IPAC2012 - List of Keywords (radiation)

Paper	Title	Other Keywords	Page
MOOBA03	Development of a High-power Coherent THz Sources and THz-TDS System on the basis of a Compact Electron Linac	electron, polarization, linac, laser	37
	M. Kumaki, K. Sakaue, M. Washio RISE, Tokyo, Japan R. Kuroda, H. Toyokawa, K. Yamada AIST, Tsukuba, Ibaraki, Japan
	The high-power terahertz time-domain spectroscopy (THz-TDS) has been developed on the basis of a compact S-band electron linac at AIST, Japan. It is strongly expected for inspection of dangerous materials in the homeland security field. The linac consists of a photocathode rf-gun, two acceleration tubes and a magnetic bunch compressor. The 40 MeV, 1 nC electron bunch is generated and compressed to less than 1 ps. THz radiations are generated in two methods with the ultra-short bunch. One is THz coherent synchrotron radiation (CSR). The other is THz coherent transition radiation (CTR). In the preliminary experiment, it was observed that the focused CTR had the donut profile in a transverse fields due to its initial radial polarization, so that it made Z-polarization. In case of the THz-TDS experiment, CTR was controlled to linearly polarization with the polarizer and focused to an EO crystal to obtain a THz temporal waveform which leads to THz spectrum with Fourier transform. The timing measurement between CTR and a probe laser was realized with OTR using a same optical photodiode. In this conference, we will describe details of our linac and results of the THz-TDS experiment.
	Slides MOOBA03 [3.342 MB]

MOOBB01	Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam	emittance, cavity, electron, simulation	49
	J.C.T. Thangaraj, H.T. Edwards, A.S. Johnson, A.H. Lumpkin, T.J. Maxwell, J. Ruan, J.K. Santucci, Y.-E. Sun, R.M. Thurman-Keup Fermilab, Batavia, USA
	Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.
	Slides MOOBB01 [2.338 MB]

MOOBB03	An Alternative 1D Model for CSR with Chamber Shielding	impedance, shielding, vacuum, synchrotron	52
	D. Zhou KEK, Ibaraki, Japan
	An alternative 1D model for modeling the longitudinal coherent synchrotron radiation (CSR) impedance is proposed. The code CSRZ* is used to calculate the CSR impedance with rectangular chamber shielding. Along the beam orbit, which may be formed by multi bends interleaved with drifts, the vacuum chamber is sliced into a series of segments. The low-frequency CSR impedance for each segment, in this case chamber shielding is significant, is obtained by numerical calculations. The high-frequency CSR impedance, in this case chamber shielding is negligible, is estimated by an analytical model*. The wake kick at each segment is computed via inverse Fourier transform of the impedance convolved the the beam spectrum. The most attractive merit of the method for CSR modeling lies in taking into account the realistic chamber shielding. D. Zhou, et al., To be published in Jpn. J. Appl. Phys. ** M. Borland, Phys. Rev. ST Accel. Beams 4, 070701 (2001).
	Slides MOOBB03 [1.856 MB]

MOEPPB013	Simulation and Measurement of Beam Loss in the Narrow-Gap Undulator Straight Section of the Advanced Photon Source Storage Ring	undulator, simulation, vacuum, neutron	106
	J.C. Dooling, M. Borland ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357. Simulations indicate the removal of a scraper/collimator in the Sector 37 straight section (SS) of the Advanced Photon Source storage ring (SR) results in increased beam loss in the remaining narrow-gap, insertion device SS, ID4. Modeling with elegant provides loss distributions in the 5-mm aperture vacuum chamber of ID4 and includes the effects of rf system muting and quantum excitation in the bunch. The loss distributions are then used as input to a MARS model of the SS that includes undulator geometry. ID4 has been instrumented with additional monitoring to capture beam loss events, particularly beam dumps. Cerenkov detectors and fiber-optic cable bundles are used to capture temporal profiles of beam loss events. Beam dumps deliver 2600 J to the vacuum chamber and surrounding hardware including undulators. Data indicate a variety of temporal profiles occur during the beam dumps, with the shortest lasting 6 microseconds, FWHM (<2 turns). Such high power and power densities can lead to physical damage of vacuum components if not handled correctly. Touschek scattering loss is also a concern for undulator demagnetization. Comparison of modeling and measurements will be presented.

MOPPC012	Reliability and Intervention Management for the LHC	controls, status, feedback, site	148
	K. Foraz, J.R. Cook, J. Coupard, B. Daudin, J. De Jonghe, F. B. Dos Santos Pedrosa, E.R. Fuentes, C. Garino, K. Golikov, S. Grillot, M.R. Jaekel, P. Sollander CERN, Geneva, Switzerland
	Since 2010, CERN has entered a mode of continuous operation of the LHC and its injectors, which implies the continuous operation of all the infrastructure and support systems. High reliability of the machines is crucial to meet the physics goals. This high reliability must be accompanied by a fast restart after programmed stops. Since 2010, an important effort has been put in place, to ease the coordination process during the programmed stops and to reinforce the management of the interventions (preparation, approval, follow-up, traceability, closure). This paper describes the difficulties from the first year related to this coordination, and the impact on operation. The tools developed for the management of the interventions, their assets and the effect on the reliability of the LHC will also be presented and discussed.

MOPPC052	Calculation of Synchrotron Radiation from High Intensity Electron Beam at eRHIC	photon, electron, synchrotron, vacuum	247
	Y.C. Jing, O.V. Chubar, V. Litvinenko BNL, Upton, Long Island, New York, USA
	The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab adds an electron beam line to the existing RHIC and improves the luminosity by at least 2 orders of magnitude. It requires a high energy and high intensity electron beam. Thus the synchrotron radiation (SR) coming from the bending magnets and large quadrupoles could be penetrating the vacuum chamber and providing hazard to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity and power density distributions on the chamber wall, suggest the wall thickness required to stop the SR, calculate heat load on the chamber, and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

MOPPC084	G4beamline Code Development	space-charge, electron, collider, synchrotron	334
	T.J. Roberts Muons, Inc, Batavia, USA
	Funding: Supported in part by DoE STTR grant DE-FG02-06ER86281. G4beamline is a single-particle-tracking simulation program based on Geant4, optimized specifically for beam lines. It is currently used by several hundred physicists and designers around the world, who apply it to a diverse set of interesting problems. As it includes particle decays and interactions, it is applicable to beams for which decays and interactions are important, such as modern muon facilities that involve ionization cooling. Its description language has been designed to be both versatile and user-friendly, and the program includes high-quality visualization and histogramming capabilities. This paper discusses recent code development and new features, and some interesting applications of the program. G4beamline is an open-source program freely available at http://g4beamline.muonsinc.com

MOPPC090	Coupling Modulator Simulations into an FEL Amplifier for Coherent Electron Cooling	FEL, electron, simulation, positron	346
	I.V. Pogorelov, G.I. Bell, D.L. Bruhwiler, B.T. Schwartz, S.D. Webb Tech-X, Boulder, Colorado, USA Y. Hao, V. Litvinenko, G. Wang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US DOE Office of Science, Office of Nuclear Physics under grant numbers DE-FG02-08ER85182 and DE-SC0000835. Next-generation ion colliders will require effective cooling of high-energy hadron beams. Coherent electron cooling (CeC) can in principle cool relativistic hadron beams on orders-of-magnitude shorter time scales than other techniques. Particle-in-cell (PIC) simulations of a CeC modulator with the parallel VORPAL framework generate macro-particle distributions with subtle but important phase space correlations. To couple these macro-particles into a 3D simulation code for the free-electron laser (FEL) amplifier, while retaining all details of the 6D phase space coordinates, we implemented an alternative approach based on particle-clone pairs. Our approach allows for self-consistent treatment of shot noise and spontaneous radiation, with no need for quiet-start initialization of the FEL macro-particles' ponderomotive phase. We present results of comparing fully 3D amplifier modeling based on the particle-clone approach vs GENESIS simulations where distribution of bunching parameter was used as input. We also discuss enabling direct coupling of the VORPAL delta-f simulation output into 3D distributions of particle-clone pairs. V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009). ** V.N. Litvinenko, "Macro-particle FEL model with self-consistent spontaneous radiation," unpublished (2002).

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

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

MOPPD083	Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels	booster, kicker, injection, beam-losses	562
	I.L. Rakhno, A.I. Drozhdin, N.V. Mokhov, V.I. Sidorov, I.S. Tropin Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. Currently a fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-5 straight section is used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With magnetic field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using two horizontal kickers in the Long-12 section. The STRUCT calculations show that using such horizontal notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV, directing 96% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. The MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.

MOPPP003	Comparison of Various Sources of Coherent THz Radiation at FLUTE	electron, synchrotron, linac, synchrotron-radiation	568
	M. Schwarz, E. Huttel, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, M. Schuh, P. Wesolowski KIT, Karlsruhe, Germany M.T. Schmelling MPI-K, Heidelberg, Germany
	The "Ferninfrarot Linac- Und Test-Experiment" FLUTE, based on a 50 MeV S-band linac with bunch compressor, is currently under construction at the KIT in Karlsruhe in order to study the production of coherent radiation in the Terahertz frequency range. The three photon generating mechanisms investigated in this paper are coherent synchrotron-, edge-, and transition radiation. For each case, we present the spectra and peak electric fields calculated from longitudinal charge distributions of a short, low charge and a long, high charge bunch. The respective bunch shapes are obtained by a detailed simulation (particle tracking) of FLUTE. We also give the expected temporal evolution of the electric field pulses.

MOPPP005	Feasibility of THz Source Based on Coherent Smith-Purcell Radiation Generated by Femtosecond Electron Bunches in Super-Radiant Regime	electron, simulation, laser, gun	574
	L.G. Sukhikh, K.P. Artyomov, A. Potylitsyn Tomsk Polytechnic University, Tomsk, Russia A.S. Aryshev, J. Urakawa KEK, Ibaraki, Japan V. Karataev JAI, Egham, Surrey, United Kingdom
	Nowadays there is a big interest to THz radiation that is a promising tool for investigations in material science, in biology, medicine and other fields. THz radiation for users is mostly produced by Light Sources that are big and complex machines. Because of this there are numerous activities in research and development of a compact THz source. One of the trends is based on using different types of radiation generated in coherent regime by short electron bunches. The promising radiation mechanism is coherent Smith-Purcell radiation (CSPR) that has monochromatic angular distribution and that is generated while the bunch travels in a vicinity of a grating. In this report we present simulated characteristics of frequency-locked coherent Smith-Purcell radiation (super-radiant regime) generated by a train of short (hundreds of femtosecond) 10 MeV electron bunches with THz spacing. The simulations are performed for different grating profiles and parameters using existing CSPR models and Particle-in-Cell simulation code. We also discuss the feasibility of the THz source based on CSPR and status of the experiment that is prepared at LUCX facility at KEK after the upgrade.

MOPPP006	Inverse Cherenkov Radiation based on Smith-Purcell Effect	electron, linac, gun, laser	577
	K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan M. Hangyo ILE Osaka, Suita, Japan R. Kuroda, H. Toyokawa AIST, Tsukuba, Ibaraki, Japan
	Inverse Cherenkov radiation based on Smith-Purcell effect using metamaterial was investigated. A metallic grating and picosecond electron bunch of 27 MeV beam energy from a thermionic DC gun and linac were used for the inverse radiation. The frequency spectra in terahertz (THz) range were measured by a Michelson interferometer experimentally. Peaks of discrete component in the spectra shifted continuously according to the radiation angles, e. g. discrete peak changing from 0.117 to 0.085 THz with radiation angle along the electron bunch from 102 to 134 degree (backward) using a 2-mm-period metallic grating. In this presentation, experiment using another electron bunch generated by a photocathode RF gun linac will be reported.

MOPPP007	High-intensity Monochromatic Cherenkov Radiation in THz Range by Femtosecond Electron Bunches in Impurity-doped Semiconductor Tube	electron, plasma, wakefield, vacuum	580
	A. Ogata, K. Kan, T. Kondoh, K. Norizawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	A novel method to generate high-power THz radiation is proposed and the preliminary experiments are conducted. If a beam with a bunch length on the order of 100 fs is injected into an electron–hole plasma of a semiconductor with a plasma frequency on the order of THz, THz wake fields are coherently generated. If the beam moves on the axis of a hollow tube covered by a metal, the frequency spectrum of the radiation is composed of discrete components. Monochromatic radiation is obtained by making only the lowest frequency component coherent. In the preliminary experiments using mm-sized dielectric tubes, the radiation spectra, which was driven by electron bunches of 200fs/27 MeV, were measured directly by a Michelson interferometer and bolometer. Peaks at frequencies of 0.09 and 0.14 THz of transverse magnetic (TM) modes, which corresponded to TM03 and TM04, were observed. The other higher modes, e. g. 0.36 (TM09) and 0.40 THz (TM010), were also observed successfully at a bunch charge of 15 pC, which decreased the electron bunch length.

MOPPP010	Investigation of CSR Effect for Femtosecond Electron Bunches in an Isochronous Accumulator Ring	simulation, lattice, electron, linac	589
	N.Y. Huang, H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, K. Takahashi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Coherent synchrotron radiation (CSR) from a novel isochronous ring is a candidate for light source that provides THz radiation with high average flux. A compact isochronous accumulator ring (IAR) for the maximum beam energy of 54 MeV has been designed so as to eliminate the 0th order momentum compaction factor, and the 1st order of it is mostly compensated. In addition, the path length deviation due to betatron motion is mostly compensated in a cell. Though there is no RF cavity in IAR, the injected beam may circulate for certain number of turns. Multi experimental stations can be allocated like synchrotron radiation facilities. However, it has been well known that instability due to the CSR wake field is an issue for the beam stability in the ring operated at low alpha mode. Therefore, a study for effects of the CSR wake on the bunch length and shape in IAR has been in progress. It has turned out that the maximum longitudinal field strength created by CSR would be ~ 0.15 MV/m for the case of 100 fs Gaussian bunch, which is considerably an intense field. To protect the bunch shape from the CSR wake, further study is definitely required.

MOPPP012	Experimental Observation of Energy Modulation in Electron Beams Passing through Terahertz Dielectric Wakefield Structures	wakefield, bunching, FEL, acceleration	595
	S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York, USA W. Gai, A. Zholents ANL, Argonne, USA B.C. Jiang SINAP, Shanghai, People's Republic of China
	Funding: DOE SBIR. We report observation of a strong wakefield induced energy modulation in an energy-chirped electron bunch passing through a terahertz dielectric-lined waveguide. This modulation can be effectively converted into a spatial modulation by means of a chicane, forming micro-bunches (density modulation) with a periodicity of 0.5 - 1 picosecond, hence capable of driving coherent THz radiation. The experimental results agree well with theoretical predictions.

MOPPP018	Construction Status of the Compact ERL	linac, cryomodule, gun, emittance	607
	S. Sakanaka, H. Kawata, Y. Kobayashi, N. Nakamura KEK, Ibaraki, Japan R. Hajima JAEA, Ibaraki-ken, Japan
	Future synchrotron light source based on a 3-GeV energy recovery linac (ERL) is under proposal at KEK, and we are conducting extensive R&D efforts. To demonstrate reliable operations of key components for the ERL project, as well as to demonstrate the generation of ultra-low emittance beams, we are constructing the Compact ERL (cERL). The cERL will also be used to demonstrate the generation of brilliant gamma-rays that is useful for analyzing radioisotopes. Key components, such as a photocathode DC gun, both cryomodules for the injector and the main linac, rf sources, magnets, and beam instrumentations, are under fabrication. Construction of radiation shielding for the cERL started in December, 2011. We report up-to-date status of the cERL.

MOPPP022	ALICE: Status, Developments and Scientific Programme	FEL, gun, acceleration, cryomodule	613
	Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	ALICE (Accelerators and Lasers In Combined Experiments) is a multifunctional ERL based R&D facility that operates in various regimes, both energy recovery and non energy recovery, depending on the project undertaken (beam energy 10-28MeV, bunch charge 20-100pC, train length from a single bunch to 100us). In early 2012, the DC HV photoinjector gun is expected to begin operation at nominal 350kV and a new cryomodule, a result of a wide international collaboration, will be installed and commissioned on ALICE. The improvements in beam dynamics and the overall beam quality will be discussed in this paper. The overview of the ALICE scientific programme including IR-FEL lasing and its application for scanning near field optical microscopy, generation and applications of coherent broadband THz radiation for life sciences and solid state physics, studies of the first non-scaling FFAG EMMA for which ALICE serves as an injector and accelerator physics research will also be presented.

MOPPP032	Longitudinal Phase Space Studies at the PITZ Facility	electron, laser, gun, FEL	631
	M. Mahgoub, J.W. Bähr, H.-J. Grabosch, M. Groß, L. Hakobyan, G. Klemz, G. Kourkafas, M. Krasilnikov, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, K. Rosbach, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany I.I. Isaev MEPhI, Moscow, Russia Ye. Ivanisenko IERT, Kharkov, Ukraine M. Khojoyan ANSL, Yerevan, Armenia J. Li USTC/NSRL, Hefei, Anhui, People's Republic of China B. Marchetti INFN-Roma II, Roma, Italy D. Richter HZB, Berlin, Germany J. Rönsch-Schulenburg Uni HH, Hamburg, Germany
	Photoinjectors are a cornerstone for short-wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL in Hamburg, Germany. The Photo Injector Test facility at DESY, location Zeuthen (PITZ), was built to develop and optimize such photoinjectors. The PITZ facility is capable of generating long trains of electron bunches, which can be accelerated up to ~25 MeV/c. Studying and optimizing the longitudinal properties of the electron bunch is an important topic at PITZ. A streak system consisting of Silica Aerogel radiators, optical transition radiation (OTR) screens, optical transmission line, and a streak camera is used to study the longitudinal properties with an accuracy of some ps. Due to the high radiation level in the facility, many of the lenses in the optical transmission line have turned brown, reducing the efficiency of the system. Some of the lenses were recovered by baking them up to 180°C. In contrast, few sensitive objective lenses can not be baked, rather they were recovered via exposure to infrared radiation with the proper wave length. An overview of the system, the difficulties, and the modifications needed to overcome the radiation effects are presented.

MOPPP072	Performance of APPLE-II Type Quasi-Periodic Undulator at HiSOR	undulator, polarization, electron, photon	729
	S. Sasaki, M. Arita, K. Goto, A. Miyamoto, T. Okuda HSRC, Higashi-Hiroshima, Japan
	A 1.8-m-long 78-mm-period quasi-periodic APLPE-II undulator was installed in the 700-MeV HiSOR storage ring of Hiroshima Synchrotron Radiation Center. At 23-mm nominal minimum gap, the fundamental photon energies are 3.1 eV, 6.5 eV, and 4.8 eV for horizontal linear, vertical linear, and circular polarization, respectively. The photon energies of observed fundamental and higher harmonic radiations are in good agreement with those of model calculations using measured undulator field and the HiSOR beam parameters. Also, observed flux thorough a slit and a grating monochromator was more than twice larger than that from previously installed 100-mm-period helical undulator for the whole range of radiation spectra. The feedforward COD correction was done to avoid the intensity fluctuation of photon beam in other BM beamlines due to the gap and phase motion of undulator. No fatal effect on the stored electron beam by installing the undulator was observed though a slight beam size change was observed at the minimum gap.

MOPPP074	Magnetic Field Measurement for a THz Undulator Using the Vibrating Wire Method	undulator, electron, laser, resonance	732
	S. Kashiwagi, H. Hama, F. Hinode, M. Kawai, X. Li, T. Muto, K. Nanbu, Y. Tanaka Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Funding: This work is supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (S), Contract #20226003. We constructed the undulator that is a basically a Halbach planer type for a generation of intense coherent terahertz radiation from the very short electron bunch. The period length of the undulator and the number of periods are 100 mm and 25, respectively. Its maximum magnetic field is 0.41 T and the K-value is 3.82 with 54 mm gap. The vibrating wire method is studied to measure the periodic magnetic field of the undulator. By measuring amplitudes and phases of standing waves excited on the wire by the Lorentz force between AC current and magnetic field, we can reconstruct the magnetic field distribution along the wire. The theoretical analysis has been performed for the THz undulator and derived a relation between a reproducibility of undulator field and the number of the harmonic mode to use for the reconstruction. A model experiment was demonstrated using 20cm wire and one pair of permanent magnet block. The theoretical study and the results of model experiment using the vibrating wire method will be shown in this conference.

MOPPP075	The Research on Magnetic Properties of Magnet for SSRF Cryogenic Permanent Magnet Undulator	cryogenics, undulator, permanent-magnet, synchrotron	735
	Y.Z. He, L. Wang, Q.G. Zhou SINAP, Shanghai, People's Republic of China
	The temperature coefficient of Br and Hci of Nd2Fe14B and Pr2Fe14B permanent magnet are about -0.1 K-1 and -0.6 K-1 respectively, the higher Br and Hci can be obtained at low temperature. By this theory, a cryogenic permanent magnet undulator(CPMU) may be designed, the maximum magnetic field and the Hci of permanent magnet increased 10-50% and 300-500% respectively, compared with the conventional undulators, the higher brightness X-rays and the more resistance to radiation of undulators can be obtained. The Pr2Fe14B permanent magnet has better potential magnetic properties than the Nd2Fe14B permanent magnet at low temperature for having no spin reorientation phenomenon. The permanent magnets are key “heart” magnetic components for cryogenic permanent magnet undulator, since January 2012, the research plan on magnetic properties of domestic permanent magnet for SSRF cryogenic permanent magnet undulator at low temperature by the support of Shanghai and Nation Nature science funds be started, the paper introduced research status of the item.

MOPPP076	Design Considerations for a Hybrid Undulator Applied in a Terahertz FEL Oscillator	undulator, FEL, electron, cavity	738
	B. Qin, M. Fan, Y.Q. Xiong Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China Y.J. Pei USTC/NSRL, Hefei, Anhui, People's Republic of China P. Tan HUST, Wuhan, People's Republic of China
	A planer undulator using hybrid permanent magnet scheme was designed for a FEL based 1THz~3THz radiation source. The influence of the undulator magnetic field errors, including peak field shift and field integrals errors, on the coherent radiation performance such as the gain per pass is investigated. And finally specifications of the undulator are determined.

MOPPP077	Heat Load Budget on TPS Undulator in Vacuum	undulator, synchrotron, synchrotron-radiation, vacuum	741
	J.C. Huang, J. Chen, C.-S. Hwang, F.-Y. Lin, Y.T. Yu NSRRC, Hsinchu, Taiwan
	The performance of an insertion device is limited by the magnet gap because a small gap affects the dynamic aperture and results in a short life time of the beam. An in-vacuum undulator is designed to have no vacuum chamber between the magnet arrays so to allow the entire magnet gap to be fully used for the dynamic aperture. An in-vacuum undulator can optimally minimize the gap to achieve continuous energy spectra. One problem of an undulator with a small gap is resistive wall heating by the image current. The heat load depends strongly on the injected mode in the storage ring; injection of multiple bunches might deteriorate the thermal performance for the magnet array. In this paper, we present a calculation of the heat load budget for a magnet array of an in-vacuum undulator of Taiwan Photon Source (TPS).

MOPPP078	Status of the First Planar Superconducting Undulator for the Advanced Photon Source	undulator, photon, controls, status	744
	Y. Ivanyushenkov, M. Abliz, K.D. Boerste, T.W. Buffington, C.L. Doose, J.D. Fuerst, Q.B. Hasse, M. Kasa, S.H. Kim, R. Kustom, E.R. Moog, D. Skiadopoulos, E. Trakhtenberg, I. Vasserman ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Superconducting technology offers the possibility of building short-period undulators for synchrotron light sources. Such undulators will deliver higher fluxes at higher photon energies to the light source user community. The Advanced Photon Source (APS) team is building the first superconducting planar undulator to be installed in the APS storage ring. The current status of the project is presented in this paper.

MOPPP085	Single Electron Dynamic of Microwave Undulator	electron, undulator, FEL, free-electron-laser	753
	C. Chang, J. Neilson, C. Pellegrini, M. Shumail, S.G. Tantawi SLAC, Menlo Park, California, USA
	The analytical and numerical calculations for the dynamic of single electron and beam in RF undulator have been conducted and compared. The transverse and longitudinal velocity, trajectory, energy variation, and the spontaneous radiation are studied. It is found that the forward and backward wave (FW/BW) components have different contribution on electron motion and radiation, most of the energy spread comes from FW component, in other words, the effect of FW on modulating the electron energy is much stronger than that of BW for the same undulating-amplitude value, which mechanism has been analyzed.

MOPPP090	Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings	undulator, electron, vacuum, photon	765
	O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe BNL, Upton, Long Island, New York, USA J.A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: US DOE, Contract No. DE-AC02-98CH10886. We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations.

MOPPP091	Recent Developments at the DELTA THz Beamline	laser, electron, storage-ring, undulator	768
	P. Ungelenk, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, A. Schick, M. Zeinalzadeh DELTA, Dortmund, Germany
	Funding: Work supported by DFG, BMBF, and by the Federal State NRW. During 2011, a new dedicated THz beamline has been constructed and commissioned at DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University. This beamline enables extracting and detecting coherent THz pulses caused by a laser-induced density modulation of the electron bunches. Ongoing experiments aim at characterizing the THz radiation as well as investigating the evolution of the density modulation over subsequent revolutions following the initial laser-electron interaction in an undulator.

MOPPR011	A New Diagnostic Beamline at ELSA	synchrotron, synchrotron-radiation, diagnostics, electron	795
	S. Zander, F. Frommberger, P. Hänisch, W. Hillert, B. Neff ELSA, Bonn, Germany
	Funding: Funded by the DFG within the SFB / TR 16. At the Electron Stretcher Facility (ELSA), a new synchrotron light diagnostic Beamline has been installed in order to perform high resolution, transversal and longitudinal beam profile measurements by analyzing the emitted synchrotron light. For this purpose, the main deflecting AL mirror selects a wide range of wavelengths from 200–800 nm out of the whole synchrotron spectrum. The setup of the beamline and its relevant components will be presented.

MOPPR014	Installation and Test of a Beam Loss Monitor System for the S-DALINAC	electron, controls, monitoring, background	804
	R. Stegmann, U. Bonnes, C. Burandt, R. Eichhorn, F. Hug, L.E. Jürgensen, N. Pietralla TU Darmstadt, Darmstadt, Germany D. Proft ELSA, Bonn, Germany
	Funding: This work is supported by the DFG through SFB 634. The superconducting Darmstadt linear accelarator S-DALINAC is designed for accelerating electrons up to energies of 130 MeV for measurements in nuclear physics at small momentum transfers. For the purpose of machine protection and in order to increase reliability and efficiency an efficient tool for on-line measurements of beam losses down to electron energies of 1 MeV is desirable. Therefore a system of beam-loss monitors has been developed, installed, and tested. The system consists of commercially availiable PIN-diods and newly developed electronics. Implementation in the S-DALINAC's control system is done via EPICS IOC. We will report on the setup of the beam-loss monitoring system and on its initial performance in first tests.

MOPPR019	Beam Profile Imaging Based on Backward Transition Radiation in the Extreme Ultraviolet Region	electron, target, FEL, diagnostics	819
	L.G. Sukhikh, S. Bajt, G. Kube DESY, Hamburg, Germany W. Lauth IKP, Mainz, Germany Yu.A. Popov, A. Potylitsyn Tomsk Polytechnic University, Tomsk, Russia
	Backward transition radiation (BTR) in the optical spectral region is widely used for beam profile diagnostics in modern electron linacs. However, the experience from linac based light sources shows that BTR diagnostics might fail because of coherence effects in the emission process. To overcome this problem of coherent emission it was proposed to use BTR in the extreme ultraviolet (EUV) region, and measurements of the angular EUV BTR distribution were presented in Ref. . This contribution summarizes the results of a beam profile imaging experiment using EUV BTR. The experiment was carried out using the 855 MeV electron beam of the Mainz Microtron MAMI. EUV BTR was generated at a molybdenum target deposited onto a silicon substrate, and imaging was realized using a spherical multilayer mirror which was optimized for a wavelength of 19 nm. Preliminary results will be presented and compared to ordinary optical BTR imaging together with a discussion of future possibilities of the proposed diagnostic method. L.G. Sukhikh et al., Nucl. Instrum. Methods A623, 567 (2010). ** L.G. Sukhikh et al., Proc. of DIPAC-2011, Hamburg (Germany), 544 (2011).

MOPPR024	Non-intercepting Emittance Measurements by means of Optical Diffraction Radiation Interference for High Brightness Electron Beam	quadrupole, electron, emittance, target	831
	A. Cianchi Università di Roma II Tor Vergata, Roma, Italy V. Balandin, N. Golubeva, K. Honkavaara, G. Kube DESY, Hamburg, Germany M. Castellano, E. Chiadroni INFN/LNF, Frascati (Roma), Italy L. Catani INFN-Roma II, Roma, Italy
	Conventional intercepting transverse electron beam diagnostics, e.g. based on Optical Transition Radiation (OTR), cannot tolerate high power beams without remarkable mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR) is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitations of this method is the low signal to noise ratio, mainly due to the unavoidable synchrotron radiation background. This problem can be overcome by using ODRI (Optical Diffraction Radiation Interference). In this case the beam goes through two slits opened on metallic foils, placed in a distance shorter than the radiation formation zone. Thanks to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. Here we report the first measurements, carried out at FLASH (DESY, Germany), of the beam emittance using ODRI. Our results demonstrate the unique potential of this technique.

