ISSN:
1572-9508
Keywords:
instrumentation
;
X-rays
;
detectors
;
imaging telescopes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A new imaging balloon-borne telescope for hard X-rays in the energy range from 30 to 100 keV is described. The imaging capability is provided by the use of an extended URA-based coded-mask. With only one motor and suitable stop pins, we can rotate a carbon-fiber wheel with most of the mask elements attached to it by 180°, and a bar, which is also part of the mask pattern and is allowed to rotate freely over the wheel, by 90°; this combined rotation creates an antimask of the original mask, except for the central element. This is a novel and elegant manner of providing an antimask without additional weight and complex mechanical manipulations. We show that the use of antimasks is a very effective method of eliminating systematic variations in the background map over the position-sensitive detector area. The expected sensitivity of the instrument for the 30–100 keV range is of the order of 7 × 10-5 photons cm-2 s-1 keV-1, for an integration time of 104 seconds at a residual atmosphere of 3.5 g cm-2. This telescope will provide imaging observations of bright galactic hard X-ray sources with an angular resolution of ∼2° in a 10° by 10° FOV, which is defined by a collimator placed in front of the detector system. We are particularly interested in the galactic center region, where recent imaging results in X-rays have shown the presence of an interesting source field. Results of computer simulations of the imaging system are reported.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00576323
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