Table 3.
Comparison of the predicted (simulated) and observed (measured) absorbed dose perturbations caused by stainless steel spheres listed in the leftmost column. The values listed include the air gap (G) between the Lucite plate holding the spheres and the measuring plane, and measured and predicted dose enhancements (+ΔD) and reductions (−ΔD) behind the steel spheres, and the difference between the percentage predicted and observed dose perturbations. The beam range was 161 mm for all 12 cases here.
| +ΔD [%] | −ΔD [%] | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Sphere Label |
G [cm] |
Meas. | Pred. (MCNPX) |
Pred. (Geant4) |
Pred. (FDC) |
Meas. | Pred. (MCNPX) |
Pred. (Geant 4) |
Pred. (FDC) |
||
| Old MCS |
New MCS |
Old MCS |
New MCS |
||||||||
| SS-1 | 2.0 | 11.6 | 20.8 | 7.9 | 20.7 | 11.2 | −7.7 | −19.3 | −6.7 | −5.0 | −3.0 |
| SS-1 | 15.0 | 11.8 | 12.3 | 14.1 | 11.8 | 24.6 | −68.6 | −69.3 | −68.4 | −51.4 | −54.7 |
| SS-1 | 30.0 | 7.2 | 7.9 | 4.3 | 11.1 | 7.3 | −71.2 | −49.4 | −63.4 | −45.1 | −45.6 |
| SS-1 | 63.0 | 1.2 | 5.5 | 0.3 | 2.8 | 9.8 | −36.9 | −20.0 | −28.4 | −18.4 | −19.0 |
| SS-2 | 2.0 | 15.9 | 30.3 | 17.5 | 30.0 | 14.3 | −5.0 | −14.5 | −9.6 | −2.4 | −1.5 |
| SS-2 | 15.0 | 21.5 | 19.6 | 20.5 | 20.1 | 16.0 | −62.0 | −64.8 | −64.1 | −56.5 | −55.2 |
| SS-2 | 30.0 | 18.1 | 10.5 | 8.8 | 12.6 | 14.6 | −79.1 | −70.3 | −76.7 | −62.6 | −59.3 |
| SS-2 | 63.0 | 6.6 | 2.0 | 1.0 | 8.7 | 4.6 | −59.0 | −37.9 | −41.0 | −33.1 | −32.9 |
| SS-3 | 2.0 | 30.9 | 41.6 | 19.6 | 37.9 | 24.4 | −5.9 | −10.4 | −12.0 | −3.7 | −0.5 |
| SS-3 | 15.0 | 28.4 | 22.2 | 25.4 | 20.1 | 16.0 | −53.9 | −60.7 | −58.0 | −56.5 | −55.2 |
| SS-3 | 30.0 | 16.4 | 10.1 | 12.3 | 14.0 | 15.3 | −79.7 | −82.0 | −79.1 | −71.5 | −71.5 |
| SS-3 | 63.0 | 3.4 | 1.2 | 1.4 | 1.0 | 1.9 | −85.0 | −69.4 | −79.7 | −67.2 | −64.2 |