Particle Transport Simulations in Support of Laser-Based X-ray Radiography*

Novel MeV x-ray sources based on high-power short-pulse lasers have the potential to revolutionize radiography with their small spot size, short pulse duration, low cost, and flexibility. In this poster, we report on using the particle transport code MCNP in aid of laser-based x-ray radiography by 1) analyzing and optimizing the electron to x-ray bremsstrahlung converters, and 2) analyzing filter-stack spectrometers to successfully unfold the incident spectrum from the raw image plate data in experiments. Laser-based x-ray radiography uses short-pulse lasers to accelerate electrons, and a high-Z millimeter-scale converter to produce x-rays. Optimization of this converter is critical to efficiently use the incident electrons to best radiographic effect. We assess trade-offs among desired x-ray energy, effects on spot size, and electron blocking. Unfolding spectra from filter-stack spectrometers requires a detailed response matrix—the average energy deposited in each image plate per incident photon at a certain energy. We present a software stack to streamline this process.