Argon

Arargon gas 40 Ar 36 argon18Ar + areargon (Ar)argon isotope ratiosargon-40
Argon is a chemical element with the symbol Ar and atomic number 18.wikipedia
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Thermal conductivity

heat conductivitythermalconductivity
Argon and krypton, gases denser than air, are often used in insulated glazing (double paned windows) to improve their insulation characteristics.

AIM-9 Sidewinder

SidewinderAIM-9AIM-9X
Compressed argon gas is allowed to expand, to cool the seeker heads of some versions of the AIM-9 Sidewinder missile and other missiles that use cooled thermal seeker heads.
To cool the seeker head, a 5000 psi argon bottle (TMU-72/B or A/B) is carried internally in Air Force AIM-9L/M variants, while the Navy uses a rail-mounted nitrogen bottle.

Mercury (planet)

MercuryMercurioplanet Mercury
The atmospheres of Mars, Mercury and Titan (the largest moon of Saturn) contain argon, predominantly as, and its content may be as high as 1.93% (Mars).

Titanium

Tititanium oretitanian
Argon is used in some types of arc welding such as gas metal arc welding and gas tungsten arc welding, as well as in the processing of titanium and other reactive elements.
After extensive purification by fractional distillation, the TiCl 4 is reduced with 800 C molten magnesium in an argon atmosphere.

WIMP Argon Programme

WARP
Dark-matter detectors currently operating with liquid argon include DarkSide, WArP, ArDM, microCLEAN and DEAP.
It aims to detect nuclear recoils in liquid argon induced by weakly interacting massive particles (WIMP) through scintillation light; the apparatus can also detect ionization so to exclude interactions of photons and electrons.

ICARUS experiment

ICARUSICARUS (experiment)ICARUS collaboration
Neutrino experiments include ICARUS and MicroBooNE, both of which use high-purity liquid argon in a time projection chamber for fine grained three-dimensional imaging of neutrino interactions.
After first runs at Pavia in 2001, the ICARUS T600 detector at Gran Sasso, filled with 760 tons of liquid argon, started operation in 2010.

Plasma globe

plasma lampnovelty plasma lampplasma ball
It is used for the specific way it ionizes and emits light, such as in plasma globes and calorimetry in experimental particle physics.
Although many variations exist, a plasma lamp is usually a clear glass sphere filled with a mixture of various gases (most commonly neon, sometimes with other noble gases such as argon, xenon and krypton) at nearly atmospheric pressure.

Time projection chamber

time projectiontime-projection chamberTPC
Neutrino experiments include ICARUS and MicroBooNE, both of which use high-purity liquid argon in a time projection chamber for fine grained three-dimensional imaging of neutrino interactions.
In 1977, Carlo Rubbia devised a liquid-argon time projection chamber, or LArTPC.

Variable Specific Impulse Magnetoplasma Rocket

VASIMRplasma enginespace tug/orbital transfer vehicle
Argon is used as a propellant in the development of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR).
The propellant, a neutral gas such as argon or xenon, is injected into a hollow cylinder surfaced with electromagnets.

Incandescent light bulb

incandescent lampfilamentincandescent light
Argon is also used in incandescent, fluorescent lighting, and other gas-discharge tubes.
Filling a bulb with an inert gas such as argon or nitrogen slows down the evaporation of the tungsten filament compared to operating it in a vacuum.

Dark matter

dark matter detectiondark-mattermissing mass
Liquid argon is used as the target for neutrino experiments and direct dark matter searches.
Noble liquid detectors detect scintillation produced by a particle collision in liquid xenon or argon.

Cryosurgery

cryoprobecryotherapyapplication of cold
Cryosurgery procedures such as cryoablation use liquid argon to destroy tissue such as cancer cells.
Recent advances in technology have allowed for the use of argon gas to drive ice formation using a principle known as the Joule-Thomson effect.

Arc welding

arc welderArcarc welders
Argon is used in some types of arc welding such as gas metal arc welding and gas tungsten arc welding, as well as in the processing of titanium and other reactive elements.
Porosity and brittleness were the primary problems and the solutions that developed included the use of hydrogen, argon, and helium as welding atmospheres.

Sputter deposition

magnetron sputteringsputteringsputtered
Argon gas is also commonly used for sputter deposition of thin films as in microelectronics and for wafer cleaning in microfabrication.
(As the target material is depleted, a "racetrack" erosion profile may appear on the surface of the target.) The sputter gas is typically an inert gas such as argon.

Gas chromatography

gas chromatographgas-liquid chromatographyGC
Argon may be used as the carrier gas in gas chromatography and in electrospray ionization mass spectrometry; it is the gas of choice for the plasma used in ICP spectroscopy.
Typical carrier gases include helium, nitrogen, argon, hydrogen and air.

Dry suit

drysuitdry suitsdrysuits
Argon is also used in technical scuba diving to inflate a dry suit because it is inert and has low thermal conductivity.
Using a small (1-2 litre), dedicated cylinder avoids these complications; usually this will contain air but argon may be used instead.

E number

E-numberEE numbers
Argon is used to displace oxygen- and moisture-containing air in packaging material to extend the shelf-lives of the contents (argon has the European food additive code E938).

MicroBooNE

Neutrino experiments include ICARUS and MicroBooNE, both of which use high-purity liquid argon in a time projection chamber for fine grained three-dimensional imaging of neutrino interactions.
MicroBooNE's two main physics goals are to investigate the MiniBooNE low-energy excess and neutrino-argon cross sections.

Oxygen–argon ratio

In chemistry, a sample's oxygen–argon ratio (or oxygen/argon ratio) is a comparison between the concentrations of oxygen (O 2 ) and the noble gas argon (Ar), either in air or dissolved in a liquid such as seawater.

Insulated glazing

double glazingdouble glazeddouble-glazed
Argon is used for thermal insulation in energy-efficient windows.
Monatomic gases such as argon, krypton and xenon are often used since (at normal temperatures) they do not carry heat in rotational modes, resulting in a lower heat capacity than poly-atomic gases.

Microfabrication

microfabricatedMicroengineeringfabrication
Argon gas is also commonly used for sputter deposition of thin films as in microelectronics and for wafer cleaning in microfabrication.
Dry cleaning methods include oxygen and argon plasma treatments to remove unwanted surface layers, or hydrogen bake at elevated temperature to remove native oxide before epitaxy.

Atomic number

proton numberZatomic numbers
Argon is a chemical element with the symbol Ar and atomic number 18.

Periodic table

periodic table of elementsperiodic table of the elementsperiodic system
It is in group 18 of the periodic table and is a noble gas.

Parts-per notation

ppmparts per millionppb
Argon is the third-most abundant gas in the Earth's atmosphere, at 0.934% (9340 ppmv).

Water vapor

water vapourvaporevaporation
It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv).