MIL-PRF-49319A(CR)
4.4.4 Crosstalk. Measurements shall be made on four (4) elements of the array. The
crosstalk shall be measured under the following conditions:
a. An element shall be irradiated by a 7.5 to 12 micrometer source having a signal 20
times greater than the noise level for the element. The image of the source shall fall
entirely within the area of the detector element.
b. The signal level of the element adjacent to and on the same ground path of the irradiated
element shall be measured. The element under test shall meet the requirements of 3.5.4.
Failure to meet the requirements of 3.5.4 shall constitute failure of this test.
4.4.5 Blackbody detectivity. Noise measurements shall be made on each element of the array
under the following conditions: The detector is cooled to 77K ±3K with LN2, 295K, ±5o K
background temperature and equivalent noise bandwidth of 9 kHz ±200 Hz with low frequency 3dB
point (high pass) no greater than 80 Hz. Using the results of these measurements, the results of the
500K blackbody responsivity measurements and the nominal detector size (see 3.12.7), the 500K
blackbody detectivity for each element of the array shall be calculated. Failure to meet the
requirements of 3.5.5 shall constitute failure of this test.
4.4.6 Detector resistance. The resistance of each element of the array shall be measured.
Failure to meet requirements of 3.5.6 shall constitute failure of this test.
4.4.7 Responsivity. Blackbody responsivity of each element of the array may be measured
with the Detector-Dewar cooled with LN2 to 77K ± 3K. Nominal element size (see 3.12.7) shall be
used in responsivity calculations and blackbody temperature shall be 500°, ±5K. Failure to meet the
requirements of 3.5.7 shall constitute failure of this test.
4.4.8 Temperature sensors. The 77K calibration point may be determined by cooling the
inner Detector-Dewar with liquid nitrogen. A 1.00 mA ±0.01 mA bias shall be applied to the sensor
diode and the voltage shall be monitored and recorded at the 77K calibration point. Failure to meet
the requirements of 3.5.8 shall constitute failure of this test.
4.4.9 Spectral response. The spectral response of the sixth element from each end of the
array or adjacent element on the high end and the higher number of the two center elements shall be
tested per "Standard Procedures for Testing Infrared Detectors and Describing Their Performance",
by R.C. Jones, D. Goodwin, and G. Pullen, dated 12 September 1960, Office of the Director of
Defense Research and Engineering. If these elements are defective, an adjacent element may be
substituted. The spectral sensitivity is defined as the 50 percent relative response points and shall
be measured on the assembled Detector-Dewar. Failure to meet requirements of the 3.5.9 shall
constitute failure of this test.
4.4.10 Detector bias. The detector bias power shall be tested per "Standard Procedures for
Testing Infrared Detectors and Describing Their Performance", by R.C. Jones, D. Goodwin, and G.
Pullen, dated 12 September 1960, Office of the Director of Defense Research and Engineering.
Failure to meet the requirements of 3.5.10 shall constitute failure of this test.
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