[Fews] 50 liter Dewar down for repair

[Steve Christo]

The sniffer system has been off line as of 4/17 due to a loss of liquid 
nitrogen for cooling the IR spectrometer detector. The 50 liter Dewar 
has started losing LN2 at the rate of about 50 liters/3 days, mostly 
from evaporation caused by faulty insulation and leaking at the joints. 
The manufacturer of the Dewar, Taylor-Wharton, does not sell the pump 
out valve to their customers but they will refurbish their Dewars. Dave 
Kashy has suggested that we install our own valve if possible. The Dewar 
has been removed to the Physics Storage Building for inspection.
Steve