Paper | Title | Other Keywords | Page |
---|---|---|---|
MOP063 | High-Power Lithium Target for Accelerator-Based BNCT | target, linac, neutron, electron | 223 |
|
|||
A 50 kW, water-cooled conical target for producing neutrons via the Li-7(p,n)Be-7 reaction at 2.5 MeV proton energy is under development at Linac Systems. This target is intended to accept a stationary, expanded CW beam with a diameter of 8 cm directly from an rf linac, resulting in peak surface heat flux of 7.5 MW m-2 (a 'waterbag' beam power distribution is assumed). The target is predicted to meet the intensity requirements for practical accelerator-based boron neutron capture therapy (BNCT), in concert with Linac Systems' CW RFI linac. Lithium metal targets present well-known physical and mechanical challenges at high beam power density that are addressed in our design. For instance, lithium melts at 180 C, necessitating efficient removal of heat at a low ΔT relative to ambient temperature. CFD modeling indicates that with 50 kW incident beam power, the peak lithium temperature can be held below 150 C with a water flow rate near 80 l min-1 and corresponding pressure drop of 170 kPa. The target prototype has been fabricated and is undergoing experimental thermal-hydraulic testing using an electron beam at the Plasma Materials Test Facility, Sandia National Laboratory. |
|||
MOP067 | High Gradient Excitation and RF Power Generation Using Dielectric Loaded Wakefield Structures | electron, wakefield, klystron, laser | 232 |
|
|||
Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. |
|||
MOP074 | Beam Dynamics Simulations of Sub-ps Electron Bunch Produced in a Photo-Injector | emittance, simulation, electron, laser | 248 |
|
|||
A growing number of experiments require low emittance ultra-short electron bunches in the 100 fs range (rms value) for the production of coherent light or the injection in plasma for laser-plasma acceleration. Especially in the last case it is highly desirable to have a compact accelerator; hence a strong experimental activity is carried out to get such a beam directly from a photo-injector. We have performed beam dynamic simulations using the PARMELA code to study the performances of the alphaX photo-injector installed in the University of Strathclyde in UK. This rf gun is aimed to produce electron bunches of 100 pC bunch charge, 100 fs bunch length and 1 mmmrad transverse emittance. We will show the results of systematic parametric studies as a function of charge and laser pulse duration as well as the natural evolution of the beam phase space as a function of the distance from the photo-cathode. |
|||
MOP104 | Parallel 3D Finite Element Particle-In-Cell Code for High-Fidelity RF Gun Simulations | simulation, wakefield, space-charge, emittance | 317 |
|
|||
Funding: Work supported by DOE contract DE-AC02-76SF00515. |
|||
TU204 | Design and Performance of L-Band and S-Band Multi-Beam Klystrons | cathode, cavity, klystron, bunching | 369 |
|
|||
In the last couple of years, great achievements have been realized through world-wide developments of multi-beam klystrons (MBK) in the L-band and S-band. These MBKs are developed by industries such as Toshiba, Thales and CPI for the European X-FEL project or at the Naval Research Lab or by the Chinese Academy of Sciences for high-power, low-voltage radar systems. Some of them are already in operation at full specifications and are commercially available. The MBKs are superior to conventional single-beam klystrons through their ability to increase the output power dramatically while the operating voltage can be kept at a similar level. This talk will review the performances of these multi-beam klystrons, their design features, and future development plans. |
|||
|
|||
TUP005 | The New Single Bunch Injector for ELSA | cathode, linac, single-bunch, solenoid | 392 |
|
|||
Since 1966 a Varian factored injector is in use at the accelerator complex of the University of Bonn serving several experiments to investigate the subnuclear structure of matter. This injector will have to be replaced for several reasons. The new injector will operate in a single bunch mode of 2 A beam current and is currently under construction. Also a 2 μs long pulse mode of 500 mA beam current will be available for ordinary accelerator operation for hadron physics experiments. Produced by a pulsed thermionic 90 kV gun, compression of the pulses is achieved by a 500 MHz prebuncher as well as one β-matching travelling wave buncher running at the linac frequency of 3 GHz. The injector has been designed and optimised using the software package EGUN and numerical simulations based on the paraxial differential equations. The single bunch mode will allow to investigate single bunch instabilities within the Helmholtz alliance "Physics at the Terascale". |
