This document summarizes a student practice at JINR, Dubna in 2011. The practice involved 3 students from Czech Technical University in Prague and 1 student from University of Bucharest who aimed to understand photon production and its role in collective phenomena explanations. They sought to simulate photon spectra from high energy collisions and the energy deposition of photons in an electromagnetic calorimeter using GEANT, PYTHIA and PAW software. The calorimeter simulation showed it could detect low energy photons with small background contribution from high energy particles due to its VETO detector and ability to locate photons within 2 cm.

1. 2011
JINR, DUBNA
Student Practice

2.  Vaclav Kosar
Czech Technical University in Prague
 Viktor Burian
Czech Technical University in Prague
 Andra-Georgia Ibanescu
University of Bucharest

3. Igor Rufanov
Elena Kokoulina
Vladimir Nikitin

4.  To understand photon production and it’s
importance for collective phenomena
explanations.
 To get familiar with GEANT, PYTHIA, PAW
 To simulate the spectra of photons produced in
high energy collisions
 To understand how a electromagnetic
calorimeter works.
 To simulate the energy deposition spectra of
photons in a calorimeter.

6.  Isotropical with energy distribution:

8. - capability to measure low energy deposit
Emin < 5MeV
- the dimension of one cell
4 x 4 x 120 cm3
- localization of photon σ < 2 cm.

9. Red - BGO crystals
Blue - organic
scintillator - cutting
the charged
particles
Green - Veto -
energy leakages
From GEANT

12. 50
GeV

14.  In spite of small dimension of detector it allows
one to detect low energy photons with small
background contribution from high energy
particles.
 This is achieved due to VETO detector and
measurement of location of incoming photons.
 Signal of soft photons is detectable for cross
section of several mb, according to the
simulation.

16.  Generate total momentum of photons in CMS
 Generate the direction of photons in CMS
 Calculate the photons momentum in LS
 Calculate energy of photons in LS
)/)0(exp(0 Arandpp =
)5.0)0((*2,, −= randzyx
222
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rxppCMS /*=
)2,1()2,1( CMSLS pp = )*
*
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r
zp
p CMSLS += γ
)3()2()1( 222
LSLSLS
pppELS ++=