Keyword: photon
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MOPEA022 Beam Profile Measurement for High Intensity Electron Beams electron, laser, scattering, diagnostics 118
 
  • T. Weilbach, K. Aulenbacher, M.W. Bruker
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  
  Recent developments in the field of high intensity electron beams in the regime below 10 MeV, e.g. energy recovery linacs or magnetized high energy electron coolers, have led to special demands on the beam diagnostics. Since commonly used diagnostic tools like synchrotron radiation and scintillation screens are ineffective or not able to withstand the beam power without being damaged, new methods are needed. Hence a beam profile measurement system based on beam induced fluorescence (BIF) was built. This quite simple system images the light generated by the interaction of the beam with the residual gas onto a PMT. A more elaborated system, the Thomson Laser Scanner (TLS) - the non-relativistic version of the Laser Wire Scanner - is proposed as a method for non-invasive measurement of all phase space components, especially in the injector and merger parts of an ERL. Both methods are implemented in a 100 keV photo gun. Beam profile measurements with BIF as well as first results of the TLS will be presented.  
 
MOPEA026 X-ray Powder Diffraction Beamline for the Iranian Light Source Facility electron, synchrotron, focusing, brilliance 130
 
  • H. Khosroabadi, S. Amiri, H. Ghasem, A. Gholampour
    ILSF, Tehran, Iran
  • H. Ghasem
    IPM, Tehran, Iran
  
  Iranian Light Source Facility (ILSF) project has been initiated since 2010 in order to design and construction of a synchrotron facility in Iran. In parallel with the machine’s activities, scientific committee, users community and beamline technical group are working on different aspects of the scientific and beamline design issues for the operating phase after construction*. X-ray powder diffraction beamline is one of the most priorities in ILSF due to wide range of applications and big potential user community in Iran. Conceptual design report of this beamline operating in other worldwide synchrotrons have been studied and compared in details. The light source and schematic design of the beamline has been prepared in this study. Then, the parameters have been calculated and have been optimized by employing computational software such as XOP and SHADOW**. The optical properties of the optical elements such as reflectivity, absorbance, Bragg diffraction, rocking curve, aberration, etc have been studied at this design, and the results have been compared with the other published results. The outcome and final results of this design progress will be discussed in details.
References:
* Conceptual Design Report (2011, summer), ILSF, http://ilsf.ipm.ac.ir/.
** http://www.esrf.eu/UsersAndScience/Experiments/TBS/SciSoft/xop2.3.
 
 
MOPEA027 New Optics with Emittance Reduction at the SPring-8 Storage Ring optics, emittance, injection, sextupole 133
 
  • Y. Shimosaki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, T. Nakamura, T. Nakanishi, H. Ohkuma, M. Oishi, M. Shoji, K. Soutome, S. Takano, M. Takao
    JASRI/SPring-8, Hyogo-ken, Japan
  
  The machine tuning of a new optics is in progress at the SPring-8 storage ring, in order not only to provide brilliant photons for current users but also to study a strategy of a lattice design and a tuning scenario for the upgrade project SPring-8 II. The natural emittance is reduced to 2.4 nmrad from the present value of 3.4 nmrad without any change of magnet positions. The flux density 1.3 times higher than the present was observed at the diagnostics beamline. The nominal injection efficiency of the order of 80 % has been achieved (the present: 92 %) by correcting the error of the optics function, by adjusting the strength of the injection magnets and by optimizing the sextupole magnetic fields. The beam lifetime was 13 h at 1 mA / bunch (the present: 22 h), and the momentum aperture estimated from the measurement of the Touschek lifetime was 2.3 % (the present: 2.8 %). Though these are tolerable to the user operation, further optimization of the sextupoles is ongoing. After verifying the photon beam performance at beamlines, this new optics will be applied to the user operation. The optics design and its beam performance will be presented in detail.  
 
MOPEA028 Present Status of the KEK PF-Ring and PF-AR undulator, injection, polarization, linac 136
 
  • K. Tsuchiya, S. Asaoka, K. Haga, K. Harada, T. Honda, Y. Honda, M. Isawa, Y. Kamiya, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, T. Nogami, T. Obina, T. Ozaki, H. Sagehashi, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, K. Shinoe, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, Y. Tanimoto, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
  • H. Takaki
    ISSP/SRL, Chiba, Japan
  
  In KEK, two synchrotron light sources have been operated. One is the 2.5 GeV Photon Factory storage ring (PF-ring) and the other is the 6.5 GeV Photon Factory advanced ring (PF-AR). In this paper, present operational status and recent R&D activities such as fast local bump system for helicity switching undulator, hybrid injection system, pulsed-sextupole injection, etc. Futhermore, upgrade plan towards the top-up injection of 6.5 GeV PF-AR ring is underway. Construction of the straight injection tunnel from linac to PF-AR will be started next fiscal year. Design detail and strategy for the injection scheme will be reported.  
 
MOPME003 Development of Diamond Sensors for Beam Halo and Compton Spectrum Diagnostics After The Interaction Point of ATF2 collimation, electron, simulation, vacuum 470
 
  • S. Liu, P. Bambade
    LAL, Orsay, France
  • S. Bai
    IHEP, Beijing, People's Republic of China
  • T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  
  ATF2 is a low energy (1.3GeV) prototype of the final focus system for ILC and CLIC linear collider projects. A major issue at ATF2 and in linear colliders is to control the beam halo, which consists of tails extending far beyond the Gaussian core of the beam. At present there is no dedicated collimation for the beam halo at ATF2, and the transverse distribution near the interaction point is not well known. The development of a sensor based on CVD diamond to scan the beam halo in the vacuum chamber a few meters after the interaction point is presented. This system also aims to detect the Compton recoil electrons generated by the laser interferometer (Shintake monitor) used to measure the beam size at the interaction point of ATF2.  
 
MOPME004 Fast Luminosity Monitoring using Diamond Sensors for Super Flavour Factories luminosity, scattering, electron, positron 473
 
  • C. Rimbault, P. Bambade
    LAL, Orsay, France
  
  Super flavour factories aim to reach very high luminosities thanks to a new concept whereby the ultra-low emittance beams collide with a large crossing angle. Fast luminosity measurements are needed as input to luminosity optimization and feedback in the presence of dynamic imperfections. The required small relative precision can be reached exploiting the very large cross section of the radiative Bhabha process at zero photon scattering angle. The instrumental technique selected to sustain the large particle fluxes is based on diamond sensors to be positioned via moveable stages immediately outside the beam pipe, at locations chosen to minimize the contamination from other particle loss mechanisms.  
 
