Creation of a single-shot micrometer-size X-ray source in X-pinch discharge energized by very fast capacitor bank

Summary form only given. Among dense discharge plasmas, X-pinches are well known for providing a point-like X-ray source in the keV region and have been applied for backlighting of dense plasmas. An X-pinch is commonly energized by a fast HV generator terminated by a pulse forming line, because capacitor bank based generators are slow and fail to produce a unique X-ray peak. We have used an original approach with the fast and compact generator PIAF, a low impedance machine (0.12 Ohm) based on a 1 kJ capacitor bank and an extremely low inductance design (16 nH). It is then possible to drive a 250 kA current peaking in less than 200 ns into a six nH inductive load. We will report on experimental study of X-ray source radiated from the high energy density plasma created at the crossing point of two or four wires (Mo, W) of thin diameter (18 to 25 micrometers). We used multi-filtered pinhole imaging and large aperture penumbral analysis to get time-integrated information in the 1-5 keV region. In some configurations, a unique source is observed with size as small as 10 micrometers. Using vacuum X-ray diodes and p-i-n photo-detectors, we are able to identify a single peak during less than 1.5 ns. One estimates a radiation yield of about 250-500 mJ in the softer range (<700 eV) and 50-100 mJ in the harder one (>1 keV). Preliminary results of time-integrated spectroscopy will be discussed too.