An alternative methodology for high counting-loss corrections in neutron time-of-flight measurements

Stamatopoulos, A.; Diakaki, Μ.; Tsinganis, A.; Colonna, N.; Gunsing, F.; Tassan‐Got, L.; Kokkoris, M.; Kalamara, A.; Žugec, P.; Patronis, N.; Sabaté-Gilarte, M.; Vlastou, R.

doi:10.1016/j.nima.2018.10.032

Cited by 5 publications

(9 citation statements)

References 25 publications

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“…To address such issues that could not be accommodated by analytical expressions found in literature, a new correction methodology was recently developed which is based on exponential decay fits of waiting time distributions, reconstructed in time-of-flight regions where the reaction rate is considered constant, and on the use of detector emulation devices [185]. Fig.…”

Section: Dead-time Correctionmentioning

confidence: 99%

“…An alternative approach, described in Ref. [185], is to use sophisticated signal generators to emulate the detector signals during the experiment and feed them to the acquisition system for a wide bandwidth of frequencies (true counting rate, R true ) in order to cover the measured counting rates in the experiment (experimental counting rate, R exp ). The ratio between the true and experimental counting rates f DT for each given frequency provides a correction function calculated by fitting the experimental points with a parabolic function, as can be seen in Fig.…”

Section: Dead-time Correctionmentioning

confidence: 99%

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The fission experimental programme at the CERN n_TOF facility: status and perspectives

et al. 2020

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Neutron-induced fission reactions play a crucial role in a variety of fields of fundamental and applied nuclear science. In basic nuclear physics they provide important information on properties of nuclear matter, while in nuclear technology they are at the basis of present and future reactor designs. Finally, there is a renewed interest in fission reactions in nuclear astrophysics due to the multi-messenger observation of neutron star mergers and the important role played by fission recycling in r -process nucleosynthesis. Although studied for several decades, many fundamental questions still remain on fission reactions, while modern applications and the development of more reliable nuclear models require high-accuracy and consistent experimental data on fission cross sections and other fission observables. To address these needs, an extensive fission research proa gramme has been carried out at the n_TOF neutron timeof-flight facility at CERN during the last 18 years, taking advantage of the high energy resolution, high luminosity and wide energy range of the neutron beam, as well as of the detection and data acquisition systems designed for this purpose. While long-lived isotopes are studied on the 185 m long flight-path, the recent construction of a second experimental area at a distance of about 19 m has opened the way to challenging measurements of short-lived actinides. This article provides an overview of the n_TOF experimental programme on neutron-induced fission reactions along with the main characteristics of the facility, the various detection systems and data analysis techniques used. The most important results on several major and minor actinides obtained so far and the future perspectives of fission measurements at n_TOF are presented and discussed.

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Section: Dead-time Correctionmentioning

confidence: 99%

Section: Dead-time Correctionmentioning

confidence: 99%

The fission experimental programme at the CERN n_TOF facility: status and perspectives

et al. 2020

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“…3 and 5) signals with systematically higher amplitudes were reconstructed, which is attributed to pile-up effects. The analytical methods used below 1 MeV were not able to provide realistic corrections, therefore a new methodology was developed [45] to treat such cases based on two approaches: (a) exponential decay fits in experimental waiting time distributions as shown in Fig. 9 and (b) correction functions predicted from detector emulation devices.…”

Section: Counting Lossesmentioning

confidence: 99%

“…For the uranium samples the correction function described in Ref. [45] was used. The correction factors that were calculated with a 3% uncertainty did not exceed 1.62 and 1.31 for 235 U and 238 U, respectively.…”

Section: Counting Lossesmentioning

confidence: 99%

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Investigation of the Pu240(n,f) reaction at the n_TOF/EAR2 facility in the 9 meV–6 MeV range

Stamatopoulos¹,

Tsinganis²,

Colonna³

et al. 2020

Phys. Rev. C

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Background: Nuclear waste management is considered amongst the major challenges in the field of nuclear energy. A possible means of addressing this issue is waste transmutation in advanced nuclear systems, whose operation requires a fast neutron spectrum. In this regard, the accurate knowledge of neutron-induced reaction cross sections of several (minor) actinide isotopes is essential for design optimization and improvement of safety margins of such systems. One such case is 240 Pu, due to its accumulation in spent nuclear fuel of thermal reactors and its usage in fast reactor fuel. The measurement of the 240 Pu(n, f) cross section was previously attempted at the CERN n_TOF facility EAR1 measuring station using the time-of-flight technique. Due to the low amount of available material and the given flux at EAR1, the measurement had to last several months to achieve a sufficient statistical accuracy. This long duration led to detector deterioration due to the prolonged exposure to the high α activity of the fission foils, therefore the measurement could not be successfully completed. Purpose: It is aimed to determine whether it is feasible to study neutron-induced fission at n_TOF/EAR2 and provide data on the 240 Pu(n, f) reaction in energy regions requested for applications. Methods: The study of the 240 Pu(n, f) reaction was made at a new experimental area (EAR2) with a shorter flight path which delivered on average 30 times higher flux at fast neutron energies. This enabled the measurement to be performed much faster, thus limiting the exposure of the detectors to the intrinsic activity of the fission foils. The experimental setup was based on microbulk Micromegas detectors and the time-of-flight data were analyzed with an optimized pulse-shape analysis algorithm. Special attention was dedicated to the estimation of the non-negligible counting loss corrections with the development of a new methodology, and other corrections were estimated via Monte Carlo simulations of the experimental setup. Results: This new measurement of the 240 Pu(n, f) cross section yielded data from 9 meV up to 6 MeV incident neutron energy and fission resonance kernels were extracted up to 10 keV. Conclusions: Neutron-induced fission of high activity samples can be successfully studied at the n_TOF/EAR2 facility at CERN covering a wide range of neutron energies, from thermal to a few MeV.

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Advanced algorithms for retrieving pileup peaks of digital alpha spectroscopy using antlions and particle swarm optimizations

El_Tokhy

2020

NUCL SCI TECH

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An alternative methodology for high counting-loss corrections in neutron time-of-flight measurements

Cited by 5 publications

References 25 publications

The fission experimental programme at the CERN n_TOF facility: status and perspectives

The fission experimental programme at the CERN n_TOF facility: status and perspectives

Investigation of the Pu240(n,f) reaction at the n_TOF/EAR2 facility in the 9 meV–6 MeV range

Advanced algorithms for retrieving pileup peaks of digital alpha spectroscopy using antlions and particle swarm optimizations

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