IPAC2012 - List of Keywords (scattering)

Paper	Title	Other Keywords	Page
MOPPC007	Plans for High Beta Optics in the LHC	optics, quadrupole, emittance, insertion	133
	H. Burkhardt, A. Macpherson CERN, Geneva, Switzerland S. Cavalier, P.M. Puzo LAL, Orsay, France
	Based on what has been learned with the first high β^* = 90 m operation in 2011, we describe the potential and practical scenarios for reaching very high β^* in the LHC in 2012 and beyond. Very high β^* optics require dedicated running time and conditions in the LHC. We describe a plan which is optimized to maximize the physics potential in a minimum of dedicated running time.

MOPPC008	LHC Optics Determination with Proton Tracks Measured in the Roman Pots Detectors of the TOTEM Experiment	proton, optics, lattice, coupling	136
	H. Niewiadomski, H. Burkhardt CERN, Geneva, Switzerland F.J. Nemes KFKI, Budapest, Hungary
	The TOTEM experiment at the LHC is equipped with near beam movable devices – called Roman Pots (RP) – which detect protons scattered at the interaction point (IP) arrived to the detectors through the magnet lattice of the LHC. Proton kinematics at IP is reconstructed from positions and angles measured by the RP detectors, on the basis of the optical functions between IP and the RP locations. The precision of optics determination is therefore of the key importance for the experiment. TOTEM developed a novel method of machine optics determination making use of angle-position distributions of elastically scattered protons observed in the RP detectors. The method has been successfully applied to the data samples registered in 2010 and 2011. The studies have shown that the transport matrix could be estimated with a precision better than 1%.

MOPPD009	Stochastic Cooling Developments for HESR at FAIR	target, ion, heavy-ion, emittance	388
	H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich, Germany C. Dimopoulou, A. Dolinskii, T. Katayama, Yu.A. Litvinov, M. Steck, T. Stöhlker GSI, Darmstadt, Germany
	The High-Energy Storage Ring (HESR) is part of the upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. The HESR is planned to dedicate to the field of high-energy antiproton physics to explore the research areas of charmonium spectroscopy, hadronic structure, and quark-gluon dynamics with high-quality beams over a broad momentum range from 1.5 to 15 GeV/c. The new facility provides the combination of powerful phase-space cooled antiproton beams and internal Pellet and gas jet targets to achieve the requirements of the experiment PANDA in terms of beam quality and luminosity. Detailed theoretical analyses have been carried out to design the stochastic cooling system for accumulation and stochastic cooling of antiprotons with target operation. Recently it is proposed to utilize the HESR also for the atomic and nuclear physics with highly charged heavy ions such as 132Sn⁵⁰⁺ in the dedicated experiments at high energies 0.74-3 GeV/u. In this contribution the feasibility of stochastic cooling of heavy ions with internal targets is in detail investigated under the constraint of the cooling system hardware as foreseen for anti-proton cooling.

MOPPD052	Study of Electrostatic Septum by Low-Z Material for High Intensity Proton Beam	septum, extraction, proton, beam-losses	484
	D. Horikawa Sokendai, Ibaraki, Japan Y. Arakaki, K. Okamura, Y. Shirakabe, M. Tomizawa KEK, Ibaraki, Japan I. Sakai University of Fukui, Faculty of Engineering, Fukui, Japan T. Shimogawa Saga University, Faculty of Science and Engineering, Saga, Japan
	In a high-intensity proton accelerator, the beam loss at the time of late beam extraction causes radioactivation of apparatus. It takes out and is a problem serious to that of upper about beam power. Its attention was paid to electric septum (ESS) of the equipment used for beam extraction for problem solving. The septum section of ESS which beam hits directly is usually used for tungsten. Therefore, it is low atomic number material to the septum section. Development of the new model ESS using the textile material carbon fiber of a certain carbon (CF) was started. Is it a problem in CF at processability? Is it using for the septum section of ESS for a certain reason? Difficult it was. Therefore, it succeeded in obtaining required form and intensity by developing the twisting thread technology of CF. Moreover, the tension strength test of CFwire and the pyrogenicity test by electric current were done. Is it the tension intensity and heat durability which exceed the existing tungsten wire? It was confirmed. In addition to the ESS development technique using these new materials, and a result, a future measure is reported.

MOPPD064	Simulation of Double Layer Carbon Stripping Foils for ISIS Injection Upgrades	injection, simulation, radiation, proton	514
	H. V. Smith, D.J. Adams, B. Jones, C.M. Warsop STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom Y. Irie, Y. Takeda KEK, Ibaraki, Japan
	ISIS, the pulsed neutron and muon spallation source located at the Rutherford Appleton Laboratory (UK), currently delivers a mean beam power of 0.2 MW to target. A 70 MeV H linear accelerator feeds into a 50 Hz, 800 MeV proton synchrotron, accelerating up to 3·10¹³ protons per pulse. Potential injection scheme upgrades, aiming to raise average beam power towards 0.5 MW with a new 180 MeV linear accelerator, continue to be studied. This paper highlights recent results from temperature studies of double layer carbon foils, suitable for injection at 180 MeV into ISIS, using ANSYS. Experimental data from KEK was used to benchmark models and the variation of temperature as a function of foil separation was considered.

MOPPD067	Novel Slow Extraction Scheme for Proton Accelerators Using Pulsed Dipole Correctors and Crystals	extraction, septum, proton, betatron	517
	V.D. Shiltsev Fermilab, Batavia, USA
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359 Slow extraction of protons beams from circular accelerators is currently widely used for a variety of beam-based experiments. The method has some deficiencies including limited efficiency of extraction, radiation induced due to scattering on the electrostatic septa and limited beam pipe aperture, beam dynamics effects of space charge forces and magnet power supplies ripple. Here we present a novel slow extraction scheme employing a number of non-standard accelerator elements, such as Silicone crystal strips and pulsed strip-line dipole correctors, and illustrate practicality of these examples at the 8 GeV proton Recycler Ring at Fermilab.

MOPPD074	Localization of Large Angle Foil Scattering Beam Loss Caused by Multi-Turn Charge-Exchange Injection	collimation, injection, simulation, insertion	535
	S. Kato Tohoku University, Graduate School of Science, Sendai, Japan H. Harada, S. Hatakeyama, J. Kamiya, M. Kinsho, K. Yamamoto, Y. Yamazaki, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. In this process, we devised the method of angular regulation of collimator block. We present the method of angular regulation and performance of this new collimation system.

MOPPD075	Optimization of the Collimation System for the CSNS/RCS	collimation, closed-orbit, beam-losses, injection	538
	N. Wang, M.Y. Huang, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	Beam loss induced activation of the accelerator components is one of the primary concerns in designing a high intensity machine. The uncontrolled beam loss is required to be less than 1 W/m for hands-on maintenance of the machine. A two stage collimation system is designed in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) to localize the beam losses in a restricted area. The parameters of the collimator are optimized in order to obtain high collimation efficiency. The final design of the collimation system is presented. The reliability of the collimation system is estimated for different working points and with closed orbit errors.

MOPPD080	Improved Robustness of the LHC Collimation System by Operating with a Jaw-beam Angle	proton, collimation, radiation, alignment	553
	L. Lari, R.W. Assmann, A. Rossi CERN, Geneva, Switzerland M. Cauchi UoM, Msida, Malta A. Faus-Golfe, L. Lari IFIC, Valencia, Spain
	Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program. The robustness of the Phase I collimation system could be improved playing with the angular orientation of each single jaw. A preliminary study on the asymmetric misalignment of the collimator jaws, scanning through different jaw angles and varying beam sizes and energy, have been carried out, aiming at minimizing the energy deposited on metallic collimators, following an asynchronous dump.

MOPPD082	Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array	collimation, proton, collider, vacuum	559
	D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda Fermilab, Batavia, USA Y.A. Chesnokov, I.A. Yazynin IHEP, Moscow Region, Russia V. Guidi, A. Mazzolari INFN-Ferrara, Ferrara, Italy Yu.M. Ivanov PNPI, Gatchina, Leningrad District, Russia D. Mirarchi, S. Redaelli CERN, Geneva, Switzerland
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP). With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%.

MOPPP008	Hard X-ray Generation Experiment at Tsinghua Thomson Scattering X-Ray Source	laser, electron, photon, background	583
	Y.-C. Du, H. Chen, Q. Du, Hua, J.F. Hua, W.-H. Huang, H.J. Qian, C.-X. Tang, H.S. Xu, L.X. Yan, Z. Zhang TUB, Beijing, People's Republic of China
	Recently, there is increasing industrial and scientific interesting in ultra-fast, high peak brightness, tunable energy and polarization, monochromatic hard X-ray source. The X-ray source based on the Thomson scattering between the relativistic electron beam and TW laser pulse is the suitable candidate for its compact and affordable alternatives for high brightness hard monochromatic X-ray generation. Accelerator laboratory in Tsinghua University al so proposed and built Tsinghua Thomson scattering X-ray source. The hard x-ray pulse has been generated in experiment with 47 MeV electron and 20 TW laser in this year, and the parameters of the X-ray have been measured preliminarily. The experimental results are presented and discussed in this paper.

