# Determining the uncertainity in Geiger Counter data

• learningastronomy
In summary, Poisson seems like a reasonable way to measure the uncertainty in a single trial where the process is Poisson. However, since the uncertainty is so small it becomes insignificant.
learningastronomy
Homework Statement
I have a list of counts that are taken from a Geiger Counter based off only one trial. There were 20 runs taken with different voltages. The voltage ranged from 500 to 1000 and the counts ranged from 20,000 to 100,000.
Relevant Equations
Let c be counts therefore uncertainty is ##\sqrt{c}##.
From what I understand thus far is the counting involves Poisson therefore the uncertainty is just the square root of the counts, correct? But when I take the square root of the counts it produces a very small number compared to the count which makes it insignificant therefore the error bars that I want to produce aren't visible because the uncertainty is so small. Am I correct in using Poisson to measure the uncertainty? There was only one trial done.

learningastronomy said:
Homework Statement:: I have a list of counts that are taken from a Geiger Counter based off only one trial. There were 20 runs taken with different voltages. The voltage ranged from 500 to 1000 and the counts ranged from 20,000 to 100,000.
Relevant Equations:: Let c be counts therefore uncertainty is ##\sqrt{c}##.

From what I understand thus far is the counting involves Poisson therefore the uncertainty is just the square root of the counts, correct? But when I take the square root of the counts it produces a very small number compared to the count which makes it insignificant therefore the error bars that I want to produce aren't visible because the uncertainty is so small. Am I correct in using Poisson to measure the uncertainty? There was only one trial done.
The description is not clear to me.

Is it that, on the basis that the process is Poisson, you want the uncertainty in the Poisson rate as deduced from a single count? My understanding is that if you estimate the parameter from a single Poisson count the standard error in that estimate is indeed the square root of the count. Yes, with such large counts this will be a relatively small number.

Last edited:
haruspex said:
The description is not clear to me.

Is it that, on the basis that the process is Poisson, you want the uncertainty in the Poisson rate as deduced from a single count? My understanding is that if you estimate the parameter from a single Poisson count the standard error in that estimate is indeed the square root of the count. Yes, with such large counts this will be a relatively small number.

The process does not have to be Poisson, I just assumed to use Poisson to compute the uncertainty. If there was only one trial in the experiment how do I solve for the uncertainty/error bars? Will Poisson suffice even though the uncertainty is so small it becomes insignificant?

learningastronomy said:
The process does not have to be Poisson, I just assumed to use Poisson to compute the uncertainty. If there was only one trial in the experiment how do I solve for the uncertainty/error bars? Will Poisson suffice even though the uncertainty is so small it becomes insignificant?
To get an answer you have to make an assumption about the nature of the distribution, and Poisson seems entirely reasonable.
I see no objection to what you have done. The error bars will really be that small.

learningastronomy
haruspex said:
To get an answer you have to make an assumption about the nature of the distribution, and Poisson seems entirely reasonable.
I see no objection to what you have done. The error bars will really be that small.
Oh I see, thank you!

## 1. How is uncertainty calculated in Geiger Counter data?

Uncertainty in Geiger Counter data is typically calculated using statistical methods such as standard deviation or confidence intervals. These methods take into account the variability and randomness of the data to determine a range of values within which the true value is likely to fall.

## 2. What factors can contribute to uncertainty in Geiger Counter data?

There are several factors that can contribute to uncertainty in Geiger Counter data, including instrument error, environmental conditions, operator error, and natural variability in radioactive sources. It is important to consider and control for these factors when determining uncertainty in Geiger Counter data.

## 3. How can uncertainty in Geiger Counter data be reduced?

Uncertainty in Geiger Counter data can be reduced by using high-quality instruments, ensuring proper calibration and maintenance, controlling for environmental factors, and taking multiple measurements. Additionally, using statistical methods to analyze the data can help to reduce uncertainty.

## 4. Is it necessary to determine uncertainty in Geiger Counter data?

Yes, it is important to determine uncertainty in Geiger Counter data in order to accurately interpret and compare results. Without taking uncertainty into account, the data may be misleading or inaccurate, which could have serious consequences in fields such as nuclear safety and environmental monitoring.

## 5. Can uncertainty in Geiger Counter data be eliminated completely?

No, it is not possible to eliminate uncertainty completely in Geiger Counter data or any scientific measurement. However, by following best practices and using appropriate statistical methods, uncertainty can be minimized and the accuracy and reliability of the data can be improved.

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