Pyroelectric fusion

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Pyroelectric fusion refers to the technique of using pyroelectric crystals to generate high strength electrostatic fields to accelerate deuterium ions (tritium might also be used someday) into a metal hydride target also containing deuterium (or tritium) with sufficient kinetic energy to cause these ions to undergo nuclear fusion. It was reported in April 2005 by a team at UCLA. The scientists used a pyroelectric crystal heated from −34 to 7 °C (−29 to 45 °F), combined with a tungsten needle to produce an electric field of about 25 gigavolts per meter to ionize and accelerate deuterium nuclei into an erbium deuteride target. Though the energy of the deuterium ions generated by the crystal has not been directly measured, the authors used 100 keV (a temperature of about 109  K) as an estimate in their modeling. [1] At these energy levels, two deuterium nuclei can fuse to produce a helium-3 nucleus, a 2.45 MeV neutron and bremsstrahlung. Although it makes a useful neutron generator, the apparatus is not intended for power generation since it requires far more energy than it produces. [2] [3] [4] [5]

Contents

History

The process of light ion acceleration using electrostatic fields and deuterium ions to produce fusion in solid deuterated targets was first demonstrated by Cockcroft and Walton in 1932 (see Cockcroft–Walton generator). That process is used in miniaturized versions of their original accelerator, in the form of small sealed tube neutron generators, for petroleum exploration.

The process of pyroelectricity has been known from ancient times. [6] The first use of a pyroelectric field to accelerate deuterons was in a 1997 experiment conducted by Drs. V.D. Dougar Jabon, G.V. Fedorovich, and N.V. Samsonenko. [7] This group was the first to utilize a lithium tantalate (LiTaO3) pyroelectric crystal in fusion experiments.

The novel idea with the pyroelectric approach to fusion is in its application of the pyroelectric effect to generate accelerating electric fields. This is done by heating the crystal from −34 °C to +7 °C over a period of a few minutes.

Nuclear D-D fusion driven by pyroelectric crystals was proposed by Naranjo and Putterman in 2002. [8] It was also discussed by Brownridge and Shafroth in 2004. [9] The possibility of using pyroelectric crystals in a neutron production device (by D-D fusion) was proposed in a conference paper by Geuther and Danon in 2004 [10] and later in a publication discussing electron and ion acceleration by pyroelectric crystals. [11] None of these later authors had prior knowledge of the earlier 1997 experimental work conducted by Dougar Jabon, Fedorovich, and Samsonenko which mistakenly believed that fusion occurred within the crystals. [7] The key ingredient of using a tungsten needle to produce sufficient ion beam current for use with a pyroelectric crystal power supply was first demonstrated in the 2005 Nature paper, although in a broader context tungsten emitter tips have been used as ion sources in other applications for many years. In 2010, it was found that tungsten emitter tips are not necessary to increase the acceleration potential of pyroelectric crystals; the acceleration potential can allow positive ions to reach kinetic energies between 300 and 310 keV. [12]

2005–2009

In April 2005, a UCLA team headed by chemistry professor James K. Gimzewski [13] and physics professor Seth Putterman utilized a tungsten probe attached to a pyroelectric crystal to increase the electric field strength. [14] Brian Naranjo, a graduate student working under Putterman, conducted the experiment demonstrating the use of a pyroelectric power source for producing fusion on a laboratory bench top device. [15] The device used a lithium tantalate (LiTaO3) pyroelectric crystal to ionize deuterium atoms and to accelerate the deuterons towards a stationary erbium dideuteride (Er D 2) target. Around 1000 fusion reactions per second took place, each resulting in the production of an 820 keV helium-3 nucleus and a 2.45 MeV neutron. The team anticipates applications of the device as a neutron generator or possibly in microthrusters for space propulsion.

A team at Rensselaer Polytechnic Institute, led by Yaron Danon and his graduate student Jeffrey Geuther, improved upon the UCLA experiments using a device with two pyroelectric crystals and capable of operating at non-cryogenic temperatures. [16] [17]

Pyroelectric fusion has been hyped in the news media, [18] which overlooked the work of Dougar Jabon, Fedorovich and Samsonenko. [7] Pyroelectric fusion is not related to the earlier claims of fusion reactions, having been observed during sonoluminescence (bubble fusion) experiments conducted under the direction of Rusi Taleyarkhan of Purdue University. [19] Naranjo of the UCLA team was one of the main critics of these earlier prospective fusion claims from Taleyarkhan. [20]

2010–present

The first successful results with pyroelectric fusion using a tritiated target was reported in 2010. [21] Putterman and Naranjo worked with T. Venhaus of Los Alamos National Laboratory to measure a 14.1 MeV neutron signal far above background.

