Muon Speed Analysis Clara Woods, Kyler Natividad,

Julia Rathmann-Bloch

#phobic_penguins

Overview of Experiment

❖ How fast do muons travel?

❖ How accurately can we measure their speed?

Top Detector

DAQ (Data

Acquisition module)

3 Bottom

Detectors

7 ft + 0.14 ft

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PlateauingWhy do we plateau detectors?

Plateauing detectors is a way of testing if they are functioning correctly as well as finding the perfect setting for optimal use. What we’re looking for is a nice long place where the graph flattens out. As you can see, detector A has an amazing plateau graph, which tells us that it’s working very well. The other three detectors also plateaued, telling us they were legitimate.

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Background research

http://sites.psu.edu/georgecoba/wp-content/uploads/sites/3300/2013/04/Muon-Speed-and-Lifetime.pdfhttp://hep.physics.wayne.edu/web/quarknet/summer/2011/WSUQuarknetSummer2011/studentpresentations/session1/Muon%20Speed%20Study%20(GPS).pptxhttp://www.jurp.org/2012/MS138.pdf

Journal of Undergraduate Research in PhysicsUniversity of Minnesota

Distribution of Muon energies at sea level

WSU Quarknet

Using Excel to analyze data

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HypothesisModel/testable prediction:

Most of the muons will be travelling at the speed of light: c = 3 * 10^8 m/s. We expect a few to have a lower speed. After a preliminary experiment we found data that largely suggests that we will get most of our muons at the speed of light. From our solid angle, we calculated our expected count rate to be about 13.5 per minute. Our original experiment gave us a rough count rate of about 10 + 3 per minute.

Solid Angle of a Pyramid

http://arxiv.org/abs/1205.1396

Analysis Overview1A68F930 BE 00 3C 00 00 00 00 00 198BD108 193048.022 170714 A 12 0 +00721A68F931 00 00 00 00 22 00 24 00 198BD108 193048.022 170714 A 12 0 +00721A68F931 00 3A 00 3E 00 3C 00 39 198BD108 193048.022 170714 A 12 0 +0072277A1655 80 00 00 00 26 00 00 00 26F50B48 193057.014 170714 A 12 0 +0040277A1655 2B 00 28 00 00 00 29 00 26F50B48 193057.014 170714 A 12 0 +0040277A1655 00 00 00 00 00 36 00 00 26F50B48 193057.014 170714 A 12 0 +0040277A1655 00 3E 00 3A 3A 00 00 00 26F50B48 193057.014 170714 A 12 0 +0040277A1656 00 00 00 00 00 27 00 22 26F50B48 193057.014 170714 A 12 0 +0040

Raw Data from DAQ

Quarknet Analysis to getrid of extra information

Speed Analysis

Final Graphs6

Analysis

1A68F930 BE 00 3C 00 00 00 00 00 198BD108 193048.022 170714 A 12 0 +00721A68F931 00 00 00 00 22 00 24 00 198BD108 193048.022 170714 A 12 0 +00721A68F931 00 3A 00 3E 00 3C 00 39 198BD108 193048.022 170714 A 12 0 +0072277A1655 80 00 00 00 26 00 00 00 26F50B48 193057.014 170714 A 12 0 +0040277A1655 2B 00 28 00 00 00 29 00 26F50B48 193057.014 170714 A 12 0 +0040277A1655 00 00 00 00 00 36 00 00 26F50B48 193057.014 170714 A 12 0 +0040277A1655 00 3E 00 3A 3A 00 00 00 26F50B48 193057.014 170714 A 12 0 +0040277A1656 00 00 00 00 00 27 00 22 26F50B48 193057.014 170714 A 12 0 +0040

40 ns timer

Timing data for detector A (1.25 ns resolution)

B C DGPS data, we are not using this

*All used numbers are in hexadecimal

Calculations:𝞓t = t_topdetector - t_bottom detectorv = d/ t𝞓

We set the DAQ to only show us four fold coincidence, meaning that it will ignore an event that does not trigger all four detectors.

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Preliminary Data

Our first day of experiment Three more days of preliminary data to confirm original results

Second peak with a negative time difference (the bottom detector is triggering before the top detector)

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Possible physical explanations for the second peak

Lower-energy backsplash from muon interactions

Hidden source underneath floor

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Ultimate solutionThe resolution is actually 40 ns

The time of each event is found by adding a 40ns clock with a 1.25ns clock. The 1.25ns clock loops every 40ns. Our original analysis used the 40ns clock as a 10ns clock. This caused a -30ns offset when a muon is detected as the 1.25ns clock returns to 0.

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Re-CalibrationDetector A B C D

Average Delay (ns)

0 2.5 .2 3.3

Number of Counts

NA 58831 612320 93670

Error in counts per minute

NA 2.42 .69 1.82

Before we had gotten rid of all false signals and could publish final results, we had to make one more change. We had realized that our detectors were giving us different time delays, so we re-calibrated to get rid of those effects.

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Results

Average speed = 0.968 + 0.009(stat) + .02(systematic) ft/ns

Muon Number vs. Time Difference

c = .984 ft/ns

Additional experiments

~30 ns

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Different edgesFalling edge only Average of falling and

leading edgesLeading edge only

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Threshold data0.400 V Threshold

0.350 V Threshold

We found no difference in precision between different threshold voltages

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Conclusions➢ We found muons traveling at an average speed of .968 ft/ns + .009(stat) + .02(systematic) ft/ns➢ Light travels at a speed of .984 ft/ns➢ The muons we measured were traveling at 98.4% + .9% the

speed of light

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Extension experiments

➔ Shielding to see better spectrum

➔ Change distance for increased precision

➔ Measure which sky angle produces the fastest muons

➔ Speed as a function of altitude

Thank You!

#phobic_penguins

Any Questions?

Many thanks to:

Stuart BriberVicki JohnsonJason NielsonTanmayi SaiBrendan Wells

All our speakers and our fellow interns