Preliminary measurements in Sahand plasma-focus emphasizing on the temporal characteristics of hard and soft X-rays

Abstract

Plasma Focus has been known as an intense source of soft and hard X-rays (SXR and HXR). In this system a hot and dense plasma column is formed as a result of fast discharging a high current (∼MA) in a given gas. Various radiations are emitted from the pinched plasma. The aim of this paper is to give some information about the temporal behavior of the emitted X-rays from Sahand Filippov type plasma focus device. The optimum conditions for the X-ray production are also investigated. The results show that at each discharge voltage, there is an optimum pressure in which the pinch current is maximum as well as the HXR and SXR yields in the case of argon as the working gas. The optimum pressure increases linearly with the operation voltage. Furthermore the pinch current along with the yield of X-rays increases with the operating voltage at the optimum pressure. The study of the time resolved and time integrated signals of hard and soft X-rays in neon, argon and deuterium as working gases, indicate that the small peaks in the time resolved signals of HXR can be attributed to “micro pinches” which are observed in all above mentioned three gases. Attributing the main peak to the onset of the instability in the plasma column, one can declare that the life-time of the pinch decreases with the atomic number of the gas. The full width at half maximum (FWHM) of the pulses which actually represents the radiation time is maximum for Ne and minimum for Ar.