Inertial confinement fusion
Inertial confinement fusion is a type of fusion energy research that attempts to initiate nuclear fusion reactions by heating and compressing a fuel target in the form of a pellet that most contains a mixture of deuterium and tritium. Typical fuel pellets contain around 10 milligrams of fuel. To compress and heat the fuel, energy is delivered to the outer layer of the target using high-energy beams of laser light, electrons or ions, although for a variety of reasons all ICF devices as of 2015 have used lasers; the heated outer layer explodes outward, producing a reaction force against the remainder of the target, accelerating it inwards, compressing the target. This process is designed to create shock waves. A sufficiently powerful set of shock waves can compress and heat the fuel at the center so much that fusion reactions occur. ICF is one of two major branches of fusion energy research, the other being magnetic confinement fusion; when it was first proposed in the early 1970s, ICF appeared to be a practical approach to power production and the field flourished.
Experiments during the 1970s and'80s demonstrated that the efficiency of these devices was much lower than expected, reaching ignition would not be easy. Throughout the 1980s and'90s, many experiments were conducted in order to understand the complex interaction of high-intensity laser light and plasma; these led to the design of newer machines, much larger, that would reach ignition energies. The largest operational ICF experiment is the National Ignition Facility in the US, designed using the decades-long experience of earlier experiments. Like those earlier experiments, however, NIF has failed to reach ignition and is, as of 2015, generating about 1⁄3 of the required energy levels. Fusion reactions combine lighter atoms, such as hydrogen, together to form larger ones; the reactions take place at such high temperatures that the atoms have been ionized, their electrons stripped off by the heat. Nuclei are positively charged, thus repel each other due to the electrostatic force. Overcoming this repulsion costs a considerable amount of energy, known as the Coulomb barrier or fusion barrier energy.
Less energy will be needed to cause lighter nuclei to fuse, as they have less charge and thus a lower barrier energy, when they do fuse, more energy will be released. As the mass of the nuclei increase, there is a point where the reaction no longer gives off net energy—the energy needed to overcome the energy barrier is greater than the energy released in the resulting fusion reaction; the best fuel from an energy perspective is a one-to-one mix of tritium. The D-T mix has a low barrier because of its high ratio of neutrons to protons; the presence of neutral neutrons in the nuclei helps pull them together via the nuclear force, while the presence of positively charged protons pushes the nuclei apart via electrostatic force. Tritium has one of the highest ratios of neutrons to protons of any stable or moderately unstable nuclide—two neutrons and one proton. Adding protons or removing neutrons increases the energy barrier. A mix of D-T at standard conditions does not undergo fusion. In the hot, dense center of the sun, the average proton will exist for billions of years before it fuses.
For practical fusion power systems, the rate must be increased by heating the fuel to tens of millions of degrees, and/or compressing it to immense pressures. The temperature and pressure required for any particular fuel to fuse is known as the Lawson criterion; these conditions have been known since the 1950s. To meet the Lawson Criterion is difficult on Earth, which explains why fusion research has taken many years to reach the current high state of technical prowess. In a hydrogen bomb, the fusion fuel is heated with a separate fission bomb. A variety of mechanisms transfers the energy of the fission "primary" explosion into the fusion fuel. A primary mechanism is that the flash of x-rays given off by the primary is trapped within the engineered case of the bomb, causing the volume between the case and the bomb to fill with an x-ray "gas"; these x-rays evenly illuminate the outside of the fusion section, the "secondary" heating it until it explodes outward. This outward blowoff causes the rest of the secondary to be compressed inward until it reaches the temperature and density where fusion reactions begin.
