scattering

Paper	Title	Other Keywords	Page
MOPLT010	Collimation of Heavy Ion Beams in LHC	ion, collimation, proton, heavy-ion	551
	H.-H. Braun, R.W. Assmann, A. Ferrari, J.-B. Jeanneret, J.M. Jowett CERN, Geneva I.A. Pshenichnov RAS/INR, Moscow
	The LHC collimation system is designed to cope with requirements of proton beams having 100 times higher beam power than the nominal LHC heavy ion beam. In spite of this, specific problems occur for ion collimation, due to different particle-collimator interaction mechanism for ions and protons. Ions are subject to hadronic fragmentation and electromagnetic dissociation, resulting in a non-negligible flux of secondary particles of small angle divergence and Z/A ratios slightly different from the primary beam. These particles are difficult to intercept by the collimation system and can produce significant heat-load in the superconducting magnets when they hit the magnet vacuum chamber. A computer program has been developed to obtain quantitative estimates of the magnitude and location of the particle losses. Hadronic fragmentation and electromagnetic dissociation of ions in the collimators were considered within the frameworks of abrasion-ablation and RELDIS models, respectively. Trajectories of the secondary particles in the ring magnet lattice and the distribution of intercept points of these trajectories with the vacuum chamber are computed. Results are given for the present collimation system design and potential improvements are discussed.
MOPLT021	Attenuation and Emittance Growth of 450 GeV and 7 TeV Proton Beams in Low-Z Absorber Elements	proton, emittance, injection, simulation	581
	V. Kain, B. Goddard, Y. Kadi, R. Schmidt CERN, Geneva
	The intensity of the LHC beams will be several orders of magnitude above the damage thresholds for equipment, at 7 TeV, but also already at injection energy of 450 GeV. Passive protection of the equipment against failures during beam transfer, injection and dumping of the beam with absorbers and collimators is foreseen to ensure safe operation. Since these protection devices must be robust in case of beam impact, low-Z materials such as graphite are favored. The reduction of the energy density of the primary beam by the absorber is determined by the attenuation of the beam due to nuclear collisions and the emittance growth of the surviving protons due to scattering processes. Absorbers with low density materials tend to be several meters long to ensure sufficient reduction of the transverse energy density of the impacting beam. The physics principles leading to attenuation and emittance growth for a hadron beam traversing matter are summarised, and FLUKA simulation results for 450 GeV and 7TeV proton beams on low-Z absorbers are compared with theoretical predictions. Design criteria for the LHC absorbers can be derived from these results. As an example, for the transfer line from SPS to LHC a short, low-Z absorber has been proposed to protect the LHC injection elements.
MOPLT033	Experimental Studies of Controlled Longitudinal Emittance Blow-up in the SPS as LHC Injector and LHC Test-Bed	emittance, synchrotron, pick-up, beam-losses	617
	J. Tuckmantel, T. Bohl, T.P.R. Linnecar, E.N. Shaposhnikova CERN, Geneva
	The longitudinal emittance of the LHC beam must be increased in a controlled way both in the SPS and the LHC itself. In the first case a small increase is sufficient to help prevent coupled bunch instabilities but in the second a factor three is required to also reduce intra-beam scattering effects. This has been achieved in the SPS by exciting the beam at the synchrotron frequency through the phase loop of the main RF system using bandwidth-limited noise, a method that is particularly suitable for the LHC which will have only one RF system. We describe the tests that have been done in the SPS both for low and high intensity beams, the hardware used and the influence of parameters such as time of excitation, bandwidth, frequency and amplitude on the resulting blow-up. After taking into account intensity effects it was possible to achieve a controlled emittance increase by a factor of about 2.5 without particle loss or the creation of visible tails in the distribution.
