HB2012 - List of Keywords (proton)

Paper	Title	Other Keywords	Page
MOI1B02	Technological Challenges for High-Intensity Proton Rings	linac, injection, acceleration, space-charge	15
	Y. Yamazaki FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 High-intensity, pulsed proton accelerators have been and will be requested by a wide variety of scientific fields and industrial and medical applications, for example, pulsed spallation neutron sources and neutrino sources. We will focus our discussion on the proton rings with a pulse length of a few μsec and a beam power of MW. These accelerators may be used for boosting injectors to higher-energy accelerators, like a neutrino factories. At first, we will discuss on the space-charge force which limit the stored charges in a ring together with the negative-ion injection scheme. The pulsed spallation neutron sources are classified into two schemes. One is the combination of a full-energy linac and an accumulation ring (AR) exemplified by SNS and LANSCE. The other is that of a low-energy linac and a Rapid-Cycle Synchrotron (RCS) exemplified by J-PARC RCS and ISIS. In general, pros and cons of accelerator schemes are dependent upon the technological development results. Pros and cons of AR versus RCS will be discussed on the basis of recent technological developments and beam experiment data together with the future perspectives for MW-class machines.
	Slides MOI1B02 [3.850 MB]

MOI1B03	Technical Challenges in Multi-MW Proton Linacs	linac, rfq, cryomodule, acceleration	20
	V.A. Lebedev Fermilab, Batavia, USA
	The intensity frontier research is an important part of modern elementary particle physics. It uses proton beams to create secondary beams consisting of, but not necessary limited to, neutrinos, muons, kaons and neutrons. Deferent experiments require different time structure of proton beams but all of them require the beam power of about or exceeding 1 MW. In addition, powerful proton linacs can find an application in accelerator driven nuclear reactors and transmutation of radioactive waste. Recent advances in the superconducting RF technology make a multi-MW power level economically acceptable. This paper discusses main physics and technical limitations determining ultimate parameters of such accelerators, their structure and performance.
	Slides MOI1B03 [2.863 MB]

MOI1C03	Beam Loss Mechanisms in High Intensity Linacs	linac, DTL, ion, optics	36
	M.A. Plum ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. Beam loss is a critical issue in high intensity linacs, and much work is done during both the design and operation phases to keep the loss down to manageable levels. Linacs for H⁻ ion beams have many more loss mechanisms compared to H⁺ (proton) linacs. Interesting H⁻ beam loss mechanisms include residual gas stripping, H⁺ capture and acceleration, field stripping, and intra-beam stripping (IBSt). Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H⁺ and H⁻ accelerators. The IBSt mechanism has recently been characterized at the Oak Ridge Spallation Neutron Source, and we have found that it accounts for most of the loss in the superconducting linac. In this paper we will detail the IBSt measurements, and also discuss the other beam loss mechanisms that are important for high intensity linacs.
	Slides MOI1C03 [5.588 MB]

MOP203	Bunch-by-Bunch Beam Loss Diagnostics with Diamond Detectors at the LHC	beam-losses, injection, kicker, simulation	41
	M. Hempel BTU, Cottbus, Germany T. Baer University of Hamburg, Hamburg, Germany S. Bart Pedersen, B. Dehning, E. Effinger, E. Griesmayer, A. Lechner, R. Schmidt CERN, Geneva, Switzerland W. Lohmann DESY, Hamburg, Germany
	A main challenge in the operation with high intensity beams is managing beam losses that imply the risk of quenching superconducting magnets or even damage equipment. There are various sources of beam losses, such as losses related to injection, to beam instabilities and to UFOs (Unidentified Falling Objects). Mostly surprising in the first years of LHC operation was the observation of UFOs. They are believed to be dust particles with a typical size of 1-100 um, which lead to beam losses with a duration of about ten revolutions when they fall into the beam. 3600 BLMs (Beam Loss Monitors) are installed around the LHC ring, allowing to determinate the accurate location of UFOs. The time resolution of the BLMs is 40 us (half a turn revolution). A measurement of the beam losses with a time resolution better than the bunch spacing of 50 ns is crucial to understand loss mechanisms. Diamond sensors are able to provide such diagnostics and perform particle counting with ns time resolution. In this paper, we present measurements of various types of beam losses with diamond detectors. We also compare measurements of UFO induced beam losses around the LHC ring with results from MadX simulations.

MOP209	High Intensity Proton FFAG Ring with Serpentine Acceleration for ADS	acceleration, closed-orbit, transverse-dynamics, injection	60
	E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan
	In order to produce high intensity proton beam for ADS, a new type of fixed rf acceleration scheme, so-called serpentine acceleration, is examined in scaling FFAG. Longitudinal hamiltonian for scaling FFAG is first derived analytically. Then the features of serpentine acceleration in longitudinal phase space are studied. Ring design for ADS is finally shown.

MOP213	Beam Losses due to the Foil Scattering for CSNS/RCS	beam-losses, scattering, injection, electron	78
	M.Y. Huang, N. Wang, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	For the Rapid Cycling Synchrotron of China Spallation Neutron Source (CSNS/RCS), the stripping foil scattering generates the beam halo and gives rise to additional beam losses during the injection process. The interaction between the proton beam and the stripping foil was discussed and the foil scattering was studied. A simple model and the realistic situation of the foil scattering were considered. By using the codes ORBIT and FLUKA, the multi-turn phase space painting injection process with the stripping foil scattering for CSNS/RCS was simulated and the beam losses due to the foil scattering were obtained.

MOP217	MEBT2 Design for the C-ADS Linac	emittance, linac, focusing, space-charge	93
	Z. Guo, H. Geng, Z. Li, J.Y. Tang IHEP, Beijing, People's Republic of China
	The C-ADS linac is composed by two parallel injectors and a main linac, a section of Medium Energy Beam Line (MEBT2) is designed to guide and match beams from two injectors to the main linac. The two injectors are hot-spare for each other in order to satisfied the requirement of high availability and reliability. The beam in online operation mode will be directed to the main linac from one injector, while the beam in the offline mode with low repetition frequency from the other injector, will be directed to a beam dump through an auxiliary beam line. With a long drift distance and in the presence of space charge force for 10 mA 10 MeV proton beam, the debunching effect is very strong and it requires very strict control over beam losses and emittance growth. It is difficult to obtain satisfactory longitudinal matching without bunchers in the bending section. An analytical study using transfer matrix shows that with two bunchers of same voltage in the bending section the achromatism can be maintained if the effective voltage is inversely proportional to the distance between the two bunchers. It is also under consideration if and how a beam collimation can be implanted in MEBT2.

MOP240	High Energy Tests of Advanced Materials for Beam Intercepting Devices at CERN HiRadMat Facility	simulation, vacuum, instrumentation, laser	136
	A. Bertarelli, R.W. Aßmann, E. Berthomé, V. Boccone, F. Carra, F. Cerutti, A. Dallocchio, P. Francon, L. Gentini, M. Guinchard, N. Mariani, A. Masi, P. Moyret, S. Redaelli, S.D.M. dos Santos CERN, Geneva, Switzerland L. Peroni, M. Scapin Politecnico di Torino, Torino, Italy
	Predicting by simulations the consequences of LHC particle beams hitting Collimators and other Beam Intercepting Devices (BID) is a fundamental issue for machine protection: this can be done by resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, these codes require reliable material models that, at the extreme conditions generated by a beam impact, are either imprecise or nonexistent. To validate relevant constitutive models or, when unavailable, derive new ones, a comprehensive experimental test foreseeing intense particle beam impacts on six different materials, either already used for present BID or under development for future applications, is being prepared at CERN HiRadMat facility. Tests will be run at medium and high intensity using the SPS proton beam (440 GeV). Material characterization will be carried out mostly in real time relying on embarked instrumentation (strain gauges, microphones, temperature and pressure sensors) and on remote acquisition devices (Laser Doppler Vibrometer and High-Speed Camera). Detailed post-irradiation analyses are also foreseen after the cool down of the irradiated materials.

MOP241	An Experiment on Hydrodynamic Tunnelling of the SPS High Intensity Proton Beam at the HiRadMat Facility	target, simulation, collider, linear-collider	141
	J. Blanco, F. Burkart, N. Charitonidis, I. Efthymiopoulos, D. Grenier, C. Maglioni, R. Schmidt, C. Theis, D. Wollmann CERN, Geneva, Switzerland E. Griesmayer CIVIDEC Instrumentation, Wien, Austria N.A. Tahir GSI, Darmstadt, Germany
	The LHC will collide proton beams with an energy stored in each beam of 362 MJ. To predict damage for a catastrophic failure of the protections systems, simulation studies of the impact of an LHC beam on copper targets were performed. Firstly, the energy deposition of the first bunches in a target with FLUKA is calculated. The effect of the energy deposition on the target is then calculated with a hydrodynamic code, BIG2. The impact of only a few bunches leads to a change of target density. The calculations are done iteratively in several steps and show that such beam can tunnel up to 30-35 m into a target. Similar simulations for the SPS beam also predict hydrodynamic tunnelling. An experiment at the HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS) is performed to validate the simulations. The particle energy in the SPS beam is 440 GeV and has up to 288 bunches. Significant hydrodynamic tunnelling due to hydrodynamic effects are expected. First experiments are planned for July 2012. Simulation results, the experimental setup and the outcome of the tests will be reported at this workshop.

MOP242	Experimental Verification for a Collimator with In-jaw Beam Position Monitors	alignment, simulation, collimation, closed-orbit	146
	D. Wollmann, O. Aberle, R.W. Aßmann, A. Bertarelli, C.B. Boccard, R. Bruce, F. Burkart, M. Cauchi, A. Dallocchio, D. Deboy, M. Gasior, O.R. Jones, V. Kain, L. Lari, A.A. Nosych, S. Redaelli, A. Rossi, G. Valentino CERN, Geneva, Switzerland
	At present the beam based alignment of the LHC collimators is performed by touching the beam halo with the two jaws of each device. This method requires dedicated fills at low intensities that are done infrequently because the procedure is time consuming. This limits the operational flexibility in particular in the case of changes of optics and orbit configuration in the experimental regions. The system performance relies on the machine reproducibility and regular loss maps to validate the settings. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with in-jaw beam position monitors was proposed and successfully tested with a mock-up collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper the results of these experiments are discussed. The measured alignment accuracy is compared to the accuracies achieved with the present collimators in the LHC.

