Resonantddμformation in condensed deuterium

Abstract

The rate of ddµ muonic molecule resonant formation in dµ atom collision with a condensed deuterium target is expressed in terms of a single-particle response function. In particular, ddµ formation in solid deuterium at low pressures is considered. Numerical calculations of the rate in the case of fcc polycrystalline deuterium at 3 K have been performed using the isotropic Debye model of solid. It is shown that the energy-dependent ddµ formation rates in the solid differ strongly from those obtained for D 2 gaseous targets, even at high dµ kinetic energies. Monte Carlo neutron spectra from dd fusion in ddµ molecules have been obtained for solid targets with different concentrations of ortho-and para-deuterium. The recent experimental results performed in low pressure solid targets (statistical mixture of ortho-D 2 and para-D 2 ) are explained by the presence of strong recoilless resonance peaks in the vicinity of 2 meV and very slow deceleration of dµ atoms below 10 meV. A good agreement between the calculated and experimental spectra is achieved when a broadening of D 2 rovibrational levels in solid deuterium is taken into account. It has been shown that resonant ddµ formation with simultaneous phonon creation in solid gives only about 10% contribution to the fusion neutron yield. The neutron time spectra calculated for pure ortho-D 2 and para-D 2 targets are very similar. A practically constant value of the mean ddµ formation rate, observed for different experimental conditions, is ascribed to the fact that all the recent measurements have been performed at temperatures T 19 K, much lower than the target Debye temperature Θ D ≈ 110 K. In result, the formation rate, obtained in the limit T /Θ D ≪ 1, depends weakly on the temperature.

New Insights in Muon-CatalyzedddFusion by using Ortho-Para Controlled Solid Deuterium

“…Our result did not show the lack of strong resonant formation from F 3=2 in the ortho deuterium case predicted by Gurin and Menshikov [14,15] effects, rotational deexcitation, and other effects [22]. As written in their paper [22], our previous data [16,17] supported their calculation, which predicts a somewhat lower fusion yield for targets with a more ortho deuterium molecule. However, in the present experiment, we confirmed that there was certainly an ortho-para dependence of the resonant formation rate and the d hyperfine-transition rate.…”

“…However, a theoretical prediction in the solid state is not available even in the recent theory by Adamczak et al [22]. It is interesting whether each of 3=2 1=2 back d and 3=2 1=2 scat d is properly reproduced by the theory or not.…”

“…The experimental value of the fast in ortho deuterium was confirmed to be smaller than that in normal deuterium with good accuracy. However, Adamczak's value of fast is larger than that in normal deuterium [22], and a more detailed theory that includes the proper solid-state effect is necessary. Now we discuss our experimental result of the hyperfine-transition rate.…”

Preparation of ortho-para ratio controlled D2 gas for muon-catalyzed fusion

“…Such observations are crucial for several unsolved problems related to the condensed-matter effect in CF, e.g., unexpectedly high rates of resonant dd formation observed in several studies. [7][8][9] Resonant muonic molecular formation mechanism in pure D 2 was first explained by Vesman. 4 Because of the shallow bound state ͑⑀ 11 ϳ −1.96 eV͒ in the dd molecule with the rotational/vibrational state ͑J , ͒ = ͑1,1͒, a dd molecule is formed resonantly from a d atom:…”

Density effect in d - d catalyzed fusion with ortho-and para-enriched deuterium

“…We have successfully observed a clear difference in d-d fusion neutron spectra between ortho-, normal-and paraenriched D 2 . Recently, in order to determine the nature of the condensed-matter effect, we observed the ortho-para dependent phenomena in different target densities at similar temperatures with low-density gas, φ ≤ 0.17 LHD (liquid hydrogen density: 4.25×10 22 atoms/cc) and T = 36.2 K, and pressurized liquid, φ ≥ 0.86 LHD and T ≥ 35 K. Such an experiment is not only a sensitive examination of the ortho-para effect predicted by the existing μCF theories [2] (Faifman, private communication), but also essential to understand a high-density effect in condensed matter [7,8].…”