5 (a) Compare the Me/ p value obtained from Eq. (9.39) in the textbook with the value 13.4 cm g obtained experimentally by Paliwal and Almond (1976) for the case of LiF irradiated by Co y rays. (b) What constant is needed on the right-hand side of Eq. (9.39) in place of 0.01 to give exact agreement? Answer: 17.8 cm2 g ', 0.031\fSolution: (a) From Eq. (9.39) e He Imax = 0.01 He tmax = He x p tmax = 4.605 p From the text following Eq. (9.39), and considering that ZLIF = 7.5 (see the Data Tables), we approximate p tmax = 0.95 RCSDA, Where RCSDA is the range (g/cm2) of electrons having the mean initial energy E, result- ing from Compton interactions: KN E = kx tr 8.885 X 10-26 OKN = 1.25 X 1.888 x 10-25 = 0.588 MeV and RCSDA (0.588 MeV) = 0.2725 g cm-2 from the Data Tables. Therefore p tax = 0.95 X 0.2725 = 0.2589 gcm-2 and Me/p = 4.605/ 0.2589 = 17.8 cm2 g-1: (b) p tmax X - He = 0.2589 X 13.4 = 3.47 P and e-3.47 = 0.031 Note that Janssens et al. (1974) proposed 0.04