Bubble fusion is the non-technical name for a nuclear fusion reaction hypothesized to occur inside extraordinarily large collapsing gas bubbles created in a liquid during acoustic cavitation . The more technical name is sonofusion .
80-472: AICF may refer to: Acoustic Inertial Confinement Fusion, official term for bubble fusion All India Carrom Federation All India Chess Federation America Israel Cultural Foundation American Indian College Fund Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title AICF . If an internal link led you here, you may wish to change
160-434: A health threat to humans. It is estimated that a 70 kg (154 lb) person might drink 4.8 litres (1.3 US gal) of heavy water without serious consequences. Small doses of heavy water (a few grams in humans, containing an amount of deuterium comparable to that normally present in the body) are routinely used as harmless metabolic tracers in humans and animals. The deuteron has spin +1 (" triplet state ") and
240-764: A natural abundance in Earth's oceans of about one atom of deuterium in every 6,420 atoms of hydrogen. Thus, deuterium accounts for about 0.0156% by number (0.0312% by mass) of all hydrogen in the ocean: 4.85 × 10 tonnes of deuterium – mainly as HOD (or HO H or H HO) and only rarely as D 2 O (or H 2 O) (Deuterium Oxide, also known as Heavy Water )– in 1.4 × 10 tonnes of water. The abundance of H changes slightly from one kind of natural water to another (see Vienna Standard Mean Ocean Water ). The name deuterium comes from Greek deuteros , meaning "second". American chemist Harold Urey discovered deuterium in 1931. Urey and others produced samples of heavy water in which
320-437: A colleague's name on one of his papers who had not actually been involved in the research ("the sole apparent motivation for the addition of Mr. Bugg was a desire to overcome a reviewer's criticism", the report concluded). Taleyarkhan's appeal of the report's conclusions was rejected. He said the two allegations of misconduct were trivial administrative issues and had nothing to do with the discovery of bubble nuclear fusion or
400-415: A committee with members from five institutions had investigated 12 allegations of research misconduct against Rusi Taleyarkhan. It concluded that two allegations were founded—that Taleyarkhan had claimed independent confirmation of his work when in reality the apparent confirmations were done by Taleyarkhan's former students and was not as "independent" as Taleyarkhan implied, and that Taleyarkhan had included
480-473: A deuterium nucleus (actually a highly excited state of it), a nucleus with two protons, and a nucleus with two neutrons. These states are not stable. The deuteron wavefunction must be antisymmetric if the isospin representation is used (since a proton and a neutron are not identical particles, the wavefunction need not be antisymmetric in general). Apart from their isospin, the two nucleons also have spin and spatial distributions of their wavefunction. The latter
560-547: A higher boiling point (23.64 vs. 20.27 K), a higher critical temperature (38.3 vs. 32.94 K) and a higher critical pressure (1.6496 vs. 1.2858 MPa). The physical properties of deuterium compounds can exhibit significant kinetic isotope effects and other physical and chemical property differences from the protium analogs. H 2 O, for example, is more viscous than normal H 2 O . There are differences in bond energy and length for compounds of heavy hydrogen isotopes compared to protium, which are larger than
640-414: A neutron and an "up" state (↑) being a proton. A pair of nucleons can either be in an antisymmetric state of isospin called singlet , or in a symmetric state called triplet . In terms of the "down" state and "up" state, the singlet is This is a nucleus with one proton and one neutron, i.e. a deuterium nucleus. The triplet is and thus consists of three types of nuclei, which are supposed to be symmetric:
720-414: A process that uses hydrogen sulfide gas at high pressure. While India is self-sufficient in heavy water for its own use, India also exports reactor-grade heavy water. Formula: D 2 or 1 H 2 Data at about 18 K for H 2 ( triple point ): Compared to hydrogen in its natural composition on Earth, pure deuterium ( H 2 ) has a higher melting point (18.72 K vs. 13.99 K),
800-598: A ratio of as much as 23 atoms of deuterium per million hydrogen atoms in undisturbed gas clouds, which is only 15% below the WMAP estimated primordial ratio of about 27 atoms per million from the Big Bang. This has been interpreted to mean that less deuterium has been destroyed in star formation in the Milky Way galaxy than expected, or perhaps deuterium has been replenished by a large in-fall of primordial hydrogen from outside
880-480: A report by Rusi Taleyarkhan and collaborators that claimed to have observed evidence of sonofusion. The claim was quickly surrounded by controversy, including allegations ranging from experimental error to academic fraud. Subsequent publications claiming independent verification of sonofusion were also highly controversial. Eventually, an investigation by Purdue University found that Taleyarkhan had engaged in falsification of independent verification, and had included
