共查询到20条相似文献,搜索用时 31 毫秒
1.
介绍了对一台脉冲线加速器驱动虚火花放电装置产的电子束发射度的测量工作。在十隙虚火花放电室中育以15Pa的氮气,产生能量为约200keV,束流2000A,直径为1mm和高亮度电子束。在距阳极5cm处测得电子束的均方根发射度εrms≈48mm.mrad,规一化发射率εn≈47mm.mrad。 相似文献
2.
A. G. Afonin G. I. Britvich A. P. Bugorskii M. K. Bulgakov A. A. Durum M. Yu. Kostin A. V. Lutchev V. A. Maisheev Yu. E. Sandomirskii V. I. Pitalev I. V. Poluektov Yu. A. Chesnokov P. N. Chirkov A. A. Yanovich 《JETP Letters》2016,104(1):12-14
At large accelerators, bent crystals are employed to deflect weakly divergent proton beams at the stages of extraction and collimation. We demonstrate that a divergent particle beam may be efficiently deflected using a crystal with a focusing edge. A proton beam with divergence near 1 mrad, which exceeds the Lindhard angle by a factor of 30, has been experimentally deflected by 1.8 mrad with efficiency near 15%. The proposed focusing crystal may serve as an element of a novel optical system for secondary-particle beams in the TeV energy region. 相似文献
3.
Wu XiaoBing Ouyang HuaFu Chi YunLong He Wei Huang Tao Li Gang Liu YingMan Lu YanHua Xu TaoGuang Zhang JunSong Zhang HuaShun Zhao FuXiang 《中国科学:物理学 力学 天文学(英文版)》2011,54(2):245-248
The accelerator complex of the China Spallation Neutron Source (CSNS) consists of a H− linear accelerator (linac) and a rapid cycling synchrotron (RCS). The linac contains a Penning surface H− ion source. The designed energy and the beam current of the source are 50 keV and 20 mA respectively, with a normalized root mean square (norm. rms.) emittance of 0.2π mm mrad. The manufactures and tests of the discharge chamber are in great progress. The construction of H− ion source test stand has been completed, and the operation of the source is also in progress. Stable H− ion beams with energy of 50 keV and current up to 50 mA are attained. Emittance measurement for the H− beam is being prepared.
相似文献4.
Tangential phase-matching has been realised in cesium lithium borate (CLBO) crystal for the first time for the generation
of fourth harmonic (266 nm) of Nd:YAG and third harmonic (226.7 nm) of a dye laser radiation by second harmonic generation
and sum-frequency mixing with the angular tolerance as large as 22 mrad and 21 mrad respectively, over one of the interacting
beams. An energy conversion efficiency of 15% for fourth harmonic generation is obtained with a 5.5 mm thick crystal and with
the average pump powers only 170 and 70 mW. A set of Sellmeier dispersion equations for the CLBO crystal have also been formulated. 相似文献
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L.C. Casper H.M.J. Bastiaens P.J.M. Peters K.-J. Boller R.M. Hofstra 《Applied physics. B, Lasers and optics》2007,88(1):61-66
The discharge quality and optimum pump parameters of a long-pulse high-pressure gas discharge excited KrCl laser are investigated.
A three-electrode prepulse–mainpulse excitation circuit is employed as pump source. The discharge volume contains a gas mixture
of HCl/Kr/Ne operated at a total pressure of up to 5 bar. For a plane–plane resonator, the divergence of both output laser
beams is measured. A low beam divergence of less than 1 mrad is measured as a result of the very high discharge homogeneity.
A maximum laser pulse duration of 150 ns (FWHM) is achieved for a pump duration of 270 ns (FWHM) and a power density of 340 kW cm-3. Pumping the discharge under optimum conditions employing a stable resonator results in a maximum specific energy of 0.45 J/l
with a laser pulse duration of 117 ns and an efficiency of 0.63% based on the deposited energy.
PACS 42.55.Lt; 52.25.-b; 52.59.Ye 相似文献
7.
X. Chen L. Canova A. Malvache A. Jullien R. Lopez-Martens C. Durfee D. Papadopoulos F. Druon 《Applied physics. B, Lasers and optics》2010,99(1-2):149-157
We report the routine generation of sub-5-fs laser pulses with 1-mJ energy and stable carrier–envelope phase at 1-kHz repetition rate, obtained by compressing the multi-mJ output from a phase-locked Ti:sapphire amplifier in a rare-gas-filled hollow fiber. The dual-stage amplifier features a hybrid transmission grating/chirped mirror compressor providing 2.2-mJ, 26-fs pulses at 1 kHz with standard phase deviation of 190 mrad rms. We demonstrate hour-long phase stability without feedback control of grating position or rigorous control of the laser environment, simply by using small pulse stretching factors in the amplifier, which minimize the beam pathway in the compressor. The amplifier also integrates a versatile AOPDF (acousto-optic programmable dispersive filter) for closed-loop spectral phase optimization. The various factors influencing the overall phase stability of the system are discussed in detail. Using the optimized output, 1-mJ, 4.5-fs pulses are generated by seeding the neon gas filled hollow fiber with a circularly polarized input beam. A standard phase deviation of 230 mrad after the HCF is obtained by direct f-to-2f detection and slow-loop feedback to the oscillator locking electronics without any additional spectral broadening. 相似文献
8.
