scholarly journals Cross section measurement of 241Am(n,f) reaction at the Experimental Area 2 of the n_TOF facility at CERN: First Results

2020 ◽  
Vol 27 ◽  
pp. 189
Author(s):  
Zinovia Eleme ◽  
... Et al.
Keyword(s):  
Cross Section ◽  
Nuclear Waste ◽  
Energy Production ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Β Decay ◽  
Experimental Area ◽  
High Production Rate ◽  
First Results ◽  
Set Up

The condition for the safe design and operation of fast neutron reactors and energy boosters (Generation-IV reactors, ADS systems [1]) is the accuracy of nuclear data. The 241Am isotope (T1/2 = 433 years) is highly present in nuclear waste, accounting for about 1.8% of the actinide mass in PWR UOx nuclear reactors’ waste [2]. In addition, the 241Am isotope is further produced by the β decay of the 241Pu isotope (T1/2 = 14.3 years). Given the high production rate of 241Am isotope, its incineration with concurrent energy production is considered to be of utmost importance for the design and implementation of the recycling of existing nuclear waste. Sensitivity studies of the proposed systems for energy production showed that high-precision measurements of the cross section of the 241Am(n,f) reaction are required. In the present work, the 241Am(n,f) reaction cross section was measured in the Second Experimental Area of the n_TOF facility at CERN, using an array of Micromegas detectors. For the measurement, six targets of 241Am with average activity of 17 MBq per sample were coupled with an equal number of detectors in a common chamber. Additionally two 235U and two 238U samples were coupled with Micromegas detectors utilizing the neutron flux determination. Within this work, an overview of the experimental set-up and the adopted data analysis technique is presented along with preliminary results.

scholarly journals First results of the 241Am(n,f) cross section measurement at the Experimental Area 2 of the n_TOF facility at CERN

2020 ◽  
Vol 239 ◽  
pp. 05014
Author(s):  
Z. Eleme ◽  
N. Patronis ◽  
A. Stamatopoulos ◽  
A. Tsinganis ◽  
M. Kokkoris ◽  
...  
Keyword(s):  
Cross Section ◽  
Nuclear Waste ◽  
Reaction Cross ◽  
Section Data ◽  
Experimental Area ◽  
First Results ◽  
Sensitivity Studies ◽  
High Level Nuclear Waste ◽  
High Level

Feasibility, design and sensitivity studies on innovative nuclear reactors that could address the issue of nuclear waste transmutation using fuels enriched in minor actinides, require high accuracy cross section data for a variety of neutron-induced reactions from thermal energies to several tens of MeV. The isotope 241Am (T1/2= 433 years) is present in high-level nuclear waste (HLW), representing about 1.8 % of the actinide mass in spent PWR UOx fuel. Its importance increases with cooling time due to additional production from the β-decay of 241Pu with a half-life of 14.3 years. The production rate of 241 Am in conventional reactors, including its further accumulation through the decay of 241Pu and its destruction through transmutation/incineration are very important parameters for the design of any recycling solution. In the present work, the 241 Am(n,f) reaction cross-section was measured using Micromegas detectors at the Experimental Area 2 of the n_TOF facility at CERN. For the measurement, the 235U(n,f) and 238U(n,f) reference reactions were used for the determination of the neutron flux. In the present work an overview of the experimental setup and the adopted data analysis techniques is given along with preliminary results.

