= 7.61 x 10ll sec. = 2.41 x 104 yrs. Example 14. Calculate the amount of 3.15 day !" Au formed by two successive n, y-reactions when 1 gm of 197Au is exposed for 30 hrs in a neutron flux of 1 x 1014 cm- sec-. The chain of reactions is 2.6 x 104b 199 Am= 2199 199 = 8.4 X Example 15. The yield of 24Na (T, = 14.8 hr.) from the reaction Na (d, p) 24Na is 110 mCi/hr. (a) Calculate the maximum activity of 24Na, (b) the activity after 8 hr continuous bombardment of deuteron and (c) the activity eight hrs after this bombardment.Example 16. If iodine 1301 (T, = 12.6 hr) whose initial strength is 1 mci emits B-rays of average energy 0.29 MeV. If this iodine is present in 2 gm of thyroid tissue, find the radiation dose absorbed in. 24 hr by the tissue in REP