Journal of Neutron Research - Volume 18, issue 1

Article Type: Editorial

DOI: 10.3233/JNR-150021

Citation: Journal of Neutron Research, vol. 18, no. 1, pp. 1-1, 2015

Authors: Lander, Gerard H. | Steiner, Michael

Article Type: Research Article

Abstract: After an Introduction on the history of nuclear fission, we re-examine the scientific relationship between Otto Hahn and Lise Meitner in view of a number of newly published articles in the last two decades. We find the evidence overwhelming that they should have shared the Nobel Prize – rather than it being awarded to Hahn alone. In the post-war period Hahn’s actions are often difficult to understand, but we find no compelling evidence that he acted dishonourably.

Keywords: Fission, Hahn, Meitner

DOI: 10.3233/JNR-150018

Citation: Journal of Neutron Research, vol. 18, no. 1, pp. 3-12, 2015

Authors: Rivin, Oleg | Shaked, Hagai | Gukasov, Arsen | Caspi, El’ad N.

Article Type: Research Article

Abstract: Polarized neutron powder diffraction technique is extended to the case of uni-axial, high anisotropy (hard) magnetic materials. The experimental considerations of this technique are discussed and an appropriate analysis is developed.

Keywords: Polarized neutron powder diffraction, anisotropic magnetic materials, flipping difference

DOI: 10.3233/JNR-140015

Citation: Journal of Neutron Research, vol. 18, no. 1, pp. 13-20, 2015

Authors: Mamontov, Eugene

Article Type: Research Article

Abstract: We propose a modification of the neutron wide-angle velocity selector (WAVES) device that enables inelastic (in particular, quasielastic) scattering measurements not relying on the neutron time-of-flight. The proposed device is highly suitable for a steady-state neutron source, somewhat similar to a triple-axis spectrometer, but with simultaneous selection of the incident and final neutron energy over a broad range of scattering momentum transfer. Both the incident and final neutron velocities are defined by the WAVES geometry and rotation frequency. The variable energy transfer is achieved through the natural variation of the velocity of the transmitted neutrons as a function of the …scattering angle component out of the equatorial plane. Show more

Keywords: Quasielastic neutron scattering, inelastic neutron scattering, instrumentation

DOI: 10.3233/JNR-150019

Citation: Journal of Neutron Research, vol. 18, no. 1, pp. 21-28, 2015

Authors: Liu, Weibo | Li, Mingjuan | Gao, Kun | Gu, Deshan

Article Type: Research Article

Abstract: An explosive detection system based on the pulsed fast thermal neutron analysis (PFTNA) is developed. The 14 MeV D–T pulsed neutron generator, console, bismuth germanate (BGO) detector, main amplifier, gate circuit and 4096 multichannel analyzer (MCA) are applied in this system. The neutron collimator and shielding device are also designed to reduce the unnecessary external interference and improve the detection efficiency. Using the system, the explosive mimic (urea) is detected and identified by calculating the ratio of hydrogen atoms to oxygen atoms (H/O). The influence of detection conditions, such as detection distance and sample mass, to the experimental results is investigated. …It shows that, when the high voltage of main amplifier is 755 V, the count rate is 4000 n/s, the sample is placed as close as possible to the bottom of the neutron generator, and the sample mass is more than 800 g, the sample can be distinguished well by comparing the H/O ratio. It is confirmed that the explosives can be detected by the detection system, which provides a new method for detecting explosives. Show more

Keywords: Pulsed fast thermal neutron analysis, explosives detection, γ ray spectrum, detection conditions

DOI: 10.3233/JNR-150020

Citation: Journal of Neutron Research, vol. 18, no. 1, pp. 29-34, 2015