. As required by the stor-age ring, a beam with a bunch charge up to 2.5 nC is needed to be injected in the booster. However, limited by the transverse mode coupling instability (TMCI), such a high bunch charge is challenging. To overcome this problem, a lattice with a considerable large momentum compaction factor is designed. This paper reports the lattice design and physics studies of the HEPS booster, including injection and extraction design, error studies, eddy current effects, collective effects, and so on.
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TUPML030	Optimisation of D- Ion Production in a Multicusp Ion Source	plasma, ion-source, electron, dipole	1609
	A.M. George, M.P. Dehnel, S.V. Melanson, D.E. Potkins D-Pace, Nelson, British Columbia, Canada N. Broderick University of Auckland, Auckland, New Zealand H.C. McDonald, C. Philpott BSL, Auckland, New Zealand
	D-Pace's multicusp ion source achieves high beam cur-rents for negative hydrogen ions in both the TRIUMF-licensed filament-powered ion source (~18 mA) and the University of Jyväskylä-licensed RF-powered ion source (~8 mA) [1]. It is well known that ion sources producing negative deuterium ions achieve lower beam currents compared to similar negative hydrogen ion sources and indeed we have found that negative deuterium ion beam currents in our sources are typically 1/3 that of negative hydrogen beam currents. The reasons behind this are not completely understood, but factors such as the magnetic field strength and the electron temperature are believed to play a major role and offer the potential for significant optimisation. In this paper, we look into the issues surrounding swapping of deuterium for hydrogen in our ion source by studying the properties of plasmas and extracted currents with different magnetic field strengths and gas flows.
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TUPML055	Beam Optics Designs of a Strecher Ring and a Transfer Line for J-PARC Slow Extraction	quadrupole, optics, sextupole, injection	1667
	M. Tomizawa, R. Muto, T. Ogitsu KEK, Ibaraki, Japan A. Konaka TRIUMF, Vancouver, Canada
	The J-PARC main ring (MR) provides 30 GeV high intensity beams for neutrino experimental facility (NU) by fast extraction and hadron experimental facility (HD) by slow extraction. It is a serious issue to ensure sufficient integrated proton number on target (POT) for each facility. A stretcher ring (ST) can solve this serious problem. A beam accelerated by the MR is transferred to the ST and is slowly extracted over several second. While the beam is slowly extracted in the ST, the MR can accelerate and deliver a beam to the NU. The ST is put above the MR and fitted in the MR tunnel. Arc sections in the ST consist of superconducting combined function magnets (dipole, quadrupole and sextupole components), and separated function quadruple and sextupole magnets (hybrid lattice). A 30 GeV beam transfer line (BT) from the MR to the ST uses superconducting combined magnets with dipole and quadrupole functions to shorten the BT. The transferred beam is injected into an arc section in the ST. The adoption of the superconducting magnets in the ST and the BT saves operation cost drastically. Beam optics designs for the ST and the BT will be described in this paper.
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TUPML076	Installation, Commissioning and Characterization of EBIS-SC as a Short Pulsed Proton Source at KOMAC	electron, proton, MMI, neutron	1721
	S. Lee, Y.-S. Cho, H.S. Kim, H.-J. Kwon Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
	Funding: This work has been supported through KOMAC operation fund of KAERI by MSIT (Ministry of Science and ICT) Neutron source is applicable to various fields in basic/applied science and industries. There are several neutron sources in the world such LENS, SNS, J-PARC, ISIS and ESS either for short or long pulsed neutron. At Korea Multipurpose Accelerator Complex (KOMAC), to provide wide ranges of research opportunities to beam user, a 100 MeV proton linac based pulsed neutron source is planned for both long and short pulses of neutron source. Currently, the 100 MeV proton linac is operational with a 2 ms long pulsed proton injector, i.e. a microwave ion source. We will upgrade our injector by combining the already existing microwave ion source with a EBIS-SC (Superconducting Electron Beam Ion Source from Dreebit GmbH) for short pulses (< 1 us) of proton. This planned injector will work one at the time and provide long/short pulses of accelerated proton hitting a target to emit correspondingly long/short neutron pulses. Main modification on the proton injector is the EBIS-SC, so in this paper we report the installation, and commission of the EBIS-SC test bench at KOMAC. And the characterization of the EBIS-SC is described in detail.
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WEPAF007	A Scheme for Asynchronous Operation of the APS-U Booster Synchrotron	booster, injection, storage-ring, timing	1823
	U. Wienands, T.G. Berenc, T. Fors, F. Lenkszus, N. Sereno, G.J. Waldschmidt ANL, Argonne, Illinois, USA
	Funding: Work supported by US DOE The APS-U 6-GeV MBA storage ring will have 42 pm beam emittance and relatively tight acceptance. This requires limiting the beam emittance out of the Booster synchrotron which is achieved by operating the Booster off-momentum, thus manipulating the damping partitions. However, the much higher charge for the APS-U strongly favors injecting on momentum into the Booster for maximum acceptance. An rf-frequency ramping scheme is proposed to allow injecting on momentum and then moving the beam off momentum. The ramp is adjusted from cycle to cycle to vary the total time taken by the beam from injection to extraction, thus aligning the Booster bunch with any chosen MBA storage ring bucket. The two rf systems will not be locked at any time of the cycle. The proposed scheme is compatible with the existing synchronization of the APS injector cycle to the 60-Hz line voltage which induces a variation in the start time of the acceleration cycle. The scheme removes the need to realign the Booster ring for total path length while optimizing its operation for high charge acceleration. A ferrite tuner is being considered for dynamic tuning of the rf cavities.
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WEPAF063	RF Manipulations for Special LHC-Type Beams in the CERN PS	emittance, brightness, flattop, cavity	1971
	H. Damerau, S. Hancock, A. Lasheen, D. Perrelet CERN, Geneva, Switzerland
	Beams with special longitudinal characteristics for the Large Hadron Collider (LHC) have been produced in the Proton Synchrotron (PS) and CERN. The flexibility of its RF systems consisting of in total 25 RF cavities at frequencies from 400 kHz to 200 MHz allows a variety of longitudinal beam manipulations. In particular the main RF system is split into three independent groups tunable from 2.8 MHz to 10 MHz. It is used to merge, split and change the spacing between bunches by applying different voltage and phase programs to the three groups of cavities at different harmonic numbers simultaneously. The batch compression, merging and splitting (BCMS) process has been operationally used for LHC fillings since 2016. To mitigate issues with long bunch trains in the LHC in 2017, short gaps of four bunch positions have been introduced between mini-batches of eight bunches (8b4e). A higher brightness version resulting in four mini-batches per PS extraction has been delivered for luminosity production in the LHC. This paper summarizes the operational experience and indicates possible future RF manipulation schemes.
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WEPAF083	Distributed Optical Fiber Radiation Sensing at CERN	radiation, synchrotron, distributed, operation	2039
	G. Li Vecchi, M. Brugger, S. Danzeca, D. Di Francesca, R. Ferraro, Y. Kadi, O. Stein CERN, Geneva, Switzerland S. Girard Univ-Lyon Laboratoire H. Curien, UMR CNRS 5516, Saint Etienne, France
	The CERN's accelerator tunnels are associated with very complex mixed field radiation environments. Radiation degrades electronic components and directly affects their lifetimes causing failures that contribute to the machine downtime periods. In our contribution, we will report on the development and first employment of a Distributed Optical Fiber Radiation Sensor (DOFRS) at CERN. The most interesting feature of DOFRS technology is to provide an online and spatially distributed map of the dose levels in large machines with spatial resolution of the order of one meter. This fiber based dose sensor will provide valuable information in addition to the currently installed active and passive dosimeters. After demonstrating the working principle of DOFRS, the first operational prototype was installed in the Proton Synchrotron Booster during last 2016/17 end-of-the-year technical stop. The DOFRS has been acquiring data successfully since the beginning of 2017 operations. The performances that were achieved by the first prototype will be discussed in the final contribution. The DOFRS measurements will also be bench-marked to the results provided by other punctual dosimeters. I. Toccafondo et al., 'Distributed Optical Fiber Radiation Sensing in a Mixed-Field Radiation Environment at CERN,' J. Lightw. Technol. 35, 3303, 3310, 2017.
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WEPAK007	Slow Extraction Spill Characterization From Micro to Milli-Second Scale	power-supply, resonance, experiment, betatron	2095
	R. Singh, P. Boutachkov, P. Forck, S. Sorge, H. Welker GSI, Darmstadt, Germany
	This contribution deals with the topic of slow extraction spill quality characterization based on the measurements performed at GSI SIS-18. The sensitivity of the spill to power supply ripples are studied by introducing external ripples. An estimate of sources of inherent power supply ripples along with ripple magnitude are thus obtained. Spill characterization in time and frequency domain are discussed and exemplified by a typical spill and the differences from an ideal or Poisson spill. An appropriate spill characterization aims to provide a suitable abstraction for communication about the spill quality requirements between accelerator operations and users.
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WEPAL019	A Novel Field Cage Design for the CPS IPM and Systematic Errors in Beam Size and Emittance	electron, detector, cathode, emittance	2193
	K. Satou J-PARC, KEK & JAEA, Ibaraki-ken, Japan D. Bodart, S. Levasseur, G. Schneider, J.W. Storey CERN, Geneva, Switzerland M. Sapinski GSI, Darmstadt, Germany
	An ionization profile monitor has been recently installed in the CERN proton synchrotron. We design a novel and simple structure field cage that suppresses the secondary electrons that are induced by the ionized ions. We discuss a field cage design, and the systematic error on the basis of beam size and emittance, considering the non-uniformity of the fields, the space-charge effect of the beam, and the lattice parameter errors.
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WEPAL025	Development of a Low-Latency, High-Precision, Beam-Based Feedback System Based on Cavity BPMs at the KEK ATF2	feedback, cavity, dipole, kicker	2212
	R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, C. Perry JAI, Oxford, United Kingdom
	A low-latency, intra-train feedback system employing cavity beam position monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at KEK. The feedback system can be operated with either position information from a single BPM to provide local beam stabilisation, or by using position information from two BPMs to stabilise the beam at an intermediate location. The correction is implemented using a stripline kicker and a custom power amplifier, with the feedback calculations being performed on a digital board built around a Field Programmable Gate Array (FPGA). The addition of indium sealing to the BPMs to increase the cavities' Q-values has led to improvements to the BPM system resolution, with current measurements of the resolution of order 20 nm. The feedback performance was tested with beam trains of two bunches, separated by 280 ns and with a charge of ~1 nC. For single- (two-)BPM feedback, stabilisation of the beam has been demonstrated to below 50 nm (41 nm). Ongoing work to improve the feedback performance further will be discussed.
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WEPAL033	Development of Real-Time Mass Analysis System with Permanent Magnet for Ion Beam	ion-source, permanent-magnet, ECR, simulation	2236
	Y. Takeuchi, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan
	In order to analyze time variation of the ion species in a pulse, we are developing a mass analysis system that has multiple collector electrodes to detect several ion species simultaneously. Strong permanent magnets can generate 1T magnetic field and the size of the analyzing magnet system can be compact. The detected signals are scanned by a fast multiplexer. The scanning rate is 2 MHz, so that all electrode signals of the 16 channels are scanned in 8 μs period. In this paper, details of the design of the analysis system, and preliminary beam extraction test results with prototype of the system are described.
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WEPAL036	Implementation of CSNS RCS Beam Injection and Extraction Modes in Timing System	injection, timing, linac, kicker	2247
	P. Zhu, M.Y. Huang, D.P. Jin, G. Lei, G.L. Xu, Y.L. Zhang IHEP, Beijing, People's Republic of China L. Wang CSNS, Guangdong Province, People's Republic of China
	Funding: Institute of High Energy Physics， Chinese Academy of Sciences, Beijing 100049, China; Dong guan Neutron Science Center, Dong guan 523803, China Based on the physical design of the accelerator and the demand of the beam research, we designed four RCS beam injection modes and two RCS beam extraction modes, each of which corresponds to a series of specific timing for the accelerator. RCS beam injection and extraction modes are implemented on "VME + customized boards" hardware platform. In this paper, we will introduce the design and implementation of RCS beam injection and extraction modes as well as the RCS timing requirements and implementation in detail.
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WEPMF020	Pulsed Systems for eRHIC Beam Injection and Extraction	injection, kicker, storage-ring, electron	2410
	W. Zhang, M. Blaskiewicz, A. Hershcovitch, C.J. Liaw, H. Lovelace III, M. Mapes, G.T. McIntyre, J.-L. Mi, C. Montag, C. Pai, V. Ptitsyn, J. Sandberg, N. Tsoupas, J.E. Tuozzolo, G.M. Wang, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu 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 electron-ion collider eRHIC requires a variety of kickers and septa for injection and extraction of beams throughout the entire collider complex. We plan to use pulsed systems for beam injection and extraction in Electron RCS, Electron Storage Ring, and Hadron ring. In this paper, we describe the pulsed systems required for beam transfer in the eRHIC Ring-Ring Pre-conceptual Design. We will outline the parameter ranges, technology choices, and opportunities for research and development in pulsed power technology.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF020
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WEPMF077	Demonstration of Feasibility of the CLIC Damping Ring Extraction Kicker Modulators	kicker, flattop, damping, collider	2557
	J. Holma, M.J. Barnes, A. Ferrero Colomo CERN, Geneva, Switzerland
	The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. Specifications for the electromagnetic field pulses require that the modulator produce pulses of 160 or 900 ns flattop duration, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to an ideal waveform. Inductive adder topology has been chosen for the pulse modulators where the output waveform can be adjusted by applying analogue modulation methods. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed and built, and they are being tested at CERN. These modulators will be tested with a prototype stripline kicker, installed in a beamline at ALBA Synchrotron Light Source in Spain. The results of the laboratory tests and measurements are presented.
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WEPMF087	LHC Injectors Upgrade Project: Outlook of the Modifications to the Super Proton Synchrotron (SPS) Vacuum System and Impact on the Operation of the Carbon-Coated Vacuum Chambers	vacuum, impedance, experiment, proton	2589
	C. Pasquino, G. Bregliozzi, P. Chiggiato, P. Cruikshank, A. Farricker, A. Harrison, J. Perez Espinos, J.A.F. Somoza, M. Taborelli, C. Vollinger CERN, Geneva, Switzerland
	Aiming at doubling the beam intensity and reducing the beam emittance, significant modifications of the LHC and its injector chain will take place during Long Shutdown 2 (LS2), starting from 2019. The LIU project (LHC Injector Upgrade), in the specific, touches Linac4, the Proton Synchrotron Booster (PSB), the Proton Synchrotron (PS), the Super Proton Synchrotron (SPS) as well as the heavy ion chain. During LS2, important changes will take place mainly in the Long Straight Sections of the SPS to host a newly conceived dumping system, upgraded RF cavities and upgraded extraction channels. Additionally, the vacuum chambers of the main bending and focusing magnets as well as vacuum drifts will be coated with amorphous carbon in order to reduce the dynamic pressure effects induced by multipacting. The modifications to the different vacuum sectors will be described in details as well as the impact on operation of amorphous carbon coated sectors that have been already deposited.
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WEPML036	Truncated Cosine Theta Magnet and the Applications	septum, injection, collider, heavy-ion	2772
	K. Sugita, E.S. Fischer, P.J. Spiller GSI, Darmstadt, Germany