MOPPP009	X-Ray Spectra Reconstruction of Thomson Scattering Source From Analysis of Attenuation Data	photon, simulation, target, laser	586
	Y.-C. Du, Hua, J.F. Hua, W.-H. Huang, C.-X. Tang, H.S. Xu, L.X. Yan, H. Zha, Z. Zhang TUB, Beijing, People's Republic of China
	Thomson scattering X-ray source, in which the TW laser pulse is scattered by the relativistic electron beam, can provide ultra short, monochromatic, high flux, tunable polarized hard X-ray pulse which is can widely used in physical, chemical and biological process research, ultra-fast phase contrast imaging, and so on. Since the pulse duration of X-ray is as short as picosecond and the flux in one pulse is high, it is difficult to measure the x-ray spectrum. In this paper, we present the X-ray spectrum measurement experiment on Tsinghua Thomson scattering. The preliminary experimental results shows the maximum X-ray energy is about 47 keV, which is agree well with the simulations.

MOPPP049	Deposition and In-Situ Characterization of Alkali Antimonide Photocathodes	cathode, vacuum, synchrotron, diagnostics	670
	X. Liang SBU, Stony Brook, New York, USA K. Attenkofer ANL, Argonne, USA I. Ben-Zvi, M. Ruiz-Osés Stony Brook University, Stony Brook, USA H.A. Padmore, T. Vecchione LBNL, Berkeley, California, USA S.G. Schubert HZB, Berlin, Germany J. Smedley BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences of the U. S. Department of Energy, under Contract No. KC0407-ALSJNT-I0013, and DE-SC0005713. Alkali antimonide cathodes have the potential to provide high quantum efficiency for visible light, and are significantly more tolerant of vacuum contaminants than GaAs, so they are attractive for high-average-current photoinjectors to generate high quality electron beams. These cathodes are crystalline; however, standard growth recipes used today do not produce large crystals. We have grown multi-alkali cathodes on silicon and molybdenum substrates with in-situ X-ray diffraction (XRD) and X-ray reflection (XRR) analysis. The correlation of the cathode structure to the growth parameters and quantum efficiency was explored. During the deposition and evaporation of Sb and K layers, the possibility of selective growth of specific crystalline orientation was observed via X-ray diffraction.

MOPPR067	Simulations of Fast X-ray Detectors Based on Multichannel Plates	electron, photon, simulation, cathode	939
	Z. Insepov, B.W. Adams, J. Norem ANL, Argonne, USA V. Ivanov Muons, Inc, Batavia, USA
	Funding: Argonne National Laboratory High-performance detectors with high spatial and time resolutions are required for imaging of fast processes, time-resolved coherent scattering, and time-resolved x-ray spectroscopy. Recent developments in micro-channel plate (MCP) technology are important for sub-ns and 2d-spatially resolving x-ray detection. A Monte Carlo code was used to calculate the yields of secondary electrons emitted from a photo-cathode irradiated by X-rays, E=1-10 keV. Several photo-cathode materials were tested, including Al2O3, MgO, carbon, copper, WO3. The calculated emissive characteristics were used as input parameters of a second Monte Carlo code that was capable of calculating the gain/time characteristics of the MCP based X-Ray detector. A new type of X-Ray detector based on MCPs coated by resistive and emissive layers inside the pores by using atomic-layer deposition (ALD) promises a large parameter space where optimizations can take place. These optimizations for x-ray-specific applications are expected to improve the spatial resolution to 100 microns and the time resolution to 50 ps, and the development of high-quantum-yield photo-cathodes based on MCPs with grazing incidence inside the pores.

MOPPR079	Horizontal Beam-size Measurements at CESR-TA Using Synchrotron-light Interferometer	emittance, synchrotron, synchrotron-radiation, lattice	972
	S. Wang, J.V. Conway, D.L. Hartill, M.A. Palmer, D. L. Rubin CLASSE, Ithaca, New York, USA R.F. Campbell, R. Holtzapple CalPoly, San Luis Obispo, California, USA
	Funding: DOE Award DE-FC02-08ER41538 NSF Award (PHY-0734867) NSF Award (PHY-1002467) NSF Award (PHY-1068662). A horizontal beam profile monitor utilizing visible synchrotron radiation from a bending magnet has been designed and installed in CESR. The monitor employs a double-slit interferometer which has been successfully implemented to measure horizontal beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 microns can be measured with a resolution of approximately 5 microns. The method for extracting the horizontal beam size from the interference pattern is presented and its application to intrabeam scattering studies is described. A configuration for measuring the small vertical beam size is also discussed.

TUOBB01	A European Proposal for the Compton Gamma-ray Source of ELI-NP	laser, photon, electron, emittance	1086
	L. Serafini, I. Boscolo, F. Broggi, V. Petrillo Istituto Nazionale di Fisica Nucleare, Milano, Italy O. Adriani, G. Graziani, G. Passaleva INFN-FI, Sesto Fiorentino, Italy S. Albergo, A. Tricomi INFN-CT, Catania, Italy D. Alesini, M.P. Anania, A. Bacci, R. Bedogni, M. Bellaveglia, C. Biscari, R. Boni, M. Boscolo, M. Castellano, E. Chiadroni, A. Clozza, E. Di Pasquale, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, F. Marcellini, C. Maroli, G. Mazzitelli, E. Pace, L. Pellegrino, R. Ricci, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, P. Tomassini, C. Vaccarezza, S. Vescovi, F. Villa INFN/LNF, Frascati (Roma), Italy D. Angal-Kalinin, J.A. Clarke, B.D. Fell, A.R. Goulden, J.D. Herbert, S.P. Jamison, P.A. McIntosh, R.J. Smith, S.L. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P. Antici, M. Coppola, L. Lancia, A. Mostacci, L. Palumbo URLS, Rome, Italy N. Bliss, B.G. Martlew STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom P. Cardarelli, M. Gambaccini INFN-Ferrara, Ferrara, Italy L. Catani, A. Cianchi INFN-Roma II, Roma, Italy I. Chaikovska, O. Dadoun, A. Stocchi, A. Variola, Z.F. Zomer LAL, Orsay, France C. De Martinis INFN/LASA, Segrate (MI), Italy F. Druon, P. Fichot ILE, Palaiseau Cedex, France E. Iarocci University of Rome "La Sapienza", Rome, Italy M. Migliorati Rome University La Sapienza, Roma, Italy A.-S. Müller IN2P3, Paris, France V. Nardone Università di Roma I La Sapienza, Roma, Italy C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy M. Veltri Uniurb, Urbino (PU), Italy
	A European proposal is under preparation for the Compton gamma-ray Source of ELI-NP. In the Romanian pillar of ELI (the European Extreme Light Infrastructure) an advanced gamma-ray beam is foreseen, coupled to two 10 PW laser systems. The photons will be generated by Compton back-scattering in the collision between a high quality electron beam and a high power laser. A European collaboration formed by INFN, Univ. of Roma La Sapienza, Orsay-LAL of IN2P3, Univ. de Paris Sud XI and ASTeC at Daresbury, is preparing a TDR exploring the feasibility of a machine expected to achieve the Gamma-ray beam specifications: energy tunable between 1 and 20 MeV, narrow bandwidth (0.3%) and high spectral density, 10⁴ photons/sec/eV. We will describe the lay-out of the 720 MeV RF Linac and the collision laser with the associated optical cavity, as well as the optimized beam dynamics to achieve maximum phase space density at the collision, taking into account beam loading and beam break-up due to the acceleration of long bunch trains. The predicted gamma-ray spectra will be evaluated as the gamma photons collimators background. An option for electron bunches recirculation will also be illustrated.
	Slides TUOBB01 [5.099 MB]

TUOBC02	Small-Beta Collimation at SuperKEKB to Stop Beam-Gas Scattered Particles and to Avoid Transverse Mode Coupling Instability	interaction-region, impedance, coupling, simulation	1104
	H. Nakayama, Y. Funakoshi, K. Kanazawa, K. Ohmi, Y. Ohnishi, Y. Suetsugu KEK, Tsukuba, Japan H. Nakano Tohoku University, Graduate School of Science, Sendai, Japan
	At SuperKEKB, beam particles which are Coulomb-scattered by the residual gas molecular change direction and will be eventually lost by hitting beam pipe inner wall. Due to large vertical beta function and small beam pipe radius just before IP, most of Coulomb-scattered particles are lost there and are very dangerous for the Belle-II detector. To stop such particles before the IP, vertical collimators are installed in the ring. However, such vertical collimators should be placed very close (few mm) to the beam and therefore induce transverse mode coupling instability. To avoid beam instability and achieve collimation at the same time, we need to install vertical collimators where vertical beta function is SMALL, since maximum collimator width determined by aperture condition is proportional to β^1/2, and minimum collimator width determined by instability is proportional to β^2/3. We present our strategy to stop beam-gas scattered particles and simulated loss rate in the interaction region. We will also show dedicated vertical collimator design to achieve less instability.
	Slides TUOBC02 [2.196 MB]

TUPPC049	A Tapered-foil Emittance-exchange Experiment at LANSCE	emittance, proton, simulation, collimation	1278
	R.C. McCrady LANL, Los Alamos, New Mexico, USA
	We are planning an experiment at the Los Alamos Neutron Science Center (LANSCE) to demonstrate a technique for reducing the transverse emittance of the proton beam by passing the beam through a wedge-shaped energy degrader to produce a non-symplectic correlation between transverse position and energy, then removing this correlation with a bending magnet. This technique was proposed by Peterson* in 1983. We present a specific beamline layout that is expected to mitigate several complications associated with fielding an experiment to demonstrate the technique with a low-emittance proton beam. We present simulated results and expected outcomes of this demonstration. * J. M. Peterson, Proc. of PAC 1983, pP. 2403-2405 (1984).