MOPLT049	A Very High-beta Optics to be used for an Absolute Luminosity Determination with Forward Detectors in ATLAS	optics, luminosity, injection, emittance	659
	A. Faus-Golfe IFIC, Valencia I. Efthymiopoulos, P. Grafstrom, M. Rijssenbeek CERN, Geneva M. Haguenauer Ecole Polytechnique, Palaiseau
	Atlas detector at the LHC pursues a number of different approaches to obtain an estimate of the absolute luminosity. Measuring elastic scattering at very small angles (3 mu rad) represents a different and complimentary approach that will improve the precision of the final luminosity estimate. In this paper we show the required very hihg-beta optics, detector acceptance studies, and running conditions and calculated performance for the proposed forward detectors located near the ATLAS interaction region.
MOPLT050	High-beta and Very High-beta Optics for LHC	optics, insertion, quadrupole, power-supply	662
	A. Faus-Golfe IFIC, Valencia A. Verdier CERN, Geneva
	New high-beta and very high-beta optics has been sought in order to find the best possible configuration for measuring total cross section in TOTEM and absolute luminosity in ATLAS. They are based on nominal powering scheme of the low-beta triplet. A list of the various possible solution is given in this report. A particularly interesting solution has been found for a case where the phase advance in both planes at the detector location are close to pi/2.
MOPLT106	MICE: the Muon Ionisation Cooling Experiment	emittance, factory, background, instrumentation	782
	M. Ellis Imperial College of Science and Technology, Department of Physics, London
	The provision of intense stored muon beams would allow the properties of neutrinos to be measured precisely and provide a route to multi-TeV lepton-anti-lepton collisions. The short muon-lifetime makes it impossible to employ traditional cooling techniques while maintaining the muon-beam intensity. Ionisation cooling, a process in which the muon beam is passed through a series of liquid hydrogen absorbers followed by accelerating RF-cavities, is the proposed cooling technique. The international Muon Ionisation Cooling Experiment (MICE) collaboration proposes to perform an engineering demonstration of ionisation cooling. The MICE cooling channel, the instrumentation and the implementation at the Rutherford Appleton Laboratory is described together with the predicted performance of the channel and the measurements that will be made.
TUPLT069	Approaching to a Mono-modal Accelerating Cavity based on Photonic Band-gap Concepts	simulation, coupling, lattice, radiation	1309
	M.R. Masullo INFN-Napoli, Napoli A. Andreone, E. Di Gennaro, G. Lamura Naples University Federico II, Napoli F. Francomacaro, M. Panniello, V.G. Vaccaro Naples University Federico II and INFN, Napoli G. Keppel, V. Palmieri, D. Tonini INFN/LNL, Legnaro, Padova
	One of the main problem of high intensity accelerators is the presence of high order modes (HOMs) which might degrade the beam quality. Accelerating cavities require HOMs suppression while keeping high quality factor (Q) fundamental mode. Both these requirements can be hardly met in closed metallic cavities. In low frequency cases and for particular geometries it is possible to partially suppress HOMs, but at high frequencies and for superconducting cavities configuration becomes cumbersome and technically unviable. We propose here a high Q cavity based on Photonic Band Gap (PBG) concepts, operating in the microwave region. The cavity consists of a two-dimensional lattice, where posts (dielectric, metallic or superconducting) are sandwiched by two conducting plates. This sandwich exhibits two kinds of frequency bands: 'pass-bands' and 'stop-bands'. It is possible to localize modes in an equivalent cavity obtained by removing posts. These modes are localized in the 'cavity'. In this way, one can obtain a quasi-mono-modal cavity: high Q fundamental mode and HOMs falling into the pass bands. We will present the study, the optimisation and the measurements of our metallic (Copper) PBG structure working in the 2-20 GHz range. The development of a different cryogenic set-up, necessary to characterise an all superconducting or an hybrid (dielectric/metallic) structure, is under way.
