| Lab 7 of 2LC| http://www.geocities.com/chcyang| IN-CLASS TEST of Lab 8|
Lab 8 of PHYS 2C LAB
Radioactivity
We skip the work of Section 4, half-life of Ba-137. However, here is "an in-class quiz" to remind you the definition of "half life"!
Section 1, Measure the background counting rate:
What is the average of your background counting rate? What is the unit of your average counts per second, Ave(N)? Show me your work!
Section 2, Histogram of counts per second:
Refer to Equation (12) on page 51.
Data table of Average N, and s , Standard Deviation
|
Ave(N), Unit:( ) |
sExperimental from histogram |
sTheoretical from Ave(N) |
ACCURACY %error of s |
|
Max = |
% | ||
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Half-Max = |
% | ||
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(1/4)Max = |
% |
Ave(N): Average counts per second,
s
: Standard DeviationShow me your work to obtain sTheoretical of your half-Maximum Ave(N).
Question 2-1,
Does your histogram look like a Gaussian?
Requirement:
You have to use your %error of s to answer the question.
Section 3, Poisson Distribution:
Print out the collected data of 3(c) and put that data sheet in your notebook.
Refer to Equation (10) on page 50.
# of events: Number of times (events) which have the same counts.
total # of events: roughly 300 seconds, which depends on your collected data.
Experimental PN versus N: the frequency of occurrence versus N.
Theoretical PN versus N: the calculated Poisson distribution.
Show me your work to calculate:
Average N, and your theoretical s (1 POINT)
Your Experimental and Theoretical P0, and P3 (2 POINTS)
The percent error of P1, and P2 (1 POINT)
Data table of 3(d), (e), and (f)
|
N, Unit:( ) |
# of events |
Experimental PN, (# of events)total # of events |
Theoretical PN |
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0 |
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1 |
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2 |
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3 |
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4 |
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5 |
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6 |
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7 |
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8 |
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9 |
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10 |
Plot a graph of two sets together.
Question 3-1,
Does your data look like the Poisson distribution?
Requirement:
Use the above calculation and your graph to give a quantitative explanation.
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