Solve the thickness of paper needed to block 99% of Beta rays from Strontium. So

Question

Solve the thickness of paper needed to block 99% of Beta rays from Strontium.
Solve the thickness of iron needed to block 99% of Gamma rays. I'm quiet confused on how to solve for these. It also states that when 99% of Beta radiation remains, then only 1% of the radiation intensity remains. Everything you need to solve it should be there, please help? diation composition of different sources: gamma beta gamma beta enetration factors for Brays from Sr passing through pa 17, soo Initial radiation intensity (full emission): CPM Final radiation intensity with 50 absorbing cards: CPM Thickness of 50 absorbing cards in centimeters: Penetration factor for Sr passing through paper: (Show calculations) 60) to 3 you Thickness of paper needed to block 99% of the B rays from sr: cm (Show calculations) assing through iron Initial radiation intensity (with on at CPM CPM Final radiation intensity with 5 absorbing plates: Thickness of 4 absorbing plates in centimeters: cm, Penetration factor for Co passing through iron: (Show calculations) Thickness of iron needed to block 99% ofthe y rays from 60Co: cm (Show calculations)

Explanation / Answer

the intensity due to sheilding of a paper of thickness x of linear attenuation factor n is given by

IB = IA e-nx

where IB and IA are the final and initial intensity respectively.

here IB /IA = 0.01,

thus, e-nx = 0.01

in the case of paper x = 1 cm.

hence 450 = 17500e-nx

here x = 1cm.

n = ln(0.02571)

n= 3.66;

there thickness of the paper for 99% attenuation of beta ray is as below

x = (-1/3.66)*ln(0.01) = 1.258 cm

In the second case for one plate the intensity is 1000 cpm keeping 4 additional iron plates the intensity become 600 CPM. the thickness of the 4 plates are 1.78 cm suppose the attenuation factor is n thus

600 = 1000* exp(-n*1.78);

hence n = 0.399

let for 99% attenuation the thickness of the iron plate is t

0.01 = exp(-0.399 * t)

t = -(1/0.399)*ln(0.01) = 11.542 cm

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

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