Pocket-Sized Nuclear Fusion


Experimental vacuum system for crystal fusion.  Brian Naranjo, James K. Gimzewski and Seth Putterman, "Observation of nuclear fusion driven by a pyroelectric crystal," Nature, Vol. 434, Num. 7037, pp1115-1118 (2005).[ Read the paper and view supplemental materials (including video) on the Nature website.]

ABSTRACT: While progress in fusion research continues with magnetic and inertial confinement, alternative approaches—such as Coulomb explosions of deuterium clusters and ultrafast laser−plasma interactions—also provide insight into basic processes and technological applications. However, attempts to produce fusion in a room temperature solid-state setting, including 'cold' fusion and 'bubble' fusion, have met with deep skepticism. Here we report that gently heating a pyroelectric crystal in a deuterated atmosphere can generate fusion under desktop conditions. The electrostatic field of the crystal is used to generate and accelerate a deuteron beam (> 100 keV and >4 nA), which, upon striking a deuterated target, produces a neutron flux over 400 times the background level. The presence of neutrons from the reaction D + D -->He (820 keV) + n (2.45 MeV) within the target is confirmed by pulse shape analysis and proton recoil spectroscopy. As further evidence for this fusion reaction, we use a novel time-of-flight technique to demonstrate the delayed coincidence between the outgoing alpha-particle and the neutron. Although the reported fusion is not useful in the power-producing sense, we anticipate that the system will find application as a simple palm-sized neutron generator.

The combination of a tip and crystal has been the force behind many technological and scientific developments. From one end of technological history with the crystal (cat's whisker) radio and the gramophone to the more recent development of the scanning tunneling microscope, tips have played a key role. Even the first transistor consisted of two needles and a crystal. The power of a sharp metallic tip is at the heart of the work reported in Nature. The tip field ionizes and sends high energy beams of deuterium to strike the target and generate fusion.

  "So many of our dreams at first seem impossible, then they seem improbable, and then when we summon the will, they soon become inevitable." --Christopher Reeve


I started research related to controlled nuclear fusion in 1979 when I began a postdoctoral fellowship (1979-1983) in the  Plasma-Surface Interactions Group run by Professor. Stan Veprek at the  Anorganisches Chemie Insitut  in the University of Zurich, Switzerland. The research involved analysis of the scrape-off layer through deposition and erosion by high energy bombardment of the first wall of a Tokamak. The Tokamak was situated at the Centre de Recherches en Physique des Plasmas, École Polytechnique Fédérale de Lausanne, and my experiments were conducted on the TCA machine which was designed to explore auxiliary plasma heating using Alfven waves. In the eighties there was much activity world wide on the dream of using nuclear fusion as a viable alternative energy source. As such the TCA machine was enormous and just firing up the device used up as much power as the energy consumption of Lausanne itself.  Much later, I visited a researcher in Tokyo who was still attempting to do cold fusion and he called the work “Confusion”.


In 1983 I left the fusion project and joined IBM Zurich Research Laboratories to work on the newly invented Scanning Tunneling Microscope (STM). This work led to a series of experiments where I researched the properties of sharp metallic tips as local sources of electrons, photons, ions and atoms. In particular, the creation of sharp tips and the imaging of tips were also being researched by a fellow researcher at the laboratory Han Werner Fink. Using a method known as Field Ionization Microscopy, it was possible to image tips with atomic resolution using ions--even hydrogen has been reported. We developed methods for STM tip production using these basic methods and explored phenomena such a Gündlach resonances which where electron standing waves generated between a tip and surface. Later we used the Field emission process itself to generate Auger electron emission and finally moved on to the creation of photons using electron tunneling. The latter research was particularly intense and resulted in a series of ground breaking publications. The research on tips also led me to work with Professor Jurgen K. Sass who was then at the Fritz Haber Institute of the Max Planck Gesellschaft in Berlin. Jurgen specialized in electrochemistry and the emission of light using a technique he developed called CTRIPS.  In 1989, like many scientists, the controversial cold-fusion claims made by Stanley Pons and Martin Fleischmann naturally stirred our interest. This led us to playfully think of creating nuclear fusion by crashing a tip into a surface under electrochemical conditions. This seems now to be a ridiculous notion, but I had learned from working in STM that seemingly impossible and apparently ridiculous ideas sometimes do work. This was an example of what experimentation is all about.