See also

Related Research Articles

<span class="mw-page-title-main">Deuterium</span> Isotope of hydrogen with one neutron

Deuterium is one of two stable isotopes of hydrogen. The nucleus of a deuterium atom, called a deuteron, contains one proton and one neutron, whereas the far more common protium has no neutrons in the nucleus. Deuterium has a natural abundance in Earth's oceans of about one atom of deuterium among every 6,420 atoms of hydrogen. Thus deuterium accounts for approximately 0.0156% by number of all the naturally occurring hydrogen in the oceans, while protium accounts for more than 99.98%. The abundance of deuterium changes slightly from one kind of natural water to another.

<span class="mw-page-title-main">Nuclear fusion</span> Process of combining atomic nuclei

Nuclear fusion is a reaction in which two or more atomic nuclei, usually deuterium and tritium, combine to form one or more different atomic nuclei and subatomic particles. The difference in mass between the reactants and products is manifested as either the release or absorption of energy. This difference in mass arises due to the difference in nuclear binding energy between the atomic nuclei before and after the reaction. Nuclear fusion is the process that powers active or main-sequence stars and other high-magnitude stars, where large amounts of energy are released.

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.

<span class="mw-page-title-main">Fusor</span> An apparatus to create nuclear fusion

A fusor is a device that uses an electric field to heat ions to a temperature in which they undergo nuclear fusion. The machine induces a voltage between two metal cages, inside a vacuum. Positive ions fall down this voltage drop, building up speed. If they collide in the center, they can fuse. This is one kind of an inertial electrostatic confinement device – a branch of fusion research.

<span class="mw-page-title-main">Fusion power</span> Electricity generation through nuclear fusion

Fusion power is a proposed form of power generation that would generate electricity by using heat from nuclear fusion reactions. In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, while releasing energy. Devices designed to harness this energy are known as fusion reactors. Research into fusion reactors began in the 1940s, but as of 2023, no device has reached net power.

<span class="mw-page-title-main">Pyroelectricity</span> Voltage created when a crystal is heated

Pyroelectricity is a property of certain crystals which are naturally electrically polarized and as a result contain large electric fields. Pyroelectricity can be described as the ability of certain materials to generate a temporary voltage when they are heated or cooled. The change in temperature modifies the positions of the atoms slightly within the crystal structure, so that the polarization of the material changes. This polarization change gives rise to a voltage across the crystal. If the temperature stays constant at its new value, the pyroelectric voltage gradually disappears due to leakage current. The leakage can be due to electrons moving through the crystal, ions moving through the air, or current leaking through a voltmeter attached across the crystal.

<span class="mw-page-title-main">Neutron source</span> Device that emits neutrons

A neutron source is any device that emits neutrons, irrespective of the mechanism used to produce the neutrons. Neutron sources are used in physics, engineering, medicine, nuclear weapons, petroleum exploration, biology, chemistry, and nuclear power.

Muon-catalyzed fusion is a process allowing nuclear fusion to take place at temperatures significantly lower than the temperatures required for thermonuclear fusion, even at room temperature or lower. It is one of the few known ways of catalyzing nuclear fusion reactions.

<span class="mw-page-title-main">Inertial electrostatic confinement</span> Fusion power research concept

Inertial electrostatic confinement, or IEC, is a class of fusion power devices that use electric fields to confine the plasma rather than the more common approach using magnetic fields found in magnetic confinement fusion (MCF) designs. Most IEC devices directly accelerate their fuel to fusion conditions, thereby avoiding energy losses seen during the longer heating stages of MCF devices. In theory, this makes them more suitable for using alternative aneutronic fusion fuels, which offer a number of major practical benefits and makes IEC devices one of the more widely studied approaches to fusion.

<span class="mw-page-title-main">Neutron generator</span> Source of neutrons from linear particle accelerators

Neutron generators are neutron source devices which contain compact linear particle accelerators and that produce neutrons by fusing isotopes of hydrogen together. The fusion reactions take place in these devices by accelerating either deuterium, tritium, or a mixture of these two isotopes into a metal hydride target which also contains deuterium, tritium or a mixture of these isotopes. Fusion of deuterium atoms results in the formation of a helium-3 ion and a neutron with a kinetic energy of approximately 2.5 MeV. Fusion of a deuterium and a tritium atom results in the formation of a helium-4 ion and a neutron with a kinetic energy of approximately 14.1 MeV. Neutron generators have applications in medicine, security, and materials analysis.