A NEW SET-UP FOR TOTAL REACTION CROSS SECTION MEASURING

Exotic Nuclei ◽  
2013 ◽  
Author(s):  
YU. G. SOBOLEV ◽  
M. P. IVANOV ◽  
A. KUGLER ◽  
YU. E. PENIONZHKEVICH
Keyword(s):  
Cross Section ◽  
Reaction Cross Section ◽  
Reaction Cross ◽  
Total Reaction Cross Section ◽  
Total Reaction ◽  
Set Up

New empirical formula for calculating (n,p) reaction cross-sections at 14.5MeV neutrons

2020 ◽  
Vol 29 (08) ◽  
pp. 2050052
Author(s):  
Dashty T. Akrawy ◽  
Ali H. Ahmed ◽  
E. Tel ◽  
A. Aydin ◽  
L. Sihver
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Empirical Formula ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Section Data ◽  
Nuclear Data Library ◽  
Number Formula ◽  
New Formula ◽  
Reaction Cross Sections

An empirical formula to calculate the ([Formula: see text], [Formula: see text] reaction cross-sections for 14.5[Formula: see text]MeV neutrons for 183 target nuclei in the range [Formula: see text] is presented. Evaluated cross-section data from TENDL nuclear data library were used to test and benchmark the formula. In this new formula, the nonelastic cross-section term is replaced by the atomic number [Formula: see text], while the asymmetry parameter-dependent exponential term has been retained. The calculated results are presented in comparison with the seven previously published formulae. We show that the new formula is significantly in better agreement with the measured values compared to previously published formulae.

scholarly journals A BGO set-up for the direct measurement of the D(p,γ)3He fusion cross section at LUNA

2020 ◽  
Vol 1668 (1) ◽  
pp. 012028
Author(s):  
Viviana Mossa
Keyword(s):  
Cross Section ◽  
Cosmic Time ◽  
Fusion Cross Section ◽  
Big Bang ◽  
Baryon Density ◽  
Reaction Cross ◽  
Big Bang Nucleosynthesis ◽  
Primordial Abundance ◽  
Set Up ◽  
The Big Bang

Abstract The Big Bang Nucleosynthesis (BBN) describes the production of light nuclides occurred during the first minutes of cosmic time. It started with the accumulation of deuterium, whose primordial abundance is sensitive to the universal baryon density and to the amount of relativistic particles. Currently the main source of uncertainty to an accurate theoretical deuterium abundance evaluation is due to the poor knowledge of the D(p, γ)3He cross section at BBN energies. The present work wants to describe one of the two experimental approaches proposed by the LUNA collaboration, whose goal is to measure with unprecedented precision, the reaction cross section in the energy range 30 < Ecm[keV] < 300.

Neutron Field Shaping Using Graphite for Reaction Rate Measurements

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Mikita Sobaleu ◽  
Michal Košťál ◽  
Jan Šimon ◽  
Evžen Losa
Keyword(s):  
Cross Section ◽  
Reaction Rate ◽  
Nuclear Data ◽  
Data File ◽  
Reaction Rates ◽  
Reaction Cross ◽  
Neutron Field ◽  
Pure Graphite ◽  
24Na Reaction ◽  
Data Libraries

Abstract Neutron field shaping is the suitable method for validation of cross section in various energy regions. By increasing the share of neutrons of a certain energy interval and decreasing the share of other, a reaction becomes more sensitive to selected neutrons. As a result, reaction cross section can be validated in selected energy regions more precisely. The shaping can be carried out by both neutron filters which are materials with high absorption in some energy region, or by diffusion material changing the shape of neutron spectra by means of slowing down process. In the presented experiments, the neutron field of the light reactor 0 (LR-0) research reactor was shaped by both using graphite blocks inserted into the core and Cd cladding for increasing the epithermal reaction rate share in total reaction rates. The calculations were carried out with the Monte Carlo N-Particle Transport Code 6 (MCNP6) code and the most recent nuclear data libraries. The results in the pure graphite neutron field are in good agreement; in case of Cd cladding, significant discrepancies were reported. In case of the 23Na(n,γ)24Na reaction, overestimation by about 14% was reached in International Reactor Dosimetry and Fusion File (IRDFF-II), results in other libraries are comparable. In case of 58Fe(n,γ)59Fe, the overestimation as high as 18% is reported in IRDFF-II. For 64Zn(n,γ)65Zn reasonable agreement was reached in evaluated nuclear data file (ENDF/B-VIII), where discrepancies in pure graphite neutron field or in case of Cd cladding are about 10–15%.

