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MOYMA01 | Overview of Energy-Recovery Linacs | electron, linac, emittance, radiation | 11 | ||||
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An energy-recovery linac (ERL) is capable of generating an electron beam of high-brightness and high average current. It is, thus, a promising device for future light sources such as next-generation X-ray sources and high-power FELs, and several projects are under way in the world. In this talk, we overview the current status of these projects. Recent studies on beam dynamics issues and development of key components for the ERLs are also presented.
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TUPMA031 | Development of Trigger and Clock Delay Module with Ultra-wide Range and High Precision | controls, synchrotron, electron, insertion | 145 | ||||
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Pump and probe experiments using pulse lasers and synchrotron radiation require precise timing relation between the laser pulse and the RF signal of the accelerator. The pulse laser needs clock signal for a mode-locked oscillator and trigger signal to a regenerative oscillator. The delay time of these two signals were usually adjusted by using a mechanical phase shifter or a cable delay. They have disadvantages of short tuning range or discontinuity in the clock signal. We developed a new delay module, which can continuously change the delay time with the range of ±1 s and the precision better than 5 ps. The key point of the module is combination of an IQ modulator and a synchronous counter. The IQ modulator can change the phase of the RF signal with infinite amount with high precision in both plus and minus direction, which is used to produce the laser clock. The phase-modulated RF signal is also fed to the synchronous counter and its output is used to the trigger of the regenerative oscillator. The effectiveness of this module was confirmed by an experiment carried out at the SPring-8. Detail composition of the module, its application and performance are described in the paper.
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TUPMA039 | Comparison of Codes for Smith-Purcell FEL | simulation, electron, free-electron-laser, plasma | 166 | ||||
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Smith-Purcell FELs using low energy electron beam are being seen as attractive option for a compact source of coherent Terahertz ratiation. Recently, Kumar and Kim [1] have performed numerical simulation of Smith-Purcell free-electron lasers (SP-FELs) based on a computer code using Maxwell-Lorent equations. Li et al. [2], and Dounhue et al. [3] have performed calculations using PIC codes. In this paper, we present a comparision of these methods and compare results obtained using different codes.
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1. V. Kumar et al., Phys. Rev. E 73, 026501 (2006). 2. D. Li et al., Phys. Rev. ST Accel. Beams 9, 040701 (2006). 3. J. T. Donohue et al., Phys. Rev. ST Accel. Beams 9, 060701 (2006). |
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TUPMA047 | Development of a Photocathode DC Gun at JAEA-ERL | gun, electron, emittance, cathode | 175 | ||||
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An electron gun producing an e-beam with high-brightness and high average-current is a key component to realize a next-generation X-ray light source based on energy-recovery linac (ERL). In JAEA, we are developing a photocathode DC gun for a future ERL light source. The DC gun is operated at 250 kV and 50 mA at maximum, and equipped with a load-lock chamber for cathode preparation. In order to keep small emittance at high current operation, we adopt superlattice semiconductor as a photocathode. In this paper, we present the status of the gun development and future plans towards the ERL test facility to construct in collaboration with KEK.
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TUPMA067 | New Timing System for the L-band Linear Accelerator at Osaka University | linac, gun, single-bunch, electron | 208 | ||||
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A highly precise and flexible timing system has been developed for the L-band linac at ISIR, Osaka University. It provides four RF signals and several timing signals for operation of the linac and for experiments with the linac. In order to realize long-term stability of the timing system and hence operation of the linac, a rubidium atomic clock producing a 10 MHz RF signal with the fractional stability of 10-15 is used as a time base for a synthesizer used as a master oscillator for generating the acceleration frequency of 1.3 GHz. The 1.3 GHz signal from the master oscillator is directly counted to produce the four RF signals and the clock signal of the timing system at 27 MHz. The master timing signals for linac operation is taken from the AC line frequency and it is synchronized with the 27MHz clock signal precisely. To make an arbitrary delayed timing signal, a standard digital delay generator is used to make a gate signal for a GaAs RF switch, with which one of the 27MHz clock pulses is sliced out to generate the delay timing signal. Any timing signal can be made in an interval of 37 ns and the timing jitter of the delayed signal is achieved to be as short as 2 ps.
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TUPMA083 | High Quantum Efficiency Photocathode for RF Guns | cathode, gun, space-charge, electron | 223 | ||||
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High Quantum Efficiency Photocathodes are nowadays routinely used as electron sources for laser driven RF guns. In this paper, we review the production, characterization and operation performances of the Cs2Te photocathodes prepared at INFN Milano LASA and operated at DESY for the FLASH and the PITZ photoinjectors.
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TUPMA123 | Electron Acceleration in the Wake Field Excited by 200TW Femto Second Laser in Underdense Plasma | electron, plasma, scattering, acceleration | 277 | ||||
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Laser-plasama acceleration experiment has been carried out using 200TW, 30fs Ti:Sapphire laser pulses focused on helium gas-jets with F/8.75 optics. Intense mono-energetic electron beams have been produced by controlling plasma length and density precisely. Energy spectral oscillations in respect to ejection angle have been also observed. Measurements of images from Thomson scattering and fluorescence side scattering from plasma indicate highly relativistic effects such as a long self-channeling, hosing instability and filamentation. It seems that these nonlinear phenomena strongly disturb high energy gain acceleration and high quality beam generation.
