Electron-beam-generated x rays from X pinches

Abstract

X pinches are well known to produce very small, dense plasma pinches (“micropinches”) that emit short bursts of 1.5–8keV radiation [Shelkovenko et al., Phys. Plasmas 9, 2165 (2002)]. X-ray radiation in the 8–100keV range is also emitted, only a small portion of which is associated with the micropinches. Beginning immediately after the soft x-ray burst, higher energy x-ray emission is observed that is attributed to energetic electrons accelerated in the gaps that appear in the X-pinch plasma structure. The temporal, spectral, and spatial properties of this higher energy radiation (8–100keV) have been studied using two ∼0.1μs pulsed power generators, one operating at up to 450kA peak current and the other up to 270kA. This radiation was also used for imaging in a low magnification configuration, and spatial resolution of a few tens of micrometers was demonstrated.

Hard X-rays from hybrid X pinches

“…On the other hand the hard x-ray images (Eγ>11 keV) made with an Al filter 400µm thick have very different quality. In the case of the standard X pinch, the contrast and spatial resolution of the images are very low as was typically observed with standard X pinches in the past [4,5]. In the HXP image, the mesh is clearly seen and spatial resolution is much better.…”

“…Higher energy X-ray radiation in the 8-100 keV range is also emitted [4,5]. In a standard X-pinch, beginning immediately after the soft X-ray burst, this higher energy ("hard") X-ray radiation is emitted which is attributed to energetic electrons accelerated in the gap that develops in the plasma at the X-pinch cross point immediately after the X-ray burst.…”

“…The first one lasts 1-2 ns and occurs as the gap opens up after the hot spot radiative explosion. The second hard X-ray component is associated with the completion of the gap opening up to form a "minidiode" between dense plasma electrodes, lasts more than 10 ns and has much bigger spatial dimensions [4,5]. Thus, electron beams are an inherent attribute of an X pinch because they are always present to a larger or smaller extent in all X pinch experiments, and so studies of such beams are necessary to better understand X-pinch dynamics at the time of, and immediately after the soft X-ray burst.…”

Developments of compact pulsed-power system toward X-ray sources

“…Magnetic pressure compresses the wire/plasma, and it can be further imploded by self-magnetic pressure. Radiation energy W r > 500 mJ was observed in the range 1.2-1.5 keV and W r > 20 mJ in the energy range 3-5 keV [1,2].…”

Investigation of characteristics of hard x-rays produced during implosions of wire array loads on 1.6 MA Zebra generator

“…The emission of hard x-rays (HXR) with photon energies greater than 5 keV is a common feature in Z-pinch discharges such as vacuum sparks [1][2][3], plasma focus [4,5], gas-puff [6,7], X-pinch [8][9][10][11] and wire array [12][13][14][15][16]. The previous studies showed that X-pinch had emitted HXR continuum and characteristic line radiations due to interaction of energetic electron beams with matter [11].…”