|||
TUP008 | Recent Changes to the e- / e+ Injector (Linac II) at DESY | linac, target, positron, electron | 401 |
|
|||
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. The Particle Intensity Accumulator (PIA) is also considered part of the injector complex accumulating and damping the 50 Hz beam pulses from the linac and transferring them with a rate of 6.25 Hz or 3.125 Hz into the Synchrotron DESY II. The typical positrons rates are 6·1010/s. DESY II and Linac II will serve as injectors for the two synchrotron light facilities PETRA III and DORIS. Since PETRA III will operate in top-up mode, Linac availability of 98-99% are required. DORIS requires positrons for operation. Therefore during top-up mode positrons are required for both rings. In order to maintain its reliability over the operation time of the new facility PETRA III, the major components of the linac were renovated. Some components were redesigned taking into account experience from 30 years of operation. |
|||
TUP028 | Status of High Current R&D Energy Recovery Linac at Brookhaven National Laboratory | electron, cavity, emittance, SRF | 453 |
|
|||
Funding: Work performed under contract No. DE-AC02-98CH10886 with the auspices of the DoE of United States. |
|||
TUP029 | Electron Linac Based Coherent Radiation Light Source Project at OPU | radiation, electron, linac, synchrotron | 456 |
|
|||
The coherent synchrotron and transition radiation from electron bunches of a linear accelerator (linac) has continuous spectra in a submillimeter to millimeter wavelength range at relatively high peak-intensities. This light source has been applied to absorption spectroscopy by the authors for various kinds of matters with relatively strong light absorbance such as water and aqueous solutions. The other important characteristics of the coherent radiation are picosecond pulsed light and the high peak intensity of the electric field which can be introduced into matters. In our new project the light source using the pulsed coherent synchrotron and transition radiation will be developed by using the electron beams of a 18 MeV S-band electron linac at Osaka Prefecture University (OPU). The pulse shape of the radiation has been evaluated from the shape of the electron bunch. The system of the light source has been optimized and is under construction. The light source will be applied to the pulsed excitation of matters and to the pump-probe experiment using the electron beam and the coherent radiation. |
|||
TUP035 | New Experimental Results from PITZ | emittance, cathode, cavity, laser | 474 |
|
|||
Funding: This work was partly supported by the European Community, contracts RII3-CT-2004-506008 and 011935, and by the 'Impuls- und Vernetzungsfonds' of the Helmholtz Association, contract number VH-FZ-005. * L. Staykov et al., "Measurements of the Projected Normalized Transverse Emittance at PITZ", Proceedings of the FEL 2007, Novosibirsk, Russia, August 2007. |
|||
|
|||
TUP038 | MIR-FEL with 4.5-Cell Thermionic RF-Gun | FEL, electron, undulator, klystron | 477 |
|
|||
An MIR-FEL facility, Kyoto University FEL (KU-FEL), has been developed for applications in "sustainable energy science", such as fundamental studies on high-efficiency solar cells. The KU-FEL, consisting of an S-band thermionic rf gun, a 3 m accelerator tube and a planer undulator, aims to generate 4-13 μmeter tunable FEL. The first lasing was achieved on March, 2008 at 12.4 μmeters by using a beamloading compensation method both in the rf gun and in the accelerator tube. *Furthermore, we introduced detuning to the rf gun and succeeded to generate an electron beam with macropulse duration of 5.1 μseconds, average current of 100 mA and energy spread of 0.5% which led to power saturation in FEL. In the conference, the improvements of the electron beam properties and power saturation of the KU-FEL will be discussed. *H. Ohgaki et al., 'First Lasing at 12 um Mid Infrared Free Electron Laser at Kyoto University', Japanese Journal of Applied Physics, accepted for publication. (2008). |