MOPME011 Investigation of the Applicability of Parametric X-ray Radiation for Transverse Beam Profile Diagnostics radiation, diagnostics, electron, background 491
 
  • G. Kube, C. Behrens
    DESY, Hamburg, Germany
  • A.S. Gogolev, Yu.A. Popov, A. Potylitsyn
    TPU, Tomsk, Russia
  • W. Lauth
    IKP, Mainz, Germany
  • S. Weisse
    DESY Zeuthen, Zeuthen, Germany
  
  Transverse beam profile diagnostics in electron linacs is widely based on optical transition radiation (OTR) as standard technique which is observed in backward direction when a charged particle beam crosses the boundary between two media with different dielectric properties. The experience from modern linac based light sources like LCLS or FLASH shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. A possibility to overcome this limitation is to measure at much shorter wavelengths, i.e. in the X-ray region, using parametric X-ray radiation (PXR) which additionally offers the advantage to be generated at crystal planes oriented under a certain angle to the crystal surface, thus allowing a spatial separation from a possible COTR background *. A first test experiment has been performed at the Mainz Microtron MAMI (University of Mainz, Germany) in order to study the applicability of PXR for beam diagnostics, and the status of this experiment will be presented.
* A. Gogolev, A. Potylitsyn, G. Kube, Journal of Physics 357 (2012) 012018
 		 
 
MOPME036 Prototype Experiment Preparation of a 54.167MHz Laser Wire System for FEL-THz Facility at CAEP laser, electron, FEL, cathode 550
 
  • D. Wu
    TUB, Beijing, People's Republic of China
  • W. Bai, M. Li, H. Wang, J. Wang, X. Yang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  In this paper, a prototype experiment preparation of a 54.167 MHz laser wire system is presented, which will be used to measure the beam size of a CW DC gun built as an electron source of FEL-THz facility in China Academmy of Engineering Physics (CAEP). The rms beam size is less than 1 mm and the average current of the electron beam is more than 1 mA. This new-type LW system ultilizes the excess power other the photocathode drive laser and becomes much cheaper and simpler. Plus, it can distinguish beams with different energies which are very close in ERLs. The system layout and the simulation results are also presented.  
 
MOPME077 Electro-0ptical Bunch Profile Measurement at CTF3 laser, electron, vacuum, polarization 658
 
  • R. Pan, A. Andersson, W. Farabolini, A. Goldblatt, T. Lefèvre, M. Martyanov, S. Mazzoni, S.F. Rey, L. Timeo
    CERN, Geneva, Switzerland
  • W.A. Gillespie, R. Pan, D.A. Walsh
    University of Dundee, Nethergate, Dundee, Scotland, United Kingdom
  • S.P. Jamison
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  A new electro-optic bunch profile monitor has recently been installed in CLIC Test Facility 3 at CERN. The monitor is based on an electro-optic spectral decoding scheme which reconstructs the longitudinal profile of the electron bunch by measuring its Coulomb field. The system uses a 780 nm fibre laser system, transported over a 20m long distance to the interaction chamber, where a ZnTe crystal is positioned close to the beam. The assembly also contains a traditional OTR screen, which is coupled to a second optical line and used to adjust the temporal overlap between the laser and the electron pulse. This paper presents the detection system in detail, as well as reporting on the first measurements performed with beam.  
 
MOPWA053 Sub-Micrometre Resolution Laserwire Transverse Beam Size Measurement System laser, electron, alignment, background 795
 
  • L.J. Nevay, G.A. Blair, S.T. Boogert, V. Karataev, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • A.S. Aryshev, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • L. Corner, R. Walczak
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  
  Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project Eu-CARD, grant agreement no. 227579
We present the results from the laserwire system at the Accelerator Test Facility 2 (ATF2) during recent operation after relocation to the virtual image point of the ATF2 final focus. The characterisation of the 150 mJ, 77 ps long laser pulses at a scaled virtual interaction point is used to deconvolve the transverse laserwire profile demonstrating a 1.16 ± 0.06 um vertical electron beam profile. Horizontal laserwire scans were used in combination with the vertical scans to measure the electron beam size using a full overlap integral model due to the problems presented by a large aspect ratio electron beam. 		 
 
MOPWA060 DITANET - An International Network in Beam Diagnostics diagnostics, electron, instrumentation, synchrotron 813
 
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: Work supported by the EU under contract 215080.
Beam diagnostics systems are essential constituents of any particle accelerator; they reveal the properties of a beam and how it behaves in a machine. Without an appropriate set of diagnostic elements, it would simply be impossible to operate any accelerator complex, let alone optimize its performance. Beam diagnostics is also a rich field in which a great variety of physical effects are made use of and consequently provides a wide interdisciplinary base for the training of researchers. The DITANET Consortium develops beyond state-of-the-art beam diagnostic techniques for hadron and electron accelerators and trained more than 20 researchers between 2008 and 2012. This contribution summarizes the network's research outcomes in beam instrumentation and diagnostics. 		 
 
MOPWA078 The Calibration of the PEPPo Polarimeter for Electrons and Positrons positron, electron, target, polarization 861
 
  • A.H. Adeyemi
    JLAB, Newport News, Virginia, USA
  • E. J-M. Voutier
    LPSC, Grenoble, France
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The PEPPo (Polarized Electrons for Polarized Positrons) experiment at Jefferson Laboratory investigated the polarization transfer from longitudinally polarized electrons to longitudinally polarized positrons, with the aim of developing this technology for a low energy (~MeV) polarized positron source. Polarization of the positrons was measured by means of a Compton transmission polarimeter where incoming positrons transfer their polarization into circularly polarized photons that were subsequently analyzed by a thick polarized iron target. The measurement of the transmitted photon flux with respect to the orientation of the target polarization (±) or the helicity (±) of the incoming leptons provided the measurement of their polarization. Similar measurements with a known electron beam were also performed for calibration purposes. This presentation will describe the apparatus and calibrations performed at the injector at the Jefferson Laboratory to measure positron polarization in the momentum range 3.2-6.2 MeV/c, specifically to quantify the positron analyzing power from electron experimental data measured over a comparable momentum range.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes 		 
 
