scholarly journals Neutron spectrometry and dosimetry in 100 and 300 MeV quasi-mono-energetic neutron field at RCNP, Osaka University, Japan

2017 ◽  
Vol 153 ◽  
pp. 08020 ◽  
Author(s):  
Vladimir Mares ◽  
Sebastian Trinkl ◽  
Yosuke Iwamoto ◽  
Akihiko Masuda ◽  
Tetsuro Matsumoto ◽  
...  
2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Evžen Losa ◽  
Michal Košťál ◽  
Milan Štefánik ◽  
Jan Šimon ◽  
Tomáš Czakoj ◽  
...  

Abstract This work aims to characterize the neutron spectrum in the beam going out of the university research reactor (VR-1) using tubular-type of the nuclear fuel, version 4M (IRT-4M) fuel. Thanks to its variability, the core is often rearranged to fulfill different research tasks. Measurements with new core configuration have been carried out to confirm the spectrum shape in the neutron beam of the radial channel remains unchanged even though the core has been rearranged. Based on this finding, the VR-1 can be considered as a mockup for other IRT-4M fueled reactors, even with higher power. The neutron spectrum stability has been proven by measurement and by comparison of measurements done on the C12 and C13 cores. Fast neutron spectrum in the channel has been evaluated by means of neutron spectrometry by scintillation detector and activation materials (Au, Co, Ni, Al, Fe, and NaI). If the neutron field stability is proven, the radial channel beam can be used for evaluation of spectrum weighted cross section disregarding changes in the core configuration. Assuming reactions with higher threshold, their rates can be compared with rates obtained in the pure prompt fission neutron spectrum (PFNS), since earlier measurements have shown that the neutron spectrum in the light water reactor cavity is equal to the PFNS above 6 MeV threshold. Result 1.1831 mb for 127I(n,2n) reaction evaluated from the VR-1 activation measurement demonstrates good agreement of the measured reaction rate with tabulated rate averaged in 235U PFNS, confirming the neutron spectrum stability and equality to the PFNS.


2020 ◽  
Vol 239 ◽  
pp. 20004
Author(s):  
Dusan Kral ◽  
Miroslav Zeman ◽  
Karel Katovsky ◽  
Elmira Melyan ◽  
Robert Holomb

Threshold activation detectors (TAD) are of great importance for a determination of neutron energy spectra and flux density. For different sources, it is necessary to choose the right combination of materials that cover the estimated spectra. Several different materials were irradiated in a quasi-monoenergetic neutron field with 29.1 MeV peak neutrons energy in the CANAM facility. Neutrons were produced in p + Li-7 reaction in a thin target and the foils were situated in the proton beam axis and close geometry to the Li target. The integral number of protons was established from accelerator telemetry and lithium target activation measurements after the experiment. During the experiment, one long irradiation was done for following foils: Al, Au, Bi, Co, Cu, Fe, In, Mn, Pb, Ta, V, Y and four short irradiations for foils: Cu, Fe, In, Ta, V, W, Y. The foils were irradiated in a sandwich configuration, sorted by cross-section where the materials with higher cross-section were placed in the back of the sandwich. Neutrons produced in the p + Li-7 reaction have a quasi mono-energetic spectrum which provides a suitable basis for cross-section determination. Experimental results were calculated for (n,xn), (n,p) and (n,α) reactions via the dosimetry foils activation method including a gamma-ray spectroscopy method. Several important spectroscopic corrections have to be applied to increase the accuracy of the obtained results, including neutron background suppression. Experimental data will be submitted to the EXFOR database.


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