Technical Paper
Thermally Driven Acoustic Oscillations in the NICMOS Dewar Cooling Line
1997-07-01
972474
The Near Infrared Camera and Multi Object Spectrometer (NICMOS) was installed aboard the Hubble Space Telescope in February 1997. This instrument contains a solid nitrogen dewar for cooling infrared detectors to a temperature of 58 K. Gaseous helium flowing through a small diameter tube internal to the cryogen tank was used to freeze the nitrogen. A sudden and significant increase in the dewar heat leak during instrument development resulted in a detailed study of the possible causes. This investigation lead to the conclusion that thermally driven acoustic oscillations caused the anomalous heat transfer.