MOPWA079 Characterization of the Analyzing Target of the PEPPo Experiment target, polarization, positron, electron 864
 
  • O. Dadoun
    LAL, Orsay, France
  • E. Froidefond, E. J-M. Voutier
    LPSC, Grenoble, France
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Various methods have been investigated over the past decades for the production of polarized positrons. The purpose of the PEPPo (Polarized Electrons for Polarized Positrons) experiment is to demonstrate, for the first time, the production of polarized positrons from a polarized electron beam. This two-step process involves the production of circularly polarized photons in a high Z target via the bremsstrahlung process followed, within the same target, by the conversion of polarized photons into polarized e+e− pairs through the pair creation process. The PEPPo experiment was performed in Spring 2012 at the injector of the Jefferson Laboratory using a highly spin-polarized (~85%) 8.3 MeV/c electron beam. The positron polarization was measured by means of a Compton transmission polarimeter over the momentum range from 3.2 MeV/c to 6.2 MeV/c. This presentation will discuss the experimental set-up with a special emphasis on the analyzing magnet constituting the polarization filter of the experiment. The knowledge of the analyzing target polarization will be discussed on the basis of simulations and calibrated to experimental data
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes 		 
 
MOPWA080 Design of a Fast, XFEL-quality Wire Scanner electron, radiation, vacuum, instrumentation 867
 
  • M.A. Harrison, R.B. Agustsson, P.S. Chang, T.J. Hodgetts, A.Y. Murokh, M. Ruelas
    RadiaBeam, Santa Monica, USA
  
  RadiaBeam Technologies, in collaboration with the Pohang Accelerator Laboratory, has designed and built a fast wire scanner for transverse beam size measurements in the XFEL Injector Test Facility. The wire scanner utilizes three 25-micron diameter tungsten wires mounted vertically, horizontally, and diagonally on a single alumina card to measure the transverse beam size down to 10 microns with sub-micron accuracy of a 139-MeV electron beam. A double-ended design using dual bellows for actuation is used to reduce the vibrations of the wire holder during motion and negate the effects of air pressure on positioning. The servomotor-driven system is capable of performing full horizontal, vertical, and 45-degree scans in under a minute. Algorithms are presented for removing the broadening effect of the wires' thickness from the scanning data to measure beams that are as small or smaller than the wires. Furthermore, we present formulas for determining the beam's transverse spatial sizes (horizontal and vertical spot size and correlation) from the scan data.  
 
MOPWO004 Simulations and Studies of Electron Beam Dynamics under Compton Back-scattering for the Compact X-ray Source ThomX electron, simulation, wakefield, collective-effects 888
 
  • I.V. Drebot, C. Bruni, N. Delerue, T. Demma, A. Variola, Z.F. Zomer
    LAL, Orsay, France
  • A. Loulergue
    SOLEIL, Gif-sur-Yvette, France
  
  Funding: This work is supported by the French "Agence Nationale de la Recherche" under reference ANR-10-EQPX-51, and also by grants from Région Ile-de-France, Université Paris-Sud and IN2P3/CNRS.
In this article are presented beam dynamics investiga- tions of a relativistic electron bunch in the compact storage ring ThomX (50 MeV), which is under construction at LAL to produce hard X-ray using Compton Back-Scattering (CBS). The effect of CBS has been implemented in a 6D tracking code. In addition to CBS, the influence of lattice non linearities and various collective effects on the flux of scattered Compton photons is investigated. 		 
 
TUOCB102 SPARC_LAB Recent Results laser, electron, plasma, FEL 1114
 
  • M. Ferrario, D. Alesini, M.P. Anania, A. Bacci, M. Bellaveglia, M. Castellano, E. Chiadroni, D. Di Giovenale, G. Di Pirro, A. Drago, A. Esposito, A. Gallo, G. Gatti, A. Ghigo, T. Levato, A. Mostacci, L. Palumbo, A.R. Rossi, B. Spataro, C. Vaccarezza, F. Villa
    INFN/LNF, Frascati (Roma), Italy
  • A. Cianchi
    INFN-Roma II, Roma, Italy
  • G. Dattoli, E. Di Palma, L. Giannessi, A. Petralia, C. Ronsivalle, V. Surrenti
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • C. De Martinis
    INFN/LASA, Segrate (MI), Italy
  • R. Faccini
    INFN-Roma, Roma, Italy
  • M. Gambaccini
    INFN-Ferrara, Ferrara, Italy
  • D. Giulietti
    UNIPI, Pisa, Italy
  • L.A. Gizzi, L. Labate
    CNR/IPP, Pisa, Italy
  • S. Lupi
    Università di Roma I La Sapienza, Roma, Italy
  • V. Petrillo, L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • J.V. Rau
    ISM-CNR, Rome, Italy
  • G. Turchetti
    Bologna University, Bologna, Italy
  
  A new facility named SPARC_LAB (Sources for Plasma Accelerators and Radiation Compton with Lasers and Beams) has been recently launched at the INFN National Labs in Frascati, merging the potentialities of the an ultra-brilliant electron beam photoinjector and of a high power Ti:Sa laser. The test facility is now completed, hosting a 150 MeV high brightness electron beam injector which feeds a 12 meters long undulator. Observation of FEL radiation in variuous configurations has been performed. In parallel to that a 200 TW laser that is linked to the linac and devoted to explore laser-matter interaction, in particular with regard to laser-plasma acceleration of electrons (and protons) in the self injection and external injection modes. The facility will be also used for particle driven plasma acceleration experiments (the COMB experiment). A Thomson scattering experiment coupling the electron bunch to the high-power laser to generate coherent monochromatic X-ray radiation is also in the commissioning phase. We report in this paper the recent results obtained at the SPARC_LAB facility.  
slides icon Slides TUOCB102 [12.874 MB]  
 
TUXB201 Short-pulse Operation of Storage Ring Light Sources radiation, storage-ring, electron, optics 1129
 
