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MO102 Status of the European XFEL Project cavity, linac, SRF, undulator 6
 
  • H. Weise
    DESY, Hamburg
 
 

The internationally organized European XFEL free-electron laser is under construction at the Deutsches Elektronen-Synchrotron (DESY). The project is the first large scale application of the TESLA technology developed over the last 15 years. Superconducting accelerating cavities will be used to accelerate the electron beam to an energy of up to 17.5 GeV. Recently an energy reduction by 20% to 14 GeV was discussed as a reasonable compromise between cost aspects and scientific potential of the facility. With realistic assumptions on lower beam emittance, the design photon beam parameters will be achieved. The talk will briefly summarize the overall XFEL design before presenting details about the status of the superconducting linac. The activities within the international collaboration will be described. Final prototyping, industrialization and commissioning new infrastructure are the actual challenges. Contracts for long lead items are placed.

 

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MO303 CLIC Feasibility Demonstration at CTF3 linac, acceleration, laser, collider 36
 
  • R.J.M.Y. Ruber
    Uppsala University, Uppsala
 
 

At CERN the feasibility of CLIC (Compact LInear Collider) a multi-TeV electron-positron collider is being studied. In this scheme the RF power to accelerate the main beam is produced by a high current drive beam. To demonstrate this scheme a test facility (CLIC Test Facility 3, CTF3) has been constructed at CERN. Recently, the complex to generate the drive beam has been successfully commissioned producing a beam with a current around 30A. This beam is now being used to test the power production. The results of the test facility provide vital input for the CLIC conceptual design report to be finished by the end of 2010. This talk describes CTF3 activities and their importance for CLIC; it comments on design readiness for CLIC after a successful CTF3 demonstration.

 

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MO304 3.9 GHz Cavity Module for Linear Bunch Compression at FLASH cavity, HOM, photon, simulation 41
 
  • H.T. Edwards, E.R. Harms
    Fermilab, Batavia
  • C. Behrens
    DESY, Hamburg
 
 

FNAL has contributed to FLASH at DESY the third harmonic accelerating system, which will provide better beams for the FEL facility. The FNAL accelerating module has been qualified above specs and will be operational in FLASH in Spring.

 

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MOP004 An Electron Linac Injector With a Hybrid Buncher Structure linac, gun, cathode, klystron 55
 
  • M. Hüning, M. Schmitz
    DESY, Hamburg
  • C. Liebig
    Uni HH, Hamburg
 
 

At present the Linac II at DESY consists of a 6A/150kV DC electron gun, a 400 MeV primary electron linac, a 800 MW positron converter, and a 450 MeV secondary electron/positron linac. To improve the maintainability of the system and to reduce operational risks the original 150kV diode gun will be replaced by a 100kV triode. Together with the gun the whole injection system will be upgraded and optimized for minimal load on the converter target and primary linac. The core of the new injector are a 5MeV standing wave/travelling wave hybrid structure and a magnetic energy filter. Simulations show that With 6A DC current up to 3.7A can be bunched into 20° of the 2.998 GHz RF. This phase range is narrow enough to fit after on-crest acceleration into the energy acceptance of the following accumulator ring PIA.

 
MOP005 LLNL's Precision Compton Scattering Light Source laser, gun, scattering, photon 58
 
  • F.V. Hartemann, F. Albert, S.G. Anderson, C.P.J. Barty, A.J. Bayramian, R.E. Bonnanno, T.S. Chu, R.R. Cross, C.A. Ebbers, D.J. Gibson, T.L. Houck, R.A. Marsh, D.P. McNabb, M. J. Messerly, R.D. Scarpetti, M. Shverdin, C. Siders, S.S.Q. Wu
    LLNL, Livermore, California
  • C. Adolphsen, A.E. Candel, E.N. Jongewaard, Z. Li, C. Limborg-Deprey, T.O. Raubenheimer, S.G. Tantawi, A.E. Vlieks, F. Wang, J.W. Wang, F. Zhou
    SLAC, Menlo Park, California
  • V.A. Semenov
    UCB, Berkeley, California
 
 

Continued progress in accelerator physics and laser technology have enabled the development of a new class of tunable x-ray and gamma-ray light sources based on Compton scattering between a high-brightness, relativistic electron beam and a high intensity laser pulse produced via chirped-pulse amplification (CPA). A precision, tunable, monochromatic (< 0.4% rms spectral width) source driven by a compact, high-gradient X-band linac designed in collaboration with SLAC is under construction at LLNL. High-brightness (250 pC, 3.5 ps, 0.4 mm.mrad), relativistic electron bunches will interact with a Joule-class, 10 ps, diode-pumped CPA laser pulse to generate tunable γ-rays in the 0.5-2.5 MeV photon energy range. This gamma-ray source will be used to excite nuclear resonance fluorescence in various isotopes. Fields of endeavor include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status will be discussed, along with important applications, including nuclear resonance fluorescence and high precision medical imaging.

 
MOP007 SLAC Linac Preparations for FACET linac, shielding, positron, injection 61
 
  • R.A. Erickson, L.D. Bentson, D. Kharakh, A.R. Owens, P. Schuh, J. Seeman, J. Sheppard, M. Stanek, U. Wienands, W. Wittmer, G. Yocky
    SLAC, Menlo Park, California
 
 

Submitted for the Sector 0-20 Core Team. The SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the proposed new experimental facility for accelerator science and test beams. In this paper, we describe this separation and several projects to prepare the linac for the FACET experimental program.

 
MOP008 Reducing the Energy Spread of Recirculating Linac by Non-isochronous Beam Dynamics recirculation, linac, quadrupole, cavity 64
 
  • R. Eichhorn, A. Araz, J. Conrad, F. Hug, M. Konrad, T. Quincey
    TU Darmstadt, Darmstadt
 
 

The Superconducting Linear Accelerator S-DALINAC at the University of Darmstadt (Germany) is a recirculating Linac with two recirculations. Currently acceleration in the Linac section is done on crest of the accelerating field. The recirculation path is operated achromatic and isochronous. In this recirculation scheme the energy spread of the resulting beam in the ideal case is determined by the electron bunch length. Taking into account the stability of the RF system the energy spread increases drastically. In this work we will present a new non-isochronous recirculation scheme which helps canceling out these errors from the rf-control. This scheme uses longitudinal dispersion in the recirculation pathes and an acceleration off-crest with a certain phase with respect to the maximum. We will present beam dynamic calculations which show the usability of this system even in a Linac with only two recirculations and first experimental results

 
MOP009 Generation of Low-energy Electron Beam Using KURRI-LINAC acceleration, gun, linac, bunching 67
 
  • T. Kubota, N. Abe, J. Hori, T. Takahashi
    KURRI, Osaka
 
 

Electron beam can be accelerated in two accelerator tubes up to 46 MeV at KURRI-LINAC. The development of irradiation field is planned to provide lower energy electron beam. For this purpose we had regulated several parameters, which results showed that low energy electron beam was obtained by acceleration in only the first accelerator tube, without the second one, which was filled with microwave from klystron operated at reduced voltage. Moreover, the timing between electron emission and microwave introduction into the first accelerator tube was varied to increase the electron energy loss in the second one, thereby reducing high-energy component of the beam. In this study we obtain lower energy electron beam by the following regulations: 1) the increase of the emission current from the electron gun relative to energy filled into the first accelerator tube results in the decrease of acceleration energy for each electron and 2) the total control of the timing and the buncher phase of microwave and the width of electron pulse eliminates a part of electron expected to be high-energy component. The regulations described above yield the low-energy electron beam with peak of 5.2 MeV.

 
MOP011 Injector Linac Upgrade for SuperKEKB positron, linac, emittance, injection 70
 
  • T. Kamitani, M. Akemoto, D.A. Arakawa, A. Enomoto, S. Fukuda, K. Furukawa, T. Higo, H. Honma, K. Hosoyama, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, H. Katagiri, M. Kikuchi, Y. Kojima, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, H. Nakajima, K. Nakanishi, K. Nakao, Y. Ogawa, S. Ohsawa, T. Sanami, M. Satoh, T. Shidara, A. Shirakawa, T. Sugimura, T. Suwada, T. Takenaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida
    KEK, Ibaraki
 
 

The KEKB-factory will be upgraded for 40 times higher lumnosity (SuperKEKB). The injector linac is required to increase the beam intensities (e-:1nC -> 5nC, e-:1nC -> 4nC) and reduce the emittances (e-:300 -> 20 um, e+: 2100 -> 10 um ) for the SuperKEKB. A photo-cathode RF gun will be introduced to generate the high-intensity and low-emittance electron beams. A positron damping ring will be constructed to reduce the emittance. A new matching device (a flux concentrator or a superconducing magnet) and an L-band capture section will be introduced to increase the positron intensity. Beam line layout down to the damping ring will be rearranged to have sufficient beam acceptance considering the positron emitttance. This paper describes details of the upgrade scheme of the injector linac.

 
MOP015 New Pump-Probe System Using the Coherent Radiation from a Linac Electron Beam at OPU radiation, linac, synchrotron, gun 79
 
  • S. Okuda, T. Kojima, R. Taniguchi
    Osaka Prefecture University, Sakai
 
 

Transient phenomena induced by pulsed electron beams have been investigated with a pulse-radiolysis system with a 18 MeV S-band electron linac at Osaka Prefecture University (OPU). In our recent work the coherent transition radiation from the electron bunches of linac beams, which is highly intense pulsed light in a submillimeter to millimeter wavelength range, has been applied to absorption spectroscopy with an L-band electron linac in the Research Reactor Institute, Kyoto University. In these experiments the effect of intensity of the radiation has been observed for several kinds of matters. In this work a new pump-probe system has been developed to investigate the transient phenomena induced by the pulsed coherent radiation by improving the OPU pulse-radiolysis system. The transition radiation is emitted from an Al foil. A part of the coherent radiation is also used as probe light. The pulse lengths of the radiation are from 5 ns to 4 μs. The characteristics of the system have been measured and the system has been optimized. The coherent synchrotron radiation source is under preparation in order to obtain half-cycle light.

