Determine the type of radiation (already given) emitted by each of the radioacti

Question

Determine the type of radiation (already given) emitted by each of the radioactive sources, explain why you chose this answer Why do we use lead aprons when getting xrays at the dentist and why specifically lead? Regarding the beta particles, estimate th percent of radiation that passed through one sheet of cardboard and also 2 sheets. What thickness of cardboard would be needed to block 99% of radiation? Answer the same exact question for aluminum. What kind of shielding is needed to protect against gamma rays and what percentage of gamma rays passed through 4 sheets of lead.- is that enough shielding.

Explanation / Answer

(1) Penetration power of alpha, beta and gamma is in the order, alpha < beta <gamma.

Paper can stop alpha particles, wood can stop beta particles and the lead (Pb) can stop gamma radiation.

If we take a look at the table given for penetration powers for all of them then It is decraeasing for Fe-59 from Paper to aluminium sheet which shows beta radiation and as It is completely stopped by lead so it shows gamma radiation also.

For Ga-67, particles are not stopped even by lead so it is a clear indication for gamma radiation.

for I-125, the case is same as of Ga-67 so it is also gamma radiation.

For P-32, the activity count has been decreased to a greater extent when Al sheet is used and no particle is passed through Pb sheet. So, it is beta radiation.

For Rn-222, It is stopped by paper sheet so it is alpha radiation only.

for Sr-185, particles could not be stopped even by using Lead sheet so it is gamma radiation.

(2) X-rays penetration power is very high. Exposure of body vital organs towards X-rays could be dangerous. So, the perpose of lead aprons is to reduce the X-rays radiation for the vital organs of the patients.

Lead has the maximum tendency to stop the effect of ionizing X-rays for the vital organs like the reproductive organs and thyroid gland. While taking the X-ray image of a theeth then lead aprons are must to use since the throid gland could be affected by the X-rays.

questions based on graphs,

(1) initial activity count for beta particles is 80 when the thickness of cardboard is 0. when thickness is increased to 1 mm then acivity count is 30.

so, percent of radiation passed through one sheet of cardboard = (30/80)*100 = 37.5%

when two sheets are used then, (14/80)*100 = 17.5%

If, 99% radiation is stopped then only 1% would be passed. So,

1 = (X/80)*100

0.01 = X/80

X = 0.8

that means the activity would be like 0.8 counts/second and from table the activity is 2 when the thinkness of the sheet is 4 mm. So, to decrease the activity to 0.8 counts/second the thickness of the sheet would be like 5mm.

(2) for one sheet of Al, percent or radiation passed = (7/80)*100 = 8.75%

percentage of radiation passed from 2 sheets of Al = (1/80)*100 = 1.25%

99% of radiation is stopped when the tickness of Al sheet is 2 mm since the acticity count has decraesed from 80 to 1 that means out of 80, 79 particles are stoppsed.

so, (79/80)*100 = 98.75% Or 99%

(3) Lead shielding is neede to protect agains gamma radiation.

percentage of gamma rays passed through 4 sheets = (18/40)*100 = 45%

4 sheets of lead is not like enough shielding since 45% radiation is passed from this which would be injurious to the body.

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