Cosmic Ray Detector Experiments LBL 2015


 Katherine Arackaparambil

Jessica Bartling

Camille Beards

Joseph Bohan

Violet Castle

Matthew Chin

Noel Chou

Kayla Dempsey

Reina Garay-Solis

Marina Gee

David Glover

Hsiao Tung Ho (Daniel)

Yifan Hong

Kelly Hong

Jillian Johns

Manan Khattar


Ivan Kudriavtcev

Thomas Kilkenny

Kristina Macaluso

Nina Medernach

Michael Mueller

Helena Poolos

Samuel Rapp

Reed (Samuel) Sandbach

Yasmin Shamloo

Andrew Siler

Kathlynn Simotas

Nathan Sunbury

Mikaela Torretta

Quynh Tran (Wendy)

Alexander Wang

LeeAnn Wang

Tao Wang (Michael Kwan)

Woodrow Wang

Nicolas Ryan Williams

Yuling Wu (Yvonne)

Matthew  Yeh

wenting zhang

Belinda Zhen

Bao Zhong  (Anna)

Bernice Zhu


Teacher                        High School

Ray Adams


Miles Chen

Bay School SF

Craig Eldred

Terra Linda

Sean Fottrell

Castro Valley

Burke Green


Laura Guthrie


Jane Kelson


Bryan Marten


Glen Melnik


Richard Piccioni

Bay School SF

Theresa Summer

Woodside International

Amber Zertuche





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 4 teams composed of 10 students, 2 teachers & a detector, choose one of the following investigations to determine the rate of flux of muon counts tilting the detector between 0 and 90 degrees from the horizontal.

There was a 5minute experiment of the paddles orientated horizontally, a 5 minute experiment of the paddles orientated vertically, and a 5 minute experiment orientated at approximately 45 degrees.


Data -   Orientation of paddles    Detector #1       Detector #2       Detector #3      Detector #4


                   Horizontal                       100                    78                 103                    78


  Min.         Vertical                             23                     12                  23                      9


                  45 degrees                         70                      18                 72                     34


                   Shielding                         N/A                   N/A               87                     79      



Results  -  The data of each detector was written on the board & analyzed.  We discussed what causes the difference of these counts depending upon the orientation in a given detector.  Each group saw there was a much higher count when the paddles were orientated horizontally as opposed to vertically.  By seeing this difference it gave us confidence that we were detecting muons and not just electrical noise. There was also a discussion on why the two detectors had different counts. Then there was a detailed explanation on how voltage plays a role in the sensitivity of the paddles.  Too high of a voltage gives a runaway count, too low of a voltage gives no count.  Another detector was used to demonstrate when different voltages were applied to the paddles showing the difference of sensitivity to muon count. 



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 subatomic particles on much larger scales such as in Sno+.

Further investigations could include different shielding materials, different elevations of detection, and different orientations such as East & West.