Re: muSC question, and mustop issues

[Brendan Kiburg <kiburg@npl.uiuc.edu>]

Dear Tom,
  Originally we used a 500 micron muSC and investigated the
scattering
with it and two muPCs.  Eventually Volodya replaced some of the inner
foils of the muPC and we used a single muPC with the muSC.  Later in the
run, I wrapped a 250 micron muSC with thin aluminized mylar (2x20
microns?) to try to reduce the scattering and increase the central
stopping fraction.  The thinner muSC produces
lower photostatistics and thus lower separation between
noise-electrons-muons.  For run 9 we decided to go with the 500 micron
muSC again, primarily because it produced a better(more separable) signal
without changing the scattering much.

Hope this is useful,
Brendan


On Tue, 21 Mar 2006, Tom Banks wrote:

> 
> Dear Peter et al.,
> 
> first, a question about the Run8 muSC replacement which was performed
> midway into the run: Does anyone remember the specs on the old and new
> scintillators?  I found some documentation suggesting that the original
> muSC was 500 microns thick, but I couldn't dig up anything in the ELOG
> about its replacement.  Was the primary motivation for the muSC
> replacement to further reduce the material budget in the beam and thus
> improve the stopping fraction?  Or was it more of a question of improving
> the muSC detection efficiency?
> 
> Secondly, the more I ponder the issue of muon scatters, the more concerned
> I become... We discussed it here in Berkeley and decided that this issue
> probably merits an entry in the systematics table, although it's difficult
> to see how to go about quantifying the problem.  Furthermore, we don't see
> any evidence of scatters in Bernhard's GEANT MC data.  If it's possible,
> I'd like to have a telephone discussion on the subject sometime soon,
> before people get wrapped up in Run9.
> 
> Tom
>