  • A.-S. Müller
    KIT, Karlsruhe, Germany
  
  Short-pulse operation of synchrotron light source storage rings can be useful for both the production of IR and THz-band radiation and high repetition rate pump-probe science in the X-ray regime. Different approaches to short-pulse generation include low-alpha optics configurations, two-frequency RF potential manipulation, laser-induced femtoslicing, longitudinal crab-cavity deflection and pseudo-bunch operation with a fast kicker to isolate a single bunch. This talk should review each of these techniques and discuss implications for machine operation in terms of pulse length, beam intensity, beam stability, pulse repetition rate, output radiation beam quality and potential applications.  
slides icon Slides TUXB201 [12.058 MB]  
 
TUOAB201 Ultra-Short X-ray Pulse Generation by Electron Beam Slicing in Storage Rings electron, storage-ring, linac, emittance 1134
 
  • L.-H. Yu, F.J. Willeke
    BNL, Upton, Long Island, New York, USA
  
  Funding: Department of Energy, USA
We propose a new method to generate ultra-short x-ray pulses using focused short low energy (5-10MeV) electron bunch to slice a short electron bunch from the electron bunches in a synchrotron radiation storage ring. When the low energy electron bunch crosses from top the high energy electron bunch at right angle, its coulomb force will kick a short slice of high energy electrons away from the core of the storage ring electron bunch. When the low energy electron bunch (about 50 pC) is focused to about 50 micron size and compressed to about 150fs bunch length and is positioned on top of the high energy electron bunch by a distance about 30 micron, the coulomb force is sufficient to give a kick vertically to the electrons within a short slice of the storage ring bunch about 200 fs long with a deflection about 4 micro-radian. This is sufficient to deflect the slice away from the core by a separation of 5 times the angular divergence of the beam. The separated slice when passing through an undulator, will radiate ulstra-short x-ray pulses at about 200 fs. We discuss the advantages and challenges of this new method. We provide data to demonstrate the feasibility of this method. 		 
slides icon Slides TUOAB201 [1.578 MB]  
 
TUPEA004 The Free-electron Laser FLASH at DESY FEL, gun, linac, undulator 1167
 
  • M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
    DESY, Hamburg, Germany
  
  The free-electron laser FLASH at DESY routinely produces up to several thousand photon pulses per second with wavelengths ranging from 44 nm down to as low as 4.25 nm and with pulse energies of up to 400μJoule. After a significant technical upgrade in 2010, which included an energy upgrade to 1.25 GeV and linearization of the longitudinal phase space by 3-rd harmonic cavities, emphasis was put on consolidation and automatization of operational procedures and better control of the electron/photon beam properties. Some highlights are: on-line measurements of the electron bunch-length in the regime of several 10 fs to 100 fs, reaching into the water window, increased photon pulse energies and the improved machine reproducibility. Moreover, first evidence of HHG seeding was found at the sFLASH experiment in spring 2012. Construction work is ongoing for a 2-nd beam-line (FLASH-2) for which commissioning will start in late 2013.  
 
TUPEA005 Effects of Quantum Diffusion on Electron Trajectories and Spontaneous Synchrotron Radiation Emission electron, radiation, undulator, synchrotron 1170
 
  • I.V. Agapov, G. Geloni
    XFEL. EU, Hamburg, Germany
  • O.V. Chubar
    BNL, Upton, Long Island, New York, USA
  
  For various cases, e.g. in the long undulator sections of the European XFEL, quantum diffusion and energy loss have a noticable effect on the electron trajectory, which in turn affects the properties of the emitted radiation. We discuss approaches to modelling the electron dynamics taking this into account and the effect it has on spontaneous radiation emission.  
 
TUPEA011 Double Stage Seeded FEL with Fresh Bunch Injection Technique at FERMI@Elettra FEL, laser, electron, undulator 1185
 
  • S. Di Mitri, E. Allaria, D. Castronovo, P. Cinquegrana, P. Craievich, G. D'Auria, M.B. Danailov, G. De Ninno, A.A. Demidovich, B. Diviacco, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, G. Gaio, L. Giannessi, R. Ivanov, B. Mahieu, N. Mahne, I. Nikolov, F. Parmigiani, G. Penco, L. Raimondi, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, D. Zangrando, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  
  During the month of October 2012 the commissioning of the light source FEL-2 at FERMI was successfully concluded. Fermi FEL-2 is the first seeded FEL operating with a double stage cascade in the "fresh bunch injection" mode*. The two stages are two high gain harmonic generation FELs where the first stage is seeded by the 3rd harmonic of a Ti:Sa laser system, which is up converted to the 4th-12th harmonic. The output of the first stage is then used to seed the second stage. A final wavelength of 10.8 nm was obtained as the 24th harmonic of the seed wavelength at the end of the two frequency conversion processes, demonstrating that the FEL is capable of producing single mode narrow bandwidth pulses with an energy of several tens ofμjoules. We report on the experimental characterisation of the FEL performances in this configuration.
* I. Ben-Zvi, K. M. Yang, L. H. Yu, ”The ”fresh-bunch” technique in FELs”, NIM A 318 (1992), p 726-729 		 
 
TUPEA058 The Conceptual Design of CLARA, A Novel FEL Test Facility for Ultrashort Pulse Generation FEL, electron, laser, linac 1265
 
  • J.A. Clarke, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, P.A. Corlett, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, L. Ma, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, H.L. Owen, R.N.C. Santer, Y.M. Saveliev, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R. Appleby, M. Serluca, G.X. Xia
    UMAN, Manchester, United Kingdom
  • R.J. Barlow, A.M. Kolano
    University of Huddersfield, Huddersfield, United Kingdom
  • R. Bartolini, I.P.S. Martin
    Diamond, Oxfordshire, United Kingdom
  • N. Bliss, R.J. Cash, G. Cox, G.P. Diakun, A. Gallagher, D.M.P. Holland, B.G. Martlew, M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • S.T. Boogert
    Royal Holloway, University of London, Surrey, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • L.T. Campbell, B.W.J. MᶜNeil
    USTRAT/SUPA, Glasgow, United Kingdom
  • S. Chattopadhyay
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • D. Newton, A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  
  The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.  
 
