[Frost] A couple of things

[Bill Briscoe]

Hi Eugene,

To answer one question -- we would also be interested in the pppi- channel. 

Bill

----- Original Message -----
From: Eugene Pasyuk <pasyuk at jlab.org>
Date: Monday, June 14, 2010 3:36 am
Subject: [Frost] A couple of things
To: FROST <frost at jlab.org>

> Hi all,
> 
> There are couple of things on our hands to take care of.
> 
> The first one is Run coordination for the next two months between June 
> 
> 19 and August 13. That's 8 weeks. So far I have not heard voices of 
> volunteers except Patrick. I hope you don't expect two of us to cover 
> 
> these 8 weeks, or do you?
> 
> The second is related to the potential three week extension and 
> possibility to run with deuteron target. Volker needs written 
> justification 1-2 pages with brief description of what and why we are 
> 
> going to do during this extra time. We also should say who is going to 
> 
> analyze these data.
> We started this discussion awhile ago. It looks like we reached a 
> consensus about what we are going to do. Let me summarize.
> We will run with linearly polarized beam on transversely polarized 
> deuteron target. Since the time is limited we can run only one 
> coherent 
> edge setting. We can concentrate on the kinematical range around W=1.7 
> 
> GeV. I think it reasonable to set coherent edge probably at 1.2 GeV.
> Earlier Igor compiled and sent out some data to support this 
> particular 
> energy. We need to summarize to something half a page to a page of text.
> To run with coh_edge at 1.2 the best would be to go with 3 pass beam. 
> 
> That would be 3.36 GeV electron beam. If we go 4 pass, the end of the 
> 
> tagging range will be about 0.89 GeV a bit to close to 1.2 GeV.
> 
> We can go after three reactions.
> gn->pppi-
> gn->npi+pi-
> gn->K0Lambda
> 
> There are no doubts about feasibility of the first two. The cross 
> section is large.
> For the third one we need to get some estimates, what we can expect in 
> 
> terms of statistics and uncertainties. Franz, you did it for HDIce. 
> Could you quickly recalculate it for FROST.
> A few other things to consider for experiment configuration.
> Since all of those reaction requires at least two charged particles to 
> 
> be detected we may go with two sector trigger.
> For the 2pi reaction we would need to detect recoil neutron. It makes 
> 
> sense to turn on LAC to have better acceptance for neutrons.
> There is also question of torus field polarity. Do we want to run 
> reversed polarity (positive inbending) like g13 did or keep it as it 
> is now?
> 
> We still don't know what material we will have. Two options are being 
> 
> considered. d-butanol or d-propandiole. All depends on the 
> availability 
> of proper radical.
> d-butanol is preferable in terms of dilution factor. The figure of 
> merit 
> butanol vs. propandiole is roughly 1.2.
> As far as the degree of polarization is concerned with both materials 
> 
> people were able to get 80% polarization.
> Even though we are talking about three week extension realistically we 
> 
> may expect that we will probably have two weeks for data taking (one 
> week for conversion and set up of the target.
> 
> Manpower for analysis. The list is open. There are some ideas
> Mike Dugger (ASU) expressed interest to analyze pppi-.
> I would imagine Volker and Steffen would be interested to analyze 2pi?
> KLamda - Franz?
> Please, comment on this.
> 
> We have to prepare this justification within two weeks.
> 
> -Eugene
> 
> 
> 
> 
> 
> 
> 
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