Alfa  refrigerator fails 18apr06


     One of alfa's refrigerators (it has 2) failed on 18apr06 around 19:00 ast (a change over from generator to commercial power took place at 19:00).The 20K stage dewar temperature warmed up to about 50K (by 1am 19apr06). At 11 am 19apr06 the electronics turned the faulty fridge off. The 20K stage dewar temperature then dropped down to 20K around 12:00 19apr06. The 70 K stage has warmed up from 80K to about 120 K.

    To check the system temperature after the refrigerator failed, the cal was fired on/off for 240 seconds  on 19apr06 at 15:00. The a2010 data from 18apr06 and 19apr06 was also looked at to see what had happened to Tsys.
    The plots shows alfa tsys for 18apr06 and 19apr06 (.ps) (.pdf):


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