A robust nonoptical carrier-envelope phase (CEP) locking feedback loop, which utilizes a measurement of the left-right asymmetry in the above-threshold ionization (ATI) of Xe, is implemented, resulting in a significant improvement over the standard slow-loop f-to-2f technique. This technique utilizes the floating average of a real-time, every-single-shot CEP measurement to stabilize the CEP of few-cycle laser pulses generated by a standard Ti:sapphire chirped-pulse amplified laser system using a hollow-core fiber and chirped mirror compression scheme. With this typical commercially available laser system and the stereographic ATI method, we are able to improve short-term (minutes) CEP stability after a hollow-core fiber from 450 to 290 mrad rms and long-term (hours) stability from 480 to 370 mrad rms. 相似文献
9.
Mehlhorn T.A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(6):1336-1356
Intense beams of light and heavy ions are being studied as inertial confinement fusion (ICF) drivers for high yield and energy. Heavy and light ions have common interests in beam transport, targets, and alternative accelerators. Self-pinched transport is being jointly studied. This article reviews the development of intense ion beams for ICF. Light-ion drivers are highlighted because they are compact, modular, efficient and low cost. Issues facing light ions are: (1) decreasing beam divergence; (2) increasing beam brightness; and (3) demonstrating self-pinched transport. Applied-B ion diodes are favored because of efficiency, beam brightness, perceived scalability, achievable focal intensity, and multistage capability. A light-ion concept addressing these issues uses: (1) an injector divergence of ⩽24 mrad at 9 MeV; (2) two-stage acceleration to reduce divergence to ⩽12 mrad at 35 MeV; and (3) self-pinched transport accepting divergences up to 12 mrad. Substantial progress in ion-driven target physics and repetitive ion diode technology is also presented. Z-pinch drivers are being pursued as the shortest pulsed power path to target physics experiments and high-yield fusion. However, light ions remain the pulsed power ICF driver of choice for high-yield fusion energy applications that require driver standoff and repetitive operation 相似文献
10.
A. V. Sidorov V. G. Zorin I. V. Izotov S. V. Razin V. A. Skalyga 《Technical Physics》2010,55(10):1540-1542
Experimental data for generating intense beams of multiply charged heavy gas ions are reported. The beams are extracted from
the dense plasma of an ECR discharge with quasi-gasdynamic confinement provided by the powerful microwave radiation of a gyrotron
in a magnetic trap. The axisymmetric magnetic trap makes it possible to extract uniform (in transverse coordinates) plasma
fluxes from it, and the use of a multiple-aperture extraction system makes it possible to increase the beam current by more
than an order of magnitude compared with the ECP sources currently available. Multiply charged nitrogen ion beams with a current
of 150 mA and a normalized emittance of 0.9π mm mrad are obtained. 相似文献
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Noboru Nakatani 《Optical Review》2003,10(4):206-210
This paper describes a compulsorily phase locked differential interferometer using an orthogonally polarized light source of a modulated LD with high extinction ratio to reduce non-linearity of the interferometer caused by polarization cross-talk. The current modulated LD is used as a light source to make the interferometer compact and for the scanning phase of the interferometer. The interferometer is operated compulsorily at the maximum inclination point of the fringe intensity curve by fringe scanning and an electric system. A Wollaston prism of high extinction ratio (50 dB) is used to combine the polarizing beams and to make the polarization cross-talk very small. In one light source the polarized output beams are on the same propagation axis; in the other they have a small crossing angle (2.5 mrad ∼ 10 mrad) to completely exclude non-linearity of the interferometer causded by polarization cross-talk. Using jets of a gas mixture of nitrogen and ethylene, this interferometer was demonstrated to be useful in detecting the photothermal effect of a photothermal velocimeter under phase fluctuation in a turbulent flow. 相似文献
13.
