Difference between revisions of "Measurements and Calculations (Introduction to Radiochemistry)"

From mn/safe/nukwik
Jump to: navigation, search
Line 18: Line 18:
 
|-
 
|-
 
| <br>  
 
| <br>  
| Counting number for each shelf (CPM)  
+
| align="center" | Counting number for each shelf (CPM)  
| Counting Efficency
+
| align="center" | Counting Efficency
 
|-
 
|-
 
| 1  
 
| 1  
Line 163: Line 163:
 
<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> and &lt;N-2S<sub>N</sub>,N+2S<sub>N</sub>&gt;:  
 
<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> and &lt;N-2S<sub>N</sub>,N+2S<sub>N</sub>&gt;:  
  
{| width="200" cellspacing="1" cellpadding="1" border="1"
+
{| cellspacing="1" cellpadding="1" border="1" width="200"
 
|-
 
|-
 
| <math>\overline{N}</math>  
 
| <math>\overline{N}</math>  
Line 194: Line 194:
 
Is there, in your opinion, to many single measurements outside of the given areas? Give a answer based on statistical normal distribution.  
 
Is there, in your opinion, to many single measurements outside of the given areas? Give a answer based on statistical normal distribution.  
  
[[Category:Half_life]][[Category:Natural_activity]][[Category:Human_Produced_Radioactivity]][[Category:Laboratory_exercise]][[Category:Detection]][[Category:Gamma_Detector]]
+
[[Category:Half_life]] [[Category:Natural_activity]] [[Category:Human_Produced_Radioactivity]] [[Category:Laboratory_exercise]] [[Category:Detection]] [[Category:Gamma_Detector]]

Revision as of 13:22, 3 July 2012


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


7


8


9


10


11


12


13


14


15


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{\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 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.