MOPPR050	Design and Analysis of EPU XBPM in TPS	undulator, photon, synchrotron, synchrotron-radiation	894
	A. Sheng, C.M. Cheng, C.K. Kuan NSRRC, Hsinchu, Taiwan D. Shu ANL, Argonne, USA
	Several planer and elliptical polarized undulators (EPU) beam lines have been proposed and are to be built for Taiwan Photon Source (TPS) in National Synchrotron Research Center (NSRRC). Due to its complexity, with changing of vertical as well as horizontal deflection parameters (Kx and Ky), one finds that regular diamond bladed photon beam position monitor (XBPM) would not be sufficient to detect the center location of the undulator. A new conceptual design of EPU XBPM has been analyzed both in thermal as well as photon aspects. A prototype by taking advantage of fluorescent some of the diamond detectors has been designed and implemented in Taiwan Light Source (TLS) for testing. Some analysis and design scenarios are presented in this paper.

MOPPR054	Beam Size Measurement at Siam Photon Source Storage Ring	synchrotron, storage-ring, monitoring, photon	906
	P. Sudmuang, N. Deethae, P. Klysubun, S. Krainara, T. Poolampong, K. Sitisart, N. Suradet SLRI, Nakhon Ratchasima, Thailand
	Synchrotron radiation interferometer and direct imaging setups have been installed and subsequently utilized to investigate transverse beam profile at the Siam Photon Source (SPS). Details of the optical setup as well as the beam sizes determined from the measurement will be presented. Comparison between the measured and theoretical values as established by linear optics calibration will be made and discussed. In order to demonstrate the beam profiling capability of the interferometer and direct imaging systems, measurements with different operating parameters have been carried out and the results will be presented as well.

MOPPR063	Exploiting the Undesired: Beam-gas Interactions in the LHC	vacuum, simulation, proton, quadrupole	927
	R. Versaci, V. Baglin, M. Brugger CERN, Geneva, Switzerland A. Mereghetti UMAN, Manchester, United Kingdom
	The vacuum inside the LHC pipes has a key role in correct operation of the accelerator. The interaction of the beam with residual gas in the pipes can lead to the loss of the beam itself and damage accelerator components. Nevertheless, beam-gas interactions can be exploited to indirectly measure the gas pressure inside the beam pipe, detecting the secondaries produced. The showers generated are detected by Beam Loss Monitors, whose signals depend on the gas pressure. This technique would also allow to punctually measure the gas pressure in sections of the accelerator where vacuum gauges are not frequent, such as the arcs. The problem has been addressed by means of FLUKA simulations and the results have been benchmarked with direct measurements performed in the LHC in 2011.

MOPPR071	Initial Results of Transverse Beam Profile Measurements Using a LYSO:Ce Crystal	diagnostics, electron, controls, laser	951
	A.S. Johnson, A.H. Lumpkin, T.J. Maxwell, J. Ruan, J.K. Santucci, C.C. Tan, R.M. Thurman-Keup, M. Wendt Fermilab, Batavia, USA
	A prototype transverse beam profile monitor for eventual use at the Advanced Superconducting Test Accelerator (ASTA) has been tested at the Fermilab A0 Photoinjector. Results from low-charge (20 pC) studies indicate that a LYSO:Ce scintillator will be a viable replacement for a YAG:Ce scintillator when using intercepting radiation convertor screens for beam profiling. We will also describe the planned implementation of LYSO:Ce crystals to mitigate the coherent optical transition radiation due to the microbunching instability through the use of band-pass filters and specially timed cameras.

MOPPR077	ION CHAMBERS AND HALO RINGS FOR LOSS DETECTION AT FRIB	ion, linac, cryomodule, simulation	969
	Z. Liu IUCF, Bloomington, Indiana, USA D. Georgobiani, M.J. Johnson, M. Leitner, R.M. Ronningen, T. Russo, M. Shuptar, R.C. Webber, J. Wei, X. Wu, Y. Yamazaki, Y. Zhang, Q. Zhao FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. Unlike the high energy proton machines, our radiation transport simulation results show that it will be difficult to use traditional BLMs to detect beam losses for FRIB linac, not only due to the low radiation levels from low energy heavy ion beams, but also resulted by the cross talk effect from one part of the machine to another in the folded machine geometry. A device called “Halo Ring” is introduced as a component of the BLM system to substitute the traditional ion chamber in those regions.

MOPPR090	Progress Report on Development of a High Resolution Transverse Diagnostic based on Fiber Optics	electron, diagnostics, photon, optics	996
	R. Tikhoplav, R.B. Agustsson, G. Andonian, A.Y. Murokh, S. Wu RadiaBeam, Santa Monica, USA R.K. Li, P. Musumeci, C.M. Scoby UCLA, Los Angeles, California, USA
	A beam profile monitor utilizing the technological advances in fiber optic manufacturing to obtain micron level resolution is under development at RadiaBeam Technologies. This fiber-optic profiling device would provide a low cost, turn-key solution with nominal operational supervision and requires minimal beamline real estate. Preliminary results of Cherenkov light generation in fiber is presented.

TUOAB02	Investigation of the Use of Silicon, Diamond and Liquid Helium Detectors for Beam Loss Measurements at 2 Kelvin	cryogenics, proton, electron, interaction-region	1080
	C. Kurfuerst, B. Dehning, W.T. Eisel, M. Sapinski CERN, Geneva, Switzerland V. Eremin IOFFE, St. Petersburg, Russia C. Fabjan HEPHY, Wien, Austria
	At the triplet magnets, close to the interaction regions of the LHC, the current Beam Loss Monitoring (BLM) system is very sensitive to the debris from the collisions. For future beams with higher energy and higher luminosity this will lead to a situation in which the BLM system can no longer distinguish between these interaction products and quench-provoking beam losses from the primary proton beams. The solution investigated is to locate the detectors as close as possible to the superconducting coil, i.e. the element to be protected. This means putting detectors inside the cold mass of the superconducting magnets at 1.9 K. As possible candidates for such loss monitors, diamond, silicon and a liquid helium chamber have been tested in a proton beam at liquid helium temperatures. The initial promising results from these tests will be presented and discussed in this contribution.
	Slides TUOAB02 [3.412 MB]

TUOBB03	Status of the FERMI@Elettra Project	FEL, laser, electron, photon	1092
	M. Svandrlik, E. Allaria, L. Badano, S. Bassanese, F. Bencivenga, E. Busetto, C. Callegari, F. Capotondi, D. Castronovo, M. Coreno, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, A.A. Demidovich, M. Di Fraia, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, P. Furlan Radivo, G. Gaio, L. Giannessi, R. Gobessi, C. Grazioli, E. Karantzoulis, M. Kiskinova, M. Lonza, B. Mahieu, C. Masciovecchio, S. Noè, F. Parmigiani, G. Penco, E. Principi, F. Rossi, L. Rumiz, C. Scafuri, S. Spampinati, C. Spezzani, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, M. Zaccaria, D. Zangrando, M. Zangrando ELETTRA, Basovizza, Italy
	Funding: The work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3. The FERMI@Elettra seeded Free Electron Laser has provided the first photons to the experimental stations during 2011. The first FEL line in operation is FEL-1, covering the wavelength range between 100 nm and 20 nm. The facility will be opened to users by the end of 2012. In the meantime the installation of the second FEL line, FEL-2 covering the higher energy range down to 4 nm, is progressing on schedule and first tests have started. A description of the status of the project is presented here.
	Slides TUOBB03 [5.316 MB]

TUEPPB009	First Measurements of the FACET Coherent Terahertz Radiation Source	electron, diagnostics, photon, insertion	1134
	Z. Wu, E. Adli, A.S. Fisher, M.J. Hogan, H. Loos SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. The Facility for Accelerator science and Experimental Tests (FACET) at SLAC provides a high peak current, sub-ps bunched beam that is ideal for THz photon generation via coherent transition radiation. This paper presents preliminary characterization of the THz pulses generated by FACET electron beam. A one-micron thick Ti foil has been inserted into the beam path and the radiated photons collected. Michelson spectroscopy yields frequency content spanning from 0.25 THz to 2.3 THz and peaked at around 0.5 THz. Multiple scans at different bunch compression show a monotonic increase of the peak radiation frequency as the electron bunch gets shorter. Using the Kramers-Kronig relation, the temporal profile of the THz pulse is reconstructed from the power spectrum indicating a ~4 picosecond main pulse followed by a long oscillating tail due to the water absorption lines and detector response. Knife-edge scans measure a 4.4 mm x 4.8 mm transverse spot size at the focal point of the THz optical path. The total collected energy per pulse is 0.69 mJ measured by a Joulemeter. Fitting this total energy to the spatiotemporal profile of the THz pulse yields peak e-field amplitude of 1.5 MV/cm.

TUEPPB010	Oscillator Seeding of a High Gain Harmonic Generation FEL in a Radiator-first Configuration	FEL, electron, laser, bunching	1137
	P.R. Gandhi, J.S. Wurtele UCB, Berkeley, California, USA G. Penn, M.W. Reinsch LBNL, Berkeley, California, USA
	A longitudinally coherent X-ray pulse from a high repetition rate free electron laser (FEL) is desired for a wide variety of experimental applications. However, generating such a pulse with a repetition rate greater than ~1 MHz is a significant challenge. The desired high rep rate sources, primarily high harmonic generation with intense lasers in gases or plasmas, do not exist now, and, for the multi-MHz bunch trains that superconducting accelerators can potentially produce, are likely not feasible with current technology. In this paper, we propose to place an oscillator downstream of a radiator. The oscillator generates radiation that is used as a seed for a high gain harmonic generation (HGHG) FEL which is upstream of the oscillator. For the first few pulses the oscillator builds up power and, until power is built up, the radiator has no HGHG seed. As power in the oscillator saturates, the HGHG is seeded and power is produced. The dynamics and stability of this radiator-first scheme is explored analytically and numerically. A single-pass map is derived using a semi-analytic model for FEL gain and saturation. Iteration of the map is shown to be in good agreement with simulations.

TUEPPB013	Development of an Advanced Computational Tool for Start-to-End Modeling of Next Generation Light Sources	electron, simulation, wakefield, undulator	1143
	J. Qiang, J.N. Corlett, C.E. Mitchell, C. F. Papadopoulos, G. Penn, R.D. Ryne, M. Venturini LBNL, Berkeley, California, USA
	Funding: Work supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Start-to-end simulation plays an important role in designing next generation light sources. In this paper, we present recent progress in further development and application of the parallel beam dynamics code, IMPACT, towards the fully start-to-end, multi-physics simulation of a next generation X-ray FEL light source. We will discuss numerical methods and physical models used in the simulation. We will also present some preliminary simulation results of a beam transporting through photoinjector, beam delivery system, and FEL beamlines.

TUEPPB015	Generation of Narrow-Band Coherent Tunable Terahertz Radiation using a Laser-Modulated Electron Beam	laser, electron, undulator, bunching	1146
	M.P. Dunning, C. Hast, E. Hemsing, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, Z.M. Szalata, D.R. Walz, S.P. Weathersby, D. Xiang SLAC, Menlo Park, California, USA
	Funding: Work supported by US DOE contract DE-AC02-76SF00515. The technical layout and initial results of an experiment to generate narrow-band, coherent, tunable terahertz (THz) radiation through the down-conversion of the frequency of optical lasers using a laser-modulated electron beam are described. In this experiment a 120 MeV electron beam is first energy modulated by two lasers with different wavelengths. After passing through a dispersive section, the energy modulation is converted into a density modulation at THz frequencies. This density-modulated beam will be used to generate narrow-band THz radiation using a coherent transition radiator inserted into the beam path. The central frequency of the THz radiation can be tuned by varying the wavelength of one of the two lasers or the energy chirp of the electron beam. The experiment is being performed at the NLCTA at SLAC, and will utilize the existing Echo-7 beamline, where echo-enabled harmonic generation (EEHG) was recently demonstrated.

TUPPC034	Preparation of SLS for IBS Measurements	emittance, diagnostics, optics, impedance	1233
	N. Milas, M. Böge, A. Streun PSI, Villigen, Switzerland M. Aiba, A. Lüdeke, A. Saa Hernandez Paul Scherrer Institut, Villigen, Switzerland F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland
	It is planned to use the SLS for testing damping ring issues related to linear colliders. One aspect is the study of Intra-Beam Scattering (IBS) effects, which are a limiting factor for ultra-low emittance rings. In this paper we present the setup and characterization of a new mode of operation in which the SLS runs at lower energy (1.57 GeV) with a natural emittance of 2.4 nm rad. This is much smaller than that at the nominal energy (2.41 GeV) and should make IBS effects more easily visible. In order to be able to observe IBS a careful setup is required: Optics measurement and correction as well as measurements of the bunch natural energy spread and the onset of turbulent bunch lengthening. Also, a detailed discussion on the available diagnostics and their limitations are shown and finally some preliminary results of beam emittance measurements, in all three planes, as a function of single bunch current are presented.

TUPPC074	Study of Resonance Driving Term in Electron Storage Rings	damping, resonance, storage-ring, electron	1344
	G. Liu, W. Li, L. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	The resonance driving term (RDT) is useful to analyze and optimize the nonlinear performance of the storage ring. In addition to analytical calculation of RDT, experimental measurement of RDT has been made in some proton storage rings based on turn-by-turn BPM data. For electron storage rings, the analysis is more complicated due to decoherence effects and strong radiation damping. The relation between spectral decomposition of BPM data and RDT is derived and validated using beam numerical tracking data in this paper.

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

TUPPD024	HIGH-INTENSITY LOW-ENERGY POSITRON SOURCE AT JEFFERSON LABORATORY	target, positron, simulation, solenoid	1461
	S. Golge, B. Vlahovic NCCU, Durham, USA B. Wojtsekhowski JLAB, Newport News, Virginia, USA
	We present a novel concept of a low-energy e⁺ source with projected intensity on the order of 10¹⁰ slow e+/s. The key components of this concept are a continuous wave e^- beam, a rotating positron-production target, a synchronized raster/anti-raster, a transport channel, and extraction of e⁺ into a field-free area through a magnetic plug for moderation in a cryogenic solid. Components were designed in the framework of GEANT4-based (G4beamline) Monte Carlo simulation and TOSCA magnetic field calculation codes. Experimental data to demonstrate the effectiveness of the magnetic plug is presented.

TUPPD025	REVIEWOF LOW-ENERGY POSITRON BEAM FACILITIES	positron, target, linac, neutron	1464
	S. Golge, B. Vlahovic NCCU, Durham, USA
	Positrons are produced by processes such as positive beta decay from radioactive isotopes, in nuclear reactor cores from both in-situ radioisotope radiation and pair production, and by accelerator driven beams hitting a converter target. The purpose of this paper is to review some of the prominent existing low-energy e⁺ facilities.

TUPPD055	Characterization of ps-spaced Comb Beams at SPARC	simulation, linac, bunching, laser	1527
	A. Mostacci URLS, Rome, Italy A. Bacci, A.R. Rossi Istituto Nazionale di Fisica Nucleare, Milano, Italy M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, C. Vaccarezza INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy
	SPARC in Frascati is a high brightness photo-injector used to explore advanced beam manipulation techniques. Sub-picosecond, high brightness electron bunch trains (the so called comb beam) can be generated illuminating the cathode of a RF photoinjector with a laser pulse train and via velocity bunching technique. In this paper different aspects of the physics of this advanced beam manipulation technique are discussed combining simulation and measurements. Beam dynamics numerical macroparticle simulations have been compared with the experimental results for model validation; they allow to gain insights on the beam evolution highlighting several aspects which can not be measured. In particular, we focus on the train evolution in the linac sections and in the dog-leg line up to the THz station and on the effective rms length of the single pulses within the train when it becomes shorter than the resolution.

TUPPP004	Low-alpha Operation for the SOLEIL Storage Ring	optics, injection, coupling, photon	1608
	M.-A. Tordeux, J. Barros, A. Bence, P. Brunelle, N. Hubert, M. Labat, P. Lebasque, A. Nadji, L.S. Nadolski, J.-P. Pollina SOLEIL, Gif-sur-Yvette, France C. Evain PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
	The low momentum compaction factor (alpha) operation has been recently established on the SOLEIL Storage Ring. Both time resolved X-ray and THz radiation user communities are taking benefit from a hybrid filling pattern with a 4.7 ps RMS bunch length. At a value of 1.7 10^-5 (nominal alpha /25) and a current per bunch of 65 μA, stable THz radiation is produced in the range of 8 - 20 cm^-1 (measurements and comparison with Coherent Synchrotron Radiation (CSR) modeling are reported elsewhere, ). Several low-alpha optics have been investigated and the optics presented at IPAC’11 has been selected for the operation. This paper presents the comprehensive experimental characterization of this optics. Specificities of the low-alpha operation, driven by the very demanding user experiments, are reviewed: closed orbit stability issues, extremely tight injected current step when refilling which implies a specific Linac tuning, low current diagnostics optimization, short bunch measurements, insertion devices effect on the CSR characteristics and radiation safety aspects justified by beam losses at injection. C. Evain, A. Loulergue et al., this conference. ** E. Roussel et al., this conference.

TUPPP008	Recent Results From the Short-Pulse Facility at the DELTA Storage Ring	laser, electron, undulator, synchrotron	1617
	A. Schick, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, P. Ungelenk, M. Zeinalzadeh DELTA, Dortmund, Germany
	Funding: Work supported by DFG, BMBF and by the Federal State NRW. At the 1.5 GeV synchrotron light source DELTA, operated by the TU Dortmund University, a new facility for ultrashort pulses in the VUV and THz regime is currently under commissioning. Here, the interaction of an intense, ultrashort laser pulse, co-propagating with the electrons in an optical klystron, leads to coherent synchrotron radiation at harmonics of the incident laser wavelength. The aim of the present commissioning steps is to extend the emitted wavelength down to about 50 nm, enabling femtosecond-resolved pump-probe experiments in the VUV regime. Other issues include increasing the photon flux by optimizing the laser-electron interaction and improving the stability and ease of operation of the source.

TUPPP009	Status of the PETRA III Upgrade	undulator, shielding, vacuum, site	1620
	M. Bieler, K. Balewski, W. Drube, J. Keil, A. Kling DESY, Hamburg, Germany
	Since 2010 PETRA III, a third generation light source at DESY, has been running as a user facility, with all 14 undulator beam lines operational since autumn 2011. In order to fulfill the request for more beam time after the shut down of DORIS at the end of 2012, it was decided to add two additional halls at PETRA III, each housing 5 additional beam lines. Next to these two new halls about 100 m of the accelerator will be completely remodeled to install additional undulators. The upgrade should be accomplished during a 6 month shut down in 2013. In order to minimize this down time, it was decided to keep the existing accelerator tunnel in place. This has impact both on the mechanical connection between the accelerator and the experimental floor and on the design of the optical beam lines in the tunnel. In this paper the layout of the upgraded accelerator will be shown. The design status of the major components for the upgrade will be presented.

TUPPP010	Spectral and Temporal Observations of CSR at ANKA	synchrotron, storage-ring, optics, synchrotron-radiation	1623
	V. Judin, N. Hiller, A. Hofmann, E. Huttel, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M. Schuh, M. Schwarz, N.J. Smale, M. Streichert KIT, Karlsruhe, Germany M.J. Nasse Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
	Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320. ANKA is a synchrotron light source situated at the Karlsruhe Institute of Technology. Using dedicated low-α-optics at ANKA we can reduce the bunch length and generate Coherent Synchrotron Radiation (CSR). Studies of the coherent emission in the time domain allow us to gain an insight into the longitudinal bunch dynamics. These as well as the systematic investigations of the THz spectrum range can be used for benchmarking of theoretical predictions. In this paper we report about the recent progress in CSR observation using fast THz detectors and a Martin-Puplett spectrometer at the ANKA storage ring.

TUPPP036	Large-scale Simulation of Synchrotron Radiation using a Lienard-Wiechert Approach	simulation, electron, synchrotron, synchrotron-radiation	1689
	R.D. Ryne, C.E. Mitchell, J. Qiang LBNL, Berkeley, California, USA B.E. Carlsten, N.A. Yampolsky LANL, Los Alamos, New Mexico, USA
	Funding: DOE Office of Science, Office of Basic Energy Sciences; NNSA. Synchrotron radiation is one of the most important and difficult to model phenomena affecting lepton accelerators. Large-scale parallel modeling provides a means to explore properties of synchrotron radiation that would be impossible to study through analytical methods alone. We have performed first-principles simulations of synchrotron radiation, using a Lienard-Wiechert approach, with the same number of simulation particles as would be found in bunches with charge up to 1 nC. The results shed light on the importance of shot noise effects, the amplification of coherent synchrotron radiation due to longitudinal microbunching, the interplay of electric and magnetic forces, and the limits of the widely used one-dimensional model.

TUPPP039	Vertical Dispersion Bump Design for Femto-second Slicing Beamline at the ALS	coupling, lattice, quadrupole, emittance	1698
	C. Sun, C. Steier, W. Wan LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Femto-second (fs) slicing beamline has been brought to the operation at the Advanced Light Source (ALS) since 2002. It employs the resonant interaction of an electron bunch with a fs laser beam in a wiggler to energy-modulate a short section of the bunch. The induced energy modulation is then converted to a transverse displacement using a vertical dispersion bump downstream of the wiggler. Thus, the radiation from the fs pulse can be separated from the main bunch radiation. The current dispersion bump design has proved to be an effective and reliable one. However, the ALS storage ring lattice is under an upgrade to improve its brightness. After the completion of the upgrade, a new low emittance will be implemented, and the current dispersion bump design needs to be modified to provide the adequate vertical displacement, while minimizing the vertical emittance and spurious dispersion. In this paper, we present the new design of a vertical dispersion bump using Multi-Objective Genetic Algorithm (MOGA) for the ALS upgrade lattice.

TUPPP056	Study of the Energy Chirp Effects on Seeded FEL Schemes at SDUV-FEL	FEL, electron, laser, undulator	1724
	C. Feng, D. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Seeded free-electron laser (FEL) schemes hold great promise for generation of high brilliant radiation with a narrow bandwidth. Analysis with the idealized electron beam with constant current and energy indicate that both the high-gain harmonic generation (HGHG) and the echo-enabled harmonic generation (EEHG) can produce Fourier-transform limited radiation pulses. However, residual energy variations due to nonlinearity of the accelerator or energy modulations due to microbunching instability will be unavoidable and may broaden the bandwidth of the seeded FEL. In this paper, we study the energy chirp effects on both the HGHG and EEHG schemes. Analytic and simulation calculations are presented and compared with the experimental data. Results show that the coherence properties of the EEHG FEL may not be degraded by the energy chirp when properly choosing the parameters of the dispersion sections.

TUPPP057	Design of a Wavelength Continuously Tunable Ultraviolet Coherent Light Source	FEL, laser, simulation, undulator	1727
	T. Zhang, D. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China X.M. Yang DICP, Dalian, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (Grant No. 11075199) Dalian Coherent Light Source (DCL) is a proposed FEL-based novel light source user facility, will be located in Dalian city, China. DCL will mainly servers on the field of molecular reaction dynamics, ultra-fast physical chemistry experiments, etc. Running on the High-Gain-Harmonic-Generation (HGHG) FEL mode, DCL is expected to cover the FEL wavelength from 50 nm to 150 nm, with the help of continuously tuning Optical Parametric Amplification (OPA) seed laser system, which wavelength can be varied between 240 nm and 360 nm. Numerical simulation shows that the FEL pulse energy of DCL can surpass 100 μJ, at the whole full range wavelength with the undulator tapering technology, and the photon number can be up to 10¹³ per pulse, which is sufficient for user experiments.

TUPPP059	Effects of Metal Mirrors Reflectivity and Aberrations on THz FEL Radiation Performance	FEL, cavity, undulator, electron	1729
	P. Tan, T. Yu HUST, Wuhan, People's Republic of China M. Fan, Q. Fu, D. Li, B. Qin, Y.Q. Xiong, Y.B. Yibin Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China
	The primary design study of terahertz free-electron laser (FEL) is presented in this paper. The effects of optical cavity parameter, metal mirrors reflectivity and aberrations on the THz FEL radiation performance have been explored. The reflectivity characteristics of copper, silver and gold are tested in terahertz region. The effects of metal mirrors reflectivity and aberrations on the THz FEL radiation performance are studied by numerical simulation.

TUPPP076	Soft Orbit Bumps for Duke Storage Ring VUV FEL Operation	FEL, wiggler, electron, dipole	1774
	S.F. Mikhailov, J.Y. Li, V. Popov, P.W. Wallace, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	Funding: This work is supported in part by the US DoE grant # DE-FG02-97ER41033. The Duke FEL and High Intensity Gamma-ray Source (HIGS) facility is operated with an electron beam from 0.24 to 1.2 GeV and a photon beam from 190 to 1060 nm. The current range of the gamma-beam energy is from 1 MeV to about 100 MeV, with the maximum total gamma-flux of more then 10¹⁰ gammas per second around 10 MeV. Production of the high intensity, high energy gamma-beams of 60-100 MeV using UV-VUV mirrors of 240 - 190 nm requires and high energy, high current electron beams of 0.9-1.05 GeV. The radiation damage problem becomes more severe for VUV FEL operation below 190 nm. The radiation from the End-of-Arc (EOA) bending magnets, instead of the radiation from FEL wigglers, is the dominant cause of a rapid degradation of the downstream FEL mirror. In this work, we propose a number of measures to significantly reduce the radiation from these dipole magnets as well as other potential sources of synchrotron radiation toward the FEL mirror. In particular, we describe the development of an orbit bump using designated "soft" orbit correctors. The magnetic field of these correctors is limited to produce a radiation with a critical wavelength close or below the FEL wavelength.

TUPPP082	Optimization of a Terawatt Free Electron Laser	undulator, FEL, electron, focusing	1780
	J. Wu, X. Huang, Y. Jiao, A.U. Mandlekar, T.O. Raubenheimer, S. Spampinati, G. Yu SLAC, Menlo Park, California, USA P. Chu FRIB, East Lansing, Michigan, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515. There is great interest in generating a terawatt (TW) hard X-ray free electron laser (FEL) that will enable coherent diffraction imaging of complex molecules like proteins and probe fundamental high-field physics. A feasibility study of producing such pulses was carried out em- ploying a configuration beginning with an SASE amplifier, followed by a "self-seeding" crystal monochromator, and finishing with a long tapered undulator. The undulator tapering profile, the phase advance in the undulator break sections, the quadrupole focusing strength, etc. are parameters to be optimized. A genetic algorithm (GA) is adopted for this multi-dimensional optimization. Concrete examples are given for LCLS/LCLS-II systems.

TUPPP083	Multi-Dimensional Optimization of a Tapered Free Electron Laser	undulator, FEL, electron, focusing	1783
	Y. Jiao, J. Wu SLAC, Menlo Park, California, USA Q. Qin IHEP, Beijing, People's Republic of China
	Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. In this paper, we report a multi-dimensional optimizer to maximize the radiation power in a tapered FEL by searching for an optimal taper profile as well as a reasonable variation in electron beam radius. Applications of the proposed multi-dimensional optimization to the terawatt-level, tapered FELs with LCLS-like electron beam parameters are presented, and the proposed optimization scheme is compared with the GINGER’s self-design taper algorithm. At the end, the dependence of the available maximum radiation power on various parameters of the initial electron beam, the initial radiation field and the undulator system is summarized.

TUPPP084	Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius	electron, undulator, FEL, simulation	1786
	Y. Jiao, J. Wu SLAC, Menlo Park, California, USA Q. Qin IHEP, Beijing, People's Republic of China
	Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. An in-depth understanding of the tapering-related physics is required to explore the full potential of a tapered FEL, not only by tapering the undulator parameters in longitudinal dimension, but also optimizing the transverse effects. Based on the modified 1D FEL model and time-steady numerical simulations, we study the contribution of the variation in electron beam radius and the related transverse effects. Taking a terawatt-level, 120-m tapered FEL as example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.

TUPPP090	Studies of Controlled Laser-induced Microbunching Instability at Source Development Laboratory	laser, electron, linac, space-charge	1798
	S. Seletskiy, B. Podobedov, Y. Shen, X. Yang BNL, Upton, Long Island, New York, USA
	We present the studies of controlled microbunching intentionally induced on the beam by the photocathode laser with modulated longitudinal profile. Varying the depth and frequency of longitudinal modulation of the laser pulse allowed us to observe the development of microbunching instability at BNL Source Development Laboratory (SDL) in the controlled environment. That allowed us to benchmark the model of the microbunching gain for the first time. In addition to that, we demonstrated for the first time a constructive work of a so-called longitudinal space charge amplifier, which in case under consideration can be utilized for enhancement of linac-based sources of THz radiation.

TUPPR004	ILC Conventional Facility in Asian Sites	site, linac, HLRF, cryogenics	1816
	A. Enomoto, M. Miyahara KEK, Ibaraki, Japan
	The international linear collider (ILC) is on a stage of preparing technical design report (TDR). Through value engineering to reduce civil construction costs, the tunnel configuration was changed from double- tunnel scheme to single. The double-tunnel schme accomodates superconducting accelerator modules and their power supplies indipendently. This is a very natural scheme for setting an accelerator and its power supply nearby and for preventing radiation damage of the power supply. However, the single-tunnel scheme was proposed to reduce cost, and to avoid such radiation problem three kinds of high-level (HLRF) RF systems are proposed. We report the comparison of ILC main linac costs and construction schedules between eight cases for combinations of diferent tunnel excavation methods and HLRF systems; then, we report the potential facility design for the Asian sites.