TUPLT089	Status of PEFP 3MeV RFQ Development	rfq, proton, klystron, vacuum	1363
	Y.-S. Cho, B.-H. Choi, S.-H. Han, J.-H. Jang, Y.H. Kim, H.-J. Kwon, C.-B. Shim KAERI, Daejon
	In the PEFP (Proton Engineering Frontier Project), a 350MHz, 3MeV RFQ (Radio Frequency Quadrupole) has been developed and tested. The tuning results showed that the resonant frequency is somewhat higher than 350MHz and other methods in addition to slug tuners should be used to tune the cavity correctly. To check the cavity characteristics, high power RF test has been done. The required peak RF power is 600kW and pulse width, repetition rate for initial test are 100 micro-s, 10Hz respectively. To solve the problems in PEFP RFQ, the upgrade design of 3MeV RFQ has been decided. The main concept of this upgrade design is constant vane voltage profile with the same length of RFQ. The other parameters (350MHz, 3MeV, 20mA) are the same with the previous RFQ. With constant vane voltage profile, fabrication of RFQ can be easier, and with the same mechanical dimension, other parts such as vacuum pumping station can be re-used. In this paper, the test results of the PEFP RFQ, and the details of beam dynamics design/engineering design of upgrade RFQ will be presented.
TUPLT128	The Operation Modes of Kharkov X-ray Generator based on Compton Scattering NESTOR	electron, laser, photon, storage-ring	1428
	A.Y. Zelinsky, E.V. Bulyak, P. Gladkikh, I.M. Karnaukhov, A. Mytsykov, A.A. Shcherbakov NSC/KIPT, Kharkov T.R. Tatchyn SLAC/SSRL, Menlo Park, California
	The results of theoretical and numerical considerations of linear Compton scattering are used to evaluate characteristics of X-rays produced by collision between a low emittance electron beam and intensive laser light in an X-rays generator NESTOR of NSC KIPT. Two main generation modes have been under consideration at preliminary NESTOR design. There are the operation mode for medicine 33.4 keV X-rays production using 43 Mev electron beam and Nd:YAG laser beam and higher energy X-rays production mode providing X-rays with energy up to 900 keV with 225 MeV electron beam and Nd:YAG laser beam. It is supposed to use an optical cavity for laser beam accumulation of about 2.6 m long and an interaction angle of about 30 in both operation modes. A few more operation modes provide possibility to expand operation range of NESTOR. Using interaction angle 100 and 1500 along with optical resonator 42 or 21 cm long and the second mode of laser light it is possible to produce X-rays in energy range from a few keV till 1.5 MeV. The intensity and spectral brightness of the X-rays is expected to be ~ 1013 phot/s and ~ 1013 phot/s/mm2/mrad2/0.01%BW respectively.
WEPKF007	Vacuum Characterisation of a Woven Carbon Fiber Cryosorber in Presence of H2	vacuum, electron, injection, collider	1603
	V. Baglin, H. Dupont, T. Garcin CERN, Geneva
	Some of the cryogenic components in the Large Hadron Collider (LHC) will operate at 4.5 K. The H2 desorption will rapidly increase to the saturated vapour pressure, 3 orders of magnitude larger than the design pressure. Therefore, the use of cryosorbers is mandatory to provide the required pumping capacity and pumping speed. The behaviour of a woven carbon fiber to be used as a cryosorber has been studied under H2 injection. The pumping speed and capacity measured in the range 6 to 30 K are described. Observations made with an electron microscope are shown. A proposed pumping mechanism and the implications to the LHC are discussed.
WEPLT013	Investigation of Space Charge Effects and Intrabeam Scattering for Lead Ions in the SPS	space-charge, injection, proton, emittance	1846
	H. Burkhardt, D. Manglunki, M. Martini, F. Roncarolo CERN, Geneva G. Rumolo GSI, Darmstadt
	Space charge effects and intrabeam scattering usually play a minor role in high energy machines like the SPS. They can potentially become a limitation for the heavy ion beams needed for the LHC at the injection plateau in the SPS. Experimental studies on space charge limitations performed on low energy proton beams in the SPS will be described. Theoretical studies have been performed to predict emittance growth times due to intrabeam scattering using several different codes.
