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The research in high resolution solar X-ray astronomy is reported. The payload for the Aerobee 150 launch vehicle, which included a 23 cm diameter mirror whose polished surface was a nickel-phosphorus alloy is discussed along with the high resolution measurements, by Flight 13.028 CS, of the temperature and density structure of the lower corona. Flight 13.029 CS is also discussed.
The Spacelab Wolter type I X-ray telescope, which is intended for both astronomical observations and the functional verification of the future Large Area Modular Array of Reflectors (LAMAR) concept, comprises five mirrors and is designed to have a blur circle radius of 20 arcsec, with effective areas of (1) 400 sq cm at 0.25 keV, (2) 200 sq cm in the 0.5-2.0 keV range, and (3) 50 sq cm between 2 and 5 keV. A rotary interchange mechanism allows either of two imaging proportional counters to be placed at the telescope focus. The telescope's primary objective is the observational study of galactic and extragalactic X-ray sources, extending the work of the Einstein Observatory to fainter sources and higher energies. Secondarily, the costs and performance to be expected from the use of this telescope type in the LAMAR mission will be assessed.
The High Energy Astronomy Observatory - Mission B (HEAO-B), an earth orbiting X-ray telescope facility capable of locating and imaging celestial X-ray sources within one second of arc in the celestial sphere, is considered. The Focal Plane Transport Assembly (FPTA) is one of the basic structural elements of the three thousand pound HEAO-B experiment payload. The FPTA is a multifunctional assembly which supports seven imaging X-ray detectors circumferentially about a central shaft and accurately positions any particular one into the focus of a high resolution mirror assembly. A drive system, position sensor, rotary coupler, and detent alignment system, all an integral part of the rotatable portion which in turn is supported by main bearings to the stationary focal plane housing are described.
Experiments are reported in which electron beams were injected into the magnetosphere (with up to 40 kev energy and at current up to 0.8 A) to diagnose the plasma processes at great distance by measurements made in the ionosphere. In some of the experiments, the conjugate region atmosphere was used to detect the electron beam; in others, conjugate echoes were detected near the injection region. The echoes were found to respond to changes in the convection fields and to reflect auroral zone activity. Theoretical and experimental echo patterns are discussed. Evidence for beam pitch angle scattering and altered mirror heights is presented. The use of the atmospheric response to electron beams in the loss cone as a detector has been achieved using optical, X-ray, and radar techniques.
Alternative concepts are proposed for the design and fabrication of Kirkpartick-Baez nested crossed plate reflectors applicable to a high throughput, moderate resolution X-ray facility composed of a Large Area Modular Array of Reflectors (LAMAR). Numerical, structural and optical analyses are used to quantify the performance characteristics of the concepts proposed. It is found that the theoretical performance of certain concepts approaches the 0.2-min resolution of a perfect parabola of translation. The instrument under consideration has about 1000 sq cm of effective area, or five times greater area than that of the Einstein Observatory.
The feasibility of building and operating a grazing incidence X-ray telescope for auroral zone studies from the Polar Plasma Laboratory (PPL) is discussed. A detailed structural analysis of the preferred design, an array of seven nested Wolter mirrors, is presented. An engineering evaluation of the requirements for the instrumental configuration, power, weight and telemetry is included. The problems of radiation hardening and thermal control are discussed. The resulting strawman instrument is presented.
Results of an analytical study of the large orbital X-ray telescope (LOXT) are presented. The LOXT consists of a nested array of four conventional paraboloidal-hyperboloidal X-ray telescopes arranged with a common optical axis and a common focal plane. The composite nested array has a nominal effective focal length of 135.0 inches. The equations of the various mirror surfaces and the numerical values of the parameters in the defining equations are given in the technical specification sheets for the LOXT.
It is shown that by using the conical diffraction mount, existing echelle gratings can be used at grazing incidence to achieve high spectral resolution in the extreme UV and soft X rays. Design considerations for grazing incidence echelle spectrographs are examined, and two sample designs are discussed. The first, for use in the extreme UV, has a primary mirror and an entrance slit to the spectrograph. The system has a resolution of 10,000, operates at any wavelength longward of 100 A, and covers 30% of the spectrum at a single setting. The X-ray spectrograph uses objective gratings to obtain spectral resolution of 28,000 over any factor of 2 in. wavelength. It operates to wavelengths as short as 4 A.
A method is proposed for optimizing the on-axis resolution of a Kirkpatrick-Baez reflecting element. The proposed procedure provides a way to determine the location of each of the 11,200 support points (175 different points plus repeats) by using a computer-assisted structural-optical software package. This automated procedure will make it possible to determine the optical characteristics of an entire telescope module consisting of seventy mirrors.
The energization process of magnetic pumping, a combination of time dependent magnetic mirror fields with pitch-angle scattering, is applied to trapped charged particles drifting in corotating, azimuthally nonsymmetric neutron star magnetospheres. When particle energization is balanced by synchrotron radiation loss, it is found that protons, rather than electrons, reach considerable kinetic energies and radiate, in the X-ray regime, at rates up to the 10 to the 6th power MeV/proton/sec.
