ANOMALOUS THERMAL NEUTRON CAPTURE AND SUB-SURFACE Pd-ISOTOPES SEPARATION IN COLD- WORKED PALLLADIUM FOILS AS A RESULT OF DEUTERIUM LOADING

The process of thermal neutron absorption in the coldworked Pd cathodes during electrolysis in NaOD/D2O solution under irradiation by Ultraweak Thermalized Neutron Field (UTNF) was studied. It was found that during deuterium loading the probability of thermal neutron absorption in a strained Pd is increased by a factor 8 compared to the unstrained (annealed) sample or sample where loading is not carried out. Symmetric separation of Pd isotope pairs of Pd-Pd and Pd-Pd occurring in the subsurface layer down to 500 A depth in the cold worked Pd foil loaded with deuterium is observed. It is established that observed Pd isotope separation is solely defined by a strong plastic deformation (mechanical strain), induced by deuterium loading in Pd-matrix. The effect of Pd-isotopes separation is strongly enhanced under UTNF irradiation 1, INTRODUCTION If the phenomenon of Cold Fusion or Lattice Induced Nuclear Reactions (LINR) is really exist then the effects of nuclear interaction in crystalline lattice of metal deuterides should be sharply distinct of that in vacuum/plasma environment. Earlier it was shown that DD-reaction rate and branching ratios at low deuteron energies are strongly affected by crystalline lattice of some metals, including Pd [1,2]. However, the study of low energy deuteron interaction with Pd-metal is limited by the deuteron energy (Ed >2.5 keV) due to presence of nuclear Coulomb barrier, leading to dramatic decrease in the nuclear reaction yields at lower projectile energy. To rule out the Coulomb barrier influence on the nuclear interactions in solids we suggested to irradiate deuterated metal targets by the neutral particles, i.e. neutrons and study change in neutron capture cross-section in these targets [3]. As we showed in our previous works, the thermalized neutron capture cross-section in metals during electrolysis can be enhanced drastically due to specific inelastic scattering processes [4,5]. The phenomenon of increase in thermal neutron cross-sections is accompanied by a strong plastic deformation of irradiated non-equilibrium solids and leads to appearance of new unexpected properties in them. In order to observe structural changes and anomalous neutron capture the solid and UTNF should be satisfied following conditions [3-5]:  High Excitation of the solid, which produces non-equilibrium optic phonon mode of energy E  ħD. Broad (“white”) neutron spectra (0.1-10 kT) overlaps the optic vibration frequency (D) of excited system.  Use an isotropic neutron field (not a beam) to allow neutron (with momentum p) interactions with various directions of lattice phonon Debye wave vector kD. In present paper we studied the process of thermal neutron absorption and accompanying macro and micro-plastic deformation effects in the cold-worked Pd cathodes during electrolysis in NaOD/D2O solution under irradiation by Ultraweak Thermalized Neutron Field (UTNF). 2, EXPERIMENTAL TECHNIQUE In the present work we are strictly concerned with UTNF, defined by a highly rarefied neutron gas (a low neutron density n≤ 10 cm or a low flux Φn≤ 2*10 n/s*cm) with under-Maxwellian velocities (with mean energy ~ 1 10 kT) and isotropic angular distribution. In order to create the neutrons field with flux Φn ~200 n/s*cm the set up consisting of cavity with the Cf neutron source and the test sample surrounded with a large mass (~ 1 metric ton) of moderator (PE) is being used (Fig.1). The intensity of neutron source inside the cavity was 2x10n/s in 4 π solid angle. The mean neutron energy in the cavity in accordance to Monte-Carlo simulation was found ≈ 80 meV. The monitoring of neutron flux intensity inside the cavity was carried out by direct detection of thermal neutron (BF3 neutron counters) and by measurement (with HpGe detector) of the 2225 keV gamma-line intensity from neutron capture in moderator according to the: n + H → D + γ (2225 keV). The electrolytic cell was placed inside the Pb-shielded cavity near the HpGe detector.