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Message ID: 3786     Entry time: Tue Oct 26 15:57:10 2010
Author: Jenne 
Type: Update 
Category: SUS 
Subject: One magnet broken, reglued 

[Jenne, Suresh, Thanh (Bram's Grad Student)]

When we removed the grippers from the magnets on the PRM, one of the face magnets broke off.  This time, the dumbbell remained glued to the optic, while the magnet came off.  (Usually the magnet and dumbbell will stay attached, and both come off together).  I had 3 spare magnet-dumbbells, but only one of them was the correct polarization.  The strength of the spare magnet was ~128 Gauss, while the other magnets glued to the PRM are all ~180 Gauss.  We considered this too large a discrepancy, and so elected to reuse the same magnet as before. 

We removed the dumbbell from the optic using acetone.  After the epoxy was gently removed, we drag wiped the AR face of the optic (Acetone followed by Iso, as usual), being careful to keep all the solvent away from all the other glue joints.  We cleaned off the magnet with acetone (it didn't really have any glue stuck on it...most of the glue was stuck on the dumbbell), and epoxied it to a new dumbbell. 

The PRM, as well as the magnet-dumbbell gluing fixture are in the little foil house, waiting for tomorrow's activities.  Tomorrow we will re-glue this magnet to the optic, and Thursday we will balance the optic.  

This still leaves us right on schedule for giving the PRM to Bob on Friday at lunchtime, so it can bake over the weekend.

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