Cosmic Ray Detector at Work

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Cosmic Ray Detector at Work

• 3 Guys and a Cosmic Ray Detector
• Derek, Kurt, Doug and Teachers Josh, Grace

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What are Cosmic Rays?

• Subatomic particles from outer space, the exact
  location is still unknown
• These particles interact with our atmosphere and
  form cosmic ray showers
• Cosmic Ray detectors can detect these showers on
  Earth

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The Cosmic Ray Detector

• A particle from the cosmic ray shower (muons)
  strikes the scintillator and forms a photon of
  light.
• This photon of light is detected by the
  photomultiplier, which then converts it to an
  electric signal.
• The amount of electric signals per minute was
  recorded.

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Purpose and Hypothesis

• Purpose To better understand cosmic rays and how
  they are detected.
• Hypothesis Increasing the amount of concrete
  will deflect or absorb more cosmic rays resulting
  in fewer detected cosmic rays per minute.

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Materials

• Cosmic ray detector to measure counts per minute
• Parking garage
• 12 V. power source (a car)
• Tape measure to measure thickness of concrete
• Clock to time 1 minute

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Procedure

• Using the Shaw parking structure, starting from
  the roof and working to the ground floor, each
  floor was detected for the amount of cosmic rays
  present. In relatively the same location on each
  floor the cosmic rays were counted for a total of
  one minute per trial. Four trials were conducted
  on each floor, to increase the accuracy of the
  results.

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First Experiments Woes

• Our first attempt at gathering data was met with
  systematic error. When recording data on the
  roof, the CRD was giving strange results. The
  amount of cosmic rays after every trial on the
  roof consistently dropped.

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First Experiment Woes Cont.

• Another detector was tested on the roof to
  determine whether or not the detector used in the
  trials was faulty. The results of the second
  detector also showed a decline in cosmic rays
  over time. We believe that the hot weather and
  heavy amount of sunlight caused the detector to
  overheat, resulting in faulty data on the roof.

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First Experiment Results
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First Experiment Avg. and Error
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Second Experiment

• Between 900 a.m. and 1000 a.m. on August 3rd
  the experiment was repeated. The weather was cool
  and cloudy which should allow the detector to
  achieve accurate readings on the roof.
• Again a similar location on each floor was tested
  for cosmic rays present for one minute. Four
  trials on each of the five floors were performed.

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Second Experiment Results
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Second Experiment Avg. and Error
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Systematic Errors

• The cars in the garage may have deflected cosmic
  rays or even shield the detector from potential
  cosmic rays
• The weather and particularly the heat caused the
  CRD to overheat and give inaccurate readings on
  the roof

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Conclusion

• With the data obtained, it can be determined that
  increasing the amount of concrete did deflect or
  absorb more cosmic rays resulting in fewer
  detected cosmic rays per minute.
• The error was significant but a conclusion could
  be found.