Resonant Molecular-Nuclear Fusion
Resonant Molecular-Nuclear Fusion, Relevant Aspects of Single Bubble Sonoluminescence, and New-Type Picosecond-Pulse Light Sources
Tech Area / Field
- PHY-ANU/Atomic and Nuclear Physics/Physics
8 Project completed
Senior Project Manager
Pradas-Poveda J I
Joint Institute of Nuclear Research, Russia, Moscow reg., Dubna
- Russian Academy of Sciences / Institute of Nuclear Research, Russia, Moscow\nNIIIT (Pulse Techniques), Russia, Moscow\nInstitute of Physical-Technical Problems, Russia, Moscow reg., Dubna\nSt Petersburg State University / Institute of Physics, Russia, St Petersburg
- Goettingen University, Germany, Göttingen\nUniversity of Illinois, USA, IL, Urbana\nUniversity of Washington, USA, WA, Seattle
Project summaryThe present project includes some problems associated with new hypothesized power sources (nuclear reactions within the molecules of chemical compounds, fusion and quantum vacuum radiation in sonoluminescence), and an applied-physics problem: development of simple and inexpensive sources of subnananosecond light pulses based on SBSL.
1. Intra-molecular nuclear fusion
This part of the project is directed at theoretical study and experimental observation of a new nuclear-physics phenomenon, that is the molecular-nuclear transitions.
Theoretical review. It is known that nuclear states with the energy by the nuclear scale of values next to a threshold of break down of the nuclei have enlarged spatial dimensions. For example, the ground states of the nucleus 8B is separated from the threshold of two-particle break-down channel by 130 keV, and this makes necessary to take into account the interaction up to 300 fm between the proton and Be-nucleus, i.e., at much larger distances than the standard range of nuclear forces.
In some cases the presence of near threshold resonances leads to a considerable enhancement of the rate of transition to such states relatively to the transition to the bound states of the nuclei.
Experimental methods and approaches. It is supposed to perform some high-precision and low-background measurements of products in the exit channel by means of nuclear-spectroscopy methods. Details of the inpidual methods will be determined by the search for the optimum conditions, under which the investigated process are allowed by the quantum-mechanical rules, providing at the same time the higher sensitivity of the measurements in general. The measurements will be performed at the underground laboratory of the Baksan Neutrino Observatory at the Caucasus located underneath a rock layer of about 5,000 m of the water equivalent.
It is suggested to study some external factors, which could increase the yield of molecular-nuclear transitions.
First of all, experiments with water are stipulated. Next, some other compounds will be studied: HF, NH, and LiH enriched with 6Li and D. Concurrently the theory will be in progress directed at a quantitative model for calculating the weights of the admixture of nuclear states in the total wave functions of molecular systems. Thus, the exact values of the transition rates in various polyatomic systems will be obtained.
2. Study of Sonoluminescence (SL)
A term sonoluminescence (SL) is referred to a radiation of light (VIS and UV) by gas bubbles in liquids under the influence of strong ultrasound. Fundamental interest to the SL appeared only recently, after the discovery of single-bubble sonoluminescence (SBSL), in which a single, stable, acoustically levitated gas bubble can be made to pulsate with a sufficiently large amplitude to emit light each acoustic cycle. It appears that exciting physics may be associated with this phenomenon. At a moment of maximum compression of the bubble, hot plasma is expected to arise. Herewith a temperature sufficient for thermonuclear reactions is not excluded to occur in a case of appropriate composition of the gas mixture inside the bubble. Other hypotheses link the light emission observed (at least some part of it) with the energy of zero-point quantum fluctuations of the physical vacuum.
Thus, study of the SL is important in connection with problems of stability of plasma micro-targets used in the laser fusion, as well as for the Quantum Electrodynamics (QED) in connection with the dynamical Casimir effect. Unique properties of light emission in SBSL also make it prospective for some applications. A new type of ultrashort light-pulse sources of a sub-nanosecond or even picosecond range can be developed. Due to a simplicity and low cost anticipated, it may find widespread applications in science and technology.
Experiments on Sonoluminescence. Studies of sonoluminescence are directed to testing the existing suggestions on the physical nature of this effect.
Search for the thermonuclear effects. For that aim, a strong short pulse excitation synchronized with SL light flash, with the amplitude of about several bars, is necessary to be combined with the driving ultrasound activation of the SL-resonator. If the system contains deuterium dissolved in heavy water D2O, then a neutron yield of about ~0.1 nph can be anticipated. Measurements of this lowest neutron rate will be performed by means of a triple-coincidence method using a special neutron counter with a so-called active moderator (fast liquid organic scintillator) with an array of 3He proportional neutron counters plunged into it. The triple-coincidence events are to be selected in accordance to a criteria as follows:
(SL light-flash) +(Scintillation in neutron moderator)+(Signal from 3He-counter).
The measurements will be performed at the underground laboratory of the Baksan Neutrino Observatory, as in the molecular-fusion experiments. Under background conditions of this laboratory the estimated sensitivity is 0.01 nph for about a three-month measuring cycle.
Some other experiments are considered also.
- Dissociation model of SL. Direct measurement of secondary products of nitrogen dissociation, that of various nitrogen oxides NOx and products of their subsequent chemical interaction with water. The long-term runs of SBSL will be performed for accumulation of their measurable amount in the volume of a sealed SL resonator.
- Search for the indications of co-operative mechanism in SL. One of the co-operative mechanisms in SL responsible for the large ensemble of atoms “to flash out in unison” may be the quantum entanglement of the atoms at a moment of maximum compression of the bubble. The non-local quantum correlations of the pair photons in SL will be carried out, and thus the evidence is expected for the famous Einstein-Podolsky-Rosen effect in SL light source.
- Correlation study of the successive light flashes in SL.
- Probing temperature inside the SL bubble. Absorptive processes in the surrounding fluid (usually water) limit current measurements of the SL spectrum. Thus, energies above 6 eV have not been observed. A method will again consist of shifting the spectrum into the softer region, and estimating the actual temperature within the bubble by reconstructing the initial spectrum in the region beyond the water absorption. An alternative approach will be a measurement of IR part of the spectrum in a case of xenon-doped bubbles. Xenon emission at high pressure shows distinctive IR lines. Thus, temperature may be estimated by the Doppler widths of these lines.
3. Development of a new type of super fast pulse light sources
The present data on SL are far off sufficiency for formulating an adequate physical model. However, they already allow motivating practical applications of this process in light sources operating on the SBSL-principle.
This project stipulates a development of sources of ultrashort light pulses of sub-nanosecond (possibly, picosecond) range. Such sources are anticipated to be tens or even up to a hundred times less expensive as compared to laser sources with similar temporal performances. Hence, they may find various scientific and technological applications. In the physics, chemistry and biology–for studying some high-speed light-induced processes. In instruments production–for testing and time-calibration of high-speed photomultipliers, microchannel plates, and other fast photo-transducers.
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