We report the high energy radiography of dense material using MeV all-optical-driven inverse Compton x-ray source. The properties of the inverse-Compton x-ray source are controlled by means of electron energy, electron charge, scattering beam focal spot size and pulse duration to obtain optimized x-ray energy and high flux for dense material radiography. In this experiment, the x-ray has a photon energy of 8 MeV for maximal steel penetration depth, and a flux of 1011 x-ray photons per shot. With this novel x-ray source, we are able to demonstrate radiography of a 10 cm thick “kite” object through a steel shielding with thickness up to 40 cm in a single exposure. The radiography image of the “kite” object though the 40 cm steel has signal to noise ratio of 2 and image contrast of 0.1, and the “kite” object can be clearly distinguished in the image. Combining its tunability, ultrafast pulse duration and micron meter resolution, the all-optical-driven inverse Compton x-ray source provides unique capacities for flash radiography of dense material, and is of interest for ultrafast nuclear physics study.
The recent development of a high-brightness MeV-photon source based on inverse-Compton scattering (ICS) has opened
up exciting new possibilities for high-resolution radiography of dense objects. The x-ray beam is extremely bright,
micron-source size, with mrad divergence, and high-spectral density, which makes it ideal for studies where high-resolution
is required. The x-ray source is tunable over a wide range of parameters and we will discuss how the
adjustable source parameters affect both transverse and longitudinal resolution. We then present results on the
radiography of a thick steel object using this ICS source, and demonstrate the capabilities of this source with respect to
operation at high photon energy while providing high spatial resolution.
The laser-driven Thomson scattering light source generates x-rays by the scattering of a high-energy electron beam off a high-intensity laser pulse. We have demonstrated that this source can generate collimated, narrowband x-ray beams in the energy range 0.1-12 MeV. In this work, we discuss recent results on the application of this source for radiography and photonuclear studies. The unique characteristics of the source make it possible to do this with the lowest possible dose and in a low-noise environment. We will also discuss recent experimental results that study nuclear reactions above the threshold for photodisintegration and photofission. The tunable nature of the source permits activation of specific targets while suppressing the signal from background materials.
A two-step algorithm is developed that can reconstruct the full 3-D molecular structure from diffraction patterns of
partially aligned molecules in gas phase. This method is applicable to asymmetric-top molecules that do not need to have
any specific symmetry. This method will be important for studying dynamical processes that involve transient structures
where symmetries, if any, can possibly be broken. A new setup for the diffraction experiments that can provide enough
time resolution as well as high currents suitable for gas phase experiments is reported. Time resolution is obtained by
longitudinal compression of electron pulses by time-varying electric fields synchronized to the motion of electron pulses.