[Dsg-halla_ecal] update

[Donald Jones]

Hi Mark, Bogdan,
I just got word from Marc that the control program was set to read the crystal temperatures as type-J thermocouples, where all the thermocouples I installed were type K. I am not sure what this will mean in actual temperatures but I tried to figure out an estimate. From online resources, it appears that type J has 33% high voltage output per degree. A 9.7mV output for a type J is 180 degC where 9.7mV for type K is 239 degC. So the crystals might have actually been well over the operating temperatures we wanted. I think that the light guides were also read out as type-J which would mean they were also reading out low which is not good news. Fortunately, the thermocouples on the front plates that are read out by the controls were correctly read as type-K thermocouples so we were not exceeding 300 degC which is the safe limit for this design.
Anyway, we will have to see, but I think there is reason for optimism that we will see better results next time especially with another air conditioner.
-Don


Donald Jones
Hall A/C Staff Scientist
Jefferson Lab
Newport News, VA
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