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(n, p) transmutations in the silicon nitride (Si₃N₄) nanoparticles by the neutrons at different energies have been studied by computer simulation. The transmutations by neutrons in the nanomaterial were separately investigated for silicon and nitrogen atoms in the Si₃N₄ particles. Since the effective cross-section of the possible probability of transmutation is different in the various types of silicon and nitrogen atoms, the modeling was performed separately for each stable isotope. The spectra of the effective cross-sections of the (n, p) transmutations for silicon and nitrogen atoms have been studied in relation to each other.

The thermal neutron capture cross-section of ${}^{164}$Dy(n,$\gamma$)${}^{165}$Dy and half-life of ${}^{165}$Dy was determined using Neutron Activation Analysis technique. The Dy target has been irradiated by neutron using Am-Be neutron source at MCNS, MAHE, Manipal, India. Using HPGe detector, the gamma ray spectrum of the irradiated sample has been measured. The half-life of ${}^{165}$Dy was calculated to be $140\pm 1$min. The neutron flux distribution data from the most recent study in Ref. 12, based on the same Am-Be neutron source facility, have been used to calculate the thermal neutron cross-section of ${}^{165}$Dy. The thermal neutron capture cross-section is determined to be $2008\pm 220$ barns which is in good agreement with the recent measurement in Ref. 10 using neutron diffraction facility.

One important component of the ambient background in underground laboratories are neutrons, which cover a wide energy range from thermal up to 100 MeV. After a few meters rock overburden, cosmic-ray neutrons are a negligible contribution underground and the remaining flux is due to neutron production by cosmic-ray muons and by (α,n) reactions from natural radioactivity in the rock.

There are only a few measurements of the full spectral neutron flux available in the literature, a fact which hampers comparisons between laboratories and negatively affects the planning of future experiments.

In an effort to overcome this issue a setup consisting of six moderated and one unmoderated ³He neutron counters that has been used at a depth of 850 m in the Canfranc underground laboratory, Spain [1], was utilized to study the neutron flux in the 48 m deep Dresden Felsenkeller underground laboratory, Germany. At Felsenkeller, an additional counter with a lead liner was used in order to address also the high-energy flux up to several hundreds of MeV.