MOP244	CERN High-Power Proton Synchrotron Design Study for LAGUNA-LBNO Neutrino Production	linac, synchrotron, target, status	154
	R. Steerenberg, M. Benedikt, I. Efthymiopoulos, F. Gerigk, Y. Papaphilippou CERN, Geneva, Switzerland
	Within the framework of the LAGUNA-LBNO project, CERN has started design studies in view of producing neutrinos for future long base line neutrino experiments. These design studies foresee a staged approach in the increase of the primary proton beam power, used for the neutrino production. The first step consists of exploring the feasibility of a CERN SPS beam power upgrade from the existing 500 kW, presently available to CNGS, to 750 kW. This beam should then be transferred to a new to be built neutrino beam line that is dimensioned for a beam power of 2 MW. The 2 MW proton beam is to be provided at a subsequent stage by a 30 - 50 GeV High-Power Proton Synchrotron (HP-PS), which is a major part of the design studies. This paper will provide an overview of the project and then focus on the preliminary ideas for the HP-PS design study.

MOP245	Quench Tests at the Large Hadron Collider with Collimation Losses at 3.5 Z TeV	ion, collimation, cryogenics, insertion	157
	S. Redaelli, R.W. Aßmann, G. Bellodi, K. Brodzinski, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, B. Dehning, E.B. Holzer, J.M. Jowett, E. Nebot Del Busto, M. Pojer, A. Priebe, A. Rossi, M. Sapinski, M. Schaumann, R. Schmidt, M. Solfaroli Camillocci, G. Valentino, R. Versteegen, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland L. Lari IFIC, Valencia, Spain
	The Large Hadron Collider (LHC) has been operating since 2010 at 3.5 TeV and 4.0 TeV without experiencing quenches induced by losses from circulating beams. This situation might change at 7 TeV where the reduced margins in the superconducting magnets. The critical locations are the dispersion suppressors (DSs) at either side of the cleaning and experimental insertions, where dispersive losses are maximum. It is therefore crucial to understand in detail the quench limits with beam loss distributions alike those occurring in standard operation. In order to address this aspect, quench tests were performed by inducing large beam losses on the primary collimators of the betatron cleaning insertion, for proton and lead ion beams of 3.5 Z TeV, to probe the quench limits of the DS magnets. Losses up to 500 kW were achieved without quenches. The measurement technique and the results obtained are presented, including observations of heat loads in the cryogenics system.

MOP249	Tune Spread Studies at Injection Energies for the CERN Proton Synchrotron Booster	injection, emittance, linac, space-charge	175
	B. Mikulec, A. Findlay, V. Raginel, G. Rumolo, G. Sterbini CERN, Geneva, Switzerland
	In the near future, a new H⁻ injector, Linac4, will replace the current proton injector of the CERN Proton Synchrotron Booster (PSB), Linac2. The new charge-exchange injection at 160 MeV will yield higher brightness beams compared to the conventional 50 MeV multi-turn injection of Linac2. To make full use of the higher injection energy, space-charge effects will need to be understood and mitigated to optimize the intensity versus transverse emittance reach. This includes an optimization of longitudinal acceptance and distribution with a two-harmonic rf system, careful selection of the working point to accommodate the large Laslett tune-shift of approximately -0.5 and compensation of resonances within their stopbands. This paper will present calculations of the tune spread, based on measurements of longitudinal parameters and transverse emittances, for energies up to 160 MeV, different bunch densities and varying beam intensities. It should provide valuable information on the expected tune spread after the connection of Linac4 with the PSB and input for the study of resonance compensation techniques.

MOP250	Colliding High Brightness Beams in the LHC	brightness, emittance, beam-beam-effects, luminosity	180
	T. Pieloni, X. Buffat, R. Giachino, W. Herr, E. Métral, G. Papotti CERN, Geneva, Switzerland
	The CERN-LHC is a high energy particle collider, where intense proton bunches are brought into collision. In order to achieve optimum performance, the bunches must have a high brightness, leading to strong and significant beam-beam effects. Experimental tests during the first two years of its operation have shown that beams with very high brightness can be collided head-on without detrimental effects on the beam dynamics. Such head-on collisions are therefore not expected to limit the LHC performance. Long range beam-beam interactions dominate the adverse effects on the dynamics but can profit from an increased beam brightness, in particular from small emittances. We summarize the experimental results and compare with the theoretical expectations. This allows to optimize the performance for future operation and a definition of promising upgrade scenarios.

MOP253	Progress with Bunch-shape Measurements at PSI's High-power Cyclotrons and Proton Beam Lines	cyclotron, scattering, simulation, background	187
	R. Dölling PSI, Villigen PSI, Switzerland
	As proposed at HB2010, additional bunch-shape monitors have been installed at the last turns of the Injector 2 cyclotron and at several locations in the connecting beam line to the Ring cyclotron (@72 MeV), as well as behind the Ring cyclotron (@590 MeV). Now at each location in the beam lines, longitudinal-transversal 2D-density distributions of the bunched 2.2 mA proton beam can be taken from four angles of view, each separated by 45°. In addition the monitor in Injector 2 has been upgraded to observe the 13 outermost turns (@57 to 72 MeV), some of them from two or three angles of view. The measurement setup, data evaluation and results are outlined.

MOP255	Acceleration in Vertical Orbit Excursion FFAGs with Edge Focussing	space-charge, simulation, acceleration, injection	197
	S.J. Brooks STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	FFAGs with vertical orbit excursion (VFFAGs) provide a promising alternative design for rings with fixed-field superconducting magnets. They have a vertical magnetic field component that increases with height in the vertical aperture, yielding a skew quadrupole focussing structure. Edge focussing can provide an alternating gradient within each magnet, thus reducing the ring circumference. Like spiral scaling horizontal FFAGs (but not non-scaling ones) the machine has fixed tunes and no intrinsic limitation on momentum range. Rings to accelerate the 800MeV beam from the ISIS proton synchrotron are investigated, in terms of both magnet field geometry and longitudinal behaviour during acceleration with space charge. The 12GeV ring produces an output power of at least 2.18MW.

TUO3A02	Status and Results of the UA9 Crystal Collimation Experiment at the CERN-SPS	collimation, ion, target, vacuum	245
	S. Montesano, W. Scandale CERN, Geneva, Switzerland
	The UA9 experimental setup was installed in the CERN-SPS in 2009 to investigate the feasibility of the halo collimation assisted by bent crystals. Two-millimeter-long silicon crystals, with bending angles of about 150 microrad, are used as primary collimators instead than a standard amorphous target. Studies are performed with stored beams of protons and lead ions at 270 Z GeV. The loss profile is precisely measured in the area near to the crystal-collimator setup and in the downstream dispersion suppressor. A strong correlation of the losses in the two areas is observed and a steady reduction of dispersive losses is recorded at the onset of the channeling process. The loss map in the accelerator ring is is also reduced. These observations strongly support our expectation that the coherent deflection of the beam halo by a bent crystal should enhance the collimation efficiency in hadron colliders, such as LHC. for the UA9 Collaboration
	Slides TUO3A02 [5.936 MB]

TUO1B01	Beam Loss Due to Foil Scattering in the SNS Accumulator Ring	scattering, injection, collimation, extraction	254
	J.A. Holmes, M.A. Plum ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. The Spallation Neutron Source is now operating in production mode at about 1 MW of beam power on target, which corresponds to more than 10¹⁴ protons per pulse at 60 Hz with energies exceeding 900 MeV. Although overall beam losses in production tune are low, the highest losses in the entire machine occur in the region downstream of the ring injection stripper foil. In order to better understand the contribution of scattering from the primary stripper foil to losses in the SNS ring, we have carried out calculations using the ORBIT Code aimed at evaluating these losses. These calculations indicate that the probability of beam loss within one turn following a foil hit is ~1.7·10^-8*T, where T is the foil thickness in g/cm², assuming a carbon foil. Thus, for a stripper foil of thickness T = 390 g/cm², the probability of loss within one turn of a foil hit is ~6.7·10^-6. This paper describes the calculations used to arrive at this result, presents the distribution of these losses around the SNS ring, and compares the the calculated loss distribution with that observed experimentally.
	Slides TUO1B01 [2.174 MB]

TUO1B02	Injection Design for Fermilab Project X	injection, booster, linac, dipole	259
	D.E. Johnson, C.-Y. Tan, Z. Tang Fermilab, Batavia, USA
	Fermilab is proposing a staged approach for Project X, a high power proton accelerator system. The first stage of this project will be to construct a 1 GeV CW H⁻ superconducting linear accelerator to inject into the existing 8 GeV Booster synchrotron ultimately providing in excess of 1 MW beam power for the Neutrino program out of the Main Injector. We will discuss the current project plans for injection into the Booster and related issues.
	Slides TUO1B02 [1.380 MB]

TUO3B01	Beam Dynamics Design of ESS Warm Linac	linac, rfq, DTL, emittance	274
	M. Comunian, F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy I. Bustinduy ESS Bilbao, Bilbao, Spain L. Celona, S. Gammino, L. Neri INFN/LNS, Catania, Italy R. De Prisco Lund University, Lund, Sweden M. Eshraqi, R. Miyamoto, A. Ponton ESS, Lund, Sweden
	In the present design of the European Spallation Source (ESS) accelerator, the Warm Linac will accelerate a pulsed proton beam of 50 mA peak current from source at 0.075 MeV up to 80 MeV. Such Linac is designed to operate at 352.2 MHz, with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period).In this paper the main design choices and the beam dynamics studies for the source up to the end of DTL are shown.
	Slides TUO3B01 [17.664 MB]

TUO3B02	Beam Dynamics of the ESS Superconducting Linac	linac, cavity, quadrupole, emittance	278
	M. Eshraqi, H. Danared, R. Miyamoto ESS, Lund, Sweden
	The European Spallation Source, ESS, uses a linear accelerator to deliver the high intensity proton beam to the target station. The nominal beam power is 5 MW at an energy of 2.5 GeV. The superconducting part covers more than 95\% of the energy gain and 90\% of the length. The beam dynamics criteria applied to the design of the superconducting part of the linac including the frequency jump at a medium energy of 200 MeV as well as the beam dynamics performance of this structure are described in this paper.
	Slides TUO3B02 [4.406 MB]

TUO3B05	Beam Dynamics of the 13 MeV/50 mA Proton Linac for the Compact Pulsed Hadron Source at Tsinghua University	rfq, DTL, simulation, target	289
	Q.Z. Xing, X. Guan, C. Jiang, C.-X. Tang, X.W. Wang, H.Y. Zhang, S.X. Zheng TUB, Beijing, People's Republic of China J.H. Billen, J. Stovall, L.M. Young TechSource, Santa Fe, New Mexico, USA G.H. Li NUCTECH, Beijing, People's Republic of China
	Funding: Work supported by the Major Research plan of the National Natural Science Foundation of China (Grant No. 91126003) We present the start-to-end simulation result on the high-current proton linac for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The CPHS project is a university-based proton accelerator platform (13 MeV, 16 kW, peak current 50 mA, 0.5 ms pulse width at 50 Hz) for multidisciplinary neutron and proton applications. The 13 MeV proton linac contains the ECR ion source, LEBT, RFQ, DTL and HEBT. The function of the whole accelerator system is to produce the proton beam, accelerate it to 13 MeV, and deliver it to the target where one uniform round beam spot is obtained with the diameter of 5 cm.
	Slides TUO3B05 [7.715 MB]