|||
TUP039 | Status of the LINAC-800 Construction at JINR | electron, linac, acceleration, FEL | 480 |
|
|||
800 MeV electron linac (LINAC-800) is under construction at JINR. It will be used as a driver for Volume FEL and as a test bench for commissioning of elements of the ILC. Presently the electron injector is commissioned and the electron beam of 50 keV of the energy at current of about 15 mA was obtained. The results of the injector operation at nominal parameters (400 keV, 300 mA) and commissioning of the first accelerating section at 20 MeV are discussed. |
|||
TUP040 | Linear Accelerator for the PSI-XFEL FEL3 Beamline | linac, FEL, emittance, laser | 483 |
|
|||
In the planned PSI-XFEL facility, three FEL branches will supply coherent, ultra-bright, and ultra-short XFEL photons at wide wavelength range. FEL branch 1 will use a 6.0 GeV driving linac to generate hard X-rays from 0.1 nm to 0.3 nm, while FEL branch 2 is foreseen for X-rays from 0.3 nm to 1.0 nm. However, FEL branch 3 was designed to supply spatially as well as temporally coherent soft X-rays from 1.0 nm to 10 nm with the High-order Harmonic Generation based seeded HGHG scheme. To reach emittances of 0.2 mm.mrad and to squeeze consequently the whole facility within an 800 m long tunnel, PSI is presently developing an advanced low emittance gun (LEG) based on a 1 MV high gradient pulsed diode and field emission. The advanced LEG will be used to drive FEL branch 1 and 2, while an RF photoinjector will be used to drive the FEL branch 3. In this paper, we describe a CTF3 RF gun based injector, two bunch compressors, two diagnostic sections, and linacs for the PSI-XFEL FEL branch 3. |
|||
TUP042 | High Repetition Rate Electron Injectors for FEL Based Next Generation Light Sources | emittance, cavity, SRF, simulation | 489 |
|
|||
Several laboratories concentrate their efforts on development of high repetition rate FEL based next generation light sources. One particular concept under development at STFC Daresbury Laboratory specifies high brightness electron bunches with a charge of 0.2-1 nC which arrive with a frequency up to 1 MHz. As emittance of the bunches should not exceed 1 um, traditional high repetition rate thermionic injectors, similar to the ones used at high micropulse repetition rate FELs like ELBE or FELIX, may not be used. We consider three options of high repetition rate injectors based on photocathode guns - a high voltage dc gun, a one and half cell superconducting rf gun and a normal conducting VHF gun, recently proposed at LBNL. We consider practical injector schemes for all three guns and provide the results of beam dynamic simulations. We also discuss the photocathodes which may be used in each gun, as this critical component defines achievable beam parameters and operational efficiency of the injectors. |
|||
TUP044 | The NPS-FEL Injector Upgrade | cathode, laser, injection, FEL | 495 |
|
|||
Funding: This research is supported by the Office of Naval Research and the Joint Technology Office. |
|||
TUP066 | Commissioning of 10-MeV L-band Electron Linac for Industrial Applications | electron, klystron, linac, high-voltage | 548 |
|
|||
Funding: This work is supported by KAPRA and POSTECH Physics BK21 Program. |
|||
TUP087 | Spectral and Charge-Dependence Aspects of Enhanced OTR Signals from a Compressed Electron Beam | linac, optics, radiation, cathode | 603 |
|
|||
Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 |
|||
TUP094 | Development of a Photocathode RF Gun for an L-Band Electron Linac | cavity, electron, cathode, emittance | 621 |
|
|||
Funding: This research is partly supported by the accelerator support program to universities conducted by the High Energy Accelerator Research Organization in Japan. |
|||
TUP095 | Development of a Cs-Te Cathode RF Gun at Waseda University | cavity, electron, cathode, resonance | 624 |
|
|||
Funding: Work supported by MEXT High Tech Research Project HRC707, JSPS Grant-in-Aid for Scientific Research (B)(2) 16340079 |
|||
TUP096 | RF Gun Development with Improved Parameters | cavity, simulation, cathode, vacuum | 627 |
|
|||
