Calculating New Emission Rate of Radioactive Source

In summary, the formula for calculating the new emission rate of a radioactive source is New Emission Rate = Initial Emission Rate x (Current Half-life / New Half-life)^2. The current half-life of a radioactive source can be determined by measuring the amount of time it takes for half of the radioactive material to decay. Factors such as measurement errors, changes in the physical environment, and the presence of other radioactive materials can affect the accuracy of the calculated emission rate. The emission rate of a radioactive source can change over time due to decay and changes in the physical environment, and is typically measured in units of becquerels (Bq) or curies (Ci).
  • #1
araz1
9
0
A radioactive source emits particles at an average rate of 1 pe second. Assume that the number of emissions follows a Poisson distribution. The emission rate changes such that the probability of 0 or 1 emission in 4 seconds becomes 0.8. What is the new rate? Thanks.
 
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  • #2
araz said:
A radioactive source emits particles at an average rate of 1 pe second. Assume that the number of emissions follows a Poisson distribution. The emission rate changes such that the probability of 0 or 1 emission in 4 seconds becomes 0.8. What is the new rate? Thanks.

Hi araz, welcome to MHB! ;)

We have:
$$P(\text{0 or 1 emission in 4 seconds})=0.8 \\ \implies
P(\text{0 emission in 4 seconds}) + P(\text{1 emission in 4 seconds}) = \frac{\lambda^0 e^{-\lambda}}{0!} + \frac{\lambda^1 e^{-\lambda}}{1!} = (1+\lambda)e^{-\lambda} = 0.8 \\ \implies
\lambda \approx 0.824
$$
So the average number of emissions in 4 seconds is $0.824$, which is $0.206$ per second.
 
  • #3
Klaas van Aarsen said:
Hi araz, welcome to MHB! ;)

We have:
$$P(\text{0 or 1 emission in 4 seconds})=0.8 \\ \implies
P(\text{0 emission in 4 seconds}) + P(\text{1 emission in 4 seconds}) = \frac{\lambda^0 e^{-\lambda}}{0!} + \frac{\lambda^1 e^{-\lambda}}{1!} = (1+\lambda)e^{-\lambda} = 0.8 \\ \implies
\lambda \approx 0.824
$$
So the average number of emissions in 4 seconds is $0.824$, which is $0.206$ per second.

Thank you Klaas. Did you use guess and check or numerical methods to get 0.824?
Regards
 
  • #4
araz said:
Thank you Klaas. Did you use guess and check or numerical methods to get 0.824?
Regards

I used an online calculator to find it.
Alternatively guessing can work, or we can look it up in a Poisson distribution table.
 

FAQ: Calculating New Emission Rate of Radioactive Source

What is the formula for calculating the new emission rate of a radioactive source?

The formula for calculating the new emission rate of a radioactive source is: New Emission Rate = Initial Emission Rate x (Current Half-life / New Half-life)^2.

How do you determine the current half-life of a radioactive source?

The current half-life of a radioactive source can be determined by measuring the amount of time it takes for half of the radioactive material to decay. This can be done through various methods such as counting the number of decays per second or measuring the intensity of the radiation emitted.

What factors can affect the accuracy of the calculated emission rate?

The accuracy of the calculated emission rate can be affected by factors such as measurement errors, changes in the physical environment of the radioactive source, and the presence of other radioactive materials that may interfere with the decay process.

Can the emission rate of a radioactive source change over time?

Yes, the emission rate of a radioactive source can change over time due to factors such as decay and changes in the physical environment. This is why it is important to regularly recalculate the emission rate to ensure accurate results.

What units are typically used for the emission rate of a radioactive source?

The emission rate of a radioactive source is typically measured in units of becquerels (Bq) or curies (Ci). These units represent the number of decays per second or the amount of radioactive material present in a sample.

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