[Halld-tagger] Polarimeter in Hall D

[Richard Jones]

Beamline working group,

To better accommodate our coleagues connecting from the Southwest, let's start this Monday's meeting at 11:30 EST. I will post an agenda on the wiki shortly.

http://www.jlab.org/Hall-D/software/wiki/index.php/Tagged_Beam_Group_Biweekly_Meetings

-Richard Jones



On 7/22/2011 7:50 PM, Barry Ritchie wrote:
> Responding to the time question, 8:30 is certainly more workable for us. 
>
> If that can start for this coming Monday's meeting, great. But if not, just let us know.
>
> ---BGR
>
>
> Professor Barry G. Ritchie
> Department of Physics
> Arizona State University
> Tempe, AZ　 85287-1504
>
> Telephone: (480) 965-4707
> Fax: (480) 965-7954
>
>
>
> -----Original Message-----
> From: Richard Jones [mailto:richard.t.jones at uconn.edu] 
> Sent: Sunday, July 17, 2011 10:19 AM
> To: Barry Ritchie
> Cc: cmeyer at ernest.phys.cmu.edu; dugger at jlab.org
> Subject: Re: Polarimeter in Hall D
>
> Barry,
>
> This is very valuable experience you are reporting, regarding the challenges of relying on spectral shape analysis alone to extract the tagged photon polarization. I think everyone in the collaboration agrees that knowing the polarization with good certainty is important. In the past there has been a perception that it will be easy to get a systematic precision at the 1-2% level using spectral shape analysis. What I am getting from your experience is that one cannot take this for granted.
>
> Asking around the working group, there is agreement that we can easily move the meeting to start at 11:30. If we move the start much later, there will be weeks when many of us miss lunch altogether -- the last meeting lasted 11:00-1:00. The meetings do not usually last 2 hours, but with the recent network problems at Jlab, starting a meeting can be laborious. Hopefully, by next week we will be back to normal operations. Does the 11:30 start time make it a little more workable for you?
>
> -Richard J.
>
> On 7/17/2011 12:17 PM, Curtis A. Meyer wrote:
>> Hi Barry -
>>
>>   I am assuming that Richard will have responded already, but the next tagger meeting will be on July 25. Richard is also trying to shift the meeting a bit later
>> in the day. The schedule of meetings can be found on the gluex wiki, which
>> just came back.
>>
>>    wiki.gluex.org
>>
>> Then goto "Meetings".
>>
>>   I have also been hearing about the challenges Ken has been having with g8,
>> so any input on this would be most welcome.
>>
>>    Curtis
>> On 7/15/11 4:23 PM, Barry Ritchie wrote:
>> Richard, will the standing Glue-X Beamline meeting be held Monday? I can’t access the schedule yet at JLab due to their Internet issues.
>>
>> I’m hoping to attend on Monday if the meeting occurs. Since Arizona stays on Standard Time year round, the 11 AM EDT time is a bit awkward for us (it’s 8 AM here). If the meeting can be moved closer to noon, that would work better for us here.
>>
>> Mike and I have been batting around some polarimetry ideas for Hall D, again motivated by the ongoing problems we’ve seen in g8. While Ken Livingston has provided us his best estimates based on peak shape fitting, we’ve pretty much demonstrated here at ASU that, regardless of how well the shape is fit, we’re seeing inconsistencies (some as high as perhaps 20%) when comparing with different coherent edge settings. Since the edge is in near-constant motion, there are multiple solutions to the shape to be fit, and one needs additional information to sort out those solutions. We’re hopeful here at ASU that the additional information we can get from edge vs. edge comparisons will help refine the estimates. It’s approaching 3 years after the experiment and we’re still working on figuring out what the polarization was!
>>
>> ---BGR
>>

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