(Cd,Mn)Te detectors for characterization of X-ray emissions generated during laser-driven fusion experiments

Abstract

We present our measurements of (Cd,Mn)Te photoconductive detectors (PCDs), intending to characterize both the temporal and spectral dependence of X-ray emissions from laser-illuminated targets during inertial confinement fusion experiments. Our Cd1−xMnxTe (x=0.05) single crystals, doped with V, were grown using a vertical Bridgman method and annealed in Cd vapor for the highest resistivity of ∼1010Ωcm. The 1-mm-long and 2.3-mm-long detectors were placed in the same housing as two 1-mm-long diamond PCDs. Each device was preceded by a Be X-ray filter with 37% X-ray transmission at the 1keV cutoff energy. Energy of the incident OMEGA laser pulses varied from 2.3 to 28kJ. Using targets of empty plastic shells, we observed two X-ray emission events separated by 1.24ns: the first event was caused by heating of the shell that created a hot corona, while the second event was an X-ray emission from the fully compressed target. Experiments with targets with steel cores enabled us to analyze the time-resolved relaxation dynamics of photo-excited carriers in the (Cd,Mn)Te crystals. According to our calculations, the (Cd,Mn)Te material can very effectively absorb X-rays with energies of up to above 100keV and the (Cd,Mn)Te PCDs are likely to complement the diamond detectors currently used in laser-confinement fusion experiments.