共查询到20条相似文献,搜索用时 78 毫秒
1.
Lefevre T Gardelle J Rullier JL Vermare C Donohue JT Meurdesoif Y Lidia SM 《Physical review letters》2000,84(6):1188-1191
An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, which was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with the simple formula which relates power to known properties of both the beam and the cavity. 相似文献
2.
BXERL is a proposal for a test facility(Beijing X-ray Energy Recovery Linac),which requires its injector to provide an electron beam of 5 MeV,77 pC/ bunch at a repetition rate of 130 MHz(average current of 10 mA).In this paper,we present the design of the injector,which consists of a 500 kV photocathodeDC gun equipped with a GaAs cathode preparation device,a 1.3 GHz normal conducting RF buncher,two solenoids,and one cryomodule containing two 1.3 GHz 2-cell superconducting RF cavities as the energy booster.The detailed beam dynamics show that the injector can generate electron bunches with a RMS normalized emittance of 1.49 7rmm-mrad,a bunch length of 0.67 mm,a beam energy of 5 MeV and an energy spread of 0.72%. 相似文献
3.
Gardelle J. Lefevre T. Marchese G. Rullier J.-L. Donohue J.T. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(6):1419-1424
We report output power and frequency measurements of a pulsed free electron laser (FEL) operating as an amplifier at 35 GHz, without guiding field. The experiment used an induction linac, which delivers an 800-A relativistic electron beam (2.2 MeV) with a flat-top of 40 ns into the helical wiggler. The input signal furnished by a 35-GHz magnetron source is amplified to power levels of the order of 80 MW. The experimental results are in good agreement with our simulations. Frequency chirping is observed, and its behavior as a function of the basic FEL parameters is discussed 相似文献
4.
K.Kawase M.Kando T.Hayakawa I.Daito S.Kondo T.Homma T.Kameshima H.Kotaki L.Chen Y.Fukuda A.Faenov Shizuma S.V.Bulanov T.Kimura T.Tajima M.Shoji S.Suzuki K.Tamura H.Ohkuma Y.Arimoto T.Yorita M.Fujiwara S.Okajima 《原子核物理评论》2009,26(Z1)
Recently we have constructed two facilities for generating photon beams in the MeV and sub-MeV energy regions by means of the Compton backscattering with a laser and an electron beam at SPring-8 and at Kansai Photon Science Institute of Japan Atomic Energy Agency(KPSIJAEA).The MeV-photon source at SPring-8 consists of a continuous-wave optically-pumped far infrared laser with a wavelength of 118.8 μm and an 8 GeV stored electron beam.Present MeV-photon flux is estimated to be 1.3×10~3 photons/s.On the other hand,the sub-MeV-photon source at KPSI-JAEA consists of a pulse Nd:YAG laser with a wavelength of 1 064 nm and a 150 MeV electron beam accelerated by microtron.In the first trial of the photon production in this source,backscattered photon flux is estimated to be 20 photons/pulse.Both the Compton backscattered photon sources have possibilities to be used for new tools in various fields such as nuclear physics,materials science,and astronomy. 相似文献
5.
Musumeci P Tochitsky SY Boucher S Clayton CE Doyuran A England RJ Joshi C Pellegrini C Ralph JE Rosenzweig JB Sung C Tolmachev S Travish G Varfolomeev AA Varfolomeev AA Yarovoi T Yoder RB 《Physical review letters》2005,94(15):154801
Energy gain of trapped electrons in excess of 20 MeV has been demonstrated in an inverse-free-electron-laser (IFEL) accelerator experiment. A 14.5 MeV electron beam is copropagated with a 400 GW CO2 laser beam in a 50 cm long undulator strongly tapered in period and field amplitude. The Rayleigh range of the laser, approximately 1.8 cm, is much shorter than the undulator length yielding a diffraction-dominated interaction. Experimental results on the dependence of the acceleration on injection energy, laser focus position, and laser power are discussed. Simulations, in good agreement with the experimental data, show that most of the energy gain occurs in the first half of the undulator at a gradient of 70 MeV/m and that the structure in the measured energy spectrum arises because of higher harmonic IFEL interaction in the second half of the undulator. 相似文献
6.
Mackinnon AJ Sentoku Y Patel PK Price DW Hatchett S Key MH Andersen C Snavely R Freeman RR 《Physical review letters》2002,88(21):215006
MeV-proton production from solid targets irradiated by 100-fs laser pulses at intensities above 1x10(20) W cm(-2) has been studied as a function of initial target thickness. For foils 100 microm thick the proton beam was characterized by an energy spectrum of temperature 1.4 MeV with a cutoff at 6.5 MeV. When the target thickness was reduced to 3 microm the temperature was 3.2+/-0.3 MeV with a cutoff at 24 MeV. These observations are consistent with modeling showing an enhanced density of MeV electrons at the rear surface for the thinnest targets, which predicts an increased acceleration and higher proton energies. 相似文献
7.
