Question

Jack was exposed to fast neutrons; he received a radiation dose of 160 rem on part of his hand, affecting 25.0 grams of tissue. The relative biological effectiveness (RBE) of these neutrons is 12.0.

a) How much radiation did Jack receive?

b) What was the total energy of the radiation Jack received?

c) Suppose Jill received the same rad dosage, but from beta rays with an RBE of 1.00 instead of from neutrons. What is the value of the equivalent dose she received?

Answer 1

GIven

Radiation dose = 160 rem

Mass of tissue , m = 25 g = 0.025 kg

RBE of neutrons = 12

(a)

The radiation received by Jack = Biological dose equivalent (BDE) / RBE --1

The radiation received by Jack = 160 rem / 12

The radiation received by Jack = 13.33 rad

(b)

Since 1 rad = 0.01 J / kg

So, 13.33 rad = 0.01 * 13.33 J / kg = 0.133 J / kg

The total energy of radiation received by Jack = 0.133 * 0.025 = 3.33 *10^-3 J

(c)

For Jill

Absorbed radiation dosage = 13.3 rad

RBE = 1

BDE = (Absorbed radiation dosage )* RBE [From eq 1]

BDE = 13.3 rad * 1 = 13.3 rem