Journal of Neutron Research - Volume 23, issue 4

Authors: Arai, Masatoshi | Andersen, Ken H. | Argyriou, Dimitri N. | Schweika, Werner | Zanini, Luca | Harjo, Stefanus | Kamiyama, Takashi | Harada, Masahide

Article Type: Research Article

Abstract: The general performance of diffractometers at the first long pulse spallation source ESS, is compared with their counterparts at J-PARC, a short pulse spallation source. The difference in the inherent pulse structure of these neutron sources presents opportunities for new concepts for instrumentation, where performance does not scale simply with source power. The article describes advantages and disadvantages of those diffractometers, adapting to the very different source characteristics. We find that the two sources offer comparable performance in flux and resolution when operating in high-resolution mode. ESS offers significant advantages in tunability and flexibility, notably in the ability to relax …resolution in order to increase flux for a given experiment. The slow repetition rate of ESS favors long instruments. On the other hand, J-PARC instruments perform very well in spite of the lower source power and allow better access to epithermal neutrons, of particular interest for PDF analysis of diffraction data. Show more

Keywords: ESS, J-PARC, source, diffractometer, instrument, performance

DOI: 10.3233/JNR-200180

Citation: Journal of Neutron Research, vol. 23, no. 4, pp. 215-232, 2021

Authors: Zorn, Reiner

Article Type: Research Article

Abstract: In quasieleastic neutron scattering spectrometers one usually faces a trade-off between energy resolution and counting statistics. If the resolution is improved the intensity at the detectors reduces and vice versa. It is not immediately clear how to weigh both factors against each other. In this paper it is proposed to use the maximum time obtainable by Fourier transform of the spectra as the quantity to be optimised. It is shown that this leads to a well-defined criterion for the choice of the resolution.

Keywords: Quasielastic neutron scattering, neutron spectroscopy, experimental design, instrumental resolution

DOI: 10.3233/JNR-210029

Citation: Journal of Neutron Research, vol. 23, no. 4, pp. 233-242, 2021

Authors: Kruglov, V.V. | Balagurov, A.M. | Belova, M.O. | Bobrikov, I.A. | Bogdzel, A.A. | Bodnarchuk, V.I. | Bulavina, V.V. | Daulbaev, O. | Drozdov, V.A. | Zhuravlev, V.V. | Kirilov, A.S. | Kulikov, S.A. | Kurilkin, A.K. | Milkov, V.M. | Murashkevich, S.M. | Podlesnyy, M.M. | Prikhodko, V.I. | Churakov, A.V. | Shvetsov, V.V.

Article Type: Research Article

Abstract: The high-resolution Fourier diffractometer (HRFD) operates at the IBR-2 pulsed reactor, on which the correlation method of data registering has been implemented using a fast Fourier chopper and specialized electronics. A wide-aperture ring back-scattering detector for HRFD has been developed. The detector consists of six Z n S ( A g ) / 6 L i F -scintillation rings, each one of which is divided into 12 sections. Main parameters of this detector: covered solid angle 2 θ = ( 133 − 175 ) ∘ ; Ω d …≈ 2.0 sr; average absorption efficiency 85 % , geometric contribution to resolution Δ d / d < 0.0005 . The concept of a detector and its data acquisition system are presented. Show more

Keywords: Neutron diffraction, neutron detectors, detector electronics

DOI: 10.3233/JNR-210001

Citation: Journal of Neutron Research, vol. 23, no. 4, pp. 243-250, 2021

Authors: Klimko, S. | Legendre, F. | Longeville, S.

Article Type: Research Article

Abstract: The Orphée reactor, located at the CEA Saclay near Paris, that was used to produce neutrons for scattering experiments over the past four decades has been stopped definitively in October 2019. The Laboratoire Léon Brillouin, the laboratory that operated the diffractometers and spectrometers around the Orphée reactor, is studying the possibility to build a compact Neutron Source to keep offering neutron beams to the French neutron scattering community. The efficient use of a pulsed source requires neutron instrumentation using Time-of-Flight (TOF) principles.The transfer of NSE spectrometer from continuous to pulse source requires the change of monochromatic neutron beam spin-echo technique …to the TOF one. Here we report a successful attempt of adaptation of the Neutron Resonance Spin-Echo spectrometer MUSES (G1bis) to a pulsed source with a frequency of 20 Hz and a duty cycle of roughly 5 % . Show more

Keywords: Neutron resonance spin-echo, pulsed neutron source, TOF

DOI: 10.3233/JNR-210003

Citation: Journal of Neutron Research, vol. 23, no. 4, pp. 251-265, 2021