-- StevenWhite - 2013-02-28 An ongoing issue is the stability of the integrated noise calibration module,ICM. Occasionally the values are not loaded properly, a firmware/software issue. Of greater concern is the drift presumably with temperature of the device noise characteristics. It appears as if this is a temperature problem, but could be associated with the bias voltage drift from the control cards inside the dewar. There is evidence to believe that the device characteristics change with large temperature changes at the 15K stages when the refrigerator seals begin to wear. When the cryogenic temperatures are stable, the variation over from December 16, 2012 to February 27, 2013 was less than 4%.

• CryogenicTemp15KJan2013.eps:

• Plots of noise cal variations taken a few days apart normalized to beam 1. Not sure what epoch these were taken.

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