1. 物質厚さの考察（手始め） エネルギー損失 – 物質の Stopping power, density, thickness に依る。 – 陽電子の運動量 (10-250MeV/c の領域 ) に大きく依存 しない。 – 大体、 5MeV/cm (Al), 2.5MeV/cm (Polycarbonate) 多重散乱 – 物質の Radiation length, density, thickness に依る。 – 陽電子の運動量 (10-250MeV/c の領域 ) に大きく依存。 – 大体、 200MeV/c 陽電子で 20mrad/cm (Al), 10mrad/cm (Polycarbonate) ラフな手計算と GEANT4 が一致

2.  = 391 at 200MeV/c  =97.8 at 10MeV/c  2MeV cm 2 /g (Particle data book の Stopping power の図より ) Al density = 2.699 g/cm 3 Energy loss in Al 5.4 MeV/cm GEANT4 Energy loss through Aluminum

3.  = 391 at 200MeV/c  =97.8 at 10MeV/c  2MeV cm 2 /g (Particle data book の Stopping power の図より ) Lexan density = 1.20 g/cm 3 Energy loss in Lexan 2.4 MeV/cm Peak at 2MeV Energy loss through Polycarbonate (Lexan) GEANT4

4. X 0 = 24.01 [g/cm 2 ] / 2.699 [g/cm 3 ] x =1, p=200  0 = 20[mrad]  consistent with GEANT4 20mrad Multiple scattering through Aluminum GEANT4

5. Multiple scattering through Polycarbonate X 0 = 41.50 [g/cm 2 ] / 1.2 [g/cm 3 ] x =1, p=200  0 = 9.9[mrad]  Consistent with GEANT4 10mrad GEANT4