 
MOP019 CLIC Ring to Main Linac linac, booster, emittance, wakefield 88
 
  • F. Stulle, D. Schulte, J. Snuverink
    CERN, Geneva
  • A. Latina
    Fermilab, Batavia
  • S. Molloy
    Royal Holloway, University of London, Surrey
 
 

The low emittance transport had been identified as one of the feasibility issues for CLIC. We discuss beam dynamics challenges occurring in the beam lines of the RTML connecting the damping rings and the main linac. And we outline how these motivate design choices for the general RTML layout as well as its integration into the overall CLIC layout. Constraints originating from longitudinal dynamics and stabilization requirements of beam energy and phase at the main linac entrance are emphasized.

 
MOP028 The Asian Regional Proposal for A Single-Tunnel Configuration for The Conventional Facility site, klystron, positron, collider 115
 
  • A. Enomoto, S. Fukuda, K. Hosoyama, S. Imamura, H. Itoh, M. Miyahara, Y. Sugimoto, T. Tauchi
    KEK, Ibaraki
 
 

The international linear collider (ILC) project is about to meet the technical design phase 2, of which the goal is to establish a realistic design by the end of 2012. Single-tunnel accelerator configuration is one of the most essential improvements to reduce the construction costs. The original design involves two tunnels which house the accelerator cavities and the power supplies separately, having such advantages as we can enter the power-supply tunnel even during beam operation. Although the single tunnel configuration sacrifices these functions, it saves big tunnel construction costs. The Asian team is studying a regional single-tunnel accelerator configuration to match the Asian site feature in conjunction with a compact high-level RF scheme called distributed RF system (DRFS). The design concepts have been developed by a conventional facility working group in the advanced accelerator association (AAA) which involves a collaboration among academic, industrial, and political communities in Japan. Not only cost reduction but also functional impacts of tunnel configuration on things such as life safety are discussed in this paper.

 
MOP029 S0-studies on ICHIRO 9-cell Cavities in Collaboration with KEK and Jlab cavity, HOM, superconductivity, cathode 118
 
  • F. Furuta, K. Saito
    KEK, Ibaraki
  • G.V. Eremeev, R.L. Geng
    JLAB, Newport News, Virginia
  • T. Konomi
    Sokendai, Ibaraki
 
 

In 2008, KEK and Jlab did the collaboration of S0-study on ICHIRO 9-cell #5 which has no end groups on beam tubes. As S0 tight loop test, surface treatments and vertical tests were repeated on ICHIRO#5 at both of Jlab and KEK. Maximum gradients of 36.5MV/m at Jlab and 33.7MV/m at KEK were achieved so far. In this year, 2010, KEK and Jlab started new S0-study collaboration on ICHIRO 9cell #7 which has full end groups on beam tubes. ICHIR#7 was already sent to Jlab and VT as received was done. We will report the results of tight loop tests at Jlab.

 
MOP034 Observation of Ozone Explosion of Liquid Nitrogen Induced by Irradiation with Electron Linear Accelerator radiation, target, neutron, photon 130
 
  • R. Taniguchi, N. Ito, T. Kojima, S. Okuda
    Osaka Prefecture University, Sakai
 
 

A pulsed electron radiography system has been developed, which consisted of an electron linear accelerator, a scintillation screen and a high sensitivity image sensor. The system was capable for high speed strobo-imaging by the use of the pulse feature of the electron beam with the pulse width about a few micro-second. On the other hand, the characteristics of electron images were different from X-ray images and neutron images. Absorption behavior of energetic electrons in materials is Bragg-like rather than exponential. Therefore, a high contrast transparent image was obtained by modulating of energy of the electron beam. By the use of this system and utilizing these features, we observed successfully an ozone explosion phenomenon of liquid nitrogen induced by electron irradiation, which has been considered to be a serious problem in material irradiation experiments.

 
MOP035 Transient Beam Loading Compensation in L-band Traveling-wave Accelerating Structure with Intense Electron Beam beam-loading, injection, klystron, gun 133
 
  • S.H. Kim, M.-H. Cho, S.D. Jang, W. Namkung, S.J. Park, H.R. Yang
    POSTECH, Pohang, Kyungbuk
  • K.H. Chung, K. Lee
    KAPRA, Cheorwon
  • J.-S. Oh
    NFRI, Daejon
  • Y.G. Son
    PAL, Pohang, Kyungbuk
 
 

An intense L-band electron linac is now being commissioned at ACEP (Advanced Center for Electron-beam Processing in Cheorwon, Korea) for irradiation applications. It is capable of producing 10-MeV electron beams with the 30-kW average beam power. The constant-impedance accelerating structure is operated under fully-beam-loaded condition with the RF power of peak 25 MW and the beam current of 1.45 A. The total attenuation coefficient of the structure is 0.17 and the RF filling time is 0.9 μs along the 2.3-m accelerating structure. To suppress the energy spread due to the transient beam loading effect, we consider three methods: modulating the beam current amplitude, modulating the RF amplitude, and adjusting the beam injection time. In this paper, we calculate the transient beam energy numerically for the above cases. We also propose the actual compensation method.

 
MOP036 Beam Commissioning of C-band Standing-wave Accelerator for X-ray Source linac, coupling, cavity, gun 136
 
  • H.R. Yang, M.-H. Cho, S.D. Jang, S.H. Kim, W. Namkung, S.J. Park
    POSTECH, Pohang, Kyungbuk
  • K.H. Chung, K. Lee
    KAPRA, Cheorwon
  • J.-S. Oh
    NFRI, Daejon
 
 

A C-band standing-wave electron linac for a compact X-ray source is now being commissioned at ACEP (Advanced Center for Electron-beam Processing in Cheorwon, Korea). It is designed to produce 4-MeV electron beam with pulsed 50-mA, using a 5-GHz RF power generated by a magnetron with pulsed 1.5 MW and average 1.2 kW. The accelerating structure is a bi-periodic and on-axis-coupled one operated with π/2-mode standing-waves. It is consisted of 3 bunching cells, 6 accelerating cells and a coupling cell. As a result of measurements, the beam energy is almost 4 MeV. In this paper, we present the design details and the commissioning status.

 
MOP043 HITRAP - A Decelerator for Heavy Highly-charged Ions ion, rfq, quadrupole, injection 151
 
  • F. Herfurth, W.A. Barth, G. Clemente, L.A. Dahl, P. Gerhard, M. Kaiser, H.J. Kluge, N. Kotovski, C. Kozhuharov, M.T. Maier, W. Quint, A. Sokolov, T. Stöhlker, H. Vormann, G. Vorobjev
    GSI, Darmstadt
  • O.K. Kester
    NSCL, East Lansing, Michigan
  • J. Pfister, U. Ratzinger, A.C. Sauer, A. Schempp
    IAP, Frankfurt am Main
 
 

Heavy, highly-charged ions (HCI) with only one or few electrons are interesting systems for precision experiments as for instance tests of the theory of quantum electrodynamics (QED). To achieve high precision, kinetic energy and spatial position of the ions have to be well controlled. This is in contradiction to the production process that employs stripping of electrons at high energies by sending relativistic highly-charged ions with still many electrons through matter. In order to match the production at 400 MeV/u with the requirements of the experiments - stored and cooled HCI at low energy - the linear decelerator facility HITRAP has been built at the experimental storage ring (ESR) at GSI in Darmstadt. The ions are first decelerated in the ESR from 400 to 4 MeV/u, cooled and extracted. The ion beam phase spaces are then matched to an IH-structure, decelerated from 4 to 0.5 MeV/u before a 4-rod RFQ reduces the energy to 6 keV/u. Finally, the HCI are cooled in a Penning trap to 4 K. Extensive ion optical calculations were performed and in recent tests up to one million highly-charged ions have been decelerated from 400 MeV/u to 0.5 MeV/u.

 
MOP045 Efficiency and Intensity Upgrade of the ATLAS Facility rfq, cavity, ion, cryomodule 157
 
  • P.N. Ostroumov, R.V.F. Janssens, M.P. Kelly, S.A. Kondrashev, B. Mustapha, R.C. Pardo, G. Savard
    ANL, Argonne
 
 

ANL Physics Division is pursuing a major upgrade of the ATLAS National User Facility. The overall project will dramatically increase the beam current available for the stable ion beam research program, increase the beam intensity for neutron-rich beams from Californium Rare Isotope Breeder Upgrade (CARIBU) and improve the intensity and purity of the existing in-flight rare isotope beam (RIB) program. The project will take place in two phases. The first phase is fully funded and focused on increasing the intensity of stable beams by a factor of 10. This will be done using a new normal conducting, CW RFQ accelerator and replacing three cryostats of split-ring resonators with a single new cryostat of high-performance quarter-wave resonators. To further increase the intensity for neutron-rich beams, we have started development of a high-efficiency charge breeder for CARIBU based on an Electron Beam Ion Source. The goal of the proposed second phase will be to increase the energies and intensities of stable beams, as well as, increase the efficiency and beam current for CARIBU and in-flight RIB beams. The focus of this paper is on innovative developments for Phase I of the project.

