Analysis of neutron diffraction data in the case of high-scattering cells. II. Complex cylindrical cells

Abstract

A new numerical program for the calculation of neutron scattering intensities in a complex cell made of n concentric cylinders has been developed with the purpose of analysing the diffraction data of fluid metals under high-temperature and high-pressure conditions. A simulation of the experiment on liquid Cs at T=1673K and P=86x10 SPa contained in such a cell has been performed in order to test the accuracy of standard data-analysis procedures employed to derive the static structure factor.

Debye to non-Debye scaling of the Boson peak dynamics: Critical behavior and local disorder in vitreous germania

“…The experimental intensity was reduced using Monte Carlo simulation to estimate the multiple scattering, the cell contribution, and the transmission coefficients. 42,43 Spectra were acquired as a function of T, from room temperature to 1000 K. Accessing the supercooled liquid region above 1000 K, besides the typical amorphous pattern, Bragg peaks appeared, thus indicating the start of crystal's nucleation processes. Raman spectra were not affected by this problem since experiments lasted considerably less and the scattering volume was smaller than that in neutron scattering experiments.…”

Real-time observation of the isothermal crystallization kinetics in a deeply supercooled liquid

“…In order to properly evaluate the single scattering intensity of the sample, we collected a set of ancillary measurements including the empty cell, an absorber (a cadmium rod with the same size as the sample container), and the empty beam 35 36 . The empty cell was also used as vanadium standard to normalize data.…”

“…The intensity measured on the PSD detector was reduced to I (2 θ ) using the program ScRiPT provided by LLB. Starting from these data, the properly normalized static structure factor S (2 θ ) was determined via the procedure outlined in refs 35 and 36 . Monte Carlo simulations were exploited to properly estimate the transmission coefficients and the multiple scattering contribution.…”

“…Starting from these data, the properly normalized static structure factor S(2θ) was determined via the procedure outlined in Refs. [31,32]. Monte Carlo simulations were exploited to properly estimate the transmission coefficients and the multiple scattering contribution.…”

“…Data were analyzed according to Refs. [31,32]. The empty cell contribution was not subtracted and Al Bragg peaks were thus included in the analysis.…”