The force in diamond anvil cells (DACs) can be generated through several mechanisms. The most common designs are screw-driven and gas membrane-driven systems. Other approaches include lever-arm designs, the turnbuckle principle, and elastic deflection of DAC plates using a gearbox.

A screw-driven diamond anvil cell is the traditional design for generating high pressures. It uses mechanical screws to press the two diamond anvils together. Typically, two or more opposed screws with left- and right-handed threads apply force to the cell’s piston, thereby generating pressure between the anvils. The screws are tightened manually, often with a torque wrench.

SymmDAC 60 

Diacell® OmniDAC 

A gas membrane-driven diamond anvil cell uses a flexible membrane pressurized with gas to control the applied force. As the gas pressure increases, the membrane expands and pushes the piston, bringing the two diamond anvils closer together. Common gases used for this purpose include argon and helium.

The key components needed for such a set up are:

• Piston – cylinder diamond anvil cell (see Diacell®Bragg-LT(G) Plus; Diacell® HeliosDAC Plus 
• Gas membrane;
• Gas membrane controller;
• A high pressure gas bottle and high pressure gas regulator.

These diamond anvil cells are based on the conventional Mao-Bell design and use a combination of lever arms and Belleville springs as a mean of exerting pressure. The diamond anvil cell is a piston-cylinder DAC. The lever-arm drive comprises two rigid arms connected to a screw through a presser plate at one end and a pressing plate linked to the DAC piston at the other. When the screw is tightened, the force—regulated by Belleville spring washers—is transmitted through the lever system to the diamond anvils, compressing the sample.  The lever-arm drive can often be detached for easier integration with spectrometers or optical setups.

The Almax easyLab LeverDAC Series includes three models: the LeverDAC Mini, Maxi and Mega which respectively enable maximum pressures of 30, 50 and 100 GPa.

 LeverDAC Maxi – Lever Arm Driven DAC

The turnbuckle diamond anvil cell consists of a cylindrical body (the buckle) and two end seats (eyelets) with left- and right-hand threads, each fitted with a diamond anvil. The cell operates on the turnbuckle principle: rotating the body causes both seats to move simultaneously toward or away from each other, depending on the rotation direction.

The TozerDAC X-Ray is a very small cell (12 mm diameter, 11 mm height) with a compact design that makes use of both the turnbuckle principal and the conical Boehler-Almax design anvils. It can be easily accommodated in any X-ray instrument and used in conjunction with cryogenic jet coolers for use at low temperatures.

TozerDAC X-Ray

Most diamond anvil cells use a sliding arrangement, either of a piston in cylinder or of a plate along guide rods, to allow the anvils to move towards each other. In the Boehler-Almax PlateDAC,  two steel plates accommodating the anvils are set at a fixed distance apart, and then the plates are bend to bring the anvils into contact.

The plates are held apart by pin screws toward the edge, used also for tilt adjustment, while the clamping screws, toward the centre, force the anvils together. For an easy operation the two plates are elastically deflected with the use of a driving gearbox.

The MegabarDAC uses also the principle of elastically deflected top plate in the center to apply pressure to the sample. Contrarily to the PlateDAC, in this design, the DAC components are contained into a rigid shallow cylinder where the top anvil plate has a very tight fit with the cylinder. The pressure is applied using a tight fit lid via 3 precision high pressure screws. This DAC offer maximum stability for the diamond anvils even under extreme conditions of pressure and is capable of reaching pressures above 300 GPa.  

Boehler-Almax PlateDAC

MegabarDAC