TUO1C01	Recent Developments on High Intensity Beam Diagnostics at SNS	electron, cathode, target, simulation	292
	W. Blokland ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. The Spallation Neutron Source Ring accumulates 0.6 μs long proton bunches of up to 1.6·10¹⁴ protons with a typical peak current of over 50 A during a 1 ms cycle. To qualify the beam, we perform different transverse profile measurements that can be done at full intensity. The electron beam scanner performs a non-invasive measurement of the transverse and longitudinal profiles of the beam in the ring. Electrons passing over and through the proton beam are deflected and projected on a fluorescent screen. Analysis of the projection yields the transverse profile while multi transverse profiles offset in time yield the longitudinal profile. Progress made with this system will be discussed as well as temperature measurements of the stripping foil and other transverse measurements.
	Slides TUO1C01 [15.498 MB]

TUO1C02	Online Monitoring System for the Waste Beam in the 3-GeV RCS of J-PARC	injection, monitoring, linac, target	297
	P.K. Saha, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	We have established two independent methods for monitoring the waste beam of only about 0.4% in the 3 GeV Rapid Cycling Synchrotron of the Japan Proton Accelerator. Although using conventional monitor systems, the measurement technique made it possible for clearly measuring such a waste beam even with significantly low error. One of the method uses a current transformer to measure the waste beam as a whole, while the other one uses a multi-wire profile monitor for clearly measuring beam profiles of both un-stripped and partially stripped components of the waste beam. While the raw signal measured by a CT (current transformer) contains a large noise, an FFT (Fast Fourier Transformation) analysis made it possible to clearly identify the beam signal corresponding to the frequency of the intermediate pulse. The waste beam was measured to be (0.38±0.03)%. Being non destructive, the 1st method is efficiently operating for online monitoring of the waste beam during the RCS user operation so as to directly know the the stripper foil condition and would have great importance for higher power operation.
	Slides TUO1C02 [2.687 MB]

TUO1C04	Detection of Unidentified Falling Objects at LHC	emittance, simulation, beam-losses, injection	305
	E. Nebot Del Busto, T. Baer, F.V. Day, B. Dehning, E.B. Holzer, A. Lechner, R. Schmidt, J. Wenninger, C. Zamantzas, M. Zerlauth, F. Zimmermann CERN, Geneva, Switzerland M. Hempel BTU, Cottbus, Germany
	About 3600 Ionization Chambers are located around the LHC ring to detect beam losses that could damage the equipment or quench superconducting magnets. The BLMs integrate the losses in 12 different time intervals (from 40 μs to 83.8 s) allowing for different abort thresholds depending on the duration of the loss and the beam energy. The signals are also recorded in a database at 1 Hz for offline analysis. Since the 2010 run, a limiting factor in the machine availability occurred due to unforeseen sudden losses appearing around the ring on the ms time scale. Those were detected exclusively by the BLM system and they are the result of the interaction of macro-particles, of sizes estimated to be 1-100 microns, with the proton beams. In this document we describe the techniques employed to identify such events as well as the mitigations implemented in the BLM system to avoid unnecessary LHC downtime.
	Slides TUO1C04 [6.812 MB]

TUO1C06	Instrumentation Developments and Beam Studies for the Fermilab Proton Improvement Plan Linac Upgrade and New RFQ Front-End	rfq, linac, ion-source, instrumentation	315
	V.E. Scarpine, D.S. Bollinger, K.L. Duel, N. Eddy, P.R. Karns, N. Liu, W. Pellico, A. Semenov, C.-Y. Tan, R.E. Tomlin Fermilab, Batavia, USA
	Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359. Fermilab is developing a Proton Improvement Plan (PIP) to increase throughput of it's the proton source. The plan addresses hardware modifications to increase repetition rate and improve beam loss while ensuring viable operation of the proton source through 2025. The first phase of the PIP will enable the Fermilab proton source to deliver 1.8·10¹⁷ protons per hour by mid-2013. As part of this initial upgrade, Fermilab plans to install a new front-end consisting of dual H⁻ ion sources and a 201 MHz pulsed RFQ. This talk will present beam studies measurements of this new front-end as well as present new beam instrumentation upgrades for the Fermilab linac.
	Slides TUO1C06 [2.546 MB]

TUO3C02	FNAL Proton Source High Intensity Operations and Beam Loss Control	booster, controls, cavity, injection	320
	F.G.G. Garcia, W. Pellico Fermilab, Batavia, USA
	Funding: U.S. Department of Energy The Proton Source (PS) has been the workhorse of the Fermi National Accelerator Laboratory (FNAL) for over 40 years. During that time the United States High Energy Physics program has continued to change with increasing demands put on the PS. The past 10 years saw an increase of over 10 fold in required hourly flux for the PS and plans are now underway to have the capability to double the output with continued operations until at least 2025. To meet these goals, effort in area of beam loss control has been a major part of the upgrades. Beam collimation and absorption systems as well as diagnostics used to mitigate and control losses have been implemented. The recent implementation of new correctors for orbit and higher harmonic control has also been very beneficial. A summary of recent and planned modification to these PS systems will be discussed.
	Slides TUO3C02 [16.766 MB]

TUO3C03	Characterizing and Controlling Beam Losses at the LANSCE Facility	linac, DTL, beam-losses, neutron	324
	L. Rybarcyk LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by DOE under contract DE-AC52-06NA25396. The Los Alamos Neutron Science Center (LANSCE) currently provides 100-MeV H⁺ and 800-MeV H⁻ beams to several user facilities that have distinct beam requirements, e.g. intensity, micropulse pattern, duty factor, etc.. Minimizing beam loss is critical to achieving good performance and reliable operation, but can be challenging in the context of simultaneous multi-beam delivery. This presentation will discuss various aspects related to the observation, characterization and minimization of beam loss associated with normal production beam operations.
	Slides TUO3C03 [3.534 MB]

WEO3A02	Beam Loss and Collimation in the ESS Linac	linac, simulation, DTL, collimation	368
	R. Miyamoto, B. Cheymol, H. Danared, M. Eshraqi, A. Ponton, J. Stovall, L. Tchelidze ESS, Lund, Sweden I. Bustinduy ESS Bilbao, Bilbao, Spain A.I.S. Holm, S.P. Møller, H.D. Thomsen ISA, Aarhus, Denmark
	The European Spallation Source (ESS), to be built in Lund, Sweden, is a spallation neutron source based on a 5 MW proton linac. A high power proton linac has a tight tolerance on beam losses to avoid activation of its components and it is ideal to study patterns of the beam loss and prepare beam loss mitigation schemes at the design stage. This paper presents simulations of the beam loss in the ESS linac as well as beam loss mitigation schemes using collimators in beam transport sections.
	Slides WEO3A02 [6.377 MB]

WEO3A03	Extraction, Transport and Collimation of the PSI 1.3 MW Proton Beam	target, extraction, cyclotron, neutron	373
	D. Reggiani PSI, Villigen PSI, Switzerland
	With an average operating beam power of 1.3 MW the PSI proton accelerator complex is currently leading the race towards the high intensity frontier of particle accelerators. This talk gives an overview of the extraction of the 590 MeV beam from the ring cyclotron and its low loss transport to the meson production targets M and E as well as to the SINQ spallation neutron source. Particular regard is given to the collimator system reshaping the beam which leaves the 40 mm thick graphite target E before reaching SINQ. Since 2011, up to 8 second long beam macro-pulses are regularly diverted to the new UCN spallation source by means of a fast kicker magnet. The switchover from the SINQ to the UCN beam line as well as the smooth beam transport up to the UCN spallation target constitute the subject of the last part of the talk.
	Slides WEO3A03 [2.728 MB]

WEO3A04	Current and Planned High Proton Flux Operations at the FNAL Booster	booster, extraction, kicker, radiation	378
	F.G.G. Garcia, W. Pellico Fermilab, Batavia, USA
	Funding: Department of Energy - Office of High Energy Physics The Fermi Lab Proton Source has seen a dramatic increase in requested flux this past decade. An increase of over ten fold in hourly flux was necessary to meet the FNAL HEP experimental requirements. This next decade will be just as challenging as the lab's HEP planning will again require the Proton Source to double the hourly flux. The recent achievements were accomplished with major upgrades such a collimation system, new correctors and aperture improvements. To achieve the next level of proton delivery rates will require even more improvements. A five year Proton Improvement Plan (PIP) is currently underway with a goal to maintain 2012 activation levels while doubling the hourly flux. Tasks in the PIP to help reduce losses include an improved beam notching system, cogging, aperture improvement and beam emittances control and reduction. This talk will describe current conditions and plans to mitigate losses with the planned increase in proton throughput.
	Slides WEO3A04 [8.309 MB]

WEO3B04	RFQ Beam Dynamics Design for Large Science Facilities and Accelerator-Driven Systems	rfq, bunching, linac, ion	419
	C. Zhang IAP, Frankfurt am Main, Germany
	Serving as the front-end of large science facilities and Accelerator-Driven Systems (ADS), the Radio-Frequency Quadrupole (RFQ) accelerator usually needs to reach low beam losses, good beam quality, high reliability, and cost savings such design goals at high beam intensities. To address the challenges for modern RFQs, a special beam dynamics design technique characterized by a reasonable and efficient bunching process with balanced space-charge forces has been developed as an alternative to the classic Four-Section Procedure proposed by Los Alamos National Laboratory (LANL). In this paper, the design studies of some recent RFQ projects will be presented as examples.
	Slides WEO3B04 [3.698 MB]

WEO1C04	Acceleration of High-Intensity Protons in the J-PARC Synchrotrons	synchrotron, cavity, extraction, injection	444
	M. Yoshii KEK/JAEA, Ibaraki-Ken, Japan
	The J-PARC consisting of the 181 MeV Linac, the 3GeV rapid cycling synchrotron (RCS) and the 50 GeV main synchrotron (MR), is the first high intensity proton synchrotron facility to use the high field gradient magnetic alloy (MA) loaded accelerating cavity. MA is a low-Q material. However, because of the high permeability and the high saturation magnetic flux density, the MA cores are the only materials to realize the required gradient. The MA loaded cavity can be considered as a stable passive load. No tuning control is necessary. 11 RF systems are installed in the RCS, and 8 RF systems in the MR. In addition, the RCS RF systems are operated in a dual harmonic mode to perform the acceleration and the longitudinal manipulation of the high intensity beam in the RCS available space. Beam loading compensation is an important issue. The feed-forward method using the RF beam signals from the wall current monitor has been established. The J-PARC synchrotrons realize stable, reproducible and clean acceleration of high intensity protons. A transition-free lattice and a precise digital timing system asynchronous to the AC-line are the distinctive features, which enable this achievement.
	Slides WEO1C04 [3.861 MB]

