Study of x-ray emission from a table top plasma focus and its application as an x-ray backlighter

Abstract

A study of a 2 kJ, 200 kA, table top plasma focus device as an intense x-ray source is reported. The x-ray yield from a number of gases, (deuterium, nitrogen, neon, argon, and xenon) is measured as a function of filling pressure and in neon as a function of anode length. In gases with Z<18, the plasma implodes to form a uniform cylindrical column, whereas for Z⩾18, the plasma consists of a number of hot spots. A maximum x-ray yield of 16.6 J and pulse length of 10–15 ns was obtained in neon. The x-ray emission was established to be due to H- and He-like line radiation. The temperature estimated from spectroscopic observations was about 300–400 eV at an electron density of (3–5)×1020 cm−3 in neon. At low pressures in neon, hard x-ray radiation, presumably due to electron beams was dominant. Mesh images of different wire materials were recorded at the optimum pressure in neon as a proof of principle for x-ray backlighting.

EBT2 dosimetry of x-rays produced by the electron beam from a Plasma Focus for medical applications

“…[3][4][5][6][7][8][9]. A most comprehensive review of the state of the art can be found in Bernard et al 10 The approach followed in the present work is to use the electron beam generated backward by the Plasma Focus device to generate xrays upon conversion of the beam onto a metal target.…”

Effect of insulator sleeve material on the x-ray emission from a plasma focus device

“…A comparison of the results shows that x-ray generation efficiency in the argon-hydrogen mixture is clearly large as compared to 0.01%-0.1% obtained by pure hydrogen 27 and the 0.001%-0.02% obtained by pure argon. 12,16,21 Kato and Be 9 using an argon-hydrogen mixture reported the x-ray generation efficiency of 1.4% from 2.8 kJ PF device. The low x-ray generation efficiency of 0.39% in our case as compared to Ref.…”

“…An important part of the recent experimental studies on x-ray and particle emission from PF is oriented in interesting applications such as contact microscopy, x-ray and electron beam lithography, generation of soft x-ray spectral lines of highly charged heavy metal ions, metal coating by ion sputtering, surface modification and deposition of thin films, x-ray backlighting, radiography of biological and mechanical objects, and micromachining. [8][9][10][11][12][13][14][15][16] The x-ray emission from a given PF device depends in a rather complicated way upon the design and operating parameters such as the operating voltage and bank energy, [17][18][19] the circuit inductance, 20 the working gas nature and pressure, 12,16,21 the anode dimensions, shape, and material, [22][23][24][25][26][27] the material and configuration of insulator sleeve, 28 and preionization assisted breakdown. 29,30 It is reported that when the plasma focus is operated in hydrogen with small admixture of inert gases, the x-ray emission is strongly enhanced.…”

Hard x-ray source for flash radiography based on a 2.5kJ plasma focus

“…Within the latter, applications such as soft x-ray imaging of biological specimens [1][2][3][4] or small samples 5 and soft x-ray lithography or micromachining [6][7][8][9][10][11] were reported. Other important results were obtained using a PF as an x-ray backlighter for photon energies of about 1 keV; 12,13 tailoring the output efficiency in the 1.2-1.3 keV window, 14 or enhancing the Cu K␣ ͑Ref. 15͒ line emission from the focus region.…”