Re: [BLAST_SHIFTS] spin angle drifted

From: Karen Dow (kdow@mit.edu)
Date: Tue Aug 24 2004 - 14:02:40 EDT


         Brian McAllister just checked the current and voltage from the T
and L power supplies for the last week. There is essentially no change,
nothing larger than 0.5%.

         If I've done the math correctly, I think the transverse field
would need to drop by 35% to take the spin angle from 32 to 20 degrees. I
believe we'd see that in the power supply readback; also, the beam would
need to be resteered. Unless I'm missing something, I think the holding
field is still pointing at 32 degrees; the only thing that could have
changed would be the sign of one or both fields, I suppose (I didn't ask
Brian if they log the status of the holding field reversing switch).

         As Vitaliy says, having the Hall probe readback would be helpful,
but that involves opening up the target chamber, and I don't know that we
have a spare probe. So we'll probably have to keep running like this for
at least a few days.

                                         Karen

At 01:46 PM 8/24/2004 -0400, John Calarco wrote:

>This problem with the spin angle needs to be addressed at once. By
>continuing to run at the incorrect angle, we are wasting valuable
>time by running in an inefficient manner.
>
>--
>John R. Calarco
>Dept. of Physics
>Univ. of New Hampshire
>Durham, NH 03824
>phone: (603)862-2088
>FAX: (603)862-2998
>email: calarco@unh.edu



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