An experiment to measure the mass density of a plasma armature

A diagnostic technique for determining the mass density, and possibly the plasma composition, of the plasma armature in the MIDI-3 accelerator free-running arc is described. The armature primarily consists of components of polyethylene and copper, and can reach velocities in excess of 8 km/s. The approach in this proof-of-principle experiment utilizes a flash X-ray source (with X-rays energies from 3 keV to 20 keV), an elliptical X-ray crystal spectrometer, and an appropriate detector array and data acquisition system.<>