During development and operation of DESY L-band rf gun cavities, desires for further improvements were formulated. The next step of development is based on the proven advantages of existing cavities, but includes significant changes. The L-band 1.6 cell rf gun cavity is intended for operation in pulse mode with electric fields at the cathode of up to 60 MV/m, rf pulse length of ~1 ms and average rf power higher than existing gun cavities. In the new design the cell shape is optimized to have the maximal surface electric field at the cathode and lower rf loss power. The cavity cells are equipped with rf probes. Cooling circuits are designed to combine cooling efficiency with operational flexibility. In the report, the main design ideas and simulation results are described. |
|||
TUP099 | Design and Optimization of an S-Band Photoinjector | emittance, cavity, solenoid, laser | 636 |
|
|||
Many X-ray Free Electron Laser (XFEL) projects are under construction or are being proposed. A photoinjector with low transverse emittance is one of the key elements for successful XFEL operation. For the last two decades, photoinjectors have been developed to reach the XFEL requirement, typically with a normalised emittance of 1 mm mrad for a 1 nC bunch and high peak current. Here, we make a further numerical optimization of an S-band photoinjector to achieve 0.5 mm mrad for 1 nC bunch in a structure that should permit high repetition rates to be achieved. Optimizations for alternative operation conditions with lower charge and lower emittance are also shown. |
|||
TUP100 | The Optimization of a DC Injector for the Energy Recovery Linac Upgrade to APS | emittance, laser, linac, electron | 639 |
|
|||
Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. |
|||
TUP101 | Photocathode R&D Program at LBNL | electron, photon, emittance, cathode | 642 |
|
|||
Funding: US Deparment of Energy |
|||
TUP106 | Simulation of Field-Emission Cathodes for High Current Electron Injectors | cathode, electron, simulation, FEL | 652 |
|
|||
Funding: Work supported by the Department of Defense under contract N00014-06-1-0587 with Northern Illinois University |
|||
TUP110 | Modeling of a Low Frequency SRF Electron Gun for the Wisconsin FEL | emittance, cavity, cathode, FEL | 658 |
|
|||
Funding: This work is supported by the University of Wisconsin-Madison and MIT, and by the US NSF under award No. DMR-0537588 * O.J. Luiten, et al., Phys. Rev. Lett., 93, 094802-1 (2004) |
|||
TUP111 | Longitudinal Bunch Lengthening Compensation in a High Charge RF Photoinjector | emittance, booster, electron, solenoid | 661 |
|
|||
Funding: Work supported by DOE contract DE-AC02-76SF00515 |
|||
TUP117 | Development of Ultra-Low Emittance Injector for Future X-Ray FEL Oscillator | emittance, linac, electron, cavity | 676 |
|
|||
Funding: This work was supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC-02-06CH11357. *K.-J. Kim, Y. Shvyd'ko, and S. Reiche, to be published in Physical Review Letters (2008) |
|||
WE103 | First Results from the ERL Prototype (ALICE) at Daresbury | linac, cavity, vacuum, cathode | 694 |
|
|||
The energy recovery linac prototype at Daresbury is now called ALICE (Accelerators and Lasers In Combined Experiments). This paper presents the results obtained in the past year, including the second (fourth) period of gun commissioning. Following the completion of gun commissioning in November 2007, the dedicated gun diagnostic line was removed and the electron gun attached to the booster cavity and hence the rest of the machine. The paper outlines some of the challenges experienced during the commissioning of both the photoinjector system and the superconducting cavities and presents the current status of the project as well as the very latest results from commissioning during the summer of 2008. |
|||
|
|||
WE104 | First Tests of the Cornell University ERL Injector | cavity, laser, emittance, cathode | 699 |
|
|||
Funding: Work supported by the National Science Foundation under contract PHY 0131508 |
|||
|
|||
THP013 | Various Applications of Dry-Ice Cleaning in the Field of Accelerator Components at DESY | cavity, cathode, SRF, superconductivity | 803 |
|
|||
Funding: We acknowledge the support of the European Community Research Infrastructure Activity under FP6 'Structuring the European Research Area' program (CARE, contract number RII-CT-2003-506395 |
|||
