1. bookVolume 60 (2015): Issue 2 (June 2015)
Journal Details
License
Format
Journal
eISSN
1508-5791
First Published
25 Mar 2014
Publication timeframe
4 times per year
Languages
English
access type Open Access

Recent measurements of soft X-ray emission from the DPF-1000U facility

Published Online: 22 Jun 2015
Volume & Issue: Volume 60 (2015) - Issue 2 (June 2015)
Page range: 303 - 308
Received: 15 Jun 2014
Accepted: 30 Jan 2015
Journal Details
License
Format
Journal
eISSN
1508-5791
First Published
25 Mar 2014
Publication timeframe
4 times per year
Languages
English
Abstract

Soft X-ray imaging is a very useful diagnostic technique in plasma-focus (PF) experiments. This paper reports results of four experimental sessions which were carried out at the DPF-1000U plasma-focus facility in 2013 and 2014. Over 200 discharges were performed at various experimental conditions. Measurements were taken using two X-ray pinhole cameras with a line of sight perpendicular to the z-axis, at different azimuthal angles (about 20° and 200°), and looking towards the centre of the PF-pinch column. They were equipped with diaphragms 1000 μm or 200–300 μm in diameter and coated with filters of 500 μm Al foil and 10 μm Be foil, respectively. Data on the neutron emission were collected with silver activation counters. For time-resolved measurements the use was made of four PIN diodes equipped with various filters and oriented towards the centre of the PF-column, in the direction perpendicular to the electrode axis. The recorded X-ray images revealed that when the additional gas-puff system is activated during the discharge, the stability of the discharge is improved. The data collected in these experiments confirmed the appearance of a filamentary fine structure in the PF discharges. In the past years the formation of such filaments was observed in many Z-pinch type experiments. Some of the recorded X-ray images have also revealed the appearance of the so-called hot-spots, i.e. small plasma regions of a very intense X-ray emission. Such a phenomenon was observed before in many PF experiments, e.g. in the MAJA-PF device, but it has not been investigated so far in a large facility such as the DPF-1000U. The time-resolved measurements provided the evidence of a time lapse between the X-ray emission from plasma regions located at different distance from the anode surface. The formation of distinct ‘hot-spots’ in different instants of the DPF-1000U discharge was also observed.

Keywords

1. Lebert, R., Neff, W., & Rothweiler, D. (1996). Pinch plasma source for X-ray microscopy with nanosecond exposure time. X-Ray Sci. Technol., 6, 107–140. DOI: 10.3233/XST-1996-6201.10.3233/XST-1996-6201Search in Google Scholar

2. Bernard, A., Bruzzone, H., Choi, P., Chuaqui, H., Gribkov, V., Herrera, J., Hirano, K., Krejci, A., Lee, S., Luo, C., Mezzetti, F., Sadowski, M. J., Schmidt, H., Ware, K., Wong, C. S., & Zoita, V. (1998). Scientific status of plasma-focus research. J. Moscow Phys. Soc., 8, 93–170.Search in Google Scholar

3. Sadowski, M., Herold, H., Schmidt, H., & Shakhatre, M. (1984). Filamentary structure of the pinch column in plas ma focus discharges. Phys. Lett. A, 105, 117–123. DOI: 10.1016/0375-9601(84)90650-9.10.1016/0375-9601(84)90650-9Search in Google Scholar

4. Scholz, M., Drozdowicz, K., Karpinski, L., Woźnicka, U., Krauz, V., Kubes, P., Paduch, M., Sadowski, M. J., Czaus, K., Malinowski, K., Kwiatkowski, R., Skladnik-Sadowska, E., & Zebrowski, J. (2013). Status of plasma-focus research in Poland. In Proceedings of International Conference PLASMA-2013, September 2–6, 2013 (T10). Warsaw, Poland. http://plasma2013.ipplm.pl/.Search in Google Scholar

5. Sadowski, M. J., & Scholz, M. (2008). The main issues of research on dense magnetised plasmas in PF discharges. Plasma Sources Sci. Techn., 17, 024001. DOI: 10.1088/0963-0252/17/2/024001.10.1088/0963-0252/17/2/024001Search in Google Scholar

6. Jakubowski, L., Sadowski, M., Baronova, E. O., & Vikhrev, V. V. (1997). Study of X-ray polarization and e-beams generated during hot-spots formation in PF-discharges. Dense Z-pinches. AIP Conf. Proc., 409, 443–447. DOI: 10.1063/1.53825.10.1063/1.53825Search in Google Scholar

Recommended articles from Trend MD

Plan your remote conference with Sciendo