WEO3C02	Collimation of Ion Beams	ion, collimation, scattering, heavy-ion	461
	I. Strašík, O. Boine-Frankenheim GSI, Darmstadt, Germany
	The SIS 100 synchrotron as part of the FAIR project at GSI will accelerate various beam species from proton to uranium. An important issue is to minimize uncontrolled beam losses using a collimation system. An application of the two-stage collimation concept, well established for proton accelerators, is considered for the fully-stripped ion beams. The two-stage system consists of a primary collimator (a scattering foil) and secondary collimators (bulky absorbers). The main tasks of this study are: to specify beam optics of the system, to calculate dependence of the scattering angle in the foil on the projectile species, to investigate importance of the inelastic nuclear interaction in the foil and to calculate dependence of the collimation efficiency on the projectile species. A concept for the collimation of partially-stripped ions is based on the stripping of remaining electrons and deflecting using a beam optical element towards a dump location. Residual activation and radiation damage issues of collimator materials are also being studied at GSI. Experimental results from irradiation of carbon-based materials by heavy ions are presented.
	Slides WEO3C02 [1.485 MB]

WEO3C04	Long Baseline Neutrino Experiment Target Material Radiation Damage Studies Using Energetic Protons of the Brookhaven Linear Isotope Production (BLIP) Facility	target, lattice, neutron, radiation	471
	N. Simos BNL, Upton, Long Island, New York, USA P. Hurh Fermilab, Batavia, USA Z. Kotsina NCSR Demokritos, Attiki, Greece
	One of the future multi-MW accelerators is the LBNE Experiment where Fermilab plans to produce a beam of neutrinos with a 2.3 MW proton beam as part of a suite of experiments associated with ProjectX. Specifically, the LBNE Neutrino Beam Facility aims for a 2⁺ MW, 60-120 GeV pulsed,high intensity proton beam produced in the ProjectX accelerator intercepted by a low Z solid target to facilitate the production of low energy neutrinos. The multi-MW level LBNE proton beam will be characterized by intensities of the order of 1.6·10⁺¹⁴ p/pulse, σ_radius of 1.5-3.5 mm and a 9.8 μs pulse length. These parameters are expected to push many target materials to their limit thus making the target design very challenging. Recent experience from operating high intensity beams on targets have indicated that several critical design issues exist namely thermal shock,heat removal, radiation damage,radiation accelerated corrosion effects,and residual radiation within the target envelope. A series of experimental studies on radiation damage and thermal shock response conducted at BNL and focusing on low-Z materials have unraveled potential issues regarding the damageability from energetic particle beams which may differ significantly from thermal reactor experience. Irradiation damage results for low-Z materials associated with the LBNE and other high power experiments will be presented.
	Slides WEO3C04 [3.965 MB]

THO1A01	Beam-beam Effects in RHIC	electron, resonance, simulation, emittance	479
	Y. Luo, M. Bai, W. Fischer, C. Montag, S.M. White 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. In this article we will review the beam-beam effects in the Relativistic Heavy Ion Collider (RHIC). We will cover the experimental observations, beam-beam simulation techniques and results, and head-on beam-beam compensation with electron lenses. The next luminosity goal in the RHIC polarized proton operation is to double the luminosity with a higher proton bunch intensity. After the upgrade, the beam-beam parameter will reach 0.03. Head-on beam-beam compensation is aimed to reduce the beam-beam tune spread and non-linear beam-beam resonance driving terms.
	Slides THO1A01 [1.355 MB]

THO3B01	Proton Beam Inter-Bunch Extinction and Extinction Monitoring for the Mu2e Experiment	dipole, target, simulation, collimation	532
	E. Prebys Fermilab, Batavia, USA
	Funding: U.S. Department of Energy The goal of the Mu2e experiment at Fermilab will be the search for the conversion of a muon into an electron in the field of a nucleus, with a precision roughly four orders of magnitude better than the current limit. The experiment requires a beam consisting of short (~200 ns FW) bunches of protons are separated by roughly 1.5 microseconds. Because the most significant backgrounds are prompt with respect to the arrival of the protons, out of time beam must be suppressed at a level of at least 10^-10 relative to in time beam. The removal of out of time beam is known as "extinction". This talk will discuss the likely sources of out of time beam and the steps we plan to take to remove it. In addition, the plan for monitoring the extinction level will be presented.
	Slides THO3B01 [6.380 MB]

THO3B03	SRF Cavity Research for Project X	cavity, linac, SRF, cryomodule	541
	R.D. Kephart Fermilab, Batavia, USA
	Project X is a new SRF linac based multi-MW class proton source proposed for construction at Fermilab. It consists of a 3 MW, 1 mA CW H⁻ SRF linac that feeds an intensity frontier Physics program and a 3-8 GeV pulsed linac that accelerates ~5% of the output of the CW linac to 8 GeV for injection into the Fermilab Main Injector synchrotron resulting in an additional 2 MW of beam power at 60-120 GeV in support of a world class long baseline neutrino program. The project has chosen operating frequencies that are sub-harmonics of 1.3 GHz and is developing 6 separate cavity designs for acceleration of H⁻ particles with various velocities. An R&D program is in progress to develop these cavities; the associated cryomodules; and the required fabrication and test infrastructure. A status and progress report on this R&D program will be presented.
	Slides THO3B03 [4.034 MB]

THO1C01	High Intensity Operation and Control of Beam Losses in a Cyclotron Based Accelerator	cyclotron, target, extraction, neutron	555
	M. Seidel, J. Grillenberger, A.C. Mezger PSI, Villigen PSI, Switzerland
	This presentation discusses aspects of high intensity operation in PSI's cyclotron based proton accelerator (HIPA). Major beam loss mechanisms and tuning methods to minimize losses are presented. Concept and optimization of low loss beam extraction from a cyclotron are described. Collimators are used to localize beam losses and activation. Activation levels of accelerator components are shown. An overview on instrumentation for loss monitoring and prevention of failure situations is given. Other relevant aspects include the beam trip statistics and grid to beam power conversion efficiency.
	Slides THO1C01 [3.642 MB]

THO1C02	Beam Loss Control in the ISIS Accelerator Facility	injection, synchrotron, controls, acceleration	560
	D.J. Adams, B. Jones, A.H. Kershaw, S.J. Payne, B.G. Pine, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam lines. The facility currently delivers ~2.8·10¹³ protons per pulse at 50 Hz, splitting the pulses 40/10 between two neutron target stations. High intensity performance and operation are dominated by the need to control beam loss, which is key to sustainable machine operation and hands on maintenance. Beam loss measurement systems on ISIS are described, along with typical operational levels. The dominant beam loss in the facility occurs in the synchrotron due to high intensity effects during the H⁻ injection and longitudinal trapping processes. These losses are localised in a single superperiod using a beam collector system. Emittance growth during acceleration also drives extraction and beam transport loss at 800 MeV. Measurements, simulation and correction systems for these processes are discussed, as are the implications for further intensity upgrades.
	Slides THO1C02 [4.759 MB]

THO1C05	Status and Beam Commissioning Plan of PEFP 100 MeV Proton Linac	linac, DTL, target, site	570
	J.-H. Jang, S. Cha, Y.-S. Cho, D.I. Kim, H.S. Kim, H.-J. Kwon, Y.M. Li, B.-S. Park, J.Y. Ryu, K.T. Seol, Y.-G. Song, S.P. Yun KAERI, Daejon, Republic of Korea
	Funding: This work was supported by Ministry of Education, Science and Technology of the Korean government. The proton engineering frontier project (PEFP) is developing a 100 MeV proton linac which consists of a 50 keV injector, a 3 MeV RFQ (radio frequency quadrupole), and a 100 MeV DTL (drift tube linac). The installation of the linac was finished on March this year. The other elements including the high power RF components will be installed after completing the other part of the accelerator building. The beam commissioning is scheduled at the end of this year. This work summarized the status of the PEFP linac development and the beam commissioning plan.
	Slides THO1C05 [5.104 MB]

THO1C06	Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring	beam-losses, injection, kicker, acceleration	575
	Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii KEK, Ibaraki, Japan S. Hatakeyama, H. Hotchi, F. Tamura JAEA/J-PARC, Tokai-mura, Japan S. Nakamura, K. Satou J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.
	Slides THO1C06 [2.193 MB]

THO3C06	On-line Calibration Schemes for RF-based Beam Diagnostics	pick-up, resonance, target, diagnostics	601
	P.-A. Duperrex, U. Müller PSI, Villigen PSI, Switzerland
	RF-based beam diagnostics such as BPMs and beam current monitors rely on precise RF signal measurements. Temperature drifts and differences in the overall measurement chain gain make such measurements very challenging and calibration validity over time is an issue. Over some years, on-line calibration schemes for BPMs and current monitors have been developed. These innovative schemes are based on the use of a pilot signal at a frequency offset from the measurement frequency. Results, advantages and disadvantages of such schemes are discussed.
	Slides THO3C06 [2.742 MB]

FRO1A03	Accelerator System Design, Injection, Extraction and Beam-Material Interaction: Working Group C Summary Report	collimation, injection, ion, simulation	615
	N.V. Mokhov Fermilab, Batavia, USA D. Li LBNL, Berkeley, California, USA
	Working Group C summary:The performance of high beam power accelerators is strongly dependent on appropriate injection, acceleration and extraction system designs as well as on the way interactions of the beam with machine components are handled. The experience of the previous ICFA High-Brightness Beam workshops has proven that it is quite beneficial to combine analyses and discussion of these issues in one group, WG-C at this Workshop. A broad range of topics was presented and discussed in twenty talks at four WG-C sessions as well as at two joint WGA/C and WG-B/C sessions. Highlights from these talks, outstanding issues along with plans and proposals for future work are briefly described.
	Slides FRO1A03 [4.907 MB]

FRO1B01	Summary of the Working Group on Commissioning and Operation	beam-losses, linac, injection, simulation	620
	R. Schmidt CERN, Geneva, Switzerland M.A. Plum ORNL, Oak Ridge, Tennessee, USA Y. Sato J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The Working Group D summary report focussed on answering the following issues: observation of beam losses (e.g. time structure, other parameters,…), reducing beam losses with operational parameters away from the design set points, reducing beam losses (or concentrating beam losses at a few locations) using collimators, minimizing beam losses due to beam transfer from one accelerator to the following accelerator - what parameters are important? The issue of reducing beam losses with operational parameters away from the design set points is especially valuable as it is rarely discussed.
	Slides FRO1B01 [0.426 MB]

FRO1B02	Qinclosing Plenary Summary of Working Group E:Diagnostics and Instrumentation for High-Intensity Beams	diagnostics, beam-losses, linac, instrumentation	625
	R. Dölling PSI, Villigen PSI, Switzerland N. Hayashi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan V.E. Scarpine Fermilab, Batavia, USA
	Working Group E Summary: Working group E was charged with presentations and discussions on diagnostics and instrumentation of high intensity beams. We had 2 sessions, consisting of a total of 12 talks, each of 20 minutes for presentation followed by some discussion. One session was followed by a discussion session of two hours. All sessions took place in parallel with the sessions of WG-D (Commissioning, operations and performance), inevitably preventing some possibly useful overlap. In addition, seven posters, regarding beam diagnostics, were presented in the single poster session.
	Slides FRO1B02 [18.507 MB]

Paper

Title

Other Keywords

Page

MOI1B02

Technological Challenges for High-Intensity Proton Rings

linac, injection, acceleration, space-charge

15

Y. Yamazaki
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
High-intensity, pulsed proton accelerators have been and will be requested by a wide variety of scientific fields and industrial and medical applications, for example, pulsed spallation neutron sources and neutrino sources. We will focus our discussion on the proton rings with a pulse length of a few μsec and a beam power of MW. These accelerators may be used for boosting injectors to higher-energy accelerators, like a neutrino factories. At first, we will discuss on the space-charge force which limit the stored charges in a ring together with the negative-ion injection scheme. The pulsed spallation neutron sources are classified into two schemes. One is the combination of a full-energy linac and an accumulation ring (AR) exemplified by SNS and LANSCE. The other is that of a low-energy linac and a Rapid-Cycle Synchrotron (RCS) exemplified by J-PARC RCS and ISIS. In general, pros and cons of accelerator schemes are dependent upon the technological development results. Pros and cons of AR versus RCS will be discussed on the basis of recent technological developments and beam experiment data together with the future perspectives for MW-class machines.