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#1732802463052960-452: A student as an author on a paper when he had not participated in the research. He was subsequently stripped of his professorship. One of his funders, the Office of Naval Research reviewed the report by Purdue and barred him from federal funding for 28 months. US patent 4,333,796, filed by Hugh Flynn in 1978, appears to be the earliest documented reference to a sonofusion-type reaction. In
1040-551: A thorough investigation"; in response, Purdue announced that it would re-open its investigation. In June 2008, a multi-institutional team including Taleyarkhan published a paper in Nuclear Engineering and Design to "clear up misconceptions generated by a webposting of UCLA which served as the basis for the Nature article of March 2006", according to a press release. On July 18, 2008, Purdue University announced that
1120-542: Is about 10.6% denser than normal water (so that ice made from it sinks in normal water). Heavy water is slightly toxic in eukaryotic animals, with 25% substitution of the body water causing cell division problems and sterility, and 50% substitution causing death by cytotoxic syndrome (bone marrow failure and gastrointestinal lining failure). Prokaryotic organisms, however, can survive and grow in pure heavy water, though they develop slowly. Despite this toxicity, consumption of heavy water under normal circumstances does not pose
1200-422: Is about three times that of Earth water. This has caused renewed interest in suggestions that Earth's water may be partly of asteroidal origin. Deuterium has also been observed to be concentrated over the mean solar abundance in other terrestrial planets, in particular Mars and Venus. Deuterium is produced for industrial, scientific and military purposes, by starting with ordinary water—a small fraction of which
1280-417: Is about three times that of Earth water. This figure is the highest yet measured in a comet. H HR's thus continue to be an active topic of research in both astronomy and climatology. Deuterium is often represented by the chemical symbol D. Since it is an isotope of hydrogen with mass number 2, it is also represented by H. IUPAC allows both D and H, though H is preferred. A distinct chemical symbol
1360-624: Is another one of the arguments in favor of the Big Bang over the Steady State theory of the Universe. The observed ratios of hydrogen to helium to deuterium in the universe are difficult to explain except with a Big Bang model. It is estimated that the abundances of deuterium have not evolved significantly since their production about 13.8 billion years ago. Measurements of Milky Way galactic deuterium from ultraviolet spectral analysis show
1440-413: Is antisymmetric under nucleons exchange due to isospin, and therefore must be symmetric under the double exchange of their spin and location. Therefore, it can be in either of the following two different states: In the first case the deuteron is a spin triplet, so that its total spin s is 1. It also has an even parity and therefore even orbital angular momentum l . The lower its orbital angular momentum,
1520-418: Is barely bound at E B = 2.23 MeV , and none of the higher energy states are bound. The singlet deuteron is a virtual state, with a negative binding energy of ~60 keV . There is no such stable particle, but this virtual particle transiently exists during neutron–proton inelastic scattering, accounting for the unusually large neutron scattering cross-section of the proton. The deuterium nucleus
1600-453: Is called a deuteron . It has a mass of 2.013 553 212 544 (15) Da (just over 1.875 GeV/ c ). The charge radius of a deuteron is 2.127 78 (27) × 10 m . Like the proton radius , measurements using muonic deuterium produce a smaller result: 2.125 62 (78) fm . Deuterium is one of only five stable nuclides with an odd number of protons and an odd number of neutrons. ( H, Li , B , N , Ta ;
1680-402: Is in the s = 1 , l = 0 state. The same considerations lead to the possible states of an isospin triplet having s = 0 , l = even or s = 1 , l = odd . Thus, the state of lowest energy has s = 1 , l = 1 , higher than that of the isospin singlet. The analysis just given is in fact only approximate, both because isospin is not an exact symmetry, and more importantly because
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#17328024630521760-477: Is naturally occurring heavy water —and then separating out the heavy water by the Girdler sulfide process , distillation, or other methods. In theory, deuterium for heavy water could be created in a nuclear reactor, but separation from ordinary water is the cheapest bulk production process. The world's leading supplier of deuterium was Atomic Energy of Canada Limited until 1997, when the last heavy water plant
