Cosmic Rays for Environmental Sensing (CRES)


The Cosmic Watch Muon Detector v2 detects the cosmic rays, muons. The cost for the first cosmic ray detector for muons was about $250, while muon detectors used in nuclear research at Oregon State University costed an estimated $25,000. Cosmic Rays for Environmental Sensing (CRES) will use the Cosmic Watch v2 as a base for developing a gamma ray detector, high and low energy neutron detectors. The motivation for CRES is to develop a cheaper variety of detectors to aid environmental science research by removing barriers like cost, and special certifications.

There are two avenues of research for CRES. During the first half of 2019 the focus of CRES will be developing a gamma ray detector to get the water content in a snow patch. The water content is found by seeing how much the snow patch has reduced the intensity of the constant gamma rays from the rocks. Summer of 2019 the neutron detectors designed by a visiting researcher, Nick van de Giessen of TU Delft’s water department, will begin to be built while he visits. The purpose of him building his high and low energy neutron detectors is to get the soil moisture for a 100-meter radius by taking the ratio of high to low energy neutrons.

Environmental Physics Motivation

Cosmic rays produce a flash of particles and electromagnetic energies. When the rays reach earth’s surface they interact with matter; detection these cosmic rays reveals valuable information about the environment.

water molecules in snow absorb gamma rays


In the mountains rocks considered non-radioactive give off constant gamma rays for the location. When snow falls on these rocks, the water molecules in the snow absorb some of the gamma rays which is exemplified in the image to the right.

Beer’s law is applied to calculate the maximum water content of the snow for forecasting. The equation used is: I(snow) = I(initial) × exp(α×Z). Where I is intensity of the waves, α is the attenuation coefficient, and Z is the path length or distance of the medium; which in this case Z will be the water content of the snow. With a gamma ray detector the only unknown variable we will have is the path length, so the equation is rearranged to be: Z = -ln( I(snow)/I(initial) ) × 1/α.

Soil MOISTURE found by neutron energy ratio

Neutrons have an atomic mass of 1, and start off with a high energy level. In the air above earth neutrons collide into other subatomic particles and elements which causes them to bounce around in the atmosphere, this bouncing around is called atmospheric scattering. Due to the mass of neutrons most of their collisions are inelastic which results in little energy loss. When a neutron collides with a hydrogen atom in a water molecule, it goes from high to low energy; this is called thermalization. Hydrogen causes energy loss to the neutron is because it also has an atomic mass of 1 which results in an inelastic collision. By obtaining the ratio of high to low energy neutrons we will know the the soil moisture for a 100 meter radius.

general muon detection applications

Muon detectors used in series together form a muon telescope, which is used for mapping out areas like caves, Egyptian Tombs, and to aid safe urban development.


  • Modify Cosmic Watch to detect gamma rays, and prevent other cosmic rays from interfering with gamma ray data.

  • Make use of scintillators to transform the Cosmic Watch to detect neutrons.

  • Work with the Radiation Detection Group at Oregon State to implement and to test our equipment against theirs to ensure ours is working accurately.



In process




Muon, Gamma Ray, Neutrons, Detection, Arduino Nano, Cosmic Watch v2, scintillators, Water Density Sensing.



  • [1] “ARDUINO NANO–CHINA,” Sri Lakshmi Electronics, 01-Aug-2018.