Fusion Power on Earth Using3

2He 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)

32He

Somewhere in the Solar System

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 → 3

1H+ 11H + 0.764 MeV

Neutron 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 + 3

2He → 42He+ 21

1p++12.86 MeV most promising aneutronic fusion process if we had any appreciable 3

2He 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.

32He + 3

2He → 42He+ 21

1p++12.86 MeV

Making 32He

• Primary way to make Tritium, hydrogen-3, heavy heavy hydrogen on earth; 6

3Li+n→42He(2.05 MeV)

+31T(2.75 MeV)

• Let Tritium decay: 31T =3

1H →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.

Binding Energy (MeV)/Nucleon

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

Neutron, n0: u+⅔ d-⅓ d-⅓, a baryon

Free Neutron Decay

• n0 → p+ + e− + νe • 1.67492729(28)×10−27 kg

939.565560(81) MeV/c2

1.0086649156(6) u• mean lifetime of 885.7±0.8 s (about 14

minutes, 46 seconds) • Neutrons are often stable in the nucleus.

Proton, p+: u+⅔ u+⅔ d-⅓, a baryon

Pion, π+: u+⅔ d⅓, a meson

Free Pion Decay

• Lifetime of 2.6×10−8 s. π+ → μ+ + νμ ; π− → μ− + νμ

with probability 0.999877, is a purely leptonic decay into a muon and a muon neutrino. π+ → e+ + νe ; π− → e− + νe second most common decay mode of a pion, with probability 0.000123.

• Lifetime of 8.4×10−17 s. 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

QuarksName Symbol Mass Mev/c2 Q (charge)

Up u 1.7 to 3.3 +2⁄3

Down d 4.1 to 5.8 −1⁄3

Charm c 1,270+70−90 +2⁄3

Strange s 101+29−21 −1⁄3

Top t 172,000±900 ±1,300 +2⁄3

Bottom b 4,190+180−60 −1⁄3

Quarks combining colorlessly to formMesons and Baryons

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

Gluons

•

The strengths of the weak interactions between the six quarks.

Leptons

• e− · e+ · μ− · μ+ · τ− · τ+ · νe · νe · νμ · νμ · ντ · ντ

Vector Bosons,W and Z Boson

Neutrinos, charge zero leptons: νe νμ ντ

Internet Resources

• Neutrinos • Neutrino oscillations• Weak Nuclear Force• Higgs mechanism