In vacuum operating picosecond streak camera for x-ray diagnostics

Abstract

The CEA is developing a high energetic laser Facility for large scale investigations on plasma physics. This facility named Laser Megajoule (LMJ) will offer 240 laser beams and 1.8 MJ pulse energy is 3 ns. These laser beams will impact a target at the center of a large spherical chamber, for experiments by means of fusion by inertial confinement. We describe here a prototype of insertable Streak camera for hard X-ray experiments specifically designed to operate in vacuum ( -6 mbar) near the target chamber. The Streak tube is based on an open and modular structure of cylindrical electrodes with a large photocathode (approximately 20 mm). Time window ranges from 1 ns up to 25 ns with triggering jitter less than 10 ps rms. The readout is made by a specific high dynamic cooled CCD camera. Cooling system (Peltier stage combined with water flow) allows a -10°C stabilized temperature on chip. The CCD camera is an ATMEL product comprising a (2048 x 2048) matrix of 14 μm square pixels. Digitizing is performed by a 16 bits conversion chain with 6 electrons readout noise. First results obtain on the Streak tube electronics and CCD camera are presented (MTF, CCD, S/N, flat field, temporal jitter and linearity or temporal resolution...). Time bandwidth estimated for this camera for the 1 ns base time will be of 45 GHz at -3 dB.