[Frost] Helicity for g9b?

[Franz Klein]

Mike,
the g9a beam was direct reporting, therefore you could use TGBI.latch1 or 
HEAD.trigbits.
During g9b there was already Qweak running ... similar situation like with 
g14, except different flip frequencies, but also delayed reporting, in 
part 8 windows, in part 16 windows.
In January I started a wiki page with helicity info for g9b (access from 
meeting page), see 
http://clasweb.jlab.org/rungroups/g9/wiki/index.php/Circular_Beam_Polarization

There are still some caveats with the helicity state extraction because 
the polar crate had its own life ... I changed the routines but haven't 
tested them enough. As soon as I get out of my g14 hole, I'll finish that 
job.

Have a nice evening
Franz


On Wed, 11 Apr 2012, Michael Dugger wrote:

>
> Hi,
>
> I know this has been discussed but I can't remember the details: how do we
> get the helicity information for g9b? Is it the same type of procedure as
> for g9a:
>
> if (getbits(TGBI[0].latch1, 15,1)==1) helicity = 1;
> if (getbits(TGBI[0].latch1, 15,1)==0) helicity = -1;
>
> and then flip the sign according to run number?
>
> If so, does anyone know how the sign is changing with respect to run
> number?
>
> -Michael
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>

===============================================================
                   Franz J. Klein, Associate Professor
                   CUA, Department of Physics
                   Washington, DC 20064
   office: Hannan Hall 206          phone: 202-319-6190
   or: Jefferson Lab,CC F-243       phone: 757-269-6672
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