• M. Turenne, R.P. Johnson
  Muons, Inc, Batavia
• F. Hunte, J. Schwartz
  NHMFL, Tallahassee, Florida

Funding: Supported in part by DOE SBIR grant DE-FG02-08ER85024

Optical fibers can be imbedded within new high temperature superconductor (HTS) magnets to monitor strain and temperature, to detect quenches, and, in the case of AgX/Ag/Bi2Sr2CaCu2Ox, (Bi2212) wire magnets, to serve as a heat treatment process monitor for wind-and-react (W&R) manufacturing. The W&R process requires that the optical fibers be installed before the Bi2212 heat treatment, one important issue is whether the fibers survive the 890 oC heat treatment so as to monitor the heat treatment and to serve subsequently as a low temperature monitor. Here, Au-coated optical fibers are attached to Bi2212 wires and processed with the typical reaction cycle. The Bi2212 superconductor is then evaluated for performance degradation due to the presence of the fiber and the fiber is evaluated for performance degradation due to the heat treatment and viability as a heat treatment process monitor. Two approaches to fiber optic sensing are used: a fiber Bragg grating and Rayleigh scattering

• K. L. Jensen, J.L. Shaw, J.E. Yater
  NRL, Washington, DC
• D.W. Feldman, E.J. Montgomery, P.G. O'Shea, P.Z. Pan
  UMD, College Park, Maryland
• N.A. Moody
  LANL, Los Alamos, New Mexico
• J.J. Petillo
  SAIC, Burlington, Massachusetts

Funding: We gratefully acknowledge funding provided by the Joint Technology Office and the Office of Naval Research

Laser switched photocathodes are now the electron source of choice for short wavelength Free Electron Lasers. The photocathode requirements are profound: ideally, capabilities such as high peak and average current, high quantum efficiency (QE) in the visible, long lifetime in an rf injector and the ability to be repaired in situ are desired. We are pursuing cathodes with self-rejuvenating surfaces based on cesium dispenser cathode technology*,**, in which the physics of recesiation, evaporation, diffusion, and evolution of the surface coating and the QE are the metrics of performance. Here, we present predictive theoretical models of surface evolution and QE in a manner appropriate for inclusion in beam simulation codes, wherein emission non-uniformity and dark current affect emittance, beam halo, and dynamic evolution of bunched electron beams***. The emission models focus on bulk transport issues (including scattering processes) and surface conditions (including diffusion in the presence of random, non-uniform sub-monolayer coverage), and relate these factors to recent experimental characterizations of the surface evolution.

*Jensen, et al., JAP{10}2, 074902 ; Moody, et al., APL90, 114108.
**E. Montgomery, et al., (this conference)
***Petillo, et al., Proc IEEE PAC (2007); Jensen, et al., PRST-AB 11, 081001.

• M. Uesaka
  The University of Tokyo, Nuclear Professional School, Ibaraki-ken
• R. Kuroda, K. Yamada
  AIST, Tsukuba, Ibaraki
• K. Mizuno, A. Mori, T. Natsui, H. Taguchi, J.D. Trono
  University of Tokyo, Tokyo
• N. Yusa
  Tohoku University, Graduate School of Engineering, Sendai

In X-ray Drug Delivery System, anticancer drugs containing Pt, such as cisplatin and dachplatin, and Au colloid contrast agent are surrounded by polymers (micelle, PEG (polyethylene glycol), etc.).Ttheir sizes are controlled to be 20-100 nm. Since holes of capillary to organ are as large as 100 nm in only cancer, those large particles can be accumulated in cancer effectively. That is called as EPR (Extended Penetration and Retention effect). We have observed the distribution of Pt of dachplatin-micelle in cancer of mouse’s pancreas by X-ray fluorescence analysis using 10 μm pinpoint 15 keV X-ray by SPring8. Further, in-vitro- and in-vivo-experiments of Au colloid PEG are under way. It is expected to be used as contrast agent for dynamic tracking treatment for moving cancer. Imaging properties for polychromatic X-rays from X-ray tube and monochromatic Compton source are numerically analyzed and discussed. We continue to analyze radiation enhancement by Auger electrons and successive characteristic X-rays and its toxic effect to cancer.

• C. Bungau
  Manchester University, Manchester
• R.J. Barlow
  UMAN, Manchester
• A. Bungau, R. Cywinski
  University of Huddersfield, Huddersfield

Nuclear power production can benefit from the development of more comprehensive alternatives for dealing with long-term radioactive waste. One such alternative is an accelerator-driven subcritical reactor (ADSR) which has been proposed for both energy production and for burning radioactive waste. Here we investigate the effects of the size of the ADSR spallation target on the total neutron yield integrated over the neutron energy and emission angle. The contribution to the total neutron yield from the (n, xn) neutron interactions is evaluated at proton beam energies between 0.4 and 2 GeV. Calculations have been carried out with the GEANT4 simulation code using the Liege intranuclear cascade model and the results are compared to the the LAHET/MCNP code package predictions.