TUPPC060	Beam Optics and the pp2pp Setup of the STAR Experiment at RHIC	quadrupole, proton, simulation, optics	1311
	P.H. Pile, W. Guryn, J.H. Lee, S. Tepikian, K. Yip BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The newly installed forward detector system at the STAR experiment at RHIC measures small angle elastic and inelastic scattering of polarized protons on polarized protons. The detector system makes use of a pair of Roman Pot (RP) detectors, instrumented with silicon detectors, and located on either side of the STAR intersection region downstream of the DX and D0 dipoles and quadrupole triplets. The parallel to point optics is designed so that scattering angles are determined from position measurements at the RP's with small error. The RP setup allows measurement of position and angle for a subset of the scattered protons. These measured position/angle correlations at the RP's can be compared with optics model predictions to get a measure of the accuracy of the quadrupole triplet current settings. The current in each quadrupole in the triplets is comprised of sums and differences of up to six power supplies and an overall 1% error in the triplet field strengths results in a 4% error in four-momentum transfer squared. This technique is also useful to check the polarity of the skew elements located in each quadrupole triplet. Results of the analysis will be presented.

TUPPD007	Multiple Scattering Measurements in the MICE Experiment	simulation, emittance, solenoid, factory	1419
	T. Carlisle, J.H. Cobb JAI, Oxford, United Kingdom D.V. Neuffer Fermilab, Batavia, USA
	The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test and characterize a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with a relative accuracy of 1% by measuring muons individually. Muon detectors include two scintillating fibre trackers embedded within 4 T solenoid fields, TOF counters and a muon ranger. Step IV of MICE will begin in 2012, producing the experiment's first precise emittance-reduction measurements. Multiple scattering in candidate Step IV absorber materials was studied in G4MICE, based on GEANT4. Equilibrium emittances for low-Z materials from hydrogen to aluminium can be studied experimentally in Step IV of MICE, and compared with simulations.

TUPPD014	To the Ionization Cooling in a RF Cavity with Absorber	cavity, focusing, radiation, emittance	1437
	A.A. Mikhailichenko CLASSE, Ithaca, New York, USA
	We are considering a RF cavity with Beryllium disk installed in the middle of the cavity as a ionization cooling element for the muon beam. Specially arranged shape of disk together with nonzero dispersion allows 6D cooling of muon beam. Technical aspects of this system and conceptual design are discussed in this paper also. This type of cooler demonstrates advantages if compared with the RF cavity filled with pressurized gas or with the helical cooler.

TUPPD016	Collection Optics with the Horn Type Focusing Element made with Separate Conductors	focusing, positron, secondary-beams, optics	1443
	A.A. Mikhailichenko CLASSE, Ithaca, New York, USA
	We describe the device for focusing of charged particles by the system of separated conductors which follow the parabolic profile. Basically this is a horn-type focuser, but with the individual conductors instead of continuous surface. This device allows substantial reduction of fabrication cost with the same focusing properties as the continuous parabolic surface. We recommend this “bird-cage” type system for focusing pions/muons in the projects under discussion in many Laboratories around the World.

TUPPR007	Beam Background and MDI Design for SuperKEKB/Belle-II	background, luminosity, neutron, radiation	1825
	H. Nakayama, M. Iwasaki, K. Kanazawa, Y. Ohnishi, S. Tanaka, T. Tsuboyama KEK, Tsukuba, Japan H. Nakano Tohoku University, Graduate School of Science, Sendai, Japan
	The Belle experiment, operated at the asymmetric electron-positron collider KEKB, had accumulated a data sample with an integrated luminosity of more than 1 ab⁻¹ before the shutdown in June 2010. We have started upgrading both the accelerator and the detector, SuperKEKB and Belle-II, to achieve the target luminosity of 8×10³⁵ cm⁻² s⁻¹. With the increased luminosity, the beam background will be severe. The development of Machine- Detector Interface (MDI) design is crucial to cope with the increased background and protect Belle-II detector. We will present the estimation of impact from each beam background sources at SuperKEKB, such as Touschek-scattering, Beam-gas scattering, radiative Bhabha process, etc.. We will also present our countermeasures against them, such as collimators to stop scattered beam particles, Tungsten shield to protect inner detectors from shower particles, and dedicated beam pipe design around interaction point to stop synchrotron radiation, etc.

TUPPR020	Updates to the CLIC Post-collision Line	simulation, radiation, shielding, background	1855
	L.C. Deacon CERN, Geneva, Switzerland
	The 1.5 TeV Compact Linear Collider (CLIC) beams, with a total power of 14 MW per beam, are disrupted at the interaction point due to the very strong beam-beam effect. The disrupted beam has a power of 10 MW. Some 3.5 MW reaches the main dump in the form of beamstrahlung photons, and about 0.5 MW of e⁺ and e^- coherent pair particles with a very broad energy spectrum as well as the lower energy disrupted beam particles need to be disposed of along the post collision line. Calculations for the energy deposition in the magnet coils and the resulting magnet lifetimes for various shielding configurations are presented.

TUPPR057	Intrabeam Scattering Studies at the Swiss Light Source	emittance, damping, storage-ring, monitoring	1951
	F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland M. Aiba, M. Böge, N. Milas, A. Streun Paul Scherrer Institut, Villigen, Switzerland T. Demma INFN/LNF, Frascati (Roma), Italy
	The target parameters of modern ultra-low emittance rings are entering into a regime where intra-beam scattering (IBS) becomes important and, in the case of linear collider damping rings, even a limitation for the delivered emittances. The Swiss Light Source (SLS) storage ring, as it has achieved a vertical geometrical emittance of around 2 pm at 2.4 GeV, and it has the ability to run at even lower energies, and the availability of emittance monitoring diagnostics, is an ideal test bed for IBS studies. Simulations using the classical IBS theories and tracking codes are undertaken in order to explore the possibilities and limitations for IBS measurements at the SLS. In this respect, comparison between the theories and codes is first discussed. The dependence of the output emittances, taking into account the effect of IBS, with respect to energy, bunch charge and zero current vertical and longitudinal emittance is also studied, in order to define the regimes where the IBS effect can be significant. First measurement results from the SLS running at lower energies are finally presented.

WEPPD055	Gamma-rays Generation with 3D 4-mirror Cavity for ILC Polarized Positron Source	cavity, laser, photon, electron	2645
	T. Akagi, S. Miyoshi Hiroshima University, Graduate School of Advanced Sciences of Matter, Higashi-Hiroshima, Japan S. Araki, Y. Funahashi, Y. Honda, T. Okugi, T. Omori, H. Shimizu, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan H. Kataoka, T. Kon Seikei University, Japan M. Kuriki, T. Takahashi Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan K. Sakaue, M. Washio RISE, Tokyo, Japan R. Tanaka, H. Yoshitama Hiroshima University, Higashi-Hiroshima, Japan
	We are conducting gamma-rays generation experiment by the laser-Compton scattering using a Fabry-Perot cavity. We developed a 3D 4-mirror cavity, and it is installed at the KEK-ATF. By using a 3D 4-mirror cavity, small laser spot can be achieved with stable resonant condition. In addition, we aim 1900 times enhancement of input laser power by a 4-mirror cavity to increase the number of gamma-rays.

WEPPD062	Measurements of the First RF Prototype of the Spiral2 Single Bunch Selector	vacuum, impedance, high-voltage, simulation	2663
	M. Di Giacomo GANIL, Caen, France A.C. Caruso, F. Consoli, G. Gallo, D. Rifuggiato, E. Zappalà INFN/LNS, Catania, Italy A. Longhitano ALTEK, San Gregorio (CATANIA), Italy
	Funding: Work supported by EU commission 7th framework project n. 212692. The single bunch selector of the Spiral2 driver uses 100 Ω travelling wave electrodes driven by fast pulse generators. A 2.5 kV, 1 kW feed-through and a vacuum chamber housing the water cooled electrodes have been designed and built. The paper reviews the whole design and reports the results of first RF and power measurements.

WEPPD065	Development of a Laser-based Alignment System Utilizing Fresnel Zone Plates at the KEKB Injector Linac	laser, alignment, linac, focusing	2672
	T. Suwada, M. Satoh KEK, Ibaraki, Japan K. Minoshima, S. Telada AIST, Tsukuba, Japan
	A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the 600-m-long KEKB injector linac. A well-known sequential three-point method with Fresnel zone plates and a CCD camera is revisited in the alignment system. The high-precision alignment system is strongly required in order to stably accelerate high-brightness electron and positron beams with high bunch charges and also to keep the beam stability with higher quality towards the Super B-factory at KEK. A new laser optics has been developed and the laser propagation characteristics has been systematically investigated at a 100-m-long straight section in vacuum. In this report, the experimental developments and investigations are reported along with the design of the new laser-based alignment system.