The requirement of a fission bomb makes the method impractical for power generation. Not only would the triggers be prohibitively expensive to produce, but there is a minimum size that such a bomb can be built, defined by the critical mass of the plutonium fuel used, it seems difficult to build nuclear devices smaller than about 1 kiloton in yield, the fusion secondary would add to this. This makes it a difficult engineering problem to extract power from the resulting explosions. One of the PACER participants, John Nuckolls, began to explore what happened to the size of the primary required to start the fusion reaction as the size of the secondary was scaled down, he discovered that as the secondary reaches the miligram size, the amount of energy needed to spark it fell into the megajoule range. This was far below what was needed for a bomb, where the primary was in the tera
France the French Republic, is a country whose territory consists of metropolitan France in Western Europe and several overseas regions and territories. The metropolitan area of France extends from the Mediterranean Sea to the English Channel and the North Sea, from the Rhine to the Atlantic Ocean, it is bordered by Belgium and Germany to the northeast and Italy to the east, Andorra and Spain to the south. The overseas territories include French Guiana in South America and several islands in the Atlantic and Indian oceans; the country's 18 integral regions span a combined area of 643,801 square kilometres and a total population of 67.3 million. France, a sovereign state, is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre. Other major urban areas include Lyon, Toulouse, Bordeaux and Nice. During the Iron Age, what is now metropolitan France was inhabited by a Celtic people. Rome annexed the area in 51 BC, holding it until the arrival of Germanic Franks in 476, who formed the Kingdom of Francia.
The Treaty of Verdun of 843 partitioned Francia into Middle Francia and West Francia. West Francia which became the Kingdom of France in 987 emerged as a major European power in the Late Middle Ages following its victory in the Hundred Years' War. During the Renaissance, French culture flourished and a global colonial empire was established, which by the 20th century would become the second largest in the world; the 16th century was dominated by religious civil wars between Protestants. France became Europe's dominant cultural and military power in the 17th century under Louis XIV. In the late 18th century, the French Revolution overthrew the absolute monarchy, established one of modern history's earliest republics, saw the drafting of the Declaration of the Rights of Man and of the Citizen, which expresses the nation's ideals to this day. In the 19th century, Napoleon established the First French Empire, his subsequent Napoleonic Wars shaped the course of continental Europe. Following the collapse of the Empire, France endured a tumultuous succession of governments culminating with the establishment of the French Third Republic in 1870.
France was a major participant in World War I, from which it emerged victorious, was one of the Allies in World War II, but came under occupation by the Axis powers in 1940. Following liberation in 1944, a Fourth Republic was established and dissolved in the course of the Algerian War; the Fifth Republic, led by Charles de Gaulle, remains today. Algeria and nearly all the other colonies became independent in the 1960s and retained close economic and military connections with France. France has long been a global centre of art and philosophy, it hosts the world's fourth-largest number of UNESCO World Heritage Sites and is the leading tourist destination, receiving around 83 million foreign visitors annually. France is a developed country with the world's sixth-largest economy by nominal GDP, tenth-largest by purchasing power parity. In terms of aggregate household wealth, it ranks fourth in the world. France performs well in international rankings of education, health care, life expectancy, human development.
France is considered a great power in global affairs, being one of the five permanent members of the United Nations Security Council with the power to veto and an official nuclear-weapon state. It is a leading member state of the European Union and the Eurozone, a member of the Group of 7, North Atlantic Treaty Organization, Organisation for Economic Co-operation and Development, the World Trade Organization, La Francophonie. Applied to the whole Frankish Empire, the name "France" comes from the Latin "Francia", or "country of the Franks". Modern France is still named today "Francia" in Italian and Spanish, "Frankreich" in German and "Frankrijk" in Dutch, all of which have more or less the same historical meaning. There are various theories as to the origin of the name Frank. Following the precedents of Edward Gibbon and Jacob Grimm, the name of the Franks has been linked with the word frank in English, it has been suggested that the meaning of "free" was adopted because, after the conquest of Gaul, only Franks were free of taxation.
