Speaker
Description
The 124Sn nucleus is used in several large scale experiments searching for neutrinoless double beta (0νββ) decay [1-7]. Accurate capture cross section data in 124Sn are essential for understanding (and subtracting based on simulations) the neutron-induced background in this kind of rare-event experiments [6-11]. The thermal neutron capture cross section on this isotope is expected to play a critical role as these experiments are performed deep underground where important fluxes of thermal neutrons are present [11]. As current experimental data display very large discrepancies at the thermal region [12], clarifying this background component is one of the essential steps towards proving the feasibility of such large scale (and thus very expensive) experiments.
However, the existing data in the resolved resonance region (RRR), up to 10 keV, are sparse and inconsistent across major evaluated libraries (ENDF, JEFF, JENDL), largely due to reliance on activation measurements at thermal energies and/or time-of-flight (TOF) data with very short flight paths, both lacking detailed resonance structure [12].
A new measurment was performed in Experimental area 2 (EAR2) of the neutron time-of-flight facility n_TOF at CERN [13] to address the need for improving the neutron capture data on 124Sn. The measurement was done using the nine sTED detectors array [14-15]. During the talk we will present the experimental technique and the main steps of the data analysis employed to extract preliminary results. Emphasis will be given to the data analysis challenges encountered due to the very high neutron flux specific to EAR2 coupled to an unfavourable elastic-to-capture ratio for this nucleus: dead time and pile up corrections, background subtraction, multiple scattering corrections for thick samples, etc.
Acknowledgment:
This work has received funding from the European Union’s Horizon Europe Research and Innovation programme, EURO-LABS project, under Grant Agreement No 101057511
References:
[1] E. Majorana, Soryushiron Kenkyu Electronics 63, 149 (1981).
[2] E. Majorana, Il Nuovo Cimento (1924-1942) 14, 171 (1937).
[3] C.M. Ho and R.J. Scherrer, Physics Letters B 722, 341 (2013).
[4] C. Giunti and C.W. Kim. Oxford University Press Book, (2007).
[5] J. Dawson, D. Degering, M. Köhler, R. Ramaswamy, C. Reeve, J.R. Wilson, and K. Zuber, Physical Review C 78, 035503 (2008).
[6] M.J. Hwang et al., Astroparticle Physics 31, 412 (2009).
[7] V. Nanal, EPJ Web of Conferences 66, 08005 (2014).
[8] P. Grabmayr, The European Physical Journal A 60, 115 (2024).
[9] E.L. Fireman, Physical Review 75, 323 (1949).
[10] V. Singh, G. Yashwant, S. Mathimalar, N. Dokania, V. Nanal, R.G. Pillay, V.M. Datar, AIP Conf. Proc. 1405, 334 (2011).
[11] N. Dokania, V. Singh, S. Mathimalar, C. Ghosh, V. Nanal, R.G. Pillay, S. Pal, K.G. Bhushan and A. Shrivastava, Journal of Instrumentation 9, P11002 (2014).
[12] EXFOR Database, https://www-nds.iaea.org/exfor/
[13] C. Rubbia et al., CERN-LHC-98-002-EET-Add. 1. (1998).
[14] V. Alcayne et al., Radiation Physics and Chemistry 217, 111525 (2024).
[15] J. Balibrea-Correa et al., Nuclear Instruments and Methods in Physics Research Section A 1072, 170110 (2025).