• C. Sun, Y.K. Wu
  FEL/Duke University, Durham, North Carolina
• G. Rusev, A. Tonchev
  TUNL, Durham, North Carolina

A gamma-ray beam produced by Compton scattering of a laser beam with a relativistic electron beam has been used to determine the electron beam parameters. In the past, the electron beam energy and energy spread were directly fit from the high energy edge of a measured gamma beam spectrum using a gamma-ray detector. However, due to non-ideal response of the detector, the measured spectrum cannot represent the true energy distribution of the gamma-ray beam. Thus, the electron beam energy and energy spread could not be accurately determined from the measured gamma beam spectrum. In this paper, we will present a novel end-to-end spectrum reconstruction method to accurately extract the energy distribution of the gamma-ray beam from the measured gamma beam spectrum. Using this method we have accurately determined the energy and energy spread of the electron beam in Duke storage ring using a Compton gamma-ray beam from the High Intensity γ-ray Source (HIγS) facility.

• L. Auditore
  INFN - Gruppo Messina, S. Agata, Messina
• L. Auditore, R.C. Barnà, D. Loria, E. Morgana, A. Trifirò, M. Trimarchi
  Università di Messina, Messina
• M. Carpinelli
  INFN-Cagliari, Monserrato (Cagliari)
• A. Franconieri, M. Gambaccini
  INFN-Ferrara, Ferrara

At the Dipartimento di Fisica, Università di Messina, an X-ray source based on a 5 MeV electron linac has been designed. By means of the MCNP-4C2 code, several simulations have been performed to evaluate if the source can be used as a NDT device for material recognition purposes. In particular, being able to vary the electron beam energy for producing bremsstrahlung beams with different absorption, X-ray transmission through several materials and for different X-ray beams energy has been studied. First results have shown the capability of the system to distinguish dissimilar materials by properly choosing the X-ray beam end-point energy and processing the obtained transmission values. Since the uncertainties level in the material identification could be improved differentiating the response of the imaging system, a theoretical study has been performed to evaluate how X-ray beams obtained with different end-point energies, and eventually transmitted by properly chosen filters, are absorbed by different scintillators. The obtained results will be presented and discussed in order to give indications on the real chance to use the designed device for material recognition purposes.

• M. Kinsho
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

The J-PARC 3-GeV rapid cycling synchrotron (RCS) has been beam commissioned since October 2007 and it has been able to provide downstream facilities, the 50-GeV synchrotron (MR) and the Materials and Life Science Facility (MLF) with stable beam required from them. After beam deliver operation to the MR and MLF, while the priority ha s been given to their beam tuning, the RCS also continues further beam studies toward higher beam intensity. On September 18th, 2008, the RCS achieved the beam power of 210kW to beam dump with 25Hz. This presentation will concentrate itself on the outcome of the J-PARC RCS commissioning program, including the discussion on the issues of the high-power operation.

• P.K. Saha, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• Y. Irie
  KEK, Ibaraki
• T. Toyama
  J-PARC, KEK & JAEA, Ibaraki-ken

The beam loss issues connected to the nuclear scattering together with the multiple Coulomb scattering at the charge-exchange foil during the multi-turn injection has been studied in detail for the RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex). Recently, during the beam commissioning of RCS, some experimental data related to such issue has been taken and thus a comparison of the measured beam loss to the estimated one is reported in this paper. When the beam loss from such a source is unavoidable, a realistic estimation is quite important for a fair design of the injection system and the vicinity in order to reduce especially, the uncontrolled beam loss.

• W.J.M. Weterings, M. Aiba, J. Borburgh, C. Carli, T. Fowler, B. Goddard
  CERN, Geneva

For the LINAC4 project the PS Booster (PSB) injection system will be upgraded. The 160 MeV H^- beam will be distributed to the 4 superimposed PSB synchrotron rings and horizontally injected by means of an H^- charge-exchange system. Operational considerations for the injection system are presented, including expected beam losses from field stripping of H^- and excited H0 and foil scattering, possible injection failure cases and expected stripping foil lifetimes. Loading assumptions for the internal beam dumps are discussed together with estimates of doses on various components.

• F. Broggi
  INFN/LASA, Segrate (MI)
• A. Bacci, A.R. Rossi, L. Serafini
  Istituto Nazionale di Fisica Nucleare, Milano
• A. Cianchi
  INFN-Roma II, Roma
• A. Clozza, G. Di Pirro
  INFN/LNF, Frascati (Roma)

High vacuum has always been mandatory in particle accelerator. This is true especially for circular machine, where the beam make thousands or millions turns, and beam lifetime is heavily affected by the residual gas scattering. In dimensioning the interaction chamber for a plasma accelerator experiment, because of gas needed and the diagnostics and control devices foreseen, the problem of the effect of the residual gas on the beam arose. Simulation of the beam interaction with the residual gas in the chamber has been performed with FLUKA code. The effects of different vacuum levels on the electron beam is reported and consequences on the beam quality in linacs is discussed.

• D.J. Gibson, S.G. Anderson, C.P.J. Barty, S.M. Betts, F.V. Hartemann, M. J. Messerly, H.H. Phan, M. Shverdin, C. Siders
  LLNL, Livermore, California

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Recently, a drive laser for an 2.86 GHz rf photoinjector, designed to provide a pulse that has a flat temporal and spatial profile, has been built, commissioned, and put into service as part of the LLNL Compton-scattering source program. This laser is based on an all-fiber oscillator and front-end amplification system, and provides both the laser light to generate the electrons as well as the rf signal that is amplified to accelerate them. Now, a new 11.424 GHz photoinjector is being developed, which has required a revised design of for the laser system. The higher frequency has placed more stringent requirements on the synchronization stability, delivered pulse length, and pulse rise times to maintain the desired emittance. Presented here are the overall design and measured performance of the current system and a discussion of what changes are being made to address observed shortcomings and more demanding requirements to make the system ready for the next-generation Compton-scattering source.