1840-439: Is symmetric if the deuteron is symmetric under parity (i.e. has an "even" or "positive" parity), and antisymmetric if the deuteron is antisymmetric under parity (i.e. has an "odd" or "negative" parity). The parity is fully determined by the total orbital angular momentum of the two nucleons: if it is even then the parity is even (positive), and if it is odd then the parity is odd (negative). The deuteron, being an isospin singlet,
1920-460: Is the ratio found in the gas giant planets, such as Jupiter. The analysis of deuterium–protium ratios ( H HR) in comets found results very similar to the mean ratio in Earth's oceans (156 atoms of deuterium per 10 hydrogen atoms). This reinforces theories that much of Earth's ocean water is of cometary origin. The H HR of comet 67P/Churyumov–Gerasimenko , as measured by the Rosetta space probe,
2000-429: Is thought to have played an important role in setting the number and ratios of the elements that were formed in the Big Bang . Combining thermodynamics and the changes brought about by cosmic expansion, one can calculate the fraction of protons and neutrons based on the temperature at the point that the universe cooled enough to allow formation of nuclei . This calculation indicates seven protons for every neutron at
2080-434: Is thought to represent close to the primordial Solar System ratio. This is about 17% of the terrestrial ratio of 156 deuterium atoms per million hydrogen atoms. Comets such as Comet Hale-Bopp and Halley's Comet have been measured to contain more deuterium (about 200 atoms per million hydrogens), ratios which are enriched with respect to the presumed protosolar nebula ratio, probably due to heating, and which are similar to
2160-490: Is thus a boson . The NMR frequency of deuterium is significantly different from normal hydrogen. Infrared spectroscopy also easily differentiates many deuterated compounds, due to the large difference in IR absorption frequency seen in the vibration of a chemical bond containing deuterium, versus light hydrogen. The two stable isotopes of hydrogen can also be distinguished by using mass spectrometry . The triplet deuteron nucleon
2240-493: Is used for convenience because of the isotope's common use in various scientific processes. Also, its large mass difference with protium ( H) confers non-negligible chemical differences with H compounds. Deuterium has a mass of 2.014 102 Da , about twice the mean hydrogen atomic weight of 1.007 947 Da , or twice protium's mass of 1.007 825 Da . The isotope weight ratios within other elements are largely insignificant in this regard. In quantum mechanics ,
2320-465: Is warranted". Their report also stated that "vigorous, open debate of the scientific merits of this new technology is the most appropriate focus going forward." In order to verify that the investigation was properly conducted, House Representative Brad Miller requested full copies of its documents and reports by March 30, 2007. His congressional report concluded that "Purdue deviated from its own procedures in investigating this case and did not conduct
2400-498: The H had been highly concentrated. The discovery of deuterium won Urey a Nobel Prize in 1934. Deuterium is destroyed in the interiors of stars faster than it is produced. Other natural processes are thought to produce only an insignificant amount of deuterium. Nearly all deuterium found in nature was produced in the Big Bang 13.8 billion years ago, as the basic or primordial ratio of H to H (≈26 atoms of deuterium per 10 hydrogen atoms) has its origin from that time. This
2480-471: The Solar System (as confirmed by planetary probes), and in the spectra of stars , is also an important datum in cosmology . Gamma radiation from ordinary nuclear fusion dissociates deuterium into protons and neutrons, and there is no known natural process other than Big Bang nucleosynthesis that might have produced deuterium at anything close to its observed natural abundance. Deuterium is produced by
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2560-417: The electromagnetic interaction relative to the strong nuclear interaction . The symmetry relating the proton and neutron is known as isospin and denoted I (or sometimes T ). Isospin is an SU(2) symmetry, like ordinary spin , so is completely analogous to it. The proton and neutron, each of which have iso spin-1/2 , form an isospin doublet (analogous to a spin doublet ), with a "down" state (↓) being
2640-427: The quantum state of the deuterium is a superposition (a linear combination) of the s = 1 , l = 0 state and the s = 1 , l = 2 state, even though the first component is much bigger. Since the total angular momentum j is also a good quantum number (it is a constant in time), both components must have the same j , and therefore j = 1 . This is the total spin of the deuterium nucleus. To summarize,
2720-427: The reduced mass of the deuterium is markedly higher than that of protium. In nuclear magnetic resonance spectroscopy , deuterium has a very different NMR frequency (e.g. 61 MHz when protium is at 400 MHz) and is much less sensitive. Deuterated solvents are usually used in protium NMR to prevent the solvent from overlapping with the signal, though deuterium NMR on its own right is also possible. Deuterium