	Typically septum magnets are designed with a combination of a C-shape iron yoke and a copper cable. Due to leakage of a magnetic field at a circulating beam passing through a saturated iron area, high field septum magnets with this concept is not feasible. Thus, this conventional design approach is limited magnetic field strength below 2 Tesla. For high energy machines, like SIS300 at FAIR or FCC at CERN, high field septum magnets are required to shorten the injection and extraction branch lines. Recently superconducting magnets, which enable to reduce the size of a building, are being introduced to medical accelerators. However, even if bending magnets are replaced by high field magnets, long straight sections, which is partly composed by a conventional septum magnet, remain. By introducing high field septum magnets, more compact accelerator can be designed. To get over the limitation of 2 Tesla, a novel concept of a septum magnet generating high magnetic field has been developed and design studies are ongoing. By using superconducting technology, a septum magnet can be designed to generate more than 2 Tesla. We present the concept and various application for the accelerators.
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WEPML064	Design of the Trim Coil for the Superconducting Cyclotron Extraction	cyclotron, resonance, controls, flattop	2840
	L.G. Zhang, K. Fan, S. Hu, Z.Y. Mei, Z.J. Zeng HUST, Wuhan, People's Republic of China
	A proton therapy system is being developed at Huazhong university of science and technology (HUST). A 250 MeV superconducting cyclotron with an average magnetic filed of 3.1 T in the extraction region is selected to reduce the machine size, which creates difficulties for beam extraction because of the small turn separation of the beam orbits in the extraction region. To obtain high extraction efficiency, a carefully controlled magnetic perturbation is introduced to excite resonance when beam passes through the νr =1 resonance. The first-order perturbation in the magnetic field is generated by trim coils within confined regions. The profile of the trim coil and the resultant perturbation fields are optimized iteratively with orbit tracking. Simulation shows that sufficient turn separation can be obtained with the proper setting of trim coils.
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THYGBF1	High Power Beam Operation of the J-PARC RCS and MR	operation, emittance, quadrupole, betatron	2938
	Y. Sato KEK, Ibaraki, Japan
	This invited talk presents the most recent status of improving J-PARC main ring (MR) beam operation together with the rapid cycling synchrotron (RCS) effort. The RCS has optimized the beam performance for the MR injection as well as the muon and neutron targets, where each requires different emittance and beam halo size. The MR has two extraction modes; fast extraction (FX) for the long baseline neutrino oscillation experiment, T2K, and slow extraction (SX) for experiments in the hadron experimental facility. At present, achieved beam intensities are 2.4·10¹⁴ protons per pulse (ppp) with cycle time 2.48 s (470 kW) in the FX mode and 5.10¹³ ppp with cycle time 5.52 s (44 kW) in the SX mode. For the FX operation, recent improvements are settings of new betatron tune, corrections of resonances near the betatron tune, and adopting 2nd harmonic rf voltage to reduce space charge effect. Beam instabilities have been suppressed with controlling chromaticity correction and transverse feedback systems. For the SX mode, a dynamic bump scheme for reducing extracted beam loss is successfully adopted. A high extraction efficiency of 99.5 % is achieved at the 44 kW beam operation.
	Slides THYGBF1 [6.664 MB]
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THPAF080	SIS100 Beam Dynamics Challenges Related to the Magnet System	dipole, quadrupole, resonance, sextupole	3172
	V. Kornilov, O. Boine-Frankenheim, V. Chetvertkova, S. Sorge, P.J. Spiller GSI, Darmstadt, Germany
	The SIS100 synchrotron is the central accelerator of the upcoming FAIR project at GSI, Darmstadt, Germany. The major challenges of the future operation are related to high-intensity, low beam loss operation for a wide range of ion species and charge states, for different operational cycles and extraction schemes. The magnet system consists of 108 dipole, 166 quadrupole and additional correction superconducting superferric magnets. The magnets are presently under production and testing, with detailed measurements of the magnetic field imperfections. This results in the construction of a complete database for the SIS100 magnet system. We analyse implications of the magnetic field imperfections for the single-particle stability, space charge induced tune-shifts and resonance crossing for the different SIS100 operation modi. Resonance compensation and magnet sorting schemes are discussed as possible measures.
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THPAK007	Beam Extraction from TR24 Cyclotron at IPHC	cyclotron, betatron, closed-orbit, emittance	3218
	N.Yu. Kazarinov, I.A. Ivanenko JINR, Dubna, Moscow Region, Russia F.R. Osswald IPHC, Strasbourg Cedex 2, France
	The CYRCé cyclotron is used at IPHC (Institut Pluridisciplinaire Hubert Curien) for the production of radio-isotopes for diagnostics, medical treatments and fundamental research in radiobiology. The TR24 cyclotron manufactured and commercialized by ACSI delivers a 16-25 MeV proton beam with intensity from few nA up to 500 microA. The TR24 is a separated-sector isochronous cyclotron with normal-conducting magnet and stripper foil. It is a challenge to fit the high intensity proton beam used for target irradiation to radiobiology and analytical applications due to requirements on beam quality and energy resolution. Field distribution in the region of the extraction performed with OPERA 3D as well as beam dynamics related with stripping are analysed. 3D calculation model and hypothesis about geometry and beam are described. Our goal is to evaluate the extraction efficiency and the beam characteristics in the focusing plane outside the cyclotron which will serve as inputs for the design of future beam lines and enable beam matching conditions. Therefore, different issues are discussed: energy dispersion, transverse dynamics and orbit separation.
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THPAK019	Beam Dynamics of the First Beams for IFMIF-EVEDA RFQ Commissioning	rfq, proton, emittance, solenoid	3246
	L. Bellan, C. Baltador, M. Comunian, E. Fagotti, F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy T. Akagi KEK, Ibaraki, Japan B. Bolzon, N. Chauvin CEA/DSM/IRFU, France H. Dzitko F4E, Germany K. Kondo, M. Sugimoto QST, Aomori, Japan I. Podadera CIEMAT, Madrid, Spain F. Scantamburlo IFMIF/EVEDA, Rokkasho, Japan
	The installation of the IFMIF-EVEDA RFQ, MEBT, LEBT, source and beam dump was completed in September 2017. The beam dynamics of the first beams for the IFMIF-EVEDA RFQ commissioning is presented. Moreover, a proposal for the CW RFQ steady state commissioning is shown, with a focus on the beam dynamics challenges of the beam transport after the RFQ.
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THPAK023	Proposal for Using DAΦNE as Pulse Stretcher for the Linac Positron Beam	septum, linac, positron, pulse-stretcher	3258
	S. Guiducci, D. Alesini, M.E. Biagini, S. Bilanishvili, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, D.G.C. Di Giulio, L.G. Foggetta, A. Gallo, A. Ghigo, L. Kankadze, C. Milardi, R. Ricci, U. Rotundo, L. Sabbatini, M. Serio, A. Stella INFN/LNF, Frascati (Roma), Italy P. Valente INFN-Roma, Roma, Italy
	The PADME experiment* proposes a search for the dark photon (A') in the e⁺e⁻ -> gamma A' process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Frascati National Laboratory. The linac could provide a number of positrons as high as 10⁹/pulse in a 200 ns pulse but the number of positrons for PADME is limited below 10⁵/pulse in order to keep the pile-up probability in the calorimeter low enough. The PADME experiment is indeed limited by the low duty factor (10e-5=200ns/20ms). An alternative proposal to use the DAΦNE positron ring as a linac pulse stretcher, by injecting each pulse into the ring and extracting it by a slow resonant extraction using the m/3 resonance, is described in this paper. This allows to distribute the positrons of a linac pulse in a much longer pulse (0.2 - 0.5 ms) increasing the duty factor up to ~ 2%. The required modifications of the DAΦNE positron transfer line and main ring are presented. A dedicate lattice for the ring has been designed and tracking of the positrons in the ring has been performed to optimize extraction parameters and give a preliminary estimate of the extracted beam characteristics. * M. Raggi et al., EPJ Web Conf. 96 (2015) 01025
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THPAK028	Beam Dynamics Simulations in the Dubna SC202 Superconducting Cyclotron for Hadron Therapy	cyclotron, proton, simulation, cavity	3270
	O. Karamyshev, G.A. Karamysheva, D.V. Popov, G. Shirkov, S.G. Shirkov JINR, Dubna, Moscow Region, Russia V. Malinin JINR/DLNP, Dubna, Moscow region, Russia
	In 2015 the joint project JINR (Dubna, Russia) - ASIPP (Hefei, China) on design and construction of supercon-ducting proton cyclotron SC202 was started. Two cyclo-trons are planned to be manufactured in China, according to the Collaboration Agreement between JINR and ASIPP. The first cyclotron will be used for proton therapy in Hefei and the second one will replace the Phasotron in the research and treatment program on proton therapy in Dubna. New schema of extraction system and results of beam acceleration and extraction simulations for Dubna cyclotron are presented.
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THPAK034	Practical Betatron Tune Behavior During Acceleration in Scaling FFAG Rings at KURNS	booster, acceleration, betatron, proton	3287
	Y. Ishi, Y. Fuwa, Y. Kuriyama, Y. Mori, H. Okita, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan J.-B. Lagrange Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	In scaling FFAG* accelerators, ideally, betatron tunes are fixed for each closed orbit concerned with the certain beam energy. Therefore, they should not vary during the acceleration. However, it is not the case since practical implementations of the magnetic field can not provide perfect scaling conditions. There are two types of radial scaling FFAG ring at Kyoto University Research Reactor Institute: one has no return yokes so called 'yoke free type' adopted by MAIN RING which has a large tune variations causing non negligible beam losses; the other has return yokes and filed clamps adopted by BOOSTER RING which has smaller tune variations compared with MAIN RING. We report the tune measurements and calculations based on 3-d magnetic field calculations about these two types of ring and discuss the scaling conditions in FFAG accelerators. FFAG : FFAG stands for fixed filed alternating gradient. It describes one the focusing scheme in the circular accelerator.*
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THPAK105	Construction Progress of Two Superconducting Cyclotrons for Proton Therapy and Proton Irradiation at CIAE	cyclotron, proton, cavity, controls	3477
	T.J. Zhang, S. An, H.R. Cai, L.C. Cao, X.L. Cao, T. Cui, X.L. Fu, T. Ge, P.F. Gong, F.P. Guan, L.L. Guan, S.G. Hou, B. Ji, X.L. Jia, M. Li, X.L. Li, Y.Q. Li, J. Lin, J.Y. Liu, X.T. Lu, Y.L. Lv, C. Wang, F. Wang, F. Wang, L. Wang, J.Y. Wei, S.M. Wei, J.S. Xing, G. Yang, J.J. Yang, M. Yin, Z.G. Yin, D.S. Zhang, S.P. Zhang, X. Zhen CIAE, Beijing, People's Republic of China K. Fong TRIUMF, Vancouver, Canada
	Funding: Supported partly by the National Natural Science Foundation of China (Grant No. 11375273 and 11475269) and by the Ministry of Science and Technology under Grant 2016YFC0105300. There are very strong demand for mid-energy of proton machine recent years due to the surging cancer patients and fast progress of the space science in China. For the applications of proton therapy and proton irradiation, the energy range of proton beam usually is from 200 MeV to 250 MeV, or even higher for astronavigation. Based on the R&D starting from 2009, two construction projects of 230 MeV and 250 MeV superconducting cyclotron, which have been implemented recently at China Institute of Atomic Energy(CIAE). That was started in Jan 2015 for the 230 MeV machine, for the program of proton therapy and space science launched by China National Nuclear Corporation (CNNC), and in Jan 2016 for the 250 MeV machine, for the program of proton therapy launched by the Ministry of Science and Technology of China (MOST). In this paper, the designs for the two SC cyclotrons and their key components, including the main magnet, SC coils, RF system, internal ion source and central region, extraction system, etc, and the construction progress of the machines will be presented.
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THPAK111	Envelope Calculations on the Ion Beam Injection and Extraction of CANREB EBIS	electron, simulation, injection, TRIUMF	3496
	M.H. Pereira-Wilson UW/Physics, Waterloo, Ontario, Canada R.A. Baartman, S. Saminathan TRIUMF, Vancouver, Canada
	An electron beam ion source (EBIS) is being developed as a charge state breeder for the production of highly charged ions in the CANREB (CANadian Rare isotope facility with Electron Beam ion source) project at TRIUMF. The multiple tunable electrodes of the EBIS, coupled with the necessity of directing both an electron beam and an ion beam of varying charge, impose a challenging task for the optimization of the beam optics. With this in mind, beam envelope simulations have been performed to determine the acceptance of the EBIS and the emittance of the extracted ion beam. The electric field of the different EBIS electrodes were modelled using finite element analysis software and the envelope simulations were executed using beam envelope code TRANSOPTR. Preliminary results show envelope calculation as a viable candidate for tuning the injection and extraction optics of the EBIS.
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THPMF013	The Stripline Kicker Prototype for the CLIC Damping Rings at ALBA: Installation, Commissioning and Beam Characterisation	kicker, storage-ring, synchrotron, impedance	4062
	M. Pont, N. Ayala, M. Carlà, T.F.G. Günzel, U. Iriso, Z. Martí, R. Monge, A. Olmos, F. Pérez, M. Quispe ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain M.J. Barnes, C. Belver-Aguilar, Y. Papaphilippou CERN, Geneva, Switzerland
	The extraction system for the CLIC Damping Rings has very tight specifications. Therefore a full characterisation of the behaviour of the stripline kicker under conditions as close as possible to the expected working conditions will be very valuable. To that end the CLIC stripline has been installed in the ALBA Synchrotron Light Source and has been characterised with beam. Prior to its installation, the effect of the stripline kicker on the machine impedance has been assessed. The installation has required the design of an absorber to screen the stripline from synchrotron radiation and additional BPMs have been installed for a better kick angle determination. The commissioning of the stripline with beam has been performed following closely beam parameters, pressure and temperature. The studies with beam include the determination of the longitudinal and transverse impedance of the kicker, the field homogeneity when excited with a dc field and the field ripple when pulsed. This contribution reports on the first experience with the stripline kicker for the CLIC DR in the ALBA storage ring and presents the results of the initial beam characterisation. M. Carla et al., "Beam based impedance measurements of the CLIC stripline at ALBA", Proc. of IPAC'2017.
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THPMF052	The Swap-Out Injection Scheme for the High Energy Photon Source	injection, booster, storage-ring, kicker	4178
	Z. Duan, J. Chen, Y.Y. Guo, Y. Jiao, J.L. Li, Y.M. Peng, J.Q. Wang, N. Wang, G. Xu, H.S. Xu IHEP, Beijing, People's Republic of China
	Funding: Work supported by Natural Science Foundation of China (No.11605212). The on-axis swap-out scheme is a promising injection scheme for di raction-limited storage rings, since it only re- quires a rather small dynamic aperture and thus potentially allows a higher brightness compared to traditional o -axis injection schemes. However, a full charge injector is neces- sary for this scheme and its design can be nontrivial, in par- ticular to satisfy the large single bunch charge requirements in special lling patterns for timing experiments. In the High Energy Photon Source, we propose using the booster also as a high energy accumulator ring to recapture the spent bunches extracted from the storage ring, so as to relax the challenges in generation and acceleration of bunches with a high charge, and as a cost-e ective solution compared to building a dedicated full energy accumulator ring. In this paper, the beam dynamics issues of this scheme will be presented, trade-o s between the storage ring and booster beam parameters and hardware specifications will also be discussed.
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THPML080	Preliminary Results of a New High Brightness H⁻ Ion Source Developed at TRIUMF	emittance, ion-source, TRIUMF, high-voltage	4839
	K. Jayamanna, F. Ames, Y. Bylinskii, J.Y. Cheng, M. Lovera, M. Minato TRIUMF, Vancouver, Canada
	This paper describes the preliminary results of a high brightness ion source developed at TRIUMF, which is capable of producing a negative hydrogen ion beam (H⁻) of up to 5 mA of direct current. A 1.7 mm.mrad and 5 mm.mrad emittance(rms) is achieved for 500 uA and for 1 mA H-, respectively. Characteristics as well as a brief description regarding extraction issues of the source to date are also presented.
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MOPMF002

