mat:Water/rho:1.0     1.000000E+00    2
h:1     1.119149E+01    1
o:16     8.880851E+01    8

mat:Air/rho:0.001205     1.205000E-03    4
c     1.240000E-02    6
n     7.552680E+01    7
o     2.317810E+01    8
ar     1.282700E+00    18

mat:Lead/rho:11.35     1.135000E+01    1
pb     1.000000E+02    82

# void material
mat_void 0.0 1
he 1 2
