media{
     scattering{1, 1 extinction .09} //.05  1= baseline
     samples 3,10 // 1m12s 7, 22//1m46s 15, 50 // 2m45s  30, 100
     intervals 10 //5 to 100 longer than 10 reference
     ratio .199 // .499= 6min .999=44min .199=4:30
     confidence .9 // .5=4:49 .9=4.49 
     variance 1/10000 // 1/1000=20 min
     }