Pre-Booster Ring Considerations for the FCC e⁺e⁻ Injector

booster, emittance, damping, wiggler

83

O. Etisken
Ankara University, Faculty of Sciences, Ankara, Turkey
F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
A.K. Çiftçi
Izmir University of Economics, Balçova/Izmir, Turkey

The FCC-e⁺e⁻ injector complex needs to produce and to transport a high-intensity e⁺/e⁻ beam at a fast repetition rate for topping up the collider at its collision energy. Two different options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and a completely new ring. The purpose of this paper is to explore the needs and parameters of the existing SPS and the conceptual design of an alternative accelerator ring with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the basic parameters of both choices are established, including the optics design and layout updates. Consideration for non-linear dynamics optimization and the impact of intra beam scattering are also presented.

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MOPMF054

Comparison of Different Transverse Emittance Measurement Techniques in the Proton Synchrotron Booster

emittance, proton, optics, booster

232

G.P. Di Giovanni, S.C.P. Albright, V. Forte, M.A. Fraser, G. Guidoboni, B. Mikulec, F. Roncarolo, A. Santamaría García
CERN, Geneva, Switzerland

The measurement of the transverse emittance in an accelerator is a crucial parameter to evaluate the performance of the machine and to understand beam dynamics processes. In recent years, controlling and understanding the emittance became particularly relevant in the Proton Synchrotron Booster (PSB) at CERN as part of the LHC Injectors Upgrade (LIU). The LIU project is a necessary step to achieve the goals of the High-Luminosity LHC project. In this framework, an accurate and reliable emittance measurement of high brightness beams is mandatory to study the brightness reach of the LHC injectors. In the PSB there are two main instruments available for emittance measurements: wire scanners and secondary-emission (SEM) grids. In this paper emittance measurements performed during the 2017 physics run with these two systems are compared, taking into account various systematic error sources.

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MOPMF063

Asynchronous Beam Dump Tests at LHC

proton, beam-losses, quadrupole, operation

265

C. Wiesner, W. Bartmann, C. Bracco, E. Carlier, L. Ducimetière, M.I. Frankl, M.A. Fraser, B. Goddard, C. Heßler, T. Kramer, A. Lechner, N. Magnin, V. Senaj, D. Wollmann
CERN, Geneva, Switzerland

The detailed understanding of the beam-loss pattern in case of an asynchronous beam dump is essential for the safe operation of the future High Luminosity LHC (HL-LHC) with nearly twice the nominal LHC beam intensity, leading to correspondingly higher energy deposition on the protection elements. An asynchronous beam dump is provoked when the rise time of the extraction kickers is not synchronized to the 3 us long particle-free abort gap. Thus, particles that are not absorbed by dedicated protection elements can be lost on the machine aperture. Since asynchronous beam dumps are among the most critical failure cases of the LHC, experimental tests at low intensity are performed routinely. This paper reviews recent asynchronous beam dump tests performed in the LHC. It describes the test conditions, discusses the beam-loss behaviour and presents simulation and measurement results. In particular, it examines a test event from May 2016, which led to the quench of four superconducting magnets in the extraction region and which was studied by a dedicated beam experiment in December 2017.

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MOPMF070

High Voltage Design for the Electrostatic Septum for the Mu2e Beam Resonant Extraction

cathode, high-voltage, vacuum, simulation

289

M.L. Alvarez, C.C. Jensen, D.K. Morris, V.P. Nagaslaev, H. Pham, D.G. Tinsley
Fermilab, Batavia, Illinois, USA

Two electrostatic septa (ESS) are being designed for the slow extraction of 8GeV proton beam for the Mu2e experiment at Fermilab. Special attention is given to the high voltage components that affect the performance of the septa. The components under consideration are the high voltage (HV) feedthrough, cathode standoff (CS), and clearing electrode ceramic standoffs (CECS). Previous experience with similar HV systems at Fermilab was used to define the evaluation criteria of the design of the high voltage components. Using electric field simulation software, high E-field intensities on the components and integrated field strength along the surface of the dielectric material were minimized. Here we discuss the limitations found and improvements made based on those studies.