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

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

TUPPR023	Final-Focus Optics for the LHeC Electron Beam Line	synchrotron, quadrupole, synchrotron-radiation, electron	1861
	J.L. Abelleira EPFL, Lausanne, Switzerland J.L. Abelleira, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland H. Garcia UPC, Barcelona, Spain
	Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579. One of the options considered for the ECFA-CERN-NuPECC design study for a Large Hadron electron Collider (LHeC)* based on the LHC is adding a recirculating energy-recovery linac tangential to the LHC. First designs of the electron Final Focus System have shown the need to correct the chromatic aberrations. Two designs using different approaches for the chromaticity correction are compared, namely, the local chromaticity correction** and the traditional approach using dedicated sections. LHeC Study Group, “A Large Hadron Electron Collider at CERN,” LHeC-Note 2011-001 (2011). *J. Abelleria et al., "Design Status of LHeC Linac‐Ring Interaction Region," IPAC2011, p. 2796 (2011).

TUPPR045	Multi-cell VEP Results: High Voltage, High Q, and Localized Temperature Analysis	cavity, SRF, controls, monitoring	1918
	F. Furuta, B. Elmore Cornell University, Ithaca, New York, USA A.C. Crawford Fermilab, Batavia, USA G.M. Ge, G.H. Hoffstaetter, M. Liepe CLASSE, Ithaca, New York, USA
	We are developing Vertical Electro Polishing (VEP) system for niobium superconducting RF cavity at Cornell University. VEP has been successfully applied on different cell shapes (TESLA and Re-entrant), and single and multi-cell cavities. VEP achieved high gradient of 39MV/m with TESLA shape single cell and of 36MV/m with TESLA shape 9-cell, respectively. Preliminary results of R&D on VEPed cavities show removal dependence on cavity performance. Temperature oscillation asymmetry was also found during the VEP process. We will report these recent results and further R&D plan of Cornell VEP.

TUPPR053	Conceptual Design of the Linac4 Main Dump	linac, simulation, proton, booster	1939
	I.V. Leitao, C. Maglioni, A. Sarrió Martínez CERN, Geneva, Switzerland
	Linac4 is the new CERN linear accelerator intended to replace the aging Linac2 as the injector to the Proton Synchrotron Booster (PSB) for increasing the luminosity of the Large Hadrons Collider (LHC). By delivering a 160MeV H⁻ beam, Linac4 will provide the necessary conditions to double the brightness and intensity of the beam extracted from the PSB. This paper describes the conceptual design of the Linac4 Main Dump, where two different concepts relying respectively on water and air cooling were compared and evaluated. Based on the application of analytical models for the energy deposited by the beam, heat conduction and cooling concepts, a parametric study was performed. This approach allowed the identification of the “optimal” configuration for these two conceptual geometries and their relative comparison. Besides giving the theoretical guidelines for the design of the new dump, this work also contributes to the development of analytical tools to allow a better understanding of the influence of the several design parameters in this type of low-energy beam intercepting devices.

TUPPR054	Internal H⁰/H⁻ Dump for the Proton Synchrotron Booster Injection at CERN	vacuum, booster, linac, injection	1942
	M. Delonca, C. Maglioni, A.A. Patapenka, A. Sarrió Martínez CERN, Geneva, Switzerland
	In the frame of the LHC Injectors Upgrade Project at CERN (LIU), the new 160MeV H⁻ Linac4 will inject into the four existing PS Booster rings after the conversion of H⁻ into H⁺ in a stripping foil. Given a limited stripping efficiency and possible foil failures, a certain percentage of the beam is foreseen to remain partially (H⁰) or completely (H⁻) unstripped. An internal dump installed into the chicane magnet to stop these unstripped beams is therefore required. This paper presents the conceptual design of the internal dump, reviewing loading assumptions, design constraints, limitations and integration studies. Power evacuation through the thermal contact between the core and the external active cooling is addressed and, finally, results from the numerical thermo-mechanical analyses are reported.

TUPPR067	Electromagnetic Field of Charged Particle Bunch Moving in Wire Metamaterial	electromagnetic-fields	1975
	V.V. Vorobev, A.V. Tyukhtin Saint-Petersburg State University, Saint-Petersburg, Russia
	Funding: Saint Petersburg State University We consider the field of bunch flying through a "wire metamaterial". Analytical and computational investigations are carried out. In the case of motion perpendicularly to the wires it is shown that the radiation concentrates in a small vicinity of the determined lines behind the bunch and the Pointing vector is directed along the wires. This phenomenon can be useful for charged bunch examination. Some calculations show that the measurements of electrical field intensity and energy flow density allow determining the length of the bunch and its velocity. The case of bunch moving along the wires is also examined. It is shown that the radiation can be generated only for the wires possessing non-conducting coating. The radiation is directed at a sharp angle to the wires.

WEXB01	Recent Advances and New Techniques in Visualization of Ultra-short Relativistic Electron Bunches	electron, laser, FEL, RF-structure	2091
	D. Xiang SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. DOE under Contract No. DE-AC02-76SF00515. This talk will address advances in the measurement of ultra-short relativistic bunches at femtosecond frontier in high-energy x-ray free-electron lasers (FELs). In general, this presentation will discuss several recently proposed novel techniques (i.e. mapping z exactly to delta * and x , optical oscilloscope , etc.) that are capable of breaking the femtosecond time barrier in measurements of ultrashort bunches. In particular, this presentation will report on the all-optical, time-resolved method to probe beam longitudinal phase space with femtosecond time scale and 10^-5 energy scale resolution *. The simultaneous measurement of temporal profile and beam slice energy spread after the FEL interaction is also shown to reveal the time-dependent x-ray radiation profile **. Z. Huang et al., PRSTAB 13, 092801. D. Xiang, Y. Ding, PRSTAB 13, 094001. * G. Andonian et al., PRSTAB 14, 072802. ** D. Xiang et al., PRSTAB 14, 112801. *** Y. Ding et al., FEL11.
	Slides WEXB01 [6.873 MB]

WEXB02	Diagnostics for High Power Targets and Dumps	target, diagnostics, proton, vacuum	2096
	E. Gschwendtner CERN, Geneva, Switzerland
	High power targets and dumps are generally used for neutrino, antiproton, neutron and secondary beam production, or in waste management using intense beams. In order to guarantee an optimized and safe use of these targets and dumps, reliable instrumentation is needed; the diagnostics in high power beams around targets and dumps is reviewed. The suite of beam diagnostic devices used in such extreme environments is discussed, including their role in commissioning and operation. The handling and maintenance of the instrumentation components in high radiation areas will be addressed.
	Slides WEXB02 [13.010 MB]

WEOAA02	Inorganic Scintillators for Particle Beam Profile Diagnostics of Highly Brilliant and Highly Energetic Electron Beams	electron, diagnostics, simulation, monitoring	2119
	G. Kube, C. Behrens, C. Gerth, B. Schmidt DESY, Hamburg, Germany W. Lauth IKP, Mainz, Germany M. Yan Uni HH, Hamburg, Germany
	Transverse beam profile diagnostics in electron linacs are widely based on optical transition radiation (OTR) as standard technique. The experience from modern linac based light sources shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. As consequence, for the new 4th generation light sources as the European X-FEL, new reliable tools for transverse beam profile measurements are required. Scintillating screens are widely used for particle beam diagnostics, especially in transverse profile measurements at hadron machines and low energy electron machines where the intensity of OTR is rather low. Their usage may serve as an alternative way to overcome limitations in OTR based beam diagnostics imposed by the influence of coherent emission. However, there is only little information about scintillator properties for applications with high energetic electrons. Therefore, test experiments have been performed at the Mainz Microtron (MAMI) in order to study the screen applicability. The status of these experiments will be presented and the results will be discussed in view of scintillator material properties and observation geometry.
	Slides WEOAA02 [1.648 MB]

WEOBB01	Measurement of the Local Energy Spread of Electron Beam at SDUV-FEL	laser, electron, FEL, bunching	2143
	C. Feng, J.H. Chen, H.X. Deng, T. Lan, B. Liu, D. Wang, X. Wang, M. Zhang, T. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	The slice energy spread of electron beam is a very important parameter for high gain free electron lasers (FELs) especially the seeded FELs. Because of its extremely small value, highly accurate measurement of the slice energy spread is rather challenging. In this paper, we propose a novel method to accurately measure the slice energy spread based on the coherent harmonic generation (CHG) scheme. This method has been demonstrated on the Shanghai deep ultraviolent FEL (SDUV-FEL), and the results show that the slice energy spread is about only 1.2keV at the exit of the 136MeV linac when the bunch compressor is off, and this value change to about 2.6keV when the bunch compressor is on. * Chao Feng, et al, Phys. Rev. ST Accel. Beams 14, 090701 (2011)
	Slides WEOBB01 [3.309 MB]

WEOBB03	Computation of the Wigner Distribution for Undulator Radiation	undulator, electron, synchrotron, brightness	2149
	I.V. Bazarov, A.D. Gasbarro CLASSE, Ithaca, New York, USA
	In the effort to optimize brightness in synchrotron radiation sources, questions arise as to the most desirable electron beam parameters given a particular insertion device. With a detailed understanding of the distribution of emitted photons, the electron beam profile can be effectively matched. We have developed tools which, by way of the Wigner distribution, compute the phase space of photons radiated by an electron bunch. An explanation is provided of the workings of the code itself with mention of important algorithms that have been implemented. We demonstrate via numerical examples the Wigner distributions of the undulator radiation. In particular, it is shown that the phase space of light differs appreciably from the Gaussian distribution assumed in many analytical expressions and, therefore, the more thorough approaches should be used for computation of related quantities.
	Slides WEOBB03 [2.555 MB]

WEIC02	Future Medical Accelerator	neutron, proton, target, controls	2152
	K. Yasuoka Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
	In the future radiation/particle therapy, the 3D-methods would be expanded into 4D- and 5D-methods to achieve precise biological dose focused on tumor cells and to spare normal cells as much as possible. No further technologies would be required to develop the next accelerator for radiation/particle therapy except for accelerator- and hospital- based BNCT. The BNCT needs a “medical neutron accelerator” to produce high intensity epithermal neutrons.
	Slides WEIC02 [3.054 MB]

WEIC04	Functional Materials Development using Accelerator-based Light Sources: Current Capabilities and Future Prospects	FEL, controls, synchrotron, electron	2156
	W.R. Flavell UMAN, Manchester, United Kingdom
	Funding: UK Engineering and Physical Sciences Research Council (EPSRC), UK Science and Technology Facilities Council (STFC) The development of accelerator-based light sources has allowed access to photons of very high brightness and wide tunability. These properties of synchrotron radiation (SR) mean that it can be used to resolve questions that can be answered in no other way, enabling unique contributions to the development of functional materials. Increasingly, these benefits have become essential to material evaluation in manufacturing – ranging from intelligent catalysts for automotive emissions control* to next generation photovoltaics. Bright, tunable X-rays have been a boon to nanotechnology* in particular, with its requirement for atom-by-atom understanding – and this benefit is enhanced by the microfabrication capabilities of X-ray lithography in LIGA-based techniques. The result is unique potential for nanoscale device manufacture. The application of bright tunable X-rays to the development of nanostructures for a range of industrial applications is illustrated, and the prospects for exploitation of the ultra-high brightness and femtosecond time structure of FEL radiation are discussed. * H Tanaka et al., Ang. Chemie Int. Ed. 45, 5998 (2006) S J O Hardman et al., Phys Chem Chem Phys 13, 20275 (2011) * S Biswas et al., Small (2012) DOI: 10.10⁰²/smll201102100
	Slides WEIC04 [11.723 MB]

WEEPPB007	Initial Testing of the Mark-0 X-band RF Gun at SLAC	gun, solenoid, vacuum, cathode	2179
	A.E. Vlieks, C. Adolphsen, V.A. Dolgashev, J.R. Lewandowski, C. Limborg-Deprey, S.P. Weathersby SLAC, Menlo Park, California, USA
	A new X band RF Gun (Mark-0) has been assembled, tuned and is being tested in the ASTA facility at SLAC. This gun has been improved from an earlier gun used in Compton-scattering experiments at SLAC by the introduction of a racetrack dual-input coupler to reduce quadrupole fields. Waveguide-to-coupler irises were also redesigned to reduce surface magnetic fields and therefore peak pulse surface heating. Tests of this photocathode gun will allow us to gain early operational experience for beam tests of a new gun with further improvements (Mark-1) being prepared for SLAC’s X-Band Test Accelerator (XTA) program and the LLNL MegaRay program. Results of current testing up to ≈ 200 MV/m peak surface Electric fields will be presented.

WEPPC011	Vertical Test Results for ERL 9-cell Cavities for Compact ERL Project	cavity, linac, cryomodule, HOM	2227
	K. Umemori, T. Furuya, H. Sakai, M. Satoh, K. Shinoe KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan M. Sawamura JAEA, Ibaraki-ken, Japan
	The Compact ERL project, which is a test facility of ERL, is ongoing in Japan. At the first step of this project, main linac cavities accelerate electron beams by 30 MV. Two 9-cell cavities were fabricated for main linac cryomodule, under High Pressure Gas Safety Code in Japan. A series of surface treatments, such as annealing, pre-tuning, electro-polishing (EP), degreasing, high pressure rinsing by ultra-pure water, cavity assembly and baking, were applied for the cavities. For the final EP, current density was selected to be relatively low. Vertical tests were performed for both cavities. Their field successfully reached to 25 MV/m, without any field limitation. The Q-values were more than 1x10¹⁰, even at 20 MV/m. Field emission on-sets were to be 14 and 22 MV/m, for each cavities. Both cavities satisfied requirements for ERL main linac cavity. Details of vertical tests, with X-ray and temperature mapping data, are shown, in this paper. These cavities will be mounted with titanium He jackets, assembled and installed into a cryomodule.

WEPPC014	Construction and Beam Operation of Capture Cryomodule for Quantum Beam Experiments at KEK-STF	cryomodule, cavity, controls, status	2236
	Y. Yamamoto KEK, Ibaraki, Japan
	Construction of capture cryomodule for Quantum Beam Project has started since September, and will be finished by the end of December in 2011 at KEK-STF. Two MHI cavities (MHI-12, -13), which reached ILC specification (0.8x10¹⁰ at 35MV/m) at the vertical test, were installed into a short cryomodule with improved input couplers. Slide-Jack tuner was attached at different position (center or end of helium jacket) for each cavity same as S1-Global. From January 2012, this cryomodule will be cooled down to 2K, and the high power test will be started including check of the cavity/coupler/tuner performance, LFD measurement, LFD compensation by Piezo, dynamic loss measurement and so on. From March, the beam operation with the beam current of 10mA and the maximum beam energy of 40MeV, will be started to generate x-rays by collision between electron beam and laser. At this stage, two cavities will be operated at the lower gradient of 15-20MV/m, and the stable operation is crucial. In this report, the test results of various performances at the Quantum Beam Project will be presented in detail.

WEPPC050	Main Couplers for Project X	vacuum, cavity, linac, cryomodule	2324
	S. Kazakov, M.S. Champion, S. Cheban, T.N. Khabiboulline, M. Kramp, Y. Orlov, V. Poloubotko, O. Pronitchev, V.P. Yakovlev Fermilab, Batavia, USA
	Design of 325MHz and 650MHz multi-kilowatt CW main couplers for superconducting linac of Project X is described. Results of electrodynamics, thermal and mechanical simulations is presented.

WEPPC070	Automated Cavity Test Suite for Cornell's ERL Program	cavity, controls, EPICS, linac	2372
	D. Gonnella, M. Liepe, N.R.A. Valles CLASSE, Ithaca, New York, USA
	As of 2011, fabrication and testing of main linac 7-cell cavities has begun for Cornell's Energy Recovery Linac prototype project. To standardize the testing process, minimize errors and allow for quick and precise measurements of these cavities, a suite of MatLab programs has been written to automate cavity tests. The programs allow measuring the quality factor versus temperature, and quality factor vs. accelerating gradient, and allow extracting material properties such as RRR and residual resistance. They are compatible with EPICS input/output controllers or standalone computers. Finally, the program can measure continuous Q vs E curves from a single high field decay curve, and can perform temperature mapping and quench localization from oscillating superleak transducer data.

WEPPC088	Standardization of CEBAF 12 GeV Upgrade Cavity Testing	cavity, HOM, survey, LabView	2420
	T. Bass, G.K. Davis, C. Grenoble, M. Stirbet JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. CEBAF 12GeV upgrade project includes 80 new 7-cell cavities to form 10 cryomodules. Each cavity underwent RF qualification at 2 Kelvin using a high power accelerating gradient test and an HOM survey in JLab’s Vertical Testing Area (VTA) before cavity string assembly. In order to ensure consistently high quality data, updated cavity testing procedures and analysis were implemented and used by a group of 10 VTA operators. For high power tests, a cavity testing procedure was developed and used in conjunction with a LabVIEW program to collect the test data. Additionally while the cavity was at 2K, an HOM survey was performed using a network analyzer and a combination of Excel and Mathematica programs. Data analysis was standardized and an online logbook, Pansophy, was used for data storage and mining. The Pansophy system allowed test results to be easily summarized and searchable across all cavity tests. In this presentation, the CEBAF 12GeV upgrade cavity testing procedure, method for data analysis, and results reporting results will be discussed.

WEPPC089	SRF Cavity Performance Overview for the 12 GeV Upgrade	cavity, cryomodule, SRF, HOM	2423
	A. Burrill, G.K. Davis, C.E. Reece, A.V. Reilly, M. Stirbet JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The CEBAF accelerator, a recirculating CW electron accelerator that is currently operating at Jefferson Laboratory, is in the process of having 10 new cryomodules installed to allow for the maximum beam energy to be increased from 6 GeV to 12 GeV. This upgrade required the fabrication, processing and RF qualification of 80, seven cell elliptical SRF cavities, a process that was completed in February 2012. The RF performance achieve in the vertical testing dewars has exceeded the design specification by ~25% and is a testament to the cavity design and processing cycle that has been implemented. This paper will provide a summary of the cavity RF performance in the vertical tests, as well as review the overall cavity processing cycle and duration for the project.

WEPPC095	Evaluation of Silicon Diodes as In-situ Cryogenic Field Emission Detectors for SRF Cavity Development	cavity, ion, SRF, cryogenics	2438
	A.D. Palczewski, R.L. Geng JLAB, Newport News, Virginia, USA
	Funding: This work is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. We performed in-situ cryogenic testing of five silicon diodes as possible candidates for field emission monitor of SRF cavities in vertical testing dewars and in cryo-modules. We evaluated diodes from 2 companies - from Hamamatsu corporation model S5821-02 (used at KEK)* and S1223-02; and from OSI Optoelectronics models OSD35-LR-A, XUV-50C, and FIL-UV20. The measurements were done by placing the diodes in superfluid liquid helium near a field emitting 9-cell cavity during its vertical test. For each diode, we will discuss their viability as a 2K cryogenic detector for FE mapping of SRF cavities and their directionality in such environments. We will also present calibration curves between the diodes and JLab’s standard radiation detector placed above the dewar top plate and within radiation shielding. * H. Sakai et al., Proc of IPAC10, WEPEC028 p. 2950 (2010).

WEPPD007	Integrated Thermal Analysis of the FRIB Cryomodule Design	cryomodule, cryogenics, vacuum, simulation	2510
	Y. Xu, M. Barrios, F. Casagrande, M.J. Johnson, M. Leitner FRIB, East Lansing, Michigan, USA D. Arenius, V. Ganni, W.J. Schneider, M. Wiseman JLAB, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 Thermal analysis of the FRIB cryomodule design is performed to determine the heat load to the cryogenic plant, to minimize the cryogenic plant load, to simulate thermal shield cool down as well as to determine the pressure relief sizes for failure conditions. Static and dynamic heat loads of the cryomodules are calculated and the optimal shield temperature is determined to minimize the cryogenic plant load. Integrated structural and thermal simulations of the 1100-O aluminium thermal shield are performed to determine the desired cool down rate to control the temperature profile on the thermal shield and to minimize thermal expansion displacements during the cool down. Pressure relief sizing calculations for the SRF helium containers, solenoids, helium distribution piping, and vacuum vessels are also described. Michigan State University designs and establishes FRIB as a DOE Office of Science National User Facility in support of the mission of the Office of Nuclear Physics.

WEPPD019	Manufacturing and Welding Process of Straight Section of Aluminum Alloy UHV Chambers for Taiwan Photon Source	vacuum, photon, synchrotron, synchrotron-radiation	2537
	C.-C. Chang, C.K. Chan, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu NSRRC, Hsinchu, Taiwan
	This paper describes the manufacturing process and welding sequence for the aluminum extrusion vacuum chamber for the straight sections in Taiwan Photon Source. The straight section composes of aluminum extrusion chamber of A6063 and BPM chamber of A6061 aluminum alloys. The straightness and flatness of these extrusion chambers are controlled under 0.1mm/m and 0.2mm/m, respectively. The BPM chambers are manufactured precisely in oil-free environment, which provide clean surface and a precise sealing surface after machining. All the components are assembled in pre-aligned support system through the welding process. The aluminum chamber for 24 straight sections has been welded. The results show the straightness of < 0.15mm/m, flatness of < 0.3mm/m, and leakage rates of < 2 × 10^-10 mbarl/sec. were achieved.

WEPPD025	LHC Detector Vacuum System Consolidation for Long Shutdown 1 (LS1) in 2013-2014	vacuum, ion, background, electron	2555
	M.A. Gallilee, J. Chaure, P. Cruikshank, J.E. Gallagher, C. Garion, J.M. Jimenez, R. Kersevan, H. Kos, L. Leduc, P. Lepeule, N. Provot, H. Rambeau, R. Veness CERN, Geneva, Switzerland
	The LHC has ventured into unchartered territory for Particle Physics accelerators. A dedicated consolidation program is required between 2013 and 2014 to ensure optimal physics performance. The experiments, ALICE, ATLAS, CMS, and LHCb, will utilise this shutdown, along with the gained experience of three years of physics running, to make optimisations to the detectors. New vacuum technologies have been developed for the experimental areas, to be integrated during this first phase shutdown. These technologies include bellows, vacuum chambers and ion pumps in aluminium, new beryllium vacuum chambers, and composite mechanical supports. An overview of this first phase consolidation program for the LHC experiments is presented.

WEPPD030	Concept for the Antiproton Production Target at FAIR	target, antiproton, proton, synchrotron	2570
	K. Knie, B. Franzke, V. Gostishchev, M. Steck GSI, Darmstadt, Germany P. Sievers CERN, Geneva, Switzerland
	We will report on the status of the antiproton production target for the FAIR facility. A Ni target will be bombarded by a pulsed beam of 29 GeV protons with an intensity of 2.5·10¹³ ppp and a repetition rate of 0.2 Hz. Directly after the target the antiprotons will be focussed by a magnetic horn. In the proceeding magnetic separator antiprotons with an energy of 3 GeV (± 3%) will be selected and transported to the antiproton collector ring. The planned setup of the target area, including radiation protection issues, will be presented,

WEPPD033	Design of 100 MeV Proton Beam Irradiation Facility for the PEFP 100 MeV Linac	proton, target, linac, octupole	2579
	S.P. Yun, Y.-S. Cho, J.-H. Jang, H.S. Kim, H.-J. Kwon, B.-S. Park, K.T. Seol, Y.-G. Song KAERI, Daejon, Republic of Korea
	Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government. The Proton Engineering Frontier Project (PEFP) will install a 100-MeV proton linear accelerator at Gyeong-ju site. Two target rooms ( TR 103, TR 23) will be prepared in the beam commissioning stage for 20-MeV and 100-MeV proton beams, respectively. To design the irradiation equipment in TR 103, we have investigated general propagation shape and spatial distribution of proton beam by using Monte carlo method, when 100 MeV proton beam extracted from vacuum in the beam lines through beam window. On the basis of this result, we have designed beam irradiation components and their configuration. The beam irradiation facility consists of beam dump, support frame, sample support and beam current monitor. To minimize residual radioactivity induced by incident proton beam, the graphite was selected as the material of beam dump and the aluminum alloy was selected as material of other irradiation equipment. These residual radioactivity of equipment were estimated by Monte carlo method. In this paper, the details of this irradiation equipment design are presented.

WEPPD034	Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab	cryomodule, electron, neutron, status	2582
	C.M. Baffes, M.D. Church, J.R. Leibfritz, S.A. Oplt, I.L. Rakhno Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility’s initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type RF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a Helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. In addition, the potential for radiation-induced degradation of the graphite is discussed.

WEPPD035	Design Considerations for an MEBT Chopper Absorber of 2.1MeV H⁻ at the Project X Injector Experiment at Fermilab	vacuum, ion, cryomodule, neutron	2585
	C.M. Baffes, M.H. Awida, A.Z. Chen, Y.I. Eidelman, V.A. Lebedev, L.R. Prost, A.V. Shemyakin, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy The Project X Injector Experiment (PXIE) will be a prototype of the Project X front end that will be used to validate the design concept and decrease technical risks. One of the most challenging components of PXIE is the wide-band chopping system of the Medium Energy Beam Transport (MEBT) section, which will form an arbitrary bunch pattern from the initially CW 162.5 MHz 5mA beam. The present scenario assumes diverting 80% of the beam to an absorber to provide a beam with the average current of 1mA to SRF linac. This absorber must withstand a high level of energy deposition and high ion fluence, while being positioned in proximity of the superconductive cavities. This paper discusses design considerations for the absorber, including specific challenges as spreading of energy deposition, management of temperatures and temperature-induced mechanical stresses, radiation effects, surface effects (sputtering and blistering), and maintaining vacuum quality. Thermal and mechanical analyses of a conceptual design are presented, and future plans for the fabrication and testing of a prototype are described.

WEPPD036	Energy Flow and Deposition in a 4-MW Muon Collider Target System	target, shielding, collider, factory	2588
	N. Souchlas, R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA X.P. Ding UCLA, Los Angeles, California, USA V.B. Graves ORNL, Oak Ridge, Tennessee, USA H.G. Kirk, H. K. Sayed BNL, Upton, Long Island, New York, USA K.T. McDonald PU, Princeton, New Jersey, USA
	Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886 The design of the target station for a 4-MW Muon Collider or a Neutrino Factory is evolving to include more space for services to the magnets and internal tungsten shielding, as well as consideration of removing the 5-T resistive copper coils, thereby reducing the peak field from 20 to 15 T. Simulations with MARS15 have been performed to verify that these revisions preserve sufficient shielding that the peak power deposition everywhere in the superconducting magnets will be less than 0.1 mW/g, permitting at least a 10-year operational lifetime against radiation damage to the organic insulators.

WEPPD040	Power Saving Schemes in the NSRRC	controls, synchrotron, synchrotron-radiation, status	2600
	J.-C. Chang, Y.F. Chiu, Y.-C. Chung, Y.-C. Lin, C.Y. Liu, Z.-D. Tsai, T.-S. Ueng NSRRC, Hsinchu, Taiwan
	To cope with increasing power consumption and huge power bill of the Taiwan Photon Source (TPS) in the near future, we have been conducting several power saving schemes in the National Synchrotron Radiation Research Center (NSRRC) for years. This paper illustrates the power saving results and future schemes. The power saving schemes include optimization of chillers operation, power requirement control, air conditioning system improvement, application of heat pump, and the lighting system improvement.

WEPPD061	Quality Control of Modern Linear Accelerator: Dose Stability Long and Short-term	controls, factory, photon, monitoring	2660
	T.U. Uddin NICRH, Dhaka, Bangladesh
	Quality Control (QC) data of modern linear accelerators, collected by National Institute of Cancer Research and Hospital, Dhaka, Bangladesh between the years 2006 and 2010, were analyzed. The goal was to provide information for the evaluation and elaboration of QC of accelerator outputs and to propose a method for QC data analysis. Short- and long-term drifts in outputs were quantified by fitting empirical mathematical models to the QA measurements. Normally, long-term drifts were well (≤1.5%) modeled by either a straight line or a single-exponential function. A drift of 2% occurred in 18 ± 12 months. The shortest drift times of only 2–3 months were observed for some new accelerators just after the commissioning but they stabilized during the first 2–3 years. The short-term reproducibility and the long-term stability of local constancy checks, carried out with a sealed plane parallel ion chamber, were also estimated by fitting empirical models to the QC measurements. The reproducibility was 0.3–0.6% depending on the positioning practice of a device. Long-term instabilities of about 0.3%/month were observed for some checking devices.

WEPPP012	High-Gradient THz-Scale Two-Channel Coaxial Dielectric-Lined Wakefield Accelerator	wakefield, acceleration, vacuum, focusing	2747
	S.V. Shchelkunov, M.A. LaPointe Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA J.L. Hirshfield, T.C. Marshall Omega-P, Inc., New Haven, USA G.V. Sotnikov NSC/KIPT, Kharkov, Ukraine
	Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics. A mm-scale THz Coaxial Dielectric Wakefield Accelerator structure is currently under study by Yale University Beam Physics Lab and collaborators for its performance with annular drive bunches. With our recent successful experiments with the cm-scale GHz rectangular module at AWA/Argonne (USA) and planned activity there with yet another cm-scale GHz coaxial structure, the program of new research has two objectives. The first is to design a structure to produce acceleration gradients approaching 0.35 GeV/m per each nC of drive charge when excited by an annular-like bunch; has an attractive feature that the drive and accelerated bunches both have good focusing and stability properties; and also exhibits a large transformer ratio. The second goal is to build and test the structure at FACET/SLAC (USA). At FACET the structure can be excited only with the available pencil-like drive bunch, but the reciprocity principle allows one to observe some of the properties that would be seen if the excitation were to be by an annular drive bunch. This presentation shows our latest findings, discusses related issues, and discusses our plans for experiments.