WEPLT140	New Abilities of Computer Code DeCA	photon, electron, simulation, laser	2164
	P. Gladkikh, A.Y. Zelinsky NSC/KIPT, Kharkov
	In the paper the status and new abilities of computer code package DeCA (Design of Cyclic Acclerators) are described. The main effort of the code developers were made to creation of software capable to simulate intrabeam scattering effect and Compton scattering. In addition modules for calculation of the second order dispersion and momentum compaction factor were developed.
THOBLH02	Ultrafast Compton Scattering X-Ray Source Development at LLNL	electron, laser, photon, interaction-region	270
	F.V. Hartemann, S. Anderson, C.P.J. Barty, S.M. Betts, R. Booth, J. Brown, K. Crane, R.R. Cross, D.N. Fittinghoff, D. Gibson, E.P. Hartouni, J. Kuba, G.P. Le Sage, D.R. Slaughter, P.T. Springer, A. Tremaine, A.J. Wootton LLNL, Livermore, California J. Rosenzweig UCLA, Los Angeles, California
	The LLNL PLEIADES (Picosecond Laser-Electron Inter-Action for the Dynamical Evaluation of Structures) facility is now operating between 30 and 80 keV, and produces > 5 x 106 photons per shot at 10 Hz. This important milestone offers a new opportunity to develop laser-driven, compact, tunable x-ray sources for critical applications such as NIF diagnostics, time-resolved material studies, and advanced biomedical imaging. Initial x-rays were captured with a CCD using a CsI scintillator; the photon energy was measured at approximately 70 keV, and the observed spectral and angular distributions found to agree very well with three-dimensional codes. The electron beam was focused to 30 um rms, at 54 MeV, with 250 pC of charge, a relative energy spread of 0.2%, and a normalized emittance of 10 mm.mrad. Optimization of the x-ray dose is currently underway, with the goal of reaching 107 photons per shot and a peak brightness approaching 1017 photons/mm2/mrad2/s/0.1%bandwidth. High-Z K-edge radiographs have been demonstrated, as well as diffraction using highly-ordered pyrolytic graphite crystals. Nonlinear scattering experiments, using a tightly focused laser spot will also be discussed, as well as plans to develop a source capable of reaching 1% conversion efficiency from the electron beam kinetic energy into x-rays, and ultrafast diffraction experiments.
	Video of talk
	Transparencies
THPKF001	Status of 3 GeV CANDLE Synchrotron Light Facility Project	brightness, photon, synchrotron, emittance	2254
	V.M. Tsakanov, M. Aghasyan, G. Amatuni, V.S. Avagyan, A. Grigoryan, B. Grigoryan, M. Ivanyan, V. Jalalyan, D.K. Kalantaryan, V.G. Khachatryan, E.M. Laziev, Y.L. Martirosyan, R.H. Mikaelyan, S. Minasyan, K.N. Sanosyan, S. Tatikian, S. Tunyan, A. Vardanyan CANDLE, Yerevan
	CANDLE- Center for the Advancement of Natural Discoveries using Light Emission – is a 3 GeV third generation synchrotron light facility project in Republic of Armenia. The presentation includes the main considerations that underlie the Conceptual Design Report of the project and the progress made after the last EPAC conference. An overview of machine and beam physics study, the prototype and laboratory development is given.
THPKF006	Lifetime Studies in the LNLS Electron Storage Ring	storage-ring, synchrotron, coupling, single-bunch	2266
	N.P. Abreu, P.F. Tavares LNLS, Campinas
	In this paper we present a set of measurements performed at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. We measured the beam lifetime as a function of: current per bunch, gap voltage and position of horizontal and vertical scrapers. Those measurements helped us to determine the contribution of various particle loss mechanisms (Touschek, elastic and inelastic scattering and quantum fluctuations) to the lifetime of the beam. Comparison with theory is also presented as well as an interpretation of each effect.
