Building a gamma-ray pair spectrometer for meteorite studies (2016)
Undergraduates: Yuri Tonin, John Dermigny
Faculty Advisor: Christian Iliadis
Department: Physics & Astronomy
Most meteorites were formed about the same time as the planets of the solar system. They travel long distances before falling at surface of the Earth and, during this journey, they are exposed to cosmic radiation. Nuclear reactions happen in the meteoroids due to this energetic radiation, producing radioactive isotopes. Detecting these radioisotopes may provide valuable information on the dating of cosmic ray exposure ages, the constancy of galactic cosmic ray intensity over the past 10 million years, and variations of the solar magnetic field strength over the past few hundred years.
This project intends to build a gamma-ray spectrometer to study meteorites. The construction consists mainly of three stages: first, building the physical apparatus for the system, such as the lead shield for background radiation and setting up gamma-ray detectors. Second, setting up the electronics and programs to perform detector calibration and future data acquisition. Third, simulating the whole system to compare it with real data.
The detection system consists of two identical Thallium-doped Sodium Iodide (NaI(Tl)) scintillators facing each other, with the meteorite being placed between them. Among the reasons for using a pair of detectors is the possibility of performing coincidence measurements, a technique in which room background radiation can be reduced by several order of magnitude.