HiSparc educational cosmic ray detector

HiSparc (English-language site) links secondary schools across Europe with professional astronomers and physicists to study cosmic rays. The students build networked cosmic ray detectors that they mount on the roofs of their schools. The data flow into the project’s archives, letting professional astronomers study high-energy cosmic rays.

The fusion reactions in the core of supergiant stars create all of the elements in the periodic table until they get to iron. The star’s massive pressure can’t fuse iron atoms which leads to the core’s collapse and triggers a supernova explosion. The intense shockwaves create all of the elements more massive than iron and blasts the material away from the newly-forming neutron star. Some of the material accelerates to near-light speeds. When these atomic nuclei, called cosmic rays, collide with other matter they release more energy than any particle accelerator on Earth. One of the main radiation risks in deep space travel comes from cosmic rays. As the nucleus of iron or other element crashes into a spaceship’s metallic hull, it unleashes a blast of radiation that disables electronic circuitry and increases astronauts’ risk of cancer.

Cosmic ray research lets astronomers learn about supernovae. It’s also an important part of high-energy physics research. Particle accelerators such as the Large Hadron Collider only produce a fraction of the energy that cosmic ray collisions release. But there’s a catch. The atmosphere blocks cosmic rays. That makes life possible on our planet’s surface, but it forces scientists to take an indirect approach. When a cosmic ray smashes into an atom in the atmosphere the collision unleashes a burst of sub-atomic particles that collide with other atoms and release more particles. The atmosphere absorbs most of the energy. All we can detect on Earth’s surface is a shower of muons spread out across a large region. Scientists deploy regional sensor networks to detect the muons. Like forensic analysts at a crime scene, they reconstruct the collision so they can reach conclusions about the original cosmic ray. Enlisting schools lets the scientists achieve many goals at the same time. They deploy a large regional network without the expense that comes with leasing land, supplying power, or linking to communications satellites. Just as important, the scientists help the schools teach science in a more interesting, hands-on way that gets students interested in pursuing science and engineering careers.

Scientists at the Netherland’s National Institute for Subatomic Physics developed an inexpensive subatomic particle detector that produces scientifically useful results. The shower of subatomic particles strike a scintillator that converts the particle’s energy into photons. Photomultipliers detect the light and amplify the signal. The detector consists of two scintillator/photomultipliers separated by one meter to ensure that it only detects cosmic ray showers. Data from a GPS receiver logs the data and lets the central server synchronize each school’s report. The data flow into the HiSparc Public Archive where anyone can access the data for their own research. The HiSparc team also produces API’s to let virtual observatory apps search the archive’s metadata. JavaScript libraries and Python libraries let scientist develop their own code to download and analyze the cosmic ray data.

The HiSparc program engages the students as if they were the principle investigators. The students assemble and install the detector on the school’s roof. The students monitor the data for quality control and to maintain the detector. The students write their own software in JavaScript or Python to download and analyze their data. Since 2003, the HiSparc program has grown to over one hundred observing stations across the Netherlands. British schools joined the HiSparc program in 2012. The University of Bristol helps students at half a dozen schools conduct their own research and contribute to professional science.

You can read an early paper describing HiSparc presented at the 29th International Cosmic Ray Conference in 2005. At the time the network only had thirty-five observing stations but had already detected a cosmic ray particle collision one million times more powerful than those produced in the Large Hadron Collider.