Ferranti Plc

Gec Ferranti Defence Systems Limited

John C Parker

Hillary G Sillitto

Detector apparatus includes a dispersive prism (10) and a diffraction grating (11) of the type which produces only zero and first order diffraction patterns. Located behind the diffraction grating (11) so as to interact with the first harmonic content of the diffraction patterns is a Moire grating (12) having half the pitch of the diffraction grating (11). Detector means including at least two pairs of detectors (13-16) is located behind the Moire grating (12) to detect the presence of Moire fringes.

Detector apparatus for detecing coherent monohromatic point-source

The apparatus includes a two-coordinate array of radiation sensitive devices each operable to cause the storage of a charge proportional to the intensity and duration of radiation received. A storage element is associated with each sensitive circuit and a transfer mechanism is operable to transfer the charge from each sensitive circuit to its storage element to define a radiation image frame. A register is arranged in the same two coordinate array, and a shift mechanism operates to transfer charge from the storage elements to the register in parallel bit streams defined by one of the two coordinates. Differential detectors compare corresponding bits shifted into and out of the register and the presence of a detector output exceeding a threshold level causes the detector outputs to be sampled into an output register. The contents of the output register are shifted out serially to determine the position in the radiation image frame of each output register bit position producing a detector output.

Radiation detecting apparatus for detecting a brief radiation signal

Temperature regulation of an avalanche photodiode is obtained by internal heating, by passing a reverse current through the breakdown region of the photodiode. In operation, an empirically-derived, reverse bias potential, equal to the breakdown potential at the desired operating temperature, is applied; and when incident radiation is to be detected the reverse bias potential is temporarily lowered to an empirically-derived operating value.

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Edinburgh, United Kingdom

John C Parker