远红外自由电子激光装置束流传输线的设计与整体数值模拟  

DESIGN AND INEX SIMULATIONS OF THE ELECTRON-BEAM TRANSPORT LINE FOR THE CAEP FIR-FEL FACILITY

作　　者：吴中发[1] 王玉芝[1] 

机构地区：[1]北京应用物理与计算数学研究所

出　　处：《强激光与粒子束》1995年第2期235-244,共10页High Power Laser and Particle Beams

摘　　要：提出了ＣＡＥＰ（中国工程物理研究院）远红外自由电子激光装置束流传输线的设计，给出了各元件的设计参数，并进行了束流传输整体数值模拟，最后得到摇摆器入口处电子束团的主要参数：能量２ＭｅＶ，峰值电流１７Ａ，脉冲宽度１４ｐｓ（ＦＷＨＭ），束归一化发时度１４πｍｍ·ｍｒａｄ（水平）和５πｍｍ·ｍｒａｄ（垂直），束团整体能散度１．２７％，束归一化亮度５×１０￣（１０）Ａ／ｍ￣２·ｒａｄ￣２。整体数值模拟结果表明：电子束品质完全满足摇摆器的要求。AbstractCAEP is developing the FIR-FEL Facility.We optimize design by the integratednumerical experiment(INEX)for offering electron beam whose parameters should be fit forthe requirements of the wiggler.Our INEX code include modified PARMELA,MWG andsome supplementary code.The requirements of the beamline design:1.selecting energy spread and compressingpulse width of the electron beam with a-magnet.2.making e-beam enters plane guidefrom the side,transport 72cm in the plane guide which has 5mm gap,at the same timeinsuring electrons don′t decrease and beam characters don′t deteriorate (Fig.1).Our principle:After e-beam coming out ofα-magnet,we press it flat, its halfenvelope(vertical)is less than 0.5mm,when it reachcs theentrance of the bendigg magnetwith the quadruple doublet.Next,we make flat beam pass through the achromatic bendingsystem and insure it not to defocus(vertical)at the exit of the bending magnet,shortlye-beam enters the wiggler.According to our principle,we studied e-beam movement law in the thermioniccathode microwave e-gun,a-magnet,achromatic bending systemand wiggler.Ignoringspace charge,we find out the relation between element parameters of the achromaticbending system and electron beam movement state,Fig.10～Fig.12 indicate the envelope ofelectrons in the elements.Finally,under selected system parameters,INEX simulations show that the followinge-beam parameters at the wiggler entrance can be assured.The beam energy is 2MeV,peakcurrent 17A,micropulse length 14ps(FWHM),energy spread (whole)1.27%,normalizedhorizontal emittance 14mm · mrad and normalized vertical 5mm·mrad.and normalizedbrightness 5 ×10￣(10)A/m￣2·rad￣2,these parameters can be well matched with the wiggler.

关 键 词：远红外 自由电子激光 束流传输线 数值模拟 

分 类 号：TN248.6[电子电信—物理电子学]