• S.V. Shchelkunov, J.L. Hirshfield
  Omega-P, Inc., New Haven, Connecticut
• S. Kazakov
  KEK, Ibaraki
• V.P. Yakovlev
  Fermilab, Batavia

Measurements are reported for a one-third version of a L-band high-power ferroelectric phase shifter. The device is designed to allow fast adjustments of cavity coupling in an accelerator where microphonics, RF source fluctuations, or another uncontrolled fluctuations could cause undesired emittance growth. Experimental measurements of switching speed, phase shift and insertion loss vs. externally-applied voltage are presented. An average switching rate of 0.5 ns or better for each degree of RF phase has been observed.

• F.V. Hartemann, F. Albert, G.G. Anderson, S.G. Anderson, C.P.J. Barty, A.J. Bayramian, S.M. Betts, T.S. Chu, R.R. Cross, C.A. Ebbers, S.E. Fisher, D.J. Gibson, D.P. McNabb, M. J. Messerly, M. Shverdin, C. Siders
  LLNL, Livermore, California
• E.N. Jongewaard, S.G. Tantawi, A.E. Vlieks
  SLAC, Menlo Park, California
• A. Ladran
  LBNL, Berkeley, California
• V.A. Semenov
  UCB, Berkeley, California

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

A precision, tunable gamma-ray source driven by a compact, high-gradient X-band linac is under development at LLNL. High-brightness, relativistic electron bunches produced by the linac interact with a Joule-class, 10 ps laser pulse to generate tunable gamma-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. The source will be used to excite nuclear resonance fluorescence lines in various isotopes; applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status will be presented.

• Zh.S. Gevorkian, S.G. Arutunian, K.B. Oganesyan
  YerPhI, Yerevan

Diffusive Radiation is originated by the passage of charged particles through a randomly inhomogeneous medium. DR appears when the conditions for multiple scattering of pseudophotons are fulfilled in the medium. Such a situation can be realized when a charged particle slides over a rough surface. One of the important properties of DR is that the maximum of emission lies at large angles from particle velocity direction. Therefore it can be used for detection of beam touch to the accelerators vacuum chamber wall in case when generated photons will be observed on the opposite side of vacuum chamber. Such a diagnostics can be especially useful for observation of storage rings beam halo.

• O. Williams, G. Andonian, E. Hemsing, J.B. Rosenzweig
  UCLA, Los Angeles, California
• M. Babzien, K. Kusche, J.H. Park, I. Pogorelsky, V. Yakimenko
  BNL, Upton, Long Island, New York

It is possible to obtain spectral and angular information of inverse Compton sources using only an x-ray imaging device and various foils with K-edges in the many keV energy range. Beam parameters are chosen such that on-axis photons are above the K-edge for a given material, where absorption is strong and there is relatively zero transmission. Photons observed off-axis are red-shifted and fall below the K-edge, therefore being transmitted and creating a “donut” pattern, or "lobes" in the ideal case for a circularly or linearly polarized laser, respectively. We present simulation and experimental results of the double differential spectrum (DDS) for angle and energy of Compton photons generated at the BNL ATF.

• H. Burkhardt, Y.I. Levinsen, S.M. White
  CERN, Geneva

The TOTEM experiment requires special high beta optics solutions. We report on studies of optics for an intermediate beta* = 90 m, as well as a solutions for a very high beta* of 1540 m, which respect all known constraints. These optics are rather different from the normal physics optics and will require global tune changes or adjustments.

• A.I. Drozhdin, N.V. Mokhov, S.I. Striganov
  Fermilab, Batavia

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.

With a fully-operational high-efficient collimation system in the LHC, nuclear interactions of circulating protons with residual gas in the machine beam pipe can be a major sources of beam losses in the vicinity of the collider detectors, responsible for the machine-induced backgrounds. Realistic modeling of elastic and inelastic interactions of 7-TeV protons with nuclei in the vacuum chamber of the cold and warm sections of the LHC ring - with an appropriate pressure profile - is performed with the STRUCT and MARS15 codes. Multi-turn tracking of the primary beams, propagation of secondaries through the lattice, their interception by the tertiary collimators TCT as well as properties of corresponding particle distributions at the CMS and ATLAS detectors are studied in great detail and results presented in this paper.

• S. Cavalier, M. Heller
  LAL, Orsay
• H. Burkhardt, P.M. Puzo, S.M. White
  CERN, Geneva

For luminosity and total cross section measurement, the standard LHC physics optics has been modified for the ATLAS experiment in the so-called high beta optics with a beta star of 2600m. The high beta optics takes into account the whole LHC ring. Protons are, then, tracked from the Interaction Point to the detectors. Tolerances on the beta star are given and the effect of misalignment errors is checked. We show the final High beta optics used and the impact of the misalignment effect on the measurement.

• J. Beebe-Wang
  BNL, Upton, Long Island, New York

Funding: Work performed under the auspices of the US DOE.

