Shock Temperature Measurement Using Neutron Resonance Spectroscopy

We report a direct measurement of temperature in a shocked metal using Doppler broadening of neutron resonances. The 21.1-eV resonance in ${}^{182}\mathrm{W}$ was used to measure the temperature in molybdenum shocked to $\sim 63\mathrm{G}\mathrm{P}\mathrm{a}$. An explosively launched aluminum flyer produced a planar shock in a molybdenum target that contained a 1-mm thick layer doped with $1.7\mathrm{a}\mathrm{t}.\%{}^{182}\mathrm{W}$. A single neutron pulse, containing resonant neutrons of less than $1\mu \mathrm{s}$ duration, probed the shocked material. Fits to the neutron time-of-flight data were used to determine the temperature of the shocked molybdenum.

Figure 1

(a) A schematic of the launcher-target assembly. (b) A magnified view of the portion with the aluminum flyer and the target.

Figure 2

(a) Static (upper) and dynamic (lower) TOF spectra for shocked molybdenum. (b) Expanded view of data with fits (red and green curves) to the data. The horizontal scale for both (a) and (b) is time in microseconds.

Figure 3

Comparison of NRS measured shock temperature in molybdenum with a theoretical calculation based on Mo-2984 tables in the SESAME EOS library [18].