GEANT Simulations

E159/E160/E161 Collaboration Meeting

Feb. 10, 2001

Piotr Decowski

GEANT simulations of the spectrometer design are in progress. They are addressing the following questions:

Figures 1 and 2 show GEANT calculations of passage of muons through different materials. The advantage of the Al2O3 versus Al as a stopping material is clearly seen in reduction of moun range in Al2O3 by ~ 50% without a significant increase of the multiple scattering angle.

Figs. 1 and 2: FWHM multiple scattering angles and ranges of muons in different materials

The importance of muon multiple scattering in the filter is demonstrated in figure 3. It shows correlations between the radial distances R (in cm) from the beam axis of positive and negative muons resulting from the decay of 30 GeV J/Psi beam, at the location of a hodoscope placed 4 m away from the target, without and with the hadron filter (in these calculations, to preserve the radial symmetry, the magnetic field was turned off). The Al2O3 filter, 2 m long, is positioned directly behind the target.

Fig.3: Correlations between positive and negative mouns radii without hadron filter (left panel) and with hadron filter (right panel).