WEPPP022	Analysis of a Rectangular Dielectric-lined Accelerating Structure with an Anisotropic Loading	wakefield, electron, acceleration, impedance	2769
	I.L. Sheynman, S. Baturin LETI, Saint-Petersburg, Russia A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA
	Funding: Russian Fund of Basic Research Federal target program "Scientific and scientific and pedagogical personnel of innovative Russia" of the Ministry of Education and Science of Russia. Analysis of Cherenkov radiation generated by high current relativistic electron bunch passing through a rectangular waveguide with anisotropic dielectric loading has been carried out. Some of the materials used for the waveguide loading of accelerating structures (sapphire) possess significant anisotropic properties. In turn, it can influence excitation parameters of the wakefields generated by an electron beam. Using orthogonal eigenmodes decomposition for the rectangular dielectric waveguide, the analytical expressions for the wakefields have been obtained. Numerical modeling of the longitudinal and transverse (deflecting) wakefields has been carried out as well. It is shown that the dielectric anisotropy causes frequency shift in comparison to the dielectric-lined waveguide with the isotropic dielectric loading.

WEPPP023	Radiation of a Bunch Intersecting a Boundary between Vacuum and Dielectric in a Circular Waveguide	vacuum, wakefield, acceleration, plasma	2772
	T.Yu. Alekhina, A.V. Tyukhtin Saint-Petersburg State University, Saint-Petersburg, Russia
	Funding: Saint Petersburg State University Analysis of a field of a particle bunch in a waveguide loaded with a dielectric is important for the wakefield acceleration technique and for other problems in accelerator physics. We investigate the field of the bunch crossing a boundary between two dielectrics in a circular waveguide. We take into account the finite length of the bunch and analyze both the field structure and the energy loss. Special attention is paid to two cases: the bunch flies from vacuum into dielectric and from dielectric into vacuum. In the first case, investigation of formation of stationary wakefield is of interest (this is important for the wakefield acceleration technique). In the second case, quasi monochromatic wave is generated in the vacuum region. This effect can be used for elaboration of a quasi-monochromatic radiation generator of new type. In both cases we also study dynamics of the energy loss of the bunch. * T.Yu. Alekhina, A.V. Tyukhtin. Proc. of IPAC2011, San Sebastian, Spain, WEPZ012, p. 2793 (2011).

WEPPP024	Cherenkov Radiation from a Small Bunch Moving in a Cold Magnetized Plasma	plasma, wakefield, acceleration, electromagnetic-fields	2775
	S.N. Galyamin, D.Y. Kapshtan, A.V. Tyukhtin Saint-Petersburg State University, Saint-Petersburg, Russia
	Funding: Saint Petersburg State University. Investigation of the bunch radiation in plasma is important for the plasma wakefield acceleration (PWFA) technique and other applications in accelerator physics. We study the electromagnetic field of small relativistic bunch moving in a magnetized cold plasma along the magnetic field. The energy loss of the bunch was investigated earlier, however the structure of electromagnetic field was not analyzed. We perform analytical and numerical investigation of total field. Different equivalent representations for the field components are obtained. One of them allows separating quasistatic field and radiation one. Method of computation is developed as well. Some interesting physical effects are described. One of them is strong increase of some components of radiation field near the charge motion line (in the case of point charge). The case of a charged disc is considered as well. Prospects of use of obtained results for PWFA are discussed.

WEPPP042	Experimental Demonstration of Wakefield Effects in a 250 GHz Planar Diamond Accelerating Structure	wakefield, dipole, acceleration, electron	2816
	S.P. Antipov, J.E. Butler, C.-J. Jing, A. Kanareykin, P. Schoessow, S.S. Zuo Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York, USA W. Gai ANL, Argonne, USA
	Funding: DOE SBIR We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism. Fields produced by a first, drive, beam were used to accelerate a second, witness, electron bunch which followed the driving bunch at an adjustable distance. The energy gain of the witness bunch as a function of its separation from the drive bunch is a direct measurement of the wake potential. We also present wakefield mapping results for THz quartz structures. In this case decelerating wake inside the bunch is inferred from the drive beam energy modulation.

WEPPP072	Beam Characterization and Coherent Optical Transition Radiation Studies at the Advanced Photon Source Linac	emittance, linac, diagnostics, laser	2876
	J.C. Dooling, R.R. Lindberg, N. Sereno, C.-X. Wang ANL, Argonne, USA A.H. Lumpkin Fermilab, Batavia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357. The Advanced Photon Source facility includes a 450-MeV S-band linac with the option for injection from a photocathode (PC) rf gun. A diode-pumped, twice-frequency doubled Nd:glass regen laser (263 nm) is used with the Cu PC to generate the electron beams. Characterization of these beams and studies of the microbunching instability following beam compression in the four-dipole magnetic chicane are described. A suite of diagnostics is employed including a three-screen emittance section, a FIR coherent transition radiation autocorrelator, electron spectrometers, and an optical diagnostics end station. An energy chirp impressed on the beam is used to compress the 1-2 ps, rms bunch as it passes through the chicane. With compression, bunch lengths of 170-200 fs, rms at 450 pC are measured, and coherent optical transition radiation (COTR) due to the microbunching instability is observed. Mitigation techniques of the COTR in the beam profile diagnostics are demonstrated both spectrally and temporally. At 100 pC without compression normalized transverse emittances of 1.8 and 2.7 microns are observed in the x and y planes, in reasonable agreement with initial ASTRA simulations.

WEPPR018	Beam Experiments towards High-intensity Beams in RHIC	proton, injection, vacuum, cryogenics	2979
	C. Montag, L. A. Ahrens, M. Blaskiewicz, J.M. Brennan, K.A. Drees, W. Fischer, T. Hayes, H. Huang, K. Mernick, G. Robert-Demolaize, K.S. Smith, R. Than, P. Thieberger, K. Yip, K. Zeno, S.Y. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Proton bunch intensities in RHIC will be increased from 210¹¹ to 310¹¹ protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results will be presented.

WEPPR054	Calculation of Coherent Wiggler Radiation using Eigenfunction Expansion Method	wiggler, impedance, damping, space-charge	3048
	D. Zhou, Y.H. Chin, K. Ohmi KEK, Ibaraki, Japan G.V. Stupakov SLAC, Menlo Park, California, USA
	An analytic method originated by Y. H. Chin* was extended to calculate the electromagnetic fields and the longitudinal impedance due to coherent wiggler radiation (CWR) in a rectangular chamber. The method used dyadic Green functions based on eigenfunction expansion method in electromagnetic theory and was rigorous for the case of straight chamber. We re-derived the theory and did find the full expressions for the longitudinal impedance of a wiggler with finite length. With shielding of chamber, the CWR impedance indicated resonant properties which were not seen in the theory for CWR in free space. * Y.H. Chin, LBL-29981, 1990.

WEPPR079	Observations of Microbunching Instabilities from a THz Port at Diamond Light Source	storage-ring, synchrotron, optics, electron	3114
	W. Shields, G.E. Boorman, V. Karataev, A. Lyapin JAI, Egham, Surrey, United Kingdom R. Bartolini, A.F.D. Morgan, G. Rehm Diamond, Oxfordshire, United Kingdom
	Diamond Light source is a third generation synchrotron facility dedicated to producing radiation of outstanding brightness. Above a threshold current, the electron bunches are susceptible to the phenomenon known as the microbunching instability. This instability is characterised by the onset of radiation bursts, the wavelength of which is around one order of magnitude shorter than the bunch length. Near threshold, the bursting occurs quasi-‐periodically, however at higher currents, the bursting appears randomly. The high frequencies involved in these emissions make detection and analysis challenging. A port specifically for the investigation of mm wave emissions has recently been built at Diamond. Ultra fast Schottky Barrier Diode detectors have been installed to obtain data for only a small fraction of the bunch revolution time in an updated data acquisition system. The threshold current and subsequent evolution of the instability have been investigated.

WEPPR089	Experimental Progress: Current Filamentation Instability Study	plasma, simulation, emittance, electron	3141
	B.A. Allen, P. Muggli USC, Los Angeles, California, USA M. Babzien, M.G. Fedurin, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York, USA C. Huang LANL, Los Alamos, New Mexico, USA J.L. Martins, L.O. Silva IPFN, Lisbon, Portugal W.B. Mori UCLA, Los Angeles, California, USA
	Funding: Work supported by: National Science Foundation and US Department of Energy. Current Filamentation Instability, CFI, is of central importance for the propagation of relativistic electron beams in plasmas. CFI has potential relevance to astrophysics, magnetic field and radiation generation in the afterglow of gamma ray bursts, and inertial confinement fusion, energy transport in the fast-igniter concept. An experimental study of this instability is underway at the Accelerator Test Facility, ATF, at Brookhaven National Laboratory with the 60MeV electron beam and centimeter length capillary discharge plasma. The experimental program includes the systematic study and characterization of the instability as a function of beam (charge, transverse and longitudinal profile) and plasma (plasma density) parameters. Specifically, the transverse beam profile is measured directly at the plasma exit using optical transition radiation from a thin gold-coated silicon window. Experimental results show the reduction of the beam transverse size and the appearance of multiple (1-4) filaments and are a function of the plasma density. We will present simulation and experimental results, provide discussion of these results and outline next steps in the experiment.

THYB02	Influence of Electron Beam Parameters on Coherent Electron Cooling	electron, FEL, ion, acceleration	3213
	G. Wang, Y. Hao BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA S.D. Webb Tech-X, Boulder, Colorado, USA
	Coherent electron cooling (CeC) is promising to revolutionize the cooling of high energy hadron beams. The intricate dynamics of the CeC depends both on the local density and energy distribution of the beam. This talk should present a rigorous analytical model of the 3D processes (including diffraction) in the modulator and the FEL and describe how the theory is applied to electron beams with inhomogeneous longitudinal density- and energy distributions in the process of CeC. The SPC would like you to describe the influence of electron beam energy and current variations along the bunch length.
	Slides THYB02 [0.878 MB]

THPPC010	Beam Start-up of J-PARC Linac after the Tohoku Earthquake	linac, DTL, quadrupole, acceleration	3293
	M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan T. Maruta, A. Miura, H. Sako, J. Tamura, G.H. Wei JAEA/J-PARC, Tokai-mura, Japan
	The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant recovering effort including the realignment of most linac components, we have resumed the beam operation of J-PARC linac in December 2011. In this paper, we present the experience in the beam start-up tuning after the earthquake and the status of the linac operation thereafter.

THPPC017	Study of Physical Processes of Acceleration of Electron Bunches with Extremal Density by Means of Stored Energy in Disk Loaded Waveguide Sections	electron, linac, acceleration, electromagnetic-fields	3314
	S. Proskin, A. Kulago MEPhI, Moscow, Russia
	This presentation should consider a new theoretical method of SHF power increasing in DWLG sections. Within the presentation physical processes of the acceleration of extremely charge densities in the sections of a DWLG by the stored energy are described. As a result optimum travelling wave DWLG is taken and a simulation of acceleration processes of 20 ns electron beams is conducted.

THPPC035	Final Assembly and Testing of the MICE Superconducting Spectrometer Solenoids	solenoid, vacuum, instrumentation, focusing	3362
	S.P. Virostek, M.A. Green, T.O. Niinikoski, H. Pan, S. Prestemon LBNL, Berkeley, California, USA R. Preece STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231. The Muon Ionization Cooling Experiment (MICE) is an international effort to demonstrate the principle of ionization cooling in a segment of a realistic cooling channel using a muon beam. The experiment is sited at Rutherford Appleton Laboratory in England. A 4-tesla uniform field region at each end of the cooling channel will be provided by a pair of identical, 3-m long spectrometer solenoids. As the beam enters and exits the cooling channel, the emittance will be measured within both the upstream and downstream 400 mm diameter magnet bores. Each magnet consists of a three-coil spectrometer magnet group and a two-coil pair that matches the solenoid uniform field into the adjacent MICE cooling channel. An array of five two-stage cryocoolers and one single-stage cryocooler are used to maintain the temperature of the magnet cold mass, radiation shield and current leads. Previous testing revealed several operational and design issues related to heat leak and quench protection that have since been corrected. Details of the magnet design modifications and their final assembly as well as the results of quench training tests will be presented here.

THPPC036	The Alpha Ferrite-loaded Coaxial Resonator Cavity	cavity, damping, resonance, storage-ring	3365
	A.N. Pham, S.-Y. Lee, T.H. Luo IUCEEM, Bloomington, Indiana, USA
	Funding: Grant N00164-08-GM03 P00004 from the NSWC Crane Division, DOE Grant DE-FG02-92ER40747, and NSF Grant PHY-0852368 (IU: 48-432-31). The Advanced Electron Photon Facility (ALPHA),* is a joint collaboration between the Indiana University Center for Exploration of Energy and Matter and the Crane Naval Surface Warfare Center. The ALPHA storage ring will serve as a debuncher in single pass mode of operation. With a set of two gradient damping wigglers, the storage ring can also accumulate to achieve high charge density beams. In this report, we present the design, fabrication, and testing of the 15 MHz ferrite-loaded quarter-wave rf coaxial resonator cavity that will be utilized in the ALPHA storage ring. Topics pertaining to beam lifetime, radiation damping, ferrite-loaded transmission lines, and key cavity parameters will be discussed. * S.Y. Lee, P.E. Sokol, et al, "The ALPHA Project at IU CEEM," Proceedings of the IPAC2010. ** S.Y. Lee, et al, "A low energy electron storage ring with tunable compaction factor," RSI 78, 2007.

THPPC053	First Experience at ELBE with the New 1.3 GHz CWRF Power System Equipped with 10 kW GHz Solid State Amplifiers (SSPA)	klystron, cavity, electron, linac	3407
	H. Büttig, A. Arnold, A. Büchner, M. Justus, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig, G.S. Staats, J. Teichert HZDR, Dresden, Germany
	The superconducting CW- LINAC (1.3 GHz) of the radiation source ELBE is in permanent operation since May 2001/1/. During the winter shut-down 2011 - 1212 an upgrade program of ELBE was realized. One part of the program was to double the RF-power per cavity using two 10 kW Solid State Amplifiers in parallel per cavity. The poster gives an overview on the new RF-system and the experience gained within the first three months of operation.

THPPD011	Radiation Hard Magnets at the Paul Scherrer Institute	target, shielding, vacuum, neutron	3518
	A.L. Gabard, J.P. Duppich, D. George Paul Scherrer Institut, Villigen, Switzerland
	Radiation hard magnets have been in operation at PSI for more than 30 years. Throughout this period, extensive experience was gained regarding both the conceptual design of these magnets and their operation. Worldwide, upcoming future projects for high intensity accelerators and spallation sources will create an increasing need for radiation hard magnets. Through a presentation of the PSI main accelerator facilities, this paper describes the lessons learned over the years regarding the operation of radiation hard magnets and explains a few basic design concepts adopted by PSI based on this experience.

THPPD024	Irradiation Effects in Superconducting Magnet Materials at Low Temperature	neutron, solenoid, superconducting-magnet, target	3551
	M.Y. Yoshida, M.I. Iio, S. Mihara, T. Nakamoto, H. Nishiguchi, T. Ogitsu, M. Sugano, K. Yoshimura KEK, Ibaraki, Japan M. Aoki, T. Itahashi, Y. Kuno, A. Sato Osaka University, Osaka, Japan Y. Kuriyama, Y. Mori, B. Qin, K. Sato, Q. Xu, T. Yoshiie Kyoto University, Research Reactor Institute, Osaka, Japan
	Superconducting magnets for high intensity accelerators and particle sources are exposed to severe radiation from beam collisions and other beam losses. Neutron fluence on the superconducting magnets for the next generation projects of high energy particle physics, such as LHC upgrades and the COMET experiment at J-PARC, is expected to exceed 10²¹ n/m², which is close to the requirements on the fusion reactor magnets. Irradiation effects at low temperature in superconducting magnet materials should be reviewed to estimate the stability of the superconducting magnet system in operation and its life. The pion capture superconducting solenoids for the COMET experiment are designed with aluminum stabilized superconducting cable to reduce the nuclear heating by neutrons. Also, the heat is designed to be transferred in pure aluminum strips. Irradiation effects on the electrical conductance of aluminum stabilizer and other materials are tested at cryogenic temperature using the reactor neutrons. This paper describes the study on the irradiation effects for the magnet developments.

THPPD033	Using Permanent Magnets to Boost the Dipole Field for the High-energy LHC	permanent-magnet, dipole, cryogenics, background	3578
	F. Zimmermann CERN, Geneva, Switzerland Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan
	Funding: Work supported by the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579. The High-Energy LHC (HE-LHC) will be a new accelerator in the LHC tunnel based on novel dipole magnets, with a field up to 20 T, which are proposed to be realized by a hybrid-coil design, comprising blocks made from Nb-Ti, Nb3Sn and HTS, respectively. Without the HTS the field would be only 15 T. In this note we propose and study the possibility of replacing the inner HTS layer by (weaker) permanent magnets that might contribute a field of 1-2 T, so that the final field would reach 16-17 T. Advantages would be the lower price of permanent magnets compared with HTS magnets and their availability.

THPPD042	High Radiation Environment Nuclear Fragment Separator Dipole Magnet	dipole, quadrupole, magnet-design, target	3605
	S.A. Kahn Muons, Inc, Batavia, USA R.C. Gupta BNL, Upton, Long Island, New York, USA
	Funding: Supported in part by STTR Grant 4746 · 11SC06273 Magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) would be subjected to extremely high radiation and heat loads. Critical elements of FRIB are the dipole magnets which select the desired isotopes. Since conventional NiTi and Nb3Sn superconductors must operate at ~4.5 K, the removal of the high heat load generated in these magnets with these superconductors would be difficult. The coils for these magnets must accommodate the large curvature from the 30° bend that the magnets subtend. High temperature superconductor (HTS) have been shown to be radiation resistant and can operate in the 20-50 K temperature range where heat removal is an order of magnitude more efficient than at 4.5 K. Furthermore these dipole magnets must be removable remotely for servicing because of the extremely high radiation environment. This paper will describe the magnetic and conceptual design of these magnets.

THPPD043	Radiation-tolerant Multipole Correction Coils for FRIB	quadrupole, octupole, sextupole, multipole	3608
	S.A. Kahn Muons, Inc, Batavia, USA R.C. Gupta BNL, Upton, Long Island, New York, USA
	Multipole correction insert coils with significant field strength are required inside the large aperture superconducting quadrupole magnets in the fragment separator section of the Facility for Rare Isotope Beams (FRIB). Correction coils made with copper do not create the required field and conventional low temperature superconductors are not practical in the fragment separator magnets which will operate at 40-50 K. The correction coils should be made of HTS as the main quadrupole coils are. There is a significant advantage to using HTS in these coils as it can withstand the high radiation and heat load that will be present. This paper will describe an innovative design suitable for coils with the complex end geometry of cylindrical coils. We will look at the forces on the corrector coils from the mail quadrupole fields and anticipate possible coil distortions.

THPPD044	Fabrication and Testing of Curved Test Coil for FRIB Fragment Separator Dipole	dipole, FEL, quadrupole, proton	3611
	S.A. Kahn Muons, Inc, Batavia, USA J. Escallier, R.C. Gupta, G. Jochen, Y. Shiroyanagi BNL, Upton, Long Island, New York, USA
	Funding: Supported in part by SBIR Grant 4746 · 11SC06273 A critical element of the fragment separator region of the Facility for Rare Isotope Beams (FRIB) is the 30° dipole bend magnet. Because this magnet will be subjected to extremely high radiation and heat loads, operation at 4.5 K would not be possible. High temperature superconductors which have been shown to be radiation resistant and can operated in the 30-50 K temperature range which is more effective for heat removal. An efficient design for this magnet would make use of coils that follow the curvature of the magnet. Winding curved coils with negative curvature are difficult as the coil tends to unwind during the process. As part of an R&D effort for this magnet we are winding a ¼ scale test coil for this magnet with YBCO conductor and are testing it at 77 K. This paper will discuss the winding process and the test results of this study.

THPPD063	Zero Voltage Switching of Two-switch Flyback-Forward Converter	synchrotron, synchrotron-radiation, power-supply, photon	3656
	J.C. Huang, K.-B. Liu, Y.S. Wong NSRRC, Hsinchu, Taiwan
	The traditional pulse-width-modulated flyback converter power switch has serious electromagnetic interference (EMI) and lower conversion efficiencies problems due to the hard-switching operations. This paper produces a zero voltage switching of flyback-forward converter with an active-clamp circuit, the traditional pulse-width-modulated flyback converter with a active clamp circuit to achieve zero-voltage-switching (ZVS) at both main and auxiliary switches, the active-clamp circuit can reduce most of switching loss and voltage spikes across the switches and improve the overall efficiency of the converter. The theoretical analysis of soft switching flyback-forward converter with an active-clamp circuit is verified exactly by a prototype of 50W with 100V input voltage, 5V output voltage and 30kHz operated frequency.

THPPD084	Analysis of Beam Loss Induced Abort Kicker Instability	high-voltage, kicker, factory, electron	3713
	W. Zhang, L. A. Ahrens, W. Fischer, H. Hahn, J.-L. Mi, C. Pai, J. Sandberg, Y. Tan BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.

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MOOBA03

Development of a High-power Coherent THz Sources and THz-TDS System on the basis of a Compact Electron Linac

electron, polarization, linac, laser

37

M. Kumaki, K. Sakaue, M. Washio
RISE, Tokyo, Japan
R. Kuroda, H. Toyokawa, K. Yamada
AIST, Tsukuba, Ibaraki, Japan

The high-power terahertz time-domain spectroscopy (THz-TDS) has been developed on the basis of a compact S-band electron linac at AIST, Japan. It is strongly expected for inspection of dangerous materials in the homeland security field. The linac consists of a photocathode rf-gun, two acceleration tubes and a magnetic bunch compressor. The 40 MeV, 1 nC electron bunch is generated and compressed to less than 1 ps. THz radiations are generated in two methods with the ultra-short bunch. One is THz coherent synchrotron radiation (CSR). The other is THz coherent transition radiation (CTR). In the preliminary experiment, it was observed that the focused CTR had the donut profile in a transverse fields due to its initial radial polarization, so that it made Z-polarization. In case of the THz-TDS experiment, CTR was controlled to linearly polarization with the polarizer and focused to an EO crystal to obtain a THz temporal waveform which leads to THz spectrum with Fourier transform. The timing measurement between CTR and a probe laser was realized with OTR using a same optical photodiode. In this conference, we will describe details of our linac and results of the THz-TDS experiment.

Slides MOOBA03 [3.342 MB]

MOOBB01

Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam

emittance, cavity, electron, simulation

49

J.C.T. Thangaraj, H.T. Edwards, A.S. Johnson, A.H. Lumpkin, T.J. Maxwell, J. Ruan, J.K. Santucci, Y.-E. Sun, R.M. Thurman-Keup
Fermilab, Batavia, USA

Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.

Slides MOOBB01 [2.338 MB]

MOOBB03

An Alternative 1D Model for CSR with Chamber Shielding

impedance, shielding, vacuum, synchrotron

52

D. Zhou
KEK, Ibaraki, Japan

An alternative 1D model for modeling the longitudinal coherent synchrotron radiation (CSR) impedance is proposed. The code CSRZ* is used to calculate the CSR impedance with rectangular chamber shielding. Along the beam orbit, which may be formed by multi bends interleaved with drifts, the vacuum chamber is sliced into a series of segments. The low-frequency CSR impedance for each segment, in this case chamber shielding is significant, is obtained by numerical calculations. The high-frequency CSR impedance, in this case chamber shielding is negligible, is estimated by an analytical model**. The wake kick at each segment is computed via inverse Fourier transform of the impedance convolved the the beam spectrum. The most attractive merit of the method for CSR modeling lies in taking into account the realistic chamber shielding.
* D. Zhou, et al., To be published in Jpn. J. Appl. Phys.
** M. Borland, Phys. Rev. ST Accel. Beams 4, 070701 (2001).

Slides MOOBB03 [1.856 MB]

MOEPPB013

Simulation and Measurement of Beam Loss in the Narrow-Gap Undulator Straight Section of the Advanced Photon Source Storage Ring

undulator, simulation, vacuum, neutron

106

J.C. Dooling, M. Borland
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357.
Simulations indicate the removal of a scraper/collimator in the Sector 37 straight section (SS) of the Advanced Photon Source storage ring (SR) results in increased beam loss in the remaining narrow-gap, insertion device SS, ID4. Modeling with elegant provides loss distributions in the 5-mm aperture vacuum chamber of ID4 and includes the effects of rf system muting and quantum excitation in the bunch. The loss distributions are then used as input to a MARS model of the SS that includes undulator geometry. ID4 has been instrumented with additional monitoring to capture beam loss events, particularly beam dumps. Cerenkov detectors and fiber-optic cable bundles are used to capture temporal profiles of beam loss events. Beam dumps deliver 2600 J to the vacuum chamber and surrounding hardware including undulators. Data indicate a variety of temporal profiles occur during the beam dumps, with the shortest lasting 6 microseconds, FWHM (<2 turns). Such high power and power densities can lead to physical damage of vacuum components if not handled correctly. Touschek scattering loss is also a concern for undulator demagnetization. Comparison of modeling and measurements will be presented.

MOPPC012

Reliability and Intervention Management for the LHC

controls, status, feedback, site

148

K. Foraz, J.R. Cook, J. Coupard, B. Daudin, J. De Jonghe, F. B. Dos Santos Pedrosa, E.R. Fuentes, C. Garino, K. Golikov, S. Grillot, M.R. Jaekel, P. Sollander
CERN, Geneva, Switzerland

Since 2010, CERN has entered a mode of continuous operation of the LHC and its injectors, which implies the continuous operation of all the infrastructure and support systems. High reliability of the machines is crucial to meet the physics goals. This high reliability must be accompanied by a fast restart after programmed stops. Since 2010, an important effort has been put in place, to ease the coordination process during the programmed stops and to reinforce the management of the interventions (preparation, approval, follow-up, traceability, closure). This paper describes the difficulties from the first year related to this coordination, and the impact on operation. The tools developed for the management of the interventions, their assets and the effect on the reliability of the LHC will also be presented and discussed.

MOPPC052

Calculation of Synchrotron Radiation from High Intensity Electron Beam at eRHIC

photon, electron, synchrotron, vacuum

247

Y.C. Jing, O.V. Chubar, V. Litvinenko
BNL, Upton, Long Island, New York, USA

The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab adds an electron beam line to the existing RHIC and improves the luminosity by at least 2 orders of magnitude. It requires a high energy and high intensity electron beam. Thus the synchrotron radiation (SR) coming from the bending magnets and large quadrupoles could be penetrating the vacuum chamber and providing hazard to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity and power density distributions on the chamber wall, suggest the wall thickness required to stop the SR, calculate heat load on the chamber, and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

MOPPC084

G4beamline Code Development

space-charge, electron, collider, synchrotron

334

T.J. Roberts
Muons, Inc, Batavia, USA

Funding: Supported in part by DoE STTR grant DE-FG02-06ER86281.
G4beamline is a single-particle-tracking simulation program based on Geant4, optimized specifically for beam lines. It is currently used by several hundred physicists and designers around the world, who apply it to a diverse set of interesting problems. As it includes particle decays and interactions, it is applicable to beams for which decays and interactions are important, such as modern muon facilities that involve ionization cooling. Its description language has been designed to be both versatile and user-friendly, and the program includes high-quality visualization and histogramming capabilities. This paper discusses recent code development and new features, and some interesting applications of the program. G4beamline is an open-source program freely available at http://g4beamline.muonsinc.com

MOPPC090

Coupling Modulator Simulations into an FEL Amplifier for Coherent Electron Cooling

FEL, electron, simulation, positron

346

I.V. Pogorelov, G.I. Bell, D.L. Bruhwiler, B.T. Schwartz, S.D. Webb
Tech-X, Boulder, Colorado, USA
Y. Hao, V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the US DOE Office of Science, Office of Nuclear Physics under grant numbers DE-FG02-08ER85182 and DE-SC0000835.
Next-generation ion colliders will require effective cooling of high-energy hadron beams. Coherent electron cooling (CeC) can in principle cool relativistic hadron beams on orders-of-magnitude shorter time scales than other techniques*. Particle-in-cell (PIC) simulations of a CeC modulator with the parallel VORPAL framework generate macro-particle distributions with subtle but important phase space correlations. To couple these macro-particles into a 3D simulation code for the free-electron laser (FEL) amplifier, while retaining all details of the 6D phase space coordinates, we implemented an alternative approach based on particle-clone pairs**. Our approach allows for self-consistent treatment of shot noise and spontaneous radiation, with no need for quiet-start initialization of the FEL macro-particles' ponderomotive phase. We present results of comparing fully 3D amplifier modeling based on the particle-clone approach vs GENESIS simulations where distribution of bunching parameter was used as input. We also discuss enabling direct coupling of the VORPAL delta-f simulation output into 3D distributions of particle-clone pairs.
* V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).
** V.N. Litvinenko, "Macro-particle FEL model with self-consistent spontaneous radiation," unpublished (2002).