2800-550: The sonoluminescence pulse, a key indicator that its source was fusion caused by the heat and pressure inside the collapsing bubbles. The results were so startling that the Oak Ridge National Laboratory asked two independent researchers, D. Shapira and M. J. Saltmarsh, to repeat the experiment using more sophisticated neutron detection equipment. They reported that the neutron release was consistent with random coincidence. A rebuttal by Taleyarkhan and
2880-524: The strong nuclear interaction between the two nucleons is related to angular momentum in spin–orbit interaction that mixes different s and l states. That is, s and l are not constant in time (they do not commute with the Hamiltonian ), and over time a state such as s = 1 , l = 0 may become a state of s = 1 , l = 2 . Parity is still constant in time, so these do not mix with odd l states (such as s = 0 , l = 1 ). Therefore,
2960-545: The March 8, 2002 issue of the peer-reviewed journal Science , Rusi P. Taleyarkhan and colleagues at the Oak Ridge National Laboratory (ORNL) reported that acoustic cavitation experiments conducted with deuterated acetone ( C 3 D 6 O ) showed measurements of tritium and neutron output consistent with the occurrence of fusion. The neutron emission was also reported to be coincident with
3040-501: The School of Nuclear Engineering at Purdue, and several of his colleagues at Purdue, had convinced Taleyarkhan to move to Purdue and attempt a joint replication. In the 2006 Nature report they detail several troubling issues when trying to collaborate with Taleyarkhan. He reported positive results from certain set of raw data, but his colleagues had also examined that set and it only contained negative results. He never showed his colleagues
3120-500: The US Patent Office. The examiner called the experiment a variation of discredited cold fusion , found that there was "no reputable evidence of record to support any allegations or claims that the invention is capable of operating as indicated", and found that there was not enough detail for others to replicate the invention. The field of fusion suffered from many flawed claims, thus the examiner asked for additional proof that
3200-436: The Universe became cool enough to form deuterium (at about a temperature equivalent to 100 keV ). At this point, there was a sudden burst of element formation (first deuterium, which immediately fused into helium). However, very soon thereafter, at twenty minutes after the Big Bang, the Universe became too cool for any further nuclear fusion or nucleosynthesis. At this point, the elemental abundances were nearly fixed, with
3280-543: The Vice President for Research. In a March 9, 2006 article entitled "Evidence for bubble fusion called into question", Nature interviewed several of Taleyarkhan's colleagues who suspected something was amiss. On February 7, 2007, the Purdue University administration determined that "the evidence does not support the allegations of research misconduct and that no further investigation of the allegations
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3360-668: The background. When the same experiment was performed with non-deuterated control liquid, the measurements were within one standard deviation of background, indicating that the neutron production had only occurred during cavitation of the deuterated liquid. William M. Bugg, emeritus physics professor at the University of Tennessee also traveled to Taleyarkhan's lab to repeat the experiment with his equipment. He also reported neutron emission, using plastic neutron detectors. Taleyarkhan claimed these visits counted as independent replications by experts, but Forringer later recognized that he
3440-440: The beginning of nucleogenesis , a ratio that would remain stable even after nucleogenesis was over. This fraction was in favor of protons initially, primarily because the lower mass of the proton favored their production. As the Universe expanded, it cooled. Free neutrons and protons are less stable than helium nuclei, and the protons and neutrons had a strong energetic reason to form helium-4 . However, forming helium-4 requires
3520-406: The co-authors were working in his laboratory under his supervision, and his peers in the faculty were not allowed to review the data. In summary, Taleyarkhan's colleagues at Purdue said he placed obstacles to peer review of his experiments, and they had serious doubts about the validity of the research. Nature also revealed that the process of anonymous peer-review had not been followed, and that
3600-418: The deuterium nucleus is antisymmetric in terms of isospin, and has spin 1 and even (+1) parity. The relative angular momentum of its nucleons l is not well defined, and the deuteron is a superposition of mostly l = 0 with some l = 2 . In order to find theoretically the deuterium magnetic dipole moment μ , one uses the formula for a nuclear magnetic moment with g and g are g -factors of
