- Conference date: 19-22 April 2004
- Location: Santa Fe, New Mexico (USA)
Charge state distributions (CSDs) have been determined in low density (≈1012 cm−3) gold plasmas having either a monoenergetic beam (E Beam = 2.66, 3.53 and 4.54 keV) or experimentally simulated thermal electron distributions (T e = 2.0, 2.5 and 3.0 keV). These plasmas were created in the Livermore electron beam ion traps EBIT‐I and EBIT‐II. Line emission and radiative recombination features of Ni to Kr‐like gold ions were recorded in the x‐ray region with a crystal spectrometer and a photometrically calibrated microcalorimeter. The CSDs in the experimentally simulated thermal plasmas were inferred by fitting the observed 4f→3d and 5f→3d lines with synthetic spectra from the Hebrew University Lawrence Livermore Atomic Code (HULLAC). Additionally, the CSDs in the beam plasmas were inferred both from fitting the line emission and fitting the radiative recombination emission to calculations from the General Relativistic Atomic Structure Program (GRASP). Despite the relatively simple atomic physics in the low density plasma, differences existed between the experimental CSDs and the simulations from several available codes (e.g. RIGEL). Our experimental CSD relied upon accurate electron impact cross sections provided by HULLAC. To determine their reliability, we have experimentally determined the cross sections for several of the n=3→4 and n=3→5 excitations in Ni to Ga‐like Au and compared them to distorted wave calculations. Recent Au spectra recorded during experiments at the HELEN laser facility are presented and compared with those from EBIT‐I and EBIT‐II.
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