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Message ID: 337     Entry time: Wed Sep 1 15:22:39 2010
Author: tara 
Type: Notes 
Category: RefCav 
Subject: current parameters for cavities 

   Temperature on both cavities are fairly constant over -8 hrs, still can't simultaneously lock both cavities.                        

                              ACAV                      RCAV

XXX_SETPT          37.3                       35.0

XXX_TEMPAVG        37.301                 34.997

SLOWDC              -0.11645 (VCOMON center @ 0),    -0.1114

XXX_HEATER      4.72971              (FSS)1.49154

 

Since everything is stable now, I'll lock RCAV and adjust ACAV temperature to lock them together withing AOM range.

I'll change ACAV_SETPT from 37.3->37.4, to see how SLOWDC has to change to lock ACAV.

 

Wed Sep 01 21:04:24 2010

After 6 hrs, ACAV_TEMPAVG is stable around 37.4 C.

SLOWDC for ACAV is -0.1200 (VCOMON center @ 0)

 This means For ACAV, dV(slow dc) per dT(ACAV) = (0.1203-0.11645)/0.1 = 0.039 V/K.

Since RCAV is locked when SLOWDC = -0.1114, we have to decrease the temperature from 37.4 C by (0.1203 - 0.1114)/0.039 = 0.2282 K.

That is 37.4 - 0.2282 = 37.1718.

Now I set ACAV_SETPT to 37.2 C.

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