MOPPD064

Simulation of Double Layer Carbon Stripping Foils for ISIS Injection Upgrades

injection, simulation, scattering, proton

514

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

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

MOPPD080

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

proton, collimation, scattering, alignment

553

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

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

MOPPD083

Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

booster, kicker, injection, beam-losses

562

I.L. Rakhno, A.I. Drozhdin, N.V. Mokhov, V.I. Sidorov, I.S. Tropin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Currently a fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-5 straight section is used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With magnetic field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using two horizontal kickers in the Long-12 section. The STRUCT calculations show that using such horizontal notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV, directing 96% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. The MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.

MOPPP003

Comparison of Various Sources of Coherent THz Radiation at FLUTE

electron, synchrotron, linac, synchrotron-radiation

568

M. Schwarz, E. Huttel, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, M. Schuh, P. Wesolowski
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

The "Ferninfrarot Linac- Und Test-Experiment" FLUTE, based on a 50 MeV S-band linac with bunch compressor, is currently under construction at the KIT in Karlsruhe in order to study the production of coherent radiation in the Terahertz frequency range. The three photon generating mechanisms investigated in this paper are coherent synchrotron-, edge-, and transition radiation. For each case, we present the spectra and peak electric fields calculated from longitudinal charge distributions of a short, low charge and a long, high charge bunch. The respective bunch shapes are obtained by a detailed simulation (particle tracking) of FLUTE. We also give the expected temporal evolution of the electric field pulses.

MOPPP005

Feasibility of THz Source Based on Coherent Smith-Purcell Radiation Generated by Femtosecond Electron Bunches in Super-Radiant Regime

electron, simulation, laser, gun

574

L.G. Sukhikh, K.P. Artyomov, A. Potylitsyn
Tomsk Polytechnic University, Tomsk, Russia
A.S. Aryshev, J. Urakawa
KEK, Ibaraki, Japan
V. Karataev
JAI, Egham, Surrey, United Kingdom

Nowadays there is a big interest to THz radiation that is a promising tool for investigations in material science, in biology, medicine and other fields. THz radiation for users is mostly produced by Light Sources that are big and complex machines. Because of this there are numerous activities in research and development of a compact THz source. One of the trends is based on using different types of radiation generated in coherent regime by short electron bunches. The promising radiation mechanism is coherent Smith-Purcell radiation (CSPR) that has monochromatic angular distribution and that is generated while the bunch travels in a vicinity of a grating. In this report we present simulated characteristics of frequency-locked coherent Smith-Purcell radiation (super-radiant regime) generated by a train of short (hundreds of femtosecond) 10 MeV electron bunches with THz spacing. The simulations are performed for different grating profiles and parameters using existing CSPR models and Particle-in-Cell simulation code. We also discuss the feasibility of the THz source based on CSPR and status of the experiment that is prepared at LUCX facility at KEK after the upgrade.

MOPPP006

Inverse Cherenkov Radiation based on Smith-Purcell Effect

electron, linac, gun, laser

577

K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan
M. Hangyo
ILE Osaka, Suita, Japan
R. Kuroda, H. Toyokawa
AIST, Tsukuba, Ibaraki, Japan

Inverse Cherenkov radiation based on Smith-Purcell effect using metamaterial was investigated. A metallic grating and picosecond electron bunch of 27 MeV beam energy from a thermionic DC gun and linac were used for the inverse radiation. The frequency spectra in terahertz (THz) range were measured by a Michelson interferometer experimentally. Peaks of discrete component in the spectra shifted continuously according to the radiation angles, e. g. discrete peak changing from 0.117 to 0.085 THz with radiation angle along the electron bunch from 102 to 134 degree (backward) using a 2-mm-period metallic grating. In this presentation, experiment using another electron bunch generated by a photocathode RF gun linac will be reported.

MOPPP007

High-intensity Monochromatic Cherenkov Radiation in THz Range by Femtosecond Electron Bunches in Impurity-doped Semiconductor Tube

electron, plasma, wakefield, vacuum

580

A. Ogata, K. Kan, T. Kondoh, K. Norizawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

A novel method to generate high-power THz radiation is proposed and the preliminary experiments are conducted. If a beam with a bunch length on the order of 100 fs is injected into an electron–hole plasma of a semiconductor with a plasma frequency on the order of THz, THz wake fields are coherently generated. If the beam moves on the axis of a hollow tube covered by a metal, the frequency spectrum of the radiation is composed of discrete components. Monochromatic radiation is obtained by making only the lowest frequency component coherent. In the preliminary experiments using mm-sized dielectric tubes, the radiation spectra, which was driven by electron bunches of 200fs/27 MeV, were measured directly by a Michelson interferometer and bolometer. Peaks at frequencies of 0.09 and 0.14 THz of transverse magnetic (TM) modes, which corresponded to TM03 and TM04, were observed. The other higher modes, e. g. 0.36 (TM09) and 0.40 THz (TM010), were also observed successfully at a bunch charge of 15 pC, which decreased the electron bunch length.

MOPPP010

Investigation of CSR Effect for Femtosecond Electron Bunches in an Isochronous Accumulator Ring

simulation, lattice, electron, linac

589

N.Y. Huang, H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, K. Takahashi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Coherent synchrotron radiation (CSR) from a novel isochronous ring is a candidate for light source that provides THz radiation with high average flux. A compact isochronous accumulator ring (IAR) for the maximum beam energy of 54 MeV has been designed so as to eliminate the 0th order momentum compaction factor, and the 1st order of it is mostly compensated. In addition, the path length deviation due to betatron motion is mostly compensated in a cell. Though there is no RF cavity in IAR, the injected beam may circulate for certain number of turns. Multi experimental stations can be allocated like synchrotron radiation facilities. However, it has been well known that instability due to the CSR wake field is an issue for the beam stability in the ring operated at low alpha mode. Therefore, a study for effects of the CSR wake on the bunch length and shape in IAR has been in progress. It has turned out that the maximum longitudinal field strength created by CSR would be ~ 0.15 MV/m for the case of 100 fs Gaussian bunch, which is considerably an intense field. To protect the bunch shape from the CSR wake, further study is definitely required.

MOPPP012

Experimental Observation of Energy Modulation in Electron Beams Passing through Terahertz Dielectric Wakefield Structures

wakefield, bunching, FEL, acceleration

595

S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, USA
B.C. Jiang
SINAP, Shanghai, People's Republic of China

Funding: DOE SBIR.
We report observation of a strong wakefield induced energy modulation in an energy-chirped electron bunch passing through a terahertz dielectric-lined waveguide. This modulation can be effectively converted into a spatial modulation by means of a chicane, forming micro-bunches (density modulation) with a periodicity of 0.5 - 1 picosecond, hence capable of driving coherent THz radiation. The experimental results agree well with theoretical predictions.

MOPPP018

Construction Status of the Compact ERL

linac, cryomodule, gun, emittance

607

S. Sakanaka, H. Kawata, Y. Kobayashi, N. Nakamura
KEK, Ibaraki, Japan
R. Hajima
JAEA, Ibaraki-ken, Japan

Future synchrotron light source based on a 3-GeV energy recovery linac (ERL) is under proposal at KEK, and we are conducting extensive R&D efforts. To demonstrate reliable operations of key components for the ERL project, as well as to demonstrate the generation of ultra-low emittance beams, we are constructing the Compact ERL (cERL). The cERL will also be used to demonstrate the generation of brilliant gamma-rays that is useful for analyzing radioisotopes. Key components, such as a photocathode DC gun, both cryomodules for the injector and the main linac, rf sources, magnets, and beam instrumentations, are under fabrication. Construction of radiation shielding for the cERL started in December, 2011. We report up-to-date status of the cERL.

MOPPP022

ALICE: Status, Developments and Scientific Programme

FEL, gun, acceleration, cryomodule

613

Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

ALICE (Accelerators and Lasers In Combined Experiments) is a multifunctional ERL based R&D facility that operates in various regimes, both energy recovery and non energy recovery, depending on the project undertaken (beam energy 10-28MeV, bunch charge 20-100pC, train length from a single bunch to 100us). In early 2012, the DC HV photoinjector gun is expected to begin operation at nominal 350kV and a new cryomodule, a result of a wide international collaboration, will be installed and commissioned on ALICE. The improvements in beam dynamics and the overall beam quality will be discussed in this paper. The overview of the ALICE scientific programme including IR-FEL lasing and its application for scanning near field optical microscopy, generation and applications of coherent broadband THz radiation for life sciences and solid state physics, studies of the first non-scaling FFAG EMMA for which ALICE serves as an injector and accelerator physics research will also be presented.

MOPPP032

Longitudinal Phase Space Studies at the PITZ Facility

electron, laser, gun, FEL

631

M. Mahgoub, J.W. Bähr, H.-J. Grabosch, M. Groß, L. Hakobyan, G. Klemz, G. Kourkafas, M. Krasilnikov, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, K. Rosbach, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
I.I. Isaev
MEPhI, Moscow, Russia
Ye. Ivanisenko
IERT, Kharkov, Ukraine
M. Khojoyan
ANSL, Yerevan, Armenia
J. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China
B. Marchetti
INFN-Roma II, Roma, Italy
D. Richter
HZB, Berlin, Germany
J. Rönsch-Schulenburg
Uni HH, Hamburg, Germany

Photoinjectors are a cornerstone for short-wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL in Hamburg, Germany. The Photo Injector Test facility at DESY, location Zeuthen (PITZ), was built to develop and optimize such photoinjectors. The PITZ facility is capable of generating long trains of electron bunches, which can be accelerated up to ~25 MeV/c. Studying and optimizing the longitudinal properties of the electron bunch is an important topic at PITZ. A streak system consisting of Silica Aerogel radiators, optical transition radiation (OTR) screens, optical transmission line, and a streak camera is used to study the longitudinal properties with an accuracy of some ps. Due to the high radiation level in the facility, many of the lenses in the optical transmission line have turned brown, reducing the efficiency of the system. Some of the lenses were recovered by baking them up to 180°C. In contrast, few sensitive objective lenses can not be baked, rather they were recovered via exposure to infrared radiation with the proper wave length. An overview of the system, the difficulties, and the modifications needed to overcome the radiation effects are presented.

MOPPP072

Performance of APPLE-II Type Quasi-Periodic Undulator at HiSOR

undulator, polarization, electron, photon

729

S. Sasaki, M. Arita, K. Goto, A. Miyamoto, T. Okuda
HSRC, Higashi-Hiroshima, Japan

A 1.8-m-long 78-mm-period quasi-periodic APLPE-II undulator was installed in the 700-MeV HiSOR storage ring of Hiroshima Synchrotron Radiation Center. At 23-mm nominal minimum gap, the fundamental photon energies are 3.1 eV, 6.5 eV, and 4.8 eV for horizontal linear, vertical linear, and circular polarization, respectively. The photon energies of observed fundamental and higher harmonic radiations are in good agreement with those of model calculations using measured undulator field and the HiSOR beam parameters. Also, observed flux thorough a slit and a grating monochromator was more than twice larger than that from previously installed 100-mm-period helical undulator for the whole range of radiation spectra. The feedforward COD correction was done to avoid the intensity fluctuation of photon beam in other BM beamlines due to the gap and phase motion of undulator. No fatal effect on the stored electron beam by installing the undulator was observed though a slight beam size change was observed at the minimum gap.

MOPPP074

Magnetic Field Measurement for a THz Undulator Using the Vibrating Wire Method

undulator, electron, laser, resonance

732

S. Kashiwagi, H. Hama, F. Hinode, M. Kawai, X. Li, T. Muto, K. Nanbu, Y. Tanaka
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Funding: This work is supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (S), Contract #20226003.
We constructed the undulator that is a basically a Halbach planer type for a generation of intense coherent terahertz radiation from the very short electron bunch. The period length of the undulator and the number of periods are 100 mm and 25, respectively. Its maximum magnetic field is 0.41 T and the K-value is 3.82 with 54 mm gap. The vibrating wire method is studied to measure the periodic magnetic field of the undulator. By measuring amplitudes and phases of standing waves excited on the wire by the Lorentz force between AC current and magnetic field, we can reconstruct the magnetic field distribution along the wire. The theoretical analysis has been performed for the THz undulator and derived a relation between a reproducibility of undulator field and the number of the harmonic mode to use for the reconstruction. A model experiment was demonstrated using 20cm wire and one pair of permanent magnet block. The theoretical study and the results of model experiment using the vibrating wire method will be shown in this conference.

MOPPP075

The Research on Magnetic Properties of Magnet for SSRF Cryogenic Permanent Magnet Undulator

cryogenics, undulator, permanent-magnet, synchrotron

735

Y.Z. He, L. Wang, Q.G. Zhou
SINAP, Shanghai, People's Republic of China

The temperature coefficient of Br and Hci of Nd2Fe14B and Pr2Fe14B permanent magnet are about -0.1 K-1 and -0.6 K-1 respectively, the higher Br and Hci can be obtained at low temperature. By this theory, a cryogenic permanent magnet undulator(CPMU) may be designed, the maximum magnetic field and the Hci of permanent magnet increased 10-50% and 300-500% respectively, compared with the conventional undulators, the higher brightness X-rays and the more resistance to radiation of undulators can be obtained. The Pr2Fe14B permanent magnet has better potential magnetic properties than the Nd2Fe14B permanent magnet at low temperature for having no spin reorientation phenomenon. The permanent magnets are key “heart” magnetic components for cryogenic permanent magnet undulator, since January 2012, the research plan on magnetic properties of domestic permanent magnet for SSRF cryogenic permanent magnet undulator at low temperature by the support of Shanghai and Nation Nature science funds be started, the paper introduced research status of the item.

MOPPP076

Design Considerations for a Hybrid Undulator Applied in a Terahertz FEL Oscillator

undulator, FEL, electron, cavity

738

B. Qin, M. Fan, Y.Q. Xiong
Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China
P. Tan
HUST, Wuhan, People's Republic of China

A planer undulator using hybrid permanent magnet scheme was designed for a FEL based 1THz~3THz radiation source. The influence of the undulator magnetic field errors, including peak field shift and field integrals errors, on the coherent radiation performance such as the gain per pass is investigated. And finally specifications of the undulator are determined.

MOPPP077

Heat Load Budget on TPS Undulator in Vacuum

undulator, synchrotron, synchrotron-radiation, vacuum

741

J.C. Huang, J. Chen, C.-S. Hwang, F.-Y. Lin, Y.T. Yu
NSRRC, Hsinchu, Taiwan

The performance of an insertion device is limited by the magnet gap because a small gap affects the dynamic aperture and results in a short life time of the beam. An in-vacuum undulator is designed to have no vacuum chamber between the magnet arrays so to allow the entire magnet gap to be fully used for the dynamic aperture. An in-vacuum undulator can optimally minimize the gap to achieve continuous energy spectra. One problem of an undulator with a small gap is resistive wall heating by the image current. The heat load depends strongly on the injected mode in the storage ring; injection of multiple bunches might deteriorate the thermal performance for the magnet array. In this paper, we present a calculation of the heat load budget for a magnet array of an in-vacuum undulator of Taiwan Photon Source (TPS).

MOPPP078

Status of the First Planar Superconducting Undulator for the Advanced Photon Source

undulator, photon, controls, status

744

Y. Ivanyushenkov, M. Abliz, K.D. Boerste, T.W. Buffington, C.L. Doose, J.D. Fuerst, Q.B. Hasse, M. Kasa, S.H. Kim, R. Kustom, E.R. Moog, D. Skiadopoulos, E. Trakhtenberg, I. Vasserman
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Superconducting technology offers the possibility of building short-period undulators for synchrotron light sources. Such undulators will deliver higher fluxes at higher photon energies to the light source user community. The Advanced Photon Source (APS) team is building the first superconducting planar undulator to be installed in the APS storage ring. The current status of the project is presented in this paper.

MOPPP085

Single Electron Dynamic of Microwave Undulator

electron, undulator, FEL, free-electron-laser

753

C. Chang, J. Neilson, C. Pellegrini, M. Shumail, S.G. Tantawi
SLAC, Menlo Park, California, USA

The analytical and numerical calculations for the dynamic of single electron and beam in RF undulator have been conducted and compared. The transverse and longitudinal velocity, trajectory, energy variation, and the spontaneous radiation are studied. It is found that the forward and backward wave (FW/BW) components have different contribution on electron motion and radiation, most of the energy spread comes from FW component, in other words, the effect of FW on modulating the electron energy is much stronger than that of BW for the same undulating-amplitude value, which mechanism has been analyzed.

MOPPP090

Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings

undulator, electron, vacuum, photon

765

O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe
BNL, Upton, Long Island, New York, USA
J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: US DOE, Contract No. DE-AC02-98CH10886.
We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations.

MOPPP091

Recent Developments at the DELTA THz Beamline

laser, electron, storage-ring, undulator

768

P. Ungelenk, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, A. Schick, M. Zeinalzadeh
DELTA, Dortmund, Germany

Funding: Work supported by DFG, BMBF, and by the Federal State NRW.
During 2011, a new dedicated THz beamline has been constructed and commissioned at DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University. This beamline enables extracting and detecting coherent THz pulses caused by a laser-induced density modulation of the electron bunches. Ongoing experiments aim at characterizing the THz radiation as well as investigating the evolution of the density modulation over subsequent revolutions following the initial laser-electron interaction in an undulator.

MOPPR011

A New Diagnostic Beamline at ELSA

synchrotron, synchrotron-radiation, diagnostics, electron

795

S. Zander, F. Frommberger, P. Hänisch, W. Hillert, B. Neff
ELSA, Bonn, Germany

Funding: Funded by the DFG within the SFB / TR 16.
At the Electron Stretcher Facility (ELSA), a new synchrotron light diagnostic Beamline has been installed in order to perform high resolution, transversal and longitudinal beam profile measurements by analyzing the emitted synchrotron light. For this purpose, the main deflecting AL mirror selects a wide range of wavelengths from 200–800 nm out of the whole synchrotron spectrum. The setup of the beamline and its relevant components will be presented.

MOPPR014

Installation and Test of a Beam Loss Monitor System for the S-DALINAC

electron, controls, monitoring, background

804

R. Stegmann, U. Bonnes, C. Burandt, R. Eichhorn, F. Hug, L.E. Jürgensen, N. Pietralla
TU Darmstadt, Darmstadt, Germany
D. Proft
ELSA, Bonn, Germany

Funding: This work is supported by the DFG through SFB 634.
The superconducting Darmstadt linear accelarator S-DALINAC is designed for accelerating electrons up to energies of 130 MeV for measurements in nuclear physics at small momentum transfers. For the purpose of machine protection and in order to increase reliability and efficiency an efficient tool for on-line measurements of beam losses down to electron energies of 1 MeV is desirable. Therefore a system of beam-loss monitors has been developed, installed, and tested. The system consists of commercially availiable PIN-diods and newly developed electronics. Implementation in the S-DALINAC's control system is done via EPICS IOC. We will report on the setup of the beam-loss monitoring system and on its initial performance in first tests.

MOPPR019

Beam Profile Imaging Based on Backward Transition Radiation in the Extreme Ultraviolet Region

electron, target, FEL, diagnostics

819

L.G. Sukhikh, S. Bajt, G. Kube
DESY, Hamburg, Germany
W. Lauth
IKP, Mainz, Germany
Yu.A. Popov, A. Potylitsyn
Tomsk Polytechnic University, Tomsk, Russia

Backward transition radiation (BTR) in the optical spectral region is widely used for beam profile diagnostics in modern electron linacs. However, the experience from linac based light sources shows that BTR diagnostics might fail because of coherence effects in the emission process. To overcome this problem of coherent emission it was proposed to use BTR in the extreme ultraviolet (EUV) region*, and measurements of the angular EUV BTR distribution were presented in Ref. **. This contribution summarizes the results of a beam profile imaging experiment using EUV BTR. The experiment was carried out using the 855 MeV electron beam of the Mainz Microtron MAMI. EUV BTR was generated at a molybdenum target deposited onto a silicon substrate, and imaging was realized using a spherical multilayer mirror which was optimized for a wavelength of 19 nm. Preliminary results will be presented and compared to ordinary optical BTR imaging together with a discussion of future possibilities of the proposed diagnostic method.
* L.G. Sukhikh et al., Nucl. Instrum. Methods A623, 567 (2010).
** L.G. Sukhikh et al., Proc. of DIPAC-2011, Hamburg (Germany), 544 (2011).

MOPPR024

Non-intercepting Emittance Measurements by means of Optical Diffraction Radiation Interference for High Brightness Electron Beam

quadrupole, electron, emittance, target

831

A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
V. Balandin, N. Golubeva, K. Honkavaara, G. Kube
DESY, Hamburg, Germany
M. Castellano, E. Chiadroni
INFN/LNF, Frascati (Roma), Italy
L. Catani
INFN-Roma II, Roma, Italy

Conventional intercepting transverse electron beam diagnostics, e.g. based on Optical Transition Radiation (OTR), cannot tolerate high power beams without remarkable mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR) is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitations of this method is the low signal to noise ratio, mainly due to the unavoidable synchrotron radiation background. This problem can be overcome by using ODRI (Optical Diffraction Radiation Interference). In this case the beam goes through two slits opened on metallic foils, placed in a distance shorter than the radiation formation zone. Thanks to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. Here we report the first measurements, carried out at FLASH (DESY, Germany), of the beam emittance using ODRI. Our results demonstrate the unique potential of this technique.

MOPPR050

Design and Analysis of EPU XBPM in TPS

undulator, photon, synchrotron, synchrotron-radiation

894

A. Sheng, C.M. Cheng, C.K. Kuan
NSRRC, Hsinchu, Taiwan
D. Shu
ANL, Argonne, USA

Several planer and elliptical polarized undulators (EPU) beam lines have been proposed and are to be built for Taiwan Photon Source (TPS) in National Synchrotron Research Center (NSRRC). Due to its complexity, with changing of vertical as well as horizontal deflection parameters (Kx and Ky), one finds that regular diamond bladed photon beam position monitor (XBPM) would not be sufficient to detect the center location of the undulator. A new conceptual design of EPU XBPM has been analyzed both in thermal as well as photon aspects. A prototype by taking advantage of fluorescent some of the diamond detectors has been designed and implemented in Taiwan Light Source (TLS) for testing. Some analysis and design scenarios are presented in this paper.

MOPPR054

Beam Size Measurement at Siam Photon Source Storage Ring

synchrotron, storage-ring, monitoring, photon

906

P. Sudmuang, N. Deethae, P. Klysubun, S. Krainara, T. Poolampong, K. Sitisart, N. Suradet
SLRI, Nakhon Ratchasima, Thailand

Synchrotron radiation interferometer and direct imaging setups have been installed and subsequently utilized to investigate transverse beam profile at the Siam Photon Source (SPS). Details of the optical setup as well as the beam sizes determined from the measurement will be presented. Comparison between the measured and theoretical values as established by linear optics calibration will be made and discussed. In order to demonstrate the beam profiling capability of the interferometer and direct imaging systems, measurements with different operating parameters have been carried out and the results will be presented as well.

MOPPR063

Exploiting the Undesired: Beam-gas Interactions in the LHC

vacuum, simulation, proton, quadrupole

927

R. Versaci, V. Baglin, M. Brugger
CERN, Geneva, Switzerland
A. Mereghetti
UMAN, Manchester, United Kingdom

The vacuum inside the LHC pipes has a key role in correct operation of the accelerator. The interaction of the beam with residual gas in the pipes can lead to the loss of the beam itself and damage accelerator components. Nevertheless, beam-gas interactions can be exploited to indirectly measure the gas pressure inside the beam pipe, detecting the secondaries produced. The showers generated are detected by Beam Loss Monitors, whose signals depend on the gas pressure. This technique would also allow to punctually measure the gas pressure in sections of the accelerator where vacuum gauges are not frequent, such as the arcs. The problem has been addressed by means of FLUKA simulations and the results have been benchmarked with direct measurements performed in the LHC in 2011.

MOPPR071

Initial Results of Transverse Beam Profile Measurements Using a LYSO:Ce Crystal

diagnostics, electron, controls, laser

951

A.S. Johnson, A.H. Lumpkin, T.J. Maxwell, J. Ruan, J.K. Santucci, C.C. Tan, R.M. Thurman-Keup, M. Wendt
Fermilab, Batavia, USA

A prototype transverse beam profile monitor for eventual use at the Advanced Superconducting Test Accelerator (ASTA) has been tested at the Fermilab A0 Photoinjector. Results from low-charge (20 pC) studies indicate that a LYSO:Ce scintillator will be a viable replacement for a YAG:Ce scintillator when using intercepting radiation convertor screens for beam profiling. We will also describe the planned implementation of LYSO:Ce crystals to mitigate the coherent optical transition radiation due to the microbunching instability through the use of band-pass filters and specially timed cameras.

MOPPR077

ION CHAMBERS AND HALO RINGS FOR LOSS DETECTION AT FRIB

ion, linac, cryomodule, simulation

969

Z. Liu
IUCF, Bloomington, Indiana, USA
D. Georgobiani, M.J. Johnson, M. Leitner, R.M. Ronningen, T. Russo, M. Shuptar, R.C. Webber, J. Wei, X. Wu, Y. Yamazaki, Y. Zhang, Q. Zhao
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Unlike the high energy proton machines, our radiation transport simulation results show that it will be difficult to use traditional BLMs to detect beam losses for FRIB linac, not only due to the low radiation levels from low energy heavy ion beams, but also resulted by the cross talk effect from one part of the machine to another in the folded machine geometry. A device called “Halo Ring” is introduced as a component of the BLM system to substitute the traditional ion chamber in those regions.

MOPPR090

Progress Report on Development of a High Resolution Transverse Diagnostic based on Fiber Optics

electron, diagnostics, photon, optics

996

R. Tikhoplav, R.B. Agustsson, G. Andonian, A.Y. Murokh, S. Wu
RadiaBeam, Santa Monica, USA
R.K. Li, P. Musumeci, C.M. Scoby
UCLA, Los Angeles, California, USA

A beam profile monitor utilizing the technological advances in fiber optic manufacturing to obtain micron level resolution is under development at RadiaBeam Technologies. This fiber-optic profiling device would provide a low cost, turn-key solution with nominal operational supervision and requires minimal beamline real estate. Preliminary results of Cherenkov light generation in fiber is presented.

TUOAB02

Investigation of the Use of Silicon, Diamond and Liquid Helium Detectors for Beam Loss Measurements at 2 Kelvin

cryogenics, proton, electron, interaction-region

1080

C. Kurfuerst, B. Dehning, W.T. Eisel, M. Sapinski
CERN, Geneva, Switzerland
V. Eremin
IOFFE, St. Petersburg, Russia
C. Fabjan
HEPHY, Wien, Austria

At the triplet magnets, close to the interaction regions of the LHC, the current Beam Loss Monitoring (BLM) system is very sensitive to the debris from the collisions. For future beams with higher energy and higher luminosity this will lead to a situation in which the BLM system can no longer distinguish between these interaction products and quench-provoking beam losses from the primary proton beams. The solution investigated is to locate the detectors as close as possible to the superconducting coil, i.e. the element to be protected. This means putting detectors inside the cold mass of the superconducting magnets at 1.9 K. As possible candidates for such loss monitors, diamond, silicon and a liquid helium chamber have been tested in a proton beam at liquid helium temperatures. The initial promising results from these tests will be presented and discussed in this contribution.

Slides TUOAB02 [3.412 MB]

TUOBB03

Status of the FERMI@Elettra Project

FEL, laser, electron, photon

1092

M. Svandrlik, E. Allaria, L. Badano, S. Bassanese, F. Bencivenga, E. Busetto, C. Callegari, F. Capotondi, D. Castronovo, M. Coreno, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, A.A. Demidovich, M. Di Fraia, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, P. Furlan Radivo, G. Gaio, L. Giannessi, R. Gobessi, C. Grazioli, E. Karantzoulis, M. Kiskinova, M. Lonza, B. Mahieu, C. Masciovecchio, S. Noè, F. Parmigiani, G. Penco, E. Principi, F. Rossi, L. Rumiz, C. Scafuri, S. Spampinati, C. Spezzani, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, M. Zaccaria, D. Zangrando, M. Zangrando
ELETTRA, Basovizza, Italy

Funding: The work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3.
The FERMI@Elettra seeded Free Electron Laser has provided the first photons to the experimental stations during 2011. The first FEL line in operation is FEL-1, covering the wavelength range between 100 nm and 20 nm. The facility will be opened to users by the end of 2012. In the meantime the installation of the second FEL line, FEL-2 covering the higher energy range down to 4 nm, is progressing on schedule and first tests have started. A description of the status of the project is presented here.

Slides TUOBB03 [5.316 MB]

TUEPPB009

First Measurements of the FACET Coherent Terahertz Radiation Source

electron, diagnostics, photon, insertion

1134

Z. Wu, E. Adli, A.S. Fisher, M.J. Hogan, H. Loos
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
The Facility for Accelerator science and Experimental Tests (FACET) at SLAC provides a high peak current, sub-ps bunched beam that is ideal for THz photon generation via coherent transition radiation. This paper presents preliminary characterization of the THz pulses generated by FACET electron beam. A one-micron thick Ti foil has been inserted into the beam path and the radiated photons collected. Michelson spectroscopy yields frequency content spanning from 0.25 THz to 2.3 THz and peaked at around 0.5 THz. Multiple scans at different bunch compression show a monotonic increase of the peak radiation frequency as the electron bunch gets shorter. Using the Kramers-Kronig relation, the temporal profile of the THz pulse is reconstructed from the power spectrum indicating a ~4 picosecond main pulse followed by a long oscillating tail due to the water absorption lines and detector response. Knife-edge scans measure a 4.4 mm x 4.8 mm transverse spot size at the focal point of the THz optical path. The total collected energy per pulse is 0.69 mJ measured by a Joulemeter. Fitting this total energy to the spatiotemporal profile of the THz pulse yields peak e-field amplitude of 1.5 MV/cm.

