> Dear Djamel,
the specification sheet of the phototube should contain the
quantum efficency versus wavelength. As for reflection and absorbtion by
mirrors etc Hubert van Hecke of LANL is an expert on this. He worked a lot
on simulating aerogel cerenkovs and has some interactive tools for estimating
the efficency of an optical system.
As a first step however you might try to simulate the data by hand. Take
"golden events" where you know that you have one and only one pion hitting
C1 and plots the number of hits versus momentum. This should tell you
the effective number of photo electrons produced for good tracks. Since
these pions will be hitting C1 at almost 90 degrees you will have a pretty
good
idea of the path length. You can also use such events to estimate the amount
of
noice in C1. You could then try to add such noise to your simulation. Note
that even
if you had a perfect simulation of the the physics of C1 you would still need
to add
some electronic noise.
Yours Michael
> Hi,
>
> Does anyone of you know where I could get some details about C1
> (detailed description, tests already made, etc) ?
> I would like to simulate the respons of C1 after the passage of a
> charged particle. The scheme I have in mind is:
>
> ---------------------
> photon creation along
> particle path in gaz (Np = C*L*(1 - 1/(beta2*n2))
> ---------------------
> |
> (here L is the effective particle path since there are some scatterings
> and absorption, C is a constant)
> need to know n (index of refraction for C4H10 at 1atm)
> need to know effective absorption length in these conditions
> |
> |
> photons are emitted in a cone of opening angle theta = acos(1/(beta*n))
> |
> |
> ---------|-----------
> reflexion of photons
> hitting the mirrors
> ---------------------
> absortion?? side effects??
> |
> |
> |
> ----------------------------
> generation of photoelectrons
> in PMT from incoming photons
> converting respons in ADC
> ---------------------------
> need to know quantum efficiency
> need to know efficiency for collecting light (hopefully high!)
> which wave length range the PMT is sensitive to
>
> This looks rather simple but needs a very good knowledge of the physics of
> C1. It could be also a start for RICH respons simulation.
>
> A lot of help is needed.
>
> Thanks.
>
> Djamel
>
> --
> Djamel Ouerdane ------------------------------------------o
> | Niels Bohr Intstitute | Home: |
> | Blegdamsvej 17, DK-2100 Ø | Jagtvej 141 2D, |
> | Fax: +45 35 32 50 16 | DK-2200 Copenhagen N |
> | Tel: +45 35 32 52 69 | +45 35 86 19 74 |
> | http://www.nbi.dk/~ouerdane |
> | ouerdane@nbi.dk |
> o---------------------------------------------------------o
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