How Do You Calculate the Activity of a Radioactive Sample?

AI Thread Summary
To calculate the activity of a radioactive sample, the Geiger counter registers 2 counts per second at a distance of 0.12 m. The initial calculation suggests an intensity of 10,000 counts/s/m² based on the counts and area. However, the accuracy of this estimate is questioned, as not all emitted particles are detected by the counter. The discussion highlights the challenge of accounting for the detection efficiency and the assumption of uniform emission in all directions. Understanding these factors is crucial for an accurate calculation of the sample's activity.
jumbogala
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Homework Statement


The sample is placed 0.12 m beneath a Geiger counter.

The counter registers 2 counts per second. What is the activity of the sample?

Homework Equations


The Attempt at a Solution


Just a guess. I am making up formulas here so please tell me if they're not even true.

(2 counts/s)/(2E-4 m2) = Intensity = 10 000 counts/s/m2

Then multiply this by the distance to get the activity? So this would give 1200 counts/s?

Is that correct?
 
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Do you suppose that all the particles emitted by the sample are being captured by the Geiger counter?
 
Nope, they're not. But I don't know how to account for that, since I have no idea what percentage are.
 
jumbogala said:
Nope, they're not. But I don't know how to account for that, since I have no idea what percentage are.

What if you assumed that the sample emits uniformly in all directions?
 

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