 
MOP062 Linac followed by an Electron Cooler to Provide a Short Bunch Proton Beam proton, linac, extraction, beam-cooling 196
 
  • A. Noda, H. Souda, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • T. Fujimoto, S.I. Iwata, S. Shibuya
    AEC, Chiba
  • K. Noda, T. Shirai
    NIRS, Chiba-shi
 
 

Proton beams accelerated by an RFQ and a DTL with resonant frequency of 433 MHz,are electron cooled after injection into a storage ring, S-LSR and fast extracted to a beam irradiation target. Short pulse duration around 3.5 ns is expected for the 7 MeV proton beam with the intensity of 1.4 x 108 [1]. This beam is to be utilized for irradiation of biological cells in order to investigate Radio Biological Effectiveness of proton beam with a very high peak intensity for the purpose of quantitative verification of the recent report on the DNA double strand breaking with the use of short-pulse laser-produced proton beam [2]


[1] T. Fujimoto et al., Nucl. Instr. and Meth. Phys. Res. A588 (2008) 330-335.
[2] A. Yogo et al., Appl. Phys. Lett. 94 (2009) 181502.

 
MOP064 R&D of C Band Accelerating Structure at SINAP simulation, controls, linac, FEL 199
 
  • W. Fang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai
  • D.C. Tong
    TUB, Beijing
 
 

A compact hard X-ray FEL facility is on plan now at Shanghai Institute of Applied Physics (SINAP). This facility will be located close to Shanghai Synchrotron Radiation Facility(SSRF) which is a 3rd generation light source in China, in order to control the overall length less than 650m, this facility asks a compact linac with high gradient accelerating structure. C-band (5712MHz) accelerating structure is a compromised and good option for this compact facility. R&D of a C-band (5712MHz) high gradient traveling-wave accelerating structure has been in progress at Shanghai Institute of Applied Physics (SINAP). The structure is consisted of 53 regular disk-loaded cells and two waveguide couplers, and its length is about one meter. This paper introduces the study of the accelerating structure design method, its experimental model and the preliminary results of the RF cold test of the model structure.

 
MOP066 Numerical Modeling of Arcs in Accelerators plasma, vacuum, laser, acceleration 205
 
  • J. Norem, Z. Insepov, Th. Proslier
    ANL, Argonne
  • S. Mahalingam, S.A. Veitzer
    Tech-X, Boulder, Colorado
 
 

We are developing a model of arcing to explain breakdown phenomena in high-gradient rf systems used for particle accelerators. This model assumes that arcs develop as a result of mechanical failure of the surface due to electric tensile stress, ionization of fragments by field emission, and the development of a small, dense plasma that interacts with the surface primarily through self sputtering and terminates as a unipolar arc capable of producing field emitters with high enhancement factors. We are modeling these mechanisms using Molecular Dynamics (mechanical failure, Coulomb explosions, self sputtering), Particle-In-Cell (PIC) codes (plasma evolution), mesoscale surface thermodynamics (surface evolution), and finite element electrostatic modeling (field enhancements). We believe this model may be more widely applicable and we are trying to constrain the physical mechanisms using data from tokamak edge plasmas.

 
MOP069 Thermal Fatigue of Polycrystalline Copper in CLIC Accelerating Structures: Surface Roughening and Hardening as a Function of Grain Orientation laser, damping, radio-frequency, vacuum 214
 
  • M. Aicheler
    CERN, Geneva
 
 

The accelerating structures of CLIC will be submitted to 2 x 1010 thermal-mechanical fatigue cycles, arising from Radio Frequency (RF) induced eddy currents, causing local superficial cyclic heating. In order to assess the effects of superficial fatigue, high temperature annealed OFE Copper samples were thermally fatigued with the help of pulsed laser irradiation. They underwent postmortem Electron Backscattered Diffraction (EBSD) measurements andμhardness observations. Previous work has confirmed that surface roughening depends on the orientation of near-surface grains*,**. It is clearly observed that, through thermal cycling, the increase of hardness of a crystallographic direction is related to the amount of surface roughening induced by fatigue. Near-surface grains, oriented [1 0 0] with respect to the surface, exhibiting very low surface roughening, show limited hardening whereas grains oriented in [1 1 0], exhibiting severe surface roughening, show the most severe hardening. Consistently, surface roughening and hardening measured on [1 1 1] direction lie between the values measured for the other directions mentioned.


* Aicheler M et al.; 2010; Submitted to Int. Journal of Fatigue
** Aicheler M; 2009, Journal of Physics: Conference Series, Proceedings of ICSMA15

 
MOP081 The PITZ CDS Booster Cavity RF Tuning and Start of Conditioning cavity, booster, vacuum, coupling 241
 
  • V.V. Paramonov, A. Naboka
    RAS/INR, Moscow
  • A. Donat, L. Jachmann, W. Köhler, M. Krasilnikov, J. Meissner, D. Melkumyan, M. Otevrel, B. Petrosyan, J. Schultze, F. Stephan, G. Trowitzsch, R.W. Wenndorff
    DESY Zeuthen, Zeuthen
  • K. Flöttmann
    DESY, Hamburg
  • D. Richter
    HZB, Berlin
 
 

The DESY PITZ booster cavity, based on the Cut Disk Structure (CDS), is completed in construction. The L-band normal conducting cavity is intended to operate with accelerating rate up to 12.5 MV/m and RF pulse length up to 800 mks to increase the electron bunch energy in the PITZ facility at 20 MeV. The cavity was vacuum conditioned to reduce the out-gassing rate for operation in the facility with photo cathodes. The cavity is mounted in the PITZ tunnel and RF conditioning is started. The results of RF tuning before and after cavity brazing, together with first results of conditioning, are presented.

 
MOP091 A Digital Low Level RF Control System for the S-DALINAC cavity, controls, low-level-rf, superconducting-cavity 268
 
  • M. Konrad, U. Bonnes, C. Burandt, R. Eichhorn, N. Pietralla
    TU Darmstadt, Darmstadt
 
 

The superconducting cavities of the S-DALINAC have a high loaded quality factor and are very susceptible to microphonics. To stabilize the amplitude and phase of the cavities' fields an analog control system has been used for 20 years. To improve the stability and the availability of the low level RF control system it is currently replaced by a digital one. The 3 GHz signals coming from the cavities are converted down to the base band using hardware I/Q demodulators. The base band signals are digitized by ADCs and fed into an FPGA. This FPGA contains a custom CPU which executes the code implementing the control algorithm. The computed control signal is I/Q modulated before it is send to the cavity again. The superconducting cavities are operated with a self-excited loop algorithm whereas a generator driven algorithm is used for the low Q normal conducting bunching cavities. A 6 GHz RF board allows the operation of a new 2f buncher. Parameters can be adjusted via an EPICS IOC running on a standard PC. All signals from the FPGA can be monitored in realtime by the operator.

 
MOP102 Space Charge Lens for Focusing Heavy Ion Beams space-charge, ion, plasma, emittance 298
 
  • K. Schulte, M. Droba, O. Meusel, U. Ratzinger
    IAP, Frankfurt am Main
 
 

Space charge lenses use a confined electron cloud for the focusing of ion beams. Due to the electric space charge field, focusing is independent of the particle mass. For this reason the application of the space charge lens especially in the field of heavy ion beams is advantageous. Moreover, the trapped non neutral plasma cloud compensates the space charge forces of the ion beam. The focusing strength is given by the confined electron density whereas the density distribution influences the mapping quality of the space charge lens. An important parameter for the focusing capability of the space charge lens is besides the homogeneous electron distribution a high electron density. In ongoing theoretical and experimental work methods have been developed to determine the most important parameters like electron temperature and electron density distribution for an optimized lens design. Based on the experimental results a new space charge lens has been designed to focus low energy heavy ion beams like 2,4 AkeV U4+ at the low energy transport section into the GSI High Current Injector. Experimental results will be presented and compared with numerical simulations.


*W. Barth, "THE INJECTOR SYSTEMS OF THE FAIR PROJECT", LINAC08, Victoria, BC, Canada

 
MOP110 High Gradient Wakefield Acceleration (~ GV/m) in Structures: Goals of the Upgraded Argonne Wakefield Accelerator Facility (AWA) wakefield, gun, linac, acceleration 319
 
  • M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
    ANL, Argonne
  • S.P. Antipov, C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio
 
 

New technology needs to be developed for future compact linear colliders. The AWA Facility is dedicated to the study of advanced accelerator concepts towards this goal. The facility uses high charge short electron bunches to drive wakefields in dielectric loaded structures as well as in metallic structures (iris loaded, photonic band gap, etc). Accelerating gradients as high as 100 MV/m have been reached in dielectric loaded structures, and RF pulses of up to 44 MW have been generated at 7.8 GHz. In order to reach higher accelerating gradients, and also be able to generate higher RF power levels, several facility upgrades are underway: a new RF gun with a higher QE photocathode; a witness beam to probe the wakefields; additional klystrons and linac structures to bring the beam energy up to 75 MeV. The drive beam will consist of bunch trains of up to 32 bunches of 60 nC, corresponding to a beam power of 6 GW. The goal of future experiments is to reach accelerating gradients of several hundred MV/m and to extract RF pulses with GW power level. A key advantage of wakefield acceleration in structures is the ability to act on electrons and positrons in basically identical fashion.

 
MOP111 High Brightness Electron Beam Focusing System for an X-ray Generator simulation, gun, focusing, target 322
 
  • T. Sakai, M. Ikeda, S. Ohsawa, N. Sakabe, T. Sugimura
    KEK, Ibaraki
 
 

A new type of rotating anticathode X-ray generator has been developed, in which the electron beam up to 120keV irradiates the inner surface of a U-shaped Cu anticathode. A high-flux electron beam is obtained by optimizing the geometry of the combined function bending magnet. In order to minimize the sizes of the X-ray source, the electron beam is focused in a short distance by the combined function bending magnet, of which geometrical shape was determined by simulation with the codes of Opera-3D, General Particle Tracer (GPT) and CST STUDIO. The result of simulation clearly shows that the role of combined function in the bending magnet and the steering magnet is important to focus the beam in small sizes. FWHM sizes of the beam were predicted by simulation to be 0.45mm (horizontal) and 0.05mm (vertical) for a beam of 120keV and 75mA of which effective brilliance is about 500kW/mm2 with the supposition of a two-dimensional Gaussian distribution. The beam focus sizes on the target will be verified in the experiments by using the high-voltage power supply for the X-ray generator improved from 60kV to 120kV and 75mA.

