X-ray intensity, stability, and source size characterizations for the 10 kV/5 mA water cooled upgraded Manson source at the Atomic Energy Commission for Laser MégaJoule Facility.

Abstract

Calibration of x-ray cameras integrated within plasma diagnostics for Laser MégaJoule's experiment is of great interest for interpretations of physical phenomena. At the Atomic Energy and Alternative Energy Commission, an x-ray calibration laboratory has been trying for many years to provide the most relevant calibrations. In the soft x-ray range (<1.5 keV), a model 5 Manson source is used in combination with a concave grating monochromator equipped permanently with an absolute calibrated silicon drift detector. To reduce the calibration time achieved with this experimental setup, the Manson source has been modified to reach an emission current of up to 5 mA (100 µA for a standard source model) while keeping the x-ray monochromatic intensity constant within ∼2% for several operating hours. A water cooling system has been integrated within the anode carousel and an emission current regulation system inside a completely redesigned power supply. In this work, we present characterization of the source size and x-ray intensity as a function of both source voltage and emission current, as well as the stability of this new source. Both arms of the source have been used: one for monitoring the monochromatic spectra and x-ray intensity and the other to measure the source size. An x-ray spot was observed to be evolved from the oval shape toward the annular one as the emission current increases. For fixed emission current, the source size is reduced as the voltage increases. The x-ray intensity has significantly been increased to a maximum factor of ∼20 (depending on the anode) while being constant within around 2% as expected.