TUPFI005 Synchrotron-Radiation Photon Distribution for Highest Energy Circular Colliders scattering, radiation, vacuum, electron 1340
 
  • G.H.I. Maury Cuna
    CINVESTAV, Mérida, Mexico
  • G. Dugan, D. Sagan
    CLASSE, Ithaca, New York, USA
  • F. Zimmermann
    CERN, Geneva, Switzerland
  
  Funding: Acknowledgements to CINVESTAV, CERN and EPLANET project.
At high energies, beam-induced synchrotron radiation is an important source of heating, beam-related vacuum pressure increase, and primary photoelectrons, which can give rise to an electron cloud. The photon distribution along the beam pipe wall is a key input to codes such as ECLOUD and PyECLOUD, which model the electron cloud build-up. For future high-energy colliders, like TLEP or SHE-LHC, photon stops and antechambers are considered in order to facilitate cooling and vacuum pressure control. We use the Synrad3D code developed at Cornell to simulate the photon distribution for the LHC. 		 
 
TUPFI059 Summary of Dense Hydrogen Gas Filled RF Cavity Tests for Muon Acceleration proton, electron, plasma, ion 1481
 
  • K. Yonehara, M. Chung, M.R. Jana, M.A. Leonova, A. Moretti, A.V. Tollestrup
    Fermilab, Batavia, USA
  • B.T. Freemire, P.M. Hanlet, Y. Torun
    IIT, Chicago, Illinois, USA
  • R.P. Johnson
    Muons. Inc., USA
  
  Dense hydrogen gas filled RF cavity has a great potential to accelerate a large phase space muon beam in a strong magnetic field. The concept of novel RF cavity has been demonstrated by using an intense proton beam at Fermilab. The experimental result was agreed extremely well with the conventional dilute plasma physic. Based on the model, the beam-induced plasma in the gas filled RF cavity could be controlled by adding a small amount of electronegative gas in dense hydrogen gas. Overview of these experiments will be shown in this presentation.  
 
TUPME006 Simulation of Stress in Positron Targets for Future Linear Colliders target, positron, undulator, electron 1571
 
  • F. Staufenbiel, S. Riemann
    DESY Zeuthen, Zeuthen, Germany
  • O.S. Adeyemi, V.S. Kovalenko, G.A. Moortgat-Pick, A. Ushakov
    University of Hamburg, Hamburg, Germany
  
  Future linear collider projects require intense positron sources with yields of about 1014 positrons per second. The positron source for the ILC is based on a helical undulator passed by the accelerated electron beam to create an intense circularly polarized photon beam. The positron beam produced by these photons is longitudinally polarized. The intense photon beam causes rapid temperature increase in the target material resulting in periodic stress. The average and peak thermal and mechanical load are simulated. Implications due to long-term target irradiation are considered.  
 
TUPME025 Calculation of the Equilibrium Parameters for the Compact Ring of TTX emittance, scattering, electron, storage-ring 1625
 
  • H.S. Xu, W.-H. Huang, C.-X. Tang
    TUB, Beijing, People's Republic of China
  • S.-Y. Lee
    IUCEEM, Bloomington, Indiana, USA
  
  Intra-Beam Scattering (IBS) can cause emittance growth in high intensity low energy beams. We study its effect on the compact low energy electron storage ring, proposed for Tsinghua Thomson Scattering X-ray source (TTX). For a single bunch with peak current at about 17A and re-entrant type normal conducting RF cavity with peak voltage at 15kV, the equilibrium horizontal and vertical emittances are 2.9 and 0.3 μm, and the rms momentum spread and bunch length are about 0.2%, and 23ps. In this paper, we report the methods and results of the IBS calculation.  
 
TUPME067 Design Concept of a Gamma-gamma Higgs Factory Driven by Thin Laser Targets and Energy Recovery Linacs laser, electron, target, collider 1721
 
  • Y. Zhang
    JLAB, Newport News, Virginia, USA
  
  Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177.
A gamma-gamma collider has long been considered an option for a Higgs Factory. Such photon colliders usually rely on Compton back-scattering for generating high energy gamma photons and further Higgs bosons through gamma-gamma collisions. The presently existing proposals or design concepts all have chosen a very thick laser target (i.e., high laser photon intensity) for Compton scatterings. In this paper, we present a new design concept of a gamma-gamma collider utilizing a thin laser target (i.e., relatively low photon density), thus leading to a low electron to gamma photon conversion rate. This new concept eliminates most useless and harmful low energy soft gamma photons from multiple Compton scattering so the detector background is improved. It also greatly relaxes the requirement of the high peak power of the laser, a significant technical challenge. A high luminosity for such a gamma-gamma collider can be achieved through an increase of the bunch repetition rate and current of the driven electron beam. Further, multi-pass recirculating linac could greatly reduce the linac cost and energy recovery is required to reduce the needed RF power. 		 
 
TUPWO003 CLIC 3 TeV Beam Size Optimization with Radiation Effects radiation, quadrupole, lattice, dipole 1877
 
  • O.R. Blanco, P. Bambade
    LAL, Orsay, France
  • R. Tomás
    CERN, Geneva, Switzerland
  
  Horizontal beamsize contribution due to radiation on bending magnets is calculated using theoretical results and recent improvements in mapclass (Mapclass2). In order to verify the code and validity of its approximations, a simple lattice with no geometrical nor chromatic aberrations, one dipole and a final drift has been used to compare Mapclass2 calculations and Placet tracking results. CLIC 3TeV lattice is optimized including the radiation effects. Current results show that correction of chromatic aberrations impose constraints in radiation improvement.  
 
WEZB101 Status of the European XFEL linac, undulator, electron, gun 2058
 
  • M. Hüning
    DESY, Hamburg, Germany
  
  The European XFEL is one of the world's largest accelerators presently under construction. The facility includes a 17.5 GeV superconducting linac with more than 3 km of electron beam transport lines and up to 5 FEL undulators. In mid-2013 the underground civil construction will finish. With most of the large scale production in full swing and first accelerator components installed, this talk should present the XFEL facility status and plans for accelerator commissioning including prospects for first XFEL experiments in Hamburg.  
slides icon Slides WEZB101 [16.980 MB]  
 
WEOAB203 The PEPPo Concept for a Polarized Positron Source positron, electron, polarization, target 2088
 