WEPPR015	Intrabeam Scattering Studies at CesrTA	emittance, electron, positron, lattice	2970
	M. P. Ehrlichman Cornell University, Ithaca, New York, USA F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland W. Hartung, M.A. Palmer, D.P. Peterson, N.T. Rider, D. L. Rubin, J.P. Shanks, C.R. Strohman, S. Wang CLASSE, Ithaca, New York, USA R. Holtzapple CalPoly, San Luis Obispo, California, USA
	Funding: NSF Award (PHY-0734867) NSF Award (PHY-1002467) Japan/US Cooperation Program Education and lifelong learning, co-financed by Greece and the European Union Intrabeam scattering dilutes the emittance of low energy, low emittance rings. Because CesrTA can be operated at low energies with low transverse emittances and high bunch intensity, it is an ideal laboratory for the study of IBS effects. Furthermore, CesrTA is instrumented for accurate beam size measurements in all three dimensions, providing the possibility of a complete determination of the intensity dependence of emittances. Models based on classical IBS theories and multi-particle simulations are used to estimate the effect of IBS at CesrTA at different beam emittances, intensities and energies. The first measurements from machine studies at CesrTA are presented.

WEPPR028	An Estimate of Out of Time Beam Upon Extraction for Mu2e	septum, extraction, proton, background	2994
	N.J. Evans, S.E. Kopp The University of Texas at Austin, Austin, Texas, USA E. Prebys Fermilab, Batavia, USA
	Funding: U.S. Dept. of Energy. A bunched beam with specific structure is crucial to attaining the experimental sensitivity desired by the Mu2e collaboration. The final goal is a ratio of in-time to out-of-time beam, known as beam extinction, of 10^-10. An AC dipole system is in development to attain the final goal by sweeping out-of-time beam onto a collimation system, but it is still necessary to achieve something on the order of 10^-5 when beam is extracted from the Fermilab Debuncher ring to the experiment hall. Several sources of out-of-time beam in the Debuncher ring are analyzed, including: intrabeam scattering, RF noise, beam-gas interaction and scattering off of the extraction septum. Estimates are given for each source as well as a final estimate of total out-of-time beam expected upon extraction.

WEPPR086	Computed Wake Field Effects from Measured Surface Roughness in the Walls of the Cornell ERL	wakefield, vacuum, undulator, impedance	3132
	M.G. Billing, G.H. Hoffstaetter, C.E. Mayes, K.W. Smolenski, H.A. Williams CLASSE, Ithaca, New York, USA
	Funding: Work supported by the NSF ERL Phase 1B Cooperative Agreement (DMR-0807731) Wake fields arise from the discontinuities in a smooth vacuum chamber and will cause energy spread in the passing bunch. In an energy recovery linac (ERL), the spent bunches are decelerated before they are dumped to reuse the beam’s energy for the acceleration of new bunches. While the energy spread accumulated from wakes before deceleration is small compared to the beam’s energy after full acceleration, it becomes more important relatively as the beam’s energy decreases.* Thus, in an ERL wake fields can produce very significant energy spread in the beam as it is decelerated to the energy of the beam dump. We report on calculations of wake fields due to the roughness of the surface of the vacuum chamber walls as it affects the Cornell ERL design. These calculations include the effects from the measured roughness for real vacuum chamber wall surfaces. * M. Billing, “Effect of Wake Fields in an Energy Recovery Linac”, PAC’09, Vancouver, BC, Canada, 4-8 May 2009.

THPPD041	Evaluation and Implementation of High Performance Real-Time Signal Processing For Rayleigh Scattering Based Quench Detection for High Field Superconducting Magnets	solenoid, LabView, simulation, superconducting-magnet	3602
	G. Flanagan, R.P. Johnson Muons, Inc, Batavia, USA W.K. Chan, J. Schwartz North Carolina State University, Raleigh, North Carolina, USA Q. Ruan, D. Schmidt, L. Wenzel, C. Wimmer National Instruments, Austin, USA
	Funding: Supported in part by SBIR Grant 4747 · 11SC06251 YBCO coated conductors are one of the primary options for generating the high magnetic fields needed for future high energy physics devices. Due to slow quench propagation, quench detection remains one of the primary limitations to YBCO magnets. Fiber optic sensing, based upon Rayleigh scattering, has the potential for quench detection with high spatial resolution. This paper discusses the potential of multicore CPU's and FPGA’s to accelerate the signal processing demands associated with Rayleigh scattering based quench detection systems in a real-time environment.

THPPP070	Comparison of the Residual Doses Before and After Resumption of User Operation in J-PARC RCS	injection, alignment, target, neutron	3901
	K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, M. Kinsho, R. Saeki, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	J-PARC Facilities were damaged by East Japan Earthquake in March 2011, but All Facirities resumed a beam operation from December 2012. In this paper, we report and compare the beam loss distribution and the residual doses before and after resumption of user operation in J-PARC RCS.

THPPR032	A Split-Electrode for Clearing Scattered Electrons in the RHIC E-Lens	electron, proton, ion, solenoid	4038
	X. Gu, W. Fischer, D.M. Gassner, K. Hamdi, J. Hock, Y. Luo, C. Montag, M. Okamura, A.I. Pikin, P. Thieberger 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. We are designing two electron lenses that will be installed at RHIC IR10 to compensate for the head-on beam-beam effect. To clear accumulated scattered electrons from 100 GeV proton-electron head-on collisions in the e-lens, a clearing split electrode may be constructed. The feasibility of this proposed electrode was demonstrated via the CST Particle Studio and Opera program simulations. By splitting one of the drift tubes in the e-lens and applying ~ 380 V across the two parts, the scattered electrons can be cleared out within several hundred micro-seconds. At the same time we can restrict the unwanted shift of the primary electron-beam that already passed the 2-m interaction region in e-lens, to less than 15um.

THPPR042	Optimisation of an Inverse Compton Scattering Experiment with a Real Time Detection Scheme Based on a Radio Luminescent Screen and Comparison of the X-rays Beam Characteristics with Simulations	electron, photon, laser, emittance	4068
	A.S. Chauchat, JP. Brasile TCS, Colombes, France A. Binet, V. Le Flanchec, J-P. Nègre CEA/DAM/DIF, Arpajon, France J.-M. Ortega LCP/CLIO, Orsay, Cedex, France
	To optimize the detection of an 11-keV X-Ray beam produced by Inverse Compton Scattering at the ELSA facility, with a 17 MeV electron beam and a 532 nm laser, we demonstrate the use of a very sensitive detection scheme, based on a radio luminescent screen used in the spontaneous emission regime. It has proven to be very sensitive and very effective to detect 11-keV X-Rays while rejecting the overall ambient noise produced in a harder spectral range. It allowed us to optimize the electron-photon interaction probability by observing in real time the effect of both beams transport parameters. We could then compare simulation results with experimental measurements that appear to be in good agreement. A.S. Chauchat et al. Instrumentation developments for production and characterization of Inverse Compton Scattering X-rays and first results with a 17 MeV electron beam, NIMA, V.622, I.1, P.129-135

THPPR061	Optimisation Studies of Accelerator Driven Fertile to Fissile Conversion Rates in Thorium Fuel Cycle	proton, neutron, simulation, target	4112
	C. Bungau, R.J. Barlow, R. Cywinski University of Huddersfield, Huddersfield, United Kingdom
	The need for proliferation-resistance, longer fuel cycles, higher burn up and improved waste form characteristics has led to a renewed worldwide interest in thorium-based fuels and fuel cycles. In this paper the GEANT4 Monte Carlo code has been used to simulate the Thorium-Uranium fuel cycle. The accelerator driven fertile to fissile conversion rates have been calculated for various geometries. Several new classes have been added by the authors to the GEANT4 simulation code, an extension which allows the state-of-the-art code to be used for the first time for nuclear reactor criticality calculations.

THPPR068	Laser Compton Scattering X-rays as a Tool for K-edge Densitometry	photon, laser, electron, radiation	4133
	M. Titberidze, K. Chouffani IAC, Pocatello, IDAHO, USA
	There is a huge interest in bright and tunable X-ray sources. These sources can be used in various research fields, including medical, biological and industrial fields. Laser Compton Scattering (LCS) technique gives us possibility to generate tunable, quasi monochromatic and polarized X-ray beam. One of the applications of LCS is the detection and quantitative identification of special nuclear materials (SNM) using K-edge densitometry(KED)method. Our group was the first one who has used a quasi-monochromatic LCS source to carry out KED experiments. The experiments showed that LCS technique could be used for SNM detection and quantification.

THPPR075	The UK MEIS Facility : A New Future	ion, target, quadrupole, alignment	4151
	R.J. Barlow University of Huddersfield, Huddersfield, United Kingdom
	The Medium Energy Ion Scattering facility at the Daresbury Laboratory, one of only ~10 such facilities in the world, has served the UK community since 1996. It provides a 50-400 keV ion beam and a very comprehensive experimental station where samples can be studied and the energies and angles of the recoil ions measured. It is now closing, but will be be relocated some 50 miles to the University of Huddersfield: it should be recommissioned and available to users in early 2012. We will report on progress, and on the facilities which will be available for users at the new site and under the new management.