Slides MOI1B02 [3.850 MB]

MOI1B03

Technical Challenges in Multi-MW Proton Linacs

linac, rfq, cryomodule, acceleration

20

V.A. Lebedev
Fermilab, Batavia, USA

The intensity frontier research is an important part of modern elementary particle physics. It uses proton beams to create secondary beams consisting of, but not necessary limited to, neutrinos, muons, kaons and neutrons. Deferent experiments require different time structure of proton beams but all of them require the beam power of about or exceeding 1 MW. In addition, powerful proton linacs can find an application in accelerator driven nuclear reactors and transmutation of radioactive waste. Recent advances in the superconducting RF technology make a multi-MW power level economically acceptable. This paper discusses main physics and technical limitations determining ultimate parameters of such accelerators, their structure and performance.

Slides MOI1B03 [2.863 MB]

MOI1C03

Beam Loss Mechanisms in High Intensity Linacs

linac, DTL, ion, optics

36

M.A. Plum
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
Beam loss is a critical issue in high intensity linacs, and much work is done during both the design and operation phases to keep the loss down to manageable levels. Linacs for H⁻ ion beams have many more loss mechanisms compared to H⁺ (proton) linacs. Interesting H⁻ beam loss mechanisms include residual gas stripping, H⁺ capture and acceleration, field stripping, and intra-beam stripping (IBSt). Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H⁺ and H⁻ accelerators. The IBSt mechanism has recently been characterized at the Oak Ridge Spallation Neutron Source, and we have found that it accounts for most of the loss in the superconducting linac. In this paper we will detail the IBSt measurements, and also discuss the other beam loss mechanisms that are important for high intensity linacs.

Slides MOI1C03 [5.588 MB]

MOP203

Bunch-by-Bunch Beam Loss Diagnostics with Diamond Detectors at the LHC

beam-losses, injection, kicker, simulation

41

M. Hempel
BTU, Cottbus, Germany
T. Baer
University of Hamburg, Hamburg, Germany
S. Bart Pedersen, B. Dehning, E. Effinger, E. Griesmayer, A. Lechner, R. Schmidt
CERN, Geneva, Switzerland
W. Lohmann
DESY, Hamburg, Germany

A main challenge in the operation with high intensity beams is managing beam losses that imply the risk of quenching superconducting magnets or even damage equipment. There are various sources of beam losses, such as losses related to injection, to beam instabilities and to UFOs (Unidentified Falling Objects). Mostly surprising in the first years of LHC operation was the observation of UFOs. They are believed to be dust particles with a typical size of 1-100 um, which lead to beam losses with a duration of about ten revolutions when they fall into the beam. 3600 BLMs (Beam Loss Monitors) are installed around the LHC ring, allowing to determinate the accurate location of UFOs. The time resolution of the BLMs is 40 us (half a turn revolution). A measurement of the beam losses with a time resolution better than the bunch spacing of 50 ns is crucial to understand loss mechanisms. Diamond sensors are able to provide such diagnostics and perform particle counting with ns time resolution. In this paper, we present measurements of various types of beam losses with diamond detectors. We also compare measurements of UFO induced beam losses around the LHC ring with results from MadX simulations.

MOP209

High Intensity Proton FFAG Ring with Serpentine Acceleration for ADS

acceleration, closed-orbit, transverse-dynamics, injection

60

E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan

In order to produce high intensity proton beam for ADS, a new type of fixed rf acceleration scheme, so-called serpentine acceleration, is examined in scaling FFAG. Longitudinal hamiltonian for scaling FFAG is first derived analytically. Then the features of serpentine acceleration in longitudinal phase space are studied. Ring design for ADS is finally shown.

MOP213

Beam Losses due to the Foil Scattering for CSNS/RCS

beam-losses, scattering, injection, electron

78

M.Y. Huang, N. Wang, S. Wang, S.Y. Xu
IHEP, Beijing, People's Republic of China

For the Rapid Cycling Synchrotron of China Spallation Neutron Source (CSNS/RCS), the stripping foil scattering generates the beam halo and gives rise to additional beam losses during the injection process. The interaction between the proton beam and the stripping foil was discussed and the foil scattering was studied. A simple model and the realistic situation of the foil scattering were considered. By using the codes ORBIT and FLUKA, the multi-turn phase space painting injection process with the stripping foil scattering for CSNS/RCS was simulated and the beam losses due to the foil scattering were obtained.

MOP217

MEBT2 Design for the C-ADS Linac

emittance, linac, focusing, space-charge

93

Z. Guo, H. Geng, Z. Li, J.Y. Tang
IHEP, Beijing, People's Republic of China

The C-ADS linac is composed by two parallel injectors and a main linac, a section of Medium Energy Beam Line (MEBT2) is designed to guide and match beams from two injectors to the main linac. The two injectors are hot-spare for each other in order to satisfied the requirement of high availability and reliability. The beam in online operation mode will be directed to the main linac from one injector, while the beam in the offline mode with low repetition frequency from the other injector, will be directed to a beam dump through an auxiliary beam line. With a long drift distance and in the presence of space charge force for 10 mA 10 MeV proton beam, the debunching effect is very strong and it requires very strict control over beam losses and emittance growth. It is difficult to obtain satisfactory longitudinal matching without bunchers in the bending section. An analytical study using transfer matrix shows that with two bunchers of same voltage in the bending section the achromatism can be maintained if the effective voltage is inversely proportional to the distance between the two bunchers. It is also under consideration if and how a beam collimation can be implanted in MEBT2.

MOP240

High Energy Tests of Advanced Materials for Beam Intercepting Devices at CERN HiRadMat Facility

simulation, vacuum, instrumentation, laser

136

A. Bertarelli, R.W. Aßmann, E. Berthomé, V. Boccone, F. Carra, F. Cerutti, A. Dallocchio, P. Francon, L. Gentini, M. Guinchard, N. Mariani, A. Masi, P. Moyret, S. Redaelli, S.D.M. dos Santos
CERN, Geneva, Switzerland
L. Peroni, M. Scapin
Politecnico di Torino, Torino, Italy

Predicting by simulations the consequences of LHC particle beams hitting Collimators and other Beam Intercepting Devices (BID) is a fundamental issue for machine protection: this can be done by resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, these codes require reliable material models that, at the extreme conditions generated by a beam impact, are either imprecise or nonexistent. To validate relevant constitutive models or, when unavailable, derive new ones, a comprehensive experimental test foreseeing intense particle beam impacts on six different materials, either already used for present BID or under development for future applications, is being prepared at CERN HiRadMat facility. Tests will be run at medium and high intensity using the SPS proton beam (440 GeV). Material characterization will be carried out mostly in real time relying on embarked instrumentation (strain gauges, microphones, temperature and pressure sensors) and on remote acquisition devices (Laser Doppler Vibrometer and High-Speed Camera). Detailed post-irradiation analyses are also foreseen after the cool down of the irradiated materials.

MOP241

An Experiment on Hydrodynamic Tunnelling of the SPS High Intensity Proton Beam at the HiRadMat Facility

target, simulation, collider, linear-collider

141

J. Blanco, F. Burkart, N. Charitonidis, I. Efthymiopoulos, D. Grenier, C. Maglioni, R. Schmidt, C. Theis, D. Wollmann
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria
N.A. Tahir
GSI, Darmstadt, Germany

The LHC will collide proton beams with an energy stored in each beam of 362 MJ. To predict damage for a catastrophic failure of the protections systems, simulation studies of the impact of an LHC beam on copper targets were performed. Firstly, the energy deposition of the first bunches in a target with FLUKA is calculated. The effect of the energy deposition on the target is then calculated with a hydrodynamic code, BIG2. The impact of only a few bunches leads to a change of target density. The calculations are done iteratively in several steps and show that such beam can tunnel up to 30-35 m into a target. Similar simulations for the SPS beam also predict hydrodynamic tunnelling. An experiment at the HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS) is performed to validate the simulations. The particle energy in the SPS beam is 440 GeV and has up to 288 bunches. Significant hydrodynamic tunnelling due to hydrodynamic effects are expected. First experiments are planned for July 2012. Simulation results, the experimental setup and the outcome of the tests will be reported at this workshop.

MOP242

Experimental Verification for a Collimator with In-jaw Beam Position Monitors

alignment, simulation, collimation, closed-orbit

146

D. Wollmann, O. Aberle, R.W. Aßmann, A. Bertarelli, C.B. Boccard, R. Bruce, F. Burkart, M. Cauchi, A. Dallocchio, D. Deboy, M. Gasior, O.R. Jones, V. Kain, L. Lari, A.A. Nosych, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland

At present the beam based alignment of the LHC collimators is performed by touching the beam halo with the two jaws of each device. This method requires dedicated fills at low intensities that are done infrequently because the procedure is time consuming. This limits the operational flexibility in particular in the case of changes of optics and orbit configuration in the experimental regions. The system performance relies on the machine reproducibility and regular loss maps to validate the settings. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with in-jaw beam position monitors was proposed and successfully tested with a mock-up collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper the results of these experiments are discussed. The measured alignment accuracy is compared to the accuracies achieved with the present collimators in the LHC.

