[Olympus] acceptance of MWPS lumi monitor

[Jan C. Bernauer]

Dear Stan and all,

  I just pushed the updates into olympus_release.

I'd like to use this opportunity to repeat the request of Colton that 
everybody please check the positions/sizes of the detectors in the gdml 
files, if you haven't done so already.

Best regards,

Jan


On 23.08.12 08:46, Belostotski, Stanislav wrote:
> Dear Jan and all,
> having analyzed the MC file I found out that MWPC sensitive area is
> wrongly described: the sensitive area  given in MC is 15.5x15.5cm**2
> while  it is  10.5x10.5cm**2. This results in  higher count rate
> obtained from MC using MWPC tracks. Also, electron scattering angle
> distribution is twice wider then expected.Could you (Jan)  please
> correct that by inserting 10.5x10.5cm**2.
> The latter number is good enough as taken proceeding from experimental
> hit distribution and corresponds to MWPC drawings.
> The distance from the I.P. (269cm) is correct.
> In ideal case (point like target, no secondary re-scattering, no
> magnetic field) we have
> solid angle=1.52x10**-3 sr (one arm),
> the cross section found from MC, no magnetic field,   is 6206nb/sr so we
> end up with the
> integrated cross section 6206nb/sr x 1.52x10**-3 sr = 9.43 nb
>    which is equal to the count rate at integrated luminosity of 1/nb. For
> the in bending /out bending magnetic field I have (preliminary) obtained
> 6.55nb and 11.52nb, respectively, the numbers close to that obtained by
> Axel (not forget a factor of 2 for two arms). For the final numbers we
> need to generate two MC files (magnetic field +-) with correct MWPC
> dimensions. However I believe that the above numbers are very close to
> reality.
> With best regards StanB
>
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