Another theory is that it is derived from the Proto-Germanic word frankon, which translates as javelin or lance as the throwing axe of the Franks was known as a francisca. However, it has been determined that these weapons were named because of their use by the Franks, not the other way around; the oldest traces of human life in what is now France date from 1.8 million years ago. Over the ensuing millennia, Humans were confronted by a harsh and variable climate, marked by several glacial eras. Early hominids led a nomadic hunter-gatherer life. France has a large number of decorated caves from the upper Palaeolithic era, including one of the most famous and best preserved, Lascaux. At the end of the last glacial period, the climate became milder. After strong demographic and agricultural development between the 4th and 3rd millennia, metallurgy appeared at the end of the 3rd millennium working gold and bronze, iron. France has numerous megalithic sites from the Neolithic period, including the exceptiona
A levitated dipole is a type of nuclear fusion reactor design using a superconducting torus, magnetically levitated inside the reactor chamber. The name refers to the magnetic dipole that forms within the reaction chamber, similar to Earth's or Jupiter's magnetospheres, it is believed that such an apparatus could contain plasma more efficiently than other fusion reactor designs. The Levitated Dipole Experiment was funded by the US Department of Energy's Office of Fusion Energy; the machine was run in a collaboration between Columbia University. Funding for the LDX was ended in November 2011 to concentrate resources on tokamak designs; the Earth's magnetic field is generated by the circulation of charges in the Earth's molten core. The resulting magnetic dipole field forms a shape with magnetic field lines passing through the Earth's center, reaching the surface near the poles and extending far into space above the equator. Charged particles entering the field will tend to follow the lines of force, moving south.
As they reach the polar regions, the magnetic lines begin to cluster together, this increasing field can cause particles below a certain energy threshold to reflect, begin travelling in the opposite direction. Such particles bounce forth between the poles until the collide with other particles. Particles with greater energy continue towards the Earth, impacting the atmosphere and causing the aurora; this basic concept is used in the magnetic mirror approach to fusion energy. The mirror uses a solenoid to confine the plasma in the center of a cylinder, two magnets at either end to force the magnetic lines closer together to create reflecting areas. One of the most promising of the early approaches to fusion, the mirror proved to be "leaky", with the fuel refusing to properly reflect from the ends as the density and energy were increased. Annoyingly, it was the particles with the most energy, those most to undergo fusion, that preferentially escaped. Research into large mirror machines ended in the 1980s as it became clear they would not reach fusion breakeven in a sized device.
The levitated dipole can be thought of, in some ways, as a toroidal mirror, much more similar to the Earth's field than the linear system in a traditional mirror. In this case, the confinement area is not the linear area between the mirrors, but the toroidal area around the outside of the central magnet, similar to the area around the Earth's equator. Particles in this area that move up or down see increasing magnetic density and tend to move back towards the equator area again; this gives the system some level of natural stability. Particles with higher energy, the ones that would escape a traditional mirror, instead follow the field lines through the hollow center of the magnet, recirculating back into the equatorial area again; this makes the Levitated Dipole unique. In those experiments, small fluctuations can cause significant energy loss. By contrast, in a dipolar magnetic field, fluctuations tend to compress the plasma, without energy loss; this compression effect was first noticed by Akira Hasegawa after participating in the Voyager 2 encounter with Uranus.
Adapting this concept to a fusion experiment was first proposed by Dr. Jay Kesner and Dr. Michael Mauel in the mid to late nineties; the pair raised money to build the machine. They achieved first plasma on Friday, August 13, 2004 at 12:53 PM. First plasma was done by levitating the dipole magnet and RF heating the plasma; the LDX team has since conducted several levitation tests, including a 40-minute suspension of the superconducting coil on February 9, 2007. Shortly after, the coil was damaged in a control test in February 2007 and replaced in May 2007; the replacement coil was inferior, a copper wound electromagnet, water cooled. Scientific results, including the observation of an inward turbulent pinch, were reported in Nature Physics; this experiment needed a special free-floating electromagnet, which created the unique "toilet-bowl" magnetic field. The magnetic field was made of two counter-wound rings of currents; each ring contained a 19-strand niobium-tin Rutherford cable. These looped around inside a Inconel magnet.
