New insights in muon-catalyzed dd fusion by using ortho-para controlled solid deuterium

For the first time, we observed the dependence of the ddmu formation rate and the dmu hyperfine-transition rate on the ortho-para state in muon-catalyzed fusion in the solid D2 state, and found that the effect is even opposite to a recent theoretical prediction. We also determined the back-decay rate and the hyperfine-transition rate via scattering in solid state by using the ortho-para dependence. A theory to describe properly our experimental result is called for to understand the nature of muon-catalyzed fusion in the solid state.     

Calculation of muon fraction stopped in the dt-cell of a 14 MeV neutron generator

The muon utilization efficiency is calculated for a model of a neutron source based on muon-catalyzed fusion, and the intensity and neutron flux are estimated in this system.     

Measuring sticking and stripping in muon-catalyzed dt fusion with multilayer thin films

We propose a direct measurement of muon sticking to alpha particles in muon-catalyzed dt fusion at a high density. Exploiting the features of a multilayer thin-film target developed at TRIUMF, the sticking is determined directly by detection of charged fusion products. Experimental separation of initial sticking and stripping may become possible for the first time. Monte Carlo simulations, as well as preliminary results of test measurements are described.     

Three-body integral equations and their application to the reactions of muon transfer

Hyperfine Interactions - It is suggested to use the integral Faddeev equations in the Alt-Grassberger-Sandhas form to calculate the muon transfer reactions relevant to muon-catalyzed fusion....     

Tritium handling

Hyperfine Interactions - In recent years there has been much research into muon-catalyzed fusion in gas mixtures including tritium. To perform such research it is necessary to construct a...     

Calculation of sticking using theR-matrix method with the Bloch operator

We calculate the effects of nuclear forces on the sticking in muon-catalyzed d-t fusion using theR-matrix method. The importance of the Bloch operator in this calculation is emphasized. We try to clarify some features in the formulation that seem to have caused confusion in the past. Some speculations are made regarding the remaining discrepancy of the calculated sticking with experimental values.     

Collisional problems in the μCF cycle before muonic molecule formation

Important processes in the muon-catalyzed fusion cycle preceding muonic molecule formation are discussed. These include muonic atom formation as well as the subsequent elastic, isotopic-exchange, and hyperfine-state quenching collisions of the muonic atoms. Modern methods for atomic capture of the negative muon are reviewed. Elastic and inelastic cross sections obtained in the improved adiabatic representation are given, and rates at liquidhydrogen density are tabulated for easy reference and comparison.     

Experimental investigation of muon-catalyzed dt fusion in wide ranges of D/T mixture conditions

A vast program of the experimental investigation of muon-catalyzed dt fusion was performed on the Joint Institute for Nuclear Research phasotron. Parameters of the dt cycle were obtained in a wide range of the D/T mixture conditions: temperatures of 20–800 K, densities of 0.2–1.2 of the liquid hydrogen density (LHD), and tritium concentrations of 15–86%. In this paper, the results obtained are summarized.     

Raman spectrographic system for quantitative analysis of isotopic hydrogen mixtures for muon catalysis experiments

We show that Raman spectral lines from H₂, D₂, T₂, HD, HT and DT are readily resolved, permitting an effective means to analyze isotopic hydrogen mixtures used in muon-catalyzed fusion experiments. We propose a Raman spectrographic system to allow for real-time analysis of targets involving all three isotopes of hydrogen.     

Intense thermal neutron source based on MCF

The conceptual scheme of an ecologically clean thermal neutron source (TNS) based on muon-catalyzed fusion (MCF) is proposed. The preliminary design shows that an MCF-based TNS can produce the maximum value of unperturbed thermal neutron flux 10¹⁵ n/cm² s using for muon production a beam power of about 14 MW supplied by an accelerator of the next generation.     

Muon-catalyzed fusion theory

Some topics in muon-catalyzed fusion theory are discussed: Resonant formation ofddμ molecules appears to be well understood, with good agreement so far between theory and experiment. The situation for resonantdtμ formation is much less clear, because of the more complicated kinetics, the apparent three-body effect, and the evident need to treat thermalization and molecular formation together to compare theory and experiment. Recent theoretical progress inpdμ fusion by Friar et al. has resolved a serious discrepancy in the Wolfenstein-Gershtein effect, i.e., the increase inpdμ fusion yield with increased deuterium fraction.     

Time-of-flight measurement of resonant molecular formation in muon-catalyzed dt fusion

Preliminary results are reported for an experiment at TRIUMF where a time-of-flight technique was tested for measuring the energy dependence of the rate for muon-catalyzed dt fusion. Muonic tritium atoms were created following transfer of negative muons from muonic protium in a layer of solid hydrogen (protium) containing a small fraction of tritium. The atoms escaped from the solid layer via the Ramsauer-Townsend mechanism, traversed a drift region of 18 mm, and then struck an adjacent layer of deuterium, where the muonic atom could form a molecular system. The time of detection of a fusion product (neutron or alpha) following muon arrival is dependent upon the energy of the muonic tritium atom as it traverses the drift region. By comparison of the time distribution of fusion events with a prediction based on the theoretical energy dependence of the rate, the strength of resonant formation can in principle be determined. The results extracted so far are discussed and the limitations of the method are examined.     

