GB903549A - Infrared radiation detector - Google Patents

Abstract

903,549. Radiation detector mountings. HUGHES AIRCRAFT CO. Dec. 6, 1960 [Dec. 22, 1959], No. 42018/60. Class 40 (3). [Also in Group XXXVI] An infra-red radiation detector mounting comprises a vacuum flask having an inner and an outer jacket which define a vacuum chamber in which is disposed the detector, a filter, and an opaque shield, which together restrict the bandwidth and direction of radiation incident upon the detector, the inner jacket forming a reservoir for a cooling medium. An infra-red photo-conductive detector cell 11 is mounted on the end wall 14 of a tubular inner jacket 13 which, together with an outer tubular jacket 17, define the evacuated space 15 of a vacuum flask, said flask forming a reservoir 20 for a cooling medium such as liquid nitrogen. A lens 19 focuses the signal radiation through a window 18 and a wavelength limiting filter 26 on to the cell, the window forming an end wall of the tube 17 and the filter 26 being attached to a tubular opaque shield 10 disposed around the cell and tightly fitted to the tube 13. The jackets 13 and 17 are sealed at their common end remote from the cell, two electrodes 21 and 22 connected to the cell being introduced through the seal. The shield 10 and filter 26 are, together with the cell 11, in good thermal contact with the cooling reservoir 20 and this is stated to be advantageous if the filter is of the absorbing kind. An interference type filter may additionally be used situated either side of the window 18. The tubular jackets may be of metal or silvered glass, and alternative arrangements of the shield 10 and filter 26 are described.