CERN | AMS | Aerogel News
6 Software
6.2 Off-line software and data reconstruction
The geometry of the ATC counter has been included in the AMS Monte-Carlo program (version 207, released March 26, 1997). The geometry description assumes gaps of 2 mm between the blocks of aerogel as expected by the tolerances given by the manufacturer[8] (purchase order to Matsushita Electric Works Ltd., of February 11, 1997). The measured size of the aerogel blocks indicates that the tolerances are 0.5 mm on each dimension. The additional 1.5 mm gap on each dimension is going to serve as to facilitate the assembly of the module.
Figure 6-1 shows the YZ projection of the AMS detector. Visible are the magnet, the Anti-coincidence counter, the Tracker planes, the TOF, and the two layers of the ATC.
Figure 6-1 Schematic of the AMS GEANT geometry including the ATC counter.
Figure 6-2 shows the XZ projection of the AMS including the ATC. In this projection one can see the extra module n the lower layer of ATC.
Figure 6-2 XZ projection of the AMS detector as simulated by GEANT. The rightmost module in layer 2 is the special half-sized module.
Further development is under way with the inclusion of a detailed simulation of the Cerenkov photon generation and tracking package[9].
[8] The size of aerogel blocks is expected to be: 
mm3.
[9] Contact M.N.Minard
Issue: Draft - Revision: 04 - Last Modified: 20 April 1997