A staged approach towards the development of a high energy RHIC-based electron-ion collider has been proposed in BNL*. In the first stage, a medium-energy electron-ion collider (MEeIC) would be constructed. It would utilize a high energy ion beam, accelerated in one of the two existing rings of the RHIC facility, colliding with a medium energy (4GeV) electron beam, generated by a proposed energy-recovery linac. As a part of the design and investigation of the interaction region, it is necessary to estimate the level of background radiation in the physics experiment detector. The primary radiation distribution can be readily calculated by employing electromagnetic theory. However, the secondary radiation is due to a diffuse scattering of soft X-ray off rough surfaces. In this paper, we first calculate the primary radiation spectrum and apply the kinematic Born approximation deduced from the scattering dynamics. Next, the diffuse scattering cross section is calculated as a function of the material and surface properties of the MEeIC vacuum system. Finally, the minimization of the radiation background level by the choices of the material and surface properties is discussed.

*V. Ptitsyn et al., “MEeIC - staging approach to eRHIC”, these proceedings.

• M.D. Salt
  UMAN, Manchester
• R. Appleby, K. Elsener
  CERN, Geneva
• A. Ferrari
  Uppsala University, Uppsala

The CLIC beam delivery system focuses 1.5 TeV electron and positron beams to a nanometre-sized cross section when colliding them at the interaction point (IP). The intense focusing leads to large beam-beam effects, causing the production of beamstrahlung photons, coherent and incoherent electron-positron pairs, as well as a significant disruption of the main beam. The transport of the post-collision beams requires a minimal loss extraction line, with high acceptance for energy deviation and divergence. The current design includes vertical bends close to the IP in order to separate the charged particles with a sign opposite to the main beam into a diagnostic-equipped intermediate dump, whilst transporting the photons and the main beam to the main dump. Photon and charged particle losses on the collimators and dumps result in a complex radiation field and IP background particle fluxes. In this paper, the electromagnetic backgrounds at the IP, which arise from these losses, are calculated, and the potential impact on the detector is discussed.

• A.A. Mikhailichenko
  CLASSE, Ithaca, New York
• H. Aksakal
  N.U, Nigde

We consider a scheme for gamma-gamma collisions at ILC. In our scheme the electron beam from 5 GeV injector-Linacs, present in ILC scheme, used in FEL amplifier. The laser radiation from solid-state laser amplified in this FEL and directed to nearby IP point for further Compton back scattering. Two additional ~50 m helical undulators and master laser system of intermediate power required for this scheme at ILC.

• M. Fitterer, A.-S. Müller
  KIT, Karlsruhe
• E. Adli, H. Burkhardt, B. Dalena, G. Rumolo, D. Schulte
  CERN, Geneva
• I. Ahmed
  NCP, Islamabad
• A. Latina
  Fermilab, Batavia

We report about generic halo and tail simulations and estimates. Previous studies were mainly focused on very high energies as relevant for the beam delivery systems of linear colliders. We have now studied, applied and extended these simulations to lower energies as relevant for the CLIC drive beam.

• C.T. Rogers
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• G. Prior
  CERN, Geneva

In Muon Ionisation Cooling, closely packed high-field RF cavities are interspersed with energy-absorbing material in order to reduce particle beam emittance. Transverse focussing of the muon beams is achieved by superconducting magnets. This results in the RF cavities sitting in intense magnetic fields. Recent studies have shown that this may limit the peak gradient that can be achieved in the RF cavities. In this paper, we study the effect that a reduced RF gradient may have on the cooling performance of the Neutrino Factory lattice and examine methods to mitigate the effect.

• H.L. Owen, S. Alshammari, R. Appleby, R.J. Barlow, A.M. Toader
  UMAN, Manchester

The LHC Collimators are designed to remove halo particles such that they do not impinge onto either detectors or other vulnerable regions of the storage ring. However, the very high 7 TeV energy means that their design is critical, as is the modelling of the absorption, scattering and wakefield effects upon the passing bunches. Existing simulations are being performed using Sixtrack and K2. We compare these simulations with results obtained using the MERLIN code, which includes a fuller description of the scattering and wakefield processes.

• E. Laface, W. Scandale
  CERN, Geneva
• G. Cavoto
  INFN-Roma, Roma
• S. Peggs
  BNL, Upton, Long Island, New York

The UA9 experiment will take place in 2009 at the CERN-SPS and will evaluate the feasibility of silicon crystals as primary collimators for a storage ring. A crystal placed at 6 σ from the beam core will deviate protons towards two roman pots and a tungsten absorber (TAL). In this paper the authors show simulations of the expected beam dynamics and of the capture efficiency into the secondary collimator. The result of these simulations will guide us in interpreting the experimental data expected in UA9.

• C.B. Schroeder, E. Esarey, C.G.R. Geddes, W. Leemans, C. Tóth
  LBNL, Berkeley, California

Funding: Supported by the Office of Science, Office of High Energy Physics, of the U.S. DOE under Contract No. DE-AC02-05CH11231.

Laser-driven plasma-based accelerators have made rapid progress in the last several years, yielding high-quality GeV electron beams accelerated over several centimeters.* Due to the ultra-high accelerating gradients, employing laser-plasma-accelerator technology has the potential to significantly reduce the linac length (and therefore cost) of a future lepton collider. The prospects and design considerations for a next-generation electron-positron linear collider based on laser-plasma accelerators are discussed. Staging of ultra-high gradient laser-plasma accelerating structures is examined, and plasma density scaling laws are derived for relevant collider parameters. Emittance growth via beam-plasma scattering is analyzed. An example of self-consistent parameters for a 1 TeV laser-plasma-based collider is presented.

*W.P. Leemans et al., ‘‘GeV electron beams from a centimetre-scale accelerator,'' Nature Physics 2, 696 (2006).

