Thermoluminescence of simulated interstellar matter after gamma-ray irradiation

Forsterite, enstatite and carbonates

¹ Faculty of Education, Kagawa University, Takamatsu 760-8522, Japan e-mail: koike@ed.kagawa-u.ac.jp
² Kyoto Pharmaceutical University, Kyoto 607-8412, Japan

³ Research Reactor Institute, Kyoto University, Kumatori 590-0499, Japan

⁴ Department of Earth and Space Science, Osaka University, Toyonaka, Osaka 560-0043, Japan

Corresponding author: K. Koike, koike@ed.kagawa-u.ac.jp

Received: 22 June 2001
Accepted: 9 April 2002

Abstract

Interstellar matter is known to be strongly irradiated by cosmic radiation and several types of cosmic ray particles. Simulated interstellar matter, such as synthesized forsterite (), enstatite () and magnesite (), has been irradiated with gamma-rays in liquid nitrogen, and also irradiated with fast neutrons at 10 K and 70 K by making use of the low-temperature irradiation facility of the Kyoto University Reactor (KUR-LTL. Maximum fast neutron dose is ). After irradiation, samples are stored in liquid nitrogen for several months to allow the decay of induced radioactivity. We measured the luminescence spectra of the gamma ray irradiated samples during warming to 370 K using a spectrophotometer. For the forsterite and magnesite, the spectra exhibit a rather intense peak at about 645–655 nm and 660 nm respectively, whereas luminescence scarcely appeared in the natural olivine sample. The spectra of forsterite is very similar to the ERE of the Red Rectangle.