Status of the LBL experiment on femtosecond x-ray generation through 90(degree) Thomson scattering

摘要

A status report on the generation of femtosecond X-ray pulses through 90(degrees) Thompson scattering is presented. The experiment involves a relativistic electron beam (tunable from 25--50 MeV) with a bunch length of 10 ps containing 1 (minus)2 nC, and a ultrashort pulse (50--200 fs), high power (4 TW) 0.8 (mu)m Ti:Al(sub 2)O(sub 3) laser system. Both beams are focussed down to about a 50 (mu)m waist size and intersect at 90(degrees). The laser field acts as an electromagnetic undulator for the relativistic electron beam generating radiation upshifted by 2 (gamma)(sup 2) and a pulse length given by the transit time of the laser beam across the electron beam. For a 50 MeV electron beam we expect 10(sup 5) photons at 0.4 (angstrom) (10% bandwidth) in a cone angle of 6 mrad in a 170 fs pulse.