Thanks to Michelangelo de Meo for posting a link on the Journal of Nuclear Physics to a new paper published in the Physics of Plasma journal titled “Evidence of nuclear fusion neutrons in an extremely small plasma focus device operating at 0.1 Joules”. Authors are Leopoldo Soto, Cristián Pavéz José, Moreno, Luis Altamirano, Luis Huerta, Mario Barbaglia, Alejandro Clausse, and Roberto E. Mayer, from Chile and Argentina.
Here’s the abstract:
“We report on D-D fusion neutron emission in a plasma device with an energy input of only 0.1 J, within a range where fusion events have been considered very improbable. The results presented here are the consequence of scaling rules we have derived, thus being the key point to assure the same energy density plasma in smaller devices than in large machines. The Nanofocus (NF)—our device—was designed and constructed at the P4 Lab of the Chilean Nuclear Energy Commission. Two sets of independent measurements, with different instrumentation, were made at two laboratories, in Chile and Argentina. The neutron events observed are 20σ greater than the background. The NF plasma is produced from a pulsed electrical discharge using a submillimetric anode, in a deuterium atmosphere, showing empirically that it is, in fact, possible to heat and compress the plasma. The strong evidence presented here stretches the limits beyond what was expected. A thorough understanding of this could possibly tell us where the theoretical limits actually lie, beyond conjectures. Notwithstanding, a window is thus open for low cost endeavours for basic fusion research. In addition, the development of small, portable, safe nonradioactive neutron sources becomes a feasible issue.” (Emphasis added)
Here’s an image from the paper with the explanation:
“(a) A sketch of the NF discharge device. The driven capacitor (5 nF) is composed of two parallel plates (lower plate: anode; upper plate: cathode). A 0.42 mm diameter copper cylinder is covered with quartz, attached to the centre of the anode plate, and passes through a small hole in the cathode centre. Plasma is formed between the top of the anode and the cathode base. (b) The NF chamber (pointed in the photograph). (c) A time-integrated photograph of the discharge. Note the bright spot on the anode top.”