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Fusion Power on Earth Using 3 2 He from somewhere in the Solar System: if NASA and DOE ever cooperate!. Dr. Harold Williams Google “Montgomery College Planetarium” http:// montgomerycollege.edu /Departments/planet . Tokamak à Configuration Variable (TCV). 3 2 He.
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Fusion Power on Earth Using32He from somewhere in the Solar System: if NASA and DOE ever cooperate! Dr. Harold Williams Google “Montgomery College Planetarium” http://montgomerycollege.edu/Departments/planet
Abundance of 32He • Earth 0.000137% (% He on Earth) • Moon embedded in the upper layer of regolith by the solar wind over billions of years) and the solar system's gas giants (left over from the original solar nebula), though still low in quantity (28 ppm of lunar regolith is helium-4 and from 0.01 ppm to 0.05 ppm is helium-3 • Mars in the cold trap on poles? • Jupiter, Saturn, and other gas giants • Solar Nebulae
Some Earthly Uses of 32He • Giorgio Frossati, president of the Dutch dilution refrigerator manufacturer Leiden Cryogenics, says he recently paid $2150 per liter for 50 liters=6.7grams. • n0 + 32He → 31H+ 11H + 0.764 MeVNeutron Detectors; Homeland Security Use • Useful nuclei for neutron detection 3He, 6Li, 10B, 233U, 235U, 237Np and 239Pu.
Some Current Problems • DOE begins rationing helium-3, Physics Today on June 2010 page 22
Fusion on Earth with some Neutrons • Seems to have been 5 decades away since 1958. • Neutrons are the problem unless you want to blow things up! • Except in fission reactors neutrons can be thermalized in water and then there is no problem. Fusion occurs in a hot plasma many millions of degrees (so you can overcome the electrical repulsion of the positive charged nuclei) and there is no water in such environments to thermalize.
Some Future Uses of 32He • 32He + 32He → 42He+ 211p++12.86 MeV most promising aneutronic fusion process if we had any appreciable 32He fuel. • Mining the Moon in Technology Review published by MIT on August 23, 2007 • At the 21st century's start, few would have predicted that by 2007, a second race for the moon would be under way. Yet the signs are that this is now the case. Furthermore, in today's moon race, unlike the one that took place between the United States and the U.S.S.R. in the 1960s, a full roster of 21st-century global powers, including China and India, are competing.
Making 32He • Primary way to make Tritium, hydrogen-3, heavy heavy hydrogen on earth; 63Li+n→42He(2.05 MeV)+31T(2.75 MeV) • Let Tritium decay: 31T =31H →32He++e−+νe+ 18.6 keV; 4,500±8 days (approximately 12.32 years) • Beta particles from tritium can penetrate only about 6.0 mm of air, and they are incapable of passing through the dead outermost layer of human skin. Tritium is not good for you if you inhale or eat it.
Some Internet Resources • Helium, second most common element in the universe • Helium-3, subject of this presentation • Helium-4, nucleus is an alpha particle • Aneutronic fusion, possibilities • Periodic Table of the Elements from Radiochemistry Society • The Berkeley Laboratory Isotopes Project’s • Contemporary Physics Education Projects
Feynman Diagram of thedecay of the Neutron, Weak Nuclear Force
Free Neutron Decay • n0 → p+ + e− + νe • 1.67492729(28)×10−27kg939.565560(81) MeV/c21.0086649156(6) u • mean lifetime of 885.7±0.8 s (about 14 minutes, 46 seconds) • Neutrons are often stable in the nucleus.
Free Pion Decay • Lifetime of 2.6×10−8s. π+ → μ+ + νμ ; π− → μ− + νμwith probability 0.999877, is a purely leptonic decay into a muon and a muon neutrino. π+ → e+ + νe ; π− → e− + νesecond most common decay mode of a pion, with probability 0.000123. • Lifetime of 8.4×10−17s. π0 → 2 γ with probability 0.98798 and π0 → γ + e− + e+with probability 0.01198. • Virtual Pions are what holds the protons and neutrons together in the nucleus.
Standard Model of Particles SU(3)xSU(2)xU(1): Strong, Weak, ElectroMagnetism
Baryons • List of Baryons: some baryons N (p ·n) ·Δ ·Λ ·Σ ·Ξ ·Ω
Mesons • List of Mesons: some mesons π ·ρ ·η ·η′ ·φ ·ω ·J/ψ ·ϒ ·θ ·K ·B ·D ·T
The strengths of the weak interactions between the six quarks.
Leptons • e− ·e+ ·μ− · μ+ ·τ− · τ+ ·νe · νe ·νμ · νμ ·ντ · ντ
Neutrinos, charge zero leptons: νeνμντ Internet Resources • Neutrinos • Neutrino oscillations • Weak Nuclear Force • Higgs mechanism