Development of a scintillator-based x-ray imager for high resolution backlit x-ray radiography experiments*

 The National Ignition facility allows us to explore extreme physics conditions that could have never been accessed. However, the observation of such extreme conditions requires new diagnostic capabilities as well. Observation of significantly nonlinear growth of hydrodynamic instabilities driven by multiple colliding shock waves requires backlit imaging of small perturbations while recording larger structures at the scale of the initial perturbation. Under the current experimental design, observation of the material flow transitioning into turbulence requires spatial resolution of less than 3 μm while keeping a wide field of view of 600 μm.

 

To satisfy these requirements, we designed a new imaging setup which is a combination of a pulsed laser driven x-ray backlit source (hν ~ 7.2 KeV), a bent crystal x-ray imager (x-ray image magnification 10x), and a newly developed scintillator-based x-ray imager. The scintillator-based x-ray imager consists of a scintillator screen (LuAG:Ce, 100 μm thick) and an industrial lens (image magnification: 3.33x, NA 0.158), and a CMOS imager. To satisfy the required SNR with a given intensity of the x-ray source, we need a new imaging detector with spatial resolution better than 20 μm at the scintillator while having DQE better than 10%.

 

We assembled a proof-of-principle setup of the imager and evaluated basic performance parameters. We will discuss the obtained performance and compare it to an analytical model of the system.