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Muon-Catalyzed Fusion in Deuterium and Tritium

#3487


Investigation of the Fusion Reactions in Muonic Molecules of Deuterium and Tritium

Tech Area / Field

  • MAT-ALL/High Performance Metals and Alloys/Materials
  • PHY-SSP/Solid State Physics/Physics

Status
3 Approved without Funding

Registration date
16.03.2006

Leading Institute
Joint Institute of Nuclear Research, Russia, Moscow reg., Dubna

Supporting institutes

  • VNIIEF, Russia, N. Novgorod reg., Sarov\nResearch Coordination Center on the Problem of Muon Catalyzed Fusion and Exotic Quantum Systems, Russia, Moscow

Collaborators

  • TU Delft, The Netherlands, Delft\nInstitute of Nuclear Physics (IFJ), Poland, Krakov\nUniversity of British Columbia / TRIUMF, Canada, BC, Vancouver\nInstitute of Physical and Chemical Research (RIKEN) / Nishina Center for Accelerator-Based Science Advanced Meson Science Laboratory, Japan, Saitama, Wako

Project summary

Muon-catalyzed fusion (MCF) is a wide unique and independent direction of the modern physics. MCF includes study of the mu-atomic and mu-molecular processes and nuclear reactions in bound states of the muonic molecules and is relevant to different adjacent fields (nuclear physics, physics of weak interactions, astrophysics, solid state physics, study of the properties of the lightest nuclei, including different exotic nuclear systems, precision spectroscopy of exotic atoms etc.).

Problem to solve by means of the Project consists in the study of the MCF properties in different mixtures of the hydrogen isotopes, knowing of which is necessary both for the modern fundamental physics and for the development of the novel technologies which will provide the safe production of energy and the utilization of the radioactive waste with the use of MCF. The aim of the Project is the obtaining of new experimental data in the region where MCF was poorly studied or was not studied at all and where it represents the most interest for the modern theory and for the future practical application. First of all it is the determination of the MCF d+t reaction parameters at high temperatures, where theory predicts the high intensity of the process. It is also the study of the MCF d+d reaction at lowest temperatures, where the exotic mechanisms of the muonic molecule formation caused by phonon effects in solid and liquid deuterium come into action. And at last, it is the study of the mechanism of the t+t reaction catalyzed by muon, enabling the possibility to obtain the unique information about the structure of nuclei with A=6.

State of affairs in the scope of the Project and significance of the proposed investigations

  1. MCF in pure tritium. Because of a number of reasons (first of all radiation safety and difficulty of the isotope-pure tritium receipt) the MCF process in tritium is studied comparatively poorly (the accuracy in the determination of its main parameters is only 30 %). Unique systems of the detection of MCF reaction products created by us allows in considerable extent to get over the experimental difficulties and reach the accuracy better than 10 %, that is one of the tasks of the Project. Presence of powerful theoretical support will allow to conduct the analysis of the neutron energy spectrum with consideration of the concrete mechanisms of t+t reaction from p-wave at ultra-low energy, and this will allow to obtain the valuable information for the physics of light nuclei.
  2. MCF in pure deuterium. Formation of the ddµ molecules in gaseous deuterium is excellently described by the “standard” resonant Vesman theory. The really impressive achievement is the precise agreement between experiment and theory in the temperature dependence of the ddµ molecule formation rate in gaseous deuterium. This allowed to determine the binding energy of the loosely bound state of ddµ molecule with a very high accuracy. At the same time, results of the measurements for liquid and solid deuterium (T<30 K) are in sharp contradiction with the «standard» theory. Mechanisms suggested to explain the experimental data include a set of exotic effects. It is important, that contributions of these effects are sensitive to the molecular structure of deuterium. So, for the reason to check the modern theory, we propose to conduct measurements with normal (statistical mixture of the ortho- and para-molecules) and pure ortho-state of deuterium at different temperatures and density and at different aggregative states.
  3. MCF in the D/T and H/D/T mixtures. Investigation of the MCF process of d+t reaction in D/T and H/D/T mixtures represents the special importance, because it is characterized by high intensity (more then 100 reactions induced by a muon). Since the corresponding resonances of muonic molecule formation are located in the tµ-atom energy region ~ 0.1 eV, the largest effect must be reached at high mixture temperature (1000-2000 K). At present this process is well studied only at low temperature. Systematic investigations in the high-temperature region T = (300-800) K were conducted only in JINR. The task of the Project is carrying out the measurements using the unique high-temperature target with the aim to determine the intensity of the dtµ-molecule formation resonances and the highest yield of neutrons from d+t reaction. As well as, according to theory, the maximum intensity of resonances takes place in the case of dtµ-molecule formation in process tµ+HD, the especially important task is to obtain results for high-temperature H/D/T mixture.