BXERL is a proposal for a test facility (Beijing X-ray Energy Recovery Linac), which requires its injector to provide an electron beam of 5 MeV, 77 pC/ bunch at a repetition rate of 130 MHz (average current of 10 mA). In this paper, we present the design of the injector, which consists of a 500 kV photocathode DC gun equipped with a GaAs cathode preparation device, a 1.3 GHz normal conducting RF buncher, two solenoids, and one cryomodule containing two 1.3 GHz 2-cell superconducting RF cavities as the energy booster. The detailed beam dynamics show that the injector can generate electron bunches with a RMS normalized emittance of 1.49 πmm·mrad, a bunch length of 0.67 mm, a beam energy of 5 MeV and an energy spread of 0.72%. 相似文献
8.
TRIUMF 的三期升级工程(ARIEL) 计划建造一个 50 MeV 平均流强为10 mA的电子直线加速器作为注入器,通过光裂反应生成放射性核素。电子直线加速器包括两个主要部分:注入器和后加速器,注入器完成电子能量从100 keV到10 MeV的转换,随后的后加速器将电子能量从10 MeV加速到50 MeV。电子源拟采用重复频率为650 MHz的热电子枪提供初始能量为100 keV,束长为 171 ps的电子束。束流动力学模拟了几种不同的设计方案以获得最优化的设计,模拟显示通过对腔体以及聚焦元件的仔细设计以及电子枪出射电子的参数选择, 电子束能量在达到50 MeV时束长可以被聚焦到 11.75 ps (对应于1.3 GHz 频率下5.5°) ,并且可以使电子束在超导低温柜中的尺寸保持在1.26 cm以下。 相似文献
9.
金晓 许州 杨兴繁 蔡公和 沈旭明 邓仁培 黎明 都兴绍 杨茂荣 李正红 钱民权 蔡琳 潘清 程云 刘捷 卢和平 赵夔 张保澄 王莉芳 谢大林 郝建奎 胡克松 周传明 《强激光与粒子束》2001,13(6):769-772
光阴极超导加速器实验系统由四倍频Nd:YAG锁模激光器、Cs2Te光阴极、2+1/2微波电子枪、L波段3.5MW脉冲微波源,1.3GHz单腔超导铌腔,500W连续微波源,超导腔束管耦合器,4.2K低温恒温容器,液氦制冷系统,同步控制系统,束流参数诊断,真空系统等构成。2001年6月在中物院进行了光阴极超导加速器原理性实验,测得超导加速段能量增益0.58MeV,微脉冲束流强度0.1A,取得了预期的实验结果。 相似文献
10.
Hill ME Adolphsen C Baumgartner W Callin RS Lin XE Seidel M Slaton T Whittum DH 《Physical review letters》2001,87(9):094801
We report the first high-gradient studies of a millimeter-wave accelerator, employing for the first time a planar dielectric accelerator, powered by means of a 0.5-A, 300-MeV, 11.424-GHz drive electron beam, synchronous at the 8th harmonic, 91.392 GHz. Embedded in a ring-resonator circuit within the electron beam line vacuum, this structure was operated at 20 MeV/m, with a circulating power of 200 kW, for 2 x 10(5) pulses, with no sign of breakdown, dielectric charging, or other deleterious high-gradient phenomena. We also present the first measurement of the quadrupolar content of an accelerating mode. 相似文献
11.
We propose a new technique for reducing speckle noise in laser displays utilizing a high-speed optical phase modulator for expanding the laser beam spectrum. By adopting standing-wave resonant electrodes and polarization-reversed structures to LiTaO3 electro-optic modulators, high-efficiency phase modulation with a large modulation index at high microwave frequency ranges is obtainable for different color laser beams at the same time. This enables us to expand laser spectra to over 100 GHz and reduce speckle noise. The device design, fabrication, and experimental demonstration for speckle control are reported. 相似文献
12.
