Problem 5. Argon-41 is produced upon neutron capture reaction (n,γ) by Argon-40, which present in a small quantity in air. In the following calculations, assume that neutrons have a flux of 1.4×1012 n/s·cm2. a) Show that concentration of Ar-40 in air is 4.86 × 1017 atoms/cm3. b) Determine production rate of Ar-41 in atoms/s·cm3 when air is exposed to neutrons. c) Estimate equilibrium concentration of Ar-41 in atoms/cm3 when air is exposed to a constant neutron flux for a long period. Here you need to consider that Ar-41 undergoes radioactive decay and at equilibrium production and radioactive decay are equal. d) Calculate total activity of Ar-41atoms in 250 cm3 of air under conditions described in (c). e) Show that initial concentration of Ar-41 inside a building with dimensions 50 × 50 × 10 m3 is 9.74 × 10-8 μCi/cm3 when 250 cm3 air-filled rabbit capsule exposed to neutrons for long period is opened and dispersed uniformly inside the building. Atomic fraction of argon-40 in air is 9.3×10-3. Molecular weight and density of air are 14.4 g/mol and 1.25×10-3 g/cm3, respectively. Absorption cross-section for neutron capture by Ar-40 is 0.53 barns.