Expected results and their application
  1. Experimental data on the basic parameters of MCF cycle in pure tritium (ttµ-molecule formation rate, rate of nuclear t+t reaction and probability of muon-to-helium sticking in this reaction) with an accuracy (7-10) %. Obtaining the information about mechanism of nuclear t+t reaction and about influence of correlation of particles in final state.
  2. Precise (5-7 %) experimental data on the ddµ-molecule formation rate in normal mixture of ortho and para states and in pure ortho-state of deuterium molecules in the temperature range T=6-35 K, covering solid, liquid and gaseous state of deuterium. It will allow to check the modern theory and determine the role of different exotic mechanisms, influencing on the MCF process at low temperature.
  3. Experimental data on the parameters of MCF cycle in D/T/ and H/D/T mixtures in unexplored range of high temperature (900-1600) K. It will allow checking the theoretical calculations for the location and intensity of the dtµ-molecule formation resonances.

Besides the scientific significance, all mentioned experimental results will have enormous practical importance for the development of the installations on the base of MCF (as well as choice of their work conditions), intending for the producing of 14 MeV-neutrons and utilization of the long-living radioactive waste.

The Project participant competency in the considered area

JINR. The group made a prominent contribution to the MCF experimental study. The Dubna group discovered the phenomenon of the ddµ-molecule resonance formation and later directly confirmed its existence by measurements of the temperature dependence of the ddµ-molecule formation rate. This group firstly experimentally investigated the MCF reaction d+t and confirmed the theoretical predictions of the high intensity of this process, which induced the activity in the MCF study throughout the world. Since 1995 at the JINR Phasotron our collaboration has carried out a large program of investigation of MCF processes in solid, liquid and gaseous D2, D/T and H/D/T in wide ranges of temperature and density. Results of these investigations were broadly published, including in international journals, and presented in numerous international conferences and workshops.

FSUE RFNC-VNIIEF. Collective concerns with investigation in field of weapon technologies and has a great experience of work on the interaction of hydrogen isotopes, especially tritium, with materials and also on the design and producing of the unique targets for the MCF process study. Here the unique installation for preparation and conducting experiments on the MCF in hydrogen isotopes was constructed. Results of these investigations and designs were patented, broadly published, including in international journals, and presented in numerous international conferences and workshops.

RCC MUCATEX. Participants of the Project are leading theorists in the field of MCF. The discovery (theoretical prediction) of the resonant dtµ-molecule formation induced the activity in the MCF study throughout the world. Results of the numerous theoretical works are recognized all over the world, published in leading world journals and presented in numerous international conferences and workshops.

Meeting ISTC Goals and Objectives: The Project is intended on the obtaining of new important experimental data on MCF, knowing which is necessary both for the fundamental physics and for the further applying in the design of new installations, which will provide safer and more favorable for environment production of nuclear energy and utilization of the long-living radioactive waste. It is proposed that this goal will be achieved with the aid of as already existing unique methods of preparing, conducting and analyzing of MCF experiments as on the base of new technologies of target design and production, which will be elaborated during realization of the Project. For decision of this task it is intended to use the experience and potential of the leading Russian institute on the nuclear weapon (FSUE RFNC-VNIIEF).

Scope of Activities: In the scope of the project it is proposed the elaboration, production and testing of three targets, preparation and conducting of three experiments and analysis of the results of these experiments.

Role of Foreign Collaborators: Foreign collaborators will take an active part in the Project on the stage of analysis of gathered experimental data and theoretical foundation of results obtained. It is assumed that collaborators from Delft University of Technology will take part in the calculations of neutron detection efficiency for all proposed experiments and also in analysis of neutron energy spectrum taking into account concrete mechanisms of t+t reactions, taking place from p-wave at ultra-low energies. It is assumed that collaborator from Institute of Nuclear Physics will take part in the theoretical foundation of the experiment with low-temperature deuterium. It is planed to conduct mutual consultations and discussions of results with collaborator from TRIUMF on all proposed experiments.

Technical Approach and Methodology: Experimental investigations of MCF processes in pure tritium, deuterium and in D/T and H/D/T mixtures are proposed. Specially designed targets will be exposed on the muon beam of DLNP JINR Phasotron. Targets will be filled with hydrogen isotopes with the use of special radioactive-safe gas handling system. Muons, stopped in hydrogen isotope mixture, catalyzed the formation of muonic molecules and nuclear reactions in them. Special detection system, based on two full-absorption neutron detectors, will detect fusion neutrons and µ-decay electrons. Time chains of signals from detectors will be registered by flashes analog-to-digital converter.


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