Possible observation of the dineutron in the ¹⁵⁹ Tb (n, ² n) ^158g Tb nuclear reaction

Abstract

Experimental observation of the 159 Tb(n, 2 n) reaction product was performed with application of the activation technique. Tb specimen of natural composition was irradiated with (d, d) neutrons of 5.39 and 7 MeV energies. Instrumental spectra of Tb specimen were measured with HPGe spectrometer. An unexpected 944.2 keV γ-ray peak was observed. Other γ-ray lines due to 158g Tb decay were identified as well. A bonded dineutron emission with the binding energy (B dn ) within limitations 1.3 MeV < B dn < 2.8 MeV is evidenced by the energy of incident neutrons and by the 158g Tb presence in the output channel. The specific nuclear properties of 158 Tb as deformed nucleus were discussed to explain a bonded dineutron formation based on theoretical assumptions and calculations, using standard parameters for this mass region.

Statistically significant observation of and cross-sections for a new nuclear reaction channel on 197Au with bound dineutron escape

“…Thus, statistically significant observation of a bound dineutron in the 197 Au(n, 2 n) 196 Au nuclear reaction, and in addition the true conclusion about a manifestation of dineutron escape in the 159 Tb(n, 2 n) 158 Tb nuclear reaction in [3], both demonstrated that Migdal's prediction about the possible formation and existence of a bound dineutron in the outgoing channel of nuclear reaction is experimentally confirmed. Then thorough study of the energy dependence of the cross-section with application of VdG accelerators, operating in a neutron generation mode and aiming at precise identification of the maximum positions in discrete spectrum and corresponding cross-section value could enable us to deeply understand between which levels in compound nucleus and beyond of residual nucleus but within its potential well this dineutron formation takes place.…”

“…By definition, for such nuclei the two-neutrons separation energy (S 2n ) must be less than 1 MeV, but for 198 Au S 2n equals 14.585 MeV, so it is certainly not the case. In [3] we provided the very first evidence of a bound dineutron appearing as the two-neutron nucleus in the outgoing channel of the 159 Tb (n, 2 n) 158 Tb nuclear reaction based on the prediction by Migdal in [2]. Our experimental results and some estimates in [3] were done for a configuration of the dineutron located in close proximity to 158 Tb -the nucleus of prolate shape with deformation parameter β Tb = 0.31 [6].…”

New Direction in Nuclear Physics Originated from the Neutron Activation Technique Application

“…One year after the last 6.85 MeV neutron irradiation, the same Tb sample was placed on HPGe detector for about two weeks instrumental spectrum acquisition. In this spectrum, among the background and some still remaining 160 Tb decay gammas, a peak was detected with 944.2 keV gamma energy [9]. A thorough analysis of possible interfering reactions, contaminants and Tb sample impurities allowed to unambiguously conclude about the presence in the output channel of 6.85 MeV neutron induced reaction on 159 Tb of 158g Tb isotope (T 1/2 = 180 years) as a product of 159 Tb(n, x) 158g Tb nuclear reaction.…”

“…Moreover, an application of this technique gave us a chance to observe a dineutron emission in the 159 Tb(n, 2 0 n) 158g Tb nuclear reaction according to Migdal's prediction [11]. 70 years after the theoretical foundation of the dineutron in [1], the evidence for a dineutron existence as a bonded particle was provided in [9]. This event opens up the new direction in Nuclear Physics: physics of the dineutron, or dineutron physics.…”

“…Then the energy aspects of a dineutron emission in nuclear reaction would be similar to emission of the deuteron below the threshold of the corresponding nuclear reaction with the neutron and proton in the output channel. The interval estimates for the binding energy and half-life value for the dineutron are obtained and presented in [9]. From our measurement, it was also possible to derive a point estimate for the 159 Tb(n, 2 0 n) 158(m+g) Tb nuclear reaction cross section for 6.85 MeV neutron energy only.…”