Table 3.

Comparison of simulated and measured lateral profiles for the large snout. E_p is the proton energy in MeV at nozzle entrance, m is the SOBP width of the SOBP in millimeters, and z is the depth of the profile relative to the upstream surface of the water phantom (isocenter) in millimeters. The absolute differences in the penumbra widths, denoted as ΔP_90–10 for the values of the 90%–10% penumbras, ΔP_90–50 for the values of the 90%–50% and ΔP_80–20 for the absolute differences in the 80%–20% penumbras, are given in millimeters. The differences in field size, ΔFS, measured from the 50% to the 50% dose location, are also given in millimeters. The maximum dose difference, ΔD_max, in the high-dose region of the profile is given in percent of the dose normalized to the center of the profile.

Ep (MeV)	m (mm)	z (mm)	ΔP90–10 (mm)	ΔP90–50 (mm)	ΔP80–20 (mm)	ΔFS (mm)	ΔDmax (%)
250	40	248	1.14	0.53	0.96	0.52	0.9
250	40	228	1.41	0.63	1	0.58	0.8
250	40	208	1.37	0.69	0.79	0.51	0.9
250	100	248	1.34	0.61	1.04	0.3	1.0
250	100	199	1.32	0.68	0.89	0.53	0.9
250	100	149	0.68	0.17	0.35	0.52	0.9
250	160	248	1.17	0.63	1.02	0.54	1.0
250	160	163	0.93	0.55	0.38	0.5	1.0
250	160	83	0.33	0.28	0.37	0.13	0.9
250	100	206	1.64	1.07	0.93	0.24	1.5
250	100	157	0.92	0.45	0.52	0.36	1.0
250	100	107	0.15	0.01	0	0.47	0.8
225	40	166	1.33	0.54	0.66	0.57	1.0
225	40	186	0.97	0.64	0.85	0.58	0.9
225	40	205	1.77	0.89	0.91	0.85	1.5
225	100	108	0.39	0.03	0.03	0.49	1.0
225	100	157	1.21	0.52	0.63	0.69	1.0
225	100	205	1.89	0.99	0.92	0.73	0.8
225	140	65	0.32	0.23	0.35	0.33	0.9
225	140	135	0.85	0.3	0.44	0.59	0.9
225	140	205	2.01	1.13	0.97	0.79	1.0
225	100	65	0.30	0.27	0.27	0.24	0.9
225	100	116	0.66	0.10	0.25	0.49	1.0
225	100	165	1.29	0.56	0.61	0.61	1.0
200	40	124	0.45	0.28	0.53	0.59	1.9
200	40	144	1.78	1.02	1.11	1.55	1.5
200	40	164	1.55	1.14	0.69	0.52	1.8
200	100	115	1.14	0.50	0.61	0.57	1.3
200	100	164	1.89	1.15	0.78	0.41	1.8
200	140	60	0.59	0.02	0.17	0.57	1.1
200	140	94	0.46	0.32	0.18	0.52	0.7
200	60	78	0.15	0.16	0.07	0.22	2.2
200	60	108	0.85	0.48	0.40	0.17	0.9
200	60	137	1.21	0.77	0.68	0.04	3.5
180	40	98	0.22	0.05	0.09	0.56	2.5
180	40	117	0.88	0.33	0.44	0.65	2.0
180	40	135	1.36	0.73	0.72	0.69	3.0
180	60	78	0.30	0.11	0.08	0.28	1.5
180	60	107	0.79	0.32	0.40	0.66	2.4
180	60	135	0.77	0.47	0.56	0.18	2.6
180	100	60	0.39	0.19	0.24	0.36	1.3
180	100	85	0.32	0.13	0.12	0.56	1.0
180	100	135	1.43	0.82	0.83	0.73	3.0
180	60	60	0.10	0.18	0.17	0.44	1.0
180	60	80	0.02	0.06	0.02	0.29	0.9
180	60	110	0.96	0.54	0.60	0.76	4.0
160	40	70	0.04	0.20	0.07	0.53	2.3
160	40	90	0.03	0.08	0.01	0.17	2.6
160	40	108	0.14	0.20	0.01	0.08	3.0
160	80	68	0.39	0.26	0.32	0.25	2.1
160	80	108	0.04	0.19	0.16	0.04	3.0
160	60	60	0.34	0.14	0.19	0.36	2.4
160	60	80	0.06	0.00	0.03	0.49	2.7
140	40	64	0.17	0.13	0.16	0.31	2.1
120	40	43	0.21	0.12	0.03	0.43	2.0
100	30	12	0.49	0.34	0.32	0.05	3.0
100	30	28	0.11	0.15	0.01	0.54	1.5