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Entry  Thu Nov 12 18:01:10 2009, Frank, Things to Buy, RefCav, heaters for the other two chambers 
    Reply  Thu Nov 12 20:56:38 2009, rana, Things to Buy, RefCav, heaters for the other two chambers 
       Reply  Fri Nov 13 10:56:32 2009, Frank, Things to Buy, RefCav, heaters for the other two chambers 
          Reply  Fri Nov 13 12:46:35 2009, rana, Misc, RefCav, heaters for the other two chambers 
             Reply  Tue Nov 17 12:01:54 2009, Frank, Misc, RefCav, heaters for the other two chambers 
Message ID: 13     Entry time: Tue Nov 17 12:01:54 2009     In reply to: 12
Author: Frank 
Type: Misc 
Category: RefCav 
Subject: heaters for the other two chambers 

IQuote:

For the heater, my main concern is on the residual thermal gradients after stabilization. The Alnis, Hansch, et al papers described how they had trouble with using multiple heaters and multiple sensors.

Our experience from the 40m is also that the single out of loop sensor (AD590) shows a much larger signal than the residual in-loop noise. This is only an issue below 10 mHz, so its not worth worrying about if it makes things take longer in the near term.

 

my hope is that if we choose the right heaters with the same heating power density that we will not have large thermal gradients. e.g. if we choose 4 heaters in total, 2 small ones and 2 large ones and we choose the right values for the resistance (you have the choice of 5 different values)  then e.g. we first could connect a small and a large one in series and then both pairs in parallel or so. I don't wanna have individual drivers for the individual heaters. That should give us a fairly even temperature distribution of the entire chamber.

So far our plan is also that we add 5 or more sensors on each layer of insulation/heating in order to measure the thermal distribution and gradient throughout the entire insulation system.

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