Experimental results on muon-catalyzed dt fusion

A comprehensive experimental study of the kinetics of muon-catalyzed dt fusion has been conducted at PSI, based on the measurement of the 14 MeV neutrons from the fusion process. The target conditions included densities from 1–150% of the atomic density of liquid hydrogen, relative tritium concentrations of 2–95%, and temperatures of 13–300 K. Information about the dt cycle has been obtained from the measured neutron time distributions by different methods: Monte Carlo simulations primarily aimed at investigating epithermal effects in molecular formation and the determination and interpretation of cycling rates describing the steady state regime.     

Measurement of the resonant d(mu)t molecular formation rate in solid HD

Measurements of muon-catalyzed dt fusion ( d(mu)t-->4He + n + mu(-)) in solid HD have been performed. The theory describing the energy dependent resonant molecular formation rate for the reaction (mu)t + HD-->[(d(mu)t)pee](*) is compared to experimental results in a pure solid HD target. Constraints on the rates are inferred through the use of a Monte Carlo model developed specifically for the experiment. From the time-of-flight analysis of fusion events in 16 and 37 microg x cm(-2) targets, an average formation rate consistent with 0.897+/-(0.046)(stat)+/-(0.166)(syst) times the theoretical prediction was obtained.     

Coulomb final state interaction in identical Boson interferometry

Recently, the muonic three-body systemdtμ, has aroused considerable attention in relation to the realization of a useful muon-catalyzed fusion [1, 2]. This bound system must be solved up to 6 digits in energy to establish the muon catalyzed fusion process. We applied the ATMS method [3] and the coupled-channel method [4] to the Coulomb three-body system and obtained the detailed information on the energy levels and the wave functions of the bound states. Further we investigated the effect of the nuclear interaction on the fusion rate in the bound states [5] and developed a formalism to calculate the muon sticking to⁴He [6]. In this paper we report the results obtained in our collaborations: Figure 2 shows up our main results.     

The kinetics of muon-catalyzed dt fusion

A main source of information about the muon-catalyzed fusion cycle in D-T mixtures are the cycling rates _c, which are characteristic for the kinetic equilibrium of states attained rapidly in dense targets. The measurement, analysis and interpretation of these rates will be discussed, concentrating on the extensive set of rates observed at PSI over the last decade in gaseous, liquid and solid targets.Invited talk presented by Peter Kammel.     

Screening corrections in cold deuterium fusion rates

We have recalculated the fusion rates of the free deuterium molecule, ion and mesomolecule taking into account the shielding of the Coulomb barrier by the electrons and muon. Electron screening increases the rates by several orders of magnitude. The fusion of hydrogen nuclei is known to be the source of energy of stars occuring in their high-temperature, high-pressure interiors. In terrestrial conditions, one attempts currently to tap this source of nuclear fusion energy by alternative techniques, i.e. high-temperature plasmas or muon-catalyzed fusion. Very recently cold fusion in solids has achieved worldwide attention, since experimental evidence for increased hydrogenic fusion rates in palladium and titanium has been reported[1,2]. These reports have motivated us to reconsider the fusion probability of free hydrogen molecules, ions and mesomolecules, following closely the studies of Refs. [3,4,5]. Our aim however is to improve the previous estimates of the respective fusion rates by taking account of the screening effects of the electrons and muons on the nuclear Coulomb barrier which will turn out to be quite important. As in Ref. [5] we will restrict our numerical results to deuterium only.     

New approach to the old problem of muon sticking in µCF

A new approach is presented for evaluation of the muon sticking probability to helium in muon-catalyzed fusion reactions. Use of the sudden approximation is avoided. The probability _s of muon sticking to helium in the reaction dtµ µ⁴He+n, calculated with the new method, agrees with previous results. Moreover, the energy and angular distributions for the emitted muon, as well as the dependence of w_s on the energy radiated during the muon-catalyzed fusion event, have been evaluated.     

μCF Intense Neutron Source and Nuclear Waste Incineration

It was shown in a series of papers, that a 14-MeV intense neutron source based on muon-catalyzed fusion with intensity J = 10¹⁷ n/s and flux Φ = 10¹⁴ n/s/cm² can be constructed on the current technology base. Also it was demonstrated that 14 MeV neutrons are essential to drive effective transmutation of problematic radionuclides. For this reason, advanced methods of the neutron generation are outlined in the present paper with the focus on the beam parameter estimations inherent in the KEK-JAERI project. This revised version was published online in August 2006 with corrections to the Cover Date.