 
MOP113 Multipacting Simulation of the Demountable Damped Cavity cavity, simulation, HOM, coupling 328
 
  • T. Konomi
    Sokendai, Ibaraki
  • F. Furuta, K. Saito
    KEK, Ibaraki
 
 

We have designed Demountable Damped Cavity (DDC) as an ILC R&D. DDC has an axial symmetric structure, the coaxial waveguide HOM coupler and absorber at the end of beam pipe of SRF cavity. It is also demountable structure. These structures are expected to bring better cavity performance. However, DDC have many parallel faced surfaces and the multipacting might be a concerned issue. We have simulated MP on the DDC with CST-Studio and found MP could be not serious issue. In this paper we will report the simulation result in detail.

 
TU101 Overview of FELs under Construction Including FELs at Fermi Elettra, SPRing8 and Frascati SPARC FEL, emittance, undulator, linac 337
 
  • G. Penco
    ELETTRA, Basovizza
 
 

This talk will report the present status of the worlwide FEL projects under construction including FELs at Fermi Elettra, SPRing8 and Frascati SPARC

 

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Slides

 
TU102 Overview of Proposals for Major FEL Facilities FEL, linac, undulator, gun 342
 
  • H.-H. Braun
    PSI, Villigen
 
 

The X-ray FEL facilities in an advanced stage of planning worldwide can be grouped in two categories. Those with normal conducting driver linacs aiming to bring the XFEL technology, after the impressive feasibility prove at LCLS, to regional user communities at affordable cost, and those with superconducting driver linacs capable to serve several photon hungry users simultaneously. The talk will review the rationales, technical choices and status of the main proposals and discuss some key R&D issues.

 

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Slides

 
TU103 Worldwide ERL R&D Overview Including JLAMP, BNL, and Cornell ERLs gun, SRF, linac, brightness 347
 
  • G. Neil
    JLAB, Newport News, Virginia
 
 

Energy Recovering Linacs have become an important approach to providing high brightness electron beams for photon production, nuclear physics research, and cooling ions. The technology takes advantage of the ability of superconducting rf cavities to accelerate high average current beams with low losses. After the desired interaction the electrons can be decelerated to low energy so as to minimize the required rf power and electrical draw. When this approach is coupled with advanced continuous wave injectors, very high power, ultra-short electron pulse trains of high brightness can be achieved. This talk will review the status of worldwide programs including the on-going BNL and Cornell efforts, the Novosibirsk Multipass ERL, ALICE at Daresbury, the KEK/JAEA ERL, and the Peking ERL among others. We will also touch on the prospects for proposed machines such as the JLAMP advanced ERL FEL efforts at Jefferson Lab designed to produce ultra-high brightness beams of photons in the 10-100 nanometer soft X-ray region.

 

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Slides

 
TUP004 Status of ERL and cERL Projects in Japan cavity, gun, laser, klystron 398
 
  • S. Sakanaka, H. Kawata, Y. Kobayashi
    KEK, Ibaraki
  • R. Hajima
    JAEA/ERL, Ibaraki
  • N. Nakamura
    ISSP/SRL, Chiba
 
 

Future light sources based on the Energy Recovery Linac (ERL) are expected to bring innovation to the synchrotron radiation (SR) science. Our Japanese collaboration team plans to construct a 5-GeV ERL which can produce super-brilliant and ultra-short pulses of SR as well as can be a driver for a proposed X-ray free-electron laser oscillator (X-FELO). In order to establish the key technologies for the ERL, we are conducting aggressive R&D efforts. Concerning our high-brightness photocathode DC electron gun, we succeeded to apply a DC high voltage of 500 kV through a support rod. Both cryomodules for the injector and the main-linac are also under development. In order to demonstrate reliable operations of such key technologies, we plan to construct the Compact ERL (cERL) at KEK. During FY2009, we prepared the infrastructure for the cERL which includes renovation of the building (the East Counter Hall), renovation of cooling-water system and electrical substation, installation of liquid helium refrigerator, and installation of a part of the rf source. In this paper, we present up-to-date status of the ERL and the Compact ERL projects in Japan.

 
TUP009 First Commissioning Experience at the SwissFEL Injector Test Facility laser, gun, emittance, solenoid 410
 
  • T. Schietinger, M. Aiba, B. Beutner, M. Dach, A. Falone, R. Ganter, R. Ischebeck, F. Le Pimpec, N. Milas, P. Narang, G.L. Orlandi, M. Pedrozzi, S. Reiche, C. Vicario
    PSI, Villigen
 
 

The Paul Scherrer Institute is commissioning a 250 MeV injector test facility in preparation for the SwissFEL project. Its primary purpose is the demonstration of a high-brightness electron beam meeting the specifications of the SwissFEL main linac. At the same time it is advancing the development and validation of the accelerator components needed for the realization of the SwissFEL facility. We report the results of the first commissioning phase, which includes the gun section of the injector up to 7 MeV electron energy. Electrons are generated by a 2.6-cell laser-driven photocathode RF gun operating at 3 GHz followed by an emittance compensating focusing solenoid. The diagnostic system for this phase consists of a spectrometer dipole, a series of screens and beam position monitors and several charge measuring devices. Slit and pinhole masks can be inserted for phasespace scans and emittance measurements. The completion of the entire injector facility proceeds in three stages, culminating with the integration of the magnetic compression chicane expected for early 2011.

 

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Poster

 
TUP011 Layout of the PITZ Transverse Deflecting System for Longitudinal Phase Space and Slice Emittance Measurements klystron, diagnostics, high-voltage, emittance 416
 
  • L.V. Kravchuk, V.V. Paramonov
    RAS/INR, Moscow
  • A. Anisimov, M.V. Lalayan, A.Yu. Smirnov, N.P. Sobenin
    MEPhI, Moscow
  • D. Churanov, E.V. Ivanov, S.V. Kutsaev, M. Urbant, A.A. Zavadtsev, D.A. Zavadtsev
    Nano, Moscow
  • A. Donat, W. Köhler, M. Krasilnikov, J. Meissner, M. Pohl, J. Schultze, F. Stephan, G. Trowitzsch, R.W. Wenndorff
    DESY Zeuthen, Zeuthen
  • C. Gerth, M. Hoffmann, M. Hüning
    DESY, Hamburg
 
 

Transverse Deflecting Systems are designated for longitudinal beam diagnostics of ultra-short electron bunches in modern FEL projects. At the European XFEL, Transverse Deflecting Systems are foreseen at three locations. A prototype of the TDS in the injector of the European XFEL will be installed at PITZ which is identical in terms of deflecting structure, low-level RF system and powerful RF hardware. This PITZ TDS has the aim to prove the required performance for all TDS subsystems as well as serve as a diagnostics tool for PITZ. Results of the test cells measurements of a S-band travelling wave structure are presented, showing very good agreement with calculated parameters. RF power supply system, including 3 MW klystron and other RF hardware, is described. Solid state 130 kV Marx modulator has been developed for the klystron feeding. 10 kV module of the modulator has been built and tested. The modulator allows for high voltage shutdown within pulse.

 
TUP012 sFLASH - First Results of Direct Seeding at Flash undulator, FEL, laser, photon 419
 
  • J. Bödewadt, A. Azima, F. Curbis, H. Delsim-Hashemi, M. Drescher, E. Hass, U. Hipp, Th. Maltezopoulos, V. Miltchev, M. Mittenzwey, M. Rehders, J. Roßbach, J. Rönsch-Schulenburg, R. Tarkeshian, M. Wieland
    Uni HH, Hamburg
  • S. Bajt, S. Düsterer, K. Honkavaara, T. Laarmann, H. Schlarb
    DESY, Hamburg
  • R. Ischebeck
    PSI, Villigen
  • S. Khan
    DELTA, Dortmund
 
 

The free-electron laser facility FLASH at DESY (Hamburg) was upgraded during a five-month shutdown in winter 2009. Part of this upgrade was the installation of a direct seeding experiment in the XUV spectral range. Beside all components for transport and diagnostics of the photon beam in and out of the accelerator environment, a new 10 m long variable-gap undulator was installed upstream of the existing FLASH undulator system. The seed pulses are generated within a noble-gas jet by focusing 40 fs long Ti:Sa laser pulses into it resulting a comb of higher harmonics. In the first phase of the experiment the 21st harmonic of the 800 nm drive laser will be used to seed the FEL process. The commissioning of the experiment has started in April and the first results are expected after the FLASH commissioning period mid of summer 2010. The experimental setup and the commissioning procedures as well as first result will be presented.

 
TUP038 Matter-Radiation Interactions in Extremes linac, proton, klystron, controls 485
 
  • R.W. Garnett, M.S. Gulley
    LANL, Los Alamos, New Mexico
 
 

LANSCE has been the centerpiece of large-scale science at Los Alamos National Laboratory for many decades. Recently, funding has been obtained to ensure continued reliable operation of the LANSCE linac and to allow planning to enable the first in a new generation of scientific facilities for the materials community. The emphasis of this new facility is "Matter-Radiation Interactions in Extremes" (MaRIE) which will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges. MaRIE will provide the tools scientists need to develop next-generation materials that will perform predictably and on-demand for currently unattainable lifetimes in extreme environments. The MaRIE facility is based on a high-power upgrade to the existing LANSCE proton linac, a new electron linac and associated X-ray FEL to provide additional probe beams, and new experimental areas. A conceptual description of this new facility and its requirements will be presented.

