Study of keV radiation properties of Mo and Ti X-pinch plasma sources using a pinhole transmission grating spectrometer

Abstract

The properties of keV x-ray radiations from Mo and Ti X-pinch plasma sources at the current of 800 kA were investigated by a pinhole transmission grating spectrometer. The spectrometer was characterized by a high linear dispersion rate ͑2.9 Å/mm͒, and from its time-integrated diffraction images, rich information about the X-pinch sources ͑e.g., source number, source size, and absolute spectra͒ could be obtained. Multiple hot spots were produced in all the Mo tests with loads made of two or four 25 m wires with or without a shunt wire, and obvious increases both in the radiation intensity and in the source size around the spectral region of 2.6 keV were observed. In Ti X-pinch tests, a single keV x-ray burst with a source size of ϳ200 m and a time duration of ϳ200 ps in full width at half maximum was obtained using a load made of two 50 m wires plus a shunt wire. The intensity of x-rays decreased sharply from ϳ10 11 photon eV −1 sr −1 at 1 keV to ϳ10 8 photon eV −1 sr −1 at 4 keV. The energy-dependent source size in the band of 1-4 keV is less than 100 m and seemed to shrink quickly as x-ray energy increases.