Neutron production in the lunar subsurface from alpha particles in galactic cosmic rays
Artikel i vetenskaplig tidskrift, 2011

The neutron production from alpha particles in galactic cosmic rays (GCR) in the lunar subsurface has not been estimated with reliable precision despite its importance for lunar nuclear spectroscopy and space dosimetry. Here, we report our estimation of neutron production from GCR nuclei (protons and alpha particles) with the Particle and Heavy Ion Transport code System (PHITS), which includes several heavy ion interaction models. PHITS simulations of the equilibrium neutron density profiles in the lunar subsurface are compared with experimental data obtained in the Apollo 17 Lunar Neutron Probe Experiment. Our calculations successfully reproduced the data within an experimental error of 15%. Our estimation of neutron production from GCR nuclei, estimated by scaling that from protons by a factor of 1.27, is in good agreement within an error of 1% with the calculations using two different alpha particle interaction models in PHITS during a period of average activity of the solar cycle. However, we show that the factor depends on the incident GCR spectrum model used in the simulation. Therefore, we conclude that the use of heavy ion interaction models is important for estimating neutron production in the lunar subsurface.

PHITS

heavy ion transportation

SELENE

lunar and planetary spectroscopy

Neutron

alpha particle

gamma

Moon

ray spectrometer

Författare

S. Ota

Chalmers

Waseda University

National Institute of Radiological Sciences

Shinji Kobayashi

Japan Aerospace Exploration Agency

Lembit Sihver

Chalmers, Teknisk fysik, Nukleär teknik

N. Yamashita

Waseda University

N. Hasebe

Waseda University

Earth, Planets and Space

1343-8832 (ISSN) 1880-5981 (eISSN)

Vol. 63 1 25-35

Ämneskategorier

Subatomär fysik

DOI

10.5047/eps.2010.01.006