scholarly journals Spectroscopy of neutron rich nuclei using cold neutron induced fission of actinide targets at the ILL: The EXILL campaign

2013 ◽  
Vol 62 ◽  
pp. 01001 ◽  
Author(s):  
A. Blanc ◽  
G. de France ◽  
F. Drouet ◽  
M. Jentschel ◽  
U. Köster ◽  
...  
Keyword(s):  
Cold Neutron ◽  
Induced Fission ◽  
Actinide Targets

scholarly journals Spectroscopy of neutron rich nuclei using cold neutron induced fission of actinide targets at the ILL: the EXILL campaign

2014 ◽  
Vol 66 ◽  
pp. 02010 ◽  
Author(s):  
G. de France ◽  
A. Blanc ◽  
F. Drouet ◽  
M. Jentschel ◽  
U. Köster ◽  
...  
Keyword(s):  
Cold Neutron ◽  
Induced Fission ◽  
Actinide Targets

scholarly journals Measurement of the delayed-neutron multiplicity and time constants in the thermal neutron induced fission of 235U at ILL

2020 ◽  
Vol 239 ◽  
pp. 18006
Author(s):  
Daniela Foligno ◽  
Pierre Leconte ◽  
Olivier Serot ◽  
Benoit Geslot ◽  
Grégoire De Izarra ◽  
...  
Keyword(s):  
Data Analysis ◽  
Cold Neutron ◽  
Average Lifetime ◽  
Reactor Safety ◽  
Delayed Neutron ◽  
Delayed Neutrons ◽  
Time Constants ◽  
Experimental Campaign ◽  
Safety Margins ◽  
Induced Fission

Delayed-neutron (DN) data is essential in inherent reactor safety and reactor control since it is needed for the estimation of the reactivity. Nowadays, discrepancies among the data in various international databases (JEFF, ENDF, JENDL) are large and bring excessive conservatism in the safety margins. The ALDEN (Average Lifetime of DElayed Neutrons) experiment, built in a collaboration between CEA and CNRS, aimed at re-measuring the DN data associated with several fissioning systems (average delayed-neutron yield and kinetic parameters). The first experimental campaign consisted in the integral measurement of the DN activity after the irradiation of an 235U target. It took place under the cold neutron flux of ILL (Institut Laue-Langevin) at the beginning of September 2018, in the PF1b experimental zone (doi:10.1016/j.nima.2006.03.020). The data analysis gave an average DN yield of 1.631E-02(2) DN/fiss and a mean precursors’ half-life of 8.93(9) s. The results are consistent with the literature, but they are affected by one third of the uncertainty.

Pion-induced fission of actinide targets

1992 ◽  
Vol 542 (4) ◽  
pp. 511-520 ◽  
Author(s):  
S. de Barros ◽  
I.O. de Souza ◽  
M.B. Gaspar ◽  
R.J. Peterson
Keyword(s):  
Induced Fission ◽  
Actinide Targets

scholarly journals Excited States and Collectivity in 88Se

2018 ◽  
Vol 193 ◽  
pp. 05002
Author(s):  
G. Simpson ◽  
I. Grachev ◽  
G. Thiamova ◽  
M. Ramdhane ◽  
K. Sieja ◽  
...  
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Level Scheme ◽  
Decay Scheme ◽  
Cold Neutron ◽  
Experimental Spectrum ◽  
Quadrupole Deformation ◽  
Model Calculations ◽  
Induced Fission ◽  
Experimental Decay

The γ decays of excited states in the very neutron-rich nucleus 88Se have been observed following the cold neutron-induced fission of 235U at the PF1B facility of the Institut Laue-Langevin (ILL), Grenoble. The EXILL array was used to measure γ - γ - γ coincidences, which were then analysed to build a level scheme of 88Se. A low (2+1) energy hints at the onset of quadrupole deformation and the identification of possible members of a (2+2) band provide evidence for γ vibrations. Shell-model calculations using a 78Ni core reproduce the experimental decay scheme well, implying that interactions between particles in the π f5/2 p and vsd orbits are responsible for much of the collectivity present. The algebraic collective model has also been used to interpret the experimental data, showing that that the experimental spectrum is consistent with 88Se being a transitional nucleus, possessing weak static β deformation and γ instability.

scholarly journals Lifetime measurement around 132Sn with the ν-Ball array

2020 ◽  
Vol 1643 (1) ◽  
pp. 012135
Author(s):  
G Häfner ◽  
R Lozeva ◽  
A Blazhev ◽  
R L Canavan ◽  
D Etasse ◽  
...  
Keyword(s):  
High Resolution ◽  
Fast Neutron ◽  
Scintillation Detectors ◽  
Tandem Accelerator ◽  
Lifetime Measurements ◽  
Fission Fragments ◽  
Hpge Detectors ◽  
Induced Fission ◽  
Γ Ray ◽  
Actinide Targets

Abstract Neutron-rich nuclei were studied after fast neutron-induced fission of 238U and 232Th at the ALTO facility in Orsay, France. The neutrons were produced with the LICORNE directional neutron source using a pulsed 7Li beam provided by the Tandem accelerator. The actinide targets were surrounded by the ν-Ball array to measure the de-excitation of fission fragments. The ν-Ball array is a hybrid spectrometer which consists of HPGe detectors (equipped with BGO shielding) and LaBr3(Ce) scintillation detectors allowing for high-resolution γ-ray spectroscopy and lifetime measurements in the ns/sub-ns range. This contribution presents preliminary results on 134Te and 137I populated in the 238U(n,f) reaction.

Performance of the new cold neutron triple-axis-spectrometer FLEX

1995 ◽  
Vol 213-214 ◽  
pp. 866-868 ◽  
Author(s):  
P. Vorderwisch ◽  
S. Hautecler ◽  
F. Mezei ◽  
U. Stuhr
Keyword(s):  
Cold Neutron

scholarly journals From fission yield measurements to evaluation: status on statistical methodology for the covariance question

2018 ◽  
Vol 4 ◽  
pp. 26 ◽  
Author(s):  
Brieuc Voirin ◽  
Grégoire Kessedjian ◽  
Abdelaziz Chebboubi ◽  
Sylvain Julien-Laferrière ◽  
Olivier Serot
Keyword(s):  
Statistical Tests ◽  
Fission Products ◽  
Experimental Program ◽  
Mass Yield ◽  
Statistical Methodology ◽  
Fission Yield ◽  
Fission Process ◽  
Induced Fission ◽  
Entropy Criterion ◽  
Fission Yields

Studies on fission yields have a major impact on the characterization and the understanding of the fission process and are mandatory for reactor applications. Fission yield evaluation represents the synthesis of experimental and theoretical knowledge to perform the best estimation of mass, isotopic and isomeric yields. Today, the output of fission yield evaluation is available as a function of isotopic yields. Without the explicitness of evaluation covariance data, mass yield uncertainties are greater than those of isotopic yields. This is in contradiction with experimental knowledge where the abundance of mass yield measurements is dominant. These last years, different covariance matrices have been suggested but the experimental part of those are neglected. The collaboration between the LPSC Grenoble and the CEA Cadarache starts a new program in the field of the evaluation of fission products in addition to the current experimental program at Institut Laue-Langevin. The goal is to define a new methodology of evaluation based on statistical tests to define the different experimental sets in agreement, giving different solutions for different analysis choices. This study deals with the thermal neutron induced fission of 235U. The mix of data is non-unique and this topic will be discussed using the Shannon entropy criterion in the framework of the statistical methodology proposed.

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