What do you do if you have 18 Geiger tubes lying around? [Robert] had an interesting idea to build a cosmic ray detector and hodoscope to observe the path cosmic rays take while flying through his lab.
[Robert]‘s cosmic ray detector works by detecting the output 9 Geiger tubes on the y-axis and 9 Geiger tubes on the x-axis with a coincidence circuit. When a cosmic ray flies through the detector, it should trigger two tubes simultaneously. By graphing which of the two tubes were triggered on an array of 81 LEDs, [Robert] not only knows when a cosmic ray is detected, but where the cosmic ray was.
The detectors do pick up a little background radiation, but thanks to [Robert]‘s coincidence circuit, he can be fairly certain that what he’s recording are actually high-energy cosmic rays.
Before building the 9×9 hodoscope, [Robert] built a similar drift hodoscope that simply plots the path a cosmic ray takes through an array of Geiger tubes. You can check out videos of both these cosmic ray detectors after the break.