Question

Calculate the radiation dosage (in grays) for an 75-kg person that is exposed for 5.0 seconds to a 3.0 Ci source of beta radiation. Assume that 100% of the radiation is absorbed and each beta particle has an energy of 2.0× 10–13 J.

Answer 1

3.0 Ci x (3.7x10^10 decays per sec / 1 Ci ) = 1.11x10^11 decays/second

I found out that absorbed dose (D) is the energy (E) absorbed per unit mass (m) of the absorbing material. The absorbed dose can be calculated by using the following relationship.

D = {E \ m}

The unit of absorbed dose is the gray (Gy) where one gray is one joule per kilogram (J kg-1).

I just don't understand how to relate D to the decays/second.

The solution wouldn't be as simple as saying:

D = 1.7x10^13 J / 75 kg

= 2.15x10^-15 J/kg

or 2.15x10^-13 Gy

3.0 Ci x (3.7x10^10 decays per sec / 1 Ci ) = 1.11x10^11 decays/second

I found out that absorbed dose (D) is the energy (E) absorbed per unit mass (m) of the absorbing material. The absorbed dose can be calculated by using the following relationship.

D = {E \ m}

The unit of absorbed dose is the gray (Gy) where one gray is one joule per kilogram (J kg-1).

I just don't understand how to relate D to the decays/second.

The solution wouldn't be as simple as saying:

D = 1.7x10^13 J / 75 kg

= 2.15x10^-15 J/kg

or 2.15x10^-13 Gy