3680-675: The energy levels of electrons in atoms depend on the reduced mass of the system of electron and nucleus. For a hydrogen atom , the role of reduced mass is most simply seen in the Bohr model of the atom, where the reduced mass appears in a simple calculation of the Rydberg constant and Rydberg equation, but the reduced mass also appears in the Schrödinger equation , and the Dirac equation for calculating atomic energy levels. The reduced mass of
3760-406: The energy was "reasonably close" to that which was expected from a fusion reaction. In February 2005 the documentary series Horizon commissioned two leading sonoluminescence researchers, Seth Putterman and Kenneth S. Suslick , to reproduce Taleyarkhan's work. Using similar acoustic parameters, deuterated acetone, similar bubble nucleation, and a much more sophisticated neutron detection device,
3840-697: The galaxy. In space a few hundred light years from the Sun, deuterium abundance is only 15 atoms per million, but this value is presumably influenced by differential adsorption of deuterium onto carbon dust grains in interstellar space. The abundance of deuterium in Jupiter 's atmosphere has been directly measured by the Galileo space probe as 26 atoms per million hydrogen atoms. ISO-SWS observations find 22 atoms per million hydrogen atoms in Jupiter. and this abundance
3920-416: The initial bubble collapse following bubble nucleation, whereas this report claimed neutron emission many acoustic cycles later. In July 2005, two of Taleyarkhan's students at Purdue University published evidence confirming the previous result. They used the same acoustic chamber, the same deuterated acetone fluid and a similar bubble nucleation system. In this report, no neutron-sonoluminescence coincidence
4000-453: The intermediate step of forming deuterium. Through much of the few minutes after the Big Bang during which nucleosynthesis could have occurred, the temperature was high enough that the mean energy per particle was greater than the binding energy of weakly bound deuterium; therefore, any deuterium that was formed was immediately destroyed. This situation is known as the deuterium bottleneck . The bottleneck delayed formation of any helium-4 until
4080-418: The isotopic differences in any other element. Bonds involving deuterium and tritium are somewhat stronger than the corresponding bonds in protium, and these differences are enough to cause significant changes in biological reactions. Pharmaceutical firms are interested in the fact that H is harder to remove from carbon than H. Deuterium can replace H in water molecules to form heavy water ( H 2 O), which
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#17328024630524160-538: The journal Nuclear Engineering and Design was not independent from the authors. Taleyarkhan was co-editor of the journal, and the paper was only peer-reviewed by his co-editor, with Taleyarkhan's knowledge. In 2002 Taleyarkhan filed a patent application on behalf of the United States Department of Energy, while working in Oak Ridge. Nature reported that the patent had been rejected in 2005 by
4240-407: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=AICF&oldid=1002930266 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Bubble fusion The term was coined in 2002 with the release of
4320-419: The long-lived radionuclides K , V , La , Lu also occur naturally.) Most odd–odd nuclei are unstable to beta decay , because the decay products are even–even , and thus more strongly bound, due to nuclear pairing effects . Deuterium, however, benefits from having its proton and neutron coupled to a spin-1 state, which gives a stronger nuclear attraction; the corresponding spin-1 state does not exist in
4400-404: The lower its energy. Therefore, the lowest possible energy state has s = 1 , l = 0 . In the second case the deuteron is a spin singlet, so that its total spin s is 0. It also has an odd parity and therefore odd orbital angular momentum l . Therefore, the lowest possible energy state has s = 0 , l = 1 . Since s = 1 gives a stronger nuclear attraction, the deuterium ground state
4480-553: The midst of accusations concerning Taleyarkhan's research standards, two different scientists visited the meta-stable fluids research lab at Purdue University to measure neutrons, using Taleyarkhan's equipment. Dr. Edward R. Forringer and undergraduates David Robbins and Jonathan Martin of LeTourneau University presented two papers at the American Nuclear Society Winter Meeting that reported replication of neutron emission. Their experimental setup
4560-586: The nuclear force. In both cases, this causes the diproton and dineutron to be unstable . The proton and neutron in deuterium can be dissociated through neutral current interactions with neutrinos . The cross section for this interaction is comparatively large, and deuterium was successfully used as a neutrino target in the Sudbury Neutrino Observatory experiment. Diatomic deuterium ( H 2 ) has ortho and para nuclear spin isomers like diatomic hydrogen, but with differences in
4640-407: The number and population of spin states and rotational levels , which occur because the deuteron is a boson with nuclear spin equal to one. Due to the similarity in mass and nuclear properties between the proton and neutron, they are sometimes considered as two symmetric types of the same object, a nucleon . While only the proton has electric charge, this is often negligible due to the weakness of