The donut was charged using induction. Once charged, it generated a magnetic field for an 8-hour period. Overall, the ring levitated 1.6 meters above a superconducting ring. The ring produced a 5-tesla field; this superconductor was encased inside a liquid helium, which kept the electromagnet below 10 kelvins. This design is similar to the D20 dipole experiment at Berkeley and the RT-1 experiment at the University of Tokyo; the dipole was suspended inside a mushroom-shaped vacuum chamber, about 5 meters in diameter and ~3 meters high. At the base of the chamber was a charging coil; this coil is used using induction. The coil exposing the dipole to a varying magnetic field. Next, the dipole is raised into the center of the chamber; this could be using the field itself. Around the outside of this chamber were Helmholtz coils, which were used to produce a uniform surrounding magnetic field; this external field would interact with the dipole field. It was in this surrounding field; the plasma forms inside the chamber.
The plasma is formed by heating a low pressure gas. The gas is heated using a radio frequency microwaving the plasma in a 17-kilowatt field; the machine was monitored
Not to be confused with the spherical tokamak, another topic in fusion research. A spheromak is an arrangement of plasma formed into a toroidal shape similar to a smoke ring; the spheromak contains large internal electric currents and their associated magnetic fields arranged so the magnetohydrodynamic forces within the spheromak are nearly balanced, resulting in long-lived confinement times without external fields. Spheromaks belong to a type of plasma configuration referred to as the compact toroids; the physics of the spheromak and of collisions between spheromaks is similar to a variety of astrophysical events, like coronal loops and filaments, relativistic jets and plasmoids. They are useful for studying magnetic reconnection events, when two or more spheromaks collide. Spheromaks are easy to generate using a "gun" that ejects spheromaks off the end of an electrode into a holding area, called the flux conserver; this has made them useful in the laboratory setting, spheromak guns are common in astrophysics labs.
These devices are confusingly, referred to as "spheromaks" as well. Spheromaks have been proposed as a magnetic fusion energy concept due to their long confinement times, on the same order as the best tokamaks when they were first studied. Although they had some successes during the 1970s and'80s, these small and lower-energy devices had limited performance and most spheromak research ended when fusion funding was curtailed in the late 1980s. However, in the late 1990s research demonstrated that hotter spheromaks have better confinement times, this led to a second wave of spheromak machines. Spheromaks have been used to inject plasma into a bigger magnetic confinement experiment like a tokamak; the difference between a field-reversed configuration and a spheromak is that a spheromak has an extra toroidal field. This field can run counterclockwise to the spinning plasma direction; the spheromak has undergone several distinct periods of investigation, with the greatest efforts during the 1980s, a reemergence in the 2000s.
A key concept in the understanding of the spheromak is magnetic helicity, a value H that describes the "twistedness" of the magnetic field in a plasma. The earliest work on these concepts was developed by Hannes Alfvén in 1943, which won him the 1970 Nobel Prize in Physics, his development of the concept of Alfvén waves explained the long-duration dynamics of plasma as electric currents traveling within them produced magnetic fields which, in a fashion similar to a dynamo, gave rise to new currents. In 1950, Lundquist experimentally studied Alfvén waves in mercury and introduced the characterizing Lundquist number, which describes the plasma's conductivity. In 1958, Lodewijk Woltjer, working on astrophysical plasmas, noted that H is conserved, which implies that a twisty field will attempt to maintain its twistiness with external forces being applied to it. Starting in 1959, Alfvén and a team including Lindberg and Jacobsen built a device to create balls of plasma for study; this device was identical to modern "coaxial injector" devices and the experimenters were surprised to find a number of interesting behaviors.