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MOPML021

Shorter Treatment Time by Intensity Modulation with a Betatron Core Extraction

betatron, proton, radiation, synchrotron

439

M. G. Pullia, E. Bressi, G.M.A. Calvi, M. Donetti, L. Falbo, S. Foglio, V. Lante, A. Parravicini, C. Priano, E. Rojatti, S. Savazzi, C. Viviani
CNAO Foundation, Pavia, Italy

The CNAO (National Center for Oncological Hadrontherapy) main accelerator is a synchrotron capable to accelerate carbon ions up to 400 MeV/u and protons up to 250 MeV. Three treatment rooms are available and are equipped with horizontal beam lines; one of the treatment rooms also features a vertical treatment line to allow additional treatment ports. All of the beamlines are equipped with an active beam scanning system for dose delivery. With such a dose distribution technique, particles are sent to different depths by changing the energy from the synchrotron and are moved transversally by means of two scanning magnets. The number of particles to be deposited in each position varies strongly within the same iso-energetic layer. Part of the dose needed in a given position is in fact delivered by particles directed to deeper layers. In order to maintain the required precision on the number of particles delivered to each spot, the intensity is reduced when spots that require low number of particles are present in a layer. A method to shorten the irradiation time based on variable intensity within the same layer is presented that works also with a betatron based extraction scheme.

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MOPML025

Slow Extraction Optimization at the MedAustron Ion Therapy Center: Implementation of Front End Acceleration and RF Knock Out

proton, acceleration, synchrotron, kicker

453

A. De Franco, L. Adler, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl
EBG MedAustron, Wr. Neustadt, Austria
L.C. Penescu
Abstract Landscapes, Montpellier, France

Funding: This project has received funding from the European Union's Horizon 2020 research and Innovation programme under the Marie Skłodowska-Curie grant agreement No 675265.
MedAustron is a synchrotron-based ion therapy center allowing tumour treatment with protons and other light ion species, in particular C⁶⁺. Commissioning of all fixed lines, two horizontal and one vertical, has been completed for protons and in parallel to the commissioning of a gantry and C⁶⁺, a facility upgrade study is progressing. The upgrade study encompasses the optimization of the slow extraction mechanism by employing the RF empty bucket channeling and RF Knock Out techniques. The former is a front end acceleration technique that suppress spill ripples, fundamental to safely operate the machine at the highest intensities. The latter is an alternative extraction technique which opens up interesting possibilities for fast beam energy and intensity modulations. In this work, we quantify spill smoothening effect achieved with the first and report the results of a feasibility study of the second using a Schottky monitor as a transverse kicker.

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MOPML035

Betatron Frequencies in Cotangential Trajectory Accelerator for Proton Beam Therapy

betatron, alignment, cyclotron, resonance

485

T. Aoki, F. Ebina, C. Hori, Y. Nakashima, T. Seki
Hitachi Ltd., Ibaraki-ken, Japan
T. Hae
Hitachi Ltd., Hitachi Research Laboratory, Ibaraki-ken, Japan

It is important that downsizing of an accelerator for spreading proton beam therapy. The synchrotron is the solution of accelerator of proton beam therapy system which can vary energy of extracted beam in the range of from 70 MeV to 235 MeV with a merit of requiring no energy selection system. In order to downsize accelerator with above merit, we suggested smaller variable energy accelerator which have cotangential trajectories. This new type accelerator is expected to realize variability of beam energy with static main magnetic field. One of technological problems of this new type accelerator is stability of betatron oscillation. We plan to utilize week focusing field as main magnetic field, which is decreasing on the radial direction outward and uniform in longitudinal direction, of this new type accelerator. We found the main magnetic field which realizes stable betaron oscillations in the range of from 70 MeV to 235 MeV as the result of estimating the betaron oscillations in this main field by numerical calculation. We report new type accelerator concept and results of analysis of betatron oscillation in cotangential trajectories.

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TUXGBF3

Reduction of the Kicker Impedance Maintaining the Performance of Present Kicker Magnet at RCS in J-PARC

kicker, impedance, simulation, synchrotron

616

Y. Shobuda, Y. Irie, T. Takayanagi, T. Togashi, K. Yamamoto, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The present kicker at RCS in J-PARC is designed to make a waveform by superposing the forward and backward currents from the power source to extract beams, so that one terminal of the kicker is shorted and the other one is open. On the other hand, the kicker impedance is the dominant source of the beam instability at the RCS. This report proposes a scheme to reduce the kicker impedance, maintaining the beneficial of the superposition of currents with the present kicker magnet.

Slides TUXGBF3 [9.947 MB]

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TUPAF004

Status of the MedAustron Beam Commissioning with Protons and Carbon Ions

MMI, proton, dipole, synchrotron

665

C. Kurfürst, L. Adler, A. De Franco, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl
EBG MedAustron, Wr. Neustadt, Austria
L.C. Penescu
Abstract Landscapes, Montpellier, France

MedAustron is a synchrotron-based Particle Therapy Accelerator located in Wiener Neustadt, Austria, which is delivering beams for medical treatment since end of 2016. The accelerator provides clinical proton beams in the energy range 62-252 MeV and is designed to provide carbon ions in the range 120-400 MeV/n to three ion therapy irradiation rooms IRs, including a room with a proton Gantry. Proton beams of up to 800 MeV will be provided to a fourth room dedicated to research. Presently, proton beams are delivered to the fixed horizontal beam lines of three rooms. Beam commissioning of the vertical beam line of the second IR is being completed and the beam line is in preparation for clinical treatment. Commissioning of the accelerator with carbon ions is advancing and first clinical beams have been sent to the IRs, while the preparation for the Gantry beam line is ongoing. A slow extraction 3rd order resonance method is used to extract particles from the synchrotron between 0.1-10 seconds to favor control of the delivered dose during clinical treatments. The main characteristics of the accelerator and results obtained during the latest commissioning activities are presented.

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TUPAF010

Empty Sweeping Bucket for Slow Extraction

resonance, acceleration, hadrontherapy, synchrotron

676

L. Falbo, E. Bressi, C. Priano
CNAO Foundation, Milan, Italy

The extraction process from a synchrotron is one of the most important aspects of an accelerator devoted to clinical purposes, like the hadrontherapy in which hadron beams are used to treat tumors. Indeed the quality of the dose delivered to the patient, in terms of dose uniformity and precision in the beam characteristics, is defined by the way in which the beam is extracted. The quality of the extracted beam (the so called spill) is strongly affected by the stability of the power supplies of the synchrotron magnets whose field stability creates a ripple in the intensity of the extracted beam itself. When it is not possible to improve the power supply stability, it is needed to apply some additional techniques in order to cure the spill ripple. At CNAO, the italian hadrontherapy facility, it has been thought to improve the Empty Bucket Channelling technique by using an energy-moving bucket instead of a stationary bucket. The paper shows the implementation, the advantages and the efficacy of this RF gymnastic, named 'Empty Sweeping Bucket'.

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TUPAF020

Performance of the CERN Low Energy Ion Ring (LEIR) with Xenon beams

injection, MMI, linac, controls

705

R. Alemany-Fernández, S.C.P. Albright, O. Andujar, M.E. Angoletta, J. Axensalva, H. Bartosik, G. Baud, N. Biancacci, M. Bozzolan, S. Cettour Cave, K. Cornelis, J. Dalla-Costa, M. Delrieux, A. Dworak, A. Findlay, F. Follin, A. Frassier, M. Gabriel, A. Guerrero, M. Haase, S. Hirlaender, S. Jensen, V. Kain, L.V. Kolbeck, Y. Le Borgne, D. Manglunki, O. Marqversen, S. Massot, D. Moreno Garcia, D.J.P. Nicosia, S. Pasinelli, L. Pereira, D. Perez, A. Rey, J.P. Ridewood, F. Roncarolo, A. Saá Hernández, R. Scrivens, O.G. Sveen, G. Tranquille, E. Veyrunes
CERN, Geneva, Switzerland

In 2017 the CERN Low Energy Ion Ring demonstrated once more the feasibility of injecting, accumulating, cooling and accelerating a new nuclei, 129Xe39 . The operation of this new ion species started at the beginning of March with the start up of the xenon ion source and the Linac3. Ten weeks later the beam arrived to the Low Energy Ion Ring (LEIR) triggering the start of several weeks of beam commissioning in view of providing the injector complex with Xenon beams for different experiments and a series of machine development experiments in LEIR. Two types of beams were setup, the so called EARLY beam, with a single injection into LEIR from Linac3, and the NOMINAL beam with up to seven injections. 2017 was as well an interesting year for LEIR because several improvements in the control system of the accelerator and in the beam instrumentation were done in view of increasing the machine reliability. This paper summarises the beam commissioning phase and all the improvements carried out during 2017.

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TUPAF032

Beam Transfer Line Design to the SPS Beam Dump Facility

target, proton, experiment, quadrupole

751

Y. Dutheil, J. Bauche, M. Calviani, L.A. Dougherty, M.A. Fraser, B. Goddard, C. Heßler, J. Kurdej, E. Lopez Sola
CERN, Geneva, Switzerland

Studies for the SPS Beam Dump Facility (BDF) are ongoing within the scope of the Physics Beyond Collider project. The BDF is a proposed fixed target facility to be installed in the SPS North Area, to accommodate the SHiP experiment (Search for Hidden Particles), which is most notably aiming at studying hidden sector particles. This experiment requires a high intensity slowly extracted 400 GeV proton beam with 4·10¹³ protons per 1 s spill to achieve 4·10¹⁹ protons on target per year. The extraction and transport scheme will make use of the first 600 m of the existing North Area extraction line. In this paper, we will present the design of the additional 600 m of transfer line towards BDF branching off from the existing line and discuss the detailed design of the BDF beam line, its components and optics. We present the latest results on the study and design of a new laminated Lambertson splitter magnet to provide fast switch between the current North Area experiments and the BDF. The latest specification of a dipole dilution system used to reduce the local peak power of the beam on the target is also presented.

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TUPAF033

Beam Optics Studies for BDF and for Tests of a Prototype Target

target, optics, emittance, proton

754

C. Heßler, M. Calviani, Y. Dutheil, M.A. Fraser, B. Goddard, V. Kain, E. Lopez Sola, F.M. Velotti
CERN, Geneva, Switzerland

Within the frame of the Physics Beyond Collider project a new fixed target facility at the SPS North Area, the so-called Beam Dump Facility (BDF), is under study. BDF requires a high intensity slowly extracted 400 GeV proton beam with 4·10¹³ protons per 1 s spill to achieve 4·10¹⁹ protons on target per year. This results in an exceptionally high average beam power of 355 kW on the target, which is a major challenge. To validate the target design, a test of a prototype target is planned for 2018 at an existing North Area beam line. A large part of this beam line is in common with the future BDF beam line with comparable beam characteristics and several measurement campaigns were performed in 2017 to study the optics of the line in preparation for the test. The intrinsic characteristics of the slow extraction process make the precise characterisation of the beam reaching the target particularly challenging. This paper presents beam and lattice characterisation methods and associated measurement results.

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TUPAF035

Observations of SPS Slow-Extracted Spill Quality Degradation and Possible Improvements

quadrupole, power-supply, simulation, experiment

761

F.M. Velotti, H. Bartosik, K. Cornelis, M.A. Fraser, B. Goddard, S. Hirlaender, V. Kain, O. Michels, M. Pari
CERN, Geneva, Switzerland

The SPS delivers slow extracted proton and heavy ion spills of several seconds to the North Area fixed target experiments with a very high duty factor. Reduced machine reproducibility due to magnetic history and power supply ripples on the main circuits lead however to frequent degradation of the spill duty factor. In this paper, the measured effect of the SPS magnetic history on spill quality and principal machine parameters is presented. Another detailed measurement campaign was aimed at characterising the frequency content and response of the spill to noise on the main power supplies ripples. The main findings of this study will also be reported. Finally, simulations of possible improvements based on the data acquired are discussed, as well as an extrapolation to the possible spill quality after the implementation of the improvements.

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TUPAF050

Beam Dynamics Simulations of the Effect of Power Converter Ripple on Slow Extraction at the CERN SPS

quadrupole, emittance, sextupole, experiment

818

J. Prieto, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland

The SPS provides slowly extracted protons at 400 GeV/c to CERN's North Area Fixed Target experiments over spills of duration from 1-10 seconds. Low frequency ripple on the current in the main magnets originating from their power converters is a common issue that degrades the slow-extracted spill quality. In order to better understand how the stability of the power converters affects losses, beam emittance and spill quality, particle tracking simulations were carried out using MAD-X and compared to measurements, with the impact of each magnet circuit investigated systematically. The implications for the performance of the SPS slow extraction are discussed.