 
TUP089 Transverse Emittance Measurements in MEBT at SNS emittance, coupling, linac, ion 614
 
  • A.P. Zhukov, A.V. Aleksandrov, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee
 
 

The latest modifications of the MEBT emittance scanner and the test results are presented. The scanner consists of a slit and harp placed in the MEBT section of SNS Linac with H- energy of 2.5 MeV. It was initially commissioned during the early days of SNS. The initial design allowed to get information about beam core but was incapable of getting precise data about halo. Several improvements in hardware and software were performed recently. They significantly increased signal to noise ratio, reduced harp wires electron coupling and increased scan speed. The latest measurements with the new system show a good agreement with the simulation results from simple models.

 
TUP090 Development of a Bunch Length Detector optics, proton, vacuum, resonance 617
 
  • J.Y. Kim, H.-C. Bhang, D.G. Kim
    SNU, Seoul
  • J.-W. Kim
    NCC, Korea, Kyonggi
 
 

A bunch length detector has been designed and constructed, which can measure current distributions inside the beam bunch. The device measures secondary electrons that are emitted when the beam hits a negatively biased thin target wire. Two main components of the device are an rf deflector to deflect secondary electrons vertically in correlation with the rf time of the beam bunch, and microchannel plate to detect the electrons after spatial discrimination. Rf properties of the rf deflector were first numerically analyzed, and a full-scale cold model was built and tested using a network analyzer. Microchannel plate detector was tested using a beta-emitting isotope source. The electron optics were calculated to design the structure of the detector, and the actual detector will soon be constructed and tested using a cw proton beam from a cyclotron.

 
TUP095 Standard E-beam Diagnostics for the European XFEL cavity, diagnostics, undulator, FEL 632
 
  • D. Nölle
    DESY, Hamburg
 
 

The European XFEL is a 4th generation synchrotron radiation source, under construction in Hamburg. Based on different Free-Electron-Laser and spontaneous sources, driven by a 17.5 GeV superconducting accelerator, this international facility will provide several user stations with photons simultaneously. Due to superconducting technology high average as well as peak brilliance can be delivered. Flexible bunch pattern are possible for optimum tuning to the experiments demands. This paper will present the current status of the electron beam diagnostics. An overview of the entire system will be given, as well as details on the development of the main systems like BPM, charge and transmission diagnostics, beam size and beam loss monitor systems will be presented. Furthermore, results of first measurements with XFEL prototypes in FLASH will be shown.

 
TUP097 Methodical Studies for Tomographic Reconstruction As a Novel Method For Emittance Measurements At the PITZ Facility emittance, laser, lattice, quadrupole 638
 
  • G. Asova, M. Krasilnikov, J. Saisut, F. Stephan
    DESY Zeuthen, Zeuthen
  • G. Asova
    INRNE, Sofia
 
 

The Photo-Injector Test Facility at DESY in Zeuthen, PITZ, is dedicated to development of high brightness electron sources for linac-based FELs like FLASH and the European XFEL. A key parameter to judge on the beam quality for an FEL is the transverse phase space distribution, wherefrom the PITZ beamline is equipped with three Emittance Measurement Systems as the only dedicated to that apparatus. In 2010 the diagnostics has been upgraded with a module for tomographic reconstruction comprising three FODO cells, each surrounded by two observation screens. The anticipated advantages of tomographic measurements are improved resolution for low charge beams and ability to evaluate both transverse planes simultaneously. Major operational challenges are the low beam energies the module will be used with - 15 - 30 MeV, strong space charge effects for high bunch charges and, consequently, difficulties to match the beam into the optics of the lattice. This contribution presents studies on the performance of the module for different initial conditions as bunch charge and temporal laser pulse shape. Influence of residual noise on the quality of the reconstructed phase space is discussed.

 
TUP099 Coherent Diffraction Radiation as a Tool for Longitudinal Beam Profile Diagnostics at CTF3. target, radiation, background, simulation 644
 
  • K. Lekomtsev, G.A. Blair, G.E. Boorman, V. Karataev, M. Micheler
    JAI, Egham, Surrey
  • R. Corsini, T. Lefèvre
    CERN, Geneva
 
 

Compact Linear Collider (CLIC) is a multi-TeV electron-positron collider for particle physics based on an innovative two-beam acceleration scheme. The CLIC Test Facility 3 (CTF3, CERN) aims to demonstrate feasibility of this concept. The monitoring of a longitudinal profile will be very important for the CLIC. The optimization of the longitudinal charge distribution in a bunch is crucial for the maximisation of the luminosity and also for an optimal performance of a CLIC drive beam. A setup for the investigation of Coherent Diffraction Radiation (CDR) from targets with various configurations as a tool for non-invasive longitudinal electron beam profile diagnostics has been designed and installed in the CRM line of the CTF3 [1, 2]. In this report we present the status of the experiment and results on interferometric measurements of CDR from a single target configuration. Studies on downstream background contribution in the CRM line have been performed. Recently we have upgraded the system by installing a second target. In this report we shall also demonstrate the results on simulations of CDR spatial distribution from the two target configuration.


[1] M. Micheler et al., Longitudinal Beam Profile Measurements at CTF3 using CDR, PAC'09, "**".
[2] M. Micheler et al., Longitudinal beam profile monitor at CTF3 based on CDR, RREPS-09, "**".

 
TUP101 Wire Grid and Wire Scanner Monitors Design for the CERN LINAC 4 ion, linac, proton, scattering 650
 
  • F. Roncarolo, E. Bravin, M. Duraffourg, C. Dutriat, G.J. Focker, U. Raich, VC. Vuitton
    CERN, Geneva
  • B. Cheymol
    Université Blaise Pascal, Clermont-Ferrand
 
 

As part of the CERN LHC injector chain upgrade, LINAC4 will accelerate H- ions from 45 keV to 160 MeV. A number of wire grids and wire scanners will be used to characterize the beam transverse profile. This paper covers all monitor design aspects intended to cope with the required specifications. In particular, the overall measurement robustness, accuracy and sensitivity must be satisfied for different commissioning and operational scenarios. The physics mechanisms generating the wire signals and the wire resistance to beam induced thermal loads have been considered in order to determine the most appropriate monitor design in terms of wire material and dimensions.

 
TUP102 Phase Space Analysis at the SwissFEL Injector Test Facility emittance, background, gun, diagnostics 653
 
  • B. Beutner, R. Ischebeck, T. Schietinger
    PSI, Villigen
 
 

Phase I of the SwissFEL Injector Test Facility consists of a 2.6-cell S-band RF gun, a spectrometer, and a series of transverse beam diagnostic systems such as YAG screens, slit and pepper-pot masks. Its primary purpose is the demonstration of a high-brightness electron beam meeting the specifications of the SwissFEL main linac. Phase space characterization at beam energies up to 7 MeV, where space charge still dominates, is performed with YAG screens in combination with slit- and pinhole (pepper-pot) masks. Advanced image analysis is used to mitigate artefacts due to background, pixel readout noise, or dark current. We present our data analysis procedure for the slit scan method, with particular emphasis on image processing and its effect on the reconstructed emittance. Pepper-pot measurements using an independent analysis framework are used to cross-check the slit scan results.

 
TUP103 Profile Monitors for the SwissFEL Injector Test Facility emittance, radiation, target, cavity 656
 
  • R. Ischebeck, B. Beutner, G.L. Orlandi, M. Pedrozzi, T. Schietinger, V. Schlott, V.G. Thominet
    PSI, Villigen
 
 

The SwissFEL Injector Test Facility consists of an RF gun, an accelerating section for a final energy of 250 MeV, and two diagnostics sections. Transverse profiles of the electron beam can be recorded at 27 locations by imaging fluorescent crystals that can be inserted into the beam. At 21 of these, the fluorescent screens are complemented by optical transition radiation monitors and wire scanners. Here, we will evaluate the performance of transverse profile monitors experimentally and numerically and compare the measured profiles with a numerical model of the accelerator. Profile monitors are used in conjunction with a slit and a pepper pot to determine the transverse phase space distribution of the bunches. Experimental measurements at the SwissFEL Injector Test Facility will be presented.

 
TUP106 Development of Stripper Options for FRIB plasma, ion, linac, vacuum 662
 
  • F. Marti
    NSCL, East Lansing, Michigan
  • A. Hershcovitch, P. Thieberger
    BNL, Upton, Long Island, New York
  • Y. Momozaki, J.A. Nolen, C.B. Reed
    ANL, Argonne
 
 

The US Department of Energy Facility for Rare Isotope Beams (FRIB) at Michigan State University includes a heavy ion superconducting linac capable of accelerating all ions up to uranium with energies higher than 200 MeV/u and beam power up to 400 kW. To achieve these goals with present ion source performance it is necessary to accelerate simultaneously two charge states of uranium from the ion source in the first section of the linac. At an energy of approximately 17 MeV/u we plan to strip the uranium beam to reduce the voltage needed in the rest of the linac to achieve the final energy. Up to five different charge states are planned to be accelerated simultaneously after the stripper. The design of the stripper is a challenging problem due to the high power deposited (approximately one kW) in the stripper media by the beam in a small spot. To assure success of the project we have established a research and development program that includes several options: carbon or diamond foils, liquid lithium films, gas strippers and plasma strippers. We present in this paper a summary of the requirements and a general description of the status of the different options.