TUEPPB010

Oscillator Seeding of a High Gain Harmonic Generation FEL in a Radiator-first Configuration

FEL, electron, laser, bunching

1137

P.R. Gandhi, J.S. Wurtele
UCB, Berkeley, California, USA
G. Penn, M.W. Reinsch
LBNL, Berkeley, California, USA

A longitudinally coherent X-ray pulse from a high repetition rate free electron laser (FEL) is desired for a wide variety of experimental applications. However, generating such a pulse with a repetition rate greater than ~1 MHz is a significant challenge. The desired high rep rate sources, primarily high harmonic generation with intense lasers in gases or plasmas, do not exist now, and, for the multi-MHz bunch trains that superconducting accelerators can potentially produce, are likely not feasible with current technology. In this paper, we propose to place an oscillator downstream of a radiator. The oscillator generates radiation that is used as a seed for a high gain harmonic generation (HGHG) FEL which is upstream of the oscillator. For the first few pulses the oscillator builds up power and, until power is built up, the radiator has no HGHG seed. As power in the oscillator saturates, the HGHG is seeded and power is produced. The dynamics and stability of this radiator-first scheme is explored analytically and numerically. A single-pass map is derived using a semi-analytic model for FEL gain and saturation. Iteration of the map is shown to be in good agreement with simulations.

TUEPPB013

Development of an Advanced Computational Tool for Start-to-End Modeling of Next Generation Light Sources

electron, simulation, wakefield, undulator

1143

J. Qiang, J.N. Corlett, C.E. Mitchell, C. F. Papadopoulos, G. Penn, R.D. Ryne, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Start-to-end simulation plays an important role in designing next generation light sources. In this paper, we present recent progress in further development and application of the parallel beam dynamics code, IMPACT, towards the fully start-to-end, multi-physics simulation of a next generation X-ray FEL light source. We will discuss numerical methods and physical models used in the simulation. We will also present some preliminary simulation results of a beam transporting through photoinjector, beam delivery system, and FEL beamlines.

TUEPPB015

Generation of Narrow-Band Coherent Tunable Terahertz Radiation using a Laser-Modulated Electron Beam

laser, electron, undulator, bunching

1146

M.P. Dunning, C. Hast, E. Hemsing, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, Z.M. Szalata, D.R. Walz, S.P. Weathersby, D. Xiang
SLAC, Menlo Park, California, USA

Funding: Work supported by US DOE contract DE-AC02-76SF00515.
The technical layout and initial results of an experiment to generate narrow-band, coherent, tunable terahertz (THz) radiation through the down-conversion of the frequency of optical lasers using a laser-modulated electron beam are described. In this experiment a 120 MeV electron beam is first energy modulated by two lasers with different wavelengths. After passing through a dispersive section, the energy modulation is converted into a density modulation at THz frequencies. This density-modulated beam will be used to generate narrow-band THz radiation using a coherent transition radiator inserted into the beam path. The central frequency of the THz radiation can be tuned by varying the wavelength of one of the two lasers or the energy chirp of the electron beam. The experiment is being performed at the NLCTA at SLAC, and will utilize the existing Echo-7 beamline, where echo-enabled harmonic generation (EEHG) was recently demonstrated.

TUPPC034

Preparation of SLS for IBS Measurements

emittance, diagnostics, optics, impedance

1233

N. Milas, M. Böge, A. Streun
PSI, Villigen, Switzerland
M. Aiba, A. Lüdeke, A. Saa Hernandez
Paul Scherrer Institut, Villigen, Switzerland
F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

It is planned to use the SLS for testing damping ring issues related to linear colliders. One aspect is the study of Intra-Beam Scattering (IBS) effects, which are a limiting factor for ultra-low emittance rings. In this paper we present the setup and characterization of a new mode of operation in which the SLS runs at lower energy (1.57 GeV) with a natural emittance of 2.4 nm rad. This is much smaller than that at the nominal energy (2.41 GeV) and should make IBS effects more easily visible. In order to be able to observe IBS a careful setup is required: Optics measurement and correction as well as measurements of the bunch natural energy spread and the onset of turbulent bunch lengthening. Also, a detailed discussion on the available diagnostics and their limitations are shown and finally some preliminary results of beam emittance measurements, in all three planes, as a function of single bunch current are presented.

TUPPC074

Study of Resonance Driving Term in Electron Storage Rings

damping, resonance, storage-ring, electron

1344

G. Liu, W. Li, L. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

The resonance driving term (RDT) is useful to analyze and optimize the nonlinear performance of the storage ring. In addition to analytical calculation of RDT, experimental measurement of RDT has been made in some proton storage rings based on turn-by-turn BPM data. For electron storage rings, the analysis is more complicated due to decoherence effects and strong radiation damping. The relation between spectral decomposition of BPM data and RDT is derived and validated using beam numerical tracking data in this paper.

TUPPD014

To the Ionization Cooling in a RF Cavity with Absorber

cavity, scattering, focusing, emittance

1437

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

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

TUPPD024

HIGH-INTENSITY LOW-ENERGY POSITRON SOURCE AT JEFFERSON LABORATORY

target, positron, simulation, solenoid

1461

S. Golge, B. Vlahovic
NCCU, Durham, USA
B. Wojtsekhowski
JLAB, Newport News, Virginia, USA

We present a novel concept of a low-energy e⁺ source with projected intensity on the order of 10¹⁰ slow e+/s. The key components of this concept are a continuous wave e^- beam, a rotating positron-production target, a synchronized raster/anti-raster, a transport channel, and extraction of e⁺ into a field-free area through a magnetic plug for moderation in a cryogenic solid. Components were designed in the framework of GEANT4-based (G4beamline) Monte Carlo simulation and TOSCA magnetic field calculation codes. Experimental data to demonstrate the effectiveness of the magnetic plug is presented.

TUPPD025

REVIEWOF LOW-ENERGY POSITRON BEAM FACILITIES

positron, target, linac, neutron

1464

S. Golge, B. Vlahovic
NCCU, Durham, USA

Positrons are produced by processes such as positive beta decay from radioactive isotopes, in nuclear reactor cores from both in-situ radioisotope radiation and pair production, and by accelerator driven beams hitting a converter target. The purpose of this paper is to review some of the prominent existing low-energy e⁺ facilities.

TUPPD055

Characterization of ps-spaced Comb Beams at SPARC

simulation, linac, bunching, laser

1527

A. Mostacci
URLS, Rome, Italy
A. Bacci, A.R. Rossi
Istituto Nazionale di Fisica Nucleare, Milano, Italy
M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

SPARC in Frascati is a high brightness photo-injector used to explore advanced beam manipulation techniques. Sub-picosecond, high brightness electron bunch trains (the so called comb beam) can be generated illuminating the cathode of a RF photoinjector with a laser pulse train and via velocity bunching technique. In this paper different aspects of the physics of this advanced beam manipulation technique are discussed combining simulation and measurements. Beam dynamics numerical macroparticle simulations have been compared with the experimental results for model validation; they allow to gain insights on the beam evolution highlighting several aspects which can not be measured. In particular, we focus on the train evolution in the linac sections and in the dog-leg line up to the THz station and on the effective rms length of the single pulses within the train when it becomes shorter than the resolution.

TUPPP004

Low-alpha Operation for the SOLEIL Storage Ring

optics, injection, coupling, photon

1608

M.-A. Tordeux, J. Barros, A. Bence, P. Brunelle, N. Hubert, M. Labat, P. Lebasque, A. Nadji, L.S. Nadolski, J.-P. Pollina
SOLEIL, Gif-sur-Yvette, France
C. Evain
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France

The low momentum compaction factor (alpha) operation has been recently established on the SOLEIL Storage Ring. Both time resolved X-ray and THz radiation user communities are taking benefit from a hybrid filling pattern with a 4.7 ps RMS bunch length. At a value of 1.7 10^-5 (nominal alpha /25) and a current per bunch of 65 μA, stable THz radiation is produced in the range of 8 - 20 cm^-1 (measurements and comparison with Coherent Synchrotron Radiation (CSR) modeling are reported elsewhere*, **). Several low-alpha optics have been investigated and the optics presented at IPAC’11 has been selected for the operation. This paper presents the comprehensive experimental characterization of this optics. Specificities of the low-alpha operation, driven by the very demanding user experiments, are reviewed: closed orbit stability issues, extremely tight injected current step when refilling which implies a specific Linac tuning, low current diagnostics optimization, short bunch measurements, insertion devices effect on the CSR characteristics and radiation safety aspects justified by beam losses at injection.
* C. Evain, A. Loulergue et al., this conference.
** E. Roussel et al., this conference.

TUPPP008

Recent Results From the Short-Pulse Facility at the DELTA Storage Ring

laser, electron, undulator, synchrotron

1617

A. Schick, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, P. Ungelenk, M. Zeinalzadeh
DELTA, Dortmund, Germany

Funding: Work supported by DFG, BMBF and by the Federal State NRW.
At the 1.5 GeV synchrotron light source DELTA, operated by the TU Dortmund University, a new facility for ultrashort pulses in the VUV and THz regime is currently under commissioning. Here, the interaction of an intense, ultrashort laser pulse, co-propagating with the electrons in an optical klystron, leads to coherent synchrotron radiation at harmonics of the incident laser wavelength. The aim of the present commissioning steps is to extend the emitted wavelength down to about 50 nm, enabling femtosecond-resolved pump-probe experiments in the VUV regime. Other issues include increasing the photon flux by optimizing the laser-electron interaction and improving the stability and ease of operation of the source.

TUPPP009

Status of the PETRA III Upgrade

undulator, shielding, vacuum, site

1620

M. Bieler, K. Balewski, W. Drube, J. Keil, A. Kling
DESY, Hamburg, Germany

Since 2010 PETRA III, a third generation light source at DESY, has been running as a user facility, with all 14 undulator beam lines operational since autumn 2011. In order to fulfill the request for more beam time after the shut down of DORIS at the end of 2012, it was decided to add two additional halls at PETRA III, each housing 5 additional beam lines. Next to these two new halls about 100 m of the accelerator will be completely remodeled to install additional undulators. The upgrade should be accomplished during a 6 month shut down in 2013. In order to minimize this down time, it was decided to keep the existing accelerator tunnel in place. This has impact both on the mechanical connection between the accelerator and the experimental floor and on the design of the optical beam lines in the tunnel. In this paper the layout of the upgraded accelerator will be shown. The design status of the major components for the upgrade will be presented.

TUPPP010

Spectral and Temporal Observations of CSR at ANKA

synchrotron, storage-ring, optics, synchrotron-radiation

1623

V. Judin, N. Hiller, A. Hofmann, E. Huttel, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M. Schuh, M. Schwarz, N.J. Smale, M. Streichert
KIT, Karlsruhe, Germany
M.J. Nasse
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320.
ANKA is a synchrotron light source situated at the Karlsruhe Institute of Technology. Using dedicated low-α-optics at ANKA we can reduce the bunch length and generate Coherent Synchrotron Radiation (CSR). Studies of the coherent emission in the time domain allow us to gain an insight into the longitudinal bunch dynamics. These as well as the systematic investigations of the THz spectrum range can be used for benchmarking of theoretical predictions. In this paper we report about the recent progress in CSR observation using fast THz detectors and a Martin-Puplett spectrometer at the ANKA storage ring.

TUPPP036

Large-scale Simulation of Synchrotron Radiation using a Lienard-Wiechert Approach

simulation, electron, synchrotron, synchrotron-radiation

1689

R.D. Ryne, C.E. Mitchell, J. Qiang
LBNL, Berkeley, California, USA
B.E. Carlsten, N.A. Yampolsky
LANL, Los Alamos, New Mexico, USA

Funding: DOE Office of Science, Office of Basic Energy Sciences; NNSA.
Synchrotron radiation is one of the most important and difficult to model phenomena affecting lepton accelerators. Large-scale parallel modeling provides a means to explore properties of synchrotron radiation that would be impossible to study through analytical methods alone. We have performed first-principles simulations of synchrotron radiation, using a Lienard-Wiechert approach, with the same number of simulation particles as would be found in bunches with charge up to 1 nC. The results shed light on the importance of shot noise effects, the amplification of coherent synchrotron radiation due to longitudinal microbunching, the interplay of electric and magnetic forces, and the limits of the widely used one-dimensional model.

TUPPP039

Vertical Dispersion Bump Design for Femto-second Slicing Beamline at the ALS

coupling, lattice, quadrupole, emittance

1698

C. Sun, C. Steier, W. Wan
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Femto-second (fs) slicing beamline has been brought to the operation at the Advanced Light Source (ALS) since 2002. It employs the resonant interaction of an electron bunch with a fs laser beam in a wiggler to energy-modulate a short section of the bunch. The induced energy modulation is then converted to a transverse displacement using a vertical dispersion bump downstream of the wiggler. Thus, the radiation from the fs pulse can be separated from the main bunch radiation. The current dispersion bump design has proved to be an effective and reliable one. However, the ALS storage ring lattice is under an upgrade to improve its brightness. After the completion of the upgrade, a new low emittance will be implemented, and the current dispersion bump design needs to be modified to provide the adequate vertical displacement, while minimizing the vertical emittance and spurious dispersion. In this paper, we present the new design of a vertical dispersion bump using Multi-Objective Genetic Algorithm (MOGA) for the ALS upgrade lattice.

TUPPP056

Study of the Energy Chirp Effects on Seeded FEL Schemes at SDUV-FEL

FEL, electron, laser, undulator

1724

C. Feng, D. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Seeded free-electron laser (FEL) schemes hold great promise for generation of high brilliant radiation with a narrow bandwidth. Analysis with the idealized electron beam with constant current and energy indicate that both the high-gain harmonic generation (HGHG) and the echo-enabled harmonic generation (EEHG) can produce Fourier-transform limited radiation pulses. However, residual energy variations due to nonlinearity of the accelerator or energy modulations due to microbunching instability will be unavoidable and may broaden the bandwidth of the seeded FEL. In this paper, we study the energy chirp effects on both the HGHG and EEHG schemes. Analytic and simulation calculations are presented and compared with the experimental data. Results show that the coherence properties of the EEHG FEL may not be degraded by the energy chirp when properly choosing the parameters of the dispersion sections.

TUPPP057

Design of a Wavelength Continuously Tunable Ultraviolet Coherent Light Source

FEL, laser, simulation, undulator

1727

T. Zhang, D. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
X.M. Yang
DICP, Dalian, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (Grant No. 11075199)
Dalian Coherent Light Source (DCL) is a proposed FEL-based novel light source user facility, will be located in Dalian city, China. DCL will mainly servers on the field of molecular reaction dynamics, ultra-fast physical chemistry experiments, etc. Running on the High-Gain-Harmonic-Generation (HGHG) FEL mode, DCL is expected to cover the FEL wavelength from 50 nm to 150 nm, with the help of continuously tuning Optical Parametric Amplification (OPA) seed laser system, which wavelength can be varied between 240 nm and 360 nm. Numerical simulation shows that the FEL pulse energy of DCL can surpass 100 μJ, at the whole full range wavelength with the undulator tapering technology, and the photon number can be up to 10¹³ per pulse, which is sufficient for user experiments.

TUPPP059

Effects of Metal Mirrors Reflectivity and Aberrations on THz FEL Radiation Performance

FEL, cavity, undulator, electron

1729

P. Tan, T. Yu
HUST, Wuhan, People's Republic of China
M. Fan, Q. Fu, D. Li, B. Qin, Y.Q. Xiong, Y.B. Yibin
Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China

The primary design study of terahertz free-electron laser (FEL) is presented in this paper. The effects of optical cavity parameter, metal mirrors reflectivity and aberrations on the THz FEL radiation performance have been explored. The reflectivity characteristics of copper, silver and gold are tested in terahertz region. The effects of metal mirrors reflectivity and aberrations on the THz FEL radiation performance are studied by numerical simulation.

TUPPP076

Soft Orbit Bumps for Duke Storage Ring VUV FEL Operation

FEL, wiggler, electron, dipole

1774

S.F. Mikhailov, J.Y. Li, V. Popov, P.W. Wallace, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DoE grant # DE-FG02-97ER41033.
The Duke FEL and High Intensity Gamma-ray Source (HIGS) facility is operated with an electron beam from 0.24 to 1.2 GeV and a photon beam from 190 to 1060 nm. The current range of the gamma-beam energy is from 1 MeV to about 100 MeV, with the maximum total gamma-flux of more then 10¹⁰ gammas per second around 10 MeV. Production of the high intensity, high energy gamma-beams of 60-100 MeV using UV-VUV mirrors of 240 - 190 nm requires and high energy, high current electron beams of 0.9-1.05 GeV. The radiation damage problem becomes more severe for VUV FEL operation below 190 nm. The radiation from the End-of-Arc (EOA) bending magnets, instead of the radiation from FEL wigglers, is the dominant cause of a rapid degradation of the downstream FEL mirror. In this work, we propose a number of measures to significantly reduce the radiation from these dipole magnets as well as other potential sources of synchrotron radiation toward the FEL mirror. In particular, we describe the development of an orbit bump using designated "soft" orbit correctors. The magnetic field of these correctors is limited to produce a radiation with a critical wavelength close or below the FEL wavelength.

TUPPP082

Optimization of a Terawatt Free Electron Laser

undulator, FEL, electron, focusing

1780

J. Wu, X. Huang, Y. Jiao, A.U. Mandlekar, T.O. Raubenheimer, S. Spampinati, G. Yu
SLAC, Menlo Park, California, USA
P. Chu
FRIB, East Lansing, Michigan, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
There is great interest in generating a terawatt (TW) hard X-ray free electron laser (FEL) that will enable coherent diffraction imaging of complex molecules like proteins and probe fundamental high-field physics. A feasibility study of producing such pulses was carried out em- ploying a configuration beginning with an SASE amplifier, followed by a "self-seeding" crystal monochromator, and finishing with a long tapered undulator. The undulator tapering profile, the phase advance in the undulator break sections, the quadrupole focusing strength, etc. are parameters to be optimized. A genetic algorithm (GA) is adopted for this multi-dimensional optimization. Concrete examples are given for LCLS/LCLS-II systems.

TUPPP083

Multi-Dimensional Optimization of a Tapered Free Electron Laser

undulator, FEL, electron, focusing

1783

Y. Jiao, J. Wu
SLAC, Menlo Park, California, USA
Q. Qin
IHEP, Beijing, People's Republic of China

Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. In this paper, we report a multi-dimensional optimizer to maximize the radiation power in a tapered FEL by searching for an optimal taper profile as well as a reasonable variation in electron beam radius. Applications of the proposed multi-dimensional optimization to the terawatt-level, tapered FELs with LCLS-like electron beam parameters are presented, and the proposed optimization scheme is compared with the GINGER’s self-design taper algorithm. At the end, the dependence of the available maximum radiation power on various parameters of the initial electron beam, the initial radiation field and the undulator system is summarized.

TUPPP084

Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius

electron, undulator, FEL, simulation

1786

Y. Jiao, J. Wu
SLAC, Menlo Park, California, USA
Q. Qin
IHEP, Beijing, People's Republic of China

Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. An in-depth understanding of the tapering-related physics is required to explore the full potential of a tapered FEL, not only by tapering the undulator parameters in longitudinal dimension, but also optimizing the transverse effects. Based on the modified 1D FEL model and time-steady numerical simulations, we study the contribution of the variation in electron beam radius and the related transverse effects. Taking a terawatt-level, 120-m tapered FEL as example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.

TUPPP090

Studies of Controlled Laser-induced Microbunching Instability at Source Development Laboratory

laser, electron, linac, space-charge

1798

S. Seletskiy, B. Podobedov, Y. Shen, X. Yang
BNL, Upton, Long Island, New York, USA

We present the studies of controlled microbunching intentionally induced on the beam by the photocathode laser with modulated longitudinal profile. Varying the depth and frequency of longitudinal modulation of the laser pulse allowed us to observe the development of microbunching instability at BNL Source Development Laboratory (SDL) in the controlled environment. That allowed us to benchmark the model of the microbunching gain for the first time. In addition to that, we demonstrated for the first time a constructive work of a so-called longitudinal space charge amplifier, which in case under consideration can be utilized for enhancement of linac-based sources of THz radiation.

TUPPR004

ILC Conventional Facility in Asian Sites

site, linac, HLRF, cryogenics

1816

A. Enomoto, M. Miyahara
KEK, Ibaraki, Japan

The international linear collider (ILC) is on a stage of preparing technical design report (TDR). Through value engineering to reduce civil construction costs, the tunnel configuration was changed from double- tunnel scheme to single. The double-tunnel schme accomodates superconducting accelerator modules and their power supplies indipendently. This is a very natural scheme for setting an accelerator and its power supply nearby and for preventing radiation damage of the power supply. However, the single-tunnel scheme was proposed to reduce cost, and to avoid such radiation problem three kinds of high-level (HLRF) RF systems are proposed. We report the comparison of ILC main linac costs and construction schedules between eight cases for combinations of diferent tunnel excavation methods and HLRF systems; then, we report the potential facility design for the Asian sites.

TUPPR007

Beam Background and MDI Design for SuperKEKB/Belle-II

background, luminosity, scattering, neutron

1825

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

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

TUPPR020

Updates to the CLIC Post-collision Line

simulation, scattering, shielding, background

1855

L.C. Deacon
CERN, Geneva, Switzerland

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

TUPPR023

Final-Focus Optics for the LHeC Electron Beam Line

synchrotron, quadrupole, synchrotron-radiation, electron

1861

J.L. Abelleira
EPFL, Lausanne, Switzerland
J.L. Abelleira, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
H. Garcia
UPC, Barcelona, Spain

Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579.
One of the options considered for the ECFA-CERN-NuPECC design study for a Large Hadron electron Collider (LHeC)* based on the LHC is adding a recirculating energy-recovery linac tangential to the LHC. First designs of the electron Final Focus System have shown the need to correct the chromatic aberrations. Two designs using different approaches for the chromaticity correction are compared, namely, the local chromaticity correction** and the traditional approach using dedicated sections.
*LHeC Study Group, “A Large Hadron Electron Collider at CERN,” LHeC-Note 2011-001 (2011).
**J. Abelleria et al., "Design Status of LHeC Linac‐Ring Interaction Region," IPAC2011, p. 2796 (2011).

TUPPR045

Multi-cell VEP Results: High Voltage, High Q, and Localized Temperature Analysis

cavity, SRF, controls, monitoring

1918

F. Furuta, B. Elmore
Cornell University, Ithaca, New York, USA
A.C. Crawford
Fermilab, Batavia, USA
G.M. Ge, G.H. Hoffstaetter, M. Liepe
CLASSE, Ithaca, New York, USA

We are developing Vertical Electro Polishing (VEP) system for niobium superconducting RF cavity at Cornell University. VEP has been successfully applied on different cell shapes (TESLA and Re-entrant), and single and multi-cell cavities. VEP achieved high gradient of 39MV/m with TESLA shape single cell and of 36MV/m with TESLA shape 9-cell, respectively. Preliminary results of R&D on VEPed cavities show removal dependence on cavity performance. Temperature oscillation asymmetry was also found during the VEP process. We will report these recent results and further R&D plan of Cornell VEP.

TUPPR053

Conceptual Design of the Linac4 Main Dump

linac, simulation, proton, booster

1939

I.V. Leitao, C. Maglioni, A. Sarrió Martínez
CERN, Geneva, Switzerland

Linac4 is the new CERN linear accelerator intended to replace the aging Linac2 as the injector to the Proton Synchrotron Booster (PSB) for increasing the luminosity of the Large Hadrons Collider (LHC). By delivering a 160MeV H⁻ beam, Linac4 will provide the necessary conditions to double the brightness and intensity of the beam extracted from the PSB. This paper describes the conceptual design of the Linac4 Main Dump, where two different concepts relying respectively on water and air cooling were compared and evaluated. Based on the application of analytical models for the energy deposited by the beam, heat conduction and cooling concepts, a parametric study was performed. This approach allowed the identification of the “optimal” configuration for these two conceptual geometries and their relative comparison. Besides giving the theoretical guidelines for the design of the new dump, this work also contributes to the development of analytical tools to allow a better understanding of the influence of the several design parameters in this type of low-energy beam intercepting devices.

TUPPR054

Internal H⁰/H⁻ Dump for the Proton Synchrotron Booster Injection at CERN

vacuum, booster, linac, injection

1942

M. Delonca, C. Maglioni, A.A. Patapenka, A. Sarrió Martínez
CERN, Geneva, Switzerland

In the frame of the LHC Injectors Upgrade Project at CERN (LIU), the new 160MeV H⁻ Linac4 will inject into the four existing PS Booster rings after the conversion of H⁻ into H⁺ in a stripping foil. Given a limited stripping efficiency and possible foil failures, a certain percentage of the beam is foreseen to remain partially (H⁰) or completely (H⁻) unstripped. An internal dump installed into the chicane magnet to stop these unstripped beams is therefore required. This paper presents the conceptual design of the internal dump, reviewing loading assumptions, design constraints, limitations and integration studies. Power evacuation through the thermal contact between the core and the external active cooling is addressed and, finally, results from the numerical thermo-mechanical analyses are reported.

TUPPR067

Electromagnetic Field of Charged Particle Bunch Moving in Wire Metamaterial

electromagnetic-fields

1975

V.V. Vorobev, A.V. Tyukhtin
Saint-Petersburg State University, Saint-Petersburg, Russia

Funding: Saint Petersburg State University
We consider the field of bunch flying through a "wire metamaterial". Analytical and computational investigations are carried out. In the case of motion perpendicularly to the wires it is shown that the radiation concentrates in a small vicinity of the determined lines behind the bunch and the Pointing vector is directed along the wires. This phenomenon can be useful for charged bunch examination. Some calculations show that the measurements of electrical field intensity and energy flow density allow determining the length of the bunch and its velocity. The case of bunch moving along the wires is also examined. It is shown that the radiation can be generated only for the wires possessing non-conducting coating. The radiation is directed at a sharp angle to the wires.

WEXB01

Recent Advances and New Techniques in Visualization of Ultra-short Relativistic Electron Bunches

electron, laser, FEL, RF-structure

2091

D. Xiang
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. DOE under Contract No. DE-AC02-76SF00515.
This talk will address advances in the measurement of ultra-short relativistic bunches at femtosecond frontier in high-energy x-ray free-electron lasers (FELs). In general, this presentation will discuss several recently proposed novel techniques (i.e. mapping z exactly to delta * and x **, optical oscilloscope ***, etc.) that are capable of breaking the femtosecond time barrier in measurements of ultrashort bunches. In particular, this presentation will report on the all-optical, time-resolved method to probe beam longitudinal phase space with femtosecond time scale and 10^-5 energy scale resolution ****. The simultaneous measurement of temporal profile and beam slice energy spread after the FEL interaction is also shown to reveal the time-dependent x-ray radiation profile *****.
* Z. Huang et al., PRSTAB 13, 092801.
** D. Xiang, Y. Ding, PRSTAB 13, 094001.
*** G. Andonian et al., PRSTAB 14, 072802.
**** D. Xiang et al., PRSTAB 14, 112801.
***** Y. Ding et al., FEL11.

Slides WEXB01 [6.873 MB]

WEXB02

Diagnostics for High Power Targets and Dumps

target, diagnostics, proton, vacuum

2096

E. Gschwendtner
CERN, Geneva, Switzerland

High power targets and dumps are generally used for neutrino, antiproton, neutron and secondary beam production, or in waste management using intense beams. In order to guarantee an optimized and safe use of these targets and dumps, reliable instrumentation is needed; the diagnostics in high power beams around targets and dumps is reviewed. The suite of beam diagnostic devices used in such extreme environments is discussed, including their role in commissioning and operation. The handling and maintenance of the instrumentation components in high radiation areas will be addressed.

Slides WEXB02 [13.010 MB]

WEOAA02

Inorganic Scintillators for Particle Beam Profile Diagnostics of Highly Brilliant and Highly Energetic Electron Beams

electron, diagnostics, simulation, monitoring

2119

G. Kube, C. Behrens, C. Gerth, B. Schmidt
DESY, Hamburg, Germany
W. Lauth
IKP, Mainz, Germany
M. Yan
Uni HH, Hamburg, Germany

Transverse beam profile diagnostics in electron linacs are widely based on optical transition radiation (OTR) as standard technique. The experience from modern linac based light sources shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. As consequence, for the new 4th generation light sources as the European X-FEL, new reliable tools for transverse beam profile measurements are required. Scintillating screens are widely used for particle beam diagnostics, especially in transverse profile measurements at hadron machines and low energy electron machines where the intensity of OTR is rather low. Their usage may serve as an alternative way to overcome limitations in OTR based beam diagnostics imposed by the influence of coherent emission. However, there is only little information about scintillator properties for applications with high energetic electrons. Therefore, test experiments have been performed at the Mainz Microtron (MAMI) in order to study the screen applicability. The status of these experiments will be presented and the results will be discussed in view of scintillator material properties and observation geometry.

