Hadamard transform X-ray telescope.
Abstract
A Hadamard transform X-ray telescope is a type of Dicke's random hole X-ray camera for observing the X-ray sky. Instead of making a random hole pattern mask, a cyclic Hadamard matrix or PN sequence is used to make the mask pattern of this telescope. With this mask and a position sensitive X-ray detector, Hadamard transformed image data of the X-ray sky may be obtained, and the X-ray sky image from the observed data may be easily reconstructed. The Hadamard matrix can be used to make one dimensional X-ray telescopes as well as two dimensional telescopes. When spurious counts of the detector are predominant over image counts and diffuse background counts, the signal-to-noise ratio advantage of this telescope is the square root of N over 2 compared to the slat-type X-ray telescope of the same angular resolution, where N is the number of position-sensitive detector cells and N + 1 is the order of the cyclic Hadamard matrix employed to make this mask.
- Publication:
-
Space Science Instrumentation
- Pub Date:
- December 1977
- Bibcode:
- 1977SSI.....3..473M
- Keywords:
-
- Signal To Noise Ratios;
- Transformations (Mathematics);
- X Ray Imagery;
- X Ray Telescopes;
- Cosmic Rays;
- Masking;
- Matrices (Mathematics);
- X Ray Sources;
- Astronomy;
- Telescopes:X Rays