Paper

Title

Other Keywords

Page

MOPPC007

Plans for High Beta Optics in the LHC

optics, quadrupole, emittance, insertion

133

H. Burkhardt, A. Macpherson
CERN, Geneva, Switzerland
S. Cavalier, P.M. Puzo
LAL, Orsay, France

Based on what has been learned with the first high β^* = 90 m operation in 2011, we describe the potential and practical scenarios for reaching very high β^* in the LHC in 2012 and beyond. Very high β^* optics require dedicated running time and conditions in the LHC. We describe a plan which is optimized to maximize the physics potential in a minimum of dedicated running time.

MOPPC008

LHC Optics Determination with Proton Tracks Measured in the Roman Pots Detectors of the TOTEM Experiment

proton, optics, lattice, coupling

136

H. Niewiadomski, H. Burkhardt
CERN, Geneva, Switzerland
F.J. Nemes
KFKI, Budapest, Hungary

The TOTEM experiment at the LHC is equipped with near beam movable devices – called Roman Pots (RP) – which detect protons scattered at the interaction point (IP) arrived to the detectors through the magnet lattice of the LHC. Proton kinematics at IP is reconstructed from positions and angles measured by the RP detectors, on the basis of the optical functions between IP and the RP locations. The precision of optics determination is therefore of the key importance for the experiment. TOTEM developed a novel method of machine optics determination making use of angle-position distributions of elastically scattered protons observed in the RP detectors. The method has been successfully applied to the data samples registered in 2010 and 2011. The studies have shown that the transport matrix could be estimated with a precision better than 1%.

MOPPD009

Stochastic Cooling Developments for HESR at FAIR

target, ion, heavy-ion, emittance

388

H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen
FZJ, Jülich, Germany
C. Dimopoulou, A. Dolinskii, T. Katayama, Yu.A. Litvinov, M. Steck, T. Stöhlker
GSI, Darmstadt, Germany

The High-Energy Storage Ring (HESR) is part of the upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. The HESR is planned to dedicate to the field of high-energy antiproton physics to explore the research areas of charmonium spectroscopy, hadronic structure, and quark-gluon dynamics with high-quality beams over a broad momentum range from 1.5 to 15 GeV/c. The new facility provides the combination of powerful phase-space cooled antiproton beams and internal Pellet and gas jet targets to achieve the requirements of the experiment PANDA in terms of beam quality and luminosity. Detailed theoretical analyses have been carried out to design the stochastic cooling system for accumulation and stochastic cooling of antiprotons with target operation. Recently it is proposed to utilize the HESR also for the atomic and nuclear physics with highly charged heavy ions such as 132Sn⁵⁰⁺ in the dedicated experiments at high energies 0.74-3 GeV/u. In this contribution the feasibility of stochastic cooling of heavy ions with internal targets is in detail investigated under the constraint of the cooling system hardware as foreseen for anti-proton cooling.

MOPPD052

Study of Electrostatic Septum by Low-Z Material for High Intensity Proton Beam

septum, extraction, proton, beam-losses

484

D. Horikawa
Sokendai, Ibaraki, Japan
Y. Arakaki, K. Okamura, Y. Shirakabe, M. Tomizawa
KEK, Ibaraki, Japan
I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan
T. Shimogawa
Saga University, Faculty of Science and Engineering, Saga, Japan

In a high-intensity proton accelerator, the beam loss at the time of late beam extraction causes radioactivation of apparatus. It takes out and is a problem serious to that of upper about beam power. Its attention was paid to electric septum (ESS) of the equipment used for beam extraction for problem solving. The septum section of ESS which beam hits directly is usually used for tungsten. Therefore, it is low atomic number material to the septum section. Development of the new model ESS using the textile material carbon fiber of a certain carbon (CF) was started. Is it a problem in CF at processability? Is it using for the septum section of ESS for a certain reason? Difficult it was. Therefore, it succeeded in obtaining required form and intensity by developing the twisting thread technology of CF. Moreover, the tension strength test of CFwire and the pyrogenicity test by electric current were done. Is it the tension intensity and heat durability which exceed the existing tungsten wire? It was confirmed. In addition to the ESS development technique using these new materials, and a result, a future measure is reported.

MOPPD064

Simulation of Double Layer Carbon Stripping Foils for ISIS Injection Upgrades

injection, simulation, radiation, proton

514

H. V. Smith, D.J. Adams, B. Jones, C.M. Warsop
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
Y. Irie, Y. Takeda
KEK, Ibaraki, Japan

ISIS, the pulsed neutron and muon spallation source located at the Rutherford Appleton Laboratory (UK), currently delivers a mean beam power of 0.2 MW to target. A 70 MeV H linear accelerator feeds into a 50 Hz, 800 MeV proton synchrotron, accelerating up to 3·10¹³ protons per pulse. Potential injection scheme upgrades, aiming to raise average beam power towards 0.5 MW with a new 180 MeV linear accelerator, continue to be studied. This paper highlights recent results from temperature studies of double layer carbon foils, suitable for injection at 180 MeV into ISIS, using ANSYS. Experimental data from KEK was used to benchmark models and the variation of temperature as a function of foil separation was considered.

MOPPD067

Novel Slow Extraction Scheme for Proton Accelerators Using Pulsed Dipole Correctors and Crystals

extraction, septum, proton, betatron

517

V.D. Shiltsev
Fermilab, Batavia, USA

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359
Slow extraction of protons beams from circular accelerators is currently widely used for a variety of beam-based experiments. The method has some deficiencies including limited efficiency of extraction, radiation induced due to scattering on the electrostatic septa and limited beam pipe aperture, beam dynamics effects of space charge forces and magnet power supplies ripple. Here we present a novel slow extraction scheme employing a number of non-standard accelerator elements, such as Silicone crystal strips and pulsed strip-line dipole correctors, and illustrate practicality of these examples at the 8 GeV proton Recycler Ring at Fermilab.

MOPPD074

Localization of Large Angle Foil Scattering Beam Loss Caused by Multi-Turn Charge-Exchange Injection

collimation, injection, simulation, insertion

535

S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan
H. Harada, S. Hatakeyama, J. Kamiya, M. Kinsho, K. Yamamoto, Y. Yamazaki, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. In this process, we devised the method of angular regulation of collimator block. We present the method of angular regulation and performance of this new collimation system.

MOPPD075

Optimization of the Collimation System for the CSNS/RCS

collimation, closed-orbit, beam-losses, injection

538

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

Beam loss induced activation of the accelerator components is one of the primary concerns in designing a high intensity machine. The uncontrolled beam loss is required to be less than 1 W/m for hands-on maintenance of the machine. A two stage collimation system is designed in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) to localize the beam losses in a restricted area. The parameters of the collimator are optimized in order to obtain high collimation efficiency. The final design of the collimation system is presented. The reliability of the collimation system is estimated for different working points and with closed orbit errors.

MOPPD080

Improved Robustness of the LHC Collimation System by Operating with a Jaw-beam Angle

proton, collimation, radiation, alignment

553

L. Lari, R.W. Assmann, A. Rossi
CERN, Geneva, Switzerland
M. Cauchi
UoM, Msida, Malta
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain

Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program.
The robustness of the Phase I collimation system could be improved playing with the angular orientation of each single jaw. A preliminary study on the asymmetric misalignment of the collimator jaws, scanning through different jaw angles and varying beam sizes and energy, have been carried out, aiming at minimizing the energy deposited on metallic collimators, following an asynchronous dump.

MOPPD082

Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array

collimation, proton, collider, vacuum

559

D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda
Fermilab, Batavia, USA
Y.A. Chesnokov, I.A. Yazynin
IHEP, Moscow Region, Russia
V. Guidi, A. Mazzolari
INFN-Ferrara, Ferrara, Italy
Yu.M. Ivanov
PNPI, Gatchina, Leningrad District, Russia
D. Mirarchi, S. Redaelli
CERN, Geneva, Switzerland

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP).
With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%.

MOPPP008

Hard X-ray Generation Experiment at Tsinghua Thomson Scattering X-Ray Source

laser, electron, photon, background

583

Y.-C. Du, H. Chen, Q. Du, Hua, J.F. Hua, W.-H. Huang, H.J. Qian, C.-X. Tang, H.S. Xu, L.X. Yan, Z. Zhang
TUB, Beijing, People's Republic of China

Recently, there is increasing industrial and scientific interesting in ultra-fast, high peak brightness, tunable energy and polarization, monochromatic hard X-ray source. The X-ray source based on the Thomson scattering between the relativistic electron beam and TW laser pulse is the suitable candidate for its compact and affordable alternatives for high brightness hard monochromatic X-ray generation. Accelerator laboratory in Tsinghua University al so proposed and built Tsinghua Thomson scattering X-ray source. The hard x-ray pulse has been generated in experiment with 47 MeV electron and 20 TW laser in this year, and the parameters of the X-ray have been measured preliminarily. The experimental results are presented and discussed in this paper.

