Grazing-incidence measurements of L-shell line emission from highly charged Fe in the soft x-ray region

Abstract

Line emission from highly charged ions in the soft x-ray region represents an important diagnostic for high-temperature plasmas. The wavelength region of 10–30 Å is occupied by lines from the K-shell transitions in N through Ne and L-shell transitions in Ti through Ni. Crystal spectrometers have previously been used to investigate Fe line radiation under well controlled conditions using the LLNL electron beam ion trap facility in this wavelength region. To complement this work we have instituted a grazing-incidence spectrometer with a variable line-spaced, concave grating and a flat field of focus which is suited for a multichannel detector. Simultaneous observations of the Ne-like Fe16+ n=3→2 transitions were made with this instrument and a flat-crystal spectrometer in order to establish the linear polarization of the Fe XVII lines. We present a description of the grating spectrometer and discuss its performance in comparison with Rowland circle based grazing incidence instruments.

Emission‐Line Spectra of Svii–Sxivin the 20–75 A Wavelength Region

“…By systematically recording spectra at different energies and observing the rise and relative decline of different charge states, however, it is possible to determine which emission lines belong to which charge state. Spectra were measured on EBIT-II with a grazing-incidence spectrometer ( Utter et al 1999) employing an average 2400 line mm À1 flat-field grating developed by Harada & Kita (1980) and Nakano et al (1984) with a 1.3 angle of incidence, and an instrumental resolution of $300 (at 25 8) to $500 (at 50 8). Readouts were taken with a back-illuminated, liquid nitrogen-cooled CCD camera with a 1 inch square array of 1024 ; 1024 pixels.…”

Grazing-incidence spectrometer for soft x-ray and extreme ultraviolet spectroscopy on the National Spherical Torus Experiment

“…The new Livermore-NSTX extreme ultraviolet spectrometer (LINES) is similar to that employed earlier at the Livermore electron beam ion trap facility [17]. It employs a variable line spacing grating mounted on a rotary table (average line spacing of 2400 /mm [18]).…”

Rapid, absolute calibration of x-ray filters employed by laser-produced plasma diagnostics

“…Many spectrometers are available for this task, including high purity germanium solid state detectors, high-resolution grazing incidence spectrometers [7,8], and high resolution crystal spectrometers [9,10]. Depending on the particular X-ray energy being used, one or several of these may be in operation during a measurement.…”