Measurements and Calculations (Introduction to Radiochemistry)
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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 = cps
Standard deviation = cps
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 on 1 minute with the source in the same position. Calculate the standard deviation and complete the table:
Nr  N_{p}  
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.