THPKF063	Parameters of X-ray Radiation Emitted by Compton Sources	electron, laser, collimation, photon	2409
	E.V. Bulyak, V. Skomorokhov NSC/KIPT, Kharkov
	Presented are results of analytical study on X–ray beam parameters generated in the Compton storage rings. A model with the given circulating electron bunch parameters and the laser splash as well is considered. For this model, the total yield of x–ray quanta is derived as a function of the crossing angle and geometric dimensions of both the bunch and splash. Also spectral characteristics of emitting x–ray beam are evaluated with account for the collimating conditions and both the angular and energy spreads in the bunch. As is shown the width of x–ray energy spectrum is narrowest for the x-ray beam collimated along the bunch orbit. With increasing the scattering angle (with respect to the bunch orbit) the spectrum of emitting quanta is widening. Problems of x-ray beam generation with required energy and brightness with the Compton storage rings are discussed.
THPLT031	Comparison of Rate Equation Models for Equilibrium Beam Parameters	electron, target, antiproton, storage-ring	2544
	R.W. Hasse, O. Boine-Frankenheim GSI, Darmstadt
	We calculate equilibrium beam parameters from the counteraction of intrabeam scattering (IBS), electron cooling (EC) and target interaction for typical beams in the GSI cooler storge ring ESR and in the proposed HESR. This work is complementary to kinetic modeling efforts at GSI. We developed an easy to use simulation tool that includes various models for the EC rates and the IBS rates, averaged of the detailed ring lattices. The obtained scaling of the equilibrium parameters with beam current and energy are compared with existing experimental data from the ESR and with kinetic simulation results for the HESR.
THPLT045	A more Accurate Approach to Calculating Proton Bunch Evolution under Influence of Intra-beam Scattering in a Storage Ring.	proton, synchrotron, storage-ring, background	2583
	I.V. Agapov, F.J. Willeke DESY, Hamburg
	Some perturbations of discrete nature are known to influence the performance of a proton storage ring, contributing to parasitic background, decay of beam currents and bunch tail buildup. Such are, for example, intra-beam scattering and residual gas scattering .These processes are to a big extent described by existing analytical theory. The latter, employing a large amount of averaging, usually neglects effects arising from system nonlinearity. So, the motion of tail particles in the presence of a sufficiently nonlinear RF voltage under influence of intra-beam scattering strongly deviates from the average across the bunch and the analytical approach seems inadequate for it. To overcome this situation we have developed more accurate numerical methods for calculations of bunch evolution under influence of a rather broad class of jump-like perturbations. Here we present the computational algorithms and their application to assessment of coasting beam and proton background in HERA-p.
THPLT064	Enhancement of Laser Power from a Mode Lock Laser with an Optical Cavity	laser, resonance, electron, target	2637
	M. Nomura, K. Hirano, M. Takano NIRS, Chiba-shi S. Araki, Y. Higashi, T. Taniguchi, J. Urakawa, Y. Yamazaki KEK, Ibaraki Y. Honda, N. Sasao, K. Takezawa Kyoto University, Kyoto H. Sakai ISSP/SRL, Chiba
	We have developed a laser-wire beam monitor to measure a beam profile in the KEK/ATF damping ring. This monitor is based on the inverse Compton scattering with a thin wire of the laser. The laser-wire is produced with a Fabry-Perot optical cavity in which laser power from a CW laser is stored and enhanced up to 1000 times. We have a plan to increase a gamma ray flux by using a pulsed laser instead of the CW laser. There are many applications for such a high flux gamma ray, e.g. medical use, transmutation and so on. We have done a test experiment of laser pulse stacking with a mode lock laser where wavelength is 1064 nm, repetition rate 357MHz, pulse width 7psec(FWHM) and a 42 cm long Fabry-Perot optical cavity. The experimental results show that laser power in the optical cavity can be enhanced by laser pulse stacking.
THPLT070	Design and Constriction of Coronagraph for Observation of Beam Halo	factory, photon, background, optics	2655
	T. Mitsuhashi KEK, Ibaraki
	The coronagraph is a spatial telescope to observe the sun-corona by artificial eclipse. The concept of this apparatus is to realize the Schlieren-optical system for cutting the bright diffraction fringes in order to observe a less-bright object surrounding the main image such as the sun-corona. We applied this concept for the observation of the surrounding structure (halo, tail) of the beam. Since the background is mainly scattered light come from the objective lens, the key point to observe a less-intense object is to reduce scattering light from objective lens. We used a very well-polished lens (better than scratch and dig 20/20) as objective lens, and succeeded to obtain the signal to background ratio better than 10-5. As a test, we tried to observe the tail of beam by hiding the central peak with artificial eclipse by the coronagraph at Photon Factory storage ring. We succeeded to observe the tail of beam which has an intensity range of 1/104 of the peak intensity.
THPLT077	MPI Parallel Computation of Wake Fields by Using Time Domain Boundary Element Method	simulation, electromagnetic-fields	2673
	K. Fujita, H. Kawaguchi Muroran Institute of Technology, Department of Electrical and Electronic Engineering, Muroran T. Weiland, I. Zagorodnov TEMF, Darmstadt
	This paper presents wake field and wake potential calculation by using the Time Domain Boundary Element Method (TDBEM) on the MPI parallel computation system. The TDBEM is based on the electric field integral equation (EFIE) and the electric field integral equation (MFIE) in time domain. In wake field simulation, an important advantage of these equations is that electromagnetic fields in an accelerator cavity are explicitly expressed as a sum of charged particle self-fields and wake fields in time domain. On the other hand, the TDBEM has serious difficulties in practical numerical simulation, such as numerical instabilities, huge memory requirements, and heavy calculation cost. However, recent remarkable progress of computer performance makes the TDBEM possible to be used in practical simulations. According to these backgrounds, we apply the TDBEM to wake field simulation in the MPI parallel computer system. Simulation results are compared with that of a conventional method, the Finite Integration Techniques (FIT), and good agreements are shown.
THPLT081	Present Status of Photo-cathode RF Gun System and its Applications at Waseda University	laser, electron, gun, emittance	2685
	R. Kuroda, Y. Hama, K. Hidume, H. Hirama, M. Kawaguchi, N. Kudo, T. Kuribayasi, S. Minamiguchi, R. Moriyama, T. Saito, K. Sakaue, D. Ueyama, M. Washio RISE, Tokyo H. Hayano, J. Urakawa KEK, Ibaraki S. Kashiwagi ISIR, Osaka X.J. Wang BNL/NSLS, Upton, Long Island, New York
	High quality electron beam generation using photo-cathode rf gun system and its application have been developed at Waseda University. This system can generate about 4 MeV low emittance electron beam. This is applied for soft X-ray generation using laser Compton scattering and pulse radiolysis experiments based on the pump-probe technique. In case of the soft X-ray generation, Compton scattering experiments between about 4.2 MeV electron beam and Nd:YLF laser light (1047nm) is performed at 20 degrees interaction angle, so that about 300 eV soft X-ray is generated. In case of the pulse radiolysis experiments, the electron beam is used for the pump beam. The probe light is generated as white light by concentrating Nd:YLF laser light (1047nm) on the water cell. The measurement with about 30 ps (FWHM) time resolution of this system is demonstrated for the absorption of hydrated electrons. In this conference, we will present the experimental results, status of this system and future applications.
THPLT094	Ordered Ion Beam in Storage Rings	ion, simulation, storage-ring, emittance	2715
	A. Smirnov, I.N. Meshkov, A.O. Sidorin, E. Syresin, G.V. Troubnikov JINR, Dubna, Moscow Region T. Katayama CNS, Saitama H. Tsutsui SHI, Tokyo
	The using of crystalline ion beams can increase of the luminosity in the collider and in experiments with targets for investigation of rare radioactive isotopes. The ordered state of circulating ion beams was observed experimentally at several storage rings. In this report a new criteria of the beam orderliness are derived and verified with BETACOOL code with using molecular dynamics technique. The sudden reduction of momentum spread observed on a few rings is described with this code. The simulation shows a good agreement with the experimental results. The code has then been used to calculate characteristics of the ordered state of ion beams for ion rings which will have experimental programs for the study of crystalline beams. A new strategy of the cooling process is proposed which permits to increase the linear density of the ordered ion beam.
