RE: Primex beam requirement

[Alexander Somov <somov@jlab.org>]

Dear Liping,

I have a couple of questions relatet to your table:

1. Photon flux stability: 1 %
  Why do you need such a precision ? You tag each beam photon
  in the energy range of interest, so that you know exactly what
  the beam flux is, i.e. you know the luminosity (regardless
  whether the beam flux is stable or not).

   ( If you use a reference channel for the Xsection measurement,
   like Compton scattering, than, of course, the flux stability
   is important)

2. Photon intensity on target: 6.4 10^6 phot/sec/GeV
   Is it in the 'signal' region 10.5 - 11.7 GeV ?


3. (Beam) energy resolution: 10-3
  Where did this number come from ?
  Is the eta production Xsection such a steap function of energy ?
  (we are talking about inclusive X section  measurements, aren't we)

Thanks,
       Sascha




On Thu, 4 Dec 2008, Gan, Liping wrote:

> Dear Richard,
>
> According our discussion at the meeting, here is updated beam requirement for PrimEx experiment.
>
> Best regards,
>
> Liping
>
>
>