Slides WEOAA02 [1.648 MB]

WEOBB01

Measurement of the Local Energy Spread of Electron Beam at SDUV-FEL

laser, electron, FEL, bunching

2143

C. Feng, J.H. Chen, H.X. Deng, T. Lan, B. Liu, D. Wang, X. Wang, M. Zhang, T. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

The slice energy spread of electron beam is a very important parameter for high gain free electron lasers (FELs) especially the seeded FELs. Because of its extremely small value, highly accurate measurement of the slice energy spread is rather challenging. In this paper, we propose a novel method to accurately measure the slice energy spread based on the coherent harmonic generation (CHG) scheme. This method has been demonstrated on the Shanghai deep ultraviolent FEL (SDUV-FEL), and the results show that the slice energy spread is about only 1.2keV at the exit of the 136MeV linac when the bunch compressor is off, and this value change to about 2.6keV when the bunch compressor is on.
* Chao Feng, et al, Phys. Rev. ST Accel. Beams 14, 090701 (2011)

Slides WEOBB01 [3.309 MB]

WEOBB03

Computation of the Wigner Distribution for Undulator Radiation

undulator, electron, synchrotron, brightness

2149

I.V. Bazarov, A.D. Gasbarro
CLASSE, Ithaca, New York, USA

In the effort to optimize brightness in synchrotron radiation sources, questions arise as to the most desirable electron beam parameters given a particular insertion device. With a detailed understanding of the distribution of emitted photons, the electron beam profile can be effectively matched. We have developed tools which, by way of the Wigner distribution, compute the phase space of photons radiated by an electron bunch. An explanation is provided of the workings of the code itself with mention of important algorithms that have been implemented. We demonstrate via numerical examples the Wigner distributions of the undulator radiation. In particular, it is shown that the phase space of light differs appreciably from the Gaussian distribution assumed in many analytical expressions and, therefore, the more thorough approaches should be used for computation of related quantities.

Slides WEOBB03 [2.555 MB]

WEIC02

Future Medical Accelerator

neutron, proton, target, controls

2152

K. Yasuoka
Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan

In the future radiation/particle therapy, the 3D-methods would be expanded into 4D- and 5D-methods to achieve precise biological dose focused on tumor cells and to spare normal cells as much as possible. No further technologies would be required to develop the next accelerator for radiation/particle therapy except for accelerator- and hospital- based BNCT. The BNCT needs a “medical neutron accelerator” to produce high intensity epithermal neutrons.

Slides WEIC02 [3.054 MB]

WEIC04

Functional Materials Development using Accelerator-based Light Sources: Current Capabilities and Future Prospects

FEL, controls, synchrotron, electron

2156

W.R. Flavell
UMAN, Manchester, United Kingdom

Funding: UK Engineering and Physical Sciences Research Council (EPSRC), UK Science and Technology Facilities Council (STFC)
The development of accelerator-based light sources has allowed access to photons of very high brightness and wide tunability. These properties of synchrotron radiation (SR) mean that it can be used to resolve questions that can be answered in no other way, enabling unique contributions to the development of functional materials. Increasingly, these benefits have become essential to material evaluation in manufacturing – ranging from intelligent catalysts for automotive emissions control* to next generation photovoltaics**. Bright, tunable X-rays have been a boon to nanotechnology*** in particular, with its requirement for atom-by-atom understanding – and this benefit is enhanced by the microfabrication capabilities of X-ray lithography in LIGA-based techniques. The result is unique potential for nanoscale device manufacture. The application of bright tunable X-rays to the development of nanostructures for a range of industrial applications is illustrated, and the prospects for exploitation of the ultra-high brightness and femtosecond time structure of FEL radiation are discussed.
* H Tanaka et al., Ang. Chemie Int. Ed. 45, 5998 (2006)
** S J O Hardman et al., Phys Chem Chem Phys 13, 20275 (2011)
*** S Biswas et al., Small (2012) DOI: 10.10⁰²/smll201102100

Slides WEIC04 [11.723 MB]

WEEPPB007

Initial Testing of the Mark-0 X-band RF Gun at SLAC

gun, solenoid, vacuum, cathode

2179

A.E. Vlieks, C. Adolphsen, V.A. Dolgashev, J.R. Lewandowski, C. Limborg-Deprey, S.P. Weathersby
SLAC, Menlo Park, California, USA

A new X band RF Gun (Mark-0) has been assembled, tuned and is being tested in the ASTA facility at SLAC. This gun has been improved from an earlier gun used in Compton-scattering experiments at SLAC by the introduction of a racetrack dual-input coupler to reduce quadrupole fields. Waveguide-to-coupler irises were also redesigned to reduce surface magnetic fields and therefore peak pulse surface heating. Tests of this photocathode gun will allow us to gain early operational experience for beam tests of a new gun with further improvements (Mark-1) being prepared for SLAC’s X-Band Test Accelerator (XTA) program and the LLNL MegaRay program. Results of current testing up to ≈ 200 MV/m peak surface Electric fields will be presented.

WEPPC011

Vertical Test Results for ERL 9-cell Cavities for Compact ERL Project

cavity, linac, cryomodule, HOM

2227

K. Umemori, T. Furuya, H. Sakai, M. Satoh, K. Shinoe
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan
M. Sawamura
JAEA, Ibaraki-ken, Japan

The Compact ERL project, which is a test facility of ERL, is ongoing in Japan. At the first step of this project, main linac cavities accelerate electron beams by 30 MV. Two 9-cell cavities were fabricated for main linac cryomodule, under High Pressure Gas Safety Code in Japan. A series of surface treatments, such as annealing, pre-tuning, electro-polishing (EP), degreasing, high pressure rinsing by ultra-pure water, cavity assembly and baking, were applied for the cavities. For the final EP, current density was selected to be relatively low. Vertical tests were performed for both cavities. Their field successfully reached to 25 MV/m, without any field limitation. The Q-values were more than 1x10¹⁰, even at 20 MV/m. Field emission on-sets were to be 14 and 22 MV/m, for each cavities. Both cavities satisfied requirements for ERL main linac cavity. Details of vertical tests, with X-ray and temperature mapping data, are shown, in this paper. These cavities will be mounted with titanium He jackets, assembled and installed into a cryomodule.

WEPPC014

Construction and Beam Operation of Capture Cryomodule for Quantum Beam Experiments at KEK-STF

cryomodule, cavity, controls, status

2236

Y. Yamamoto
KEK, Ibaraki, Japan

Construction of capture cryomodule for Quantum Beam Project has started since September, and will be finished by the end of December in 2011 at KEK-STF. Two MHI cavities (MHI-12, -13), which reached ILC specification (0.8x10¹⁰ at 35MV/m) at the vertical test, were installed into a short cryomodule with improved input couplers. Slide-Jack tuner was attached at different position (center or end of helium jacket) for each cavity same as S1-Global. From January 2012, this cryomodule will be cooled down to 2K, and the high power test will be started including check of the cavity/coupler/tuner performance, LFD measurement, LFD compensation by Piezo, dynamic loss measurement and so on. From March, the beam operation with the beam current of 10mA and the maximum beam energy of 40MeV, will be started to generate x-rays by collision between electron beam and laser. At this stage, two cavities will be operated at the lower gradient of 15-20MV/m, and the stable operation is crucial. In this report, the test results of various performances at the Quantum Beam Project will be presented in detail.

WEPPC050

Main Couplers for Project X

vacuum, cavity, linac, cryomodule

2324

S. Kazakov, M.S. Champion, S. Cheban, T.N. Khabiboulline, M. Kramp, Y. Orlov, V. Poloubotko, O. Pronitchev, V.P. Yakovlev
Fermilab, Batavia, USA

Design of 325MHz and 650MHz multi-kilowatt CW main couplers for superconducting linac of Project X is described. Results of electrodynamics, thermal and mechanical simulations is presented.

WEPPC070

Automated Cavity Test Suite for Cornell's ERL Program

cavity, controls, EPICS, linac

2372

D. Gonnella, M. Liepe, N.R.A. Valles
CLASSE, Ithaca, New York, USA

As of 2011, fabrication and testing of main linac 7-cell cavities has begun for Cornell's Energy Recovery Linac prototype project. To standardize the testing process, minimize errors and allow for quick and precise measurements of these cavities, a suite of MatLab programs has been written to automate cavity tests. The programs allow measuring the quality factor versus temperature, and quality factor vs. accelerating gradient, and allow extracting material properties such as RRR and residual resistance. They are compatible with EPICS input/output controllers or standalone computers. Finally, the program can measure continuous Q vs E curves from a single high field decay curve, and can perform temperature mapping and quench localization from oscillating superleak transducer data.

WEPPC088

Standardization of CEBAF 12 GeV Upgrade Cavity Testing

cavity, HOM, survey, LabView

2420

T. Bass, G.K. Davis, C. Grenoble, M. Stirbet
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
CEBAF 12GeV upgrade project includes 80 new 7-cell cavities to form 10 cryomodules. Each cavity underwent RF qualification at 2 Kelvin using a high power accelerating gradient test and an HOM survey in JLab’s Vertical Testing Area (VTA) before cavity string assembly. In order to ensure consistently high quality data, updated cavity testing procedures and analysis were implemented and used by a group of 10 VTA operators. For high power tests, a cavity testing procedure was developed and used in conjunction with a LabVIEW program to collect the test data. Additionally while the cavity was at 2K, an HOM survey was performed using a network analyzer and a combination of Excel and Mathematica programs. Data analysis was standardized and an online logbook, Pansophy, was used for data storage and mining. The Pansophy system allowed test results to be easily summarized and searchable across all cavity tests. In this presentation, the CEBAF 12GeV upgrade cavity testing procedure, method for data analysis, and results reporting results will be discussed.

WEPPC089

SRF Cavity Performance Overview for the 12 GeV Upgrade

cavity, cryomodule, SRF, HOM

2423

A. Burrill, G.K. Davis, C.E. Reece, A.V. Reilly, M. Stirbet
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The CEBAF accelerator, a recirculating CW electron accelerator that is currently operating at Jefferson Laboratory, is in the process of having 10 new cryomodules installed to allow for the maximum beam energy to be increased from 6 GeV to 12 GeV. This upgrade required the fabrication, processing and RF qualification of 80, seven cell elliptical SRF cavities, a process that was completed in February 2012. The RF performance achieve in the vertical testing dewars has exceeded the design specification by ~25% and is a testament to the cavity design and processing cycle that has been implemented. This paper will provide a summary of the cavity RF performance in the vertical tests, as well as review the overall cavity processing cycle and duration for the project.

WEPPC095

Evaluation of Silicon Diodes as In-situ Cryogenic Field Emission Detectors for SRF Cavity Development

cavity, ion, SRF, cryogenics

2438

A.D. Palczewski, R.L. Geng
JLAB, Newport News, Virginia, USA

Funding: This work is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We performed in-situ cryogenic testing of five silicon diodes as possible candidates for field emission monitor of SRF cavities in vertical testing dewars and in cryo-modules. We evaluated diodes from 2 companies - from Hamamatsu corporation model S5821-02 (used at KEK)* and S1223-02; and from OSI Optoelectronics models OSD35-LR-A, XUV-50C, and FIL-UV20. The measurements were done by placing the diodes in superfluid liquid helium near a field emitting 9-cell cavity during its vertical test. For each diode, we will discuss their viability as a 2K cryogenic detector for FE mapping of SRF cavities and their directionality in such environments. We will also present calibration curves between the diodes and JLab’s standard radiation detector placed above the dewar top plate and within radiation shielding.
* H. Sakai et al., Proc of IPAC10, WEPEC028 p. 2950 (2010).

WEPPD007

Integrated Thermal Analysis of the FRIB Cryomodule Design

cryomodule, cryogenics, vacuum, simulation

2510

Y. Xu, M. Barrios, F. Casagrande, M.J. Johnson, M. Leitner
FRIB, East Lansing, Michigan, USA
D. Arenius, V. Ganni, W.J. Schneider, M. Wiseman
JLAB, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Thermal analysis of the FRIB cryomodule design is performed to determine the heat load to the cryogenic plant, to minimize the cryogenic plant load, to simulate thermal shield cool down as well as to determine the pressure relief sizes for failure conditions. Static and dynamic heat loads of the cryomodules are calculated and the optimal shield temperature is determined to minimize the cryogenic plant load. Integrated structural and thermal simulations of the 1100-O aluminium thermal shield are performed to determine the desired cool down rate to control the temperature profile on the thermal shield and to minimize thermal expansion displacements during the cool down. Pressure relief sizing calculations for the SRF helium containers, solenoids, helium distribution piping, and vacuum vessels are also described.
Michigan State University designs and establishes FRIB as a DOE Office of Science National User Facility in support of the mission of the Office of Nuclear Physics.

WEPPD019

Manufacturing and Welding Process of Straight Section of Aluminum Alloy UHV Chambers for Taiwan Photon Source

vacuum, photon, synchrotron, synchrotron-radiation

2537

C.-C. Chang, C.K. Chan, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu
NSRRC, Hsinchu, Taiwan

This paper describes the manufacturing process and welding sequence for the aluminum extrusion vacuum chamber for the straight sections in Taiwan Photon Source. The straight section composes of aluminum extrusion chamber of A6063 and BPM chamber of A6061 aluminum alloys. The straightness and flatness of these extrusion chambers are controlled under 0.1mm/m and 0.2mm/m, respectively. The BPM chambers are manufactured precisely in oil-free environment, which provide clean surface and a precise sealing surface after machining. All the components are assembled in pre-aligned support system through the welding process. The aluminum chamber for 24 straight sections has been welded. The results show the straightness of < 0.15mm/m, flatness of < 0.3mm/m, and leakage rates of < 2 × 10^-10 mbarl/sec. were achieved.

WEPPD025

LHC Detector Vacuum System Consolidation for Long Shutdown 1 (LS1) in 2013-2014

vacuum, ion, background, electron

2555

M.A. Gallilee, J. Chaure, P. Cruikshank, J.E. Gallagher, C. Garion, J.M. Jimenez, R. Kersevan, H. Kos, L. Leduc, P. Lepeule, N. Provot, H. Rambeau, R. Veness
CERN, Geneva, Switzerland

The LHC has ventured into unchartered territory for Particle Physics accelerators. A dedicated consolidation program is required between 2013 and 2014 to ensure optimal physics performance. The experiments, ALICE, ATLAS, CMS, and LHCb, will utilise this shutdown, along with the gained experience of three years of physics running, to make optimisations to the detectors. New vacuum technologies have been developed for the experimental areas, to be integrated during this first phase shutdown. These technologies include bellows, vacuum chambers and ion pumps in aluminium, new beryllium vacuum chambers, and composite mechanical supports. An overview of this first phase consolidation program for the LHC experiments is presented.

WEPPD030

Concept for the Antiproton Production Target at FAIR

target, antiproton, proton, synchrotron

2570

K. Knie, B. Franzke, V. Gostishchev, M. Steck
GSI, Darmstadt, Germany
P. Sievers
CERN, Geneva, Switzerland

We will report on the status of the antiproton production target for the FAIR facility. A Ni target will be bombarded by a pulsed beam of 29 GeV protons with an intensity of 2.5·10¹³ ppp and a repetition rate of 0.2 Hz. Directly after the target the antiprotons will be focussed by a magnetic horn. In the proceeding magnetic separator antiprotons with an energy of 3 GeV (± 3%) will be selected and transported to the antiproton collector ring. The planned setup of the target area, including radiation protection issues, will be presented,

WEPPD033

Design of 100 MeV Proton Beam Irradiation Facility for the PEFP 100 MeV Linac

proton, target, linac, octupole

2579

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

Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government.
The Proton Engineering Frontier Project (PEFP) will install a 100-MeV proton linear accelerator at Gyeong-ju site. Two target rooms ( TR 103, TR 23) will be prepared in the beam commissioning stage for 20-MeV and 100-MeV proton beams, respectively. To design the irradiation equipment in TR 103, we have investigated general propagation shape and spatial distribution of proton beam by using Monte carlo method, when 100 MeV proton beam extracted from vacuum in the beam lines through beam window. On the basis of this result, we have designed beam irradiation components and their configuration. The beam irradiation facility consists of beam dump, support frame, sample support and beam current monitor. To minimize residual radioactivity induced by incident proton beam, the graphite was selected as the material of beam dump and the aluminum alloy was selected as material of other irradiation equipment. These residual radioactivity of equipment were estimated by Monte carlo method. In this paper, the details of this irradiation equipment design are presented.

WEPPD034

Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

cryomodule, electron, neutron, status

2582

C.M. Baffes, M.D. Church, J.R. Leibfritz, S.A. Oplt, I.L. Rakhno
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility’s initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type RF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a Helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. In addition, the potential for radiation-induced degradation of the graphite is discussed.

WEPPD035

Design Considerations for an MEBT Chopper Absorber of 2.1MeV H⁻ at the Project X Injector Experiment at Fermilab

vacuum, ion, cryomodule, neutron

2585

C.M. Baffes, M.H. Awida, A.Z. Chen, Y.I. Eidelman, V.A. Lebedev, L.R. Prost, A.V. Shemyakin, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
The Project X Injector Experiment (PXIE) will be a prototype of the Project X front end that will be used to validate the design concept and decrease technical risks. One of the most challenging components of PXIE is the wide-band chopping system of the Medium Energy Beam Transport (MEBT) section, which will form an arbitrary bunch pattern from the initially CW 162.5 MHz 5mA beam. The present scenario assumes diverting 80% of the beam to an absorber to provide a beam with the average current of 1mA to SRF linac. This absorber must withstand a high level of energy deposition and high ion fluence, while being positioned in proximity of the superconductive cavities. This paper discusses design considerations for the absorber, including specific challenges as spreading of energy deposition, management of temperatures and temperature-induced mechanical stresses, radiation effects, surface effects (sputtering and blistering), and maintaining vacuum quality. Thermal and mechanical analyses of a conceptual design are presented, and future plans for the fabrication and testing of a prototype are described.

WEPPD036

Energy Flow and Deposition in a 4-MW Muon Collider Target System

target, shielding, collider, factory

2588

N. Souchlas, R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA
X.P. Ding
UCLA, Los Angeles, California, USA
V.B. Graves
ORNL, Oak Ridge, Tennessee, USA
H.G. Kirk, H. K. Sayed
BNL, Upton, Long Island, New York, USA
K.T. McDonald
PU, Princeton, New Jersey, USA

Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886
The design of the target station for a 4-MW Muon Collider or a Neutrino Factory is evolving to include more space for services to the magnets and internal tungsten shielding, as well as consideration of removing the 5-T resistive copper coils, thereby reducing the peak field from 20 to 15 T. Simulations with MARS15 have been performed to verify that these revisions preserve sufficient shielding that the peak power deposition everywhere in the superconducting magnets will be less than 0.1 mW/g, permitting at least a 10-year operational lifetime against radiation damage to the organic insulators.

WEPPD040

Power Saving Schemes in the NSRRC

controls, synchrotron, synchrotron-radiation, status

2600

J.-C. Chang, Y.F. Chiu, Y.-C. Chung, Y.-C. Lin, C.Y. Liu, Z.-D. Tsai, T.-S. Ueng
NSRRC, Hsinchu, Taiwan

To cope with increasing power consumption and huge power bill of the Taiwan Photon Source (TPS) in the near future, we have been conducting several power saving schemes in the National Synchrotron Radiation Research Center (NSRRC) for years. This paper illustrates the power saving results and future schemes. The power saving schemes include optimization of chillers operation, power requirement control, air conditioning system improvement, application of heat pump, and the lighting system improvement.

WEPPD061

Quality Control of Modern Linear Accelerator: Dose Stability Long and Short-term

controls, factory, photon, monitoring

2660

T.U. Uddin
NICRH, Dhaka, Bangladesh

Quality Control (QC) data of modern linear accelerators, collected by National Institute of Cancer Research and Hospital, Dhaka, Bangladesh between the years 2006 and 2010, were analyzed. The goal was to provide information for the evaluation and elaboration of QC of accelerator outputs and to propose a method for QC data analysis. Short- and long-term drifts in outputs were quantified by fitting empirical mathematical models to the QA measurements. Normally, long-term drifts were well (≤1.5%) modeled by either a straight line or a single-exponential function. A drift of 2% occurred in 18 ± 12 months. The shortest drift times of only 2–3 months were observed for some new accelerators just after the commissioning but they stabilized during the first 2–3 years. The short-term reproducibility and the long-term stability of local constancy checks, carried out with a sealed plane parallel ion chamber, were also estimated by fitting empirical models to the QC measurements. The reproducibility was 0.3–0.6% depending on the positioning practice of a device. Long-term instabilities of about 0.3%/month were observed for some checking devices.

WEPPP012

High-Gradient THz-Scale Two-Channel Coaxial Dielectric-Lined Wakefield Accelerator

wakefield, acceleration, vacuum, focusing

2747

S.V. Shchelkunov, M.A. LaPointe
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
J.L. Hirshfield, T.C. Marshall
Omega-P, Inc., New Haven, USA
G.V. Sotnikov
NSC/KIPT, Kharkov, Ukraine

Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics.
A mm-scale THz Coaxial Dielectric Wakefield Accelerator structure is currently under study by Yale University Beam Physics Lab and collaborators for its performance with annular drive bunches. With our recent successful experiments with the cm-scale GHz rectangular module at AWA/Argonne (USA) and planned activity there with yet another cm-scale GHz coaxial structure, the program of new research has two objectives. The first is to design a structure to produce acceleration gradients approaching 0.35 GeV/m per each nC of drive charge when excited by an annular-like bunch; has an attractive feature that the drive and accelerated bunches both have good focusing and stability properties; and also exhibits a large transformer ratio. The second goal is to build and test the structure at FACET/SLAC (USA). At FACET the structure can be excited only with the available pencil-like drive bunch, but the reciprocity principle allows one to observe some of the properties that would be seen if the excitation were to be by an annular drive bunch. This presentation shows our latest findings, discusses related issues, and discusses our plans for experiments.

WEPPP022

Analysis of a Rectangular Dielectric-lined Accelerating Structure with an Anisotropic Loading

wakefield, electron, acceleration, impedance

2769

I.L. Sheynman, S. Baturin
LETI, Saint-Petersburg, Russia
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA

Funding: Russian Fund of Basic Research Federal target program "Scientific and scientific and pedagogical personnel of innovative Russia" of the Ministry of Education and Science of Russia.
Analysis of Cherenkov radiation generated by high current relativistic electron bunch passing through a rectangular waveguide with anisotropic dielectric loading has been carried out. Some of the materials used for the waveguide loading of accelerating structures (sapphire) possess significant anisotropic properties. In turn, it can influence excitation parameters of the wakefields generated by an electron beam. Using orthogonal eigenmodes decomposition for the rectangular dielectric waveguide, the analytical expressions for the wakefields have been obtained. Numerical modeling of the longitudinal and transverse (deflecting) wakefields has been carried out as well. It is shown that the dielectric anisotropy causes frequency shift in comparison to the dielectric-lined waveguide with the isotropic dielectric loading.

WEPPP023

Radiation of a Bunch Intersecting a Boundary between Vacuum and Dielectric in a Circular Waveguide

vacuum, wakefield, acceleration, plasma

2772

T.Yu. Alekhina, A.V. Tyukhtin
Saint-Petersburg State University, Saint-Petersburg, Russia

Funding: Saint Petersburg State University
Analysis of a field of a particle bunch in a waveguide loaded with a dielectric is important for the wakefield acceleration technique and for other problems in accelerator physics. We investigate the field of the bunch crossing a boundary between two dielectrics in a circular waveguide. We take into account the finite length of the bunch and analyze both the field structure and the energy loss. Special attention is paid to two cases: the bunch flies from vacuum into dielectric and from dielectric into vacuum. In the first case, investigation of formation of stationary wakefield is of interest (this is important for the wakefield acceleration technique). In the second case, quasi monochromatic wave is generated in the vacuum region. This effect can be used for elaboration of a quasi-monochromatic radiation generator of new type. In both cases we also study dynamics of the energy loss of the bunch.
* T.Yu. Alekhina, A.V. Tyukhtin. Proc. of IPAC2011, San Sebastian, Spain, WEPZ012, p. 2793 (2011).

WEPPP024

Cherenkov Radiation from a Small Bunch Moving in a Cold Magnetized Plasma

plasma, wakefield, acceleration, electromagnetic-fields

2775

S.N. Galyamin, D.Y. Kapshtan, A.V. Tyukhtin
Saint-Petersburg State University, Saint-Petersburg, Russia

Funding: Saint Petersburg State University.
Investigation of the bunch radiation in plasma is important for the plasma wakefield acceleration (PWFA) technique and other applications in accelerator physics. We study the electromagnetic field of small relativistic bunch moving in a magnetized cold plasma along the magnetic field. The energy loss of the bunch was investigated earlier, however the structure of electromagnetic field was not analyzed. We perform analytical and numerical investigation of total field. Different equivalent representations for the field components are obtained. One of them allows separating quasistatic field and radiation one. Method of computation is developed as well. Some interesting physical effects are described. One of them is strong increase of some components of radiation field near the charge motion line (in the case of point charge). The case of a charged disc is considered as well. Prospects of use of obtained results for PWFA are discussed.

WEPPP042

Experimental Demonstration of Wakefield Effects in a 250 GHz Planar Diamond Accelerating Structure

wakefield, dipole, acceleration, electron

2816

S.P. Antipov, J.E. Butler, C.-J. Jing, A. Kanareykin, P. Schoessow, S.S. Zuo
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
W. Gai
ANL, Argonne, USA

Funding: DOE SBIR
We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism. Fields produced by a first, drive, beam were used to accelerate a second, witness, electron bunch which followed the driving bunch at an adjustable distance. The energy gain of the witness bunch as a function of its separation from the drive bunch is a direct measurement of the wake potential. We also present wakefield mapping results for THz quartz structures. In this case decelerating wake inside the bunch is inferred from the drive beam energy modulation.

WEPPP072

Beam Characterization and Coherent Optical Transition Radiation Studies at the Advanced Photon Source Linac

emittance, linac, diagnostics, laser

2876

J.C. Dooling, R.R. Lindberg, N. Sereno, C.-X. Wang
ANL, Argonne, USA
A.H. Lumpkin
Fermilab, Batavia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357.
The Advanced Photon Source facility includes a 450-MeV S-band linac with the option for injection from a photocathode (PC) rf gun. A diode-pumped, twice-frequency doubled Nd:glass regen laser (263 nm) is used with the Cu PC to generate the electron beams. Characterization of these beams and studies of the microbunching instability following beam compression in the four-dipole magnetic chicane are described. A suite of diagnostics is employed including a three-screen emittance section, a FIR coherent transition radiation autocorrelator, electron spectrometers, and an optical diagnostics end station. An energy chirp impressed on the beam is used to compress the 1-2 ps, rms bunch as it passes through the chicane. With compression, bunch lengths of 170-200 fs, rms at 450 pC are measured, and coherent optical transition radiation (COTR) due to the microbunching instability is observed. Mitigation techniques of the COTR in the beam profile diagnostics are demonstrated both spectrally and temporally. At 100 pC without compression normalized transverse emittances of 1.8 and 2.7 microns are observed in the x and y planes, in reasonable agreement with initial ASTRA simulations.

WEPPR018

Beam Experiments towards High-intensity Beams in RHIC

proton, injection, vacuum, cryogenics

2979

C. Montag, L. A. Ahrens, M. Blaskiewicz, J.M. Brennan, K.A. Drees, W. Fischer, T. Hayes, H. Huang, K. Mernick, G. Robert-Demolaize, K.S. Smith, R. Than, P. Thieberger, K. Yip, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Proton bunch intensities in RHIC will be increased from 2*10¹¹ to 3*10¹¹ protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results will be presented.

WEPPR054

Calculation of Coherent Wiggler Radiation using Eigenfunction Expansion Method

wiggler, impedance, damping, space-charge

3048

D. Zhou, Y.H. Chin, K. Ohmi
KEK, Ibaraki, Japan
G.V. Stupakov
SLAC, Menlo Park, California, USA

An analytic method originated by Y. H. Chin* was extended to calculate the electromagnetic fields and the longitudinal impedance due to coherent wiggler radiation (CWR) in a rectangular chamber. The method used dyadic Green functions based on eigenfunction expansion method in electromagnetic theory and was rigorous for the case of straight chamber. We re-derived the theory and did find the full expressions for the longitudinal impedance of a wiggler with finite length. With shielding of chamber, the CWR impedance indicated resonant properties which were not seen in the theory for CWR in free space.
* Y.H. Chin, LBL-29981, 1990.

WEPPR079

Observations of Microbunching Instabilities from a THz Port at Diamond Light Source

storage-ring, synchrotron, optics, electron

3114

W. Shields, G.E. Boorman, V. Karataev, A. Lyapin
JAI, Egham, Surrey, United Kingdom
R. Bartolini, A.F.D. Morgan, G. Rehm
Diamond, Oxfordshire, United Kingdom

Diamond Light source is a third generation synchrotron facility dedicated to producing radiation of outstanding brightness. Above a threshold current, the electron bunches are susceptible to the phenomenon known as the microbunching instability. This instability is characterised by the onset of radiation bursts, the wavelength of which is around one order of magnitude shorter than the bunch length. Near threshold, the bursting occurs quasi-‐periodically, however at higher currents, the bursting appears randomly. The high frequencies involved in these emissions make detection and analysis challenging. A port specifically for the investigation of mm wave emissions has recently been built at Diamond. Ultra fast Schottky Barrier Diode detectors have been installed to obtain data for only a small fraction of the bunch revolution time in an updated data acquisition system. The threshold current and subsequent evolution of the instability have been investigated.

