Question

Q a)An 83.0–kg man receives an effective dose of 2.40 mSv/year from constant exposure to ²²⁶Ra.

Each ²²⁶Ra decay emits a 4.80–MeV α particle with an RBE of 20.

How many alpha particles does he absorb each year?

b)Calculate the mass of ²²⁶Ra needed to generate the alpha particles in problem above

Answer 1

dosage inlyear 2.40 mSv-0.240rem -dosage 0.240remx_0 RBE -0.240remx-0.012000rad 20 total energy released-001200-x 83.0 kg-0.9960 J kg energy released by each 226Ra nucleon- 4.80 MeV 0.9960J total number of nuclear decays happendinlyear -N- -1.2951e + 012 4.80 MeV since eachdecay will emit one alpha particle total number of alpha particle absorbed by the person in lyear -N-1.2951e+012 initial number of 226 Ra nucleus required before 1 year = No In2 0.6931 disintegration constatn λ=- -4.3319e-04/ year 1/2 1600yrs we plug the valuesin hand while using the relation gives 2.9904e +015 molar massof 226Ra 226.025g 2.9904e+015 nuclei 226.025 gm1.1224e- 06gm mass of No nuclei-m- 6.022e 023