MOPPP009

X-Ray Spectra Reconstruction of Thomson Scattering Source From Analysis of Attenuation Data

photon, simulation, target, laser

586

Y.-C. Du, Hua, J.F. Hua, W.-H. Huang, C.-X. Tang, H.S. Xu, L.X. Yan, H. Zha, Z. Zhang
TUB, Beijing, People's Republic of China

Thomson scattering X-ray source, in which the TW laser pulse is scattered by the relativistic electron beam, can provide ultra short, monochromatic, high flux, tunable polarized hard X-ray pulse which is can widely used in physical, chemical and biological process research, ultra-fast phase contrast imaging, and so on. Since the pulse duration of X-ray is as short as picosecond and the flux in one pulse is high, it is difficult to measure the x-ray spectrum. In this paper, we present the X-ray spectrum measurement experiment on Tsinghua Thomson scattering. The preliminary experimental results shows the maximum X-ray energy is about 47 keV, which is agree well with the simulations.

MOPPP049

Deposition and In-Situ Characterization of Alkali Antimonide Photocathodes

cathode, vacuum, synchrotron, diagnostics

670

X. Liang
SBU, Stony Brook, New York, USA
K. Attenkofer
ANL, Argonne, USA
I. Ben-Zvi, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA
H.A. Padmore, T. Vecchione
LBNL, Berkeley, California, USA
S.G. Schubert
HZB, Berlin, Germany
J. Smedley
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences of the U. S. Department of Energy, under Contract No. KC0407-ALSJNT-I0013, and DE-SC0005713.
Alkali antimonide cathodes have the potential to provide high quantum efficiency for visible light, and are significantly more tolerant of vacuum contaminants than GaAs, so they are attractive for high-average-current photoinjectors to generate high quality electron beams. These cathodes are crystalline; however, standard growth recipes used today do not produce large crystals. We have grown multi-alkali cathodes on silicon and molybdenum substrates with in-situ X-ray diffraction (XRD) and X-ray reflection (XRR) analysis. The correlation of the cathode structure to the growth parameters and quantum efficiency was explored. During the deposition and evaporation of Sb and K layers, the possibility of selective growth of specific crystalline orientation was observed via X-ray diffraction.

MOPPR067

Simulations of Fast X-ray Detectors Based on Multichannel Plates

electron, photon, simulation, cathode

939

Z. Insepov, B.W. Adams, J. Norem
ANL, Argonne, USA
V. Ivanov
Muons, Inc, Batavia, USA

Funding: Argonne National Laboratory
High-performance detectors with high spatial and time resolutions are required for imaging of fast processes, time-resolved coherent scattering, and time-resolved x-ray spectroscopy. Recent developments in micro-channel plate (MCP) technology are important for sub-ns and 2d-spatially resolving x-ray detection. A Monte Carlo code was used to calculate the yields of secondary electrons emitted from a photo-cathode irradiated by X-rays, E=1-10 keV. Several photo-cathode materials were tested, including Al2O3, MgO, carbon, copper, WO3. The calculated emissive characteristics were used as input parameters of a second Monte Carlo code that was capable of calculating the gain/time characteristics of the MCP based X-Ray detector. A new type of X-Ray detector based on MCPs coated by resistive and emissive layers inside the pores by using atomic-layer deposition (ALD) promises a large parameter space where optimizations can take place. These optimizations for x-ray-specific applications are expected to improve the spatial resolution to 100 microns and the time resolution to 50 ps, and the development of high-quantum-yield photo-cathodes based on MCPs with grazing incidence inside the pores.

MOPPR079

Horizontal Beam-size Measurements at CESR-TA Using Synchrotron-light Interferometer

emittance, synchrotron, synchrotron-radiation, lattice

972

S. Wang, J.V. Conway, D.L. Hartill, M.A. Palmer, D. L. Rubin
CLASSE, Ithaca, New York, USA
R.F. Campbell, R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: DOE Award DE-FC02-08ER41538 NSF Award (PHY-0734867) NSF Award (PHY-1002467) NSF Award (PHY-1068662).
A horizontal beam profile monitor utilizing visible synchrotron radiation from a bending magnet has been designed and installed in CESR. The monitor employs a double-slit interferometer which has been successfully implemented to measure horizontal beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 microns can be measured with a resolution of approximately 5 microns. The method for extracting the horizontal beam size from the interference pattern is presented and its application to intrabeam scattering studies is described. A configuration for measuring the small vertical beam size is also discussed.

TUOBB01

A European Proposal for the Compton Gamma-ray Source of ELI-NP

laser, photon, electron, emittance

1086

L. Serafini, I. Boscolo, F. Broggi, V. Petrillo
Istituto Nazionale di Fisica Nucleare, Milano, Italy
O. Adriani, G. Graziani, G. Passaleva
INFN-FI, Sesto Fiorentino, Italy
S. Albergo, A. Tricomi
INFN-CT, Catania, Italy
D. Alesini, M.P. Anania, A. Bacci, R. Bedogni, M. Bellaveglia, C. Biscari, R. Boni, M. Boscolo, M. Castellano, E. Chiadroni, A. Clozza, E. Di Pasquale, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, F. Marcellini, C. Maroli, G. Mazzitelli, E. Pace, L. Pellegrino, R. Ricci, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, P. Tomassini, C. Vaccarezza, S. Vescovi, F. Villa
INFN/LNF, Frascati (Roma), Italy
D. Angal-Kalinin, J.A. Clarke, B.D. Fell, A.R. Goulden, J.D. Herbert, S.P. Jamison, P.A. McIntosh, R.J. Smith, S.L. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P. Antici, M. Coppola, L. Lancia, A. Mostacci, L. Palumbo
URLS, Rome, Italy
N. Bliss, B.G. Martlew
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
P. Cardarelli, M. Gambaccini
INFN-Ferrara, Ferrara, Italy
L. Catani, A. Cianchi
INFN-Roma II, Roma, Italy
I. Chaikovska, O. Dadoun, A. Stocchi, A. Variola, Z.F. Zomer
LAL, Orsay, France
C. De Martinis
INFN/LASA, Segrate (MI), Italy
F. Druon, P. Fichot
ILE, Palaiseau Cedex, France
E. Iarocci
University of Rome "La Sapienza", Rome, Italy
M. Migliorati
Rome University La Sapienza, Roma, Italy
A.-S. Müller
IN2P3, Paris, France
V. Nardone
Università di Roma I La Sapienza, Roma, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy
M. Veltri
Uniurb, Urbino (PU), Italy

A European proposal is under preparation for the Compton gamma-ray Source of ELI-NP. In the Romanian pillar of ELI (the European Extreme Light Infrastructure) an advanced gamma-ray beam is foreseen, coupled to two 10 PW laser systems. The photons will be generated by Compton back-scattering in the collision between a high quality electron beam and a high power laser. A European collaboration formed by INFN, Univ. of Roma La Sapienza, Orsay-LAL of IN2P3, Univ. de Paris Sud XI and ASTeC at Daresbury, is preparing a TDR exploring the feasibility of a machine expected to achieve the Gamma-ray beam specifications: energy tunable between 1 and 20 MeV, narrow bandwidth (0.3%) and high spectral density, 10⁴ photons/sec/eV. We will describe the lay-out of the 720 MeV RF Linac and the collision laser with the associated optical cavity, as well as the optimized beam dynamics to achieve maximum phase space density at the collision, taking into account beam loading and beam break-up due to the acceleration of long bunch trains. The predicted gamma-ray spectra will be evaluated as the gamma photons collimators background. An option for electron bunches recirculation will also be illustrated.

Slides TUOBB01 [5.099 MB]

TUOBC02

Small-Beta Collimation at SuperKEKB to Stop Beam-Gas Scattered Particles and to Avoid Transverse Mode Coupling Instability

interaction-region, impedance, coupling, simulation

1104

H. Nakayama, Y. Funakoshi, K. Kanazawa, K. Ohmi, Y. Ohnishi, Y. Suetsugu
KEK, Tsukuba, Japan
H. Nakano
Tohoku University, Graduate School of Science, Sendai, Japan

At SuperKEKB, beam particles which are Coulomb-scattered by the residual gas molecular change direction and will be eventually lost by hitting beam pipe inner wall. Due to large vertical beta function and small beam pipe radius just before IP, most of Coulomb-scattered particles are lost there and are very dangerous for the Belle-II detector. To stop such particles before the IP, vertical collimators are installed in the ring. However, such vertical collimators should be placed very close (few mm) to the beam and therefore induce transverse mode coupling instability. To avoid beam instability and achieve collimation at the same time, we need to install vertical collimators where vertical beta function is SMALL, since maximum collimator width determined by aperture condition is proportional to β^1/2, and minimum collimator width determined by instability is proportional to β^2/3. We present our strategy to stop beam-gas scattered particles and simulated loss rate in the interaction region. We will also show dedicated vertical collimator design to achieve less instability.