• V. Guidi, S. Baricordi, P. Dalpiaz, M. Fiorini
  UNIFE, Ferrara
• A.G. Afonin, Y.A. Chesnokov, V.A. Maisheev, I.A. Yazynin
  IHEP Protvino, Protvino, Moscow Region
• G. Ambrosi, B. Bertucci, W.J. Burger, P. Zuccon
  INFN-PG, Perugia
• D. Bolognini, S. Hasan, A. Mozzanica, M. Prest
  Università dell'Insubria & INFN Milano Bicocca, Como
• G. Cavoto, R. Santacesaria, P. Valente
  INFN-Roma, Roma
• G. Della Mea, R. Milan, A. Vomiero
  INFN/LNL, Legnaro (PD)
• A.S. Denisov, Yu.A. Gavrikov, Yu.M. Ivanov, L.P. Lapina, L.G. Malyarenko, V. Skorobogatov, V.M. Suvorov, S.A. Vavilov
  PNPI, Gatchina, Leningrad District
• A.D. Kovalenko, A.M. Taratin
  JINR, Dubna, Moscow Region
• C. Luci
  Università di Roma I La Sapienza, Roma
• A. Mazzolari
  INFN-Ferrara, Ferrara
• W. Scandale
  CERN, Geneva
• E. Vallazza
  INFN-Trieste, Trieste

The H8RD22 collaboration has accomplished an extensive study of axial channeling in the external lines of the CERN SPS. For 400 GeV protons, it was recorded deflection by about 90% of the particles by a short crystal, by far exceeding the performance of previous experiments. Axial channeling with 150 GeV negative hadrons was also firmly observed with deflection capability comparable to the case of positive particles. Near-axis effect such as multiple-volume reflections in a single crystal as a result of the superposition of volume reflections by a series of parallel planes sharing the same axis was investigated with 400 GeV protons. Confirmation of theoretical expectation was observed, in particular most of the particles were deflected by about 50 urad, four times the deflection angle imparted by a single volume reflection of most efficient planes. In this case the angular acceptance was sensitively broader than for the case of channeling. In summary, channeling in axial mode and multi-volume reflections were proven to be two mechanisms for manipulation steering of high-energy particle beams, which side most established techniques such as planar channeling and volume reflection.*

*Contribution on behalf of the H8RD22 collaboration.

• S. Shiraishi
  Enrico Fermi Institute, University of Chicago, Chicago, Illinois
• R. Tesarek
  Fermilab, Batavia

Understanding beam loss in an accelerator is crucial to accelerator design and operation. Losses contribute to a shorter lifetime of a circulating beam, higher radiation doses to accelerator components, and backgrounds in experiments which use the beam. One source of beam loss is diffusion caused by effects such as beam scattering with residual gas in vacuum chamber, noise in the radio frequency acceleration system and power supplies, and beam-beam collisions. We measure the diffusion rate in the Fermilab Tevatron using the flying wire beam profile monitor. We have developed a new technique for interpreting the flying wire data. Using this technique, we measure the proton horizontal diffusion rate for ten stores in the Tevatron during colliding beam operation.

• Y.I. Levinsen, H. Burkhardt
  CERN, Geneva
• V. Talanov
  IHEP Protvino, Protvino, Moscow Region

We report on background studies for the LHC with detailed simulations. The simulations now include generation of beam-gas scattering in combination with multiturn tracking of protons. Low beta optics and available aperture files for this configuration have been used to generate loss maps according to the pressure distribution in the LHC.

• C. Steier, L. Yang
  LBNL, Berkeley, California

Funding: This work was supported by the Director, Office of Science, U. S. Department of Energy under Contract No. DE-AC02-05CH11231.

The Touschek lifetime in low energy or small emittance lepton storage rings strongly depends on the particle density in bunches. In the usual parameter range, this dominates other effects and the lifetime gets shorter with higher the bunch density, i.e. with smaller beam emittance. However, once one gets to extremely small horizontal emittances, this is no longer the case. Since the Touschek scattering process is an energy transfer from the transverse plane to the longitudinal one, the Touschek lifetime actually increases, once the transverse temperature (i.e. emittance) gets small enough. In the usual Touschek lifetime formulas, this is accounted for with a complicated multiparameter function (form factor). This paper presents to our knowledge the first direct measurements of the Touschek lifetime in this region of reversed dependence on horizontal emittance, as well as comparison with theory. The measurements were carried out at the ALS at reduced beam energy and ultrasmall horizontal emittance.

• A. Xiao, M. Borland
  ANL, Argonne

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

A high-brightness electron beam used for linac-based fourth-generation light sources such as X-ray free-electron lasers (FELs) and energy recovery linacs (ERLs) is often non-Gaussian distributed especially in the longitudinal direction. In order to study the intra-beam scattering effect (IBS) in such a beam, we added a slice analysis method to elegant. This paper explains this method and an application result to a possible ERL upgrade of the Advanced Photon Source.

• I.R.R. Shinton, R.M. Jones
  UMAN, Manchester

It is necessity to be able to accurately predict the performance of the any proposed baseline accelerator design in which the effects of couplers, trapped modes, Wakefields, realistic machining and alignment errors as well as numerous other important effects have been taken into consideration. Traditionally used numerical schemes (such as Finite element and Finite difference) require vast resources and time, not only that but the inclusion of realistic defects and misalignments into the baseline configuration will prove time consuming as it will potentially require remeshing of the problem. Here we present a mode matching scheme which utilises a globalised scattering matrix approach that allows large scale electromagnetic field calculations to be obtained rapidly and efficiently. The scalar product of all the S matrices used within this paper has been determined analytically and is calculated only once per transition, adding to the efficiency of the calculation. The influence of cell misalignments and cavity perturbations on the main accelerating linacs of XFEL and CLIC are exhibited. The wake-fields in super-structures and segments of entire modules are also presented

• M. P. Ehrlichman, G.H. Hoffstaetter
  CLASSE, Ithaca, New York

Funding: This work was supported by the National Science Foundation.

