UA, herein referred to as the Detector-Dewar.

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MIL-PRF-49446B(CR)

shall be used in responsivity calculations and blackbody temperature shall be 500�, �5oK.

Failure to meet requirements of 3.5.7 shall constitute failure of this test.

4.5.8 Temperature sensors. The 77o K calibration point may be determined by cooling

the inner 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 77o K calibration point. Failure to

meet requirements of 3.5.8 shall constitute failure of this test.

4.5.9 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

3.5.9 shall constitute failure of this test.

4.5.10 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 requirements of 3.5.10 shall constitute failure of this test.

4.5.11 Dewar warm and cold shields. During in-process inspection, the warm and cold

shield shall be measured to ensure conformance with the requirement Alignment of the cold

shield relative to detector elements shall be checked 100 percent during in-process inspection.

Failure to meet requirements of 3.5.11 shall constitute failure of this test.

4.5.12 Heat load. The heat load of the Detector-Dewar shall be determined with all

detectors operating at specified bias. The heat load of the Detector-Dewar shall be determined by

partially filling the Dewar's inner stem with liquid nitrogen and monitoring the rate of loss of the

cryogen. The heat load shall be calculated from the average or integrated loss rate of the cryogen

for the last 5 minutes of the Dewar's hold-time. For calculations, cooling produced by the

nitrogen phase change only shall be considered as total useful energy. If this test is performed

with the detector array unbiased, the results of this test shall be added to the results of the

detector bias power test to determine the heat load. Failure to meet requirements of 3.5.12 shall

constitute failure of this test.

4.5.13 Vacuum integrity. Vacuum integrity shall be determined on a basis of heat load

capacity. Heat load shall be measured on the unbiased Detector-Dewar. The temperature of the

Detector-Dewar shall then be elevated to +71�C for a period of 72 hours. At the completion of

the temperature exposure and stabilization at ambient temperature, the heat load shall be

measured again. Getters may not be fired during this test. Failure of the Detector-Dewar to meet

the requirements of 3.5.12 (heat load) or a 15 percent, or greater, increase in heat load between

the measurement before and after temperature exposure shall constitute failure of this test.