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Nanometer scale structures such as multilayers, gratings and natural crystals are playing an increasing role in spectroscopic applications for X-ray astrophysics. A few examples are briefly described as an introduction to current and planned applications pursued at the Danish Space Research Institute in collaboration with the FOM Institute for Plasma Physics, Nieuwegein, the Max-Planck-Institut fur Extratemestrische Physik, Aussenstelle Berlin, the Space Research Institute, Russian Academy of Sciences, the Smithsonian Astrophysical Observatory, Ovonics Synthetic Materials Company and Lawrence Livermore National Laboratory

XMM is a third generation X-ray astronomy mission in which the artificial boundary between astronomy and astrophysics disappears. This long lived orbiting observatory brings sensitivity improvements of > 102 over existing missions (EINSTEIN, EXOSAT, ROSAT). It will be capable of finding and studying in detail either the furthest quasars and active galactic nuclei at the edge of the Universe or detecting the coronal emission from the faintest stars within the Galaxy. It is a multi-purpose high-throughput facility (2.4 m2 collecting power at 1 keV) consisting of two arrays of grazing incidence Wolter type 1 telescopes. The first, consisting of 20 telescopes (10 arcsec. on-axis resolution, 1° field of view and energy range up to 5 keV) will be more sensitive than AXAF for the rapid study of many classes of objects. The second array with 7 telescopes (30 arcsec. on-axis resolution, 0.5° field of view but an energy range extending to 10 keV with > 5 × 103 cm2 at 7 keV) will perform tests for spectral evolution in distant active galactic nuclei and studies of line emission with high sensitivity for a wide variety of sources. Both of them will perform spatially resolved high resolution spectroscopy of supernova remnants and clusters of galaxies. An assessment study of this mission is starting in ESA in January 1983.

X-80 is one of the five missions being studied by ESA and a candidate for selection. The scientific aims and the main characteristics of the model payload will be discussed.

Intravenous injection of acrylonitrile (ACN) causes adrenal hemorrhagic necrosis. ACN and its metabolites react with glutathione and bind covalently with macromolecules. Hence the purpose of this investigation was to measure the distribution and covalent binding of radiolabel derived from [1-14C]ACN in order to determine whether binding of ACN or its metabolites may be implicated in the pathogenesis of ACN-induced adrenal injury. Following intravenous injections of ACN, concentrations of total radiolabel were highest in the blood, liver, duodenum, kidneys, and adrenals. Except for blood, there was a time-dependent decrease in total radiolabel in these tissues. Compared with other major organ systems, the levels of covalently bound radiolabel were lower in the adrenal glands. These results do not support a role of covalent binding of ACN or its metabolites in the adrenal toxicity of ACN, but suggest that the initial high concentrations of total radiolabelled compounds derived from ACN could play a role in the action of ACN on the adrenal glands.

High-resolution spectra of Fe xxv have been observed from Princeton Large Torus tokamak discharges and are used for a detailed comparison with theoretical predictions of Bely-Dubau, Gabriel, and Volont\'e for the ($1{s}^{2}nl\ensuremath{-}1s2pnl$, $ng~3$) dielectronic satellites at 1.85 \AA{}. The theory predicts a significant apparent broadening of the resonance lines of high-$Z$ heliumlike ions in high-temperature plasmas due to the dielectronic capture of electrons into outer atomic shells. The experimental results and theoretical predictions are in good general agreement.

The influence of diet on the acute toxicity (lethality) and distribution of glutathione as measured by tissue nonprotein sulfhydryl (NPSH) concentration following acrylonitrile (ACN) treatment was studied. The tissue distribution of radiolabeled (14C) acrylonitrile or its radioactive metabolites was also determined. The diets tested were a standard laboratory rat chow; a casein-based, complete diet; and 2 diets high in saturated fat content that were either lipotrope deficient or lipotrope supplemented. The latter 2 diets were associated with decreased weight gain in the absence of ACN and increased lethality after orally administratered ACN. The increase in lethality, while most pronounced in the group fed the lipotrope-deficient, high-fat diet, was also seen in rats fed the purified control diet. The high-fat diets were associated with increases in brain and liver NPSH concentrations (mg NPSH/100 g body weight). Following oral administration of 1–14C-ACN, blood contained the highest specific activity. In terms of fraction of administered dose, liver was found to contain the highest total fraction. In the tissues measured, a majority of radioactivity appeared bound to trichloroacetic acid (TCA) insoluble components. The sequence of tissue activity (nCi 14C per g or ml) was as follows: blood > stomach > liver, duodenum, lung, kidney > brain > adrenal. While diet affected toxicity, it did not modify this general ranking.