<span class="mw-page-title-main">Aneutronic fusion</span> Form of fusion power

Aneutronic fusion is any form of fusion power in which very little of the energy released is carried by neutrons. While the lowest-threshold nuclear fusion reactions release up to 80% of their energy in the form of neutrons, aneutronic reactions release energy in the form of charged particles, typically protons or alpha particles. Successful aneutronic fusion would greatly reduce problems associated with neutron radiation such as damaging ionizing radiation, neutron activation, reactor maintenance, and requirements for biological shielding, remote handling and safety.

<span class="mw-page-title-main">Lithium tantalate</span> Chemical compound

Lithium tantalate (LiTaO3) is a perovskite which possesses unique optical, piezoelectric and pyroelectric properties which make it valuable for nonlinear optics, passive infrared sensors such as motion detectors, terahertz generation and detection, surface acoustic wave applications, cell phones and possibly pyroelectric nuclear fusion. Considerable information is available from commercial sources about this salt.

A dense plasma focus (DPF) is a type of plasma generating system originally developed as a fusion power device starting in the early 1960s. The system demonstrated scaling laws that suggested it would not be useful in the commercial power role, and since the 1980s it has been used primarily as a fusion teaching system, and as a source of neutrons and X-rays.

<span class="mw-page-title-main">ASDEX Upgrade</span>

ASDEX Upgrade is a divertor tokamak at the Max-Planck-Institut für Plasmaphysik, Garching that went into operation in 1991. At present, it is Germany's second largest fusion experiment after stellarator Wendelstein 7-X.

<span class="mw-page-title-main">Magnetized liner inertial fusion</span> Method of producing controlled nuclear fusion

Magnetized liner inertial fusion (MagLIF) is an emerging method of producing controlled nuclear fusion. It is part of the broad category of inertial fusion energy (IFE) systems, which drives the inward movement of fusion fuel, thereby compressing it to reach densities and temperatures where fusion reactions occur. Previous IFE experiments used laser drivers to reach these conditions, whereas MagLIF uses a combination of lasers for heating and Z-pinch for compression. A variety of theoretical considerations suggest such a system will reach the required conditions for fusion with a machine of significantly less complexity than the pure-laser approach. There are currently at least two facilities testing feasibility of the MagLIF concept, the Z-machine at Sandia Labs in the US and Primary Test Stand (PTS) located in Mianyang, China.

<span class="mw-page-title-main">Plasma-facing material</span>

In nuclear fusion power research, the plasma-facing material (PFM) is any material used to construct the plasma-facing components (PFC), those components exposed to the plasma within which nuclear fusion occurs, and particularly the material used for the lining the first wall or divertor region of the reactor vessel.

Helion Energy, Inc. is an American fusion research company, located in Everett, Washington. They are developing a magneto-inertial fusion technology to produce helium-3 and fusion power via aneutronic fusion, which could produce low-cost clean electric energy using a fuel that is derived exclusively from water.

Ion Reactor, is an invention by a British scientist.

Lattice confinement fusion (LCF) is a type of nuclear fusion in which deuteron-saturated metals are exposed to gamma radiation or ion beams, such as in an IEC fusor, avoiding the confined high-temperature gasses used in other methods of fusion.

Seth J. Putterman is an American physicist. He is known to have an eclectic approach to research topics that broadly revolves around energy-focusing phenomena in nonlinear, continuous systems, with particular interest in turbulence, sonoluminescence, sonofusion and pyrofusion.