Slides TUOBC02 [2.196 MB]

TUPPC049

A Tapered-foil Emittance-exchange Experiment at LANSCE

emittance, proton, simulation, collimation

1278

R.C. McCrady
LANL, Los Alamos, New Mexico, USA

We are planning an experiment at the Los Alamos Neutron Science Center (LANSCE) to demonstrate a technique for reducing the transverse emittance of the proton beam by passing the beam through a wedge-shaped energy degrader to produce a non-symplectic correlation between transverse position and energy, then removing this correlation with a bending magnet. This technique was proposed by Peterson* in 1983. We present a specific beamline layout that is expected to mitigate several complications associated with fielding an experiment to demonstrate the technique with a low-emittance proton beam. We present simulated results and expected outcomes of this demonstration.
* J. M. Peterson, Proc. of PAC 1983, pP. 2403-2405 (1984).

TUPPC060

Beam Optics and the pp2pp Setup of the STAR Experiment at RHIC

quadrupole, proton, simulation, optics

1311

P.H. Pile, W. Guryn, J.H. Lee, S. Tepikian, K. Yip
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The newly installed forward detector system at the STAR experiment at RHIC measures small angle elastic and inelastic scattering of polarized protons on polarized protons. The detector system makes use of a pair of Roman Pot (RP) detectors, instrumented with silicon detectors, and located on either side of the STAR intersection region downstream of the DX and D0 dipoles and quadrupole triplets. The parallel to point optics is designed so that scattering angles are determined from position measurements at the RP's with small error. The RP setup allows measurement of position and angle for a subset of the scattered protons. These measured position/angle correlations at the RP's can be compared with optics model predictions to get a measure of the accuracy of the quadrupole triplet current settings. The current in each quadrupole in the triplets is comprised of sums and differences of up to six power supplies and an overall 1% error in the triplet field strengths results in a 4% error in four-momentum transfer squared. This technique is also useful to check the polarity of the skew elements located in each quadrupole triplet. Results of the analysis will be presented.

TUPPD007

Multiple Scattering Measurements in the MICE Experiment

simulation, emittance, solenoid, factory

1419

T. Carlisle, J.H. Cobb
JAI, Oxford, United Kingdom
D.V. Neuffer
Fermilab, Batavia, USA

The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test and characterize a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with a relative accuracy of 1% by measuring muons individually. Muon detectors include two scintillating fibre trackers embedded within 4 T solenoid fields, TOF counters and a muon ranger. Step IV of MICE will begin in 2012, producing the experiment's first precise emittance-reduction measurements. Multiple scattering in candidate Step IV absorber materials was studied in G4MICE, based on GEANT4. Equilibrium emittances for low-Z materials from hydrogen to aluminium can be studied experimentally in Step IV of MICE, and compared with simulations.

TUPPD014

To the Ionization Cooling in a RF Cavity with Absorber

cavity, focusing, radiation, emittance

1437

A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA

We are considering a RF cavity with Beryllium disk installed in the middle of the cavity as a ionization cooling element for the muon beam. Specially arranged shape of disk together with nonzero dispersion allows 6D cooling of muon beam. Technical aspects of this system and conceptual design are discussed in this paper also. This type of cooler demonstrates advantages if compared with the RF cavity filled with pressurized gas or with the helical cooler.

TUPPD016

Collection Optics with the Horn Type Focusing Element made with Separate Conductors

focusing, positron, secondary-beams, optics

1443

A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA

We describe the device for focusing of charged particles by the system of separated conductors which follow the parabolic profile. Basically this is a horn-type focuser, but with the individual conductors instead of continuous surface. This device allows substantial reduction of fabrication cost with the same focusing properties as the continuous parabolic surface. We recommend this “bird-cage” type system for focusing pions/muons in the projects under discussion in many Laboratories around the World.

TUPPR007

Beam Background and MDI Design for SuperKEKB/Belle-II

background, luminosity, neutron, radiation

1825

H. Nakayama, M. Iwasaki, K. Kanazawa, Y. Ohnishi, S. Tanaka, T. Tsuboyama
KEK, Tsukuba, Japan
H. Nakano
Tohoku University, Graduate School of Science, Sendai, Japan

The Belle experiment, operated at the asymmetric electron-positron collider KEKB, had accumulated a data sample with an integrated luminosity of more than 1 ab⁻¹ before the shutdown in June 2010. We have started upgrading both the accelerator and the detector, SuperKEKB and Belle-II, to achieve the target luminosity of 8×10³⁵ cm⁻² s⁻¹. With the increased luminosity, the beam background will be severe. The development of Machine- Detector Interface (MDI) design is crucial to cope with the increased background and protect Belle-II detector. We will present the estimation of impact from each beam background sources at SuperKEKB, such as Touschek-scattering, Beam-gas scattering, radiative Bhabha process, etc.. We will also present our countermeasures against them, such as collimators to stop scattered beam particles, Tungsten shield to protect inner detectors from shower particles, and dedicated beam pipe design around interaction point to stop synchrotron radiation, etc.

TUPPR020

Updates to the CLIC Post-collision Line

simulation, radiation, shielding, background

1855

L.C. Deacon
CERN, Geneva, Switzerland

The 1.5 TeV Compact Linear Collider (CLIC) beams, with a total power of 14 MW per beam, are disrupted at the interaction point due to the very strong beam-beam effect. The disrupted beam has a power of 10 MW. Some 3.5 MW reaches the main dump in the form of beamstrahlung photons, and about 0.5 MW of e⁺ and e^- coherent pair particles with a very broad energy spectrum as well as the lower energy disrupted beam particles need to be disposed of along the post collision line. Calculations for the energy deposition in the magnet coils and the resulting magnet lifetimes for various shielding configurations are presented.

TUPPR057

Intrabeam Scattering Studies at the Swiss Light Source

emittance, damping, storage-ring, monitoring

1951

F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
M. Aiba, M. Böge, N. Milas, A. Streun
Paul Scherrer Institut, Villigen, Switzerland
T. Demma
INFN/LNF, Frascati (Roma), Italy

The target parameters of modern ultra-low emittance rings are entering into a regime where intra-beam scattering (IBS) becomes important and, in the case of linear collider damping rings, even a limitation for the delivered emittances. The Swiss Light Source (SLS) storage ring, as it has achieved a vertical geometrical emittance of around 2 pm at 2.4 GeV, and it has the ability to run at even lower energies, and the availability of emittance monitoring diagnostics, is an ideal test bed for IBS studies. Simulations using the classical IBS theories and tracking codes are undertaken in order to explore the possibilities and limitations for IBS measurements at the SLS. In this respect, comparison between the theories and codes is first discussed. The dependence of the output emittances, taking into account the effect of IBS, with respect to energy, bunch charge and zero current vertical and longitudinal emittance is also studied, in order to define the regimes where the IBS effect can be significant. First measurement results from the SLS running at lower energies are finally presented.

WEPPD055

Gamma-rays Generation with 3D 4-mirror Cavity for ILC Polarized Positron Source

cavity, laser, photon, electron

2645

T. Akagi, S. Miyoshi
Hiroshima University, Graduate School of Advanced Sciences of Matter, Higashi-Hiroshima, Japan
S. Araki, Y. Funahashi, Y. Honda, T. Okugi, T. Omori, H. Shimizu, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
H. Kataoka, T. Kon
Seikei University, Japan
M. Kuriki, T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
K. Sakaue, M. Washio
RISE, Tokyo, Japan
R. Tanaka, H. Yoshitama
Hiroshima University, Higashi-Hiroshima, Japan

We are conducting gamma-rays generation experiment by the laser-Compton scattering using a Fabry-Perot cavity. We developed a 3D 4-mirror cavity, and it is installed at the KEK-ATF. By using a 3D 4-mirror cavity, small laser spot can be achieved with stable resonant condition. In addition, we aim 1900 times enhancement of input laser power by a 4-mirror cavity to increase the number of gamma-rays.

WEPPD062

Measurements of the First RF Prototype of the Spiral2 Single Bunch Selector

vacuum, impedance, high-voltage, simulation

2663

M. Di Giacomo
GANIL, Caen, France
A.C. Caruso, F. Consoli, G. Gallo, D. Rifuggiato, E. Zappalà
INFN/LNS, Catania, Italy
A. Longhitano
ALTEK, San Gregorio (CATANIA), Italy

Funding: Work supported by EU commission 7th framework project n. 212692.
The single bunch selector of the Spiral2 driver uses 100 Ω travelling wave electrodes driven by fast pulse generators. A 2.5 kV, 1 kW feed-through and a vacuum chamber housing the water cooled electrodes have been designed and built. The paper reviews the whole design and reports the results of first RF and power measurements.

WEPPD065

Development of a Laser-based Alignment System Utilizing Fresnel Zone Plates at the KEKB Injector Linac

laser, alignment, linac, focusing

2672

T. Suwada, M. Satoh
KEK, Ibaraki, Japan
K. Minoshima, S. Telada
AIST, Tsukuba, Japan

A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the 600-m-long KEKB injector linac. A well-known sequential three-point method with Fresnel zone plates and a CCD camera is revisited in the alignment system. The high-precision alignment system is strongly required in order to stably accelerate high-brightness electron and positron beams with high bunch charges and also to keep the beam stability with higher quality towards the Super B-factory at KEK. A new laser optics has been developed and the laser propagation characteristics has been systematically investigated at a 100-m-long straight section in vacuum. In this report, the experimental developments and investigations are reported along with the design of the new laser-based alignment system.

