skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Progress in neutron-, X-ray- and VIS spectroscopic diagnostics of large-scale plasma focus experiments at ICDMP

Abstract

Substantial progress has been made in various diagnostics for investigating results of experiments during the last years performed with the PF1000 device at IPPLM, Warsaw, Poland. In addition to standard diagnostics of the electrical characteristics of up to 1 MJ discharges in a Mather type plasma focus geometry, such as high speed photography, X-ray, fast electron beam and time-integrated neutron measurements, there have been made among others at least three quite successful efforts recently: 1) Setting up of a neutron time-of-flight line with up to five scintillation detectors including optical fibre based data collection equipment, 2) Use of a Mechelle spectrometer with CCD registration and possibility to take time-resolved spectra with resolutions down to 100 ns and 3) Setting up and using pinhole cameras equipped with solid state nuclear track detectors for the detection of fusion generated protons. Correlations of emission events as well as plasma and electrical current dynamics are investigated. Neutron emission characteristics and fusion products production mechanisms are discussed considering a generalized beam target model, called Gyrating Particle Model.

Authors:
 [1]
  1. ICDMP, 23 Hery, 00908 Warsaw (Poland)
Publication Date:
OSTI Identifier:
20797966
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 812; Journal Issue: 1; Conference: PLASMA 2005: International conference on research and applications of plasmas; 3. German-Polish conference on plasma diagnostics for fusion and applications; 5. French-Polish seminar on thermal plasma in space and laboratory, Opole-Turawa (Poland), 6-9 Sep 2005; Other Information: DOI: 10.1063/1.2168797; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CHARGE-COUPLED DEVICES; CORRELATIONS; ELECTRIC CURRENTS; ELECTRON BEAMS; NEUTRON EMISSION; NEUTRON SOURCES; NEUTRON SPECTROSCOPY; NEUTRONS; OPTICAL FIBERS; PLASMA; PLASMA DIAGNOSTICS; PLASMA FOCUS; PLASMA FOCUS DEVICES; PROTONS; SCINTILLATION COUNTERS; TIME RESOLUTION; TIME-OF-FLIGHT METHOD; X RADIATION; X-RAY SPECTROSCOPY

Citation Formats

Schmidt, Hellmut. Progress in neutron-, X-ray- and VIS spectroscopic diagnostics of large-scale plasma focus experiments at ICDMP. United States: N. p., 2006. Web. doi:10.1063/1.2168797.
Schmidt, Hellmut. Progress in neutron-, X-ray- and VIS spectroscopic diagnostics of large-scale plasma focus experiments at ICDMP. United States. doi:10.1063/1.2168797.
Schmidt, Hellmut. Sun . "Progress in neutron-, X-ray- and VIS spectroscopic diagnostics of large-scale plasma focus experiments at ICDMP". United States. doi:10.1063/1.2168797.
@article{osti_20797966,
title = {Progress in neutron-, X-ray- and VIS spectroscopic diagnostics of large-scale plasma focus experiments at ICDMP},
author = {Schmidt, Hellmut},
abstractNote = {Substantial progress has been made in various diagnostics for investigating results of experiments during the last years performed with the PF1000 device at IPPLM, Warsaw, Poland. In addition to standard diagnostics of the electrical characteristics of up to 1 MJ discharges in a Mather type plasma focus geometry, such as high speed photography, X-ray, fast electron beam and time-integrated neutron measurements, there have been made among others at least three quite successful efforts recently: 1) Setting up of a neutron time-of-flight line with up to five scintillation detectors including optical fibre based data collection equipment, 2) Use of a Mechelle spectrometer with CCD registration and possibility to take time-resolved spectra with resolutions down to 100 ns and 3) Setting up and using pinhole cameras equipped with solid state nuclear track detectors for the detection of fusion generated protons. Correlations of emission events as well as plasma and electrical current dynamics are investigated. Neutron emission characteristics and fusion products production mechanisms are discussed considering a generalized beam target model, called Gyrating Particle Model.},
doi = {10.1063/1.2168797},
journal = {AIP Conference Proceedings},
number = 1,
volume = 812,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • Results are presented from experimental studies of the correlation between X-ray and neutron emissions generated in the implosion of a deuteron plasma shell onto an Al wire. The experiments were carried out on the PF-1000 facility at currents of 1.5-1.8 MA. An Al wire 80 {mu}m in diameter and 7-9 cm in length was placed at the end of the inner electrode. During the implosion of the plasma shell, Al K-shell X-rays were first emitted at the dip of the current derivative. After the X-ray pulse, a relatively stable corona with a diameter of 2-3 mm and lifetime of amore » few hundred nanoseconds formed around the wire. The presence of the wire did not considerably reduce the total neutron yield (at most 10{sup 11} neutrons per shot) in comparison to discharges without a wire. As a rule, the intensity of neutron emission was maximal a few tens of nanoseconds after the peak of X-ray emission. A detailed comparison of two shots with low and high neutron yields have shown that the neutron yield depends on the configuration and dynamics of the discharge. The possible influence of the self-generated axial component of the magnetic field on the development of the plasma focus and the acceleration of fast deuterons is discussed.« less
  • The paper presents a summary of experimental studies of the corpuscular and X-ray emission, which were carried out with two medium-size Plasma-Focus (PF) facilities at IPJ in Swierk, Poland, during recent years. Those experiments were performed with the MAJA-PF and PF-360 devices operated within the energy range from 37 kJ to 121 kJ. The two-peak neutron emission was observed within PF-360 facility discharges. Energy of neutrons in the first pulse, as measured along the z-axis, was En = (2.65 {+-} 0.13) MeV, while that measured side-on was En = (2.47 {+-} 0.15) MeV. Electron beams were mostly generated after themore » maximum compression phase, while high-energy deuterons were generated earlier.« less
  • Experimental results are presented which verify the possibility, formerly predicted, of the self-formation of a closed, spheromak-like magnetic configuration (SLMC) in a plasma focus discharge.
  • The x-ray structure ({lambda}{lt}10 A) of the DPF-78 discharge was investigated with different heavy-gas admixtures to a basic D{sub 2} filling. A possible classification of plasma features is proposed. Micropinches with an unusual high aspect ratio of about 10:1 were found. Soft x-ray spectra of single micropinches were registered on film. The use of x-ray spectroscopic methods by means of spectra simulation codes allowed us to estimate the parameters of particular types of pinches with axial size of 0.5 mm and full radial size of 0.05 mm. In the He-like ionization state we obtained {ital n}{sub {ital e}}{approx}3{times}10{sup 21} cm{supmore » {minus}3} and {ital T}{sub {ital e}}{approx}0.8 keV. The electron temperature determined in the H-like ionization stage was considerably higher, {ital T}{sub {ital e}}{approx}2 keV, indicating a strong ionizing plasma. Possible deviations from the Bennett condition are discussed in connection with the spectroscopic results. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.« less
  • The plasma focus discharge was studied with a specially developed Cauchois spectrograph and a convex-crystal spectrograph. The presence of {approximately} 1 MeV Ta heavy ions moving toward the cathode was observed for the device geometry comprising the angle with a conical recess. In the flat anode geometry fast electron beams with E{sub e} > 60 kev energy were observed. The values of T{sub e} and N{sub e} in the dense high-temperature plasma produced during the pinch noncylindrical compression were estimated. 5 refs., 3 figs.