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Entry  Sun Feb 24 01:16:26 2013, tara, DailyProgress, RefCav, refcav and mount assembly photo(9).JPGphoto(8).JPG
    Reply  Mon Feb 25 01:02:58 2013, tara, DailyProgress, Vacuum, Heater for refcav heater.pngphoto(10).JPG
       Reply  Wed Feb 27 09:57:33 2013, tara, DailyProgress, TempCtrl, Heater for refcav 
          Reply  Thu Feb 28 09:12:22 2013, not tara, DailyProgress, TempCtrl, Heater for refcav 
             Reply  Wed Mar 6 15:44:26 2013, Zach, DailyProgress, TempCtrl, Heater for refcav 
Message ID: 1105     Entry time: Wed Feb 27 09:57:33 2013     In reply to: 1104     Reply to this: 1107
Author: tara 
Type: DailyProgress 
Category: TempCtrl 
Subject: Heater for refcav 

I'm contemplating about how to drive the heater of the copper shields. So here is a list of what happening.

Objective: to drive the heater with ~ 1W power (see the previous entry). The estimated power is from my calculation. I have not taken heat conduction/uncertainties of surface emissivity into account, we might need more power to be on the safe side.

Problem: If we use a low noise driver (using AD797, cf PSL:765), the maximum delivered power will be only~0.5 W.

So, do we need the low noise driver? or do we need to have enough power? If we just need enough power, we can drive the heater with a commercial power supply.

At this point, I think it is more important to be able to tune the cavity length with larger range so that we can see the beat. Thus, sufficient heating power should be our top priority . Better heater/ control can be developed next, once we see the beat.

So the plan is:

  1. Wrap both shields up with heating wire. The length of the wire (total resistance) depends on the limiting current/voltage available from a power supply to ensure ~2W power.
  2. Put the cavity back and bring the laser to the cavities.
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