THPLT099	The Analysis of the Electron Beam Scanning Method for the Beam Profile Monitoring.	electron, ion, injection, space-charge	2721
	D.A. Liakin ITEP, Moscow
	The method of the beam profile monitoring with scanning electron beam is analyzed. Simulation model of the ion/electron beam interaction is presented and some simulation results are shown. In the report the estimation of overall performance characteristics of this method such as sensitivity, spatial resolution, frequency bandwidth etc. are given.
THPLT106	Measurement of Beam Polarization in VEPP-3 Storage Ring using Internal Target-based Moeller Polarimeter	polarization, target, electron, background	2730
	A.V. Grigoriev, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.I. Mishnev, S.A. Nikitin, D.M. Nikolenko, I.A. Rachek, Y.V. Shestakov, D.K. Toporkov, V.N. Zhilich BINP SB RAS, Novosibirsk
	A method for beam polarization measurement in a storage ring has been for the first time developed and applied based on measuring the asymmetry in scattering of polarized beam electrons on the internal polarized gas jet target. Using this method we have studied the polarization in VEPP-3 booster storage ring. VEPP-3 is the source of polarized beams for VEPP-4M electron-positron collider in the planned experiment on high-precision mass measurement of tau-lepton near the production threshold of the latter (1777 MeV). Radiative polarization of beams obtained in VEPP-3 is used for absolute calibration of particle energy by the resonant depolarization technique after injection into VEPP-4M ring. The polarimeter design is described. Results of polarization measurements performed in 60 MeV range of VEPP-3 energy contiguous from above to tau-lepton production threshold are presented and discussed. The depolarizing influence of the integer machine spin resonance (1763 MeV) as well as of the combination spin resonances with the betatron frequencies are found to be significant.
THPLT108	The Study of the Beam TAILS with the Optical Coronagraph	vacuum, simulation, storage-ring, collider	2736
	O.I. Meshkov, M.G. Fedotov, E.V. Kremyanskaya, E. Levichev, N.Y. Muchnoi, Yu.A. Pakhotin, N.A. Selivanov, A.N. Zhuravlev BINP SB RAS, Novosibirsk
	Optical white-light Lyot coronograph is applied at the VEPP-4M collider to study the "tails" of the transverse beam profile. The device is used for investigation of the beam-beam effects.
THPLT122	The Energy Deposition Profile of 0.1-3.0 MeV Electrons in NaCl	electron, target, positron, radiation	2756
	V.V. Gann NSC/KIPT, Kharkov A.V. Sugonyako, D.I. Vainshtein, H.W. den Hartog RUG, Groningen
	An analysis is presented of existing experimental and theoretical data of energy loss profiles and energy deposition in thick targets irradiated with MeV-energy electrons. A simple approximate calculation is proposed for the energy deposition profile of a perpendicular beam of 0.1-3 MeV electrons in matter. The results obtained with this method are in agreement with existing calculated and measured energy absorption profiles for a variety of materials. It will be shown that the build-up phenomenon has a significant effect on the energy deposition profile in thick samples. A systematic experimental investigation of the energy deposition profile of 0.5 MeV electrons in 0.2 - 0.8 mm thick NaCl platelets has been carried out. The distribution of the absorbed dose was determined with differential scanning calorimetry method by measuring either the latent heat of melting of the radiation-induced Na-precipitates or the stored energy.
THPLT171	Stochastic Cooling Studies in RHIC, II	kicker, pick-up, feedback, proton	2861
	M. Blaskiewicz, J.M. Brennan, J. Wei BNL, Upton, Long Island, New York
	Intra-beam scattering is unavoidable for highly charged heavy ions and causes emittance growth during the store for collision physics. A longitudinal bunched beam stochastic cooling system will confine the bunch within the RF bucket increasing the useful luminosity. A single bunch, Palmer cooling system is under investigation. We present data and compare them with theory.