Neutron RTOF Stress Diffractometer FSD at the IBR-2 Pulsed Reactor

Abstract

Abstract:The diffraction of thermal neutrons is a powerful tool for investigations of residual stresses in various structural materials and bulk industrial products due to the non-destructive character of the method and high penetration depth of neutrons. Therefore, for conducting experiments in this research field, the neutron Fourier stress diffractometer FSD has been constructed at the IBR-2 pulsed reactor in FLNP JINR (Dubna, Russia). Using a special correlation technique at the long-pulse neutron source, a high resolution level of the instrument has been achieved (∆d/d ≈ 2 ÷ 4 × 10 −3 ) over a wide range of interplanar spacing d hkl at a relatively short flight distance between the chopper and sample position (L = 5.55 m). The FSD design satisfies the requirements of a high luminosity, high resolution, and specific sample environment. In this paper, the current status of the FSD diffractometer is reported and examples of performed experiments are given.

Effect of neutron irradiation on the structure and strength of the SAV-1 aluminum alloy

“…From the analysis of the broadening of diffraction peaks in comparison with the resolution function of the diffractometer, microstrains were determined, averaged over all observed reflections (hkl) (see [12]).…”

“…The measurements were carried out for a series of samples from the SAV-1 aluminum alloy (Table 2). A special correlation technique -using a fast Fourier chopper to modulate the intensity of the primary neutron beam and the RTOF method for data accumulation -allowed to obtain diffraction spectra with high resolution (d/d  210 −3 at a scattering angle of 2 = 140 and d/d  410 −3 at 2 =  90) in a wide range of interplanar spacing, which provides the required accuracy of recording small displacements of diffraction peaks and their broadenings [12,13].…”

Analysis of the Combined Strengthening Effect of Solute Atoms and Precipitates on Creep of Aluminum Alloys

“…Standard Ø8 mm vanadium containers were utilized, and counting times of about 12 h per spectrum were used. All neutron time‐of‐flight (TOF) diffraction experiments were performed on the Fourier stress diffractometer (FSD) at the IBR‐2 pulsed reactor in FLNP JINR (Dubna, Russia) . A special correlation technique at the long‐pulse neutron source, i.e., a combination of the fast Fourier chopper for the primary neutron beam intensity modulation and the reverse time‐of‐flight (RToF) method for data acquisition, was used on FSD.…”

Study of Residual Stresses and Microstructural Changes in Charpy Test Specimens Reconstituted by Various Welding Techniques

“…This gives direct information on changes in interplanar spacing in a gauge volume, which can be easily transformed into data on internal stresses, using known Young's modulus and Poisson's ratio of a material. The experiments were carried out on high-resolution Fourier stress diffractometer (FSD) at the IBR-2 pulsed neutron source in Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research, Dubna, Russia [18]. The FSD diffractometer was specially designed for residual stress studies in bulk industrial components and new advanced materials.…”