<title>High-altitude balloon flight of CdZnTe detectors for high-energy x-ray astronomy</title>

This paper presents the results of a measurement of the high-energy (E ≥ 17 keV) X-ray flux from Sco XR-1 extending to higher energies than has previously been reported. The measurement was made during a balloon flight launched from Mildura, Australia, on 29 February 1968. The X-ray observatory contained two independent X-ray detectors, one being similar in principle to the active collimator detector pioneered by Peterson et al., the other being basically similar to the graded shield detector developed by Boldt et al. Our two detecting systems are described in more detail by Buselli et al. and also in previous papers of this conference.

Download Full-text

The Detection of High-Energy X-Rays from Ara XR-1 and Nor XR-1

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000011243 ◽

1968 ◽

Vol 1 (4) ◽

pp. 165-166

Author(s):

R. M. Thomas

Keyword(s):

Zenith Angle ◽

High Energy ◽

Azimuth Angle ◽

Field Of View ◽

X Rays ◽

Balloon Flight ◽

X Ray ◽

Energy Channels

This paper presents observations of weak X-ray sources at photon energies between 20 and 100 keV which were made during a balloon flight conducted from Mildura, Australia on 29 February 1968. Results obtained from Sco XR-1 and the Sagittarius region during this flight have been presented elsewhere, and here we report additional results obtained during a search of an area of sky in which several sources have been reported from rocket experiments at photon energies below about 10 keV. The detector used was an actively collimated and shielded NaI(T1) crystal, 2 mm thick and 54.3 cm2 in area. Incident photons were sorted into 16 energy channels between 7 and 167 keV (1.76 to 0.07 Å). The collimator field of view was 8°FWHM; the telescope axis was fixed at a zenith angle of 32° and its azimuth angle was varied by rotating the observatory below the balloon. This allowed the telescope to scan back and forth in azimuth across a source, the azimuth angle at any time being indicated by magnetometers.

Download Full-text

High Energy γ-ray Observations of SN 1987A

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000022682 ◽

1988 ◽

Vol 7 (4) ◽

pp. 486-489

Author(s):

R.K. Sood ◽

J.A. Thomas ◽

L. Waldron ◽

R.K. Manchanda ◽

G.K. Rochester ◽

...

Keyword(s):

High Energy ◽

Balloon Flight ◽

X Ray ◽

Preliminary Results ◽

Sn 1987A ◽

Γ Ray

AbstractSN 1987A has been observed with a combined high energy γ-ray (50-500 MeV) and hard X-ray (15-150 keV) payload during a balloon flight on 5 April 1988 from Alice Springs, Australia. The γ-ray observations, along with our earlier ones on 19 April 1987 are the only such observations of the supernova to date. The γ-ray detector characteristics are described. The preliminary results of the recent flight and their implications in terms of the known supernova parameters are discussed.

Download Full-text

A New Radio-Wave Technique in X-Ray Astronomy

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000011966 ◽

1969 ◽

Vol 1 (6) ◽

pp. 290-291 ◽

Cited By ~ 5

Author(s):

P. J. Edwards

Keyword(s):

High Altitude ◽

Radio Wave ◽

Early History ◽

Balloon Flight ◽

X Ray ◽

New Radio ◽

Wave Technique ◽

History Of ◽

Flux Measurements ◽

Limited Duration

It is evident that the limited duration of a single rocket or balloon flight is a severe handicap to the study of variable X-ray sources like Cen XR-2, the early history of which can only be conjectured from the few available rocket observations. The whole question of the variability of X-ray sources remains in doubt because of the difficulty of relating infrequent high-altitude flux measurements of short duration made with a variety of instruments. There are obvious advantages in a method of monitoring celestial X-ray fluxes from the ground for prolonged periods of time. Such a method has recently been found and, although presently restricted to strong sources like Sco XR-1 and Cen XR-2, is capable of considerable refinement.

Download Full-text

High-purity Ge x-ray detectors: Sensitivity factors and usefulness

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136350 ◽

1990 ◽

Vol 48 (2) ◽

pp. 548-548

Author(s):

E. B. Steel

Keyword(s):

High Purity ◽

High Energy ◽

Quantitative Chemical Analysis ◽

Detector Performance ◽

X Ray ◽

Detector Sensitivity ◽

Specimen Holder ◽

Many Instruments ◽

Charge Resolution ◽

Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

Download Full-text

Designing high-resolution slow scan CCD-based TEM camera systems

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012936x ◽

1992 ◽

Vol 50 (2) ◽

pp. 946-947

Author(s):

James F. Mancuso ◽

William B. Maxwell ◽

Russell E. Camp ◽

Mark H. Ellisman

Keyword(s):

Fiber Optics ◽

Ccd Camera ◽

High Energy ◽

Phosphor Layer ◽

X Ray ◽

Light Production ◽

Camera Systems ◽

X Ray Imaging ◽

Electron Image ◽

Scintillating Fiber

The imaging requirements for 1000 line CCD camera systems include resolution, sensitivity, and field of view. In electronic camera systems these characteristics are determined primarily by the performance of the electro-optic interface. This component converts the electron image into a light image which is ultimately received by a camera sensor.Light production in the interface occurs when high energy electrons strike a phosphor or scintillator. Resolution is limited by electron scattering and absorption. For a constant resolution, more energy deposition occurs in denser phosphors (Figure 1). In this respect, high density x-ray phosphors such as Gd2O2S are better than ZnS based cathode ray tube phosphors. Scintillating fiber optics can be used instead of a discrete phosphor layer. The resolution of scintillating fiber optics that are used in x-ray imaging exceed 20 1p/mm and can be made very large. An example of a digital TEM image using a scintillating fiber optic plate is shown in Figure 2.

Download Full-text

The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117777 ◽

1985 ◽

Vol 43 ◽

pp. 154-157

Author(s):

A.J. Tousimis

Keyword(s):

Ion Beam ◽

Depth Resolution ◽

Sample Surface ◽

High Energy ◽

X Rays ◽

X Ray ◽

Electrons And Ions ◽

Spatial Depth ◽

Minimum Surface Area ◽

Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

Download Full-text

Utilisation of High-Energy Heat Sources in Magnesium Alloy Surface Layer Treatment

Archives of Metallurgy and Materials ◽

10.2478/amm-2013-0047 ◽

2013 ◽

Vol 58 (2) ◽

pp. 619-624 ◽

Cited By ~ 2

Author(s):

M. Szafarska ◽

J. Iwaszko ◽

K. Kudła ◽

I. Łegowik

Keyword(s):

Surface Layer ◽

Magnesium Alloy ◽

Physicochemical Properties ◽

Treatment Effectiveness ◽

High Energy ◽

Alloy Surface ◽

Heat Sources ◽

X Ray ◽

Additional Equipment ◽

Alloy Surface Layer

The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

Download Full-text