Our  simulation work deals with the energy calibration in orbit using cosmic-ray
 heavy ions.  In particular, we developed a simple nucleus-nucleus interaction model
 for GEANT4 benchmarked on  the nuclear-reaction patterns observed in the GSI
 experiment. This model is based on the  EPAX parametrization of isotope-production
 cross sections by Sümmerer and Blank.

An example of comparison between data and simulation results can be seen below.
The incident ion is Si at 1.7 GeV/nucleon, and what is displayed is the deposited
energy measured in the 8 CsI layers.

Data



Simulation results

 

The main peaks around E=2500 MeV correspond to non-interacting events
depositing energy in the calorimeter via ionisation only. The secondary peaks
at lower energy correspond to events where 1, 2, 3 protons are removed from
the Silicon projectile in nuclear reactions. Note that the relative amplitudes of
these peaks with respect to the main one are well reproduced by the simulations
thanks to the use of the proper cross-sections provided by EPAX.       

Another activity is devoted to preparing the analysis of calibration data obtained
on the ground with atmospheric muons.  A note describing the generation of
cystal "images"  can be found here .

EPAX , K. Sümmerer and B. Blank, Phys. Rev. C6, 034607 (2000)

Benoit Lott  02/17/2005