MOP244

CERN High-Power Proton Synchrotron Design Study for LAGUNA-LBNO Neutrino Production

linac, synchrotron, target, status

154

R. Steerenberg, M. Benedikt, I. Efthymiopoulos, F. Gerigk, Y. Papaphilippou
CERN, Geneva, Switzerland

Within the framework of the LAGUNA-LBNO project, CERN has started design studies in view of producing neutrinos for future long base line neutrino experiments. These design studies foresee a staged approach in the increase of the primary proton beam power, used for the neutrino production. The first step consists of exploring the feasibility of a CERN SPS beam power upgrade from the existing 500 kW, presently available to CNGS, to 750 kW. This beam should then be transferred to a new to be built neutrino beam line that is dimensioned for a beam power of 2 MW. The 2 MW proton beam is to be provided at a subsequent stage by a 30 - 50 GeV High-Power Proton Synchrotron (HP-PS), which is a major part of the design studies. This paper will provide an overview of the project and then focus on the preliminary ideas for the HP-PS design study.

MOP245

Quench Tests at the Large Hadron Collider with Collimation Losses at 3.5 Z TeV

ion, collimation, cryogenics, insertion

157

S. Redaelli, R.W. Aßmann, G. Bellodi, K. Brodzinski, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, B. Dehning, E.B. Holzer, J.M. Jowett, E. Nebot Del Busto, M. Pojer, A. Priebe, A. Rossi, M. Sapinski, M. Schaumann, R. Schmidt, M. Solfaroli Camillocci, G. Valentino, R. Versteegen, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

The Large Hadron Collider (LHC) has been operating since 2010 at 3.5 TeV and 4.0 TeV without experiencing quenches induced by losses from circulating beams. This situation might change at 7 TeV where the reduced margins in the superconducting magnets. The critical locations are the dispersion suppressors (DSs) at either side of the cleaning and experimental insertions, where dispersive losses are maximum. It is therefore crucial to understand in detail the quench limits with beam loss distributions alike those occurring in standard operation. In order to address this aspect, quench tests were performed by inducing large beam losses on the primary collimators of the betatron cleaning insertion, for proton and lead ion beams of 3.5 Z TeV, to probe the quench limits of the DS magnets. Losses up to 500 kW were achieved without quenches. The measurement technique and the results obtained are presented, including observations of heat loads in the cryogenics system.

MOP249

Tune Spread Studies at Injection Energies for the CERN Proton Synchrotron Booster

injection, emittance, linac, space-charge

175

B. Mikulec, A. Findlay, V. Raginel, G. Rumolo, G. Sterbini
CERN, Geneva, Switzerland

In the near future, a new H⁻ injector, Linac4, will replace the current proton injector of the CERN Proton Synchrotron Booster (PSB), Linac2. The new charge-exchange injection at 160 MeV will yield higher brightness beams compared to the conventional 50 MeV multi-turn injection of Linac2. To make full use of the higher injection energy, space-charge effects will need to be understood and mitigated to optimize the intensity versus transverse emittance reach. This includes an optimization of longitudinal acceptance and distribution with a two-harmonic rf system, careful selection of the working point to accommodate the large Laslett tune-shift of approximately -0.5 and compensation of resonances within their stopbands. This paper will present calculations of the tune spread, based on measurements of longitudinal parameters and transverse emittances, for energies up to 160 MeV, different bunch densities and varying beam intensities. It should provide valuable information on the expected tune spread after the connection of Linac4 with the PSB and input for the study of resonance compensation techniques.

MOP250

Colliding High Brightness Beams in the LHC

brightness, emittance, beam-beam-effects, luminosity

180

T. Pieloni, X. Buffat, R. Giachino, W. Herr, E. Métral, G. Papotti
CERN, Geneva, Switzerland

The CERN-LHC is a high energy particle collider, where intense proton bunches are brought into collision. In order to achieve optimum performance, the bunches must have a high brightness, leading to strong and significant beam-beam effects. Experimental tests during the first two years of its operation have shown that beams with very high brightness can be collided head-on without detrimental effects on the beam dynamics. Such head-on collisions are therefore not expected to limit the LHC performance. Long range beam-beam interactions dominate the adverse effects on the dynamics but can profit from an increased beam brightness, in particular from small emittances. We summarize the experimental results and compare with the theoretical expectations. This allows to optimize the performance for future operation and a definition of promising upgrade scenarios.

MOP253

Progress with Bunch-shape Measurements at PSI's High-power Cyclotrons and Proton Beam Lines

cyclotron, scattering, simulation, background

187

R. Dölling
PSI, Villigen PSI, Switzerland

As proposed at HB2010, additional bunch-shape monitors have been installed at the last turns of the Injector 2 cyclotron and at several locations in the connecting beam line to the Ring cyclotron (@72 MeV), as well as behind the Ring cyclotron (@590 MeV). Now at each location in the beam lines, longitudinal-transversal 2D-density distributions of the bunched 2.2 mA proton beam can be taken from four angles of view, each separated by 45°. In addition the monitor in Injector 2 has been upgraded to observe the 13 outermost turns (@57 to 72 MeV), some of them from two or three angles of view. The measurement setup, data evaluation and results are outlined.

MOP255

Acceleration in Vertical Orbit Excursion FFAGs with Edge Focussing

space-charge, simulation, acceleration, injection

197

S.J. Brooks
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

FFAGs with vertical orbit excursion (VFFAGs) provide a promising alternative design for rings with fixed-field superconducting magnets. They have a vertical magnetic field component that increases with height in the vertical aperture, yielding a skew quadrupole focussing structure. Edge focussing can provide an alternating gradient within each magnet, thus reducing the ring circumference. Like spiral scaling horizontal FFAGs (but not non-scaling ones) the machine has fixed tunes and no intrinsic limitation on momentum range. Rings to accelerate the 800MeV beam from the ISIS proton synchrotron are investigated, in terms of both magnet field geometry and longitudinal behaviour during acceleration with space charge. The 12GeV ring produces an output power of at least 2.18MW.

TUO3A02

Status and Results of the UA9 Crystal Collimation Experiment at the CERN-SPS

collimation, ion, target, vacuum

245

S. Montesano, W. Scandale
CERN, Geneva, Switzerland

The UA9 experimental setup was installed in the CERN-SPS in 2009 to investigate the feasibility of the halo collimation assisted by bent crystals. Two-millimeter-long silicon crystals, with bending angles of about 150 microrad, are used as primary collimators instead than a standard amorphous target. Studies are performed with stored beams of protons and lead ions at 270 Z GeV. The loss profile is precisely measured in the area near to the crystal-collimator setup and in the downstream dispersion suppressor. A strong correlation of the losses in the two areas is observed and a steady reduction of dispersive losses is recorded at the onset of the channeling process. The loss map in the accelerator ring is is also reduced. These observations strongly support our expectation that the coherent deflection of the beam halo by a bent crystal should enhance the collimation efficiency in hadron colliders, such as LHC.
for the UA9 Collaboration

Slides TUO3A02 [5.936 MB]

TUO1B01

Beam Loss Due to Foil Scattering in the SNS Accumulator Ring

scattering, injection, collimation, extraction

254

J.A. Holmes, M.A. Plum
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
The Spallation Neutron Source is now operating in production mode at about 1 MW of beam power on target, which corresponds to more than 10¹⁴ protons per pulse at 60 Hz with energies exceeding 900 MeV. Although overall beam losses in production tune are low, the highest losses in the entire machine occur in the region downstream of the ring injection stripper foil. In order to better understand the contribution of scattering from the primary stripper foil to losses in the SNS ring, we have carried out calculations using the ORBIT Code aimed at evaluating these losses. These calculations indicate that the probability of beam loss within one turn following a foil hit is ~1.7·10^-8*T, where T is the foil thickness in g/cm², assuming a carbon foil. Thus, for a stripper foil of thickness T = 390 g/cm², the probability of loss within one turn of a foil hit is ~6.7·10^-6. This paper describes the calculations used to arrive at this result, presents the distribution of these losses around the SNS ring, and compares the the calculated loss distribution with that observed experimentally.

Slides TUO1B01 [2.174 MB]

TUO1B02

Injection Design for Fermilab Project X

injection, booster, linac, dipole

259

D.E. Johnson, C.-Y. Tan, Z. Tang
Fermilab, Batavia, USA

Fermilab is proposing a staged approach for Project X, a high power proton accelerator system. The first stage of this project will be to construct a 1 GeV CW H⁻ superconducting linear accelerator to inject into the existing 8 GeV Booster synchrotron ultimately providing in excess of 1 MW beam power for the Neutrino program out of the Main Injector. We will discuss the current project plans for injection into the Booster and related issues.

Slides TUO1B02 [1.380 MB]

TUO3B01

Beam Dynamics Design of ESS Warm Linac

linac, rfq, DTL, emittance

274

M. Comunian, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
I. Bustinduy
ESS Bilbao, Bilbao, Spain
L. Celona, S. Gammino, L. Neri
INFN/LNS, Catania, Italy
R. De Prisco
Lund University, Lund, Sweden
M. Eshraqi, R. Miyamoto, A. Ponton
ESS, Lund, Sweden

In the present design of the European Spallation Source (ESS) accelerator, the Warm Linac will accelerate a pulsed proton beam of 50 mA peak current from source at 0.075 MeV up to 80 MeV. Such Linac is designed to operate at 352.2 MHz, with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period).In this paper the main design choices and the beam dynamics studies for the source up to the end of DTL are shown.

Slides TUO3B01 [17.664 MB]

TUO3B02

Beam Dynamics of the ESS Superconducting Linac

linac, cavity, quadrupole, emittance

278

M. Eshraqi, H. Danared, R. Miyamoto
ESS, Lund, Sweden

The European Spallation Source, ESS, uses a linear accelerator to deliver the high intensity proton beam to the target station. The nominal beam power is 5 MW at an energy of 2.5 GeV. The superconducting part covers more than 95\% of the energy gain and 90\% of the length. The beam dynamics criteria applied to the design of the superconducting part of the linac including the frequency jump at a medium energy of 200 MeV as well as the beam dynamics performance of this structure are described in this paper.

Slides TUO3B02 [4.406 MB]

TUO3B05

Beam Dynamics of the 13 MeV/50 mA Proton Linac for the Compact Pulsed Hadron Source at Tsinghua University

rfq, DTL, simulation, target

289

Q.Z. Xing, X. Guan, C. Jiang, C.-X. Tang, X.W. Wang, H.Y. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China
J.H. Billen, J. Stovall, L.M. Young
TechSource, Santa Fe, New Mexico, USA
G.H. Li
NUCTECH, Beijing, People's Republic of China

Funding: Work supported by the Major Research plan of the National Natural Science Foundation of China (Grant No. 91126003)
We present the start-to-end simulation result on the high-current proton linac for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The CPHS project is a university-based proton accelerator platform (13 MeV, 16 kW, peak current 50 mA, 0.5 ms pulse width at 50 Hz) for multidisciplinary neutron and proton applications. The 13 MeV proton linac contains the ECR ion source, LEBT, RFQ, DTL and HEBT. The function of the whole accelerator system is to produce the proton beam, accelerate it to 13 MeV, and deliver it to the target where one uniform round beam spot is obtained with the diameter of 5 cm.