THP052 | Development of a High-Pressure Chemical Etching Method as a Surface Treatment for High-Field Accelerating Structures Made of Copper | cathode, cavity, acceleration, RF-structure | 903 |
|
|||
The acceleration gradient is limited by breakdown in an accelerating rf structure, including its surface condition of the inner wall. The surface treatment is an important technique to achieve the maximal acceleration gradient of an accelerating structure. We chose chemical etching as a method of surface treatment for accelerating rf structures made of copper. To study rf breakdown and effect of surface treatments, we used a pillbox-type single cell rf gun cavity. The highest cathode surface field (190 MV/m) of rf gun cavity was accomplished with this surface treatment under rf-conditioning elapsed time (21 days) in 2004. SPring-8 rf gun has been operating with the highest gradient in the world. This indicates that our treatment is considerably effective to improve the inner cavity surface made of copper. Further, we developed the high-pressure chemical etching for more complicated inner structures in 2006. Using a cartridge-type photocathode rf gun, high-field experiments were performed with cathode plugs chemical etching treated under deferent pressure condition. We report these results on highest gradient, using test copper samples treated with high-pressure chemical etching. |
|||
THP079 | Operation Experience with the FLASH RF Waveguide Distribution System at DESY | cavity, klystron, superconducting-cavity, cryogenics | 978 |
|
|||
The rf stations for the FLASH linear accelerator at DESY provide rf power up to more than 5 MW, 1.3 ms and 10 Hz at 1.3 GHz for forty-eight superconducting cavities grouped into six cryogenic modules and for one normal conducting rf gun. A WR650 waveguide distribution system distributes the power generated by five active rf stations using 5 MW single beam and a 10 MW multibeam klystron to the cavities and the gun. Since FLASH is based on the Tesla Test Facility, TTF, a number of different distribution layouts for the different modules and the gun have been developed and used over the years in terms of type of components and distribution scheme. This paper presents the layout and summarizes the experience with the existing waveguide distribution system. |
|||
|
|||
FR103 | Operation of FLASH as an FEL User Facility | FEL, electron, radiation, photon | 1100 |
|
|||
FLASH, the FEL user facility at DESY, is operated with an electron beam energy up to 1 GeV corresponding to a photon wavelength down to 6.5 nm. The full year 2008 is dedicated to beam operation: about half of the time is scheduled for FEL users, and the rest for accelerator and FEL physics studies. Operational experience gathered at FLASH is very important not only for further improvements of the FLASH facility itself, but also for the European XFEL and for the ILC R&D effort. This talk reports our experience operating FLASH as a user facility. Failure statistics are included as well. |
|||
|
|||
FR104 | Review of Advanced Laser Technologies for Photocathode High-Brightness Guns | laser, polarization, electron, cathode | 1105 |
|
|||
I developed a 3-D pulse shaping system in UV as an ideal laser for yearlong stable photoinjector. At SPring-8, the laser's pulse-energy stability has been improved to 0.7~1.4% at the UV (263 nm) under the laser environmental control included humidity. In addition, the ideal spatial and temporal profiles of an UV-laser pulse are essential to suppress emittance growth in an rf gun. I apply a deformable mirror that automatically shapes the spatial profile with a feedback routine, based on a genetic algorithm, and a pulse stacking system consisting of three birefringence Alpha-BBO crystal rods for temporal shaping at the same time. The 3D shape of the laser pulse is spatially top-hat (flattop) and temporally a square stacked chirped pulse. Using a 3D-shaped laser pulse with diameter of 0.8 mm on the cathode and pulse duration of 10 ps (FWHM), we obtain a normalized emittance of 1.4 pi mm mrad with a beam energy of 26 MeV. To keep the mirror away from beam axis, I developed a new hollow laser incidence with an axicon final focusing. Furthermore, I am developing a laser-induced Schottky-effect-gated photocathode gun using Z-polarization of the laser source with the hollow incidence. |
|||
|