One-shot x-ray detection based on the instantaneous change in the refractive index of GaAs

Abstract

An interferometric semiconductor x-ray detection system is proposed in this paper. The system is based on the RadOptic effect, and it utilizes Fabry–Perot interferometry to measure radiation-induced changes in the optical refractive index of a semiconductor (GaAs). In this work, the intrinsic time resolution and the sensitivity of a Fabry–Perot interferometric sensor were systemically studied. Based on the transient free carrier absorption model, the prototype system was established to quantitatively measure the time-dependent x-ray flux with the deconvolution algorithm for the first time. The time resolution of the detection system was approximately 21 ps, and the output signal induced by an x-ray pulse showed a high signal-to-noise ratio and immunity to electromagnetic interference. This interferometer will enable x-ray bang-time and fusion burn-history measurements in inertial confinement fusion with higher time resolution.

Theoretical study on time response of semiconductor photorefractive effects under subpicosecond ultra-fast X-rays

“…We conducted several experiments using GaAs at this experimental platform to study its corresponding refractive index. The experimental methods and parameters employed in this study were consistent with those outlined in [46]. Laser pulse wavelength was 1053 nm, pulsewidth was about 2 ns, and single pulse energy was about 50 J.…”

“…The theoretical model is used to interpret the X-ray detection experiments using an interferometric semiconductor X-ray detection system [46]. We conducted several experiments using GaAs at this experimental platform to study its corresponding refractive index.…”

“…We introduced the fitting method for the semiconductor response function proposed by Gao et al [46] ffalse(tfalse) =true0normale−t/τrηfalse[1−normale−ηt/τgfalse]and2emη =1−true0τgτr}where τg is the non-equilibrium carrier generating time and τr is the recombination time. By fitting the time responses of various semiconductors shown in figure 4 using equation (3.1), setting τg=200 fs, the recombination time (τr) of each material under specific X-ray incident conditions can be obtained and shown in table 1.…”

“…The time responses of different semiconductor materials are depicted in figure 4. We introduced the fitting method for the semiconductor response function proposed by Gao et al [46]…”