Among these was the creation of stable rings of plasma. In spite of their many successes, in 1964 the researchers turned to other areas and the injector concept lay dormant for two decades. In 1951 efforts to produce controlled fusion for power production began; these experiments used some sort of pulsed power to deliver the large magnetic forces required in the experiments. The current magnitudes and the resulting forces were unprecedented. In 1957 Harold Furth and Waniek reported on the dynamics of large magnets, demonstrating that the limiting factor in magnet performance was physical, they proposed winding these magnets in such a way that the forces within the magnet windings cancelled out, the "force-free condition". Although it was not known at the time, this is the same magnetic field as in a spheromak. In 1957 the ZETA machine started operation in the UK. ZETA was at that time by far the most powerful fusion device in the world, it operated until 1968. During its operation, the experimental team noticed that on occasion the plasma would maintain confinement long after the experimental run had ostensibly ended, although this was not studied in depth.
Years in 1974, John Bryan Taylor characterized these self-stable plasmas, which he called "quiescent". He developed the Taylor state equilibrium concept, a plasma state that conserves helicity in its lowest possible energy state; this led to a re-awakening of compact toroid research. Another approach to fusion was the theta pinch concept, similar to the z-pinch used in ZETA in theory, but used a different arrangement of currents and fields. While working on such a machine in the early 1960s, one designed with a conical pinch area and Wells found that the machine sometimes created stable rings of plasma. A series of machines to study the phenomenon followed. One magnetic probe measurement found the toroidal magnetic field profile of a spheromak. However, the theta-pinch failed to reach the high-energy conditions needed for fusion, most work on theta-pinch had ended by the 1970s; the key concept in fusion is the energy balance for any machine fusing a hot plasma. Net Power = Efficiency * This forms the basis of the Lawson criterion.
A nova remnant is made up of the material either left behind by a sudden explosive fusion eruption by classical novae, or from multiple ejections by recurrent novae. Over their short lifetimes, nova shells show expansion velocities of around 1000 km/s, whose faint nebulosities are illuminated by their progenitor stars via light echos as observed with the spherical shell of Nova Persei 1901 or the energies remaining in the expanding bubbles like T Pyxidis. Most novae require a close binary system, with a white dwarf and a main sequence, sub-giant, or red giant star, or the merging of two red dwarfs, so all nova remnants must be associated with binaries; this theoretically means these nebula shapes might be affected by their central progenitor stars and the amount of matter ejected by novae. The shapes of these nova nebulae are of much interest to modern astrophysicists. Nova remnants when compared to supernova remnants or planetary nebulae generate much less both in energy and mass, they can be observed for a few centuries.
Examples of novae displaying nebula shells or remnants include: GK Per, RR Pic, DQ Her, FH Ser, V476 Cyg, V1974 Cyg, HR Del and V1500 Cyg. Notably, more nova remnants have been found with the new novae, due to improve imaging technology like CCD and at other wavelengths. Planetary nebula Supernova remnant Hypatia Libyan desert glass T Pyxidis Nova Remnant Double-star systems cycle between big and small blasts Nova Remnant comparison table Nova Remnant
A spherical tokamak is a type of fusion power device based on the tokamak principle. It is notable for its narrow profile, or aspect ratio. A traditional tokamak has a toroidal confinement area that gives it an overall shape similar to a donut, complete with a large hole in the middle; the spherical tokamak reduces the size of the hole as much as possible, resulting in a plasma shape, spherical compared with a cored apple. The spherical tokamak is sometimes referred to as a spherical torus and shortened to ST; the spherical tokamak is an offshoot of the conventional tokamak design. Proponents claim. For this reason the ST has generated considerable interest since the late 1980s. However, development remains one generation behind traditional tokamak efforts like JET. Major experiments in the ST field include the pioneering START and MAST at Culham in the UK, the US's NSTX-U and Russian Globus-M. Research has questioned. Further research is needed to better understand. In the event that STs do not lead to lower cost approaches to power generation, they are still lower cost in general.
