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Peak intensities of 1019 W cm2 have been reliably obtained from a high power Nd:glass laser using chirped pulse amplification. An Additive Pulse Modelocked oscillator incorporating diode pumped Nd:LMA was used to generate the sub-picosecond pulse. The focal spot intensity distribution has been characterized in detail showing a three times diffraction limited beam.

The Vulcan Nd:glass laser at the Central Laser Facility (CLF) has recently been upgraded to the Petawatt level (10 15 Watts). The facility is now operational to the UK and international user community. During the first user experiments, the power and focussed intensity were increased gradually up to the Petawatt regime. Considerable experience has been gained operating the Vulcan facility in this mode. The Petawatt facility is designed to deliver irradiance on target of 10 21 W.cm -2 for a wide-ranging experimental programme in fundamental physics and advanced applications. This includes the interaction of super-high intensity light with matter, fast ignition fusion research, photon induced nuclear reactions, electron and ion acceleration by light waves and the exploration of the exotic world of plasma physics dominated by relativity.

Vulcan is established as a world leading user facility for studies of ultra-high intensity laser interactions with matter. The Petawatt(PW) Upgrade project will deliver an order of magnitude increase in laser power to target, delivering interaction intensities of 10 21 Wcm -2. Before commencing operation to users a commissioning study was carried out. The objectives of this investigation were: To perform radiological surveys of the facility in anticipated target configurations and to install additional shielding for high-Z interactions as required To measure the target irradiance and the X-ray spot size To investigate the effects of electromagnetic noise on the chamber and target area equipment To determine the level of debris produced from the target and to devise a suitable operating scheme to protect chamber optics from damage Installation of an optical probe Contrast measurement of the laser pulses This report will review the experimental and radiological data obtained from the thirteen solid target interaction shots fired during the commissioning run in the newly constructed PW interaction facility 1) where doses of 45 mSv @ 1m were obtained. Commissioning of the PW laser and compressor chain is reported in separate articles, as is the commissioning of the large aperture gratings at high laser fluences 2).