On the energy spectrum of cosmogenic neutrons

Abstract

The processes of the generation of cosmogenic neutrons (cg-neutrons) underground are considered. The neutrons produced by cosmic-ray muons in their interactions with matter are called cosmogenic. Deepinelastic πA-collisions of pions in muon-induced hadronic showers are mainly their source at energies above 30 MeV. The characteristics of the energy spectrum for the generation of cg-neutrons have been determined by invoking the additive quark model of deep-inelastic soft processes and the mechanism for the interactions of high-energy nucleons in a nucleus. The three-component shape of the spectrum is explained, and the energy of the "knee" in the spectrum has been found to depend on the mass number A. The peculiarities of deepinelastic πA-scattering lead to the conclusion that the spectrum of cg-neutrons steepens sharply at energies above 1 GeV. The calculated quantitative characteristics of the spectrum are compared with those obtained in measurements.

Nucleation of Supercooled Water by Neutrons: Latitude Dependence and Implications for Cloud Modelling

“…Our recent study [1] held the water supercooled at about −18˚C to −19˚C, suggesting that at −30˚C supercooled water will be significantly more sensitive to the effects of incident neutrons, especially if higher in flux and energy, primarily the former, at higher altitudes [20] [22] [48]. We assume momentum transfer to a nucleus of H or O, pushing the molecule over the energy barrier, as described by classical nucleation theory.…”

“…We assume momentum transfer to a nucleus of H or O, pushing the molecule over the energy barrier, as described by classical nucleation theory. The barrier must be lower at −30˚C and it seems reasonable that incident high-energy neutrons will more efficiently force nucleation [48].…”

Reviewing 39ar and 37ar Underground Production in Shallow Depths with Implications for Groundwater Dating

“…1 Mass Number: A = 22; rock density: ρ r = 2.65 g cm −3 (Malgin, 2015) Even though most fast muon-induced neutrons are emitted with energies in the MeV range, their energy spectrum extends up to hundreds of GeV (Wang et al, 2001;Garrison, 2014;Palermo, 2016;Malgin, 2017). Generally, the energy distribution of these neutrons is uncertain since measuring energy spectra over a wide range is a complex task, and simulating the physical processes involved in neutron production from muons requires sophisticated models.…”

“…The uncertainties of these parameters propagate through the production calculations. In the last decades, models have been proposed and discussed in the literature for the description of the flux and energy spectra of muons and neutrons in the subsurface for instance (Stone et al, 1998;Braucher et al, 2003;Mei and Hime, 2006;Malgin and Ryazhskaya, 2008;Malgin, 2017;Ludwig et al, 2019).…”

“…Muons are cosmogenic secondary particles penetrating deeper than neutrons and capable of inducing nuclear reactions up to depths of several hundreds of meters (Aglietta et al, 1999;Braucher et al, 2003;Mei and Hime, 2006;Malgin and Ryazhskaya, 2008;Alfimov and Ivy-Ochs, 2009;Malgin, 2017;Kneißl et al, 2019). Muons were recently identified as significant contributors to 39 Ar underground production by the muon capture reactions on potassium [ 39 K(μ − ,γ) 39 Ar] in the context of Dark Matter research in deep underground laboratories (Mei and Hime, 2006).…”