 
WE201 Operation and Upgrades of the LCLS FEL, linac, emittance, undulator 694
 
  • J.C. Frisch, R. Akre, J. Arthur, C. Bostedt, J.D. Bozek, A. Brachmann, P.H. Bucksbaum, R.N. Coffee, F.-J. Decker, Y.T. Ding, D. Dowell, S.A. Edstrom, P. Emma, A.S. Fisher, J.N. Galayda, A. Gilevich, J.B. Hastings, G.R. Hays, P. Hering, Z. Huang, R.H. Iverson, H. Loos, M. Messerschmidt, A. Miahnahri, S.P. Moeller, H.-D. Nuhn, D.F. Ratner, J.A. Rzepiela, D.C. Schultz, T.J. Smith, H. Tompkins, J.L. Turner, J.J. Welch, J. Wu, G. Yocky
    SLAC, Menlo Park, California
  • R.M. Bionta
    LLNL, Livermore, California
  • G. Pile
    ANL, Argonne
 
 

The LCLS FEL began user operations in September 2009, with photon energies from 800eV to 2 KeV and pulse energies above 2 mJ. Both long pulse (50-200 femtosecond FWHM) and short pulse (<10 femtosecond FWHM at 150 uJ) pulses were delivered at user request. In addition the FEL was operated at fundamental photon energies up to 10 KeV in preparation for hard X-ray experiments. FEL operating parameters, performance and reliability results will be presented, in addition to plans for upgrades to the facility.

 

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Slides

 
WE203 First Simultaneous Top-up Operation of Three Different Rings in KEK Injector Linac injection, linac, target, positron 703
 
  • M. Satoh
    KEK, Ibaraki
 
 

The KEK injector linac sequentially provides beams to four storage rings: a KEKB low-energy ring (LER) (3.5 GeV/positron), a KEKB high-energy ring (HER) (8 GeV/electron), a Photon Factory ring (PF ring; 2.5 GeV/electron), and an Advanced Ring for Pulse X-rays (PF-AR; 3 GeV/electron). So far, beam injection to the PF ring and PF-AR had been carried out twice a day, whereas the KEKB rings had been operated in the continuous injection mode (CIM) for keeping stored currents almost constant. The KEK linac upgrade project has started since 2004 so that the PF top-up and KEKB CIM can be operated at the same time. The goal is to inject the beams of different energy into the three independent rings in every 20 ms, where the common DC magnet settings are utilized for beams having different energy and charge, whereas different optimized rf phases are applied to each beam acceleration by using a fast low-level rf control up to 50 Hz. With this noble operation scheme, a simultaneous top-up operation for different three rings was achieved for the first time over the world, and has been stably in operation since last April. We report the operation scheme and status in detail.

 

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Slides

 
TH202 VECC/TRIUMF Injector for the e-Linac Project linac, cavity, TRIUMF, gun 727
 
  • V. Naik, A. Bandyopadhyay, A. Chakrabarti, S. Dechoudhury, M. Mondal
    DAE/VECC, Calcutta
  • F. Ames, R.A. Baartman, C.D. Beard, Y.-C. Chao, R.J. Dawson, P. Kolb, S.R. Koscielniak, R.E. Laxdal, M. Marchetto, L. Merminga, A.K. Mitra, T.C. Ries, I. Sekachev, V.A. Verzilov, F. Yan
    TRIUMF, Vancouver
  • D. Longuevergne
    UBC & TRIUMF, Vancouver, British Columbia
 
 

TRIUMF (Canada) and VECC (India) are both planning to use the photo-fission route for producing neutron-rich radioactive ion beams in their respective RIB programmes. With this common goal the two institutes have entered into a collaboration to jointly design and develop a superconducting 1.3GHz 50MeV, 10 mA, CW electron linac which will be used as the fission driver. The first phase of the e-Linac collaboration aims at the development, production and full technical and beam test of a 10MeV injector cryo module (ICM) which forms the front-end of the final linac. The design and technical development of the ICM will be presented.

 
TH304 Linear Induction Accelerators at the Los Alamos National Laboratory DARHT Facility target, dipole, induction, cathode 750
 
  • S. Nath
    LANL, Los Alamos, New Mexico
 
 

The Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory consists of two linear induction accelerators at right angles to each other. The First Axis, operating since 1999, produces a nominal 20-MeV, 2-kA single beam-pulse with 60-nsec width. In contrast, the DARHT Second Axis, operating since 2008, produces up to four pulses in a variable pulse format by slicing micro-pulses out of a longer 1.6-microseconds (flat-top) pulse of nominal beam-energy and -current of 17 MeV and 2 kA respectively. Bremsstrahlung radiation, shining on a hydro-dynamical experimental device, is produced by focusing the electron beam-pulses onto a high-Z target. Variable pulse-formats allow for adjustment of the pulse-to-pulse doses to record a time sequence of x-ray images of the explosively driven imploding mock device. In this talk, we present a sampling of the numerous physics and engineering challenges encountered and the solutions thereof that led to the present fully operational dual axes capability. First successful simultaneous use of both the axes for a hydrodynamic experiment was achieved in 2009.

 
THP007 Overview of the CERN LINAC4 Beam Instrumentation linac, diagnostics, emittance, instrumentation 770
 
  • F. Roncarolo, G. Bellodi, E. Bravin, B. Dehning, M. Duraffourg, G.J. Focker, D. Gerard, E.B. Holzer, LF. Lenardon, U. Raich, L. Søby, M. Sordet, J. Tan, G. Tranquille, VC. Vuitton, C. Zamantzas
    CERN, Geneva
  • B. Cheymol
    Université Blaise Pascal, Clermont-Ferrand
 
 

The CERN LINAC4 will represent the first upgrade of the LHC injection chain, by accelerating H- ions from 45 KeV to 160 MeV for charge-exchange injection into the PS Booster. In order to provide its safe and efficient commissioning and operation, a wide variety of beam diagnostics devices has been designed for installation at convenient locations all over the accelerator length and in the transfer line to the PS Booster. This paper gives an overview of all instrumentation devices, including those to measure beam position, transverse and longitudinal profile, beam current and beam loss. The well advanced status of the system design and the main instrument features are discussed.

 
THP011 First Beam Spectra of sc Third Harmonic Cavity at FLASH HOM, cavity, simulation, FEL 782
 
  • P. Zhang, R.M. Jones, I.R.R. Shinton
    UMAN, Manchester
  • N. Baboi, B. Lorbeer, P. Zhang
    DESY, Hamburg
  • T. Flisgen, H.-W. Glock, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock
 
 

Third harmonic superconducting cavities have been designed and fabricated by FNAL to minimise the energy spread along bunches in the FLASH facility at DESY. A module, consisting of four nine-cell 3.9 GHz cavities, has been installed in FLASH. The first measurement with beam excitation is presented, and the comparisons to transmission measurement without beam and simulations are made. Higher order modes (HOMs) are able to propagate to adjacent cavities through attached beam tubes. Modes from 1.3 GHz cavities in the module nearby also propagate into this module.


*Work supported by European Commission under the FP7 Research Infrastructures grant agreement No.227579.

 
THP015 A Review of the 1.3GHz Superconducting 9-Cell Cavity Fabrication for DESY cavity, HOM, higher-order-mode, linac 794
 
  • J. Iversen, R. Bandelmann, G. Kreps, W.-D. Möller, D. Proch, J.K. Sekutowicz, W. Singer
    DESY, Hamburg
 
 

Since 1993 DESY ordered 165 1.3GHz 9-cell superconducting cavities. The cavities have been developed for TeV-Energy Superconducting Linear Accelerator (TESLA) and are used in the linac of the Free Electron Laser in Hamburg (FLASH). The fabrication of all cavities was done in 9 production groups at industry. From the beginning the industrialization was carried out in close collaboration between DESY and the industry. From order to order the cavity design was optimized and the fabrication sequences were improved to realize stable and better cavity performance and to safe costs. Now a final cavity design for the European XFEL is defined. We summarize the development phases and design changes up to the final XFEL design. An outlook on the near future production of hundreds of cavities for XFEL based on our experience will be given.

 
THP018 Recent Results of 1.3 GHz 9-cell Superconducting Cavities in KEK-STF cavity, radiation, HOM, superconducting-cavity 800
 
  • Y. Yamamoto, H. Hayano, E. Kako, S. Noguchi, M. Satoh, T. Shishido, K. Umemori, K. Watanabe
    KEK, Ibaraki
 
 

MHI#10 and #11 cavities are measured in KEK-STF as the s0 plan for ILC. After these vertical tests, they will be sent to J-Lab and tested at least once there. Moreover, two new cavities without HOM coupler are fabricated and measured in STF, which are made by two new vendors (HITACHI and TOSHIBA). As the international collaboration, one cavity from IHEP in Beijing will be sent to KEK, optical inspected, high pressure rinsed and vertical tested. Although MHI#8 cavity for S1-Global reached 38MV/m, it could not achieve ILC specification (35MV/m, 0.8x109) due to the heavy field emission. To overcome this problem, the various tests were done in the stage of the surface treatment. For example, the EP parameters and the rinsing procedure were changed. In this report, the recent results of the vertical tests including the surface treatment in KEK-STF will be presented in detail.

 
THP022 Design Optimisation of the EURISOL Driver Low-beta Cavities cavity, vacuum, linac, TRIUMF 806
 
  • Y. Ma
    CIAE, Beijing
  • A. Facco, F. Scarpa
    INFN/LNL, Legnaro (PD)
 
 

The low-beta section of the EURISOL driver linac is based on 176 MHz superconducting half-wave resonators (HWR) with beta=0.09 and 0.16. These cavities are an evolution of the 352 MHz ones, previously developed in the same framework, having similar dimensions and components except for their length and rf frequency. They are characterized by a double wall, all niobium structure with light weight, good mechanical stability and a side tuner cooled by thermal conduction. The new 176 MHz Half-wave cavities design includes a removable tuner, which allows to improve tuning range, mechanical stability and accessibility to the cavity interior. A beta=0.13 cavity, which could be suitable for linacs like the SARAF one, was also designed with the same concepts. Design characteristics and expected performance will be presented and discussed.

