Detecting Cosmic Rays

 Regents Physics Lab                                                                                                                                       Name:_______________________________________

Title: Detecting Cosmic Rays

This lab is sponsored by Quarknet, a national organization for the exploration of high energy particle interactions with our Earth. QuarkNet provides professional development and on-going support for physics teachers and students.

Video: What are high energy particles? (3-5 mins)

Start Detector - data collection begins without lead - 5 mins

Pre-Lab Discussion:

All day, every day, and every night too, cosmic rays from sources in deep space strike the Earth. Cosmic rays can be of two types. The first is high energy particles such as fast moving protons, and the second is high energy electromagnetic photons. The majority of these rays interact with atoms or molecules in out upper atmosphere and “shatter” those particles into a shower of fragments that then cascades to Earth. Watch the following video for a good representation of such an event.

Link to video

Start Detector - data collection begins with lead shielding - 5 mins

We do not have equipment at school to detect the original cosmic rays, but we do have a particle detector (the CRD or Cosmic Ray Detector) the detects the most prevalent of the shower particles, the Muon.

Video: What is a Muon?

As muons pass through our detectors they deposit some of their energy in the detector the detector responds by “Scintillating” or emitting light. This light is then collected by the photomultiplier tube (PMT) and converted into an electrical pulse. It is those pulses that we collect and analyze.

Discussions of Detector



The purpose of this lab is to discover ways in which to use the CRD to measure various aspects of cosmic ray influx to the Earth and find the various factors that modify that influx.



A Quarknet Cosmic Ray Detector


E-Lab software


Safety For You:

The CRD is powered by 110volt mains current. Be careful what yo touch on the circuit board.

Safety For the Equipment:

Do not put any liquids, food, chemicals etc, near the detector.

Do not pile objects on top of the detector

The detector must remain unplugged and  “powered down” until your setup has been check by your instructor.

Do not pick up the detector panels by the PVC tubes.


Procedure Data Collection: (may be done in your lab groups or by your teacher)

1. Make sure detectors are stacked on top of each other as demonstrated by the teacher

2. Choose one of the experiments below.

3.  Follow the instructions provided to turn the detector on and collect data for that expderiment.

Procedure for analyzing data:

1. Open e-Labs

2. Use the log-in and password provided

3. Data will have been uploaded for you so Click directly on Data

4. Click onFlux

5. Click on menu and select Detector ID

6. Type in 6771 and hit search data

7. Click on arrow next to school name

8. Select the correct date by checking the box to the left of the date

9. Click on Run Flux Study (located on the top right of the page)