Slides TUO3B05 [7.715 MB]

TUO1C01

Recent Developments on High Intensity Beam Diagnostics at SNS

electron, cathode, target, simulation

292

W. Blokland
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
The Spallation Neutron Source Ring accumulates 0.6 μs long proton bunches of up to 1.6·10¹⁴ protons with a typical peak current of over 50 A during a 1 ms cycle. To qualify the beam, we perform different transverse profile measurements that can be done at full intensity. The electron beam scanner performs a non-invasive measurement of the transverse and longitudinal profiles of the beam in the ring. Electrons passing over and through the proton beam are deflected and projected on a fluorescent screen. Analysis of the projection yields the transverse profile while multi transverse profiles offset in time yield the longitudinal profile. Progress made with this system will be discussed as well as temperature measurements of the stripping foil and other transverse measurements.

Slides TUO1C01 [15.498 MB]

TUO1C02

Online Monitoring System for the Waste Beam in the 3-GeV RCS of J-PARC

injection, monitoring, linac, target

297

P.K. Saha, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

We have established two independent methods for monitoring the waste beam of only about 0.4% in the 3 GeV Rapid Cycling Synchrotron of the Japan Proton Accelerator. Although using conventional monitor systems, the measurement technique made it possible for clearly measuring such a waste beam even with significantly low error. One of the method uses a current transformer to measure the waste beam as a whole, while the other one uses a multi-wire profile monitor for clearly measuring beam profiles of both un-stripped and partially stripped components of the waste beam. While the raw signal measured by a CT (current transformer) contains a large noise, an FFT (Fast Fourier Transformation) analysis made it possible to clearly identify the beam signal corresponding to the frequency of the intermediate pulse. The waste beam was measured to be (0.38±0.03)%. Being non destructive, the 1st method is efficiently operating for online monitoring of the waste beam during the RCS user operation so as to directly know the the stripper foil condition and would have great importance for higher power operation.

Slides TUO1C02 [2.687 MB]

TUO1C04

Detection of Unidentified Falling Objects at LHC

emittance, simulation, beam-losses, injection

305

E. Nebot Del Busto, T. Baer, F.V. Day, B. Dehning, E.B. Holzer, A. Lechner, R. Schmidt, J. Wenninger, C. Zamantzas, M. Zerlauth, F. Zimmermann
CERN, Geneva, Switzerland
M. Hempel
BTU, Cottbus, Germany

About 3600 Ionization Chambers are located around the LHC ring to detect beam losses that could damage the equipment or quench superconducting magnets. The BLMs integrate the losses in 12 different time intervals (from 40 μs to 83.8 s) allowing for different abort thresholds depending on the duration of the loss and the beam energy. The signals are also recorded in a database at 1 Hz for offline analysis. Since the 2010 run, a limiting factor in the machine availability occurred due to unforeseen sudden losses appearing around the ring on the ms time scale. Those were detected exclusively by the BLM system and they are the result of the interaction of macro-particles, of sizes estimated to be 1-100 microns, with the proton beams. In this document we describe the techniques employed to identify such events as well as the mitigations implemented in the BLM system to avoid unnecessary LHC downtime.

Slides TUO1C04 [6.812 MB]

TUO1C06

Instrumentation Developments and Beam Studies for the Fermilab Proton Improvement Plan Linac Upgrade and New RFQ Front-End

rfq, linac, ion-source, instrumentation

315

V.E. Scarpine, D.S. Bollinger, K.L. Duel, N. Eddy, P.R. Karns, N. Liu, W. Pellico, A. Semenov, C.-Y. Tan, R.E. Tomlin
Fermilab, Batavia, USA

Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359.
Fermilab is developing a Proton Improvement Plan (PIP) to increase throughput of it's the proton source. The plan addresses hardware modifications to increase repetition rate and improve beam loss while ensuring viable operation of the proton source through 2025. The first phase of the PIP will enable the Fermilab proton source to deliver 1.8·10¹⁷ protons per hour by mid-2013. As part of this initial upgrade, Fermilab plans to install a new front-end consisting of dual H⁻ ion sources and a 201 MHz pulsed RFQ. This talk will present beam studies measurements of this new front-end as well as present new beam instrumentation upgrades for the Fermilab linac.

Slides TUO1C06 [2.546 MB]

TUO3C02

FNAL Proton Source High Intensity Operations and Beam Loss Control

booster, controls, cavity, injection

320

F.G.G. Garcia, W. Pellico
Fermilab, Batavia, USA

Funding: U.S. Department of Energy
The Proton Source (PS) has been the workhorse of the Fermi National Accelerator Laboratory (FNAL) for over 40 years. During that time the United States High Energy Physics program has continued to change with increasing demands put on the PS. The past 10 years saw an increase of over 10 fold in required hourly flux for the PS and plans are now underway to have the capability to double the output with continued operations until at least 2025. To meet these goals, effort in area of beam loss control has been a major part of the upgrades. Beam collimation and absorption systems as well as diagnostics used to mitigate and control losses have been implemented. The recent implementation of new correctors for orbit and higher harmonic control has also been very beneficial. A summary of recent and planned modification to these PS systems will be discussed.

Slides TUO3C02 [16.766 MB]

TUO3C03

Characterizing and Controlling Beam Losses at the LANSCE Facility

linac, DTL, beam-losses, neutron

324

L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by DOE under contract DE-AC52-06NA25396.
The Los Alamos Neutron Science Center (LANSCE) currently provides 100-MeV H⁺ and 800-MeV H⁻ beams to several user facilities that have distinct beam requirements, e.g. intensity, micropulse pattern, duty factor, etc.. Minimizing beam loss is critical to achieving good performance and reliable operation, but can be challenging in the context of simultaneous multi-beam delivery. This presentation will discuss various aspects related to the observation, characterization and minimization of beam loss associated with normal production beam operations.

Slides TUO3C03 [3.534 MB]

WEO3A02

Beam Loss and Collimation in the ESS Linac

linac, simulation, DTL, collimation

368

R. Miyamoto, B. Cheymol, H. Danared, M. Eshraqi, A. Ponton, J. Stovall, L. Tchelidze
ESS, Lund, Sweden
I. Bustinduy
ESS Bilbao, Bilbao, Spain
A.I.S. Holm, S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark

The European Spallation Source (ESS), to be built in Lund, Sweden, is a spallation neutron source based on a 5 MW proton linac. A high power proton linac has a tight tolerance on beam losses to avoid activation of its components and it is ideal to study patterns of the beam loss and prepare beam loss mitigation schemes at the design stage. This paper presents simulations of the beam loss in the ESS linac as well as beam loss mitigation schemes using collimators in beam transport sections.

Slides WEO3A02 [6.377 MB]

WEO3A03

Extraction, Transport and Collimation of the PSI 1.3 MW Proton Beam

target, extraction, cyclotron, neutron

373

D. Reggiani
PSI, Villigen PSI, Switzerland

With an average operating beam power of 1.3 MW the PSI proton accelerator complex is currently leading the race towards the high intensity frontier of particle accelerators. This talk gives an overview of the extraction of the 590 MeV beam from the ring cyclotron and its low loss transport to the meson production targets M and E as well as to the SINQ spallation neutron source. Particular regard is given to the collimator system reshaping the beam which leaves the 40 mm thick graphite target E before reaching SINQ. Since 2011, up to 8 second long beam macro-pulses are regularly diverted to the new UCN spallation source by means of a fast kicker magnet. The switchover from the SINQ to the UCN beam line as well as the smooth beam transport up to the UCN spallation target constitute the subject of the last part of the talk.

Slides WEO3A03 [2.728 MB]

WEO3A04

Current and Planned High Proton Flux Operations at the FNAL Booster

booster, extraction, kicker, radiation

378

F.G.G. Garcia, W. Pellico
Fermilab, Batavia, USA

Funding: Department of Energy - Office of High Energy Physics
The Fermi Lab Proton Source has seen a dramatic increase in requested flux this past decade. An increase of over ten fold in hourly flux was necessary to meet the FNAL HEP experimental requirements. This next decade will be just as challenging as the lab's HEP planning will again require the Proton Source to double the hourly flux. The recent achievements were accomplished with major upgrades such a collimation system, new correctors and aperture improvements. To achieve the next level of proton delivery rates will require even more improvements. A five year Proton Improvement Plan (PIP) is currently underway with a goal to maintain 2012 activation levels while doubling the hourly flux. Tasks in the PIP to help reduce losses include an improved beam notching system, cogging, aperture improvement and beam emittances control and reduction. This talk will describe current conditions and plans to mitigate losses with the planned increase in proton throughput.

Slides WEO3A04 [8.309 MB]

WEO3B04

RFQ Beam Dynamics Design for Large Science Facilities and Accelerator-Driven Systems

rfq, bunching, linac, ion

419

C. Zhang
IAP, Frankfurt am Main, Germany

Serving as the front-end of large science facilities and Accelerator-Driven Systems (ADS), the Radio-Frequency Quadrupole (RFQ) accelerator usually needs to reach low beam losses, good beam quality, high reliability, and cost savings such design goals at high beam intensities. To address the challenges for modern RFQs, a special beam dynamics design technique characterized by a reasonable and efficient bunching process with balanced space-charge forces has been developed as an alternative to the classic Four-Section Procedure proposed by Los Alamos National Laboratory (LANL). In this paper, the design studies of some recent RFQ projects will be presented as examples.

Slides WEO3B04 [3.698 MB]

WEO1C04

Acceleration of High-Intensity Protons in the J-PARC Synchrotrons

synchrotron, cavity, extraction, injection

444

M. Yoshii
KEK/JAEA, Ibaraki-Ken, Japan

The J-PARC consisting of the 181 MeV Linac, the 3GeV rapid cycling synchrotron (RCS) and the 50 GeV main synchrotron (MR), is the first high intensity proton synchrotron facility to use the high field gradient magnetic alloy (MA) loaded accelerating cavity. MA is a low-Q material. However, because of the high permeability and the high saturation magnetic flux density, the MA cores are the only materials to realize the required gradient. The MA loaded cavity can be considered as a stable passive load. No tuning control is necessary. 11 RF systems are installed in the RCS, and 8 RF systems in the MR. In addition, the RCS RF systems are operated in a dual harmonic mode to perform the acceleration and the longitudinal manipulation of the high intensity beam in the RCS available space. Beam loading compensation is an important issue. The feed-forward method using the RF beam signals from the wall current monitor has been established. The J-PARC synchrotrons realize stable, reproducible and clean acceleration of high intensity protons. A transition-free lattice and a precise digital timing system asynchronous to the AC-line are the distinctive features, which enable this achievement.

