Cosmic Rays:

Issues with Plateauing
Our Adventure with Data Collection
Team: Angela DeHart, Joe Boettcher, Ray Hodges, Starre Williams
08/16-17/2018
2018, Angela DeHart
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License
Cosmic RaysA K-12 Physics Document for teachers
Credit: Simon Swordy (U. Chicago), NASA Image by A. Chantelauze, S. Staffi, and L. Bret

QuarkNet Teacher Training
Teaching STEM has inspired me to make myself open to new possibilities. This summer, inspired by the
amazing after-school physics seminar George Mason University shared with the students at Glasgow
Middle School I applied and was accepted into a summer teacher training with Catholic University’s
QuarkNet.
What is QuarkNet? (https://en.wikipedia.org/wiki/QuarkNet)
QuarkNet is a long-term, research-based teacher professional development program in the United States jointly funded by
the National Science Foundation and the US Department of Energy. Since 1999, QuarkNet has established centers at
universities and national laboratories conducting research in particle physics (also called high-energy physics) across the
United States.
Mentor physicists and physics teachers collaborate to bring cutting-edge physics to (middle and) high school classrooms.
QuarkNet offers research experiences for teachers and students, teacher workshops and sustained follow-on support.
Through these activities, teachers enhance their knowledge and understanding of scientific research and transfer this
experience to their classrooms, engaging students in both the substance and processes of contemporary physics research.

This summer we were introduced to QuarkNet’s Cosmic Ray Study.
(https://en.wikipedia.org/wiki/QuarkNet)
The main QuarkNet student investigations supported at the national level are cosmic ray studies. Working with
Fermilab technicians and research physicists, QuarkNet staff has developed a classroom cosmic ray muon detector
that uses the same technologies as the largest detectors at Fermilab and CERN.
To support interschool collaboration, QuarkNet collaborates with the Interactions in Understanding the Universe
Project (I2U2) to develop and support the Cosmic Ray e-Lab.
An e-Lab is a student-led, teacher-guided investigation using experimental data. Students have an opportunity to
organize and conduct authentic research and experience the environment of a scientific collaboration. Participating
schools set up a detector somewhere at the school. Students collect and upload the data to a central server located
at Argonne National Laboratory. Students can access data from all of the detectors in the cluster and use these data
for studies, such as determining the (mean) lifetime of muons, the overall flux of muons in cosmic rays, or a study of
extended air showers.

This document is a summation of project I, and three
other QuarkNet teachers worked on as our culminating
project.* I am going to use this presentation to tell my
students “what I did this summer.”
The purpose of my participation in QuarkNet is to offer
students traditionally underrepresented in STEM an
opportunity to build a cosmic ray muon detector. Collecting
data on the detector will allow the students a chance to
conduct authentic research as well as the opportunity to
collaborate with the other students involved in QuarkNet’s
Cosmic Ray Study. Not only is this opportunity invaluable to
the development of the 7 essential skills needed for the 21st
century learner, it introduces them to the world of global
scientific collaboration.
https://santamariatimes.com/news/local/education/st-century-learning-sailing-
the-seven-c-s/article_0e50cdb0-3c8d-11df-b267-001cc4c002e0.html
* This summation is solely the work of Angela DeHart and may not express the views or understandings of my team

Abstract
Cosmic rays1 are still a mystery to us. While we know that cosmic rays they are
coming from outer space and that Earth is being bombarded by thousands of
muons2 every second we have not yet been able to determined the full extent of
the impact muons have on the human body, man-made objects, and/or the
weather. The objective of this paper is to configure our cosmic ray detector so that
we can see muons. By establishing our ability to count muons we can conduct
different experiments to extend our understanding of the effect of cosmic rays.

Introduction
The goal of our experiment is to learn the mechanics involved in plateauing3 a
cosmic ray detector4.
In order to achieve our task we have to find the minimum voltage5 necessary
to maximize the signal rate6 while also minimizing the least amount of “noise7”
running through the channel8

Procedure
An overview of our process:

Procedure
Set Channel 2 at a rate of 2400/minute
-Channel 2 is the reference channel
-2400/minute is the single rate reference value
STEP #1

Procedure
A. We need one channel to plateau. We chose to plateau channel 1
-We could have chosen channel 3 or 4
-Any channel, except the reference channel would work
STEP #2
B. We need to choose a starting voltage and then increase the voltage on the multimeter by 0.05 volts
until the coincidence rate remains constant. We choose to start at .50 volts
C. We used a multimeter with the power distribution unit (PDU) to set the voltage of channel 1 to 0.5
volts.
D. We recorded the rates for channel 1, channel 2, and the two fold coincidence rate. We increased
the voltage of channel 1 by 0.05 volts and repeated the measurements of the rates.
E. We continued increasing in the manner until the coincidence rate remained nearly constant (i.e.
reached a plateau).

