We (Dr. Gary Blanpied and Chase Boulware) added six counters and five blocks of iron to the simulation set up by Greg Schmid at LLNL. In the following tables, scintillators 1-5 are those already in the GEANT simulation and scintillators 6-11 are the added counters. Sandwiched in between these .5 cm scintillators we put in five blocks of iron. All pieces are centered on the beam and their z-coordinates(cm) along the beam are shown below. Taking advantage of the tighter beam spots toward the front scintillators, we graduated their sizes as shown. The dimensions given in cm are the total length of the sides of the pieces in the x,y, and then z direction, with z still along the beam.
| Detector element z-coordinate | Detector element dimensions |
|---|---|
| z(scint6)= 1000 | 20 x 20 x .5 |
| z(fe1)= 1050 | 20 x 20 x 10 |
| z(scint7)= 1069 | 20 x 20 x .5 |
| z(fe2)= 1070 | 20 x 20 x 10 |
| z(scint8)= 1089 | 20 x 20 x .5 |
| z(fe3)= 1090 | 22 x 22 x 20 |
| z(scint9)= 1119 | 22 x 22 x .5 |
| z(fe4)= 1120 | 24 x 24 x .5 |
| z(scint10)=1149 | 24 x 24 x .5 |
| z(fe5)= 1150 | 26 x 26 x 30 |
| z(scint11)=1190 | 26 x 26 x .5 |
The GEANT results for separate muon and pion beams show that this setup begins to be effective in discriminating between the two particles at scintillator 9 from 2 GeV up and at scintillator 11 from about 5 GeV up. By effectiveness we mean the setup transmits about 90% of the muon beam while letting through only about 10% of the pion beam to the scintillator being examined. This level of effectiveness allows minimal reliance on the exactness of the GEANT simulation. These results are shown below(each run consisted of 1000 particles):
From the results of this simulation we anticipate actually placing scintillators at positions 6, 9, and 11. As described, the setup works well at energies above 2 GeV.
This page revised July 9, 1998, by Chase Boulware.