Improvements in Antineutrino Detector Response by Including Fission Product Isomeric Transitions and Corrections using New Data

TL;DR

This paper enhances antineutrino spectrum modeling by incorporating fission product isomeric transitions and corrections, significantly improving detector response predictions for CEvNS sensors using new data and correction methods.

Contribution

It introduces the inclusion of isomeric transition corrections and updated fission product libraries in antineutrino spectrum modeling, improving accuracy of CEvNS detector response predictions.

Findings

Isomeric transition correction increases spectrum values by 29-37%.

Corrected spectra lead to a 37% increase in detector response.

Finite size and other corrections have minimal impact (<3.27%).

Abstract

CEvNS detectors could provide new opportunities in nuclear physics applications if they can improve existing parameters such as neutrino detector size, portability, their sensitivity to a large range of reactor antineutrino energies, and resources required for operation. Thus, modelling the antineutrino spectrum is a crucial step to study the reactor antineutrino spectra and the CEvNS detector response. The first objective of this paper is to study the importance of fission product libraries in the construction of antineutrino spectrum using the summation method and with various corrections. We have used ENDF/B-VIII and JEFF3.3 as our base data to model the spectrum. We have also included the TAGS data (pandemonium free) when such data is available. The isomeric transitions correction has the highest impact on the antineutrino spectra increasing the values 29% to 37% on an average in the energy range of 0.5 MeV to 2 MeV. This correction also shows an increase of 4.71% to 7.13% in the range of 0 to 2 MeV, with improving isomeric transitions using the TAGS data. Next, the spectra including the isomeric transition correction using the Gross Theory causes reduction by 11.56 % to 69.46 % in the range of 6 to 8 MeV. The finite size, radiative, and weak magnetism corrections cause no more than 3.27% difference between the corrected and uncorrected spectra. Our second objective is to calculate pulse height distributions of Ge and Si based CEvNS sensors assuming a 20eV nuclear recoil threshold. In our study, we have assumed a 100kg detector placed 10m away from the 1MW TRIGA reactor. Our results show that the detector response with corrected spectra for a natural Ge and Si detector are 44.25events/day and 7.99events/day. The biggest impact on the detector response is due to the isomeric transition correction; with 37% difference between the corrected and uncorrected detector response is observed.