The theories of beam loss and emittance growth by Touschek and intra-beam scattering formulated for beams in storage rings have recently been extended to linacs. In most linacs, these effects are not relevant, but they become important in Energy Recovery Linacs (ERLs) not only because of their large current, but also because the deceleration of the spent beam increases the relative energy deviation and transverse oscillation amplitude of the scattered particles. In this paper, we describe a methodology for designing a collimator scheme to control where scattered particles are lost. The methodology is based on Touschek particle generation and tracking simulations implemented in {\tt BMAD}, Cornell's beam dynamics code. The simulations give the locations where scattering occurs and the locations where the scattered particles are lost. The simulations are used to determine the trajectory of the scattered particles, which are analyzed to determine optimal locations for collimators.

• Y. Alexahin
  Fermilab, Batavia

Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy

Existing codes for accelerator design (e.g. MAD) are not well suited for ionization cooling channels where particles exhibit strongly dissipative and nonlinear motion. A system of Mathematica programs was developed which allows to: 1) find periodic orbit and eigenvectors of the transfer matrix around it with account of (regular part of) ionization losses and feeddown effect from nonlinear fields; 2) compute emittance growth due to scattering and straggling, find equilibrium values (if exist); 3) analyze nonlinear effects such as dependence of tunes and damping rates on the amplitudes, resonance excitation; 4) perform tracking with account of stochastic processes. Underlying theory and application to helical cooling channel are presented.

• J. Shi, H. Chen, Q. Du, Y.-C. Du, W.-H. Huang, R.K. Li, C.-X. Tang, L.X. Yan
  TUB, Beijing
• D. Li
  LBNL, Berkeley, California

Funding: Supported by National Natural Science Foundation of China (No.10775080)

An S-band RF deflecting cavity has been developed and applied for measuring the bunch length at Tsinghua Thomson-Scattering X-ray Source (TTX). This paper briefly introduces the 3-cell pi-mode standing-wave deflecting cavity and reports the recent experiments of the beam diagnostics for the photo-cathode RF gun, which produces electron bunches with RMS length around 1-ps. It is also observed that the bunches are lengthened while the total charge increases, showing the strong space charge effect at a low beam energy.

• C. Sun, J.Y. Li, Y.K. Wu
  FEL/Duke University, Durham, North Carolina
• G. Rusev, A. Tonchev
  TUNL, Durham, North Carolina

A gamma-ray beam produced by Compton scattering of a laser beam and a relativistic electron beam has been used to determine electron beam parameters. In order to accurately measure the electron beam energy, a fitting model based upon Compton scattering cross section is introduced in this paper. With this model, we have successfully determined the energy of the electron beam in Duke storage ring with a relative uncertainty of 3× 10^-5 using a Compton gamma beam from the High Intensity γ-ray Source (HIγS) facility at Duke University.

• J.F. Power, J.D. Gilpatrick
  LANL, Los Alamos, New Mexico

Funding: US Department of Energy

Future improvements to the Los Alamos Neutron Scattering Center (LANSCE) include new Beam position and phase measuring systems that operate at 201.25 to 805 MHz. An effort is underway to build and test prototype electronics for these applications. We plan to use direct down conversion to 35 to 115 MHz followed by COTS FPGA hardware for in-phase and quadrature-phase (I/Q) signal processing. Self- calibration and system diagnostics circuits will be included. We are reporting on the status of these efforts.

• S. Wang
  CAEP/IFP, Mainyang, Sichuan

The capability of the chromatic correction of Zumbro Lens lies on the angle-position correlation, which is obtained by passing the beam through an expander or quadruples. However even after a long distance drift downstream the expander, the angle-position correlation can not be perfect because of the existence of finite emittance. This paper discusses the influence of the emittance to the chromatic correction and the optimization of beam status in phase space at the entrance of the expander.

• W. Bartmann, J. Barranco, M. Benedikt, B. Goddard, T. Kramer, Y. Papaphilippou, H. Vincke
  CERN, Geneva

Control of beam losses is an important aspect of the H^- injection system for the PS2, a proposed replacement of the CPS in the CERN injector complex. H^- ions may pass the foil unstripped or be partially stripped to excited H0 states which may be stripped in the subsequent strong-field chicane magnet. Depending on the choice of the magnetic field, atoms in the ground and first excited states can be extracted and dumped. The conceptual design of the waste beam handling is presented, including local collimation and the dump line, both of which must take into account the divergence of the beam from stripping in fringe fields. Beam load estimates and activation related requirements of the local collimators and dump are briefly discussed.

• B. Nash, S.L. Kramer
  BNL, Upton, Long Island, New York

The Touschek effect limits the lifetime for NSLS-II. The basic mechanism is Coulomb scattering resulting in a longitudinal momentum outside the momentum aperture. The momentum aperture results from a combination of the initial betatron oscillations after the scatter and the non-linear properties determining the resultant stability. We find that higher order multipole errors may reduce the momentum aperture, particularly for scattered particles with energy loss. The resultant drop in Touschek lifetime is minimized, however, due to less scattering in the dispersive regions. We describe these mechanisms, and present calculations for NSLS-II using a realistic lattice model including damping wigglers and engineering tolerances.