Temporally and spatially resolved profiles of the PDX soft x‐ray spectra have been measured during single tokamak pulses of circular divertor plasmas with a recently developed pulse‐height analyzer. This detection system incorporates an array of five vertically displaced sets of lithium‐drifted silicon detectors, each consisting of three independent channels optimized for rapid data collection in adjacent energy regions. Simultaneous measurements of x‐ray emission integrated along five chords of the plasma cross section can, thereby, be achieved. Abel inversion of these data yields temporally resolved radial profiles of the local electron temperature from the slope of the continuum, concentrations of high‐Z impurities from the characteristic line intensities, and a measure of Zeff from the continuum intensity. The techniques of x‐ray pulse‐height analysis, with illustrations featuring the results from the initial PDX circular plasma experiments, are discussed in detail. In addition, comparisons between ci...

Acrylonitrile-induced adrenal necrosis is associated with the early depletion of adrenal glutathione and elevation of adrenal dopamine. These biochemical events could result in increased susceptibility to free radical-mediated lipid peroxidation which may play a role in the pathogenesis of adrenal injury caused by acrylonitrile. In the studies reported here we found no elevation in malonaldehyde or conjugated diene concentrations of adrenal glands (or of glandular stomach and duodenal mucosa which may be other targets of acrylonitrile action) from rats given acrylonitrile. Conjugated diene concentrations in liver microsomes were significantly elevated (132%) 60 min after administration of carbon tetrachloride or 15 (38%), 30 (58%), and 60 (46%) min after injection of acrylonitrile whereas mitochondrial conjugated diene concentrations were not significantly altered by acrylonitrile. Our results suggest that while lipid peroxidation may not be involved in the pathogenesis of acrylonitrile adrenal injury it may occur in other tissues after acrylonitrile administration.

The OSO-8 satellite contains a focusing mosaic graphite crystal X-ray polarimeter that is oriented along the spin axis of the wheel section of the satellite. The polarimeter operates at 2.6 and 5.2 keV. Polarization in a source appears as a modulation of the counting rate at twice the satellite spin frequency. The amplitude and phase of the modulation are simply related to the polarization and position angle, respectively. Two independent polarimeters are employed, and their axes are offset by 128°. Focusing is achieved by mounting the crystals on a parabolic sector, which reduces the background without reducing the sensitivity. The low background that results from the focusing not only improves the statistical quality of the data but also substantially reduces the danger that an asymmetry in the charged particle background may produce a spurious polarization result. This is particularly important in the case of weak sources. The instrument has been described in detail elsewhere (Novick 1975); here we will briefly discuss the results obtained on the Crab Nebula, Cyg X-1, and Cyg X-2.

A versatile X-ray spectrometer/scatterometer for the study of X-ray optical elements such as grazing incidence mirrors, crystals and X-ray gratings has been built and put into operation at the Danish Space Research Institute. The spectrometer is built on a 1.5 m long granite bench with the X-ray source located at one end of the bench where it can be rotated around a fixed vertical axis. The beam defining elements are perfect crystals of Si, Ge or Quartz. With these it is possible to define a highly collimated beam of a few arcsec FWHM in the scattering plane. Examples of measurements on various X-ray optical elements are presented. In particular, a study of intrinsic and mosaic diffraction from test crystals is presented in detail. The deconvolution of the experimental data is discussed in general terms and as an example the results of a calculation of the spectrometer resolution function for the four crystal set-up employed in the above mentioned crystal study are presented.

