LBL Abstract 2014 - Cosmic Ray Detector Experiments

                          Cosmic Ray Detector Experiments      LBL 2014

Student                                 High School

Teacher                        High School

Purpose –The purpose of this experiment was for students to have hands on experience collecting & interpreting data from muon detectors. All students have had no previous experience using detectors. These detectors were supplied by Howard Matis of LBL.

Methods – After learning how to operate the detector, each of the 10 teams composed of 4 students, 1 teacher & a detector, choose one of the following investigations to determine the rate of flux of muon counts :

1. Tilting the detector between 0 and 90 degrees from the horizontal.
2. Shielding the detector with books, brass, water.
3. Changes in elevation of the detector over a distance of 5 floors.
4. Changing the east west orientation of the detector to determine if the collection were muons or antimuons due to right hand rule of electromagnetism.
5. Showing the angle of scattering by separating the paddles on a gamma source.  This was done by using a particle detector that was made at LBNL through QuarkNet over the last 8 years.

Results  - After collecting data groups returned to the large group to report.

                   Each group gave a presentation of their experimental design & results.

                   The findings are as follows:

1. The data showed the greater the tilt, the lower the flux & at 90 there were almost no counts.
2. There was no difference in flux with most of the materials we were able to use.
3. Groups did find a difference between the basement of the building & the fifth floor.  With the lower locations showing smaller rate of flux.  With group discussion it was determined this was due more to the buildings shielding effect than the small altitude difference.  However we can’t rule out the elevation difference entirely since one group collected data outside underneath a balcony minimizing the shielding .
4. There were 88 more antimuons than muons out of a total count of 1000. A student in the group clearly explained the set up, execution, & physics rules that explained this.
5. The group discovered that if the paddles were not in line at 180 degrees, the count falls off. There was much discussion regarding this experiment regarding the nature of the production of gamma rays.

Meaning & future investigations - Cosmic rays have played a large role in the development of Particle Physics.  The muon as well as antimatter were first detected by cosmic ray investigations.

This activity gave the students a first-hand experience in understanding & working with particles. Working with detectors also helped the students understand the collection of cosmic rays on much larger scales such as in ICECUBE.

Further investigations could include different shielding materials.