Some surprising results of experiments using ultrasound induced transient cavitation on metal targets in a heavy water system are reported. The evidence leads to the unavoidable conclusion that controlled nuclear fusion reactions have been achieved. These reactions are identified by the selective production of 3He and 4He via cavitation induced solid state nuclear processes at near room temperature. The method has been in development at since discovery experiments in 1989. Recent experiments were performed by the authors while in residence as Visiting Scientists at Los Alamos National Laboratories (LANL) during Oct. 1993 and again in April 1994.

Melted Palladium Target from
Sonofusion Experiment
50mm x 50mm x 0.1mm

The aim of the experiments was to demonstrate the ready reproducibility of the heat and helium producing methods in a Mark II research device. Measurement of 3He and 4He was performed at the Rocketdyne Division of Rockwell International (Canoga Park, CA). supported by funding from the Exploratory Research Division of the Electric Power Research Institute (EPRI, Palo Alto). The experiments at Los Alamos were monitored for neutron emissions with a 3He neutron detector, liquid nitrogen cooled germanium gamma detectors, and liquid scintillation detectors for tritium. None of the methods revealed signals above background. This monitoring was performed under the direction of LANL scientists.

The experiments involved target metals of palladium and titanium (50mm x 50mm x 0.1-0.2mm) in a small reaction vessel filled with heavy water (D2O). The reactor vessel is operated with an argon atmosphere. In operation the target is bombarded by 20 khz ultrasound resulting in transient cavitation in the heavy water filled reactor. The heavy water circulates through the vacuum tight stainless steel reactor and external heat exchanger. Samples representing a large fraction of reaction gases were taken using stainless steel sample cylinders at the end of a few hours of operation.

Mass spectroscopy of gas samples was performed by Dr. Brian Oliver of Rockwell Rocketdyne to measure evolved 3He and 4He atoms and relative concentrations in both gas and small target metal samples. The pressurizing gas, which is high purity argon, had a 4He level of <0.475 appm ±0.008 appm. Measurement of the atmospheric concentration of 4He performed at Rockwell has shown a level of 5.22 appm. In one sample of reaction chamber gas taken after a short experiment levels of 4He were found to be 2.550 appm ±0.01 appm. In a second sample of gas taken following a longer ~20 hour experiment the level of 4He was found to be 552 appm ±1.0 appm (>e18 atoms corrected to the total volume of the apparatus).

Levels of 3He were determined to be below the sensitivity limit of the instrument of about 2 x e10 atoms in the pressurizing gas. In the short experiment reactor gas the levels of 3He were determined to be 0.3appb (4 x e11 atoms). The ratio of 4He and 3He in this sample proved to be on the order of ~182, far from the expected ratio of 8 x e5. 4He levels observed in these experiments were in good agreement with measurements from a large number of similar experiments as determined at the U.S. Bureau of Mines Helium Field Laboratory (Amarillo, TX) and at SRI International (Menlo Park, CA.). Additional analysis of gas samples for 22Ne:4He ratio has revealed 22Ne is missing from the gas. 22Ne would be expected if the 4He were from any normal source of helium.

We are often asked if the helium measured could come from a source of contamination. The fact that the isotopic ratio of the measured helium is found to be dramatically shifted from the expected normal abundance ratio, contamination during handling or via inclusions helium is effectively ruled out. Over the course of the helium studies, blank experiments have not revealed elevated levels of helium from the samples of gas or target metal.

Helium in the metal is essentially non-mobile. To release it for measurement requires heating the metal to vaporize it. A small amount of helium was detected in narrow range in both virgin metal and metal taken following experiments. Helium present in the target metal is 4-5 orders of magnitude too low to account for the helium observed in the reactor gas. In the case of the palladium target metal the helium measured ranged from 0.2-8.3 x e9 atoms in samples ranging from 6.03 - 10.92 mg ± 0.02mg in mass.

Total mass of the palladium targets is approximately 3 grams which suggests the maximum total helium in the target could be 2.2 x e12 atoms. In the case of the titanium targets the helium measured in the target metal ranges from 0.6-83.8 x e9 atoms in 7.6-8.0mg of metal which would provide 1.1 x e13 atoms. The heavy water is degassed before use ruling it out as a source of helium in the system.

