      REAL A_AIR(3), Z_AIR(3), W_AIR(3), RHO_AIR
      REAL A_CH(2),  Z_CH(2),  W_CH(2), W_CH2(2), RHO_CH
      REAL A_ROCK(4), Z_ROCK(4), W_ROCK(4), RHO_ROCK 
      REAL A_WASH(2), Z_WASH(2), W_WASH(2), RHO_WASH
      REAL A_WATER(2), Z_WATER(2), W_WATER(2), RHO_WATER
      REAL A_CS, Z_CS, RHO_CS, RADL_CS, ABSL_CS
      REAL A_SS(3), Z_SS(3), W_SS(3), RHO_SS


      DATA A_SS/55.85, 52., 58.69/	  !Atomic wt for Fe, Cr, Ni
      DATA Z_SS/26., 24., 28./		  !Atomic no for Fe, Cr, Ni
      DATA W_SS/0.72, 0.18, 0.1/	  !Mix ratio for Fe, Cr, Ni
      DATA RHO_SS/8.03/			  !SS density

      DATA A_AIR/14.01, 16.00, 39.95/     !Atomic wt. for N, O, A
      DATA Z_AIR /7.,   8.,    18./       !Z for N, O, A
      DATA W_AIR /.7808, .2095, .0047/    !Mixture ratio for N, O, A
      DATA RHO_AIR /0.0012/

      DATA A_CH /12.01, 1.01/             !Atomic wt. for carbon, hydrogen
      DATA Z_CH  /6.,   1./               !Z for carbon, hydrogen
      DATA W_CH  /1.,   1./               !Mixture ratio for CH
      DATA RHO_CH /1.032/
      DATA W_CH2/1.,   2./                !Mixture ratio for CH2

      DATA A_WASH /55.85, 207.190/
      DATA Z_WASH /26., 82./
      DATA W_WASH /0.19, 0.81/
      DATA RHO_WASH /10.68/

      DATA Z_ROCK/ 6.,    8.,   12.,   20./   !Z's for rock: C, O, Mg, Ca
      DATA A_ROCK/12.01, 16.00, 24.31, 40.08/ !A's for rock
      DATA W_ROCK/ 2.,    6.,    1.,    1./   !Mixture ratio's for rock
      DATA RHO_ROCK /2.8/                     !Rock density
C
      DATA Z_WATER/1., 8./
      DATA A_WATER/1., 16./
      DATA W_WATER/2., 1./
      DATA RHO_WATER/1./

      DATA A_CS/137./
      DATA Z_CS/55./
      DATA RHO_CS/1.93/
      DATA RADL_CS/4.57/		!Radiation lengh of Cs
      DATA ABSL_CS/1./			!Absorption length of Cs
C
C
C    Define material identifiers
C
      INTEGER AIRMAT, SCINTMAT, LH2MAT, LD2MAT, ROCKMAT, EXTMAT
      INTEGER WASHMAT, MINOSMAT, CSMAT, WATERMAT, SKINMAT, SSMAT
      PARAMETER (AIRMAT = 30) 
      PARAMETER (SCINTMAT = 31)
      PARAMETER (LH2MAT = 32)
      PARAMETER (LD2MAT = 33) 
      PARAMETER (ROCKMAT = 34) 
      PARAMETER (EXTMAT = 35) 
      PARAMETER (WASHMAT = 36)
      PARAMETER (MINOSMAT = 37) 
      PARAMETER (CSMAT = 38) 
      PARAMETER (WATERMAT = 39) 
      PARAMETER (SKINMAT = 40)
      PARAMETER (SSMAT = 41)  
  


C    Define tracking medium identifiers
C+  New materials should only be assigned ODD numbers
C+  (the even numbered version, with field, will be created automatically)
C
      INTEGER IMATAIR,IMATSCINT,IMATCARBON,IMATIRON,
     +        IMATLH2,IMATLD2,IMATROCK,
     +        IMATEXT,IMATLEAD,IMATALUM, IMATWASH, IMATMINOS,IMATCS, 
     +        IMATWATER,
     +        IMATSKIN, IMATSS
      PARAMETER (IMATAIR = 1)
      PARAMETER (IMATSCINT = 3)
      PARAMETER (IMATCARBON = 5)
      PARAMETER (IMATIRON = 7)
      PARAMETER (IMATLH2 = 9)
      PARAMETER (IMATLD2 = 11)
      PARAMETER (IMATROCK = 13)
      PARAMETER (IMATEXT = 15)
      PARAMETER (IMATLEAD = 17)
      PARAMETER (IMATALUM = 19)
      PARAMETER (IMATWASH = 21)
      PARAMETER (IMATMINOS = 23)
      PARAMETER (IMATCS = 25)
      PARAMETER (IMATWATER = 27)
      PARAMETER (IMATSKIN = 29)
      PARAMETER (IMATSS = 31)

