Lincoln (Neb.) - March 14, 2000 - Dan Claes flipped the toggle switch on the book-size black box and it immediately began producing tones, some high-pitched, some lower-pitched, sometimes several close together, sometimes spaced a few seconds apart.
What the University of Nebraska-Lincoln assistant professor of physics and astronomy was demonstrating was a cosmic ray detection device. The tones were the impacts of cosmic rays - protons and nuclei of light atoms, "little pieces of stars," Claes said - that constantly bombard Earth from all directions.
The detector is similar to those that he and Greg Snow, an associate professor of physics and astronomy at NU, hope to install at high schools across Nebraska in the next few years, thanks to a $1 million seed grant from the National Science Foundation.
The Cosmic Ray Observatory Project's goal is to install cosmic ray detectors at many of Nebraska's 314 high schools and link them via the Internet in what would be the geographically largest cosmic ray detection network anywhere. Each school's equipment would include a detector to register the impact and energy of cosmic rays, a Global Positioning System device to record the exact time and place of the strikes, and a simple personal computer to keep track of the data and link it to other CROP sites.
A school's science classes will be able to set up their own experiments, but they will also be part of a much larger experiment coordinated by the university.
"In the typical high school science experiment, everything is canned, presented recipe-style and designed to be completed in a 45-minute period," said Claes, a former high school physics teacher. "The answer is sort of predictable, but here, they will actually be part of a long-term, ongoing experiment that, like any real research project, carries no guarantees. They'll learn a little bit about what scientists do, but more importantly, they'll come away with the impression that what scientists do is fun and interesting, and worth pursuing.
"They will be part of an integrated experiment and they will feel like they personally and their school are contributing real, live, useful data to a larger enterprise."
That larger enterprise will be an effort to learn more about two key features of cosmic rays that scientists don't understand - where they come from and how they achieve their high energies.
"Some primaries (single protons) carry the same energy as a driven hockey puck," Claes said. "There is no known phenomenon, not even the supernova explosion of a star, that we believe can drive a proton to that high an energy. Yet they exist, and we don't know where they come from."
When cosmic rays hit molecules in Earth's atmosphere, they create an avalanche of more particles called an 'air shower.' Those particles in turn initiate other collisions that make more and more particles. Eventually millions of particles are hitting Earth's surface.
"The idea is that using a grid of detectors we can intercept a sample of those particles," Snow said. "Based on both counting the number of particles and looking at the relative arrival times of the particles, we can learn something about their original energy and the incident direction of the original particle - whether it's straight above or at an angle. By looking at this debris down on Earth you can sort of reconstruct information about the original particle.
"One of the nice features about our experiment is the detectors are spread out over a much larger geographic region than any of the other major enterprises that are being mounted to study cosmic rays. In a certain way, we have an unprecedented sensitivity to judging whether, say, 'does an area the size of the state of Nebraska light up all at once?' Because of the GPS equipment we'll be able to tell if all the schools detect a big bunch of particles coincidentally."
Thanks to the NSF grant, Snow and Claes are now ready to begin putting CROP in place after brainstorming on it for the last three years. They will be able to fund summer workshops, stipends and expenses for high school teachers and students, a graduate student, a technician, undergraduates doing technical work and purchase of the GPS equipment and computers. They inherited the detectors free of charge from a completed cosmic ray project in Utah.
Snow said the goal after four years is to have a network of 20 to 30
schools in the Lincoln-Omaha area, plus at least one in each of the
state's 19 Educational Service Units to serve as a hub for expanding in
its region. The first group of high schools participating in CROP will
include Lincoln Northeast, the Zoo School in Lincoln, Norfolk and Mount
Michael Benedictine in Elkhorn.
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