WEPPR089

Experimental Progress: Current Filamentation Instability Study

plasma, simulation, emittance, electron

3141

B.A. Allen, P. Muggli
USC, Los Angeles, California, USA
M. Babzien, M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
C. Huang
LANL, Los Alamos, New Mexico, USA
J.L. Martins, L.O. Silva
IPFN, Lisbon, Portugal
W.B. Mori
UCLA, Los Angeles, California, USA

Funding: Work supported by: National Science Foundation and US Department of Energy.
Current Filamentation Instability, CFI, is of central importance for the propagation of relativistic electron beams in plasmas. CFI has potential relevance to astrophysics, magnetic field and radiation generation in the afterglow of gamma ray bursts, and inertial confinement fusion, energy transport in the fast-igniter concept. An experimental study of this instability is underway at the Accelerator Test Facility, ATF, at Brookhaven National Laboratory with the 60MeV electron beam and centimeter length capillary discharge plasma. The experimental program includes the systematic study and characterization of the instability as a function of beam (charge, transverse and longitudinal profile) and plasma (plasma density) parameters. Specifically, the transverse beam profile is measured directly at the plasma exit using optical transition radiation from a thin gold-coated silicon window. Experimental results show the reduction of the beam transverse size and the appearance of multiple (1-4) filaments and are a function of the plasma density. We will present simulation and experimental results, provide discussion of these results and outline next steps in the experiment.

THYB02

Influence of Electron Beam Parameters on Coherent Electron Cooling

electron, FEL, ion, acceleration

3213

G. Wang, Y. Hao
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
S.D. Webb
Tech-X, Boulder, Colorado, USA

Coherent electron cooling (CeC) is promising to revolutionize the cooling of high energy hadron beams. The intricate dynamics of the CeC depends both on the local density and energy distribution of the beam. This talk should present a rigorous analytical model of the 3D processes (including diffraction) in the modulator and the FEL and describe how the theory is applied to electron beams with inhomogeneous longitudinal density- and energy distributions in the process of CeC. The SPC would like you to describe the influence of electron beam energy and current variations along the bunch length.

Slides THYB02 [0.878 MB]

THPPC010

Beam Start-up of J-PARC Linac after the Tohoku Earthquake

linac, DTL, quadrupole, acceleration

3293

M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
T. Maruta, A. Miura, H. Sako, J. Tamura, G.H. Wei
JAEA/J-PARC, Tokai-mura, Japan

The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant recovering effort including the realignment of most linac components, we have resumed the beam operation of J-PARC linac in December 2011. In this paper, we present the experience in the beam start-up tuning after the earthquake and the status of the linac operation thereafter.

THPPC017

Study of Physical Processes of Acceleration of Electron Bunches with Extremal Density by Means of Stored Energy in Disk Loaded Waveguide Sections

electron, linac, acceleration, electromagnetic-fields

3314

S. Proskin, A. Kulago
MEPhI, Moscow, Russia

This presentation should consider a new theoretical method of SHF power increasing in DWLG sections. Within the presentation physical processes of the acceleration of extremely charge densities in the sections of a DWLG by the stored energy are described. As a result optimum travelling wave DWLG is taken and a simulation of acceleration processes of 20 ns electron beams is conducted.

THPPC035

Final Assembly and Testing of the MICE Superconducting Spectrometer Solenoids

solenoid, vacuum, instrumentation, focusing

3362

S.P. Virostek, M.A. Green, T.O. Niinikoski, H. Pan, S. Prestemon
LBNL, Berkeley, California, USA
R. Preece
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231.
The Muon Ionization Cooling Experiment (MICE) is an international effort to demonstrate the principle of ionization cooling in a segment of a realistic cooling channel using a muon beam. The experiment is sited at Rutherford Appleton Laboratory in England. A 4-tesla uniform field region at each end of the cooling channel will be provided by a pair of identical, 3-m long spectrometer solenoids. As the beam enters and exits the cooling channel, the emittance will be measured within both the upstream and downstream 400 mm diameter magnet bores. Each magnet consists of a three-coil spectrometer magnet group and a two-coil pair that matches the solenoid uniform field into the adjacent MICE cooling channel. An array of five two-stage cryocoolers and one single-stage cryocooler are used to maintain the temperature of the magnet cold mass, radiation shield and current leads. Previous testing revealed several operational and design issues related to heat leak and quench protection that have since been corrected. Details of the magnet design modifications and their final assembly as well as the results of quench training tests will be presented here.

THPPC036

The Alpha Ferrite-loaded Coaxial Resonator Cavity

cavity, damping, resonance, storage-ring

3365

A.N. Pham, S.-Y. Lee, T.H. Luo
IUCEEM, Bloomington, Indiana, USA

Funding: Grant N00164-08-GM03 P00004 from the NSWC Crane Division, DOE Grant DE-FG02-92ER40747, and NSF Grant PHY-0852368 (IU: 48-432-31).
The Advanced Electron Photon Facility (ALPHA)*,** is a joint collaboration between the Indiana University Center for Exploration of Energy and Matter and the Crane Naval Surface Warfare Center. The ALPHA storage ring will serve as a debuncher in single pass mode of operation. With a set of two gradient damping wigglers, the storage ring can also accumulate to achieve high charge density beams. In this report, we present the design, fabrication, and testing of the 15 MHz ferrite-loaded quarter-wave rf coaxial resonator cavity that will be utilized in the ALPHA storage ring. Topics pertaining to beam lifetime, radiation damping, ferrite-loaded transmission lines, and key cavity parameters will be discussed.
* S.Y. Lee, P.E. Sokol, et al, "The ALPHA Project at IU CEEM," Proceedings of the IPAC2010.
** S.Y. Lee, et al, "A low energy electron storage ring with tunable compaction factor," RSI 78, 2007.

THPPC053

First Experience at ELBE with the New 1.3 GHz CWRF Power System Equipped with 10 kW GHz Solid State Amplifiers (SSPA)

klystron, cavity, electron, linac

3407

H. Büttig, A. Arnold, A. Büchner, M. Justus, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig, G.S. Staats, J. Teichert
HZDR, Dresden, Germany

The superconducting CW- LINAC (1.3 GHz) of the radiation source ELBE is in permanent operation since May 2001/1/. During the winter shut-down 2011 - 1212 an upgrade program of ELBE was realized. One part of the program was to double the RF-power per cavity using two 10 kW Solid State Amplifiers in parallel per cavity. The poster gives an overview on the new RF-system and the experience gained within the first three months of operation.

THPPD011

Radiation Hard Magnets at the Paul Scherrer Institute

target, shielding, vacuum, neutron

3518

A.L. Gabard, J.P. Duppich, D. George
Paul Scherrer Institut, Villigen, Switzerland

Radiation hard magnets have been in operation at PSI for more than 30 years. Throughout this period, extensive experience was gained regarding both the conceptual design of these magnets and their operation. Worldwide, upcoming future projects for high intensity accelerators and spallation sources will create an increasing need for radiation hard magnets. Through a presentation of the PSI main accelerator facilities, this paper describes the lessons learned over the years regarding the operation of radiation hard magnets and explains a few basic design concepts adopted by PSI based on this experience.

THPPD024

Irradiation Effects in Superconducting Magnet Materials at Low Temperature

neutron, solenoid, superconducting-magnet, target

3551

M.Y. Yoshida, M.I. Iio, S. Mihara, T. Nakamoto, H. Nishiguchi, T. Ogitsu, M. Sugano, K. Yoshimura
KEK, Ibaraki, Japan
M. Aoki, T. Itahashi, Y. Kuno, A. Sato
Osaka University, Osaka, Japan
Y. Kuriyama, Y. Mori, B. Qin, K. Sato, Q. Xu, T. Yoshiie
Kyoto University, Research Reactor Institute, Osaka, Japan

Superconducting magnets for high intensity accelerators and particle sources are exposed to severe radiation from beam collisions and other beam losses. Neutron fluence on the superconducting magnets for the next generation projects of high energy particle physics, such as LHC upgrades and the COMET experiment at J-PARC, is expected to exceed 10²¹ n/m², which is close to the requirements on the fusion reactor magnets. Irradiation effects at low temperature in superconducting magnet materials should be reviewed to estimate the stability of the superconducting magnet system in operation and its life. The pion capture superconducting solenoids for the COMET experiment are designed with aluminum stabilized superconducting cable to reduce the nuclear heating by neutrons. Also, the heat is designed to be transferred in pure aluminum strips. Irradiation effects on the electrical conductance of aluminum stabilizer and other materials are tested at cryogenic temperature using the reactor neutrons. This paper describes the study on the irradiation effects for the magnet developments.

THPPD033

Using Permanent Magnets to Boost the Dipole Field for the High-energy LHC

permanent-magnet, dipole, cryogenics, background

3578

F. Zimmermann
CERN, Geneva, Switzerland
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan

Funding: Work supported by the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579.
The High-Energy LHC (HE-LHC) will be a new accelerator in the LHC tunnel based on novel dipole magnets, with a field up to 20 T, which are proposed to be realized by a hybrid-coil design, comprising blocks made from Nb-Ti, Nb3Sn and HTS, respectively. Without the HTS the field would be only 15 T. In this note we propose and study the possibility of replacing the inner HTS layer by (weaker) permanent magnets that might contribute a field of 1-2 T, so that the final field would reach 16-17 T. Advantages would be the lower price of permanent magnets compared with HTS magnets and their availability.

THPPD042

High Radiation Environment Nuclear Fragment Separator Dipole Magnet

dipole, quadrupole, magnet-design, target

3605

S.A. Kahn
Muons, Inc, Batavia, USA
R.C. Gupta
BNL, Upton, Long Island, New York, USA

Funding: Supported in part by STTR Grant 4746 · 11SC06273
Magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) would be subjected to extremely high radiation and heat loads. Critical elements of FRIB are the dipole magnets which select the desired isotopes. Since conventional NiTi and Nb3Sn superconductors must operate at ~4.5 K, the removal of the high heat load generated in these magnets with these superconductors would be difficult. The coils for these magnets must accommodate the large curvature from the 30° bend that the magnets subtend. High temperature superconductor (HTS) have been shown to be radiation resistant and can operate in the 20-50 K temperature range where heat removal is an order of magnitude more efficient than at 4.5 K. Furthermore these dipole magnets must be removable remotely for servicing because of the extremely high radiation environment. This paper will describe the magnetic and conceptual design of these magnets.

THPPD043

Radiation-tolerant Multipole Correction Coils for FRIB

quadrupole, octupole, sextupole, multipole

3608

S.A. Kahn
Muons, Inc, Batavia, USA
R.C. Gupta
BNL, Upton, Long Island, New York, USA

Multipole correction insert coils with significant field strength are required inside the large aperture superconducting quadrupole magnets in the fragment separator section of the Facility for Rare Isotope Beams (FRIB). Correction coils made with copper do not create the required field and conventional low temperature superconductors are not practical in the fragment separator magnets which will operate at 40-50 K. The correction coils should be made of HTS as the main quadrupole coils are. There is a significant advantage to using HTS in these coils as it can withstand the high radiation and heat load that will be present. This paper will describe an innovative design suitable for coils with the complex end geometry of cylindrical coils. We will look at the forces on the corrector coils from the mail quadrupole fields and anticipate possible coil distortions.

THPPD044

Fabrication and Testing of Curved Test Coil for FRIB Fragment Separator Dipole

dipole, FEL, quadrupole, proton

3611

S.A. Kahn
Muons, Inc, Batavia, USA
J. Escallier, R.C. Gupta, G. Jochen, Y. Shiroyanagi
BNL, Upton, Long Island, New York, USA

Funding: Supported in part by SBIR Grant 4746 · 11SC06273
A critical element of the fragment separator region of the Facility for Rare Isotope Beams (FRIB) is the 30° dipole bend magnet. Because this magnet will be subjected to extremely high radiation and heat loads, operation at 4.5 K would not be possible. High temperature superconductors which have been shown to be radiation resistant and can operated in the 30-50 K temperature range which is more effective for heat removal. An efficient design for this magnet would make use of coils that follow the curvature of the magnet. Winding curved coils with negative curvature are difficult as the coil tends to unwind during the process. As part of an R&D effort for this magnet we are winding a ¼ scale test coil for this magnet with YBCO conductor and are testing it at 77 K. This paper will discuss the winding process and the test results of this study.

THPPD063

Zero Voltage Switching of Two-switch Flyback-Forward Converter

synchrotron, synchrotron-radiation, power-supply, photon

3656

J.C. Huang, K.-B. Liu, Y.S. Wong
NSRRC, Hsinchu, Taiwan

The traditional pulse-width-modulated flyback converter power switch has serious electromagnetic interference (EMI) and lower conversion efficiencies problems due to the hard-switching operations. This paper produces a zero voltage switching of flyback-forward converter with an active-clamp circuit, the traditional pulse-width-modulated flyback converter with a active clamp circuit to achieve zero-voltage-switching (ZVS) at both main and auxiliary switches, the active-clamp circuit can reduce most of switching loss and voltage spikes across the switches and improve the overall efficiency of the converter. The theoretical analysis of soft switching flyback-forward converter with an active-clamp circuit is verified exactly by a prototype of 50W with 100V input voltage, 5V output voltage and 30kHz operated frequency.

THPPD084

Analysis of Beam Loss Induced Abort Kicker Instability

high-voltage, kicker, factory, electron

3713

W. Zhang, L. A. Ahrens, W. Fischer, H. Hahn, J.-L. Mi, C. Pai, J. Sandberg, Y. Tan
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.

THPPP006

Radiation Damage to Electronics at the LHC

shielding, hadron, proton, luminosity

3734

M. Brugger
CERN, Geneva, Switzerland

Control systems installed in LHC underground areas using COTS (Commercial Off The Shelf) components are all affected by the risk of ‘Single Event Effects.’ In the LHC tunnel, in addition, cumulative dose effects have also to be considered. While for the tunnel equipment certain radiation tolerant design criteria were already taken into account during the LHC construction phase, most of the equipment placed in adjacent and partly shielded areas was not conceived nor tested for their current radiation environment. Given the large amount of electronics being installed in these areas, a CERN wide project called R2E (Radiation To Electronics) has been initiated to quantify the risk of radiation-induced failures and to mitigate the risk for nominal beams and beyond to below one failure a week. This paper summarizes the analysis and mitigation approach chosen for the LHC, presents the encountered difficulties and the obtained experience in the following aspects: radiation fields & related calculations, monitoring and benchmarking; commercial equipment/systems and their use in the LHC radiation fields; radiation tests with dedicated test areas and facilities*.
* Work presented on behalf of the CERN ’Radiation to Electronics (R2E) Mitigation Project’ and the ‘Radiation Working Group (RadWG)’

THPPP018

Operation of the LHC at High Luminosity and High Stored Energy

luminosity, injection, vacuum, emittance

3767

J. Wenninger, R. Alemany-Fernandez, G. Arduini, R.W. Assmann, B.J. Holzer, E.B. Holzer, V. Kain, M. Lamont, A. Macpherson, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli Camillocci, J.A. Uythoven, W. Venturini Delsolaro
CERN, Geneva, Switzerland

In 2011 the operation of the Large Hadron Collider LHC entered its first year of high luminosity production at a beam energy of 3.5 TeV. In the first months of 2011 the number of bunches was progressively increased to 1380, followed by a reduction of the transverse emittance, an increase of the bunch population and a reduction of the betatron function at the collision points. The performance improvements steps that were accumulated in 2011 eventually brought the peak luminosity to 3.6·10³³ cm^-2s⁻¹. The integrated luminosity delivered to each of the high luminosity experiments amounted to 5.6 fb-1, a factor of 5 above the initial target defined in 2010. The operational experience with high intensity and high luminosity at the LHC will be presented here, together with the issues that had to be tackled on the road to high intensity and luminosity.

THPPP067

H⁻ Beam Loss and Evidence for Intrabeam Stripping in the LANSCE Linac

linac, ion, electron, emittance

3892

L. Rybarcyk, C.T. Kelsey, R.C. McCrady, X. Pang
LANL, Los Alamos, New Mexico, USA

Funding: U.S. Dept. of Energy, NNSA, under contract DE-AC52-06NA25396.
The LANSCE accelerator complex is a multi-beam, multi-user facility that provides high-intensity H⁺ and H⁻ particle beams for a variety of user programs. At the heart of the facility is a room temperature linac that is comprised of 100-MeV drift tube and 800-MeV coupled cavity linac (CCL) structures. Although both beams are similar in intensity and emittance, the beam-loss monitors along the CCL show a trend of increased loss for H⁻ that is not present for H⁺. This difference is attributed to stripping mechanisms that affect H⁻ and not H⁺. We present the results of an analysis of H⁻ beam loss along the CCL that incorporates beam spill measurements, beam dynamics simulations, analytical models and radiation transport estimates using the MCNPX code. The results indicate a significant fraction of these additional losses result from intrabeam stripping.

THPPP084

Charge Stripping of Uranium-238 Ion Beam with Helium Gas Stripper

target, cyclotron, ion, acceleration

3930

H. Imao
RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
N. Fukunishi, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, H. Okuno, T. Watanabe, Y. Watanabe, Y. Yano, S. Yokouchi
RIKEN Nishina Center, Wako, Japan

Development of the reliable and efficient electric charge stripping method is one of the key issues in next-generation high-intensity heavy ion accelerators. Although conventional carbon-foil charge strippers provide a good charge stripping efficiency, two serious problems are emerging; the short usable time and thickness non-uniformity. A charge stripper using low-Z gas is an important candidate applicable for high-intensity 238U beams to replace carbon foil strippers. In the present work, the first actual charge stripping system using helium gas for 238U beams injected at 10.75 MeV/u has been developed and tested.

THPPR022

Radiation Dose Simulation and Measurement plan for SSRF Beam Lines by Using ATOM Phantoms

photon, neutron, simulation, synchrotron

4008

Y. Sheng, L.X. Liu, X. Xia, J.Q. Xu
SINAP, Shanghai, People's Republic of China

Radiation dose assessment in advanced synchrotron radiation facility is challenging due to the complexity and uncertainties of radiation source terms induced by high energy particle accelerator. Shanghai Synchrotron Radiation Facility, SSRF, is the first third-generation synchrotron facility in China, which was completed in 2009. Radiation dose assessment for workers at SSRF Beam lines is highly concerned. This study presents the dose simulation with Monte Carlo method. The dose simulation was performed with a hybrid phantom coupled into MCNPX code. The hybrid phantom was constructed by combining the ATOM phantom and the Voxel-based Chinese Reference female Phantom, VCRP-woman, originally developed by using the high resolution color photographs. The organs absorbed dose calculated for photon and neutron were compared. An Experiment of measuring the organs dose by using the ATOM phantom will be performed in the near future.

THPPR023

Radiation Shielding Design for Dream-Line Beamline at SSRF

shielding, synchrotron, synchrotron-radiation, target

4011

J.Q. Xu, L.X. Liu, J.J. Lv, Y. Sheng, X. Xia
SINAP, Shanghai, People's Republic of China

The dream-line beamline at Shanghai Synchrotron Radiation Facility, SSRF, is an under construction soft X-ray beam line with a wide energy range and super high energy resolution. It is required to allow online operation beside optical components in the experiment hutch at this beamline when synchrotron light is running. This requires more careful radiation shielding design for the beamline. The radiation shielding designs for the beamline are considered to shield gas bremsstrahlung and synchrotron. Ray tracing was carried out according to the beamline structure and optical components layout. The residual gas bremsstrahlung with optical components and the induced dose rate distribution were simulated with the Fluka code. The synchrotron radiation scattering at optical components was calculated with the STAC08 code. With the simulated results, the specifications of shielding collimators, safety shutters, and hutch wall are given for the beamline. The normalized dose rate results by gas bremsstrahlung are consisted with the measurements or calculations results in other facilities in the world very well.
* Corresponding author: xiaxiaobin@sinap.ac.cn

THPPR024

Upgrade of Radiation Monitoring System at SSRF for Top-up Operation

monitoring, controls, neutron, injection

4014

X. Xia, J. Chen, J.J. Lv, W. Shen, T. Wan, W.F. Wu, X.J. Xu, H. Zhao
SINAP, Shanghai, People's Republic of China

The radiation monitoring system (RMS) at Shanghai Synchrotron Radiation Facility, SSRF, is required to upgrade to have dose interlock functions for top-up operation as an important safety issue. This paper describes the basic requirements, design criteria, signal network, and functions of the upgraded radiation monitoring system. Both the prompt dose rate and the accumulative dose alarm were archived for the safety issue after the upgrade. The reliability and stability of the upgraded RMS are in testing for getting operation permission from authority for radiation safety issue.

THPPR033

Tests and Measurements with the Embedded Radiation-monitor-system Prototype for Dosimetry at the European XFEL

undulator, linac, electron, neutron

4041

F. Schmidt-Föhre, D. Nölle, R. Susen, K. Wittenburg
DESY, Hamburg, Germany

A new Embedded Radiation-Monitor-System is currently under development for use in the upcoming European XFEL, that is being built at a length of approx. 3.4 km between the campus of the Deutsches Elektronen-Synchrotron DESY at Hamburg and Schenefeld at Schleswig-Holstein. Most of the electronic systems cabinets for machine control, diagnostics and safety of the XFEL will be located inside the accelerator tunnel. To prevent significant radiation damage at electronic systems in certain sections of the XFEL, all electronic cabinets inside the tunnel will be sufficiently shielded according to pre-estimated radiation levels. In addition, accumulated dose inside these electronic cabinets and in undulator regions will be monitored for the impact of Gamma- and Neutron-radiation by a new radiation monitor system. Life cycle estimations for these electronics and the undulators will provide safety limits for correct function and in time part exchange due to radiation, before significant radiation damage occurs. A prototype of the Gamma radiation-monitor system section has been successfully designed and tested at the DESY Linac II. Prototype tests and according measurements will be presented.

THPPR037

Estimation of Thresholds for the Signals of the BLMs around the LHC Final Focus Triplet Magnets

proton, simulation, luminosity, beam-losses

4053

M. Sapinski, F. Cerutti, B. Dehning, A. Ferrari, A. Lechner, M. Mauri, A. Mereghetti
CERN, Geneva, Switzerland
C. Hoa
CEA-CENG, Grenoble, France

The Interaction Points of the Large Hadron Collider are the regions where the two circulating beams collide. Hence, the magnets the closest to any Interaction Point are exposed to an elevated radiation field due to the collision debris. In this study the signal in the Beam Loss Monitors due to the debris is estimated and compared with the measurements. In addition, the energy density in the coils and the signal in the Beam Loss Monitors at quench are estimated for various beam loss scenarios. It is shown that the Beam Loss Monitors, as presently installed on the outside of the vacuum vessel of the magnets, cannot disentangle the signals due to a localised halo loss from that of the constant signal due to the collision debris.

THPPR041

The Conceptual Design of the Shielding Layout and Beam Absorber at the PXIE

shielding, cryomodule, proton, rfq

4065

Y.I. Eidelman, J.S. Kerby, V.A. Lebedev, J.R. Leibfritz, A.F. Leveling, S. Nagaitsev, R.P. Stanek
Fermilab, Batavia, USA

The Project X Injector Experiment (PXIE) is a prototype of the Project X front end. A 30 MeV 50 kW H⁻ beam will be used to validate the design concept of the Project X. This paper discusses a design of the accelerator enclosure radiation shielding and the beam dump. Detailed energy deposition and activation simulation were performed with the MARS15 code. The simulation results guided the design of the installation enclosure.

THPPR043

Applications of X-band 950 keV and 3.95 MeV Linac X-ray Source for On-site Inspection

linac, focusing, coupling, shielding

4071

M. Uesaka, K. Demachi, K. Dobashi, T. Fujiwara, H.F. Jin, M. Jin, H. Zhu
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
Y. Hattori
Hitachi Engineering & Services Co.,Ltd., Japan
J. Kusano, N. Nakamura, M. Yamamoto
Accuthera Inc., Kawasaki, Kanagawa, Japan
I. Miura
Mitsubishi Chemical Corporation, Japan
E. Tanabe
AET, Kawasaki-City, Japan

Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of a 250 kW magnetron and a cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. We have also developed a portable X-band (9.3GHz) 3.95MeV linac for on-site bridge inspection. The system consists of a 62kg X-ray source part without 80kg target collimator, a 62kg RF power source and other utility box of 116kg. Designed X-ray dose rate is 2 Sv/min@1m with 200pps repetition rate and we have achieved 0.5 Sv/min@1m with 50pps repetition rate. Demonstration of the measurement of wall thinning of metal pipes with thick thermal shielding by 950keV linac and degradation of reinforced concrete sample by 3.95MeV is under way. Updated measurement results will be presented.

THPPR049

Study on Electron Microbeam Generation for MRT Based on Photo-cathode RF-Gun

gun, electron, cathode, laser

4086

Y. Yoshida, K. Sakaue, M. Washio
RISE, Tokyo, Japan

We have been developing an MRT (Microbeam Radiation Therapy) based on Cs-Te photo cathode RF-Gun at Waseda University. MRT is proposed to treat tumor by using array of several micro-meter parallel beams. In this therapy, irradiated normal tissue repairs itself, by contrast, even a non-irradiated tumor tissue dies. In the other words, the microbeam enhances the radiation sensitivity difference between normal and tumor issues. Therefore, MRT is considered one of the most useful tumor therapies in the future. We have generated electron microbeam by tungsten collimator slit and analyzed their dose distribution in air and in the PMMA phantom. We have used radiochromic film called GAFCHROMIC dosimetry film type HD-810 to measure them. We have compared these experimental results with Monte Carlo simulation of the dose distribution using the EGS5 code. In this conference, we would like to report the electron microbeam procedure, optimization of irradiation condition, evaluation of microbeam specifications and future prospects.

THPPR058

Pulse Radiolysis using Double-decker Femtosecond Electron Beam from a Photocathode RF Gun

electron, linac, laser, gun

4106

K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Pulse radiolysis, which utilizes an electron bunch and a probe light (laser), is a powerful tool that can be used for an observation of ultrafast radiation-induced phenomena. The time resolution in pulse radiolysis depends on the electron bunch length, the probe-light width, and the timing jitter between the electron bunch and the probe light. In order to reduce the jitter, double-decker accelerator, in which separated laser was injected on a photocathode RF gun for a generation of synchronized double electron beams, was applied to pulse radiolysis. One electron beam was used as a pump source of a material, e. g. water, and another as a probe light at 800 nm wavelength with Cherenkov radiation.

THPPR059

Progress of the Equivalent Velocity Spectroscopy Method for Femtosecond Pulse Radiolysis by Pulse Rotation and Pulse Compression

electron, laser, cathode, linac

4109

T. Kondoh, K. Kan, K. Norizawa, A. Ogata, S. Tagawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan
H. Kobayashi
KEK, Ibaraki, Japan

Femtosecond pulse radiolysis is developed for studies of electron beam induced ultra-fast reaction in matter. 98 fs electron pulse was generated by a photocathode RF gun LINAC with a magnetic bunch compressor. However for more fine time resolution, the Equivalent velocity spectroscopy (EVS) method is required to avoid degradation of time resolution caused by velocity difference between electron and analysing light in sample. In the EVS method, incident analysing light is oblique toward electron beam with an angle associated with refractive index of sample, and then, electron pulse is rotated toward the direction of travel to overlap with light pulse. In previous studies, pulse rotation had not been compatible with pulse compression. However, by oblique incident of light to the photocathode, pulse rotation was compatible with pulse compression, and the time resolution was improved by principle of the equivalent velocity spectroscopy.

THPPR068

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

photon, laser, electron, scattering

4133

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

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

THPPR069

Compact, Inexpensive X-Band Linacs as Radioactive Isotope Source Replacements

linac, simulation, electron, coupling

4136

S. Boucher, R.B. Agustsson, X.D. Ding, L. Faillace, P. Frigola, A.Y. Murokh, M. Ruelas, S. Storms
RadiaBeam, Santa Monica, USA

Funding: Work supported by DNDO Phase II SBIR HSHQDC-10-C-00148 and DOE Phase II SBIR DE-SC0000865.
Radioisotope sources are still commonly used in a variety of industrial and medical applications. The US National Research Council has identified as a priority the replacement of high-activity sources with alternative technologies, due to the risk of accidents and diversion by terrorists for use in radiological dispersal devices (“dirty bombs”). RadiaBeam Technologies is developing novel, compact, inexpensive linear accelerators for use in a variety of such applications as cost-effective replacements. The technology is based on the MicroLinac (originally developed at SLAC), an X-band linear accelerator powered by an inexpensive and commonly available magnetron. Prototypes are currently under construction. This paper will describe the design, engineering, fabrication and future testing of these linacs at RadiaBeam. Future development plans will also be discussed.

THPPR072

High Power of 10 MeV, 25 kW Electron LINAC for Irradiation Applications

electron, linac, vacuum, simulation

4142

Y.J. Pei, G. Feng, Y. Hong, K. Jin, S. Lu, L. Shang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Using the electron beam to sterilize medical products and cosmetics, and food preservation and so on, has become important and efficient manners recently in number and variety. This paper describes the design, construction, and commissioning of a high power electron LINAC which can provide beam energy of 10 MeV, beam power of 25 kW. The paper also gives beam dynamic simulation results where beam loading effect was taken into account, and running parameters.