Principles of reverse neutron time-of-flight spectrometry with fourier chopper applications

Pöyry, Heikki; Hiismäki, Pekka; Virjo, A.

doi:10.1016/0029-554x(75)90707-7

Cited by 30 publications

(6 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It may be the correlation spectroscopy with pseudo-random flux modulation [25][26][27][28][29][30][31][32][33] or Fourier spectroscopy with periodic or quasiperiodic flux modulation [34][35][36][37][38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

Time-of-flight Fourier UCN spectrometer

Kulin

Frank

Goryunov

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

We describe a new time-of-flight Fourier spectrometer for investigation of UCN diffraction by a moving grating. The device operates in the regime of a discrete set of modulation frequencies. The results of the first experiments show that the spectrometer may be used for obtaining UCN energy spectra in the energy range of 60÷200 neV with a resolution of about 5 neV. The accuracy of determination of the line position was estimated to be several units of 10 −10 eV

show abstract

Section: Introductionmentioning

confidence: 99%

Time-of-flight Fourier UCN spectrometer

Kulin

Frank

Goryunov

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

show abstract

“…In the pseudo-random method the beam intensity is modulated with a periodic binary pseudo-random signal (Fig.1A) and the time of flight spectrum is calculated as the cross-correlation of the modulation signal and the detector output [2]. The Fourier diffractometer involves modulation of the neutron beam by a fast Fourier chopper [3][4][5][6][7] (Fig.1B) which is a rotating disk (rotor) with a pattern of alternating neutron absorbing and neutron transparent slits; and a fixed system of identical slits (stator). The method consists of measuring the Fourier transform of the TOF spectrum at several discrete frequencies and forming the spectrum itself by Fourier synthesis from the measured frequency components.…”

Section: Introductionmentioning

confidence: 99%

A Time-Delayed Neural Network Model for Neutron TOF Spectrum Measurements

Khalil¹

2011

IJCTE

View full text Add to dashboard Cite

Abstract-A novel approach for performing the reverse time of flight (RTOF) analysis of the diffraction spectra through the use of time-delayed neural network (TDNN) is introduced. The new design applies a data acquisition system, a special interface card and software program installed in a PC computer, to perform the cross-correlation functions between signals received from the chopper-decoder and detector devices. This paper focuses on theoretical analysis of the neural network architecture to be embedded in the data acquisition system. The implementation of the suggested TDNN along with the experimental measurements will be deferred to a subsequent paper.

show abstract

“…The main idea of the RTOF method is to examine the registration probability (high or low) for detected neutrons [5]. This is realized by the reverse analysis of "open" and "closed" states of the neutron source and Fourier chopper for each detector event.…”

Section: Fsd Diffractometer At the Ibr-2 Pulsed Reactormentioning

confidence: 99%

“…The average residual strain was determined as ε = (a − a 0 )/a 0 , where a is the lattice parameter for the studied specimen with residual stresses and a 0 is the lattice parameter for stress-free reference material. The residual stress components were determined from the obtained strain values according to Equation (5). In the investigated specimen, the distribution of the residual stress tensor components over scan coordinate X alternate in sign and vary within wide limits (Figure 14b).…”

Section: Welding Residual Stressesmentioning

confidence: 99%

“…These attempts were rather unsuccessful due to the insufficient accuracy and stability of the chopper rotation. In 1975, a new correlation method for detecting scattered neutrons, reverse time-of-flight (RTOF), was proposed [5] and successfully realized on the first RTOF Fourier diffractometer ASTACUS [6] at the FiR-1 250 kW TRIGA-reactor in the VTT Technical Research Centre (Espoo, Finland). This achievement stimulated the construction of two more Fourier diffractometers at steady state reactors: mini-SFINKS for structural investigations in PNPI (Gatchina, Russia) [7] and FSS for residual stress studies in GKSS (Geesthacht, Germany) [8,9].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Bokuchava

2018

Crystals

View full text Add to dashboard Cite

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.

show abstract

Principles of reverse neutron time-of-flight spectrometry with fourier chopper applications

Cited by 30 publications

References 9 publications

Time-of-flight Fourier UCN spectrometer

Time-of-flight Fourier UCN spectrometer

A Time-Delayed Neural Network Model for Neutron TOF Spectrum Measurements

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

Contact Info

Product

Resources

About