References

  1. ↑ "Supplementary methods for "Observation of nuclear fusion driven by a pyroelectric crystal"" (PDF).
  2. ↑ "UCLA Crystal Fusion". rodan.physics.ucla.edu.
  3. ↑ "Physics News Update 729". Archived from the original on November 12, 2013.
  4. ↑ Coming in out of the cold: nuclear fusion, for real | csmonitor.com
  5. ↑ "Nuclear fusion on the desktop ... really!". NBC News.
  6. ↑ Sidney Lang, "Pyroelectricity: From Ancient Curiosity to Modern Imaging Tool", Physics Today, August, 2005, pp. 31-36, and Sidney B. Lang, "Sourcebook of Pyroelectricity", (London: Gordon & Breach, 1974)
  7. 1 2 3 Dougar Jabon, V.D.; Fedorovich, G.V.; Samsonenko, N.V. (1997). "Catalitically Induced D-D Fusion in Ferroelectrics". Brazilian Journal of Physics. 27 (4): 515–521. Bibcode:1997BrJPh..27..515D. doi: 10.1590/s0103-97331997000400014 .
  8. ↑ B. Naranjo and S. Putterman "Search for fusion from energy focusing phenomena in ferroelectric crystals" Archived 2006-05-13 at the Wayback Machine . UCEI Proposal, February 1, 2002
  9. ↑ James D. Brownridge and Stephen M. Shafroth, Archived 2006-09-03 at the Wayback Machine , 1 May 2004
  10. ↑ Jeffrey A. Geuther, Yaron Danon, “Pyroelectric Electron Acceleration: Improvements and Future Applications”, ANS Winter Meeting Washington, D.C, November 14 – 18, 2004
  11. ↑ "Double Crystal Fusion" Could Pave the Way for Portable Device, News Releases, Rensselaer Polytechnic Institute: 2005-2006: "NY Team Confirms UCLA Tabletop Fusion" Archived 2006-03-19 at the Wayback Machine . www.scienceblog.com
  12. ↑ Tornow, W.; Lynam, S. M.; Shafroth, S. M. (2010). "Substantial increase in acceleration potential of pyroelectric crystals". Journal of Applied Physics. 107 (6): 063302–063302–4. Bibcode:2010JAP...107f3302T. doi:10.1063/1.3309841. hdl: 10161/3332 .
  13. ↑ :: James K. Gimzewski ::. Chem.ucla.edu. Retrieved on 2013-08-16.
  14. ↑ B. Naranjo, J. K. Gimzewski and S. Putterman (from UCLA), "Observation of nuclear fusion driven by a pyroelectric crystal". Nature , April 28, 2005. See also a news article on this. Archived 2008-09-15 at the Wayback Machine
  15. ↑ Brian Naranjo, "Observation of Nuclear Fusion Driven by a Pyroelectric Crystal", A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Physics, University of California, Los Angeles, 2006, 57 pages, Dr. Seth Putterman, Committee Chair. No reference to the earlier experimental work of Jabon, Fedorovich and Samsonenko [2] is found in Dr. Naranjo's dissertation.
  16. ↑ Geuther, Jeffrey A.; Danon, Yaron (2005). "Electron and positive ion acceleration with pyroelectric crystals". Journal of Applied Physics. 97 (7): 074109–074109–5. Bibcode:2005JAP....97g4109G. doi:10.1063/1.1884252.
  17. ↑ Jeffrey A. Geuther, "Radiation Generation with Pyroelectric Crystals", A Thesis submitted to the Graduate Faculty of Rensselaer Polytechnic Institute in Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy in Nuclear Engineering and Science, Rensselaer Polytechnic Institute, Troy, New York, April 13, 2007, 176 pages, Dr. Yaron Danon, Thesis Adviser.
  18. ↑ Matin Durrani and Peter Rodgers "Fusion seen in table-top experiment" Archived 2005-04-29 at the Wayback Machine . Physics Web , April 27, 2005
  19. ↑ Taleyarkhan, R. P.; West, C. D.; Lahey, R. T.; Nigmatulin, R. I.; Block, R. C.; Xu, Y. (2006). "Nuclear Emissions During Self-Nucleated Acoustic Cavitation". Physical Review Letters. 96 (3): 034301. Bibcode:2006PhRvL..96c4301T. doi:10.1103/physrevlett.96.034301. PMID   16486709.
  20. ↑ Naranjo, B. (2006). "Comment on "Nuclear Emissions During Self-Nucleated Acoustic Cavitation"". Physical Review Letters. 97 (14): 149403. arXiv: physics/0603060 . Bibcode:2006PhRvL..97n9403N. doi:10.1103/physrevlett.97.149403. PMID   17155298. S2CID   31494419.
  21. ↑ Naranjo, B.; Putterman, S.; Venhaus, T. (2011). "Pyroelectric fusion using a tritiated target". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 632 (1): 43–46. Bibcode:2011NIMPA.632...43N. doi:10.1016/j.nima.2010.08.003.
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