Filippov type plasma focus as intense source of hard X-rays (Ex≃50 keV)

This paper evaluates the use of a plasma focus machine (Filippov type) as a pulsed intense source of hard X-rays. It is shown experimentally that discharging a capacitor bank of W=50 kJ in the new arrangement of the discharge parameters, one can deliver into the test cavity (volume of 6*10³ cm³) an average of Φ _x=8*10^-4 J/cm². The delivered energy fluence varies in the range of 2*10^-4 J/cm²⩽Φ_x⩽2.9*10^-3 J/cm², depending on the probe position. The X-ray energy spectra were established by the differential absorption method using thermo-luminescent detectors (time-integrated spectra) or plastic scintillators (time-resolved spectra). The average energy of X-ray photons is 40 keV<E_x^av<50 keV (20 keV⩽E _x⩽170 keV) and remains quasi-constant during the main part of the pulse (~40 ns). The electron energy that can produce such bremsstrahlung radiation is in the range of 95 keV⩽E_e⩽170 keV. However, time-resolved experiments reveal that at each instant of time only one energy of electron beam occurs. The aforementioned radiation characteristics reveal new potentials for the plasma-focus machine for a variety of applications. Some insight into the physics behind production mechanism of quasi-monoenergetic relativistic-electron beams will be concurrently reviewed