PENELOPE 2003 - OECD Nuclear Energy Agency

6.2. Examples of MAIN programs 199
E 0 = 1.25 MeV (roughly the average energy of gamma rays from 60 Co) entering a 3”×3”
NaI scintillation detector in an Al case, whose inner surface is partially covered by a layer
of Al 2 O 3 , which diffuses scintillation light back to the crystal and the photomultiplier.
In the material data file NAIAL.MAT, the order of the materials is NaI (MAT=1), Al 2 O 3
(MAT=2) and Al (MAT=3). The incident beam photons move along the z-axis with θ = 0
deg (i.e. upwards) and impinge normally on the surface of the detector. The geometry
is shown schematically in the insets of fig. 6.4, which displays two of the distributions
generated by PENCYL. The plotted distributions were obtained from 5 million random
showers; the error bars represent statistical uncertainties (3σ), which are pretty small
in this case.
• Example input file of the PENCYL code.
....+....1....+....2....+....3....+....4....+....5....+....6....+....7..
TITLE Example from the distribution package...
GSTART NaI detector with Al cover and Al2O3 reflecting foil
LAYER -0.24 -0.16 1
CENTRE 0.00 0.00
CYLIND 3 0.00 4.05
LAYER -0.16 0.00 2
CYLIND 2 0.00 3.97
CYLIND 3 3.97 4.05
LAYER 0.00 7.72 3
CYLIND 1 0.00 3.81
CYLIND 2 3.81 3.97
CYLIND 3 3.97 4.05
LAYER 7.72 9.72 4
CYLIND 3 0.00 4.05
GEND
SKPAR 2 [Primary particles: 1=electron, 2=photon, 3=positron]
SENERG 1.25E6
[Initial energy (monoenergetic sources only)]
SPOSIT 0.0 0.0 -10.0
[Coordinates of the source centre]
NMAT 3 [Number of different materials, .le.10]
SIMPAR 1 1.0E5 1000 1.0E5 0.1 0.1 1.0E4 1000 [M,EABS,C1,C2,WCC,WCR]
SIMPAR 2 1.0E5 1000 1.0E5 0.1 0.1 1.0E4 1000 [M.EABS,C1,C2,WCC,WCR]
SIMPAR 3 1.0E5 1000 1.0E5 0.1 0.1 1.0E4 1000 [M,EABS,C1,C2,WCC,WCR]
PFNAME naial.mat
[Material definition file, 18 characters]
ABSEN 1 [Tally the distr. of absorbed E in this material]
DOSE2D 3 1 50 50 [Tally 2D dose and charge distr. in this body]
RESUME lastdump.dat [Read from this dump file, 18 characters]
DUMPTO lastdump.dat
[Generate this dump file, 18 characters]
NSIMSH 1000 [Desired number of simulated showers, max=2**31-1]
TIME 300 [Allotted simulation time, in sec]
....+....1....+....2....+....3....+....4....+....5....+....6....+....7..