WEPPR015

Intrabeam Scattering Studies at CesrTA

emittance, electron, positron, lattice

2970

M. P. Ehrlichman
Cornell University, Ithaca, New York, USA
F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
W. Hartung, M.A. Palmer, D.P. Peterson, N.T. Rider, D. L. Rubin, J.P. Shanks, C.R. Strohman, S. Wang
CLASSE, Ithaca, New York, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: NSF Award (PHY-0734867) NSF Award (PHY-1002467) Japan/US Cooperation Program Education and lifelong learning, co-financed by Greece and the European Union
Intrabeam scattering dilutes the emittance of low energy, low emittance rings. Because CesrTA can be operated at low energies with low transverse emittances and high bunch intensity, it is an ideal laboratory for the study of IBS effects. Furthermore, CesrTA is instrumented for accurate beam size measurements in all three dimensions, providing the possibility of a complete determination of the intensity dependence of emittances. Models based on classical IBS theories and multi-particle simulations are used to estimate the effect of IBS at CesrTA at different beam emittances, intensities and energies. The first measurements from machine studies at CesrTA are presented.

WEPPR028

An Estimate of Out of Time Beam Upon Extraction for Mu2e

septum, extraction, proton, background

2994

N.J. Evans, S.E. Kopp
The University of Texas at Austin, Austin, Texas, USA
E. Prebys
Fermilab, Batavia, USA

Funding: U.S. Dept. of Energy.
A bunched beam with specific structure is crucial to attaining the experimental sensitivity desired by the Mu2e collaboration. The final goal is a ratio of in-time to out-of-time beam, known as beam extinction, of 10^-10. An AC dipole system is in development to attain the final goal by sweeping out-of-time beam onto a collimation system, but it is still necessary to achieve something on the order of 10^-5 when beam is extracted from the Fermilab Debuncher ring to the experiment hall. Several sources of out-of-time beam in the Debuncher ring are analyzed, including: intrabeam scattering, RF noise, beam-gas interaction and scattering off of the extraction septum. Estimates are given for each source as well as a final estimate of total out-of-time beam expected upon extraction.

WEPPR086

Computed Wake Field Effects from Measured Surface Roughness in the Walls of the Cornell ERL

wakefield, vacuum, undulator, impedance

3132

M.G. Billing, G.H. Hoffstaetter, C.E. Mayes, K.W. Smolenski, H.A. Williams
CLASSE, Ithaca, New York, USA

Funding: Work supported by the NSF ERL Phase 1B Cooperative Agreement (DMR-0807731)
Wake fields arise from the discontinuities in a smooth vacuum chamber and will cause energy spread in the passing bunch. In an energy recovery linac (ERL), the spent bunches are decelerated before they are dumped to reuse the beam’s energy for the acceleration of new bunches. While the energy spread accumulated from wakes before deceleration is small compared to the beam’s energy after full acceleration, it becomes more important relatively as the beam’s energy decreases.* Thus, in an ERL wake fields can produce very significant energy spread in the beam as it is decelerated to the energy of the beam dump. We report on calculations of wake fields due to the roughness of the surface of the vacuum chamber walls as it affects the Cornell ERL design. These calculations include the effects from the measured roughness for real vacuum chamber wall surfaces.
* M. Billing, “Effect of Wake Fields in an Energy Recovery Linac”, PAC’09, Vancouver, BC, Canada, 4-8 May 2009.

THPPD041

Evaluation and Implementation of High Performance Real-Time Signal Processing For Rayleigh Scattering Based Quench Detection for High Field Superconducting Magnets

solenoid, LabView, simulation, superconducting-magnet

3602

G. Flanagan, R.P. Johnson
Muons, Inc, Batavia, USA
W.K. Chan, J. Schwartz
North Carolina State University, Raleigh, North Carolina, USA
Q. Ruan, D. Schmidt, L. Wenzel, C. Wimmer
National Instruments, Austin, USA

Funding: Supported in part by SBIR Grant 4747 · 11SC06251
YBCO coated conductors are one of the primary options for generating the high magnetic fields needed for future high energy physics devices. Due to slow quench propagation, quench detection remains one of the primary limitations to YBCO magnets. Fiber optic sensing, based upon Rayleigh scattering, has the potential for quench detection with high spatial resolution. This paper discusses the potential of multicore CPU's and FPGA’s to accelerate the signal processing demands associated with Rayleigh scattering based quench detection systems in a real-time environment.

THPPP070

Comparison of the Residual Doses Before and After Resumption of User Operation in J-PARC RCS

injection, alignment, target, neutron

3901

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

J-PARC Facilities were damaged by East Japan Earthquake in March 2011, but All Facirities resumed a beam operation from December 2012. In this paper, we report and compare the beam loss distribution and the residual doses before and after resumption of user operation in J-PARC RCS.

THPPR032

A Split-Electrode for Clearing Scattered Electrons in the RHIC E-Lens

electron, proton, ion, solenoid

4038

X. Gu, W. Fischer, D.M. Gassner, K. Hamdi, J. Hock, Y. Luo, C. Montag, M. Okamura, A.I. Pikin, P. Thieberger
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.
We are designing two electron lenses that will be installed at RHIC IR10 to compensate for the head-on beam-beam effect. To clear accumulated scattered electrons from 100 GeV proton-electron head-on collisions in the e-lens, a clearing split electrode may be constructed. The feasibility of this proposed electrode was demonstrated via the CST Particle Studio and Opera program simulations. By splitting one of the drift tubes in the e-lens and applying ~ 380 V across the two parts, the scattered electrons can be cleared out within several hundred micro-seconds. At the same time we can restrict the unwanted shift of the primary electron-beam that already passed the 2-m interaction region in e-lens, to less than 15um.

THPPR042

Optimisation of an Inverse Compton Scattering Experiment with a Real Time Detection Scheme Based on a Radio Luminescent Screen and Comparison of the X-rays Beam Characteristics with Simulations

electron, photon, laser, emittance

4068

A.S. Chauchat, JP. Brasile
TCS, Colombes, France
A. Binet, V. Le Flanchec, J-P. Nègre
CEA/DAM/DIF, Arpajon, France
J.-M. Ortega
LCP/CLIO, Orsay, Cedex, France

To optimize the detection of an 11-keV X-Ray beam produced by Inverse Compton Scattering at the ELSA facility*, with a 17 MeV electron beam and a 532 nm laser, we demonstrate the use of a very sensitive detection scheme, based on a radio luminescent screen used in the spontaneous emission regime. It has proven to be very sensitive and very effective to detect 11-keV X-Rays while rejecting the overall ambient noise produced in a harder spectral range. It allowed us to optimize the electron-photon interaction probability by observing in real time the effect of both beams transport parameters. We could then compare simulation results with experimental measurements that appear to be in good agreement.
*A.S. Chauchat et al. Instrumentation developments for production and characterization of Inverse Compton Scattering X-rays and first results with a 17 MeV electron beam, NIMA, V.622, I.1, P.129-135

THPPR061

Optimisation Studies of Accelerator Driven Fertile to Fissile Conversion Rates in Thorium Fuel Cycle

proton, neutron, simulation, target

4112

C. Bungau, R.J. Barlow, R. Cywinski
University of Huddersfield, Huddersfield, United Kingdom

The need for proliferation-resistance, longer fuel cycles, higher burn up and improved waste form characteristics has led to a renewed worldwide interest in thorium-based fuels and fuel cycles. In this paper the GEANT4 Monte Carlo code has been used to simulate the Thorium-Uranium fuel cycle. The accelerator driven fertile to fissile conversion rates have been calculated for various geometries. Several new classes have been added by the authors to the GEANT4 simulation code, an extension which allows the state-of-the-art code to be used for the first time for nuclear reactor criticality calculations.

THPPR068

Laser Compton Scattering X-rays as a Tool for K-edge Densitometry

photon, laser, electron, radiation

4133

M. Titberidze, K. Chouffani
IAC, Pocatello, IDAHO, USA

There is a huge interest in bright and tunable X-ray sources. These sources can be used in various research fields, including medical, biological and industrial fields. Laser Compton Scattering (LCS) technique gives us possibility to generate tunable, quasi monochromatic and polarized X-ray beam. One of the applications of LCS is the detection and quantitative identification of special nuclear materials (SNM) using K-edge densitometry(KED)method. Our group was the first one who has used a quasi-monochromatic LCS source to carry out KED experiments. The experiments showed that LCS technique could be used for SNM detection and quantification.

THPPR075

The UK MEIS Facility : A New Future

ion, target, quadrupole, alignment

4151

R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom

The Medium Energy Ion Scattering facility at the Daresbury Laboratory, one of only ~10 such facilities in the world, has served the UK community since 1996. It provides a 50-400 keV ion beam and a very comprehensive experimental station where samples can be studied and the energies and angles of the recoil ions measured. It is now closing, but will be be relocated some 50 miles to the University of Huddersfield: it should be recommissioned and available to users in early 2012. We will report on progress, and on the facilities which will be available for users at the new site and under the new management.