Procedure
STEP #2
B. We need to choose a starting voltage and then increase the voltage on the multimeter9 by
0.05 volts until the coincidence rate remains constant. We choose .50 volts
C. We used a multimeter with the power distribution unit (PDU)9 to set the voltage of channel 1
to 0.5 volts.
reached a plateau).

Procedure
STEP #2
B. We need to choose a starting voltage and then increase the voltage on the multimeter9 by 0.05 volts
C. We used a multimeter with the power distribution unit (PDU) 9 to set the voltage of channel 1 to 0.5
volts.
D. We recorded the rates for channel 1, channel 2, and the two fold coincidence rate. We
increased the voltage of channel 1 by 0.05 volts and repeated the measurements of the rates.
reached a plateau).

**ISSUE!
STEP #2
1) We encountered some unusual data. The channel rate number was
inconsistent
a) The single rate data for channel 1 jumped dramatically – twice.
-1st occurrence: it jumped over 200,000
-2nd occurrence: It jumped over 10,000,000
x confirmation that we had a problem
You can hear us
discussing the
problem in this 42:27
minute video

**ISSUE!
STEP #2
2) What was the problem?
a) In order to focus on high probably theories we consulted with our teacher
i. We know that the number of photons produced by muons cannot generate these large
numbers
ii. We know that the tape abound scintillator number 1, where the occurrence happened,
was slightly unglued
iii. We know that the scintillator has to be “light-tight”
iv. So we decided to check the accuracy of the “light-tightness” by covering the scintillator
with a coat
i. If we were correct the single rate data for detector number 1 should immediately
and dramatically drop
http://quarknet.fnal.gov/toolkits/ati/fnaldet.html

**ISSUE!
STEP #2
2) Result?
a) We were right!
i. The single rate data for detector number 1
immediately and dramatically dropped
ii. We re-taped the scintillator
iii. We re-tested the data rate – and while it
was still a little high it was accurate enough
for us to continue our experiment
iv. We started collecting data - from scratch

**ISSUE!
STEP #2
2) Result?
a) We were right!
i. The single rate data for detector number 1
immediately and dramatically dropped
ii. We re-taped the scintillator
iii. We re-tested the data rate – and while it
was still a little high it was accurate enough
for us to continue our experiment
iv. We started collecting data - from scratch 5,858 increase
12,812 increase

Procedure
STEP #2
B. We need to choose a starting voltage and then increase the voltage on the multimeter9 by 0.05 volts
C. We used a multimeter with the power distribution unit (PDU) 9 to set the voltage of channel 1 to 0.5
volts.
E. We continued increasing in the manner until the coincidence rate remained nearly constant
(i.e. reached a plateau).

A. We found the coincidence rate plateau level and
created a plot of the data
B. We then tested voltages at increments smaller than 0.05
volts to get a more precise value for the beginning of the
plateau
C. We determined that the plateau value occurred at 0.692
volts with a rate
D. Then we adjusted the voltage of each of the other 3
channels to obtain a rate of nearly 2960
E. We collected data over night
Procedure
STEP #3
http://physics.ucr.edu/~owen/quarknet/6000CRMD_How_to_Plateau.pdf

Procedure
A. We found the coincidence rate plateau level and created
a plot of the data
B. We then tested voltages at increments smaller than
0.05 volts to get a more precise value for the
beginning of the plateau
volts with a rate
STEP #3

Procedure
a plot of the data
plateau
C. We determined that the plateau value occurred at
0.692 volts with a rate (NOTE: the final rate is a choice
between a set of close numbers not a numeric default)
STEP #3

Procedure
a plot of the data
plateau
volts with a rate
(NOTE: You no longer need a reference channel. You now have “the
answer” so ALL the channels are plateaued to the same rate)
STEP #3

Procedure
a plot of the data
plateau
volts with a rate
STEP #3

Procedure
A. We went to look at our data results:
ISSUE!
B. We uploaded the data we had but made a
“note to file” because of the “high” read of
channel #1
C. DONE!
STEP #4

**ISSUE!
STEP #4
1) We review the possibilities
a. Yesterday there was a “spike” in our data readings around
2:30am (different experiment)
b. The computer was not collecting data when we arrived into
work. The screen was black. We had to wait for the owner
to come and sign in on the computer to see what was going
on
2) We concluded that the electricity must have temporarily stopped
- long enough that the computer, which had no battery, turned
off and went back to the “sign in” screen. With no one to revive
it our data was limited to a 4-hour window

