| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 01/17/2003 | 1749 | 01/20/2003 | 1835 | Suspect |
| Subject: | NSA/AERI/C1 - Failure of AERI cryogenic cooler |
| DataStreams: | nsaaerisummaryC1.a1, nsaaeriengineerC1.a1, nsaaerich1C1.a1, nsaaerich2C1.a1 |
| Description: | In January 2003, the cryogenic cooler current for the Barrow, AERI detector was steadily increasing. This increase is a sign of cooler failure. On January 16,2003, the cooler began to make noise. The cooler was shut-off on January 17,2003 and any condensed gases were allowed to vent. Condensed gases in the detector dewar cause a cooler to work harder and increase the current. The cooler was then resealed and turned on. However, the cooler did not recover and the current was at a maximum. The cooler was unable to completely cool the detector and the detector never achieved a temperature below 72K. Higher detector temperature increases instrument noise. The instrument was shut off on January 20, 2003 at 1835GMT to prevent a catatrophic failure due to complete cooler failure and repressurization of the detector dewar, which would result in a subsequent implosion of the dewar. |
| Suggestions: | The higher detector temperature resulted in more noise in the spectral data and a corresponding decrease in the signal-to-noise ratio. The user must evaluate if the additional noise is high enough to affect calculations. All spectral data in this time frame should be individually evaluated. Data quality prior to January 17, 2003 at 1749 GMT is not affected. |
| Measurements: | nsaaeriengineerC1.a1: more
nsaaerich1C1.a1: more nsaaerisummaryC1.a1: more nsaaerich2C1.a1: more |