PROBLEM neutron_sn DIM 1 GROUPS 1 SN $1
READ_MESH reed.msh
 
MATERIAL source1       S1=50 Sigma_t1=50 Sigma_s1.1=0
MATERIAL absorber      S1=0  Sigma_t1=5  Sigma_s1.1=0
MATERIAL void          S1=0  Sigma_t1=0  Sigma_s1.1=0
MATERIAL source2       S1=1  Sigma_t1=1  Sigma_s1.1=0.9
MATERIAL reflector     S1=0  Sigma_t1=1  Sigma_s1.1=0.9

BC left  mirror
BC right vacuum

SOLVE_PROBLEM

PRINT_FUNCTION phi1