| 摘要 |
Consolidation of active and passive detectors (26, 28, 34) on a single coldfinger (20) in a dewar (10) is made possible by interposing between the detectors (26, 28, 34) an electromagnetic interference shield (64, 68) which acts as a waveguide filter blocking any interfering frequencies. The waveguide is formed by a pair of spaced interleaved shields (64, 68) one of which (64) is associated with the dewar envelope and is externally grounded, and the other of which is associated with the coldfinger (20). Photons which penetrate through the waveguide (64, 68) are deflected to the outside of the dewar (10) by a flanged narcissus shield (40) surrounding the passive detector (34). Alignment of the detectors (26, 28, 34) and assembly of the dewar (101) is greatly facilitated by constructing the envelope in several generally cylindrical sections (14, 16, 18), the lowermost one of which (14) is shorter than the coldfinger (20); and by fusing the coldfinger (20) and lowermost envelope section (14 ) to a metal mounting base (12) prior to the final assembly of the dewar (10). |