scholarly journals First Results of the 140Ce(n,γ)141Ce Cross-Section Measurement at n_TOF

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 200
Author(s):  
Simone Amaducci ◽  
Nicola Colonna ◽  
Luigi Cosentino ◽  
Sergio Cristallo ◽  
Paolo Finocchiaro ◽  
...  
Keyword(s):  
Cross Section ◽  
Globular Clusters ◽  
Liquid Scintillator ◽  
Nuclear Data ◽  
P Wave ◽  
Accurate Analysis ◽  
Significant Difference ◽  
Experimental Apparatus ◽  
First Results ◽  
Scintillator Detectors

An accurate measurement of the 140Ce(n,γ) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the 140Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in 140Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the 140Ce Maxwellian-averaged cross-section.

scholarly journals Neutron reaction studies in the rare earth region: First results for the 162Er(n,2n)161Er physics case

2019 ◽  
Vol 22 ◽  
pp. 45
Author(s):  
N. Patronis ◽  
X. Aslanoglou ◽  
M. Axiotis ◽  
Z. Eleme ◽  
V. Foteinou ◽  
...  
Keyword(s):  
Rare Earth ◽  
Experimental Method ◽  
Cross Section ◽  
Reaction Cross Section ◽  
Reaction Cross ◽  
Activation Technique ◽  
Reaction Study ◽  
Neutron Reaction ◽  
First Results ◽  
Threshold Energies

In the present work the first experimental results at near two threshold energies for the 162Er(n,2n)161Er reaction study are presented. The reaction cross section was determined at the energies of 11.0 and 11.3 MeV by means of the activation technique. The experimental method and setup is described.

scholarly journals Preparation and characterization of 10B targets at JRC-Geel

2020 ◽  
Vol 229 ◽  
pp. 03005
Author(s):  
David Vanleeuw ◽  
Jan Heyse ◽  
Goedele Sibbens ◽  
Mariavittoria Zampella
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Time Of Flight ◽  
Fission Cross Section ◽  
Nuclear Data ◽  
Areal Density ◽  
Reaction Cross ◽  
Neutron Time

Measurements of neutron-induced cross sections to generate nuclear data are a core activity of the JRC-Directorate G Standards for Nuclear Safety, Security and Safeguards unit in Geel. Thin 10B layers are of great importance in this activity as they are used to measure the absolute neutron flux in the beam using the standard 10B(n,α)7Li reaction cross-section as a reference. After a period of reduced activity and in line with a renewed interest for nuclear data, the demand for high quality 10B targets increased. In this paper we describe the design and features of a new e-beam evaporator specifically customized for the preparation of boron targets as replacement of the old dysfunctional equipment. Several 10B targets of varying thicknesses were prepared and characterized as part of the factory acceptance tests and implementation in the JRC-Geel target preparation laboratory. Differential substitution weighing was applied for mass determination and in order to calibrate the thickness monitor. Comparative time-of-flight measurements relative to 10B and 235U standard targets were conducted at the GELINA neutron time-of-flight facility at the JRC-Geel site as second methodology for the determination of 10B areal density. The morphology of the layers was assessed by means of Scanning Electron Microscopy (SEM). The determination of impurities was realized by means of Energy Dispersive X-ray (EDX). Finally, two boron targets were prepared in the frame of the measurement of the neutron induced fission cross-section of 230Th at the n_TOF neutron time-of-flight facility at CERN.

scholarly journals Measurement of the240Pu(n,f) cross-section at the CERN n_TOF facility: First results from experimental area II (EAR-2)

2017 ◽  
Vol 146 ◽  
pp. 04030 ◽  
Author(s):  
A. Stamatopoulos ◽  
A. Tsinganis ◽  
N. Colonna ◽  
R. Vlastou ◽  
M. Kokkoris ◽  
...  
Keyword(s):  
Cross Section ◽  
Experimental Area ◽  
First Results
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