Gd-148 is a radioactive isotope that decays by alpha emission. Each alpha partic

Question

Gd-148 is a radioactive isotope that decays by alpha emission. Each alpha particle emitted carries 5.10E-13 J of kinetic energy. A 80.0 kg worker is accidentally exposed to a sample of Gd-148 having an activity of 0.0500 curies for a total of 5.00 minutes. During that time the workers body absorbs 5.00 percent of the alpha particles emitted by the sample. How many alpha particles were emitted by the sample during the time of the workers exposure? alpha particles emitted How many Joules of energy were absorbed by the worker? Joules The alpha particles emitted by the sample have an RBE = 20. Calculate the workers exposure in milliliters. Exposure = milliliters

Explanation / Answer

Activity of Am-241 = 0.0500 Ci

Time of absorbtion of radiation : 5 min = 3 x 60 = 300 sec

1 Ci = 3.7 x 1010 dps (dps: disintegrations per second)

So 0.000 Ci corresponds to 0.0600 Ci x 3.7 x 1010 dps = 1.85x 109 dps

No. of alpha particles emitted in 5.00 minutes = 1.85x 109 x 300 =399.6x109 = 5.55x1011

5.55x1011 alpha particles were emitted by the sample during the time of the workers exposure

Energy of one alpha particle = 5.10x10-13 J

Percentage absorption of alpha particles by the human body = 5%

So the energy absorbed due to alpha particles is : (5/100) x 5.55x1011 x 5.10 x10-13 J = 0.01415 J = 14.15 mJ

14.15 mJ of energy was absorbed by the worker

Exposure calculations:

RBE = 20

Rem = (Energy absorbed /Mass) x RBE

Rad = (14.15 mJ/ 80 kg) x 20 = 3.54 mSv

Dose in Rem = 3.54 x 100 = 354 rem

Related Questions

Navigate

• Browse (All)
• Browse G
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.