The IBM Research laboratories in Zurich during the early 80’s represented one of the most exciting places to be doing science. The birth of the STM by Binnig and Rohrer and later HiTc superconductivity by Bednorz and Muller are examples of the Nobel Prize winning recognition and the atmosphere of creativity that existed there. The use of a sharp tip to resolve atoms, to explore their electronic structure on an individual basis was and still is something that made the concept of Nanotechnology real and tangible. The concepts of optics and lenses were replaced by local tactile sesing.  HiTc demonstrated another paradigm shift in moving from a metal to an oxide to achieve superconductivity. My own research on tip has spanned a wide range of experiments from the measurement of the electrical “resistance” of a single atom contact, to the creation of electron standing waves to light and electron emission phenomena.

The nuclear fusion story continued when I visited Japan for the first time in 1995.  I spent five weeks in Japan as an Invited Guest Scientist (STA Fellow) International Research Fellowship based on my earlier work on plasma surface interactions for fusion research through the Science and Technology Agency (STA) at the then National Research Institute for Metals in Tsukuba, Japan. I was invited by Kenji Morita, director for Nuclear Research at the Atomic energy Agency Bureau of the STA. It was through this fellowship that I was able to link up with my old friend Masahiro Kitajima with whom I had collaborated on research work relating to hydrogen plasma-metal interactions.


Arriving at UCLA, I remember meeting Seth in his lab where I first saw sonoluminescence in action. It was so beautiful to again see visible photons emitted from these tiny collapsing bubbles. It was some time later that he informed me of X-ray emission by gently heating ferroelectric crystals. I set up an ultra high vacuum system straight away and we were the recipients of a few small grants aimed at exploring the creation of local X-ray emission. I was interested to generate localized field emission of electrons from a tip mounted on the crystal to perform local chemical analysis using energy dispersive X-ray analysis. Since the ferroelectyric crystal is also piezoelectric it seems possible to perform atomic force microscopy in conjunction with chemical analysis. The experiments led to new ides. In one we simple took dental X-ray film and use a small pyroelectric system to create images of a wire mesh. That work indicated the possibility to create point sources of X-rays and perhaps a new form of “Projection Microscopy”. It was the wild discussion on fusion that really got me excited and the possibility to generate ion beams that excited me most though. Recalling Muller’s Field Ion Microscope it seemed clear that a high enough positive potential on the tip would enable tunneling of electrons from gas phase deuterium to the tip there by creating positively charged ions that would be accelerated to the target. It turned out that as expected the sharpest tips were not the best for they would emit at lower potentials so an optimum value of around 100nm in radius was able to generate fusion events.

Selected publications 1984-1986 resulting from experiments performed  on the TCA Tokamak in Lausanne Switzerland

  “Impurity Recycling and Retention on Au and C Surfaces Exposed to the Scrape-Off-Layer of the TCA Tokamak,” J.K. Gimzewski, S. Vepřek, F. Hofmann, Ch. Hollenstien, J.B. Lister and A. Pochelon, P. Groner. Journal of Vacuum Science Technology A 4(1), 90-96 (1986)
  “Hydrogen Trapping in Zirconium under Plasma Conditions,” K. Yamashita, J.K. Gimzewski and S. Vepřek. Journal of Nuclear Material 128/129, 705-707 (1984)
   “Investigation of Impurity Retention, Implantation and Sputtering Phenomena on Au and C Surfaces Exposed to the Scrape-Off-Layer,” J.K. Gimzewski and S. Vepřek. Journal of Nuclear Material 128/129, 703-704 (1984)
  “Scrape-Off Measurements During Alfvén Wave Heating in the TCA Tokamak,” F. Hofmann, Ch. Hollenstein, B. Joyce, A. Lietti, J.B. Lister, A. Pochelon, J.K. Gimzewski and S. Vepřek. Journal of Nuclear Material 121, 22-28 (1984)
   “Impurity Deposition Profiles in the Plasma Edge of the TCA Tokamak,” J.K. Gimzewski, M. Braun, R.J. Brewer, S. Vepřek, H. Stüssi, F. Hofmann, J.B. Lister and A. Pochelon. Physica Scripta 30, 271-278 (1984)
  “A Novel Method for the Determination of the Energies of Impurity Ions Bombarding a Solid Surface Exposed to a Low-Pressure Plasma,” J.K. Gimzewski and S. Vepřek.  J. Vac. Sci. Technol. A 2(1), 35-39 (1984)