4720-458: The only change as some of the radioactive products of Big Bang nucleosynthesis (such as tritium ) decay. The deuterium bottleneck in the formation of helium, together with the lack of stable ways for helium to combine with hydrogen or with itself (no stable nucleus has a mass number of 5 or 8) meant that an insignificant amount of carbon, or any elements heavier than carbon, formed in the Big Bang. These elements thus required formation in stars. At
4800-473: The other authors of the original report argued that the Shapira and Saltmarsh report failed to account for significant differences in experimental setup, including over an inch of shielding between the neutron detector and the sonoluminescing acetone. According to Taleyarkhan et al. , when properly considering those differences, the results were consistent with fusion. As early as 2002, while experimental work
4880-467: The outer solar atmosphere at roughly the same concentration as in Jupiter, and this has probably been unchanged since the origin of the Solar System. The natural abundance of H seems to be a very similar fraction of hydrogen, wherever hydrogen is found, unless there are obvious processes at work that concentrate it. The existence of deuterium at a low but constant primordial fraction in all hydrogen
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#17328024630524960-509: The paper just to overcome the criticism of one reviewer, and that this was part of an attempt of "an effort to falsify the scientific record by assertion of independent confirmation". The investigation did not address the validity of the experimental results. In January 2006, a paper published in the journal Physical Review Letters by Taleyarkhan in collaboration with researchers from Rensselaer Polytechnic Institute reported statistically significant evidence of fusion. In November 2006, in
5040-539: The radiation was generated from fusion and not from other sources. An appeal was not filed because the Department of Energy had dropped the claim in December 2005. Doubts among Purdue University's Nuclear Engineering faculty as to whether the positive results reported from sonofusion experiments conducted there were truthful prompted the university to initiate a review of the research, conducted by Purdue's Office of
5120-404: The rare cluster decay , and occasional absorption of naturally occurring neutrons by light hydrogen, but these are trivial sources. There is thought to be little deuterium in the interior of the Sun and other stars, as at these temperatures the nuclear fusion reactions that consume deuterium happen much faster than the proton–proton reaction that creates deuterium. However, deuterium persists in
5200-498: The ratio of these two numbers, which is 1.000272. The wavelengths of all deuterium spectroscopic lines are shorter than the corresponding lines of light hydrogen, by 0.0272%. In astronomical observation, this corresponds to a blue Doppler shift of 0.0272% of the speed of light , or 81.6 km/s. The differences are much more pronounced in vibrational spectroscopy such as infrared spectroscopy and Raman spectroscopy , and in rotational spectra such as microwave spectroscopy because
5280-475: The ratios found in Earth seawater. The recent measurement of deuterium amounts of 161 atoms per million hydrogen in Comet 103P/Hartley (a former Kuiper belt object), a ratio almost exactly that in Earth's oceans (155.76 ± 0.1, but in fact from 153 to 156 ppm), emphasizes the theory that Earth's surface water may be largely from comets. Most recently the H HR of 67P/Churyumov–Gerasimenko as measured by Rosetta
5360-486: The raw data corresponding to the positive results, despite several requests. He moved the equipment from a shared laboratory to his own laboratory, thus impeding review by his colleagues, and he didn't give any advance warning or explanation for the move. Taleyarkhan convinced his colleagues that they shouldn't publish a paper with their negative results. Taleyarkhan then insisted that the university's press release present his experiment as "peer-reviewed" and "independent", when
5440-505: The researchers could find no evidence of a fusion reaction. In 2004, new reports of bubble fusion were published by the Taleyarkhan group, claiming that the results of previous experiments had been replicated under more stringent experimental conditions. These results differed from the original results in that fusion was claimed to occur over longer times than previously reported. The original report only claimed neutron emission from
5520-619: The same time, the failure of much nucleogenesis during the Big Bang ensured that there would be plenty of hydrogen in the later universe available to form long-lived stars, such as the Sun. Deuterium occurs in trace amounts naturally as deuterium gas ( H 2 or D 2 ), but most deuterium atoms in the Universe are bonded with H to form a gas called hydrogen deuteride (HD or H H). Similarly, natural water contains deuterated molecules, almost all as semiheavy water HDO with only one deuterium. The existence of deuterium on Earth, elsewhere in