 
THP035 Prototyping Activities of Low-beta SRF Cavity for the PEFP Proton Linac Extension cavity, linac, niobium, SRF 833
 
  • H.S. Kim, Y.-S. Cho, H.-J. Kwon
    KAERI, Daejon
 
 

A superconducting RF cavity with a geometrical beta of 0.42 and a resonant frequency of 700 MHz has been under consideration for an extension program of Proton Engineering Frontier Project (PEFP) to accelerate the proton beam above 100 MeV. A five-cell prototype was fabricated and tested to confirm the fabrication procedure and to check the RF and mechanical properties. High RRR niobium sheets (RRR > 250) were used for the cavity material, whereas reactor grade niobium and NbTi were used for the beam pipe region and the flange, respectively. Double-ring stiffening structure was adopted to reduce the Lorentz force detuning effect. For the vertical test of the prototype cavity, a cryostat with operating temperature of 4.2 K was designed and fabricated. The cryostat was thermally insulated with 40 layers of MLI and the vacuum jacket and equipped with temperature monitors and liquid level sensors. The RF system for driving the cavity is based on PLL to track the resonance condition. The status of the prototype development and the vertical test results will be presented in this paper.

 
THP041 An Update on the Study of High-Gradient Elliptical SRF Cavities at 805 MHz for Proton and Other Applications cavity, SRF, vacuum, superconducting-cavity 851
 
  • T. Tajima, W.B. Haynes, F.L. Krawczyk, M.A. Madrid, R.J. Roybal, E.I. Simakov
    LANL, Los Alamos, New Mexico
  • W.A. Clemens, K. Macha, R. Manus, R.A. Rimmer, L. Turlington
    JLAB, Newport News, Virginia
 
 

An update on the study of 805 MHz elliptical SRF cavities that have been optimized for high gradient will be presented. An optimized cell shape, which is still appropriate for easy high pressure water rinsing, has been designed with the ratios of peak magnetic and electric fields to accelerating gradient being 3.75 mT/(MV/m) and 1.82, respectively. A total of 3 single-cell cavities have been fabricated and tested with various conditions. In addition, a 6-cell cavity design has been completed including multipacting simulations.

 
THP042 Studies on Superconducting Thin Films for SRF Applications* cavity, SRF, klystron, cryogenics 854
 
  • T. Tajima, L. Civale, T. Doi, G.V. Eremeev, N.F. Haberkorn, M. Hawley, A. Matsumoto, R.K. Schulze, A.T. Zocco
    LANL, Los Alamos, New Mexico
  • V.A. Dolgashev, J. Guo, D.W. Martin, S.G. Tantawi, C. Yoneda
    SLAC, Menlo Park, California
  • B. Moeckly
    STI, Santa Barbara, California
 
 

In order to overcome the theoretical limit of ~200 mT peak surface magnetic field for niobium SRF cavities, an idea of coating multi-layer thin film superconductors separated with thin dielectric layers has been suggested. We are testing MgB2, NbN and NbC as candidates for the realization of this idea. The results of surface characterization, Auger depth profile, DC magnetization measurements with SQUID, low- and high-field measurements with a TE013-like mode copper cavity coupled with a 11.4 GHz short-pulse Klystron will be presented.

 
THP053 High Power RF for TRIUMF Injector Cryomodule and Elinac cavity, linac, klystron, cryomodule 872
 
  • A.K. Mitra, S. Calic, S.R. Koscielniak, R.E. Laxdal
    TRIUMF, Vancouver
 
 

A 500 kW electron linear accelerator is being proposed at TRIUMF for radioactive ion beam production to support existing rare isotope facility. Present design consists of 100 keV thermionic gun, a normal conducting buncher, an injector module and main linac modules. The design energy is 50 MeV with 10 mA beam current. The linac will operate in cw mode using 1.3 GHz superconducting technology. The injector cryomodule (ICM), uses a nine-cell TESLA type cavity operating at 2 degree Kelvin. The front end of the ICM has a room temperature buncher and also has two superconducting capture cavities which are housed in the same cryomodule as the accelerating multi-cell cavity. Solid state amplifiers are proposed to be used for the buncher and the capture cavities. A 30 kW 1.3 GHz IOT, operating at cw will be used to drive the nine-cell cavity of the ICM. The rf power will be divided into two equal parts and fed to two TTF III type couplers. The same couplers are intended to be used for the remaining accelerator cavities of the e-linac. The e-linac is being proposed to be built in stages. High power Klystrons are to be used to provide rf power to the accelerating cavities.

 
THP055 Multipactor Simulations of the SPL Power Coupler multipactoring, simulation, cavity, proton 878
 
  • G. Burt, P.K. Ambattu, A.C. Dexter
    Cockcroft Institute, Lancaster University, Lancaster
  • R. Calaga
    BNL, Upton, Long Island, New York
  • E. Montesinos
    CERN, Geneva
 
 

Multipactor is a limiting factor in many RF power couplers. The SPL coupler is proposed to have a conical matching section between the window and the coaxial section however this section must be checked for multipactor. Multipactor simulations of the coupler up to a few MW's of power were performed using a variety of different codes and the results were compared. Simulations were performed in the conical and straight coaxial sections.

 
THP068 Compact Solid State Direct Drive RF Linac Experimental Program cavity, impedance, injection, resonance 905
 
  • O. Heid, T.J.S. Hughes
    Siemens AG, Healthcare Technology and Concepts, Erlangen
 
 

An RF accelerator driver concept is introduced, which integrates a distributed solid-state RF power source with the RF resonator. The resulting structure plays a double role as RF combiner and particle accelerating structure [1]. The key enabling technologies are Silicon Carbide RF transistors and a power combiner concept which includes insulating parallel cavities to ensure consistent RF current injection. An experimental direct drive lamda/4 cavity with a power rating of 500kW at 150MHz has been constructed. The Direct Drive RF power source consists of 64 RF modules constructed from Silicon Carbide vJFETs, radial power combiner and isolation cavity. The initial results from the integration of the direct drive RF source are presented. These results demonstrate experimentally for the first time the validity of the direct drive concept and the key characteristics of such a drive.


[1] O. Heid, T Hughes. "Compact Solid State Direct Drive RF LINAC" presented at IPAC 2010, Kyoto, Japan.

 
THP087 Simulation of Cathode Back-bombardment in a 100 MHz Thermionic RF Gun cathode, gun, wiggler, simulation 944
 
  • M. Borland, X.W. Dong
    ANL, Argonne
 
 

A 100 MHz thermionic rf gun is under consideration as the electron source for the X-ray Free Electron Laser Oscillator*. Because the source must operate continuously, back-bombardment of the cathode is a serious concern. We present results of simulations of back-bombardment, as well as strategies for reducing the back-bombardment power on the cathode.


*K. J. Kim et al., Phys. Rev. Lett. 100, 244802 (2008)

 
THP090 Modeling A Table Top Storage Ring For A Compact Light Source Using Electromagnetic Field Simulation Tools storage-ring, injection, synchrotron, cavity 953
 
  • T. Roggen, H. De Gersem, J.P. Locquet, B. Masschaele
    KU Leuven, Kortrijk
  • M. Zhukova
    Tomsk Polytechnic University, Nuclear Physics Institute, Tomsk
 
 

Large synchrotron radiation facilities have become one of the most powerful instruments for research today. All over the world new facilities are being constructed or designed. The biggest disadvantage of a large synchrotron facility is that the scientific experiments, which are often very sensitive and complex, have to be performed in a dedicated place, sometimes far away from the researcher's home laboratory. Promising compact synchrotron radiation sources, that fit in a typical research lab, have been proposed recently. In this paper results are presented of an initial study of a single body magnet, low electron energy storage ring, performed with the Finite Element (FE) and Finite Difference Time-Domain (FDTD) modeling possibilities in the CST Studio Suite 2010 software package. Insights were obtained for the most crucial components: the magnet yoke, the internal RF cavity and the resonance injection component. Finally, the model of the storage ring was verified using the particle tracker solver which tracks the injected electrons along the ring.

 
THP097 Development of a Thermionic Electron Gun of the L-band Linac for FEL Operation gun, FEL, linac, cathode 965
 
  • N. Sugimoto, G. Isoyama, R. Kato, S. Suemine, A. Tokuchi
    ISIR, Osaka
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai
 
 

We are conducting FEL experiments with the L band electron linac at Osaka University. The linac is equipped with a thermionic electron gun and the three-stage sub-harmonic buncher(SHB) system. In FEL experiments an 8μs long electron pulse is injected from the gun and the SHB system is turned on for generating a multi-bunch electron beam of an 8μs duration with 2nC charge per bunch and 9.2 ns intervals between bunches. It repeatedly amplifies light pulses stored in the optical resonator of the FEL. The roundtrip time of the light pulses is 37 ns, so that four light pulses are stored in the resonator. The FEL gain becomes higher at least in proportion to the peak current in the bunch or charge per bunch. The present charge value is limited by the high beam loading in the acceleration tube of the linac, exceeding a half of the input RF power. If the bunch intervals can be extended to 37 ns, the charge per punch can be made four times higher for the same beam loading, resulting in significant increase of the FEL gain. To generate such an electron beam, we are developing the electron gun system with a high-repetition-rate grid-pulser. We will report the outline of the study.

 
THP101 Femtosecond Electron Bunch Generation using Photocathode RF Gun emittance, laser, gun, linac 968
 
  • K. Kan, T. Kondoh, T. Kozawa, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
    ISIR, Osaka
 
 

Femtosecond electron beam, which is essential for pump-probe measurement, was generated with a 1.6-cell S-band photocathode rf gun. The rf gun was driven by femtosecond UV laser pulse (266 nm), which was generated with third-harmonic-generation (THG) of Ti:Sapphire femtosecond laser (800 nm). The longitudinal and transverse dynamics of the electron bunch generated by the UV laser was investigated. The bunch length was measured with the dependence of energy spread on acceleration phase in a linac, which was set at the downstream of the rf gun. Transverse emittance at the linac exit was also measured with Q-scan method.