  • E. J-M. Voutier
    LPSC, Grenoble, France
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Polarized positron beams are identified as an essential ingredient for the experimental program at the next generation of lepton accelerators (JLab, Super KEK B, ILC, CLIC). A proof-of-principle experiment for a new method to produce polarized positrons has recently been performed at the Jefferson Laboratory. The PEPPo (Polarized Electrons for Polarized Positrons) concept relies on the production of polarized e+e− pairs from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a high Z conversion target. The experiment was performed at the injector of the CEBAF accelerator at JLab and investigated the polarization transfer of an 8.3 MeV/c polarized electron beam to positrons produced in varying production target thicknesses. A dedicated new beam-line was constructed to produce, collect and transport positrons in the momentum range of 3.2 MeV/c to 6.2 MeV/c to a polarized iron target for polarization measurements. This technique potentially opens a new pathway for both high energy and thermal polarized positron beams. This presentation will discuss the PEPPo concept, the motivations for the experiment and the preliminary experimental results.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes. 		 
slides icon Slides WEOAB203 [4.102 MB]  
 
WEPWA021 X-ray Spectra Reconstruction with HOPG Crystal on TTX scattering, simulation, electron, laser 2174
 
  • Z. Zhang, Y.-C. Du, J.F. Hua, W.-H. Huang, C.-X. Tang, D. Wang, L.X. Yan
    TUB, Beijing, People's Republic of China
  
  Thomson Scattering sources, as the new generation of bright X-ray sources, have great application potential in many respects. Traditional spectra measurement methods, applied to measured the spectra of Thomson Scattering source, are troublesome as the X-ray beam is too intense to cause pile up problems. In this article, we use the HOPG crystal to reconstruct the X-ray spectra of Tsinghua Thomson X-ray source (TTX) through Braggs law. This method can get reasonable results with single or several shots, with high energy resolution. We also compare the experiment results of this method with the reconstructed spectra by analyzing the attenuation data of the X-ray beam in silicon , and these two results agree well with each other.  
 
WEPWA036 The Magnetic Performance of a Double Elliptically Polarized Undulator undulator, polarization, quadrupole, focusing 2208
 
  • Q.G. Zhou, H.F. Wang, M. Zhang, W. Zhang
    SINAP, Shanghai, People's Republic of China
  
  A pair of elliptically polarized undulators with APPLE-II type which will be used in a soft X-ray beam line for ARPES and PEEM at SSRF has been built and installed in the storage ring. The undulators can cover the energy range from 20eV to 2000eV of arbitrary polarized light including the horizontal, vertical, elliptical and circular polarization. The quasi-periodic design of the low energy undulator minimizes the contributions of the higher harmonics to be less than 20%. The magnet design and the measured magnetic field performance will be presented in this paper.  
 
WEPWA073 Compton Scattering Gamma-ray Light Source Modeling and Optimization electron, radiation, brightness, laser 2283
 
  • F.V. Hartemann, R.A. Marsh, S.S.Q. Wu
    LLNL, Livermore, California, USA
  
  Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
In Compton scattering light sources, a short (ps to ns) laser pulse and a high brightness relativistic electron beam collide to yield tunable, monochromatic, polarized gamma-ray photons. The properties of the gamma-ray phase space is studied, in relation to the full electron bunch and laser pulse phase spaces, along with collimation, nonlinear effects and other sources of spectral broadening. This process has potential high impact applications in homeland security, nuclear waste assay, medical imaging and stockpile surveillance, among other areas of interest. Detailed theoretical modeling is outlined to aid the design of Compton light sources and provide optimization strategies relevant within the context of nuclear photonics applications. 		 
 
WEPWA078 Compact Accelerator Design for a Compton Light Source cavity, electron, gun, emittance 2292
 
  • T. Satogata, K.E. Deitrick, J.R. Delayen, B.R.P. Gamage, K.G. Hernández-Chahín, C.S. Hopper, G.A. Krafft, R.G. Olave
    ODU, Norfolk, Virginia, USA
  • K.G. Hernández-Chahín
    DCI-UG, León, Mexico
  • G.A. Krafft, T. Satogata
    JLAB, Newport News, Virginia, USA
  
  Funding: Partially authored by Jefferson Science Associates, LLC under U.S. DOE contract NO. DE-AC05-06OR23177.
A compact electron accelerator suitable for Compton source applications is in design at the Center for Accelerator Science at Old Dominion University and Jefferson Lab. The design includes a KE=1.55 MeV low-emittance, optimized superconducting electron gun; a 23.45 MeV linac with multi-spoke 4.2 K superconducting cavities; and transport that combines magnetic longitudinal bunch compressor and transverse final focus. We report on the initial designs of each element, including end to end simulations with ASTRA and elegant, and expected beam parameters. 		 
 
WEPFI013 The Damped C-band RF Structures for the European ELI-NP Proposal damping, linac, beam-loading, dipole 2726
 
  • D. Alesini, R. Boni, R. D. Di Raddo, V.L. Lollo, B. Spataro, C. Vaccarezza
    INFN/LNF, Frascati (Roma), Italy
  • L. Ficcadenti, V. Pettinacci
    INFN-Roma, Roma, Italy
  • M. Migliorati, A. Mostacci, L. Palumbo
    URLS, Rome, Italy
  • L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  
  The gamma beam system of the European ELI-NP proposal foresees the use of a multi-bunch train colliding with a high intensity recirculated laser pulse. The linac energy booster is composed of 14 travelling wave C-Band structures, 1.8 m long with a field phase advance per cell of 2π/3 and a repetition rate of 100 Hz. Because of the multi-bunch operation, the structures have been designed with a damping of the HOM dipoles modes in order to avoid beam break-up (BBU). In the paper we discuss the design criteria of the structures also illustrating the effectiveness of the damping in the control of the BBU. Prototype activity is finally illustrated.  
 
WEPME021 Development of CO2 Laser Optical Enhancement Cavity for a Laser-Compton X-ray Source cavity, laser, scattering, polarization 2974
 
  • K. Ando, A. Endo, K. Sakaue, T. Takeichi, M. Washio
    Waseda University, Tokyo, Japan
  
  Funding: Work supported by NEDO (New Energy and Industrial Technology Development Organization).
We have been developing a laser-Compton X-ray source using optical enhancement cavity. We have studied 1um pulse laser storage in optical cavity and use for the experiments. Usage of 10um laser for optical enhancement cavity will increase the X-ray energy region of one laser-Compton X-ray source, so that we decided to develop the optical cavity for CO2 laser. We have designed external optical cavity for CO2 laser commercially available optics and verified the enhancement of CO2 laser in external optical cavity, and measured fundamental parameters such as finesse, matching efficiency, and enhancement factor. We have already achieved 540 of finesse, 43 of enhancement, and tested non-planer cavity, which storages two circular polarization separately. In this conference, we will report the design and experimental results of CO2 laser storage cavity and also some future prospects. 		 
 
