A 75 kg laboratory technician working with the radioactive isotope 137Cs receives an accidental 100 mrem exposure. 137Cs emits 0.66 MeV γ-ray photons.

a) How many γ- ray photons are absorbed in the technician’s body?

b) How many rad of alpha radiation with an RBE of 10 will cause the same biological damage as the gamma ray above?

For a) I got 7.1 x 10^11

I can't figure out b)

PLEASE HELP!!

rad=10*your answer to a.

To calculate the number of γ-ray photons absorbed in the technician's body, you need to convert the dose received from millirem (mrem) to Joules (J). Once you have the energy, you can use it to calculate the number of photons absorbed.

Given:
- Technician's weight (m) = 75 kg
- Dose received = 100 mrem
- Energy per γ-ray photon (E) = 0.66 MeV = 0.66 x 10^6 electron volts (eV)

a) First, convert the dose from mrem to J using the conversion factor: 1 rem = 0.01 J/kg.

Dose (D) = (100 mrem) x (0.01 J/kg) x (75 kg) = 75 J

Once you have the energy, you can calculate the number of photons absorbed using the relationship: Energy = Number of photons x Energy per photon.

Number of photons (N) = D / E
Number of photons (N) = 75 J / (0.66 x 10^6 eV) = 1.13 x 10^8 photons

Therefore, the number of γ-ray photons absorbed in the technician's body is approximately 1.13 x 10^8.

Now, let's move on to part b.

For b), you need to calculate how many rads of alpha radiation with an RBE (Relativistic Biological Effectiveness) of 10 would cause the same biological damage as the given gamma ray.

The dose unit rad refers to the absorbed dose of ionizing radiation.

To calculate the equivalent dose, you need to multiply the absorbed dose by the radiation weighting factor (RBE).

Equivalent dose (H) = Absorbed dose (D) x RBE

Since the RBE of alpha radiation is given as 10, you can set up the equation as:

H(alpha) = D(alpha) x 10
H(gamma) = D(gamma)

You want to find D(alpha) (the absorbed dose of alpha radiation that causes the same biological effect as D(gamma)).

D(alpha) = D(gamma) / 10
D(alpha) = 75 J / 10 = 7.5 J

Therefore, the absorbed dose of alpha radiation that will cause the same biological effect as the given gamma ray is approximately 7.5 J.

Note that it is important to consult with a professional in the field of radiation biology or radiation safety to accurately assess and interpret the potential biological damage caused by different types of radiation.