# Measurements and Calculations (Introduction to Radiochemistry)

Which detector did you use?

#### Background

Note down the values from the background counting you started the day before.
Counting number:
Counting time:




Counting speed:
Standard deviation:

#### 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 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 <N-SN,N+SN and <N-2SN,N+2SN>:

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