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WEZH102 | Beam Instrumentation Experience at ATF | extraction, emittance, radiation, electron | 305 | ||||
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Accelerator Test Facility (ATF) at KEK is a test accelerator for linear collider development. It produces a stable low emittance beam that satisfies the requirements in the ILC. Various beam instrumentations (cavity BPM, laser wire, fast feedback, XSR, ODR etc.) have been tested. This presentation will review our recent experiences.
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WEPMA111 | Mechanical Engineering Challenges in the Development of the FEL at RRCAT | undulator, vacuum, linac, gun | 479 | ||||
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The Compact Ultrafast TErahertz Free-Electron Laser (CUTE-FEL) is being developed by BP&FEL Laboratory, RRCAT, which is designed to lase around 80 mm. Sub-systems like S-band high gradient accelerating structures, pre-buncher, buncher, pure permanent undulator etc. have already been developed and others are in advanced stage of fabrication/commissioning. In this paper we present the design, fabrication, measurements and status of various prototype developments of structures.
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WEPMA112 | Thermal Simulations of a Photocathode R. F. Gun | gun, simulation, vacuum, electron | 482 | ||||
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We are developing a photocathode linac, which uses a 2856 MHz r.f. gun, with a copper cathode driven by a 102 MHz, 266 nm laser at inclined incidence. The laser photocathode r.f. gun is a 1.6 cell BNL/SLAC/UCLA type III r.f. gun. In this paper we present the dynamic thermal cooling simulations to calculate the structural deformations and consequent frequency drift of the gun. We have done a complete r.f.-thermal-structural-r.f finite-element analysis (FEA) of the gun in that order, using ANSYS/MULTIPHYSICS. We find that with the present coolant channel design the gun can operate at up to 2 Hz without any significant change in resonant frequency and field balance.
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THC3MA04 | Status of the Novosibirsk High Power Terahertz FEL | radiation, electron, undulator, vacuum | 616 | ||||
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The first stage of Novosibirsk high-power free-electron laser (FEL) was commissioned in 2003. It is based on the normal conducting CW energy recovery linac. Now the FEL provides electromagnetic radiation in the wavelength range 120180 micrometers. The average power is 400 W. The minimum measured line width is 0.3%, which is close to the Fourier-transform limit. The assembly of user beamline is in progress, parts of the full-scale machine are manufactured. The latter will operate in the near IR region and will provide higher average power.
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THPMA005 | SCSS RF Control Toward 5712 MHz Phase Accuracy of One Degree | controls, klystron, electron, acceleration | 634 | ||||
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To check the feasibility of X-FEL(SCSS), the 250 MeV prototype accelerator was constructed at SPring-8. The low level RF control system with a 5712 MHz pulsed RF signal was built to achieve very-tight requirements that were phase stability and resolution of less than 1 deg.. These requirements correspond to a beam energy variation of 10-4 at the crest acceleration and time stability and resolution of less than 500 fs. To realize the requirements, IQ modulators/detectors, arbitrary wave form generators/detectors of VME modules to handle an IQ function were developed. The PID control and the adaptive control method, which the modules can manipulate, were employed to obtain the requirements. We finally achieved the phase setting and detecting resolution of the IQ detectors/modulators of ± 0.5 deg.. Decreasing the phase drift was achieved by the PID control program, and reducing the phase variation within a pulse width of 2 us was achieved by the adaptive control function on the VME modules. The unnecessary time jitters of the pulse were also automatically detected by the module function. In this paper, we describe a summary of the system and its phase control performance.
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THPMA081 | Precise Positioning of Magnetic Field Centers of Quadrupole Magnets on the Girder | quadrupole, alignment, synchrotron, target | 749 | ||||
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Conventional alignment of quadrupole magnet on the girder is mainly based on the measurement of theodolite and fiducial. Most of the measurement errors come from human-eye resolution and fiducial precision. The resultant cumulative error could be in the order of 50~100μm. In this paper, pulsed wire method is proposed to align group of quadrupole magnets concentrically on one girder to precision about 10μm. In order to increase the alignment accuracy, sag problem in tension wire is replaced by a short wire with laser PSD system. Descriptions of the setup and test results are presented.
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quadrupole magnet alignmentpsd |
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FRXMA01 | Progress of the Laser-Plasma Acceleration Research at KERI | plasma, electron, acceleration, background | 832 | ||||
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There rise great interest worldwide in plasma accelerators driven by ultra-intense lasers or electron beams which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short coherent X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world. Harnessing the recent advance of ultra-intense ultra-short pulse lasers and accelerators, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale. This talk highlights recent progress of results on laser and plasma based acceleration experiments to quest for physics of acceleration and beam physics in plasma and to present new outlook for applications of laser and plasma accelerators.
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