利用“泵浦-探测”非共线双等离子体通道方法实现三次谐波增强。泵浦光与探测光间的耦合作用能有效改善探测光光丝中的饱和效应,克服光强钳制对谐波强度增加的限制。实验中将两束能量分别为4.4和10.2 mJ、中心波长均为810 nm、脉宽均为60 fs的超短脉冲在空气中非共线聚焦,能各自形成光丝且产生微弱三次谐波。当强光在时域上超前于弱光时,强光会预先成丝形成等离子体通道,对后续弱光产生调制,使探测光产生的三次谐波强度明显增强。实验发现270 nm谐波能量增加的显著区域内频谱宽度出现振荡变化,当两光以27.3 mrad小角度相交于几何焦点前约15 mm,且探测光滞后约55 fs时,获得的能量增长倍率达到近70倍,对应谱宽约为5 nm。 相似文献
14.
We report on a low-noise diode laser oscillator at 972?nm actively stabilized to an ultrastable vibrationally and thermally compensated reference cavity. To increase the fraction of laser power in the carrier we designed a 20?cm long external cavity diode laser with an intracavity electro-optical modulator. The fractional power in the carrier reaches 99.9%, which corresponds to an rms phase noise of φ(rms)2=1?mrad2 in 10?MHz bandwidth. Using this oscillator, we recorded 1S-2S spectra in atomic hydrogen and have not observed any significant loss of the excitation efficiency due to phase noise multiplication in the three consecutive two-photon processes. 相似文献
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Rousse A Phuoc KT Shah R Pukhov A Lefebvre E Malka V Kiselev S Burgy F Rousseau JP Umstadter D Hulin D 《Physical review letters》2004,93(13):135005
We demonstrate that a beam of x-ray radiation can be generated by simply focusing a single high-intensity laser pulse into a gas jet. A millimeter-scale laser-produced plasma creates, accelerates, and wiggles an ultrashort and relativistic electron bunch. As they propagate in the ion channel produced in the wake of the laser pulse, the accelerated electrons undergo betatron oscillations, generating a femtosecond pulse of synchrotron radiation, which has keV energy and lies within a narrow (50 mrad) cone angle. 相似文献
17.
Uesaka M. Kinoshita K. Watanabe T. Sugahara J. Ueda T. Yoshii K. Kobayashi T. Hafz N. Nakajima K. Sakai F. Kando M. Dewa H. Kotaki H. Kondo S. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(4):1133-1142
The feasibility of the laser photocathode RF gun, BNL/GUN-IV, as an injector for a laser plasma accelerator was investigated at the subpicosecond S-band twin linac system of the Nuclear Engineering Research Laboratory, University of Tokyo. Electron beam energy of 16 MeV, emittance of 6π mm mrad, bunch length of 240 fs (FWHM), and charge per bunch of 350 pC were confirmed at 10 Hz. As for diagnosis of the femtosecond electron bunch, the quantitative comparison of performance of the femtosecond streak camera, the coherent transition radiation (CTR) Michelson interferometer, and the far-infrared polychromator was carried out. We concluded that the streak camera is the most reliable up to 200 fs and that the polychromator is the best for the shorter electron bunch. The 3.5-ps (rms) resolved synchronization between the YLF laser driver for the gun and the electron bunch was achieved. Based on the above experiences, we have designed and installed a much better laser-electron synchronization system using the Kerr-lens mode-locked Ti:Sapphire laser with the min harmonics synchrolocker and the stable 15-MW klystron. The timing jitter is expected to be suppressed down to 320 fs (rms) 相似文献
18.
L. L. Nagornaya V. D. Ryzhikov U. Ya. Vostretsov I. A. Tupitsina S. F. Burachas W. P. Martynov K. A. Katrunov 《Radiation measurements》1995,24(4):375-377
New very promising heavy fast PbWO4 crystals as radiators for dense high resolution photon calorimeters were studied in this paper. Radiation detector parameters obtained with the real-size calirometer cells are presented. It was shown that owing to high density and transparency, quick response (4 ns), high radiation stability (about 10 mrad) with energy resolution 1% at an energy above 1 GeV, the PbWO4-based scintillators are a most advantageous candidate for the creation of total absorption compact detectors of EM caorimeters. 相似文献
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强流重离子加速器装置(HIAF)将采用电子冷却技术,降低重离子束流的发射度和动量分散,提高核物理及原子物理实验的精度与亮度。电子冷却装置的冷却段磁场均匀度是影响冷却效率的主要参数,HIAF电子冷却装置采用多个独立高精度线圈串联产生纵向磁场的设计,获得极高的冷却段磁场均匀度。本文介绍了一种测量高精度线圈磁轴偏角的装置,采用定位装置测量线圈的几何对称轴,通过旋转霍尔探头测量线圈中心平面上的径向与轴向磁场分布,再根据磁场测量数据计算出线圈磁轴与几何对称轴之间的偏角。实际测量表明该装置的磁轴偏角测量精度达到±0.10 mrad。测量得到的HIAF电子冷却装置冷却段线圈样品的磁轴偏角为(1.28±0.10)mrad,达到设计要求。 相似文献