[Halld-physics] draft text of the eta-Primakoff proposal update

[Ashot Gasparian]

   Hi Matt,

   This is a really very healty and useful discussion for the
  proposed experiment. We will continue it, for sure, but for the next
  few days I will be out of my email box for travel.

  Thanks a lot,
  Ashot


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Ashot Gasparian                    Phone:(336)285-2112 (NC A&T)
Professor of Physics
Physics Department                       (757)-269-7914 JLab
NC A&T State University              Fax:(757)-269-6273 JLab
Greensboro, NC 27411               email: gasparan at jlab.org
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On Wed, 1 Dec 2010, Matthew Shepherd wrote:

>
> Hi Ashot,
>
> I know there has been a lot of back and forth on your update to the PAC and you are nearing the final hours before you must send your submission.  I just want to restate one thing, for clarity, so we understand each other.
>
> Both you and Liping have confirmed that you are assuming a 0.25% systematic error per photon on photons from eta -> gamma gamma that reconstructed in the FCAL.  That's 0.5% on total detection efficiency systematic error.  You need this for your 3% systematic error budget.
>
> Since we are designing and building the FCAL I want to clearly state that the FCAL has not been designed with such a requirement on precision reconstruction efficiency.  As I (and both you and Liping) have stated, there are no validated practical ideas for calibrating the efficiency so precisely.  As best I understand from you and Liping, you plan to develop a physics-based calibration method in the future.
>
> I just want to make sure understand each other -- you are assuming detector performance that exceeds our design specifications.  (I hope we are able to deliver on these performance goals, but at the moment I don't see a practical route.)
>
> Cheers,
>
> Matt
>
>