Measurement of the muon-induced neutron flux at LNGS with the LVD experiment
Persiani, Rino <1980>
Subject
FIS/04 Fisica nucleare e subnucleare
FIS/01 Fisica sperimentale
Description
In this thesis we describe in detail the Monte Carlo simulation (LVDG4) built
to interpret the experimental data collected by LVD
and to measure the muon-induced neutron yield in iron
and liquid scintillator.
A full Monte Carlo simulation, based on the Geant4 (v 9.3) toolkit, has been
developed and validation tests have been performed.
We used the LVDG4 to determine the active vetoing and the
shielding power of LVD. The idea was to evaluate the feasibility to
host a dark matter detector in the most internal part, called
Core Facility (LVD-CF). The first
conclusion is that LVD is a good moderator, but the iron supporting structure
produce a great number of neutrons near the core. The second conclusions
is that if LVD is used as an active veto for muons, the neutron flux
in the LVD-CF is
reduced by a factor 50, of the same order of magnitude of the neutron flux
in the deepest laboratory of the world, Sudbury.
Finally, the muon-induced neutron yield has been measured.
In liquid
scintillator we found $(3.2 \pm 0.2) \times 10^{-4}$
n/g/cm$^2$, in agreement with previous measurements performed at different
depths and with the general trend predicted by theoretical calculations
and Monte Carlo simulations.
Moreover we present the first measurement, in our knowledge,
of the neutron yield in iron:
$(1.9 \pm 0.1) \times 10^{-3}$ n/g/cm$^2$. That measurement provides an
important check for the MC of neutron production in heavy materials that are
often used as shield in low background experiments.
Persiani, Rino (2011) Measurement of the muon-induced neutron flux at LNGS with the LVD experiment, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Fisica , 23 Ciclo. DOI 10.6092/unibo/amsdottorato/3897.