A single dose of acrylonitrile can produce fatal adrenal apoplexy within approximately 2 h. Our previous studies also indicate that multiple injections of the chemical cause acute hemorrhagic and occasional nonperforating duodenal ulcers. Other authors have reported increase in gut and lung neoplasia after chronic exposure. The present study was designed to elucidate the subacute and chronic actions of acrylonitrile on the adrenals, stomach and duodenum by correlating biochemical, functional and morphologic investigations, as well as to gain insight into the mechanisms of action of acrylonitrile. Rats were exposed to 0, 0.0001% (1 ppm), 0.002%, 0.01%, 0.05% or 0.2% acrylonitrile in drinking water, or to the same amount of the chemical given through daily gavage, for 7, 21 or 60 days. Acrylonitrile caused a time- and dose-dependent decrease in plasma corticosterone levels; aldosterone was affected only by the 'high' dose and prolonged time of exposure. Young rats were more susceptible than adults to this action of acrylonitrile. The adrenal cortex, especially the zona fasciculata, was atrophic in rats that had ingested the nitrile through drinking water. At 0.05% and 0.2%, it also caused decreased food intake and body weight gain. The adrenals were enlarged with a hyperplastic zona fasciculata after daily doses of a bolus of acrylonitrile. Ingestion of the chemical did not interfere with compensatory enlargement of the adrenal gland following unilateral adrenalectomy. On the other hand, the ACTH-induced elevation of corticosterone plasma concentration was significantly attenuated by acrylonitrile in drinking water. Electron microscopy of the adrenal glands revealed no consistent changes in the steroid-producing cells. We thus postulate that accelerated turnover of circulating corticoids and/or interference with the secretion or action of ACTH may primarily be responsible for the decreased plasma levels of corticosterone and aldosterone in rats that ingest acrylonitrile. The mucosa in the stomach at the junction of the forestomach and glandular region of animals that had ingested acrylonitrile was hyperplastic. The corpus also showed regional mucosal hyperplasia with the appearance of 'cobble-stoning'. These changes were preceded and associated with an elevated concentration of non-protein sulfhydryls mostly in the mucosa of the glandular stomach. A similar, less prominent elevation also occurred in the proximal duodenum. These alterations may resemble the preneoplastic combination of elevated glutathione and focal hyperplasia described in the liver with hepatocarcinogens.(ABSTRACT TRUNCATED AT 400 WORDS)

In order to investigate structure-activity relationships that influence metabolism of nitriles to CN-, thiocyanate was measured, as an index of CN- release, in urine of rats given equimolar doses of nitriles. Significantly more SCN- was excreted after po than after ip administration of saturated (C2-C5) nitriles, but SCN- excretion was the same after both routes for n-hexanenitrile. Among saturated nitriles, SCN- excretion was maximal for the C3 and C4 compounds, propionitrile, n-butyronitrile, and isobutyronitrile, after both po and ip administration. SCN- excretion was not elevated after administration of the tertiary nitrile trimethylacetonitrile. Administration (po) of the unsaturated nitriles acrylonitrile, crotonitrile, and 3-butenenitrile yielded 37%, 5.6%, and 29% of the dose as SCN-, whereas after ip injection 4.5%, 4.6%, and 18% of the doses were excreted as SCN-, respectively. After iv injection of acrylonitrile, urinary SCN- content was not elevated, whereas 45% of an iv dose of the saturated analog propionitrile was excreted as SCN-. These results suggest that length of the carbon chain, presence of substituents at the alpha-carbon, position of double bonds, and, for some compounds, route of administration, are important factors influencing the release of CN- from nitriles.

A measurement of Sco X-1 with the graphite-crystal polarimeters on the OSO 8 satellite yields upper limits (3 sigmas) to the linear polarization of 2.7% and 4.9% at 2.6 keV and 5.2 keV, respectively. The results are discussed in terms of an accretion-disk model.

We describe the x‐ray diagnostics employed on the Tandem Mirror Experiment‐Upgrade (TMX‐U) to measure the x‐ray emission from plasma locations where electron cyclotron radio frequency heating is applied. At each potential minimum of the TMX‐U plasma, broadband spectra are obtained with NaI scintillation and cooled HPGe detectors that are coaligned to view the same plasma volume. The high‐energy sensitivity of the NaI detector is necessary for studying x rays emitted by hot runaway electrons with energies exceeding 200 keV. The spectral response of the HPGe detector complements the NaI performance. Its higher resolution at energies below 100 keV is the key to determining what fraction of ECRH power is transferred to a bulk density of cooler (∼50 keV) mirror‐confined electrons. X‐ray spectra from the TMX‐U end cell, where a potential peak produced by sloshing ions and ECRH create a localized plasma with Te ∼1.6 keV, will be measured with a Si(Li) detector. The geometrical configuration, shielding requiremen...

