FEMTOSECOND ELECTRON-BEAM GENERATION AND MEASUREMENT FOR LASER SYNCHROTRON-RADIATION

One of the S-band twin linacs (18L linac) of Nuclear Engineering Resea rch Laboratory of University of Tokyo is modified in order to produce femtosecond electron single bunch for femtosecond X-ray generation via Thomson backward scattering, namely laser synchrotron radiation. Lase r photocathode RF gun and chicane-type magnetic pulse compressor are i nstalled at the S-band linac. 10 ps (FWHM) laser pulse generates 5 MeV , 10 ps (FWHM), 1 nC electron single bunch, which is accelerated up to 20 MeV in the S-band accelerating tube and compressed to 200 fs (FWHM ) by the chicane. Design study has been performed by using the code of PARMELA and the installation has been finished. For precise and relia ble measurement of the compressed pulse length, the comparison of meas urement between the femtosecond streak camera and coherent transition radiation interferotnetry was carried out. Good agreement between them for 1-10 ps (FWHM) pulses was achieved. A new Michelson interferomete r for the 200 fs pulse is now under construction. (C) 1998 Elsevier Sc ience B.V. All rights reserved.