Calculate the dose in rem/y for the lungs of a weapons plant employee who inhales and retains an activity of 1.00 μCi of ²³⁹Pu in an accident. The mass of affected lung tissue is 2.00 kg, the plutonium decays by emission of a 5.23-MeV α particle, and you may assume the higher value of the RBE for α s from Table 32.2.

Strategy

Dose in rem is defined by 1 rad = 0.01 J/kg and rem = rad X RBE. The energy deposited is divided by the mass of tissue affected and then multiplied by the RBE. The latter two quantities are given, and so the main task in this example will be to find the energy deposited in one year. Since the activity of the source is given, we can calculate the number of decays, multiply by the energy per decay, and convert MeV to joules to get the total energy.

Data from Table 32.2

Transcribed Image Text:

Type and energy of radiation X-rays y rays B rays greater than 32 keV Brays less than 32 keV Neutrons, fast (1-10 MeV) 1 Protons (1-10 MeV) x rays from radioactive decay Heavy ions from accelerators 1 1 Neutrons, thermal to slow (<20 keV) 2-5 1.7 10 (body), 32 (eyes) 10 (body), 32 (eyes) 10-20 RBE¹ 10-20