Results of a search for X-ray polarization in the Crab pulsar are presented which were obtained by observing the pulsar at 2.6 and 5.2 keV with identical X-ray polarimeters aboard OSO 8. The polarization in different portions of the X-ray light curve is analyzed, the polarization contribution due to the nebula is removed, and the results of the analysis are given for isolated portions of both the primary pulse and the interpulse at 2.6 and 5.2 keV. No evidence for X-ray polarization is found at the 99% confidence level; 3-sigma upper limits to the polarization at 2.6 keV are given along with the largest polarization allowed at 5.2 keV by the 99% confidence counter. It is noted that the trailing edge of the interpulse at 2.6 keV is 26% polarized at the 92% confidence level, while the 5.2-keV polarization measurement of 40% in the leading edge of the primary pulse is different from zero at 96% confidence. X-ray and optical polarization measurements are compared.

Current research efforts in magnetic fusion strongly depend upon information gained from x‐ray observations of the confined plasma. Spectroscopic measurements make it possible to determine plasma temperature, density, electron energy distribution, ionization state, impurity content, and plasma velocity. X‐ray imaging provides estimates of the spatial distribution of a few of these parameters, facilitates temporal studies of plasma size and shape, and indicates MHD activity. Diagnosing plasma properties in tokamaks and tandem mirrors has resulted in the development of a variety of sophisticated spectroscopy and imaging instrumentation. All share standard x‐ray detection techniques and are either dispersive or nondispersive devices. To achieve optimal performance, these systems are individually tailored to specific operating regimes. Criteria such as energy, temporal and spatial resolution, plasma lifetime, x‐ray emission bandwidth, system throughput, and the effects of the non‐x‐ray background influence th...

We report the results of X-ray emission measurements made at various plasma locations in the Tandem Mirror Experiment-Upgrade (TMX-U). By manipulating the electron and ion density profiles within the magnetic mirror end cells, a local minimum in the axial electrostatic potential creates a barrier that thermally isolates central cell electrons from those in the end cells. This thermal barrier makes it possible to heat end cell electrons to a temperature (~1.6 keV) that is significantly higher than the central cell value (30 to 200 eV), thereby increasing the ion confining potential. Formation of this potential peak is attributable, in part, to mirror-trapped hot ions (8 keV) that are injected as beams of neutral particles. The resulting ion density profile exhibits two symmetric peaks at the locations of the ion turning points and a depression where the magnetic field is a minimum. Electron cyclotron resonance heating (ECRH) is applied at the density minimum and produces a population of hot, mirror-trapped electrons (20 to 200 keV). It reduces an already depressed electrostatic potential to establish the thermal barrier. In addition, ECRH applied at the outer density peak raises the -ion confining potential and enhances central cell ion confinement by increasing the end cell electron temperature. X-ray measurements are made with solid state and scintillation detectors at the ECRH locations. Medium resolution spectra are obtained over a broad energy band and have proven to be an important tool for determining the efficiency of thermal barrier formation. We present our initial findings from these non-Maxwellian plasmas.

We want to image the hot, mirror‐confined electrons produced by electron cyclotron resonant heating in the end cells of the Tandem Mirror Experiment‐Upgrade. Preliminary spectroscopic measurements with NaI(Tl) detectors indicate tail electron temperatures in the range of 100–300 keV. Our goal is to image x‐rays in the energy range 10–200 keV, for plasma densities as low as 1011 cm−3. A spatial resolution of one part in forty at framing rates of 200 Hz should be achieved. The imaging system will consist of an x‐ray converter (phosphor or scintillator) and image intensifier (diode or microchannel plate), followed by a video readout (silicon intensifier tube). We will outline the steps we are taking to implement this system.

The linear X-ray polarization of the Crab Nebula has been precisely measured at 2.6 keV and 5.2 keV with the OSO 8 graphite crystal polarimeters. The 1.4 ms time resolution of these instruments permitted the removal of any contribution to the polarization from the pulsar. The nebular polarization is 19.2% plus or minus 1.0% at a position angle of 156.4 plus or minus 1.4 deg at 2.6 keV. At 5.2 keV the corresponding results are 19.5% plus or minus 2.8% at 152.6 plus or minus 4.0 deg.