Filippov type plasma focus as intense source of hard x-rays (E{sub x} {approx_equal} 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{times}10{sup 3} cm{sub 3}) an average of {Phi}{sub x} = 8{times}10{sup {minus}4} J/cm{sup 2}. The delivered energy fluence varies in the range of 2{times}10{sup {minus}4} J/cm{sup 2} {le} {Phi}{sub x} {le} 2.9{times}10{sup {minus}3} J/cm{sup 2}, 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{sub x}{sup av} < 50 keV (20 keV {le} E{sub x} {le} 170 keV) and remains quasi-constant during the main part of the pulse ({approximately}40 ns). The electron energy that can produce such bremsstrahlung radiation is in the range of 95 keV {le} E{sub e} {le} 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 amore » variety of applications. Some insight into the physics behind production mechanism of quasi-monoenergetic relativistic-electron beams will be concurrently reviewed.« less