High resolution soft X-ray imaging from the solar probe is justified in terms of the expected scientific returns which include the determination of the temperature and density structure of a coronal loop. The advantages of the grazing incidence telescope over the multiple pinhole camera are discussed. An instrument package is described which includes a grazing incidence mirror, a thermal prefilter, a three position filter wheel and a focal plane detector baselined as an 800 by 800 back-illuminated charge coupled device. The structural assembly together with the data processing equipment would draw heavily on the designs being developed for the Solar Polar Mission.
An echelle spectrograph is described which is specifically designed for use on a 52-in. f/7.6 telescope as an instrument optimally suited for studying spectra of the faint optical counterparts to X-ray stars at moderate spectral resolution. The spectrograph is also able to accomodate a two-dimensional photon-tagging panoramic image detector so that high-time-resolution studies of the spectra of variable stars can be carried out. The equations for echelle spectrographs are summarized, and some features of the present instrument are discussed. These include its prism cross-disperser, small elliptical flat mirror, and unusually high efficiency. An iron-argon calibration spectrum obtained by pressing the film against the output fiber optics of a three-stage electrostatically focused image intensifier, a spectrum of P Cygni taken by placing the film directly in the image plane of the spectrograph, and a photon-counted image of a small section of an echellogram produced during an observation of the Ring nebula in Lyra are provided to illustrate the performance of the instrument.
Rocket studies of the low-energy X-ray sky conducted so far suffer from serious experimental problems. Therefore, an apparatus was design ed to overcome the outstanding experimental problems. The instrument developed was successfully flown in an Aerobee-170 rocket. The new device utilizes a grazing incidence paraboloid as an energy concentrator and low-pass filter. The effective bandpass of the instrument from 100 to 280 eV is determined by the combination of the counter window transmission and the mirror reflectivity.
The current state of the mechanics of the Constance II experiment, the physics results gathered, the motivation background, and future plans for the Constance II experiment are reviewed. Several improvements have been made and several experimental investigations have been completed. These include the construction/installation/testing of: (1) liquid-nitrogen cooled, Ioffe bars installed, (2) a diverter coil (3) the 100 kW ICRF generator, (4) the data acquisition system, and (5) the optimum hot-iron operation of the machine with Titanium and pulsed-gas plasma guns. Measurements were made of the density, temperature, and radius of the plasma. Ion-cyclotron fluctuations were observed, their bandwidth measured, and data collected demonstrating resonance heating. New X-ray diagnostics were designed and purchased, and progress on the Thomson scattering was made. Finally, a new hot cathode gun was designed and constructed.
A history of the events leading to the development and flight of the Einstein Observatory is given. The advantages of using grazing-incidence telescopes for solar and extrasolar X-ray astronomy is first discussed and followed by a description of the HEAO program. The Einstein Observatory marks a departure from the manner in which X-ray investigations are carried out, from individual experiments to the shared use of large facilities. The Observatory has achieved a sensitivity to point sources of 10 to the -14th erg/sq cm-sec in the 1-3 keV band, a flux 500 times smaller than previously detected and about 10 million times smaller than that of the first extrasolar source detected in 1962. The design philosophy of the Observatory entails three principles: (1) the unified scientific approach, (2) the establishment of spacecraft requirements at lowest acceptable levels that still allow operating flexibility, and (3) the idea of 'soft' rather than 'hard' failure. The mirror design, including the high resolution imager, the imaging proportional counter, and the solid-state and focal plane crystal spectrometers, is also given. An account of the struggle to gain acceptance by the scientific community and the funding agencies of the need for the Einstein Observatory mission is discussed. Finally, results of observations made by the Observatory are presented in detail, along with plans for future observation experiments.
Grazing incidence telescopes for X ray astronomy, describing mirrors, detection systems and dispersion techniques
A ray trace analysis of the vignetting characteristics of the S-056 X ray telescope is presented. The relative energy is calculated in the spot formed in the focal plane of the S-056 X ray telescope by an off axis point source at infinity for off axis angles of 0, 1, 2, ..., 35 arc minutes. At each off axis angle, the relative energies are evaluated using theoretical X ray reflectivity curves for wavelengths of 8.34 A, 17.57 A, and 27.39 A, and also using an experimental X ray reflectivity curve for 8.34 A. The effects of vignetting due purely to the geometry of the S-056 optical system are evaluated separately, as well as jointly with the effects of mirror reflectivity.
The construction of a high resolution imaging telescope experiment payload suitable for launch on an Astrobee F sounding rocket was proposed. Also integration, launch, and subsequent data analysis effort were included. The payload utilizes major component subassemblies from the HEAO-B satellite program which were nonflight development units for that program. These were the X ray mirror and high resolution imager brassboard detector. The properties of the mirror and detector were discussed. The availability of these items for a sounding rocket experiment were explored with the HEAO-B project office.