WEPME038 Slow Orbit Feedback and Beam Stability at ALBA injection, wiggler, electron, feedback 3010
 
  • J. Marcos, M. Muñoz
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
  
  ALBA is a 3GeV 3rd generation synchrotron radiation source built nearby Barcelona providing service to users since May 2012. During all this period, a Slow Orbit Feedback system (SOFB) has been running during users’ operation in order to deliver a stable photon beam to the Beamlines. The system employs 88 out of the 104 Beam Position Monitors (BPMs) available at ALBA and 88 horizontal and vertical correctors. In addition, since the middle of the year (July 2012), the reading of the X-Ray BPM (XBPM) for one of the Front Ends, with a Bending Magnet as a source, has also been included in the correction loop. In this paper we summarize the performance of the SOFB system. Besides, we also present data corresponding to the evolution along the year of the XBPM readings for several Front Ends that have a planar Insertion Device (ID) as a source. The analyzed XBPMs are not included in the orbit correction loop, and consequently they supply information regarding the long term stability of ALBA Storage Ring.  
 
THPEA008 Study on the Energy Response of a Multi-layer Planar High Pressure Ionization Chamber using MCNP Program radiation, simulation, ion, electron 3164
 
  • Y.D. Ding, P.F. Wang, Q.B. Wang, Q.J. Zhang
    IHEP, Beijing, People's Republic of China
  
  High pressure ionization chamber is widely used to detect various radiation fields due to its good energy response. A new Multi-layer planar high pressure ionization chamber is designed suitable for measuring directional radiation field of high dose rate, because of its high electric field strength. In this paper, MCNP program is used to simulate and calculate the energy response of this ionization chamber to obtain the energy response of high energy photons, which could not be obtained by experimental methods. The results show that this ionization chamber can measure photon radiation energy up to 10MeV.  
 
THPFI070 Event Based System to Manage the Maintenance of Taiwan Photon Source status, controls, PLC, synchrotron 3460
 
  • C.W. Hsu, C.S. Chen, C.Y. Liu, Z.-D. Tsai
    NSRRC, Hsinchu, Taiwan
  
  This paper presents a model of event based maintenance management system to provide commission condition of utility facility. The system adopts cloud servers with structured query language (SQL) database to deal with all utility facility information. The system collects all event condition, including scheduled maintenance, troubleshooting, alert information and equipment specifications. The user can easily access all the facility information in mobile devices by scanning the quick response (QR) tag. The system can increase system reliability, decrease maintenance cost, minimize not programmed shutdowns and enhance system performance. Besides, the system can also provide enough information to schedule maintenance order by user or preventive and optimize energy usage.  
 
THPFI077 Construction Status of the TPS Vacuum Systems vacuum, ion, booster, storage-ring 3472
 
  • G.-Y. Hsiung, C.K. Chan, C.H. Chang, C.-C. Chang, S.W. Chang, Y.P. Chang, C.L. Chen, J.-R. Chen, Z.W. Chen, C.M. Cheng, Y.T. Cheng, S-N. Hsu, H.P. Hsueh, C.S. Huang, Y.T. Huang, T.Y. Lee, L.H. Wu, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
  • J.-R. Chen
    National Tsing Hua University, Hsinchu, Taiwan
  
  The vacuum systems for the 3 GeV Taiwan Photon Source (TPS) have been constructed since 2010. Most of the vacuum components and equipments have been manufactured and delivered. For the electron storage ring (SR), all the 24 cells of 14 m aluminum vacuum systems have been welded and assembled. The vacuum baking for the cells in the laboratory was undergoing to achieve the ultrahigh vacuum pressure below 1×10-8 Pa. The vacuum systems accommodated with the insertion devices in the long straight sections have been designed and under manufacturing. For the booster (BR), all the stainless steel chambers including the 0.7 mm elliptical chambers, BPM ducts, and the pumping chambers, have been manufactured. The two transport lines: LTB for Linac to BR and BTS for BR to SR were manufactured. Vacuum chambers for BTS adopt the similar chambers for BR but will be baked to ultrahigh vacuum for connecting with SR without injection window. The beam ducts for LTB will be made of aluminum alloys. The construction works for TPS vacuum systems will be completed before April of 2013 while the installation of the systems in the TPS tunnel will be started immediately.  
 
THPFI087 Measurements of Secondary Electron Yield of Metal Surfaces and Films with Exposure to a Realistic Accelerator Environment electron, vacuum, gun, background 3493
 
  • W. Hartung, J.V. Conway, C.A. Dennett, S. Greenwald, J.-S. Kim, Y. Li, T.P. Moore, V. Omanovic
    CLASSE, Ithaca, New York, USA
  
  One of the central goals of the CESR Test Accelerator program is to understand electron cloud (EC) effects in lepton rings and how to mitigate them. To this end, measurements of the secondary electron yield (SEY) of technical surfaces are being done in CESR. The CESR in-situ system, in operation since 2010, allows for measurements of SEY as a function of incident electron energy and angle on samples that are exposed to a realistic accelerator environment, typically 5.3 GeV electrons and positrons. The system was designed for periodic measurements to observe beam conditioning of the SEY and discrimination between exposure to direct photons from synchrotron radiation versus scattered photons and cloud electrons. Measurements so far have been done on bare metal surfaces (aluminum, copper, stainless steel) and EC-mitigatory coatings (titanium nitride, amorphous carbon, diamond-like carbon). A significant decrease in SEY with exposure to beam was observed for all cases other than the amorphous C samples; for the latter, the SEY remained near 1, independent of beam exposure. The SEY results are being used to improve predictive models for EC build-up and EC-induced beam effects.  
 
