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(Twenty Measurements with Constant Distance from the Source)
 
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Return to [[Introduction to Radiochemistry - Counting statistics|Main]]
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Return to [[Introduction to Radiochemistry - Counting statistics|Main]] <br> <br>  
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Which detector did you use?
  
Which detector did you use?
 
 
==== Background  ====
 
==== Background  ====
  
Note down the values from the background counting you started the day before.<br> Counting number N<sub>bck</sub>= &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; counts<br> Counting time t<sub>bck</sub>= &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; sec<br> Counting speed <math>\frac{N_{bck}}{t_{bck}}</math> = &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; cps<br> Standard deviation <math>\frac{\sqrt{N_{bck}}}{t_{bck}}</math>=&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cps<br>
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Note down the values from the background counting you started the day before.<br> Counting number:<br> <math>N_{bck}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}</math><br> Counting time:<br><math>t_{bck}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{sec}</math><br>  
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Counting speed:<br> <math>\frac{N_{bck}}{t_{bck}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{cps}</math> <br> Standard deviation:<br> <math>\frac{\sqrt{N_{bck}}}{t_{bck}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{cps}</math>  
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==== Counting Efficiency  ====
 
==== Counting Efficiency  ====
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{| cellspacing="1" cellpadding="1" border="1" style="width: 564px; height: 147px;"
 
{| cellspacing="1" cellpadding="1" border="1" style="width: 564px; height: 147px;"
 
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| <br>
| Counting number for each shelf (CPM)  
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| align="center" | Counting number for each shelf (CPM)  
| Counting Efficency
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| align="center" | Counting Efficency
 
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==== Twenty Measurements with Constant Distance from the Source  ====
 
==== Twenty Measurements with Constant Distance from the Source  ====
  
Do twenty measurements on 1 minute with the source in the same position. Calculate the standard deviation and complete the table:  
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Do twenty measurements lasting for one minute with the source in the same position. Calculate the standard deviation and complete the table:  
  
 
{| cellspacing="1" cellpadding="1" border="1" style="width: 547px; height: 487px;"
 
{| cellspacing="1" cellpadding="1" border="1" style="width: 547px; height: 487px;"
 
|-
 
|-
 
| Nr  
 
| Nr  
| N<sub>p</sub>  
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| <math>N_{P}\,</math>  
 
| <math>N_{P}-\overline{N}</math>  
 
| <math>N_{P}-\overline{N}</math>  
 
| <math>\left(N_{P}-\overline{N}\right)^{2}</math>
 
| <math>\left(N_{P}-\overline{N}\right)^{2}</math>
 
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| 12  
 
| 12  
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| 13  
 
| 13  
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| 14  
 
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| 16  
 
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| 17  
 
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| SUM:  
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| SUM:  
 
| SUM:  
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<br>  
 
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<br> Mean value of the counting numbers <br> <math>\overline{N}=\frac{\sum N_{P}}{20}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}</math><br> The squere of the mean value <math>\sqrt{\overline{N}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}</math><br> Standard deviation <math>S_{N}=\sqrt{\frac{\left(N_{P}-\overline{N}\right)^{2}}{19}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}</math><br> Discuss the results from <math>S_{N}\,</math>and <math> \sqrt{\overline{N}}</math>?  
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<br> Mean value of the counting numbers <br> <math>\overline{N}=\frac{\sum N_{P}}{20}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}</math><br> The squere of the mean value <math>\sqrt{\overline{N}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}</math><br> Standard deviation <math>S_{N}=\sqrt{\frac{\sum\left(N_{P}-\overline{N}\right)^{2}}{19}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}</math><br> Discuss the results from <math>S_{N}\,</math>and <math> \sqrt{\overline{N}}</math>?
  
 
==== Assessment of the Results  ====
 
==== Assessment of the Results  ====
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Write down the given measurements and calculate how many&nbsp;% of the countings that are outside of the intervals &lt;N-S<sub>N</sub>,N+S<sub>N</sub> and &lt;N-2S<sub>N</sub>,N+2S<sub>N</sub>&gt;:
 
  
{| width="200" cellspacing="1" cellpadding="1" border="1"
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<br> <br> <br> Write down the given measurements and calculate how many&nbsp;% of the countings that are outside of the intervals &lt;N-S<sub>N</sub>,N+S<sub>N</sub>&gt and &lt;N-2S<sub>N</sub>,N+2S<sub>N</sub>&gt;:
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{| cellspacing="1" cellpadding="1" border="1" width="200"
 
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| <math>\overline{N}</math>  
 
| <math>\overline{N}</math>  
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Is there, in your opinion, to many single measurements outside of the given areas? Give a answer based on statistical normal distribution.
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Is there, in your opinion, to many single measurements outside of the given areas? Give a answer based on statistical normal distribution.  
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[[Category:Half_life]] [[Category:Natural_activity]] [[Category:Human_Produced_Radioactivity]] [[Category:Laboratory_exercise]] [[Category:Detection]] [[Category:Gamma_Detector]] [[Category:Master]]

Latest revision as of 17:47, 11 November 2013


Return to Main

Which detector did you use?

Background

Note down the values from the background counting you started the day before.
Counting number:
[math]N_{bck}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}[/math]
Counting time:
[math]t_{bck}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{sec}[/math]

Counting speed:
[math]\frac{N_{bck}}{t_{bck}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{cps}[/math]
Standard deviation:
[math]\frac{\sqrt{N_{bck}}}{t_{bck}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{cps}[/math]


Counting Efficiency

Do a one minute count on every shelf. Use these measurements to calculate the counting-efficiency of the GM-detector in %, for 234mPa. The activity of the sample can be calculated from the amount of UO3 used.


Counting number for each shelf (CPM) Counting Efficency
1

2

3

4


Twenty Measurements with Constant Distance from the Source

Do twenty measurements lasting for one minute with the source in the same position. Calculate the standard deviation and complete the table:

Nr [math]N_{P}\,[/math] [math]N_{P}-\overline{N}[/math] [math]\left(N_{P}-\overline{N}\right)^{2}[/math]
1


2


3


4


5


6


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11


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16


17


18


19


20


SUM:
SUM:



Mean value of the counting numbers
[math]\overline{N}=\frac{\sum N_{P}}{20}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}[/math]
The squere of the mean value [math]\sqrt{\overline{N}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{counts}[/math]
Standard deviation [math]S_{N}=\sqrt{\frac{\sum\left(N_{P}-\overline{N}\right)^{2}}{19}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}[/math]
Discuss the results from [math]S_{N}\,[/math]and [math] \sqrt{\overline{N}}[/math]?

Assessment of the Results




Write down the given measurements and calculate how many % of the countings that are outside of the intervals <N-SN,N+SN&gt and <N-2SN,N+2SN>:

[math]\overline{N}[/math] [math]\sqrt{\overline{N}}[/math] [math]N\pm S_{N}[/math] [math]N\pm 2S_{N}[/math]









Is there, in your opinion, to many single measurements outside of the given areas? Give a answer based on statistical normal distribution.