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TUPAF051

Investigating Beam Loss Reduction with Octupoles During Slow Extraction in the CERN SPS

octupole, multipole, optics, simulation

822

L.S. Stoel, M. Benedikt, M.A. Fraser, B. Goddard
CERN, Geneva, Switzerland
K.A. Brown
BNL, Upton, Long Island, New York, USA

Several different methods for reducing beam loss during resonant slow extraction at the CERN Super Proton Synchrotron (SPS) are being studied. One of these methods is the use of multipoles to manipulate the separatrices in order to reduce the fraction of protons hitting the thin wires of the electrostatic extraction septum (ES). In this paper the potential of using octupoles for this purpose is explored. Beam dynamics simulations using both a simplified model and full 6D tracking in MAD-X are presented. The performance reach of such a concept at the SPS is evaluated and the potential of future machine development studies using the octupoles already installed is discussed.

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TUPAF052

Effects of Electrostatic Septum Alignment on Particle Loss During Slow Extraction at CERN SPS

alignment, simulation, operation, septum

826

J. Prieto, Y. Dutheil, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland
M.A. Kagan
SLAC, Menlo Park, California, USA

Slow extraction is an intrinsically lossy process that splits the beam with an electrostatic septum (ES), employing a thin-wire array to delimit the high electric field region that deflects the beam into the extraction channel. At CERN's Super Proton Synchrotron (SPS) the ES is over 16 m long and composed of 5 separate units containing separate wire-arrays that can be moved independently. The tanks are all mounted on a single support structure that can move the ensemble coherently. As a result, the large number of positional degrees of freedom complicates the alignment procedure in operation. Obtaining and maintaining accurate alignment of the ES with the beam is therefore crucial for minimising beam loss. In this paper, we investigate the alignment procedure for different operational scenarios using particle tracking simulations to understand the beam loss along the extraction straight as a function of the relative positions of each of the 5 separate ES units. An important aspect of the study was to understand the required alignment tolerance to achieve optimum extraction efficiency for a given configuration of wire-array thicknesses.

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TUPAF053

Optimization of Diffuser (Pre-Scatterer) Configurations for Slow Extraction Loss Reduction at Electrostatic Septa

septum, scattering, simulation, proton

830

B. Goddard, B. Balhan, J.C.C.M. Borburgh, M.A. Fraser, L.O. Jorat, V. Kain, C. Lolliot, L.S. Stoel, P. Van Trappen, F.M. Velotti
CERN, Geneva, Switzerland
D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
V.P. Nagaslaev
Fermilab, Batavia, Illinois, USA

Uncontrolled beam loss at the electrostatic septum is a performance limit for several existing or planned high power hadron accelerators delivering slow-extracted spills to fixed targets. A passive diffuser, or pre-scatterer, in a suitable configuration has been shown to reduce such beamloss significantly, with the actual gain factor depending on the parameters and details of the extraction process and hardware. In this paper, the optimization of diffuser configurations is investigated for a range of beam energies and extraction conditions, and the sensitivity to the available parameters explored via simulation results. The advantages and limitations of the diffuser are discussed and conclusions drawn concerning the specific case studies of the 8 GeV Fermilab debuncher ring and 400 GeV CERN SPS.

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TUPAF054

Slow Extraction Efficiency Measurements at the CERN SPS

proton, operation, septum, simulation

834

M.A. Fraser, K. Cornelis, L.S. Esposito, B. Goddard, V. Kain, F. Roncarolo, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland

The high efficiency of most slow extraction systems makes quantifying the exact amount of beam lost in the process extremely challenging. This is compounded by the lack of time structure in the extracted beam, as is typically required by the high-energy physics experiments, and the difficulty in accurately calibrating D.C. intensity monitors in the extraction line at count rates of ~ 10¹³ Hz. As a result, it is common for the extraction inefficiency to be measured by calibrating the beam loss signal induced by the slow extraction process itself. In this paper, measurements of the extraction efficiency performed at the CERN Super Proton Synchrotron for the third-integer resonant slow extraction of 400 GeV protons over recent years will be presented and compared to expectation from simulation. The technique employed will be discussed along with its limitations and an outlook towards a future online extraction efficiency monitoring system will be given.

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TUPAF055

Progress Toward a Dynamic Extraction Bump for Slow Extraction in the CERN SPS

simulation, alignment, septum, closed-orbit

838

L.S. Stoel, M. Benedikt, M.A. Fraser, B. Goddard, J. Prieto, F.M. Velotti
CERN, Geneva, Switzerland

The possibility of reducing the angular spread of slow extracted particles with a time-dependent extraction bump at the CERN Super Proton Synchrotron (SPS) is under investigation. In order to create this so-called dynamic bump, two orthogonal knobs were designed to enable independent movements of the beam in position and angle at the upstream end of the electrostatic extraction septum (ES). With the present slow extraction scheme, simulations show that the use of a dynamic bump can reduce the angular spread at the ES by roughly a factor two and reduce beam loss on the ES. A reduction in the angular spread is also a prerequisite to exploit the full potential of other loss reduction techniques being considered for implementation at the SPS, like the active or passive diffusers planned for installation upstream of the ES in 2018. In this paper, the simulated loss reduction with a dynamic bump alone or in combination with other loss reduction techniques will be assessed, the first beam-based tests of the dynamic bump presented, the details of its implementation examined and its potential for future operation at the SPS discussed.

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TUPAF058

Optimization of the FCC-hh Beam Extraction System Regarding Failure Avoidance and Mitigation

kicker, hardware, collider, septum

850

E. Renner, M.J. Barnes, W. Bartmann, F. Burkart, E. Carlier, L. Ducimetière, B. Goddard, T. Kramer, A. Lechner, N. Magnin, V. Senaj, J.A. Uythoven, P. Van Trappen, C. Wiesner
CERN, Geneva, Switzerland

A core part of the Future Circular Collider (FCC) study is a high energy hadron-hadron collider with a circumference of nearly 100~km and a center of mass beam energy of 100~TeV. The energy stored in one beam at top energy is 8.3~GJ, more than 20 times that of the LHC beams. Due to the large damage potential of the FCC-hh beam, the design of the beam extraction system is dominated by machine protection considerations and the requirement of avoiding any material damage in case of an asynchronous beam dump. Erratic operation of one or more extraction kickers is a main contributor to asynchronous beam dumps. The presented study shows ways to reduce the probability and mitigate the impact of erratic kicker switching. Key proposals to achieve this include layout considerations, different hardware options and alternative reaction strategies in case of erratic extraction kicker occurrence. Based on these concepts, different solutions are evaluated and an optimized design for the FCC-hh extraction system is proposed.

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TUPAF060

Injection and Dump Systems for a 13.5 TeV Hadron Synchrotron HE-LHC

kicker, injection, septum, experiment

858

W. Bartmann, M.J. Barnes, L. Ducimetière, B. Goddard, M. Hofer, T. Kramer, A. Lechner, E. Renner, A. Sanz Ull, V. Senaj, L.S. Stoel, C. Wiesner
CERN, Geneva, Switzerland

One option for a future circular collider at CERN is to build a 13.5 TeV hadron synchrotron, or High Energy LHC (HE-LHC) in the LHC tunnel. Injection and dump systems will have to be upgraded to cope with the higher beam rigidity and increased damage potential of the beam. The required modifications of the beam transfer hardware are highlighted in view of technology advancements in the field of kicker switch technology. An optimised straight section optics is shown.

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TUPAF061

Use of a Massless Septum to Increase Slow-Extraction Efficiency

septum, sextupole, simulation, resonance

862

K. Brunner, M.A. Fraser, B. Goddard, L.S. Stoel, C. Wiesner
CERN, Geneva, Switzerland
D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary

The Super Proton Synchrotron (SPS) at CERN provides slow-extracted beam for Fixed Target experiments in the North Area. For the higher extracted beam intensities requested by future experimental proposals, beam-loss induced activation will be one of the limiting factors for the availability of such a facility. In this paper, we present and discuss the concept of using a massless septum magnet to increase the extraction efficiency and decrease losses caused by protons scattering on the electrostatic-septa wires.

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TUPAF081

Measurements and Simulations of the Spill Quality of Slowly Extracted Beams from the SIS-18 Synchrotron

sextupole, synchrotron, resonance, experiment

924

S. Sorge, P. Forck, R. Singh
GSI, Darmstadt, Germany

In this contribution, results of recent measurements of the spill structure of slowly extracted beams out of the GSI heavy ion synchrotron SIS-18 are presented and compared to results of simulations. Aim of the study is the determination of spill structures at several kHz which arise from ripples in the fields of the accelerator magnets due to imperfections of the magnets' power supplies. The goal of the study is to understand how the ripple is transferred from the magnets to the spill and to find possible ways for spill smoothing. For this purpose a comprehensive simulation model for slow extraction is in preparation which will be validated with beam-based measurements.

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TUPAL018

Pulse-by-Pulse Switching of Operational Parameters in J-PARC 3-GeV RCS

emittance, operation, injection, betatron

1041

H. Hotchi, H. Harada, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, Y. Watanabe, M. Yoshimoto
JAEA/J-PARC, Tokai-mura, Japan

J-PARC 3-GeV RCS (rapid cycling synchrotron) provides a high-power beam both to MLF (materials and life science experimental facility) and MR (main ring synchrotron) by switching the beam destination pulse by pulse. The beam properties required from MLF and MR are different; MLF needs a wide-emittance beam with less charge density, while MR requires a low-emittance beam with less beam halo. To meet the antithetic requirements while keeping beam loss at permissible levels, RCS has recently initiated pulse-by-pulse switching of operational parameters (betatron tune, chromaticity, painting emittance, etc.). This paper presents the recent efforts toward the performance upgrade of RCS while discussing the related beam dynamics issues.

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TUPAL027

Design of Multi-MW Rapid Cycling Synchrotron for Accelerator Driven Transmutation System

lattice, acceleration, proton, synchrotron

1057

Y. Fuwa
Kyoto ICR, Uji, Kyoto, Japan
N. Amemiya
Kyoto University, Kyoto, Japan
Y. Ishi, Y. Kuriyama, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan

For the practical application of Accelerator Driven System (ADS) that reduces the harmfulness of radioactive waste by transmutation, we are studying the development of a compact accelerator using a synchrotron as an accelerator capable of supplying a stable proton beam to a nuclear reactor. In this plan, we aim to realize down-sizing and high reliability by adopting an alternating high temperature superconducting magnet and a high repetition synchrotron applying resonant beam extraction. In this presentation we report the basic design of the optical system and beam acceleration sequence of this synchrotron.

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TUPAL036

Slow Extraction Techniques at the Marburg Ion-Beam Therapy Centre

synchrotron, simulation, controls, resonance

1084

C. Krantz, T. Fischer, Th. Haberer, B. Kroeck, U. Scheeler, A. Weber, M. Witt
MIT, Marburg, Germany
R. Cee, F. Faber, E. Feldmeier, M. Galonska, Th. Haberer, A. Peters, S. Scheloske, C. Schömers
HIT, Heidelberg, Germany
F. Faber
Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany

The Marburg Ion-Beam Therapy Centre offers hadron therapy using proton and carbon beams. The accelerator is based on a 65-m ion synchrotron by Danfysik/Siemens Healthcare. Beam extraction from the synchrotron is driven by a transverse RF knock-out (KO) system featuring Dynamic Intensity Control (DIC) of the spill. DIC allows modulation of the extraction rate by factors up to 30 on millisecond time scales. A fast response of the system to the variable intensity set-point can be obtained by careful adjustment of the RF-KO spectrum relative to the machine tune. Tracking simulations of the extraction phase have been conducted to refine that behaviour. Presently, we investigate how fast machine tune shifts, induced by an air-core quadrupole lens, can be used as a way to further improve the spill quality.