THPME011 Magnetic Field Design of the BAPS High Precision Quadrupole Magnet quadrupole, multipole, storage-ring, vacuum 3531
 
  • Y.S. Zhu, F.S. Chen, W. Kang, X.J. Sun
    IHEP, Beijing, People's Republic of China
  
  The Beijing Advanced Photon Source (BAPS) is a high performance light source planned to be constructed in China. High precision small aperture quadrupole magnets are required in the BAPS storage ring, which needs extremely high mechanical accuracy. Instead of the conventional manufacture method, the coils are comprised of several U-shaped solid copper sheets. So two-piece structure of the iron core can be adopted to reduce assembly error and improve the poles symmetry. Design considerations, 2D and 3D magnetic field calculations are presented in detail, and the needed mechanical precision is estimated according to the error field analysis.  
 
THPWA002 Optimization of the Photoneutron Flux Emitted by an Electron Accelerator for Neutron Interrogation Applications using MCNPX and TRIPOLI-4 Monte Carlo Codes target, electron, neutron, simulation 3630
 
  • A. Sari, F. Carrel
    CEA/DRT/LIST, Gif-sur-Yvette Cedex, France
  • C. Jouanne, A. Lyoussi, O. Petit
    CEA, Gif-sur-Yvette, France
  
  Various applications require neutron interrogation to detect special nuclear material. In a previous study*, we demonstrated the feasibility of this technique using the photoneutron flux emitted by a 16 MeV linear electron accelerator. This approach enables to reach average emission intensity on the order of one decade beyond the one produced by deuterium-tritium neutron generators traditionally used for such applications. Higher average emission intensities of the photoneutron flux would enable to expand boundaries of neutron interrogation. This new study aims at optimizing the photoneutron flux emitted by an electron accelerator. In order to ensure accuracy and reliability of our results, two Monte Carlo particle transport codes were used in parallel in this study: MCNPX developed by Los Alamos National Laboratory, and TRIPOLI-4 developed by the French Alternative Energies and Atomic Energy Commission. Potential discrepancies between results obtained with the two codes were investigated. Furthermore, careful attention was given to minimize the high-energy photon beam contained in the photoneutron flux in order to reduce spurious photofission reactions during measurements.
*A. Sari et al., IEEE Trans. Nucl. Sci., vol. 59, no.3, pp. 605-611, 2012. 		 
 
THPWA009 Generation of Laser Compton Scattered Gamma-rays from a 150-MeV Microtron laser, microtron, neutron, scattering 3645
 
  • R. Hajima, C.T. Angell, I. Daito, T. Hayakawa, M. Kando, T. Shizuma
    JAEA, Ibaraki-ken, Japan
  • H. Ohgaki
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  
  Funding: This work was supported in part by special coordination funds for promoting science and technology in Japan (Grant No. 066).
We have developed a laser Compton scattered gamma-ray source based on a 150-MeV racetrack microtron at Japan Atomic Energy Agency. The microtron equipped with a photocathode RF gun accelerates a single bunch of electrons to collide with a laser pulse from a Nd:YAG laser. We have employed laser pulse compression by stimulated Brillouin scattering to obtain high-flux gamma-rays, > 105 ph/s. The gamma-ray source is a prototype of commercial machine for nuclear security applications, non-destructive detection of nuclear material hidden in a ship cargo. Design and performance of the gamma-ray source are presented. 		 
 
THPWA014 Development of Photon-induced Positron Annihilation Lifetime Spectroscopy using an S-band Compact Electron Linac positron, electron, linac, laser 3660
 
  • Y. Taira, R. Kuroda, B.E. O'Rourke, N. Oshima, R. Suzuki, M. Tanaka, H. Toyokawa
    AIST, Tsukuba, Ibaraki, Japan
  • K. Watanabe
    Nagoya University, Nagoya, Japan
  • T. Yanagida
    Kyushu Institute of Technology, Fukuoka, Japan
  
  Funding: This work was supported by Grants-in-Aid for Scientific Research (22360297)
Positron annihilation lifetime spectroscopy (PALS) is a very sensitive tool to characterize materials and study defects at the nanometer scale. However, the application of PALS has been restricted to thin samples because of the limited range of positrons in materials. PALS for thick samples is possible by using high energy photons to create positrons inside the sample via pair production. This technique is called photon-induced positron annihilation lifetime spectroscopy (PiPALS). We have developed a novel PiPALS system using ultra-short photon pulses based on bremsstrahlung radiation to carry out in-situ measurement of structural materials under special conditions (piping for supercritical water and nuclear reactor materials). Intense, ultra-short photon pulses with energies up to 40 MeV can be generated by using an electron linear accelerator with photocathode rf gun system at AIST. In this conference, we will present the experimental result of the positron annihilation lifetime spectrum of a metal target by using ultra-short photon pulses*.
*Y. Taira et al., Rad. Phys. and Chem., accepted for publication 2012. 		 
 
THPWA016 Design and Optimization of the Target in Electron Linear Accelerator target, electron, simulation, radiation 3663
 
  • Q. Gao, H.B. Chen, J. Shi, H. Zha
    TUB, Beijing, People's Republic of China
  
  The target in electron linear accelerator plays an important role in the production of photon. Different materials and thickness of target have influence on dose rate. For 6MeV electron beam, this study gives the thickness of target for several materials in which the dose rate can be higher and drain electron can be lower. Then a X-ray target had been designed for 6MeV electron linac by FLUKA simulations. It can deliver 1000 cGy/min at 1 meter in front of the target if providing 6 MeV electron beam with 100uA current, which can achieve high-dose rate radiotherapy.  
 
THPWA028 Analysis of Uncertainty of Dose Rate Measurement on the Accelerator “QiangGuang-I” radiation, factory, electron, target 3684
 
  • R.B. Li, X.Y. Bai, X.M. Jin, Q. Ma, C. Qi, G.Z. Wang
    NINT, Xi'an, People's Republic of China
  
  “QiangGuang-I”, working on short pulse state, can be used to research the transient radiation effects on electronic devices. The measurement of dose rate is significant for assessing devices’ radiation-resistant ability. This paper comprehensively analyzes the originations of uncertainty on dose rate’s measurement, such as thermoluminescent dosemeter’s linearity degree and response to X-rays energy spectrum, testing instruments’ resolution, waveforms’ transmission distortion , and positional error; figures out the extended uncertainty. The result shows that the expanded uncertainty of dose rate’s measurement is less than 20%, which is satisfactory for researching on devices’ transient radiation effects, and proves that the method used to measure dose rate is reasonable.