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GLOSSARY OF HIGH ENERGY WEAPONS TERMS

ALPHA PARTICLE

Helium nuclei. Not very penetrating. Stopped by epidermis.

BECQUEREL

Symbol: Bq 1 disintegration/second. 1 Curie = 3.7 x 10^10 Bq. Unit of activity. Things with small half-lives have the biggest activity.

BERYLLIUM

Symbol: Be Element 4 with atomic weights b/w 6 and 11. A neutron reflector and neutron source. Has low thermal neutron absorption cross section. Has high neutron scattering cross section. Be has the highest number of atoms / c.c. than any other element. Absorbs high energy neutrons to become a neutron source. Used in the core of boosted fission devices.

number 4 symbol Be name Beryllium density 1.85 heatVapor 73.9 heatFusion 2.8 elecConduct .25 thermalConduct .38 specificHeat .45 weight 9.012182 boilPoint 2472 deg C meltPoint 1289 deg C thermalConduct 2.01 specificGrav 1.848 (20 deg C) valence 2 configuration [He] 2s^2

BETA PARTICLE

Electrons, more penetrating than alphas. Can go through air, but are stopped by protective clothing.

BETA DECAY

Radioactive emission of an electron (beta particle) from a nucleus.

BOOSTING

Injecting the hollow core of a fissile weapon with T and D gases, soon after core implosion and fission initiation. Done to improve efficiency - there is a synergy b/w fission and fusion reactions.

DEUTERIUM

Symbol: D Heavy hydrogen isotope. Atomic number of 1, atomic weight of 2. i.e. nucleus has 1 proton, 1 neutron. Deuterium is not radioactive. Found as 1/6000 of tap water. Nuclear fuel used in fusion into helium.

GAMMA RAY

Short wavelength electromagnetic radiation, extremely high energy light. Highly penetrating. Can go through inches of steel or lead. Need metres of lead for protection.

GRAY

Symbol: Gy SI unit for 1 Joule deposited/kilogram of flesh. 1 Rad = 0.01 Gy.

ION

Atom stripped of its electron cloud.

INERTIAL CONFINEMENT

A technique which compresses a mass of fusion fuel, thereby increasing the probability and rate of fusion. Abbreviation: ICF

LEVITATION

Method of separating the pusher and core so that there is an air gap in between. This lets the pusher develop momentum (and maximises impulse) as the pusher implodes.

LITHIUM

Symbol: Li Element 3 with atomic weights b/w 5 and 9. Used as a fusion fuel. It is usually compounded with deuterium to form Li-6D. Neutron bombardment transforms Li into T. THe T fuses with the D to release He nuclei, more neutrons, and radiation.

LITHIUM 6 DEUTERIDE

Called "Liddy" by Igor Kurchatov its discoverer, it serves as a dry fuel in secondaries.

MEGATON

1,000,000 tons of TNT. 1 ton of TNT = 4.184^9 J. [From 'A Physicist's Desk Reference', Ed. Herbert L. Anderson]

NEUTRON

Chargeless particle, and highly penetrating due to this property. It hardly interacts, and hence is difficult to block. Can only be blocked by metres of concrete or deep water. Neutron absorption by nuclei can make the nuclei radioactively unstable.

NUCLEON

A proton or neutron in a nucleus.

ORALLOY

Symbol: Oy Oak Ridge Alloy, about 93.5% U-235.

PLUTONIUM

Sumbol: Pu Element 94 with atomic weights b/w 232 and 246. Radioactive, man-made. Half- life is 24,360yrs, and it alpha decays. Pu-239 metal is used in weapons.

number 94 symbol Pu name Plutonium weight [244] boilPoint 3230 deg C meltPoint 640 deg C heatVapor heatFusion elecConduct thermalConduct 0.0670 specificHeat specificGrav (alpha modification) 19.84 (25 deg C) valence 3, 4, 5, or 6 configuration [Rn] 5f^6 7s^2

RAD

Radiation Absorbed Dose, unit for measuring specific amounts of radiation absorbed by human tissue.

REM

Radiation Equivalent Man, measures biological damage done to tissue by specific amounts of radiation. The type of radiation is taken into account. For beta and gamma radiation, 1 RAD = 1 REM. For neutrons and alphas, 1 RAD = up to 20 REM, depending on particle energy. Low rad dosages are a few REM, high doses are > 100 REM. High doses give rise to immediate radiation sickness: hypodermal bleeding, hair loss, sickness. Under 25 REM, no short term effects are observed. In the long term, however, it will lead to greater possibility for cancer and genetic abnormality in offspring.

ROENTGEN

Symbol: R or r

Unit for measuring ionising radiation in air. Replaced by the Coulomb/kg. 1 roentgen = 2.58 x 10^-4 C/kg.

SHAKE

10 ns

SIEVERT

Symbol: Sv SI unit defined as Gy x Quality_factor. 1 REM = 0.01 Sv. Unit for dose equivalent. QF of gammas and betas is 1, QF for alphas is 20. So absorbed dose of 1 Gy of gammas = 1 Sv, whereas the dose of 1 Gy of alphas is 20 Sv. Background rad is 0.03 Sv.

SPARKPLUG

Oy or Pu-239 rod used as a fission igniter in a fusion cell. When compressed and bombarded at one end by neutrons, it fissions. It heats the surrounding compressed fusion fuel, and provides neutrons for T generation.

TRITIUM

Symbol: T Heavy hydrogen isotope. Atomic number of 1, atomic weight of 3. i.e. nucleus has 1 proton, 2 neutrons. Tritium is radioactive, with a half- life of 12.3yrs. Not found in Nature. Produced via neutron bombardment of Li.

URANIUM

Symbol: U Element 92 with atomic weights b/w 227 and 240. The U-235 and U-238 isotopes are used in weapons. U-238 produces Pu-239 via neutron bombardment in reactors. A heavy, silvery-white metal which is pyrophoric (spontaneous ignition) when finely divided. Highly corrosive to most materials when in metallic vapour form. Melting point: 1132 C. Boiling point: 3818 C. Has 6 electrons in highest shell, contributing to a complicated chemistry for U.

number 92 symbol U name Uranium weight 238.0289 boilPoint 4134 deg C meltPoint 1135 deg C heatVapor heatFusion elecConduct thermalConduct 0.275 specificHeat specificGrav ~18.95 valence 2, 3, 4, 5, or 6 configuration [Rn] 5f^3 6d 7s^2

URANIUM HEXAFLUORIDE

Symbol: UF6 Used in separation techniques since there is only 1 isotope of F. Molecular weight is 349 or 352, corresponding to U-235 and U-238 respectively. Highly symmetrical moelcule. Fluorines arranged arround central U atom, along the 3 perpendicular axes. UF6 is highly reactive, especially against water and many organic compounds. Strong fluorinating agent. Corrosive to most metals. Only Ni or Al and their alloys are suitable for UF6 handling in separators. Colorless solid at room temp. At room pressure, it sublimes at 56.5 C. cf dry ice.

1994

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