Co-60 is produced from Co-50 through neutron activation. Neutron flux 10^18 nuetrons/(s*m^2). cross section is 20 barns and the mass of Co-50 40mg. How many Co-60 are produced in one week? My attempt: I multiplied the flux by the seconds in one week and by 20 barns in m^2 and got 0.0122 neutrons. Then found how many atoms are in the 40mg of CO-50 which was 4.08598x10^20 atoms. Then i multiplied the amount of atoms by the number of neutrons in Co-59 and add to the number of neutrons found by the flux and then divided by 33 neutrons for how many are in C0-60. This gave me the number of nuclei of Co-60 found which was not the right answer.