Pushing the high count rate limits of scintillation detectors for challenging neutron-capture experiments

One of the critical aspects for the accurate determination of neutron capture cross sections when combining time-of-flight and total energy detector techniques is the characterization and control of systematic uncertainties associated to the measuring devices. In this work we explore the most conspicuous effects associated to harsh count rate conditions: dead-time and pile-up effects. Both effects, when not properly treated, can lead to large systematic uncertainties and bias in the determination of neutron cross sections. In the majority of neutron capture measurements carried out at the CERN n\_TOF facility, the detectors of choice are the C$_{6}$D$_{6}$ liquid-based either in form of large-volume cells or recently commissioned sTED detector array, consisting of much smaller-volume modules. To account for the aforementioned effects, we introduce a Monte Carlo model for these detectors mimicking harsh count rate conditions similar to those happening at the CERN n\_TOF 20~m fligth path vertical measuring station. The model parameters are extracted by comparison with the experimental data taken at the same facility during 2022 experimental campaign. We propose a novel methodology to consider both, dead-time and pile-up effects simultaneously for these fast detectors and check the applicability to experimental data from $^{197}$Au($n$,$\gamma$), including the saturated 4.9~eV resonance which is an important component of normalization for neutron cross section measurements

Advances and new ideas for neutron-capture astrophysics experiments at CERN n_TOF

This article presents a few selected developments and future ideas related to the measurement of (n,γ) data of astrophysical interest at CERN n_TOF. The MC-aided analysis methodology for the use of low-efficiency radiation detectors in time-of-flight neutron-capture measurements is discussed, with particular emphasis on the systematic accuracy. Several recent instrumental advances are also presented, such as the development of total-energy detectors with γ-ray imaging capability for background suppression, and the development of an array of small-volume organic scintillators aimed at exploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics prospects related to the intermediate i neutron-capture process of nucleosynthesis are discussed in the context of the new NEAR activation area

Advances and new ideas for neutron-capture astrophysics experiments at CERN n_TOF

This article presents a few selected developments and future ideas related to the measurement of (n,γ) data of astrophysical interest at CERN n_TOF. The MC-aided analysis methodology for the use of low-efficiency radiation detectors in time-of-flight neutron-capture measurements is discussed, with particular emphasis on the systematic accuracy. Several recent instrumental advances are also presented, such as the development of total-energy detectors with γ-ray imaging capability for background suppression, and the development of an array of small-volume organic scintillators aimed at exploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics prospects related to the intermediate i neutron-capture process of nucleosynthesis are discussed in the context of the new NEAR activation area

Neutron inelastic cross section measurements on 58,60Ni

A natural nickel sample was used at the GELINA (Geel Electron LINear Accelerator) neutron source of the European Commission, Joint Research Centre, Geel to measure the neutron inelastic cross sections. The GAINS (Gamma Array for Inelastic Neutron Scattering) spectrometer was employed to detect the emitted gamma rays while a 235U fission chamber monitored the neutron flux. We report the preliminary production cross sections corresponding to the first transitions in 58,60Ni in comparison with previously reported data and with TALYS 1.9 calculations performed using the default input parameters.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

GAINS: neutron inelastic cross section measurements of interest for applications and reaction studies

The paper represents an overview of the measurements performed using GAINS at GELINA (JRC-Geel, Belgium). While undergoing continuous upgrades, the setup produced highly precise cross sections. Our measurements are primarily driven by technological needs with an emphasis on structural materials used in the development of nuclear facilities. However, most cases offered the opportunity to investigate various reaction mechanism and/or nuclear structure issues. We concentrate on several specific experiments describing the particular difficulties we met and the solutions we adopted to infer reliable data and to draw significant conclusions

Neutron inelastic scattering on 54^{54}Fe

International audienceA neutron inelastic scattering experiment was performed at the Geel Electron Linear Accelerator neutron source using an enriched$^{54}$Fe sample. The $\gamma$ rays produced in the reaction were detected using the Gamma Array for Inelastic Neutron Scattering spectrometer. For each observed transition we determined the $\gamma$ -production cross section for incident energies ranging from the inelastic threshold ( $\approx 1.434$ MeV) up to 18 MeV. Using these primary data we also calculated the cross section of the first excited level and the total inelastic cross section. Our experimental results are compared with previous reported values, evaluated nuclear data libraries and theoretical calculations performed with the TALYS 1.9 code. A careful tuning of the optical model parameters allowed significant improvements in the description of the experimental results leading to interesting conclusions regarding the interaction of the$^{54}$Fe nucleus with neutrons

GAINS: neutron inelastic cross section measurements of interest for applications and reaction studies

International audienceThe paper represents an overview of the measurements performed using GAINS at GELINA (JRC-Geel, Belgium). While undergoing continuous upgrades, the setup produced highly precise cross sections. Our measurements are primarily driven by technological needs with an emphasis on structural materials used in the development of nuclear facilities. However, most cases offered the opportunity to investigate various reaction mechanism and/or nuclear structure issues. We concentrate on several specific experiments describing the particular difficulties we met and the solutions we adopted to infer reliable data and to draw significant conclusions

GAINS: neutron inelastic cross section measurements of interest for applications and reaction studies

The paper represents an overview of the measurements performed using the GAINS spectrometer at the GELINA neutron source at JRC-Geel in Belgium. The setup produced over the years highly precise cross sections while undergoing continuous upgrades. Our measurements are primarily driven by technological needs with an emphasis on structural materials used in the development of nuclear facilities. However, most cases offered the opportunity to investigate various reaction mechanism and/or nuclear structure issues. The second part of the paper concentrates on several specific experiments describing the particular difficulties we met and the solutions we adopted to infer reliable data and to draw significant conclusions.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

High precision neutron inelastic cross section measurements

International audienceHigh precision neutron inelastic scattering cross section data are very important for the development of the new generation of nuclear reactors (Gen IV). Our experiments, performed using the GELINA neutron source and the GAINS spectrometer of the European Commission Joint Research Center, Geel, produce highly reliable and precise cross section data. We will present the details of the setup and the data analysis technique allowing production of such unique results, and we will show examples of two experimental results

Neutron inelastic scattering on 54Fe

A neutron inelastic scattering experiment was performed at the Geel Electron Linear Accelerator neutron source using an enriched 54Fe sample. The gamma rays produced in the reaction were detected using the Gamma Array for Inelastic Neutron Scattering spectrometer. For each observed transition we determined the gamma-production cross section for incident energies ranging from the inelastic threshold (1.434 MeV) up to 18 MeV. Using these primary data we also calculated the cross section of the first excited level and the total inelastic cross section. Our experimental results are compared with previous reported values, evaluated nuclear data libraries and theoretical calculations performed with the talys 1.9 code. A careful tuning of the optical model parameters allowed significant improvements in the description of the experimental results leading to interesting conclusions regarding the interaction of the 54Fe nucleus with neutrons.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard