The correction of Inelastic Neutron Scattering data of organic samples using the Average Functional Group Approximation

Abstract

The use of the Average Functional Group Approximation for self-shielding corrections at inelastic neutron spectrometers is discussed. By taking triptindane as a case study, we use the above-mentioned approximation to simulate a synthetic dynamic structure factor as measured on an indirect-geometry spectrometer, as well as the related total scattering cross section as a function of incident neutron energy and sample temperature, and the transmission spectra depending on the sample thickness. These quantities, obtained in a consistent way from the Average Functional Group Approximation, are used to calculate the energy-dependent self-shielding correction affecting the sample under investigation. The impact on the intensities of low-energy vibrational modes is discussed, showing that at typical experimental conditions the sample-dependent attenuation factor is about 15% higher compared to the correction at higher energies.

Fluorinated borono‐phenylalanine for optimizing BNCT: Enhancing boron absorption against hydrogen scattering for thermal neutrons

“…The AFGA 21 was developed to provide a simple yet accurate modeling of the thermal neutron scattering cross section of complex polymers (see e.g., Ref. [27]) or large organic molecules, as well as for applications in radiation protection and dosimetry. The model provides a characteristic scattering cross section for hydrogen in each organic functional group.…”

Prospects of spectroscopic neutron imaging: optimizing experimental setups in battery electrolyte research

“…The s T , known as the probability of a neutron interacting with a particular atom, is the sum of the coherent (s elastic coh + s inelastic coh ), incoherent (s elastic inc + s inelastic inc ), and absorption s abs crosssections of each molecule or atom within the sample. 15,16 Therefore, to calculate the s T of H in hydrogenous molecules, all atoms should be taken into account, and eqn (2) is expressed as:…”

“…With these considerations, eqn (1) becomes: T = e − σ T · η i · δ .The σ T , known as the probability of a neutron interacting with a particular atom, is the sum of the coherent ( σ elastic coh + σ inelastic coh ), incoherent ( σ elastic inc + σ inelastic inc ), and absorption σ abs cross-sections of each molecule or atom within the sample. 15,16 Therefore, to calculate the σ T of H in hydrogenous molecules, all atoms should be taken into account, and eqn (2) is expressed as:for i atoms in the molecules constituting the sample. It is important to note that σ T and the measured transmission T depend on the neutron energy.…”