Cosmic Ray Detector at Work 3 Guys and a Cosmic Ray Detector Derek, Kurt, Doug and Teachers: Josh, Grace

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

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.

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.

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

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.

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.

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.

First Experiment Results

First Experiment Avg. and Error

Second Experiment Between 9:00 a.m. and 10:00 a.m. on August 3 rd 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.

Second Experiment Results

Second Experiment Avg. and Error

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

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.