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TUPAL059

Commissioning of Shanghai Advance Proton Therapy

proton, MMI, dipole, injection

1151

M.Z. Zhang, D.M. Li, K. Wang, Q.L. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
X.C. Xie
Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People's Republic of China

Shanghai advance proton therapy (SAPT) is a dedicate facility for cancer treatment. The commissioning of the accelerator started at the end of April 2017, and the proton beam has been already transported to the treatment room. This paper shows the commissioning results of synchrotron and transport line.

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TUPAL062

Recent Developments for Cyclotron Extraction Foils at TRIUMF

electron, cyclotron, simulation, TRIUMF

1159

Y. Bylinskii, R.A. Baartman, P.E. Dirksen, Y.-N. Rao, V.A. Verzilov
TRIUMF, Vancouver, Canada

Funding: Funded under a contribution agreement with NRC (National Research Council Canada).
The TRIUMF 500 MeV H− cyclotron employs stripping foils to extract multiple beams for different experimental programs. The upgrades in foil material and foil holders lead to significant improvements in beam quality and foil life time, as well as reduction of Be-7 contamination originated in the foils. Thus, an accumulated beam charge extracted with a single foil increased from ~60 mA·hours to more than 500 mA·hours. A key role that lead to these advances was an understanding of the foil heating mechanism, major contribution to which is paid by the power deposition from electrons stripped by the foil. To further diminish this effect, we recently introduced a foil tilt from the vertical orientation that allows stripped electrons fast escape from the foil, well before losing their original momentum through the heat deposition. Other improvements were related to operational issues. Introduction of a "combo" foil consisting of wide portion and thin wire allowed both high and low intensity beam extraction without foils sacrifice. Deploying a wedge foil for extraction at 100 MeV helped reduction of beam intensity instabilities caused by beam vertical size and position fluctuations.

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TUZGBF3

Betatron Core Slow Extraction at CNAO

betatron, synchrotron, cavity, acceleration

1237

L. Falbo, E. Bressi, S. Foglio, C. Priano
CNAO Foundation, Milan, Italy

CNAO is the only Italian hadrontherapy facility able to treat tumors with beams of protons and carbon ions. Beam is extracted with a momentum selection scheme in which beam enters the third order resonance driven by a betatron core. When irradiating a tumor, it is thought as divided in the longitudinal plane in several slices while each slice is divided in the transverse plane in several spots called voxels. Considering the dose uniformity that can be obtained during extraction, the machine must extract an average intensity related to the voxel that requires less dose. Therefore during a treatment, for some slices, a technique is needed to lower the extracted beam intensity with respect to the nominal one. A way to guarantee the correct average intensity according to the treatment planning requirements, is to introduce a mechanical filter (a degrader) that reduces the intensity of the accelerated particles. However this method used in the first treatments at CNAO showed some disadvantages and it has been replaced by what has been called the "dynamic betatron" method. The paper shows the implementations and the advantages of this method in the CNAO treatments.

Slides TUZGBF3 [2.146 MB]

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TUPMF003

Dynamic Tuning of the APS-U Booster 5-cell Cavities

booster, cavity, resonance, coupling

1251

G.J. Waldschmidt, M. Abliz, T.G. Berenc, D. Horan, U. Wienands
ANL, Argonne, Illinois, USA

The booster synchrotron for the APS-U is being upgraded to accommodate high-charge bunches, up to 20 nC, for extraction into the MBA lattice. The booster is required to operate at 85% efficiency in order to achieve bunch swap-out into the storage ring. In order to compensate for significant beam-loading effects as well as support a frequency ramp to achieve higher efficiency, a ferrite tuner is being considered to dynamically adjust the cavity frequency. A tuner design will be presented that spans 60 kHz and utilizes a low-loss YIG garnet similar to that used in the Recycler Ring at Fermilab.

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TUPMF039

Recommissioning of the Canadian Light Source Booster Synchrotron

booster, MMI, optics, injection

1338

W.A. Wurtz, D. Bertwistle, L.O. Dallin, X. Shen, J.M. Vogt
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source booster synchrotron was originally commissioned in 2002 and has worked reliably for many years. However, the operating point was not the design operating point and the booster suffered from poor quantum lifetime at the extraction energy. The low quantum lifetime caused current loss of approximately 25% in the microseconds before extraction. We have recommissioned the booster using the design optics, and the current loss before extraction is now only 6%. In this paper, we discuss the measurements and simulations involved in our recommissioning work.

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TUPMF046

The Injection and Extraction Design of the Booster for the HEPS Project

injection, kicker, storage-ring, booster

1356

Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu
IHEP, Beijing, People's Republic of China

The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.

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TUPMF062

Status of HEPS Booster Lattice Design and Physics Studies

booster, injection, lattice, storage-ring

1407

Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, C. Meng, S.K. Tian, H.S. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) with an ul-tralow emittance is proposed to be built in Beijing, Chi-na. It will utilize a booster as its full energy injector. On-axis swap-out injection is chosen as the baseline injec-tion scheme for the storage ring. As required by the stor-age ring, a beam with a bunch charge up to 2.5 nC is needed to be injected in the booster. However, limited by the transverse mode coupling instability (TMCI), such a high bunch charge is challenging. To overcome this problem, a lattice with a considerable large momentum compaction factor is designed. This paper reports the lattice design and physics studies of the HEPS booster, including injection and extraction design, error studies, eddy current effects, collective effects, and so on.

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TUPML030

Optimisation of D- Ion Production in a Multicusp Ion Source

plasma, ion-source, electron, dipole

1609

A.M. George, M.P. Dehnel, S.V. Melanson, D.E. Potkins
D-Pace, Nelson, British Columbia, Canada
N. Broderick
University of Auckland, Auckland, New Zealand
H.C. McDonald, C. Philpott
BSL, Auckland, New Zealand

D-Pace's multicusp ion source achieves high beam cur-rents for negative hydrogen ions in both the TRIUMF-licensed filament-powered ion source (~18 mA) and the University of Jyväskylä-licensed RF-powered ion source (~8 mA) [1]. It is well known that ion sources producing negative deuterium ions achieve lower beam currents compared to similar negative hydrogen ion sources and indeed we have found that negative deuterium ion beam currents in our sources are typically 1/3 that of negative hydrogen beam currents. The reasons behind this are not completely understood, but factors such as the magnetic field strength and the electron temperature are believed to play a major role and offer the potential for significant optimisation. In this paper, we look into the issues surrounding swapping of deuterium for hydrogen in our ion source by studying the properties of plasmas and extracted currents with different magnetic field strengths and gas flows.

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TUPML055

Beam Optics Designs of a Strecher Ring and a Transfer Line for J-PARC Slow Extraction

quadrupole, optics, sextupole, injection

1667

M. Tomizawa, R. Muto, T. Ogitsu
KEK, Ibaraki, Japan
A. Konaka
TRIUMF, Vancouver, Canada

The J-PARC main ring (MR) provides 30 GeV high intensity beams for neutrino experimental facility (NU) by fast extraction and hadron experimental facility (HD) by slow extraction. It is a serious issue to ensure sufficient integrated proton number on target (POT) for each facility. A stretcher ring (ST) can solve this serious problem. A beam accelerated by the MR is transferred to the ST and is slowly extracted over several second. While the beam is slowly extracted in the ST, the MR can accelerate and deliver a beam to the NU. The ST is put above the MR and fitted in the MR tunnel. Arc sections in the ST consist of superconducting combined function magnets (dipole, quadrupole and sextupole components), and separated function quadruple and sextupole magnets (hybrid lattice). A 30 GeV beam transfer line (BT) from the MR to the ST uses superconducting combined magnets with dipole and quadrupole functions to shorten the BT. The transferred beam is injected into an arc section in the ST. The adoption of the superconducting magnets in the ST and the BT saves operation cost drastically. Beam optics designs for the ST and the BT will be described in this paper.

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TUPML076

Installation, Commissioning and Characterization of EBIS-SC as a Short Pulsed Proton Source at KOMAC

electron, proton, MMI, neutron

1721

S. Lee, Y.-S. Cho, H.S. Kim, H.-J. Kwon
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea

Funding: This work has been supported through KOMAC operation fund of KAERI by MSIT (Ministry of Science and ICT)
Neutron source is applicable to various fields in basic/applied science and industries. There are several neutron sources in the world such LENS, SNS, J-PARC, ISIS and ESS either for short or long pulsed neutron. At Korea Multipurpose Accelerator Complex (KOMAC), to provide wide ranges of research opportunities to beam user, a 100 MeV proton linac based pulsed neutron source is planned for both long and short pulses of neutron source. Currently, the 100 MeV proton linac is operational with a 2 ms long pulsed proton injector, i.e. a microwave ion source. We will upgrade our injector by combining the already existing microwave ion source with a EBIS-SC (Superconducting Electron Beam Ion Source from Dreebit GmbH) for short pulses (< 1 us) of proton. This planned injector will work one at the time and provide long/short pulses of accelerated proton hitting a target to emit correspondingly long/short neutron pulses. Main modification on the proton injector is the EBIS-SC, so in this paper we report the installation, and commission of the EBIS-SC test bench at KOMAC. And the characterization of the EBIS-SC is described in detail.

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WEPAF007

A Scheme for Asynchronous Operation of the APS-U Booster Synchrotron

booster, injection, storage-ring, timing

1823

U. Wienands, T.G. Berenc, T. Fors, F. Lenkszus, N. Sereno, G.J. Waldschmidt
ANL, Argonne, Illinois, USA

Funding: Work supported by US DOE
The APS-U 6-GeV MBA storage ring will have 42 pm beam emittance and relatively tight acceptance. This requires limiting the beam emittance out of the Booster synchrotron which is achieved by operating the Booster off-momentum, thus manipulating the damping partitions. However, the much higher charge for the APS-U strongly favors injecting on momentum into the Booster for maximum acceptance. An rf-frequency ramping scheme is proposed to allow injecting on momentum and then moving the beam off momentum. The ramp is adjusted from cycle to cycle to vary the total time taken by the beam from injection to extraction, thus aligning the Booster bunch with any chosen MBA storage ring bucket. The two rf systems will not be locked at any time of the cycle. The proposed scheme is compatible with the existing synchronization of the APS injector cycle to the 60-Hz line voltage which induces a variation in the start time of the acceleration cycle. The scheme removes the need to realign the Booster ring for total path length while optimizing its operation for high charge acceleration. A ferrite tuner is being considered for dynamic tuning of the rf cavities.

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WEPAF063

RF Manipulations for Special LHC-Type Beams in the CERN PS

emittance, brightness, flattop, cavity

1971

H. Damerau, S. Hancock, A. Lasheen, D. Perrelet
CERN, Geneva, Switzerland

Beams with special longitudinal characteristics for the Large Hadron Collider (LHC) have been produced in the Proton Synchrotron (PS) and CERN. The flexibility of its RF systems consisting of in total 25 RF cavities at frequencies from 400 kHz to 200 MHz allows a variety of longitudinal beam manipulations. In particular the main RF system is split into three independent groups tunable from 2.8 MHz to 10 MHz. It is used to merge, split and change the spacing between bunches by applying different voltage and phase programs to the three groups of cavities at different harmonic numbers simultaneously. The batch compression, merging and splitting (BCMS) process has been operationally used for LHC fillings since 2016. To mitigate issues with long bunch trains in the LHC in 2017, short gaps of four bunch positions have been introduced between mini-batches of eight bunches (8b4e). A higher brightness version resulting in four mini-batches per PS extraction has been delivered for luminosity production in the LHC. This paper summarizes the operational experience and indicates possible future RF manipulation schemes.