See background for fusion power The basic idea behind fusion is to force two suitable atoms close enough together that the strong force pulls them together to make a single larger atom. This process releases a considerable amount of binding energy in the form of high-speed subatomic particles like neutrons or beta particles. However, these same fuel atoms experience the electromagnetic force pushing them apart. In order for them to fuse, they much be pressed together with enough energy to overcome this coulomb barrier; the simplest way to do this is to heat the fuel to high temperatures, allow the Maxwell–Boltzmann distribution to produce a number of high-energy atoms within a larger, cooler mix. For the fusion to occur, the higher speed atoms have to meet, in the random distribution that will take time; the time will be reduced by increasing the temperature, which increases the number of high-speed particles in the mix, or by increasing the pressure, which keeps them closer together. The product of temperature and time produces the expected rate of fusion events, the so-called fusion triple product.
To be useful as a net energy exporter, the triple product has to meet a certain minimum condition, the Lawson criterion. In practical terms, the required temperatures are on the order of 100 million degrees; this leads to problems with the two other terms. However, at these temperatures the fuel is in the form of an electrically conductive plasma, which leads to a number of potential confinement solutions using magnetic or electrical fields. Most fusion devices use variations of these techniques. Tokamaks are the most researched approach within the larger group of magnetic fusion energy designs, they attempt to confine a plasma using powerful magnetic fields. Tokamaks confine their fuel at low pressure but high temperatures, attempt to keep those conditions stable for ever-increasing times on the order of seconds to minutes. Doing so, requires massive amount of power in the magnetic system, any way to reduce this improves the overall energy efficiency of the system. Ideally, the energy needed to heat the fuel would be made up by the energy released from the reactions, keeping the cycle going.
Anything over and above this amount could be used for power generation. This leads to the concept of the Lawson criterion, which delineates the conditions needed to produce net power; when the fusion fuel is heated, it will lose energy through a number of processes. These are related to radiating terms like blackbody radiation, conduction terms, where the physical interaction with the surrounding carries energy out of the plasma; the resulting energy balance for any fusion power device, using a hot plasma, is shown below. P net = η capture where: P net, is the net power out η capture, is the efficiency with which the plant captures energy, say though a steam turbine, any power used to run the reactor P fusion, is the power generated by fusion reactions a function of the rate of reactions P conduction, is the power lost through conduction to the reactor body P radiation, is the power lost as light, leaving the plasma through gamma radiationTo achieve net power, a device must be built which optimizes this equation.
Fusion research has traditionally focused on increasing the first P term: the fusion rate. This has led to a variety of machines that operate at higher temperatures and attempt to maintain the resulting plasma in a stable state long enough to meet the desired triple product. However, it is essential to maximize the η for practical r
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; the term was coined in 2002 with the release of a report by Rusi Taleyarkhan and collaborators that claimed to have observed evidence of sonofusion. The claim was surrounded by controversy, including allegations ranging from experimental error to academic fraud. Subsequent publications claiming independent verification of sonofusion were highly controversial. An investigation by Purdue University found that Taleyarkhan had engaged in falsification of independent verification, had included 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 the March 8, 2002 issue of the peer-reviewed journal Science, Rusi P. Taleyarkhan and colleagues at the Oak Ridge National Laboratory reported that acoustic cavitation experiments conducted with deuterated acetone showed measurements of tritium and neutron output consistent with the occurrence of fusion; the neutron emission was reported to be coincident with 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. A rebuttal by Taleyarkhan and 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 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 fusion reaction. In their response, the Taleyarkhan team provided detailed counter-arguments and concluded that the energy was "reasonably close" to that, 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, a much more sophisticated neutron detection device, 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 reported. The original report only claimed neutron emission from 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 was attempted. An article in Nature raised issues about the validity of the research and complaints from his Purdue colleagues. Charges of misconduct were raised, 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 participated in the paper just to overcome the criticism of one reviewer, 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 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 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 the background. When the same experiment was performed with non-deuterated