Measurement of the 234U(n, f ) cross-section with quasi-monoenergetic beams in the keV and MeV range using a Micromegas detector assembly

Stamatopoulos, A.; Kanellakopoulos, A.; Kalamara, A.; Diakaki, Μ.; Tsinganis, A.; Kokkoris, M.; Michalopoulou, V.; Axiotis, M.; Lagoyiannis, A.; Vlastou, R.

doi:10.1140/epja/i2018-12429-2

Cited by 5 publications

(3 citation statements)

References 32 publications

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“…In the present work, 234 U and 238 U samples produced at the IPPE (Obninsk) and JINR (Dubna) with the painting technique were used for the fission cross section measurements. They are actinide disks (5 µm thickness, ~ 5.2 cm diameter) deposited on a 100 µm Al backing [10,11]. In the front side of the samples (which is going to be measured with the micromegas detector) aluminum masks were placed (0.6 mm thickness, 5.0 diameter) so that all the samples have the same dimensions (see Fig.…”

Section: Determination Of the Sample Massesmentioning

confidence: 99%

“…Concerning the experimental data for the 234 U(n,f) cross section, several datasets exist in literature, however, for neutron energies between 14 and 18 MeV, there are only 7 datasets [3][4][5][6][7][8][9] that present significant discrepancies (12-60%). Therefore, the purpose of this work was to lessen the aforementioned discrepancies and apart from that, to complete the meauserements of the 234 U(n,f) reaction over a wide energy range by combining the present project with two previous ones published by A. Tsinganis et al [10] and A. Stamatopoulos et al [11]. The final data of the present work have been submitted in the proceedings of the 2019 International Conference On Nuclear Data for Science and Technology (May 19-24 2019, Beijing, China), and they are going to be published on EPJ Web of Conferences during 2020.…”

Section: Introductionmentioning

confidence: 95%

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Measurement of the 234U(n,f) cross section in the energy range between 14.8 and 17.8 MeV using Micromegas detectors

Kalamara

Chasapogloou²,

Michalopoulou³

et al. 2020

hnps

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Neutron induced fission cross sections of actinides present special interest, since they lead to the design optimization of new generation reactors (Generation IV) as well as Accelerator Driven Systems (ADS). In the present work, the 234U(n,f) cross section was measured for which only a few available discrepant data exist in literature leading to poor evaluations. More specifically, four irradiations were performed at the 5.5 MV Tandem Accelerator Laboratory of NCSR “Demokritos” using quasi-monoenergetic neutrons produced by the 3H(d,n)4He reaction in the 14.8-19.2 MeV energy range. The 234U(n,f) cross section was measured relatively to the 235U(n,f) and 238U(n,f) reference ones and in order to perform the in-beam measurements for each of the actinide targets (234U, 238U, 235U), a Micromegas detector was used to record the fission fragments. The target-detector pairs were placed in an Al chamber filled with a Ar:CO2 (in 80:20 volume fraction) gas mixture at atmospheric pressure and temperature. The efficiency of the Micromegas detectors was estimated by Monte-Carlo simulations using the GEF and FLUKA codes. In addition, a detailed study of the neutron energy spectra was carried out by coupling both NeuSDesc and MCNP5 codes in order to take into account and correct for the contribution of low energy parasitic neutrons in the fission yields.

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Section: Determination Of the Sample Massesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Measurement of the 234U(n,f) cross section in the energy range between 14.8 and 17.8 MeV using Micromegas detectors

Kalamara

Chasapogloou²,

Michalopoulou³

et al. 2020

hnps

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“…3. Given this simulated neutron fluence and the evaluated cross section of the 238 U reference target, the reaction rate can be calculated by multiplying the fission cross section with the simulated neutron fluence, following the methodology described in detail in [8] . The ratio of the integrated reaction rate corresponding to the main neutron beam to the total integrated reaction rate, provides the contribution =?9@ of the scattered parasitic neutrons to the recorded fission yield.…”

Section: Fission Yield and Correctionsmentioning

confidence: 99%

Study of the 232Th(n,f) Cross section at NCSR ‘Demokritos’ using Micromegas Detectors

Chasapoglou¹,

Tsantiri²,

Kalamara³

et al. 2020

hnps

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The accurate knowledge of neutron-induced fission cross sections in actinides, is of great importance when it comes to the design of fast nuclear reactors, as well as accelerator driven systems. Specifically for the 232Th(n,f) case, the existing experimental datasets are quite discrepant in both the low and high energy MeV regions, thus leading to poor evaluations, a fact that in turn implies the need for more accurate measurements.In the present work, the total cross section of the 232Th(n,f) reaction has been measured relative to the 235U(n,f) and 238U(n,f) ones, at incident energies of 7.2, 8.4, 9.9 MeV and 14.8, 16.5, 17.8 MeV utilizing the 2H(d,n) and 3H(d,n) reactions respectively, which generally yield quasi-monoenergetic neutron beams. The experiments were performed at the 5.5 MV Tandem accelerator laboratory of N.C.S.R. “Demokritos”, using a Micromegas detector assembly and an ultra thin ThO2 target, especially prepared for fission measurements at n_ToF, CERN during its first phase of operations, using the painting technique. The masses of all actinide samples were determined via α-spectroscopy. The produced fission yields along with the results obtained from activation foils were studied in parallel, using both the NeusDesc [1] and MCNP5 [2] codes, taking into consideration competing nuclear reactions (e.g. deuteron break up), along with neutron elastic and inelastic scattering with the beam line, detector housing and experimental hall materials. Since the 232Th(n,f) reaction has a relatively low energy threshold and can thus be affected by parasitic neutrons originating from a variety of sources, the thorough characterization of the neutron flux impinging on the targets is a prerequisite for accurate cross-section measurements, especially in the absence of time-of-flight capabilities. Additional Monte-Carlo simulations were also performed coupling both GEF [3] and FLUKA [4] codes for the determination of the detection efficiency.

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Empirical formula for (n, f) reaction cross sections of Uranium isotopes at 1–20 MeV neutrons

Abdullah,

Ahmed

2023

Applied Radiation and Isotopes

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Measurement of the 234U(n, f ) cross-section with quasi-monoenergetic beams in the keV and MeV range using a Micromegas detector assembly

Cited by 5 publications

References 32 publications

Measurement of the 234U(n,f) cross section in the energy range between 14.8 and 17.8 MeV using Micromegas detectors

Measurement of the 234U(n,f) cross section in the energy range between 14.8 and 17.8 MeV using Micromegas detectors

Study of the 232Th(n,f) Cross section at NCSR ‘Demokritos’ using Micromegas Detectors

Empirical formula for (n, f) reaction cross sections of Uranium isotopes at 1–20 MeV neutrons

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