Soft X-ray Spectrograph Research Articles

Simple soft x-ray spectrograph with a multilayer mirror for plasma diagnostics

A simple soft x-ray spectrograph with a multilayer mirror has been constructed and applied for the diagnostics of a magnetically confined large plasma, which combines wavelength dispersion and x-ray imaging. Spectrophotographs of plasma radiation in the wavelength region from about 20 to 100 Å have been obtained with low-wavelength resolution. A comparison between the measured x-ray spectra and a calculation for bremsstrahlung x rays, in which the total reflection component as well as the Bragg reflection from the multilayer is taken into account, demonstrates that the spectrograph can be used to measure the electron temperature of plasmas.

SOFT X-RAY IMAGES OF THE SOLAR CORONA USING NORMAL INCIDENCE OPTICS

A solar coronal loop system has been photographed in soft X-rays using a normal incidence telescope based on multilayer mirror technology. The telescope consisted of a spherical objective rnirror of 4 cm aperture and 1 m focal length, a film cassette, and a focal plane shutter. A metallized thin plastic film filter was used to exclude visible light. The objective mirror was covered with a multilayer coating consisting of alternating layers of tungsten and carbon whose combined thicknesses satisfied the Bragg diffraction condition for 44 A... radiation The image was recorded during a rocket flight on 1985 October 25, and was dominated by emission lines arising from the Si XII spectrum. The rocket also carried a high resolution soft X-ray spectrograph that confirmed the presence of Si XII line radiation in the source. This image represents the first successful use of multilayer technology for astrophysical observations.

Soft X-Ray Images of the Solar Corona Using Normal Incidence Optics

AbstractA solar coronal loop system has been photographed in soft X-rays using a normal incidence telescope based on multilayer mirror technology. The telescope consisted of a spherical objective mirror of 4 cm aperture and 1 m focal length, a film cassette, and a focal plane shutter. A metallized thin plastic film filter was used to exclude visible light. The objective mirror was covered with a multilayer coating consisting of alternating layers of tungsten and carbon whose combined thicknesses satisfied the Bragg diffraction condition for 44 Å radiation. The image was recorded during a rocket flight on 1985 October 25, and was dominated by emission lines arising from the Si XII spectrum. The rocket also carried a high resolution soft X-ray spectrograph that confirmed the presence of Si XII line radiation in the source. This image represents the first successful use of multilayer technology for astrophysical observations.

On the possibility of detecting very hot gas through absorption-line studies

The possibility of detecting hot (T greater than or approximately equal to 10 to the 6th K) diffuse interstellar and intergalactic gas through absorption-line studies is assessed. Optical studies of semiforbidden lines are shown to be just beyond feasibility. X-ray absorption-line studies are concluded to be within the capability of future soft X-ray spectrographs, however. In particular, it is shown that the Bragg crystal spectrometer aboard Einstein could possibly have been used to detect O VII and O VIII lines against the Crab if they are present at plausible levels. Improvement of instrument parameters by only a small factor could make this the most important method available for studying hot interstellar, galactic halo and possibly even intergalactic gas.

Soft X-ray spectroscopy using an electron multiplier

The modification to a soft X-ray spectrograph in order to use an electron multiplier instead of a photographic plate is described. The instrument has been calibrated with the aluminium and magnesium L23 spectra.