We report the testing of a high gradient electron accelerator with a photonic-band-gap (PBG) structure. The photonic-band-gap structure confines a fundamental TM(01)-like accelerating mode, but does not support higher-order modes (HOM). The absence of HOM is a major advantage of the PBG accelerator, since it suppresses dangerous beam instabilities caused by wakefields. The PBG structure was designed as a triangular lattice of metal rods with a missing central rod forming a defect confining the TM(01)-like mode and allowing the electron beam to propagate along the axis. The design frequency of the six-cell structure was 17.14 GHz. The PBG structure was excited by 2 MW, 100 ns pulses. A 16.5 MeV electron beam was transmitted through the PBG accelerator. The observed electron beam energy gain of 1.4 MeV corresponds to an accelerating gradient of 35 MV/m, in excellent agreement with theory. 相似文献
13.
M. Roth A. Blazevic E. Brambrink M. Geissel T. E. Cowan J. Fuchs A. Kemp H. Ruhl P. Audebert J. Cobble J. Fernandez M. Hegelich S. Letzring K. Ledingham P. McKenna R. Clarke D. Neely S. Karsch D. Habs J. Schreiber 《Hyperfine Interactions》2005,162(1-4):45-53
Intense beams of protons and heavy ions have been observed in ultra-intense laser-solid interaction experiments. Thereby,
a considerable fraction of the laser energy is transferred to collimated beams of energetic ions (e.g. up to 50 MeV protons;
100 MeV fluorine), which makes these beams highly interesting for various applications. Experimental results indicate very
short pulse duration and an excellent beam quality, leading to beam intensities in the TW range. To characterize the beam
quality and its dependence on laser parameters and target conditions, we performed experiments at several high-power laser
systems. We found a strong dependence on the target rear surface conditions allowing to tailor the ion beam by an appropriate
target design. We also succeeded in the generation of heavy ion beams by suppressing the proton amount at the target surface.
We will present recent experimental results demonstrating a transverse beam emittance far superior to accelerator-based ion
beams. Finally, we will discuss the prospect of laser-accelerated ion beams as new diagnostics in laser-solid interaction
experiements. Special fields of interest are proton radiography, electric field imaging, and relativistic electron transport
inside the target. 相似文献
14.
Dispersive solid-state dye laser oscillators 总被引:1,自引:0,他引:1
F. J. Duarte A. Costela I. Garcia-Moreno R. Sastre J. J. Ehrlich T. S. Taylor 《Optical and Quantum Electronics》1997,29(4):461-472
Narrow-linewidth multiple-prism grating solid-state dye laser oscillators are analysed using ray transfer matrices. Attention
is given to beam divergence measurements and the effect on them of thermal lensing, at the solid-state gain medium. It is
found that although thermal lensing leads to an increment of beam divergence, it induces oscillation in the unstable resonator
regime, thus contributing to the attainment of TEM00 beam profiles. In addition, narrow-linewidth emission in dispersive oscillators,
incorporating rhodamine 6 G doped HEMA:MMA gain media, is reported for the first time. Laser efficiency is 4–5% at a laser
linewidth ≤1.8 GHz for double-longitudinal-mode emission. Beam divergence is measured in the 2–2.3 mrad range, in good agreement
with theory.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
15.
Modena A. Najmudin Z. Dangor A.E. Clayton C.E. Marsh K.A. Joshi C. Malka V. Darrow C.B. Danson C. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(2):289-295
Raman forward scattering (RFS) is observed in the interaction of a high intensity (>1018 W/cm2) short pulse (<1 ps) laser with an underdense plasma (ne~1019 cm -3). Electrons are trapped and accelerated up to 44 MeV by the high-amplitude plasma wave produced by RFS. The laser spectrum is strongly modulated by the interaction, showing sidebands at the plasma frequency. Furthermore, as the quiver velocity of the electrons in the high electric field of the laser beam becomes relativistic, various effects are observed which can be attributed to the variation of electron mass with laser intensity 相似文献
16.
17.
The high-frequency modulation characteristics of GaAs-based bipolar cascade vertical cavity surface-emitting lasers operating at 980 nm with GaAs tunnel junctions and p-doped Al0.98Ga0.02As oxide apertures have been measured. We achieve -3 dB laser output modulations of 6.5 GHz for two-stage and 9.4 GHz for three-stage devices in response to small-signal current injection at an operating temperature of -50 degrees C. 相似文献
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20.
A prototype of a laser driven proton accelerator is built at Peking University. Protons exceeding 10 MeV are accelerated from micrometer-thick aluminum targets irradiated by tightly focused laser pulse with 1.8 J energy and 30 fs duration. The beam energy spectrum and charge distribution are measured by a Thomson parabola spectrometer and radiochromic film stacks. The sensitivity of proton cut-off energy to the focusing of the laser beam, the pulse duration, and the foil thickness are systematically investigated in the experiments. Stable proton beams have been produced with an optimized parameter set, providing a cornerstone for the future applications of laser accelerated protons. 相似文献