THE X-RAY-RADIATION FROM VACUUM DISCHARGES AT COMPARATIVELY LOW APPLIED VOLTAGES

The temporal evolution of X-ray emission of laser-induced discharges w as investigated by means of a picosecond X-ray streak camera. Point-li ke structures with small divergence (of order 8 x 10(-6)) and thin hot layers of intense X-ray radiation with life-time from 30 ps to 1.5 ns in a spectral range 100 eV-10 keV have been found for the first time in a comparatively low voltage vacuum discharge (U approximate to 150 V-2.7 kV) initiated by a picosecond laser beam. The radiation of laser -induced breakdown was investigated just after breakdown as well as wi th a long delay time (up to 20 ns) relative to the ignition point by t he laser beam in order to eliminate the X-ray radiation coming from th e laser-produced plasma. (C) 1998 Elsevier Science B.V.