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WEPAF083

Distributed Optical Fiber Radiation Sensing at CERN

radiation, synchrotron, distributed, operation

2039

G. Li Vecchi, M. Brugger, S. Danzeca, D. Di Francesca, R. Ferraro, Y. Kadi, O. Stein
CERN, Geneva, Switzerland
S. Girard
Univ-Lyon Laboratoire H. Curien, UMR CNRS 5516, Saint Etienne, France

The CERN's accelerator tunnels are associated with very complex mixed field radiation environments. Radiation degrades electronic components and directly affects their lifetimes causing failures that contribute to the machine downtime periods. In our contribution, we will report on the development and first employment of a Distributed Optical Fiber Radiation Sensor (DOFRS) at CERN. The most interesting feature of DOFRS technology is to provide an online and spatially distributed map of the dose levels in large machines with spatial resolution of the order of one meter. This fiber based dose sensor will provide valuable information in addition to the currently installed active and passive dosimeters. After demonstrating the working principle of DOFRS*, the first operational prototype was installed in the Proton Synchrotron Booster during last 2016/17 end-of-the-year technical stop. The DOFRS has been acquiring data successfully since the beginning of 2017 operations. The performances that were achieved by the first prototype will be discussed in the final contribution. The DOFRS measurements will also be bench-marked to the results provided by other punctual dosimeters.
*I. Toccafondo et al., 'Distributed Optical Fiber Radiation Sensing in a Mixed-Field Radiation Environment at CERN,' J. Lightw. Technol. 35, 3303, 3310, 2017.

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WEPAK007

Slow Extraction Spill Characterization From Micro to Milli-Second Scale

power-supply, resonance, experiment, betatron

2095

R. Singh, P. Boutachkov, P. Forck, S. Sorge, H. Welker
GSI, Darmstadt, Germany

This contribution deals with the topic of slow extraction spill quality characterization based on the measurements performed at GSI SIS-18. The sensitivity of the spill to power supply ripples are studied by introducing external ripples. An estimate of sources of inherent power supply ripples along with ripple magnitude are thus obtained. Spill characterization in time and frequency domain are discussed and exemplified by a typical spill and the differences from an ideal or Poisson spill. An appropriate spill characterization aims to provide a suitable abstraction for communication about the spill quality requirements between accelerator operations and users.

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WEPAL019

A Novel Field Cage Design for the CPS IPM and Systematic Errors in Beam Size and Emittance

electron, detector, cathode, emittance

2193

K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
D. Bodart, S. Levasseur, G. Schneider, J.W. Storey
CERN, Geneva, Switzerland
M. Sapinski
GSI, Darmstadt, Germany

An ionization profile monitor has been recently installed in the CERN proton synchrotron. We design a novel and simple structure field cage that suppresses the secondary electrons that are induced by the ionized ions. We discuss a field cage design, and the systematic error on the basis of beam size and emittance, considering the non-uniformity of the fields, the space-charge effect of the beam, and the lattice parameter errors.

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WEPAL025

Development of a Low-Latency, High-Precision, Beam-Based Feedback System Based on Cavity BPMs at the KEK ATF2

feedback, cavity, dipole, kicker

2212

R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, C. Perry
JAI, Oxford, United Kingdom

A low-latency, intra-train feedback system employing cavity beam position monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at KEK. The feedback system can be operated with either position information from a single BPM to provide local beam stabilisation, or by using position information from two BPMs to stabilise the beam at an intermediate location. The correction is implemented using a stripline kicker and a custom power amplifier, with the feedback calculations being performed on a digital board built around a Field Programmable Gate Array (FPGA). The addition of indium sealing to the BPMs to increase the cavities' Q-values has led to improvements to the BPM system resolution, with current measurements of the resolution of order 20 nm. The feedback performance was tested with beam trains of two bunches, separated by 280 ns and with a charge of ~1 nC. For single- (two-)BPM feedback, stabilisation of the beam has been demonstrated to below 50 nm (41 nm). Ongoing work to improve the feedback performance further will be discussed.

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WEPAL033

Development of Real-Time Mass Analysis System with Permanent Magnet for Ion Beam

ion-source, permanent-magnet, ECR, simulation

2236

Y. Takeuchi, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan

In order to analyze time variation of the ion species in a pulse, we are developing a mass analysis system that has multiple collector electrodes to detect several ion species simultaneously. Strong permanent magnets can generate 1T magnetic field and the size of the analyzing magnet system can be compact. The detected signals are scanned by a fast multiplexer. The scanning rate is 2 MHz, so that all electrode signals of the 16 channels are scanned in 8 μs period. In this paper, details of the design of the analysis system, and preliminary beam extraction test results with prototype of the system are described.

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WEPAL036

Implementation of CSNS RCS Beam Injection and Extraction Modes in Timing System

injection, timing, linac, kicker

2247

P. Zhu, M.Y. Huang, D.P. Jin, G. Lei, G.L. Xu, Y.L. Zhang
IHEP, Beijing, People's Republic of China
L. Wang
CSNS, Guangdong Province, People's Republic of China

Funding: Institute of High Energy Physics， Chinese Academy of Sciences, Beijing 100049, China; Dong guan Neutron Science Center, Dong guan 523803, China
Based on the physical design of the accelerator and the demand of the beam research, we designed four RCS beam injection modes and two RCS beam extraction modes, each of which corresponds to a series of specific timing for the accelerator. RCS beam injection and extraction modes are implemented on "VME + customized boards" hardware platform. In this paper, we will introduce the design and implementation of RCS beam injection and extraction modes as well as the RCS timing requirements and implementation in detail.

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WEPMF020

Pulsed Systems for eRHIC Beam Injection and Extraction

injection, kicker, storage-ring, electron

2410

W. Zhang, M. Blaskiewicz, A. Hershcovitch, C.J. Liaw, H. Lovelace III, M. Mapes, G.T. McIntyre, J.-L. Mi, C. Montag, C. Pai, V. Ptitsyn, J. Sandberg, N. Tsoupas, J.E. Tuozzolo, G.M. Wang, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu
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 electron-ion collider eRHIC requires a variety of kickers and septa for injection and extraction of beams throughout the entire collider complex. We plan to use pulsed systems for beam injection and extraction in Electron RCS, Electron Storage Ring, and Hadron ring. In this paper, we describe the pulsed systems required for beam transfer in the eRHIC Ring-Ring Pre-conceptual Design. We will outline the parameter ranges, technology choices, and opportunities for research and development in pulsed power technology.

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WEPMF077

Demonstration of Feasibility of the CLIC Damping Ring Extraction Kicker Modulators

kicker, flattop, damping, collider

2557

J. Holma, M.J. Barnes, A. Ferrero Colomo
CERN, Geneva, Switzerland

The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. Specifications for the electromagnetic field pulses require that the modulator produce pulses of 160 or 900 ns flattop duration, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to an ideal waveform. Inductive adder topology has been chosen for the pulse modulators where the output waveform can be adjusted by applying analogue modulation methods. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed and built, and they are being tested at CERN. These modulators will be tested with a prototype stripline kicker, installed in a beamline at ALBA Synchrotron Light Source in Spain. The results of the laboratory tests and measurements are presented.

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WEPMF087

LHC Injectors Upgrade Project: Outlook of the Modifications to the Super Proton Synchrotron (SPS) Vacuum System and Impact on the Operation of the Carbon-Coated Vacuum Chambers

vacuum, impedance, experiment, proton

2589

C. Pasquino, G. Bregliozzi, P. Chiggiato, P. Cruikshank, A. Farricker, A. Harrison, J. Perez Espinos, J.A.F. Somoza, M. Taborelli, C. Vollinger
CERN, Geneva, Switzerland

Aiming at doubling the beam intensity and reducing the beam emittance, significant modifications of the LHC and its injector chain will take place during Long Shutdown 2 (LS2), starting from 2019. The LIU project (LHC Injector Upgrade), in the specific, touches Linac4, the Proton Synchrotron Booster (PSB), the Proton Synchrotron (PS), the Super Proton Synchrotron (SPS) as well as the heavy ion chain. During LS2, important changes will take place mainly in the Long Straight Sections of the SPS to host a newly conceived dumping system, upgraded RF cavities and upgraded extraction channels. Additionally, the vacuum chambers of the main bending and focusing magnets as well as vacuum drifts will be coated with amorphous carbon in order to reduce the dynamic pressure effects induced by multipacting. The modifications to the different vacuum sectors will be described in details as well as the impact on operation of amorphous carbon coated sectors that have been already deposited.

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WEPML036

Truncated Cosine Theta Magnet and the Applications

septum, injection, collider, heavy-ion

2772

K. Sugita, E.S. Fischer, P.J. Spiller
GSI, Darmstadt, Germany

Typically septum magnets are designed with a combination of a C-shape iron yoke and a copper cable. Due to leakage of a magnetic field at a circulating beam passing through a saturated iron area, high field septum magnets with this concept is not feasible. Thus, this conventional design approach is limited magnetic field strength below 2 Tesla. For high energy machines, like SIS300 at FAIR or FCC at CERN, high field septum magnets are required to shorten the injection and extraction branch lines. Recently superconducting magnets, which enable to reduce the size of a building, are being introduced to medical accelerators. However, even if bending magnets are replaced by high field magnets, long straight sections, which is partly composed by a conventional septum magnet, remain. By introducing high field septum magnets, more compact accelerator can be designed. To get over the limitation of 2 Tesla, a novel concept of a septum magnet generating high magnetic field has been developed and design studies are ongoing. By using superconducting technology, a septum magnet can be designed to generate more than 2 Tesla. We present the concept and various application for the accelerators.

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WEPML064

Design of the Trim Coil for the Superconducting Cyclotron Extraction

cyclotron, resonance, controls, flattop

2840

L.G. Zhang, K. Fan, S. Hu, Z.Y. Mei, Z.J. Zeng
HUST, Wuhan, People's Republic of China

A proton therapy system is being developed at Huazhong university of science and technology (HUST). A 250 MeV superconducting cyclotron with an average magnetic filed of 3.1 T in the extraction region is selected to reduce the machine size, which creates difficulties for beam extraction because of the small turn separation of the beam orbits in the extraction region. To obtain high extraction efficiency, a carefully controlled magnetic perturbation is introduced to excite resonance when beam passes through the νr =1 resonance. The first-order perturbation in the magnetic field is generated by trim coils within confined regions. The profile of the trim coil and the resultant perturbation fields are optimized iteratively with orbit tracking. Simulation shows that sufficient turn separation can be obtained with the proper setting of trim coils.

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THYGBF1

High Power Beam Operation of the J-PARC RCS and MR

operation, emittance, quadrupole, betatron

2938

Y. Sato
KEK, Ibaraki, Japan

This invited talk presents the most recent status of improving J-PARC main ring (MR) beam operation together with the rapid cycling synchrotron (RCS) effort. The RCS has optimized the beam performance for the MR injection as well as the muon and neutron targets, where each requires different emittance and beam halo size. The MR has two extraction modes; fast extraction (FX) for the long baseline neutrino oscillation experiment, T2K, and slow extraction (SX) for experiments in the hadron experimental facility. At present, achieved beam intensities are 2.4·10¹⁴ protons per pulse (ppp) with cycle time 2.48 s (470 kW) in the FX mode and 5.10¹³ ppp with cycle time 5.52 s (44 kW) in the SX mode. For the FX operation, recent improvements are settings of new betatron tune, corrections of resonances near the betatron tune, and adopting 2nd harmonic rf voltage to reduce space charge effect. Beam instabilities have been suppressed with controlling chromaticity correction and transverse feedback systems. For the SX mode, a dynamic bump scheme for reducing extracted beam loss is successfully adopted. A high extraction efficiency of 99.5 % is achieved at the 44 kW beam operation.

Slides THYGBF1 [6.664 MB]

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THPAF080

SIS100 Beam Dynamics Challenges Related to the Magnet System

dipole, quadrupole, resonance, sextupole

3172

V. Kornilov, O. Boine-Frankenheim, V. Chetvertkova, S. Sorge, P.J. Spiller
GSI, Darmstadt, Germany

The SIS100 synchrotron is the central accelerator of the upcoming FAIR project at GSI, Darmstadt, Germany. The major challenges of the future operation are related to high-intensity, low beam loss operation for a wide range of ion species and charge states, for different operational cycles and extraction schemes. The magnet system consists of 108 dipole, 166 quadrupole and additional correction superconducting superferric magnets. The magnets are presently under production and testing, with detailed measurements of the magnetic field imperfections. This results in the construction of a complete database for the SIS100 magnet system. We analyse implications of the magnetic field imperfections for the single-particle stability, space charge induced tune-shifts and resonance crossing for the different SIS100 operation modi. Resonance compensation and magnet sorting schemes are discussed as possible measures.

