Difference between revisions of "Measurements and Calculations (Introduction to Radiochemistry)"
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==== Background ====  ==== Background ====  
−  Note down the values from the background counting you started the day before.<br> Counting number N<sub>bck</sub>= counts<br> Counting time t<sub>bck</sub>= sec<br> Counting speed <math>\frac{N_{bck}}{t_{bck}}</math>  +  Note down the values from the background counting you started the day before.<br> Counting number N<sub>bck</sub>= counts<br> Counting time t<sub>bck</sub>= sec<br> Counting speed <math>\frac{N_{bck}}{t_{bck}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{cps}</math> <br> Standard deviation <math>\frac{\sqrt{N_{bck}}}{t_{bck}}}=\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\mbox{cps}</math><br> 
==== Counting Efficiency ====  ==== Counting Efficiency ====  
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==== Twenty Measurements with Constant Distance from the Source ====  ==== Twenty Measurements with Constant Distance from the Source ====  
−  Do twenty measurements  +  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  
−    +   <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> 
Revision as of 07:53, 3 July 2012
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Which detector did you use?
Contents
Background
Note down the values from the background counting you started the day before.
Counting number N_{bck}= counts
Counting time t_{bck}= sec
Counting speed
Standard deviation
Counting Efficiency
Do a one minute count on every shelf. Use these measurements to calculate the countingefficiency of the GMdetector in %, for ^{234m}Pa. The activity of the sample can be calculated from the amount of UO_{3} 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  
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
The squere of the mean value
Standard deviation
Discuss the results from and ?
Assessment of the Results
Write down the given measurements and calculate how many % of the countings that are outside of the intervals <NS_{N},N+S_{N} and <N2S_{N},N+2S_{N}>:




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