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Achromatically filtered diamond photoconductive detectors for high power soft x-ray flux measurements

1999; American Institute of Physics; Volume: 70; Issue: 1 Linguagem: Inglês

10.1063/1.1149385

1527-2400

R. E. Turner, O. L. Landen, P. Bell, R. Costa, D. Hargrove,

Laser-Plasma Interactions and Diagnostics

A 1-mm-square diamond photoconductive detector (PCD) has been installed on the LLNL Nova laser system, for use as a broadband soft x-ray power diagnostic. The PCD is installed behind an array of pinholes, which cast multiple, overlapping images of the source onto the diamond. This allows reduction of the x-ray intensity, to avoid saturation problems, while avoiding the spectral dependency of thin film filters. The diode current is read out on a 5 GHz bandwidth scope. The system is calibrated by comparison to an absolutely calibrated array of filtered vacuum x-ray photodiodes (“dante”). The time response of the PCD and its bias electronics have been characterized using the 5th harmonic (210 nm) of a short pulse (<1 ps) Ti: sapphire laser. The data show a fast rise, limited by the 5 GHz scope bandwidth, and a slower fall off, characterized by an RC time of order 200 ps.