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THPAK007

Beam Extraction from TR24 Cyclotron at IPHC

cyclotron, betatron, closed-orbit, emittance

3218

N.Yu. Kazarinov, I.A. Ivanenko
JINR, Dubna, Moscow Region, Russia
F.R. Osswald
IPHC, Strasbourg Cedex 2, France

The CYRCé cyclotron is used at IPHC (Institut Pluridisciplinaire Hubert Curien) for the production of radio-isotopes for diagnostics, medical treatments and fundamental research in radiobiology. The TR24 cyclotron manufactured and commercialized by ACSI delivers a 16-25 MeV proton beam with intensity from few nA up to 500 microA. The TR24 is a separated-sector isochronous cyclotron with normal-conducting magnet and stripper foil. It is a challenge to fit the high intensity proton beam used for target irradiation to radiobiology and analytical applications due to requirements on beam quality and energy resolution. Field distribution in the region of the extraction performed with OPERA 3D as well as beam dynamics related with stripping are analysed. 3D calculation model and hypothesis about geometry and beam are described. Our goal is to evaluate the extraction efficiency and the beam characteristics in the focusing plane outside the cyclotron which will serve as inputs for the design of future beam lines and enable beam matching conditions. Therefore, different issues are discussed: energy dispersion, transverse dynamics and orbit separation.

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THPAK019

Beam Dynamics of the First Beams for IFMIF-EVEDA RFQ Commissioning

rfq, proton, emittance, solenoid

3246

L. Bellan, C. Baltador, M. Comunian, E. Fagotti, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
T. Akagi
KEK, Ibaraki, Japan
B. Bolzon, N. Chauvin
CEA/DSM/IRFU, France
H. Dzitko
F4E, Germany
K. Kondo, M. Sugimoto
QST, Aomori, Japan
I. Podadera
CIEMAT, Madrid, Spain
F. Scantamburlo
IFMIF/EVEDA, Rokkasho, Japan

The installation of the IFMIF-EVEDA RFQ, MEBT, LEBT, source and beam dump was completed in September 2017. The beam dynamics of the first beams for the IFMIF-EVEDA RFQ commissioning is presented. Moreover, a proposal for the CW RFQ steady state commissioning is shown, with a focus on the beam dynamics challenges of the beam transport after the RFQ.

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THPAK023

Proposal for Using DAΦNE as Pulse Stretcher for the Linac Positron Beam

septum, linac, positron, pulse-stretcher

3258

S. Guiducci, D. Alesini, M.E. Biagini, S. Bilanishvili, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, D.G.C. Di Giulio, L.G. Foggetta, A. Gallo, A. Ghigo, L. Kankadze, C. Milardi, R. Ricci, U. Rotundo, L. Sabbatini, M. Serio, A. Stella
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The PADME experiment* proposes a search for the dark photon (A') in the e⁺e⁻ -> gamma A' process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Frascati National Laboratory. The linac could provide a number of positrons as high as 10⁹/pulse in a 200 ns pulse but the number of positrons for PADME is limited below 10⁵/pulse in order to keep the pile-up probability in the calorimeter low enough. The PADME experiment is indeed limited by the low duty factor (10e-5=200ns/20ms). An alternative proposal to use the DAΦNE positron ring as a linac pulse stretcher, by injecting each pulse into the ring and extracting it by a slow resonant extraction using the m/3 resonance, is described in this paper. This allows to distribute the positrons of a linac pulse in a much longer pulse (0.2 - 0.5 ms) increasing the duty factor up to ~ 2%. The required modifications of the DAΦNE positron transfer line and main ring are presented. A dedicate lattice for the ring has been designed and tracking of the positrons in the ring has been performed to optimize extraction parameters and give a preliminary estimate of the extracted beam characteristics.
* M. Raggi et al., EPJ Web Conf. 96 (2015) 01025

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THPAK028

Beam Dynamics Simulations in the Dubna SC202 Superconducting Cyclotron for Hadron Therapy

cyclotron, proton, simulation, cavity

3270

O. Karamyshev, G.A. Karamysheva, D.V. Popov, G. Shirkov, S.G. Shirkov
JINR, Dubna, Moscow Region, Russia
V. Malinin
JINR/DLNP, Dubna, Moscow region, Russia

In 2015 the joint project JINR (Dubna, Russia) - ASIPP (Hefei, China) on design and construction of supercon-ducting proton cyclotron SC202 was started. Two cyclo-trons are planned to be manufactured in China, according to the Collaboration Agreement between JINR and ASIPP. The first cyclotron will be used for proton therapy in Hefei and the second one will replace the Phasotron in the research and treatment program on proton therapy in Dubna. New schema of extraction system and results of beam acceleration and extraction simulations for Dubna cyclotron are presented.

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THPAK034

Practical Betatron Tune Behavior During Acceleration in Scaling FFAG Rings at KURNS

booster, acceleration, betatron, proton

3287

Y. Ishi, Y. Fuwa, Y. Kuriyama, Y. Mori, H. Okita, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan
J.-B. Lagrange
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

In scaling FFAG* accelerators, ideally, betatron tunes are fixed for each closed orbit concerned with the certain beam energy. Therefore, they should not vary during the acceleration. However, it is not the case since practical implementations of the magnetic field can not provide perfect scaling conditions. There are two types of radial scaling FFAG ring at Kyoto University Research Reactor Institute: one has no return yokes so called 'yoke free type' adopted by MAIN RING which has a large tune variations causing non negligible beam losses; the other has return yokes and filed clamps adopted by BOOSTER RING which has smaller tune variations compared with MAIN RING. We report the tune measurements and calculations based on 3-d magnetic field calculations about these two types of ring and discuss the scaling conditions in FFAG accelerators.
FFAG* : FFAG stands for fixed filed alternating gradient. It describes one the focusing scheme in the circular accelerator.

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THPAK105

Construction Progress of Two Superconducting Cyclotrons for Proton Therapy and Proton Irradiation at CIAE

cyclotron, proton, cavity, controls

3477

T.J. Zhang, S. An, H.R. Cai, L.C. Cao, X.L. Cao, T. Cui, X.L. Fu, T. Ge, P.F. Gong, F.P. Guan, L.L. Guan, S.G. Hou, B. Ji, X.L. Jia, M. Li, X.L. Li, Y.Q. Li, J. Lin, J.Y. Liu, X.T. Lu, Y.L. Lv, C. Wang, F. Wang, F. Wang, L. Wang, J.Y. Wei, S.M. Wei, J.S. Xing, G. Yang, J.J. Yang, M. Yin, Z.G. Yin, D.S. Zhang, S.P. Zhang, X. Zhen
CIAE, Beijing, People's Republic of China
K. Fong
TRIUMF, Vancouver, Canada

Funding: Supported partly by the National Natural Science Foundation of China (Grant No. 11375273 and 11475269) and by the Ministry of Science and Technology under Grant 2016YFC0105300.
There are very strong demand for mid-energy of proton machine recent years due to the surging cancer patients and fast progress of the space science in China. For the applications of proton therapy and proton irradiation, the energy range of proton beam usually is from 200 MeV to 250 MeV, or even higher for astronavigation. Based on the R&D starting from 2009, two construction projects of 230 MeV and 250 MeV superconducting cyclotron, which have been implemented recently at China Institute of Atomic Energy(CIAE). That was started in Jan 2015 for the 230 MeV machine, for the program of proton therapy and space science launched by China National Nuclear Corporation (CNNC), and in Jan 2016 for the 250 MeV machine, for the program of proton therapy launched by the Ministry of Science and Technology of China (MOST). In this paper, the designs for the two SC cyclotrons and their key components, including the main magnet, SC coils, RF system, internal ion source and central region, extraction system, etc, and the construction progress of the machines will be presented.

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THPAK111

Envelope Calculations on the Ion Beam Injection and Extraction of CANREB EBIS

electron, simulation, injection, TRIUMF

3496

M.H. Pereira-Wilson
UW/Physics, Waterloo, Ontario, Canada
R.A. Baartman, S. Saminathan
TRIUMF, Vancouver, Canada

An electron beam ion source (EBIS) is being developed as a charge state breeder for the production of highly charged ions in the CANREB (CANadian Rare isotope facility with Electron Beam ion source) project at TRIUMF. The multiple tunable electrodes of the EBIS, coupled with the necessity of directing both an electron beam and an ion beam of varying charge, impose a challenging task for the optimization of the beam optics. With this in mind, beam envelope simulations have been performed to determine the acceptance of the EBIS and the emittance of the extracted ion beam. The electric field of the different EBIS electrodes were modelled using finite element analysis software and the envelope simulations were executed using beam envelope code TRANSOPTR. Preliminary results show envelope calculation as a viable candidate for tuning the injection and extraction optics of the EBIS.

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THPMF013

The Stripline Kicker Prototype for the CLIC Damping Rings at ALBA: Installation, Commissioning and Beam Characterisation

kicker, storage-ring, synchrotron, impedance

4062

M. Pont, N. Ayala, M. Carlà, T.F.G. Günzel, U. Iriso, Z. Martí, R. Monge, A. Olmos, F. Pérez, M. Quispe
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
M.J. Barnes, C. Belver-Aguilar, Y. Papaphilippou
CERN, Geneva, Switzerland

The extraction system for the CLIC Damping Rings has very tight specifications. Therefore a full characterisation of the behaviour of the stripline kicker under conditions as close as possible to the expected working conditions will be very valuable. To that end the CLIC stripline has been installed in the ALBA Synchrotron Light Source and has been characterised with beam. Prior to its installation, the effect of the stripline kicker on the machine impedance has been assessed. The installation has required the design of an absorber to screen the stripline from synchrotron radiation and additional BPMs have been installed for a better kick angle determination. The commissioning of the stripline with beam has been performed following closely beam parameters, pressure and temperature. The studies with beam include the determination of the longitudinal and transverse impedance of the kicker*, the field homogeneity when excited with a dc field and the field ripple when pulsed. This contribution reports on the first experience with the stripline kicker for the CLIC DR in the ALBA storage ring and presents the results of the initial beam characterisation.
* M. Carla et al., "Beam based impedance measurements of the CLIC stripline at ALBA", Proc. of IPAC'2017.

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THPMF052

The Swap-Out Injection Scheme for the High Energy Photon Source

injection, booster, storage-ring, kicker

4178

Z. Duan, J. Chen, Y.Y. Guo, Y. Jiao, J.L. Li, Y.M. Peng, J.Q. Wang, N. Wang, G. Xu, H.S. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by Natural Science Foundation of China (No.11605212).
The on-axis swap-out scheme is a promising injection scheme for di raction-limited storage rings, since it only re- quires a rather small dynamic aperture and thus potentially allows a higher brightness compared to traditional o -axis injection schemes. However, a full charge injector is neces- sary for this scheme and its design can be nontrivial, in par- ticular to satisfy the large single bunch charge requirements in special lling patterns for timing experiments. In the High Energy Photon Source, we propose using the booster also as a high energy accumulator ring to recapture the spent bunches extracted from the storage ring, so as to relax the challenges in generation and acceleration of bunches with a high charge, and as a cost-e ective solution compared to building a dedicated full energy accumulator ring. In this paper, the beam dynamics issues of this scheme will be presented, trade-o s between the storage ring and booster beam parameters and hardware specifications will also be discussed.

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THPML080

Preliminary Results of a New High Brightness H⁻ Ion Source Developed at TRIUMF

emittance, ion-source, TRIUMF, high-voltage

4839

K. Jayamanna, F. Ames, Y. Bylinskii, J.Y. Cheng, M. Lovera, M. Minato
TRIUMF, Vancouver, Canada

This paper describes the preliminary results of a high brightness ion source developed at TRIUMF, which is capable of producing a negative hydrogen ion beam (H⁻) of up to 5 mA of direct current. A 1.7 mm.mrad and 5 mm.mrad emittance(rms) is achieved for 500 uA and for 1 mA H-, respectively. Characteristics as well as a brief description regarding extraction issues of the source to date are also presented.

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