Simulation of the ALTEA experiment on the International Space Station with the Geant 3.21 program

The ALTEA (Anomalous Long Term Effects in Astronauts) project is aimed at the study of the transient and long term effects of cosmic particles on the astronauts' cerebral functions. The detector will fly on the International Space Station in 2005. Due to the complexity of the detector (12 double silicon detector boxes arranged around the head of the astronaut) it is necessary to have a detailed simulation of the apparatus response to cosmic ray nuclei in order to assess the detector response and its observational capabilities. The ALTEA detector was therefore simulated by using the Geant 3.21 program, by the astronauts' head described by 64 cubes of water. By using Creme96 program to evaluate the cosmic rays fluxes within the International Space Station we obtained the events distribution and the energy lost in the cubes of water, as well as the expected interaction rates. Furthermore, we calculated the triggered events number per unit of time in the detector. The simulation was also used to develop a technique to recognize the cosmic rays nuclei.