Diamond anvil cell



 

A diamond anvil cell (DAC) is a device used to exert extreme culets.

The device has been used to simulate the extreme pressures existing in the hearts of planets, creating new materials in the process. Notable examples include the non-molecular ice X[1], polymeric nitrogen[2] and MgSiO3 perovskite, thought to be the major component of the Earth's mantle.

Principle

The operation of the diamond anvil cell relies on a simple principle:

p=\frac{F}{A}

where p is the pressure, F the applied force, and A the area.

Therefore high pressure can be achieved by applying a moderate force on a sample with a small area, rather than applying a large force on a large area. In order to prevent deformation and even breakage of the anvils that apply the force, they must be made from a very hard and virtually incompressible material, such as diamond.

History

ruby pressure calibration. The DAC evolved to be the most powerful lab device for generating static high pressure. The range of static pressure attainable today extends to the estimated pressures at the Earth’s center (~360 GPa).

Components

There are many different DAC designs but all have three main components:

(1) The force-generating device — relies on the operation of either a lever arm, tightening screws, or pressure applied to a membrane. In all cases the force is uniaxial and is applied to the tables (bases) of the two anvils

(2) Two opposing pressure and to prevent dangerous strains.

(3) Gasket — a stresses at the edges of the culet.

Uses

Prior to the invention of the diamond anvil cell static high-pressure apparatus required large hydraulic presses which weighed several tonnes and required large specialised laboratories. The simplicity and compactness of the DAC mean that it can be accommodated in a wide variety of experiments. Some contemporary DACs can easily fit into a cryostat for low-temperature measurements, and for use with a superconducting electromagnet. In addition to being hard, X-rays.

A variant of the diamond anvil, the hydrothermal diamond anvil cell (HDAC) is used in experimental petrology/geochemistry for the study of aqueous fluids, silicate melts, immiscible liquids, mineral solubility and aqueous fluid speciation at geologic pressures and temperatures. The HDAC is sometimes used to examine aqueous complexes in solution using the synchrotron light source techniques EXAFS.

References

  1. ^ Compression of ice to 210 gigapascals: Infrared evidence for a symmetric hydrogen-bonded phase, A.F.Goncharov, V.V.Struzhkin, M.S.Somayazulu, R.J.Hemley and H.K.Mao, Science 273, p218-230 (1996)
  2. ^ Semiconducting non-molecular nitrogen up to 240 GPa and its low-pressure stability, M.Eremets, R.J.Hemley, H.K.Mao and E.Gregoryanz, Nature, 411 (2001)170-174
  • S. Block, and G. Piermarini: "The Diamond Cell Stimulates High-Pressure Research”, Physics Today 29, p. 44 (1976)
  • A. Jayaraman: “Diamond Anvil Cell and High-Pressure Physical Investigations”, Reviews of Modern Physics 55, p. 65 (1983)
  • A. Jayaraman: "Ultrahigh pressures", Reviews of Scientific Instruments 57, p. 1013 (1986)
  • D.J. Dunstan, and I.L. Spain: “The Technology of Diamond Anvil High-Pressure Cells”, Journal of Physics E: Scientific Instruments 22, p. 913-933 (1989)
  • M.I. Eremets: “High Pressure Experimental Methods”, Oxford Science Publication (1996)
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Diamond_anvil_cell". A list of authors is available in Wikipedia.