학술논문
Study of multi-neutron emission in the $\beta$-decay of $^{11}$Li
Document Type
Working Paper
Author
Delaunay, F.; Achouri, N. L.; Algora, A.; Assié, M.; Balibrea, J.; Banerjee, K.; Bhattacharya, C.; Borge, M. J. G.; Cano-Ott, D.; Fernández-Domínguez, B.; Fraile, L. M.; Gibelin, J.; Lund, M. V.; Madurga, M.; Marqués, F. M.; Marroquin, I.; Martínez, T.; Mendoza, E.; Orr, N. A.; Pârlog, M.; Pereira-López, X.; Pestel, V.; Riisager, K.; Santos, C.; Sénoville, M.; Tengblad, O.; Vedia, V.
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Subject
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Abstract
The kinematics of two-neutron emission following the $\beta$-decay of $^{11}$Li was investigated for the first time by detecting the two neutrons in coincidence and by measuring their angle and energy. An array of liquid-scintillator neutron detectors was used to reject cosmic-ray and $\gamma$-ray backgrounds by pulse-shape discrimination. Cross-talk events in which two detectors are fired by a single neutron were rejected using a filter tested on the $\beta$-1n emitter $^9$Li. A large cross-talk rejection rate is obtained ($> 95 \%$) over most of the energy range of interest. Application to $^{11}$Li data leads to a significant number of events interpreted as $\beta$-2n decay. A discrete neutron line at $\approx$ 2 MeV indicates sequential two-neutron emission, possibly from the unbound state at 10.6 MeV excitation energy in $^{11}$Be.
Comment: 4 pages, Proceedings of the EuNPC2018 Conference
Comment: 4 pages, Proceedings of the EuNPC2018 Conference