Slides WEO1C04 [3.861 MB]

WEO3C02

Collimation of Ion Beams

ion, collimation, scattering, heavy-ion

461

I. Strašík, O. Boine-Frankenheim
GSI, Darmstadt, Germany

The SIS 100 synchrotron as part of the FAIR project at GSI will accelerate various beam species from proton to uranium. An important issue is to minimize uncontrolled beam losses using a collimation system. An application of the two-stage collimation concept, well established for proton accelerators, is considered for the fully-stripped ion beams. The two-stage system consists of a primary collimator (a scattering foil) and secondary collimators (bulky absorbers). The main tasks of this study are:

to specify beam optics of the system,
to calculate dependence of the scattering angle in the foil on the projectile species,
to investigate importance of the inelastic nuclear interaction in the foil and
to calculate dependence of the collimation efficiency on the projectile species.

A concept for the collimation of partially-stripped ions is based on the stripping of remaining electrons and deflecting using a beam optical element towards a dump location. Residual activation and radiation damage issues of collimator materials are also being studied at GSI. Experimental results from irradiation of carbon-based materials by heavy ions are presented.

Slides WEO3C02 [1.485 MB]

WEO3C04

Long Baseline Neutrino Experiment Target Material Radiation Damage Studies Using Energetic Protons of the Brookhaven Linear Isotope Production (BLIP) Facility

target, lattice, neutron, radiation

471

N. Simos
BNL, Upton, Long Island, New York, USA
P. Hurh
Fermilab, Batavia, USA
Z. Kotsina
NCSR Demokritos, Attiki, Greece

One of the future multi-MW accelerators is the LBNE Experiment where Fermilab plans to produce a beam of neutrinos with a 2.3 MW proton beam as part of a suite of experiments associated with ProjectX. Specifically, the LBNE Neutrino Beam Facility aims for a 2⁺ MW, 60-120 GeV pulsed,high intensity proton beam produced in the ProjectX accelerator intercepted by a low Z solid target to facilitate the production of low energy neutrinos. The multi-MW level LBNE proton beam will be characterized by intensities of the order of 1.6·10⁺¹⁴ p/pulse, σ_radius of 1.5-3.5 mm and a 9.8 μs pulse length. These parameters are expected to push many target materials to their limit thus making the target design very challenging. Recent experience from operating high intensity beams on targets have indicated that several critical design issues exist namely thermal shock,heat removal, radiation damage,radiation accelerated corrosion effects,and residual radiation within the target envelope. A series of experimental studies on radiation damage and thermal shock response conducted at BNL and focusing on low-Z materials have unraveled potential issues regarding the damageability from energetic particle beams which may differ significantly from thermal reactor experience. Irradiation damage results for low-Z materials associated with the LBNE and other high power experiments will be presented.

Slides WEO3C04 [3.965 MB]

THO1A01

Beam-beam Effects in RHIC

electron, resonance, simulation, emittance

479

Y. Luo, M. Bai, W. Fischer, C. Montag, S.M. White
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.
In this article we will review the beam-beam effects in the Relativistic Heavy Ion Collider (RHIC). We will cover the experimental observations, beam-beam simulation techniques and results, and head-on beam-beam compensation with electron lenses. The next luminosity goal in the RHIC polarized proton operation is to double the luminosity with a higher proton bunch intensity. After the upgrade, the beam-beam parameter will reach 0.03. Head-on beam-beam compensation is aimed to reduce the beam-beam tune spread and non-linear beam-beam resonance driving terms.

Slides THO1A01 [1.355 MB]

THO3B01

Proton Beam Inter-Bunch Extinction and Extinction Monitoring for the Mu2e Experiment

dipole, target, simulation, collimation

532

E. Prebys
Fermilab, Batavia, USA

Funding: U.S. Department of Energy
The goal of the Mu2e experiment at Fermilab will be the search for the conversion of a muon into an electron in the field of a nucleus, with a precision roughly four orders of magnitude better than the current limit. The experiment requires a beam consisting of short (~200 ns FW) bunches of protons are separated by roughly 1.5 microseconds. Because the most significant backgrounds are prompt with respect to the arrival of the protons, out of time beam must be suppressed at a level of at least 10^-10 relative to in time beam. The removal of out of time beam is known as "extinction". This talk will discuss the likely sources of out of time beam and the steps we plan to take to remove it. In addition, the plan for monitoring the extinction level will be presented.

Slides THO3B01 [6.380 MB]

THO3B03

SRF Cavity Research for Project X

cavity, linac, SRF, cryomodule

541

R.D. Kephart
Fermilab, Batavia, USA

Project X is a new SRF linac based multi-MW class proton source proposed for construction at Fermilab. It consists of a 3 MW, 1 mA CW H⁻ SRF linac that feeds an intensity frontier Physics program and a 3-8 GeV pulsed linac that accelerates ~5% of the output of the CW linac to 8 GeV for injection into the Fermilab Main Injector synchrotron resulting in an additional 2 MW of beam power at 60-120 GeV in support of a world class long baseline neutrino program. The project has chosen operating frequencies that are sub-harmonics of 1.3 GHz and is developing 6 separate cavity designs for acceleration of H⁻ particles with various velocities. An R&D program is in progress to develop these cavities; the associated cryomodules; and the required fabrication and test infrastructure. A status and progress report on this R&D program will be presented.

Slides THO3B03 [4.034 MB]

THO1C01

High Intensity Operation and Control of Beam Losses in a Cyclotron Based Accelerator

cyclotron, target, extraction, neutron

555

M. Seidel, J. Grillenberger, A.C. Mezger
PSI, Villigen PSI, Switzerland

This presentation discusses aspects of high intensity operation in PSI's cyclotron based proton accelerator (HIPA). Major beam loss mechanisms and tuning methods to minimize losses are presented. Concept and optimization of low loss beam extraction from a cyclotron are described. Collimators are used to localize beam losses and activation. Activation levels of accelerator components are shown. An overview on instrumentation for loss monitoring and prevention of failure situations is given. Other relevant aspects include the beam trip statistics and grid to beam power conversion efficiency.

Slides THO1C01 [3.642 MB]

THO1C02

Beam Loss Control in the ISIS Accelerator Facility

injection, synchrotron, controls, acceleration

560

D.J. Adams, B. Jones, A.H. Kershaw, S.J. Payne, B.G. Pine, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam lines. The facility currently delivers ~2.8·10¹³ protons per pulse at 50 Hz, splitting the pulses 40/10 between two neutron target stations. High intensity performance and operation are dominated by the need to control beam loss, which is key to sustainable machine operation and hands on maintenance. Beam loss measurement systems on ISIS are described, along with typical operational levels. The dominant beam loss in the facility occurs in the synchrotron due to high intensity effects during the H⁻ injection and longitudinal trapping processes. These losses are localised in a single superperiod using a beam collector system. Emittance growth during acceleration also drives extraction and beam transport loss at 800 MeV. Measurements, simulation and correction systems for these processes are discussed, as are the implications for further intensity upgrades.

Slides THO1C02 [4.759 MB]

THO1C05

Status and Beam Commissioning Plan of PEFP 100 MeV Proton Linac

linac, DTL, target, site

570

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

Funding: This work was supported by Ministry of Education, Science and Technology of the Korean government.
The proton engineering frontier project (PEFP) is developing a 100 MeV proton linac which consists of a 50 keV injector, a 3 MeV RFQ (radio frequency quadrupole), and a 100 MeV DTL (drift tube linac). The installation of the linac was finished on March this year. The other elements including the high power RF components will be installed after completing the other part of the accelerator building. The beam commissioning is scheduled at the end of this year. This work summarized the status of the PEFP linac development and the beam commissioning plan.

Slides THO1C05 [5.104 MB]

THO1C06

Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring

beam-losses, injection, kicker, acceleration

575

Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii
KEK, Ibaraki, Japan
S. Hatakeyama, H. Hotchi, F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
S. Nakamura, K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.

Slides THO1C06 [2.193 MB]

THO3C06

On-line Calibration Schemes for RF-based Beam Diagnostics

pick-up, resonance, target, diagnostics

601

P.-A. Duperrex, U. Müller
PSI, Villigen PSI, Switzerland

RF-based beam diagnostics such as BPMs and beam current monitors rely on precise RF signal measurements. Temperature drifts and differences in the overall measurement chain gain make such measurements very challenging and calibration validity over time is an issue. Over some years, on-line calibration schemes for BPMs and current monitors have been developed. These innovative schemes are based on the use of a pilot signal at a frequency offset from the measurement frequency. Results, advantages and disadvantages of such schemes are discussed.

Slides THO3C06 [2.742 MB]

FRO1A03

Accelerator System Design, Injection, Extraction and Beam-Material Interaction: Working Group C Summary Report

collimation, injection, ion, simulation

615

N.V. Mokhov
Fermilab, Batavia, USA
D. Li
LBNL, Berkeley, California, USA

Working Group C summary:The performance of high beam power accelerators is strongly dependent on appropriate injection, acceleration and extraction system designs as well as on the way interactions of the beam with machine components are handled. The experience of the previous ICFA High-Brightness Beam workshops has proven that it is quite beneficial to combine analyses and discussion of these issues in one group, WG-C at this Workshop. A broad range of topics was presented and discussed in twenty talks at four WG-C sessions as well as at two joint WGA/C and WG-B/C sessions. Highlights from these talks, outstanding issues along with plans and proposals for future work are briefly described.

Slides FRO1A03 [4.907 MB]

FRO1B01

Summary of the Working Group on Commissioning and Operation

beam-losses, linac, injection, simulation

620

R. Schmidt
CERN, Geneva, Switzerland
M.A. Plum
ORNL, Oak Ridge, Tennessee, USA
Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The Working Group D summary report focussed on answering the following issues:

observation of beam losses (e.g. time structure, other parameters,…),
reducing beam losses with operational parameters away from the design set points,
reducing beam losses (or concentrating beam losses at a few locations) using collimators,
minimizing beam losses due to beam transfer from one accelerator to the following accelerator - what parameters are important?

The issue of reducing beam losses with operational parameters away from the design set points is especially valuable as it is rarely discussed.

Slides FRO1B01 [0.426 MB]

FRO1B02

Qinclosing Plenary Summary of Working Group E:Diagnostics and Instrumentation for High-Intensity Beams

diagnostics, beam-losses, linac, instrumentation

625

R. Dölling
PSI, Villigen PSI, Switzerland
N. Hayashi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
V.E. Scarpine
Fermilab, Batavia, USA

Working Group E Summary: Working group E was charged with presentations and discussions on diagnostics and instrumentation of high intensity beams. We had 2 sessions, consisting of a total of 12 talks, each of 20 minutes for presentation followed by some discussion. One session was followed by a discussion session of two hours. All sessions took place in parallel with the sessions of WG-D (Commissioning, operations and performance), inevitably preventing some possibly useful overlap. In addition, seven posters, regarding beam diagnostics, were presented in the single poster session.

Slides FRO1B02 [18.507 MB]