Methods for characterizing x-ray detectors for use at the National Ignition Facility

Area of Science:

• High-energy-density physics
• Plasma physics
• X-ray detection technology

Background:

• Gated and streaked x-ray detectors require corrections for instrumental effects.
• Gain variations in gated cameras at the National Ignition Facility (NIF) necessitate calibration.
• Current characterization methods involve dedicated laser-plasma shots at NIF.

Purpose of the Study:

• To describe methods for correcting gain variations in NIF gated x-ray cameras.
• To introduce a recently commissioned pulsed x-ray source for detector characterization.
• To evaluate the potential of this new source as an alternative to existing techniques.

Main Methods:

• Characterization of gated x-ray detectors using four distinct techniques.
• Utilizing laser-generated plasmas for controlled x-ray emission at NIF.
• Employing a new pulsed x-ray source (Marx generator, capacitor bank, up to 300 kV) for characterization.

Main Results:

• A new pulsed x-ray source has been commissioned, offering potential replacement for current characterization systems.
• Initial jitter of the pulsed x-ray source (∼60 ns) was significantly reduced to ∼5 ns by incorporating a pulsed laser trigger.
• The pulsed x-ray source demonstrates promising results as an alternative to traditional flat fielding techniques.

Conclusions:

• The developed pulsed x-ray source is a viable and promising alternative for calibrating gated x-ray detectors.
• Reducing jitter in the pulsed x-ray source enhances its reliability for detector characterization.
• This advancement contributes to more accurate data acquisition from x-ray diagnostics at NIF.