5600-669: The scientific community. On August 27, 2008, he was stripped of his named Arden Bement Jr. Professorship, and forbidden to be a thesis advisor for graduate students for at least the next 3 years. Despite the findings against him, Taleyarkhan received a $ 185,000 grant from the National Science Foundation between September 2008 and August 2009 to investigate bubble fusion. In 2009 the Office of Naval Research debarred him for 28 months, until September 2011, from receiving U.S. Federal Funding. During that period his name
5680-408: The system in these equations is close to the mass of a single electron, but differs from it by a small amount about equal to the ratio of mass of the electron to the nucleus. For H, this amount is about 1837 / 1836 , or 1.000545, and for H it is even smaller: 3671 / 3670 , or 1.0002725. The energies of electronic spectra lines for H and H therefore differ by
5760-454: The two-neutron or two-proton system, due to the Pauli exclusion principle which would require one or the other identical particle with the same spin to have some other different quantum number, such as orbital angular momentum . But orbital angular momentum of either particle gives a lower binding energy for the system, mainly due to increasing distance of the particles in the steep gradient of
5840-509: The underlying science, and that "all allegations of fraud and fabrication have been dismissed as invalid and without merit — thereby supporting the underlying science and experimental data as being on solid ground". A researcher questioned by the LA Times said that the report had not clarified whether bubble fusion was real or not, but that the low quality of the papers and the doubts cast by the report had destroyed Taleyarkhan's credibility with
5920-468: Was attempted. An article in Nature raised issues about the validity of the research and complaints from his Purdue colleagues (see full analysis elsewhere in this page). Charges of misconduct were raised, and Purdue University opened an investigation. It concluded in 2008 that Taleyarkhan's name should have appeared in the author list because of his deep involvement in many steps of the research, that he added one author that had not really participated in
6000-446: Was listed in the 'Excluded Parties List' to prevent him from receiving further grants from any government agency. Deuterium Deuterium ( hydrogen-2 , symbol H or D , also known as heavy hydrogen ) is one of two stable isotopes of hydrogen ; the other is protium, or hydrogen-1, H. The deuterium nucleus ( deuteron ) contains one proton and one neutron , whereas the far more common H has no neutrons. Deuterium has
6080-469: Was not an expert, and Bugg later said that Taleyarkhan performed the experiments and he had only watched. In March 2006, Nature published a special report that called into question the validity of the results of the Purdue experiments. The report quotes Brian Naranjo of the University of California, Los Angeles to the effect that neutron energy spectrum reported in the 2006 paper by Taleyarkhan, et al.
6160-557: Was shut down. Canada uses heavy water as a neutron moderator for the operation of the CANDU reactor design. Another major producer of heavy water is India. All but one of India's atomic energy plants are pressurized heavy water plants, which use natural (i.e., not enriched) uranium. India has eight heavy water plants, of which seven are in operation. Six plants, of which five are in operation, are based on D–H exchange in ammonia gas. The other two plants extract deuterium from natural water in
6240-457: Was similar to previous experiments in that it used a mixture of deuterated acetone, deuterated benzene , tetrachloroethylene and uranyl nitrate . Notably, however, it operated without an external neutron source and used two types of neutron detectors . They claimed a liquid scintillation detector measured neutron levels at 8 standard deviations above the background level, while plastic detectors measured levels at 3.8 standard deviations above
6320-505: Was statistically inconsistent with neutrons produced by the proposed fusion reaction and instead highly consistent with neutrons produced by the radioactive decay of Californium 252 , an isotope commonly used as a laboratory neutron source . The response of Taleyarkhan et al. , published in Physical Review Letters , attempts to refute Naranjo's hypothesis as to the cause of the neutrons detected. Tsoukalas, head of
6400-420: Was still in progress, Aaron Galonsky of Michigan State University, in a letter to the journal Science expressed doubts about the claim made by the Taleyarkhan team. In Galonsky's opinion, the observed neutrons were too high in energy to be from a deuterium -deuterium (d-d) fusion reaction. In their response (published on the same page), the Taleyarkhan team provided detailed counter-arguments and concluded that
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