Radioisotope studies of the farmville meteorite using γγ-coincidence spectrometry

Chris Howard; Megan Ferm; John Cesaratto; Stephen Daigle; Christian Iliadis

doi:10.1016/j.apradiso.2014.07.001

Radioisotope studies of the farmville meteorite using γγ-coincidence spectrometry

Appl Radiat Isot. 2014 Dec:94:23-29. doi: 10.1016/j.apradiso.2014.07.001. Epub 2014 Jul 10.

Authors

Chris Howard¹, Megan Ferm², John Cesaratto¹, Stephen Daigle¹, Christian Iliadis³

Affiliations

¹ Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA.
² Keene State College, Keene, NH 03435, USA.
³ Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA. Electronic address: iliadis@unc.edu.

PMID: 25063942
DOI: 10.1016/j.apradiso.2014.07.001

Abstract

Radionuclides are cosmogenically produced in meteorites before they fall to the surface of the Earth. Measurement of the radioactive decay of such nuclides provides a wealth of information on the irradiation conditions of the meteorite fragment, the intensity of cosmic rays in the inner solar system, and the magnetic activity of the Sun. We report here on the detection of (26)Al using a sophisticated spectrometer consisting of a HPGe detector and a NaI(Tl) annulus. It is shown that modern γ-ray spectrometers represent an interesting alternative to other detection techniques. Data are obtained for a fragment of the Farmville meteorite and compared to results from Geant4 simulations. In particular, we report on optimizing the detection sensitivity by using suitable coincidence gates for deposited energy and event multiplicity. We measured an (26)Al activity of 48.5±3.5dpm/kg for the Farmville meteorite, in agreement with previously reported values for other H chondrites.

Keywords: (26)Al; Farmville meteorite; Monte Carlo simulations; γ-ray spectrometry.