The authors' experimental apparatus and method is a complex one which cannot be adequately described in this short presentation. It involves the use of acoustically induced transient cavitation resulting in an adiabatic collapse of bubbles on the metal targets within a reaction vessel. This adiabatic collapse heats the contents of the bubble, heavy water vapor, to temperatures exceeding 5000° C. The energy within the collapsing bubble due to adiabatic collapse is added to by the effects of a shock wave that is produced as the bubble collapse reaches the speed of sound It is reported by many researchers that energies in the bubble in excess of 10,000° C are produced through the combined effect of the adiabatic and shock wave systems. Pressure in an bubble may be as high as 200 Mbar and a density (in H2O) up to 13.4 g/cm2.

It is quite clear that, at a minimum, the energy in the collapsing bubble exceeds that necessary to dissociate chemical bonds and it is likely high enough to strip electrons from the atoms present. Under properly controlled conditions this collapse results in energetic acceleration and direction of the bubble contents via a jet onto the adjacent metal lattice. The interaction of the jet leads to 2 types of lattice damage: classical cavitation erosion and internal heating ejecta (described later in this report).

We surmise that high densities of hydrogen isotopes in the metal lattice are created and impinged upon by the multitudinous bubble events which cycle 20,000 times per second. Observation of hundreds of experiments shows that these conditions typically result in steady state heat production with a greater heat output from the system than can be accounted for by energy input to the system. The energy input to the reactor system is less than 5 watts/ cm2. The energy produced by the reaction in the neighborhood of the target exceeds an energy density of megajoules per gram (1/35th mole) of target material. The largest known chemical transformation in palladium is to the bromide at 0.9MJ/mole. The experiments are highly reproducible and produce large heat excesses, 10 to 100+ watts net excess of heat energy measured using steady state calorimetric methods.

Steady state calorimetry based on Newton's Law of Cooling (convection cooling) is used to determine the heat production and includes a carefully planned multi-stage calibration sequence. In all calibration steps the system is maintained as close to identical conditions as possible. The first step in calibrating the system is to add a calibrated resistance heater in place of the ultrasound energy source and raise the apparatus to a steady state temperature near that of an active experiment and then allow it to cool back to under static conditions.

A personal computer data acquisition system is used to collect readings from up to 14 thermocouples attached at various points to the apparatus. Operating pressures and flow rates are maintained as closely as possible to replicate to active operating conditions. The calibration allows calculation of constants for the rate cooling for each element in the system. The second calibration step is to run experiments in the system with ordinary water as the operating fluid, with the ultrasound as the energy input source, and with an active target. The system is operated in the same mode as with heavy water and similar data to the previous calibration run is collected. This provides a means to compare the ordinary water and ultrasound with the resistance heating source and secondly to an active run with heavy water and a similar or sometimes the identical target. Finally the third step is to run experiments with the ultrasound where a non-active target material is used in heavy water, again operating the system under identical conditions as in an active run.

Under these calorimetry methods which employ algorithms the observation of net excess heat production and helium production is observed in the case of palladium or titanium targets in heavy water. Similar excess heat is not observed in the ordinary water system. Helium production as a reaction indices is within an order of magnitude matching excess energy.

Further studies are underway by the authors in collaboration with scientists at several national laboratories to attempt to identify the precise location of the reactions in the system and the presumed nuclear reactions yielding the observed helium. Classical hot fusion reactions have been ruled out given the absence of measured neutrons or gamma emissions from the system. At this point the authors do not propose a precise mechanism for the reaction(s).

One group of interesting candidate reactions are found amongst various D-alpha reactions with other nuclei which might conceivably yield the observed helium in the absence of neutrons or gamma. If such D-alpha reactions involving other nuclei were being produced within the system no evidence save the observed helium would escape the heavily constructed stainless steel reaction chamber. Another possible reaction might be a unique D+D reaction where the 23.8 MeV release could be distributed within the lattice in less than 10-20 s. The energy of the presumed alpha particles which are observed as 4He in the authors experiments is not yet established.

We wish to acknowledge the assistance and support of Dr. Dale Tuggle and Dr. Thomas Claytor of Los Alamos National Laboratory where key experiments in this paper were performed, Dr. Thomas Passell of the Electric Power Research Institute in Palo Alto who provided the funds for the analysis at Rockwell/Rocketdyne, and Dr. Brian Oliver of Rocketdyne whose state of the art mass spectroscopy lab and fine scientific methods provided outstanding analytical results. To the many other scientists at Los Alamos National Labs, SRI International, the Naval Research Laboratory, Lockheed, Stanford University, Portland State University, Battelle Pacific NW Labs, and elsewhere who have contributed their time and equipment to help build a body of evidence, thanks.

E-mail to the author    rgeorge@d2fusion.com

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