Results
A. The calibration of channel #1 might need to be refined. Results indicated a possible light leak
Experiment:
Experience:
A. The team ended up with challenges that offered us an opportunity to learn:
1. The process for plateauing 4 channels
2. How to use the data feed to determine and resolve a problem with the detector paddle
3. How to write up the non-compliance so that others are aware of non-compliance with our data
4. A list of practical do’s and don’ts when we start the plateauing process again
i. Have a computer with a battery in it so that if the power goes out the battery back up will allow data
to continue to be collected over night
ii. Establishing the initial plateauing number takes about 1.5 hours. Plateauing the remaining paddles
only takes about ½ hour

Discussion and Conclusions
Conclusions:
A. When plateauing channels the first time have support
B. The amount of time it takes to plateauing a channel, especially with the amount of down time that is built into
the process, makes it an after school project for dedicated students not an in class project
C. Researching cosmic rays is an amazing, real-world opportunity for middle and high schools students to add
to science’s body of knowledge. It also offers students a fun way to look at and interact with concepts directly
related to physics
D. Internet research has offered an alternative to the 4 channel tool ($4,000). Given the price ($100) differential
and the source of the information (Massachusetts Institute of Technology [MIT]) it is worth trying
1. http://news.mit.edu/2017/handheld-muon-detector-1121
2. http://cosmicwatch.lns.mit.edu/
3. https://github.com/spenceraxani/CosmicWatch-Desktop-Muon-Detector-v2/blob/master/Instructions.pdf

Bibliography
Abstract
1. Cosmic Rays
a. https://en.wikipedia.org/wiki/Cosmic_ray
i. Cosmic rays are high-energy radiation, mainly originating outside the Solar System and even from distant
galaxies
2. Muons
a. https://en.wikipedia.org/wiki/Muon
i. Muons arriving on the Earth's surface are created indirectly as decay products of collisions of cosmic rays
with particles of the Earth's atmosphere.
ii. About 10,000 muons reach every square meter of the earth's surface a minute; these charged particles
form as by-products of cosmic rays colliding with molecules in the upper atmosphere. Traveling at
relativistic speeds, muons can penetrate tens of meters into rocks and other matter before attenuating as
a result of absorption or deflection by other atoms.
iii. When a cosmic ray proton impacts atomic nuclei in the upper atmosphere, pions are created. These
decay within a relatively short distance (meters) into muons (their preferred decay product), and muon
neutrinos. The muons from these high energy cosmic rays generally continue in about the same direction
as the original proton, at a velocity near the speed of light.
When a cosmic ray proton impacts atomic nuclei in the upper
atmosphere, pions are created. These decay within a relatively
short distance (meters) into muons (their preferred decay product),
and muon neutrinos. The muons from these high energy cosmic
rays generally continue in about the same direction as the original
proton, at a velocity near the speed of light.

Bibliography
Introduction
3. Plateauing
a. reach a state of little or no change after a time of activity or progress
b. a period or state of little or no growth or decline
c. to calibrate/prepare the equipment so that you can conduct an experiment while ensure the validity of your
data
4. Cosmic Ray Muon Detector
a. http://quarknet.fnal.gov/toolkits/ati/crdetectors.html
b. https://www.sciencedaily.com/releases/2017/11/171120174502.htm
c. a tool used to detect/count muons in different environments/locations on earth
5. Voltage
a. https://www.explainthatstuff.com/electricity.html
b. The voltage is a kind of electrical force that makes electricity move through a wire and we measure it in volts.
The bigger the voltage, the more current will tend to flow. So a 12-volt car battery will generally produce
more current than a 1.5-volt flashlight battery.

Bibliography
Introduction
6. Signal rate
a. http://viewpure.com/SNR
b. a measure of signal strength relative to background noise
7. Noise
a. http://cosmic.lbl.gov/documentation/UsingtheDetector.pdf
b. unwanted sounds, interference to the signal you are trying to listen to/hear
8. Channel
a. https://en.wikipedia.org/wiki/Communication_channel
b. a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such
as a radio channel in telecommunications and computer networking

Bibliography
Procedure
9. Multimeter
a. https://www.sciencebuddies.org/science-fair-
projects/references/how-to-use-a-multimeter#qmultimeter
b. http://viewpure.com/MultiMeter
c. A multimeter is a handy tool that you use to measure electricity, just
like you would use a ruler to measure distance, a stopwatch to
measure time, or a scale to measure weight.
i. The neat thing about a multimeter is that unlike a ruler, watch,
or scale, it can measure different things — kind of like a multi-
tool
ii. There are many different multimeter models
10. Noise
a. http://cosmic.lbl.gov/documentation/UsingtheDetector.pdf
b. unwanted sounds, interference to the signal you are trying to listen
to/hear

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