Difference between revisions of "Measurements and Calculations (Introduction to Radiochemistry)"
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− | Which detector did you use? | + | <br> |
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+ | Return to [[Introduction to Radiochemistry - Counting statistics|Main]] <br> <br> | ||
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+ | Which detector did you use? | ||
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==== Background ==== | ==== Background ==== | ||
− | Note down the values from the background counting you started the day before.<br> Counting number | + | 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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− | | Counting number for each shelf (CPM) | + | | align="center" | Counting number for each shelf (CPM) |
− | | Counting Efficency | + | | 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 | + | 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;" | ||
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| 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> | ||
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+ | | SUM: | ||
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+ | | SUM: | ||
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+ | |} | ||
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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>? | ||
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+ | ==== Assessment of the Results ==== | ||
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+ | <br> <br> <br> Write down the given measurements and calculate how many % of the countings that are outside of the intervals <N-S<sub>N</sub>,N+S<sub>N</sub>> and <N-2S<sub>N</sub>,N+2S<sub>N</sub>>: | ||
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+ | {| cellspacing="1" cellpadding="1" border="1" width="200" | ||
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+ | | <math>\overline{N}</math> | ||
+ | | <math>\sqrt{\overline{N}}</math> | ||
+ | | <math>N\pm S_{N}</math> | ||
+ | | <math>N\pm 2S_{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. | |
− | + | [[Category:Half_life]] [[Category:Natural_activity]] [[Category:Human_Produced_Radioactivity]] [[Category:Laboratory_exercise]] [[Category:Detection]] [[Category:Gamma_Detector]] [[Category:Master]] | |
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Latest revision as of 18:47, 11 November 2013
Return to Main
Which detector did you use?
Contents
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.
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Counting number for each shelf (CPM) | Counting Efficency |
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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:
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SUM: | |
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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>:
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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.