The methodology for validation of cross sections in quasi monoenergetic neutron field

• Main Authors: Matěj, Zdeněk, Košťál, Michal, Majerle, Mitja, Ansorge, Martin, Losa, Evžen, Zmeškal, Marek, Schulc, Martin, Šimon, Jan, Štefánik, Milan, Novák, Jan, Koliadko, Daniil, Cvachovec, František, Mravec, Filip, Přenosil, Václav, Zach, Václav, Czakoj, Tomáš, Rypar, Vojtěch, Capote, Roberto
• Format: Journal Article
• Language: English
• Published: 05.06.2023
• Subjects: Physics - Accelerator Physics; Physics - Instrumentation and Detectors; Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.2306.09353

Dosimetry cross sections are fundamental quantities essential in determination of neutron fluences in points of interest in technologies under heavy radiation load. The most common is their application to Reactor Pressure Vessel aging management, relating to correct estimation of its residual lifetime. The neutron spectrum in various reactor positions has a similar character as the fission spectrum. Due to this fact, the validation of the neutron dosimetry cross sections in reactor fields, or in a very well-known neutron field of 252Cf(s.f.) is sufficient for ensuring their validity in estimations of neutron fluxes in reactor physics. With an increasing field of applications, as in neutron dosimetry in accelerator-based fields or space applications, requests occurred on detailed validation in spectra different from fission ones. This paper presents the testing of a new methodology for the use of quasi monoenergetic neutron fields, where different sensitivity allows validations of the cross-section in different energy regions than in the fission spectrum. The exact shape of the neutron spectrum in the tested fields is determined by stilbene spectrometry and corrected to scattering by calculation, where applicable. The total flux is determined from Ni and Al flux monitors. The evaluated neutron flux in the target set of activation foils is used for calculation of theoretical reaction rate, which is compared with the experimental value determined from gamma activity. This kind of comparison can be understood as validation. It is worth noting, this methodology applied to the IRDFF-II library shows satisfactory agreement for selected reactions.