• N. Saotome, T. Furukawa, T. Inaniwa, Y. Iwata, T. Kanai, A. Nagano, K. Noda, S. Sato, T. Shirai, E. Takeshita
  NIRS, Chiba-shi
• T. Kohno
  TIT, Yokohama

The screen monitor system is an important tool for beam diagnostic of the high-energy-beam transport line at the Heavy-Ion Medical Accelerator in Chiba (HIMAC). We have developed a very thin fluorescent film and high speed charge-coupled-device camera. Because the fluorescent film is very thin (ZnS:Ag 2mg/cm³), the beam is measured with semi-non-destructively. Consequently we can use more than two monitors at the same time and multiple locations. Moreover we employ a high-speed three-processer for image processing, the system can be applied for online monitoring and interlock system (100Hz). When the beam profile measured by this system is inevitably changed over the setting tolerance during therapeutic irradiation for the patient, the beam is immediately turned off. The design and measurement result by irradiation test are discussed.

• A.Y. Murokh
  RadiaBeam, Marina del Rey
• E. Hemsing, J.B. Rosenzweig
  UCLA, Los Angeles, California

A Coherent Optical Transition Radiation (COTR) arising from the photo-injector electron beams spontaneous microbunching at optical frequencies has been recently observed in a number of experiments. This effect can lead to an undesirable optical background for OTR beam profile measurements at these facilities. A method to resolve this problem is proposed, based on selectively suppressing the back-scattered COTR using multiple scattering in the insertion foil. An analytical treatment of COTR dependence on the angular divergence in the radiating beam is presented, and the efficacy of the approach is illustrated with the numerical examples.

• A.V. Tyukhtin, T.Yu. Alekhina, E.G. Doil'nitsina, S.N. Galyamin
  Saint-Petersburg State University, Saint-Petersburg

Funding: Physical Faculty of St.Petersburg State University (14.10.08); SBIR DOE (DE-FG02-08ER85031)

Radiation of a charge crossing the boundary between vacuum and left-handed medium is analyzed. The medium is characterized by permittivity and permeability with frequency dispersion of “plasmatic” type. Such properties can be realized in some modern metamaterials with a relatively simple structure. Both the case of unbounded medium and the case of circular waveguide are considered. Analytical expressions for field components are obtained and algorithm of their computation is developed. The main attention is given to the analysis of radiation in vacuum region. In particular, it is shown that two types of radiation can be generated in this region. One of them is an ordinary transition radiation having relatively large magnitude. Another type of radiation can be named the “Cherenkov-transition” radiation. Conditions of generating this type of radiation are obtained. This effect and some another properties of radiation can be used for diagnostics of beams. For example, the detector with two energy thresholds can be designed.

• M.J. Bogan, S. Boutet, P. DeCorwin-Martin, D.G. Starodub
  SLAC, Menlo Park, California
• S. Bajt, H. Chapman, J. Schulz
  DESY, Hamburg
• A. Barty, W.H. Benner, M. Frank, S.P. Hau-Riege, B. Woods
  LLNL, Livermore, California
• J. Hajdu, B. Iwan, M.M. Seibert, N. Timneanu
  Uppsala University, Biomedical Centre, Uppsala
• S. Marchesini
  LBNL, Berkeley, California
• U. Rohner
  Tofwerk, Thun

Radiation damage limits the resolution of structural information obtained by X-ray diffraction. We are developing coherent diffractive imaging of biological specimens beyond conventional radiation damage resolution limits. The soft X-ray free-electron-laser (FEL) in Hamburg, FLASH*, was used to generate high-resolution low-noise coherent diffraction patterns from nanostructured nonperiodic objects before they turned into a plasma and exploded during single {10}-30 fs long X-ray pulses**,***. Iterative phase retrieval algorithms were used to reconstruct images of the objects****. Recent single particle diffraction experiments at FLASH, achieved in part due to the bunch train time pattern available from this superconducting linear accelerator, will be described. Data from single nanoparticles, their clusters and single cells will be discussed. Extending this approach to hard X-ray FELs, such as the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory, is anticipated to facilitate near atomic resolution imaging of nm-to-um-sized objects without the need for crystallization*****.

* Ayvazyan et al Eur Phys J D 2006 37 297
** Chapman et al Nat Phys 2006 2 839
*** Bogan et al Nano Lett 2008 8 310
**** Marchesini Rev Sci Instr 2007 78 011301
***** Neutze et al Nature 2000 406 752

• F.B. Rizzato, A. Endler, R.P. Nunes, R. Pakter, E.G. Souza
  IF-UFRGS, Porto Alegre

Funding: CNPq, Brazil; AFOSR FA9550-06-1-0345, USA

In this work we analyze the dynamics of mismatched inhomogeneous beams of charged particles. Initial inhomogeneities lead to propagating density waves across the beam core, and the presence of density waves eventually results in density build up and particle scattering. Particle scattering off waves in the beam core and the presence of resonances due to envelope mismatches ultimately generate a halo of particles with concomitant emittance growth. Emittance growth directly indicates when the beam relaxes to its final stationary state, and the purpose of the present paper is to describe halo and emittance in terms of test particles moving under the action of the mismatched inhomogeneous beam. To this end we develop an average Lagrangian approach for the beam where both density and envelope mismatches are incorporated. Test particle results compare well with full simulations.

• R. Busby, J.R. Cary, D.A. Dimitrov
  Tech-X, Boulder, Colorado
• I. Ben-Zvi, X. Chang, J.W. Keister, E.M. Muller, T. Rao, J. Smedley, Q. Wu
  BNL, Upton, Long Island, New York

Funding: The work at Tech-X Corp. is supported by the U. S. Department of Energy under the DE-FG02-06ER84509 SBIR grant.

The Relativistic Heavy Ion Collider (RHIC) contributes fundamental advances to nuclear physics by colliding a wide range of ions. A novel electron cooling section, which is a key component of the proposed luminosity upgrade for RHIC, requires the acceleration of high-charge electron bunches with low emittance and energy spread. A promising candidate for the electron source is the recently developed concept of a high quantum efficiency photoinjector with a diamond amplifier. To assist in the development of such an electron source, we have implemented algorithms within the VORPAL particle-in-cell framework for modeling secondary electron and hole generation, and for charge transport in diamond. The algorithms include elastic, phonon, and impurity scattering processes over a wide range of charge carrier energies. Results from simulations using the implemented capabilities will be presented and discussed.

• D.A. Dimitrov, R. Busby, J.R. Cary
  Tech-X, Boulder, Colorado
• I. Ben-Zvi, X. Chang, J.W. Keister, E.M. Muller, T. Rao, J. Smedley, Q. Wu
  BNL, Upton, Long Island, New York

Funding: The work at Tech-X Corp. is supported by the US DoE under grant DE-FG02-06ER84509.

A promising new concept of a diamond amplified photocathode for generation of high-current, high-brightness, and low thermal emittance electron beams was recently proposed* and is currently under active development. To better understand the different effects involved in the generation of electron beams from diamond, we have been developing models (within the VORPAL computational framework) to simulate secondary electron generation and charge transport. The currently implemented models include inelastic scattering of electrons and holes for generation of electron-hole pairs, elastic, phonon, and charge impurity scattering. We will present results from 3D VORPAL simulations with these capabilities on charge gain as a function of primary electron energy and applied electric field. Moreover, we consider effects of electron and hole cloud expansion (initiated by primary electrons) and separation in a surface domain of diamond.

*I. Ben-Zvi et al., Secondary emission enhanced photoinjector, C-AD Accel. Phys. Rep. C-A/AP/149, BNL (2004).

• B. Nash, S. Krinsky
  BNL, Upton, Long Island, New York

Single large angle Coulomb scattering is referred to as Touschek scattering. In addition to causing particle loss when the scattered particles are outside the momentum aperture, the process also results in a non-Gaussian tail, which is an equilibrium between the Touschek scattering and radiation damping. Here we present an analytical calculation for this equilibrium distribution.

• G. Rumolo, D. Schulte
  CERN, Geneva

The specification for vacuum pressure in the CLIC electron Main Linac critically depends on the fast ion instability. In fact, the maximum tolerable pressure value in the pipe of the Main Linac is dictated by the threshold above which the fast ion instability sets in over a CLIC bunch train. Previous calculation based on ion generation from residual gas ionization alone showed that, due to the loss of the trapping along the linac caused by the beam size shrinking from acceleration, a pressure as high as 10 nTorr could be accepted, higher than the tolerable value in the long transfer line. However, since the accelerated beam becomes transversely very small, its electric field can reach values above the field ionization threshold. When this happens, the whole space region with a sufficiently high electric field gets instantly fully ionized by the first bunch and the effect on the bunch train could be severe. We have modeled field ionization in our simulation code FASTION and re-evaluated the onset of fast ion instability in the Main Linac.

• D. Schulte
  CERN, Geneva

In the main linac of the compact linear collider (CLIC) , wakefield induced multi-bunch effects are important. They have a strong impact on the choice of accelerating structure design. The paper presents the limit for the wakefield that one bunch exerts on the next. It also gives estimates for the allowed level of persistent wake fields and on the resistive wall wakefield.

• S.A. Martin, R. Gebel, A. Lehrach, B. Lorentz, M. Nekipelov, D. Prasuhn, F. Rathmann, H.-J. Stein, H. Stockhorst, D.M. Welsch
  FZJ, Jülich
• A. Garishvili, A.N. Nass, E. Steffens
  University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
• P. Lenisa, M. Statera
  INFN-Ferrara, Ferrara

The PAX Collaboration is planning experiments using polarized Antiprotons. The only experimentally proven method so far which could lead to the production of polarized antiprotons is the spin-filtering. In particular, spin-filtering has been used to generate polarized protons in an experiment at the Heidelberg TSR*. In order to optimize spin-filtering for the production of polarized antiprotons dedicated experiments are planned at COSY with protons and AD (CERN) with antiprotons. The experimentation at COSY has already started in 2007. A decisive experiment has been performed to settle a long controversy about the role of electrons in the polarization buildup by spin-filtering. Instead of studying the polarization buildup in an initially unpolarized beam, the inverse situation was investigated by observation of depolarization of an initially polarized beam. For the first time the electrons of the electron cooler have been used as a target to study their depolarizing effects on the stored beam. At the same time a series of machine experiments have been performed to study the beam lifetime at different energies.

*F. Rathmann et al., Phys. Rev. Lett. 71, 1993, p.1379