 
THP102 Photocathode Femtosecond Electron Linac and Its Applications gun, laser, linac, emittance 971
 
  • J. Yang, K. Kan, T. Kondoh, N. Naruse, Y. Nurooka, K. Tanimura, Y. Yoshida
    ISIR, Osaka
  • J. Urakawa
    KEK, Ibaraki
 
 

Photocathode rf electron linac facilities have been developed in Osaka University to reveal the hidden dynamics of intricate molecular and atomic processes in materials. One of the linacs was developed using a booster linear accelerator and a magnetic bunch compressor. This linac was successfully produced a 100-fs high-brightness electron single bunch and initiated the first experimental study of radiation chemistry in the femtosecond time region. Another was constructed with a photocathode rf gun to generate a near-relativistic 100-fs electron beam with a beam energy of 1~4 MeV. A time-resolved MeV electron diffraction was successfully developed with this gun to study the ultrafast dynamics of structure change in materials.

 
THP106 Design of a 10 fs Electron Beam with a Photocathode RF Gun and an RF Buncher gun, cathode, solenoid, target 980
 
  • J.H. Han
    Diamond, Oxfordshire
 
 

Ultrashort electron beams can be used for investigating ultrafast dynamics of physical, chemical or biological systems. With an S-band photocathode gun, simulations have been done in order to generate ultrashort electron beams. Optimizations to generate ultrashort electron beams with a small beam divergence and to minimize the system sensitivity against RF jitter are reported.

 
THP108 Pulsed Laser Heating of Thermionic Cathodes in RF Guns cathode, laser, gun, simulation 986
 
  • M. Borland, B. Brajuskovic, R.R. Lindberg, N. Sereno
    ANL, Argonne
 
 

The proposed injector design for the X-ray Free Electron Laser Oscillator* uses a 100 MHz thermionic rf gun in order to obtain beams with very small emittances at high repetition rates**. The required beam rate is only 1 to 10 MHz, so 90 to 99\% of the beam must be dumped. In addition, back-bombardment of the cathode is a significant concern. To address these issues, we propose using a laser to quickly heat the surface of a cathode in order to achieve gated thermionic emission in an rf gun. This may be preferrable to a photocathode in some cases owing to the robustness of thermionic cathodes and the ability to use a relatively simple laser system. We present calculations of this process using analysis and simulation. We also discuss potential pitfalls such as cathode damage.


*K. J. Kim et al., Phys. Rev. Lett. 100, 244802 (2008).
**P. N. Ostroumov et al., Proc. Linac08, 676-678.

 
THP109 Potential for an Ultra-low Emittance Thermionic Triode Gun gun, cathode, emittance, space-charge 989
 
  • X.W. Dong, M. Borland, G. Decker, K.-J. Kim, J.G. Power, N. Sereno
    ANL, Argonne
 
 

The proposed X-ray Free Electron Laser Oscillator* requires an ultra-low emittance gun that generates continuous electron bunches at 1 to 10 MHz. Recently, T. Shintake raised the possibility of using a pulsed triode gun with a thermionic cathode. In this paper, we investigate the feasibility for such a gun as part of an injector producing normalized emittances in the 0.1 μm range with 2 ps rms duration for 50 pC/bunch. We also explore some implementation concepts.


*K. J. Kim et al., Phys. Rev. Lett. 100, 244802 (2008)

 
THP111 Development of a 500-kV Photo-Cathode DC Gun for ERL Light Sources cathode, gun, high-voltage, radiation 995
 
  • N. Nishimori
    JAEA, Ibaraki-ken
  • R. Hajima, R. Nagai
    JAEA/ERL, Ibaraki
  • Y. Honda, T. Miyajima, M. Yamamoto
    KEK, Ibaraki
  • H. Iijima, M. Kuriki
    HU/AdSM, Higashi-Hiroshima
  • M. Kuwahara, T. Nakanishi, S. Okumi
    Nagoya University, Nagoya
  • T. Muto
    Tohoku University, School of Scinece, Sendai
 
 

An electron gun capable of delivering high current and high brightness electron beam is indispensable for next generation energy recovery linac light sources. A high voltage photocathode DC gun is a promising gun for such new light sources. It is however difficult to apply DC high voltage on a ceramic insulator with a rod supporting cathode electrode because of field emission from the rod. In order to mitigate the problem, we have employed a segmented insulator with rings which guard the ceramics from the field emission and recently succeeded in applying 500-kV on the ceramics for eight hours without any discharge. This high voltage testing was performed with a simple configuration without NEG pumps and electrodes. The next step is to repeat the same high voltage testing with a full configuration necessary for beam generation. We have designed electrodes for the maximum surface electric field not to exceed 11 MV/m at 500 kV while keeping the distance between the electrodes 100 mm. NEG pumps with a pumping speed of 7200 L/s have been installed in the gun chamber. A photocathode preparation system was connected to the gun chamber and beam generation is planned this summer.

 
THP117 Study of the Frequency Tuning Effect for the Improvement of Beam Brightness in ECR Ion Sources plasma, ion, ECR, resonance 1013
 
  • S. Gammino, L. Celona, G. Ciavola, D. Mascali, R. Miracoli
    INFN/LNS, Catania
  • F. Maimone
    GSI, Darmstadt
 
 

According to the model that has driven the development of ECRIS in the last years, a large variation of the pumping microwave frequency (order of GHz) boosts the extracted current for each charge state because of a larger plasma density. Recent experiments have demonstrated that even slight frequency's changes (of the order of MHz) considerably influence the output current, and also the beam properties after the extraction (beam shape, brightness and emittance). In order to investigate how this fine tuning affects the plasma heating, a set-up for the injection of different microwave frequencies into the ECRIS cavity has been prepared. The microwave power is fed by means of a Travelling Wave Tube amplifier with a broad operating frequency range. The frequency can be systematically changed and the beam output is recorded either in terms of charge state distributions and beam emittance. The detected brehmsstralung X-rays are additionally analysed: they give insights about the electron energy distribution function (EEDF). The results are compared with simulations and data coming from previous preliminary experiments.

 
THP121 Development of an L-band RF Gun for High-duty-cycle Operation cavity, gun, resonance, vacuum 1025
 
  • G. Isoyama, R. Kato, N. Sugimoto
    ISIR, Osaka
  • H. Hayano, H. Sugiyama, T. Takatomi, J. Urakawa
    KEK, Ibaraki
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima
 
 

We are developing an L-band photocathode RF gun in collaboration with KEK and Hiroshima University. The RF gun will be used not only at Osaka University but also at STF of KEK, so that it can be stably operated at the input RF power of 5 MW with 1 ms duration and a 5 Hz repetition rate, resulting in the average input power of 25 kW. The water-cooling system of the 1.5 cell cavity is designed, which can take the heat with the temperature rise of the cavity body by 5°C at the flow rate of cooling water of 358~723 liter/min. The several parts of the RF cavity are assembled with brazing and the most crucial process is brazing of three main components of the RF cavity into one. The brazing has to be tight and perfect not to allow vacuum leak, while the brazing filler metal must not go out on to the inner surface of the cavity to avoid discharge triggered by the scabrous filler metal on the cavity wall. Test experiments are conducted and a guideline is concluded for such brazing.

 
FR103 Commissioning of the EBIS-Based Heavy Ion Preinjector at Brookhaven ion, rfq, linac, booster 1033
 
  • J.G. Alessi, E.N. Beebe, S. Binello, L.T. Hoff, K. Kondo, R.F. Lambiase, V. LoDestro, M. Mapes, A. McNerney, J. Morris, M. Okamura, A.I. Pikin, D. Raparia, J. Ritter, L. Smart, L. Snydstrup, M. Wilinski, A. Zaltsman
    BNL, Upton, Long Island, New York
  • T. Kanesue
    Kyushu University, Hakozaki
  • U. Ratzinger, A. Schempp
    IAP, Frankfurt am Main
 
 

This talk will present commissioning of a new heavy ion pre-injector at Brookhaven National Laboratory. This preinjector uses an Electron Beam Ion Source (EBIS), and an RFQ and IH Linac, both operating at 100.625 MHz, to produce 2 MeV/u ions of any species for use, after further acceleration, at the Relativistic Heavy Ion Collider, and the NASA Space Radiation Laboratory. Among the increased capabilities provided by this preinjector are the ability to produce ions of any species, and the ability to switch between multiple species in 1 second, to simultaneously meet the needs of both physics programs.

 

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FR105 Study of Basic Breakdown Phenomena in High Gradient Vacuum Structures cavity, accelerating-gradient, vacuum, collider 1043
 
  • V.A. Dolgashev
    SLAC, Menlo Park, California
 
 

We present the results of R&D aimed at exploring the basic physics of RF breakdown phenomena in high vacuum structures. We performed an extensive experimental survey of materials for RF magnetic field induced metal fatigue. To do this, we designed a cavity operating at a TE01m-like mode which focuses RF magnetic field on the flat sample surface. We tested more than 20 samples of materials including single crystal copper, copper alloys, and refractory metals. With these results in hand, we constructed standing wave cavities of different geometries and materials to conduct RF-breakdown experiments. To study a broad range of materials and surfaces, we explored different structure-joining techniques, including those which allow us to avoid high temperature brazing. Using structures of different geometries, we examined the effect of the mixture of surface electric and magnetic fields on breakdown behavior. To study this effect further we designed a structure in which we can adjust the mixture of fields using two independent RF sources.

 

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FR202 Muon Colliders and Neutrino Factories collider, factory, cavity, acceleration 1048
 
  • S. Geer
    Fermilab, Batavia
 
 

Over the last decade there has been significant progress in developing the concepts and technologies needed to produce, capture and accelerate O(1021) muons/year. This development prepares the way for a new type of neutrino source (Neutrino Factory) and a new type of very high energy lepton-antilepton collider (Muon Collider). A review is given of the motivation, design and R&D for Neutrino Factories and Muon Colliders.

 

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