D-DIA

A high-pressure experimental apparatus used in geoscience

Overview

The D-DIA is a type of high-pressure apparatus used primarily in the field of geoscience to simulate the conditions found deep within the Earth. It is a modified version of the multi-anvil press, designed to apply both high pressure and high temperature to a sample, allowing researchers to study the physical and chemical properties of materials under extreme conditions.

Example of a D-DIA assembly

Design and Functionality

The D-DIA apparatus is characterized by its use of a cubic anvil system, which allows for the application of pressure from multiple directions. This design is particularly useful for deforming samples under controlled conditions, making it an invaluable tool for studying rheology and deformation mechanisms in minerals and rocks.

The apparatus typically consists of six anvils arranged in a cubic configuration, with the sample placed at the center. The anvils are driven by hydraulic rams, which can apply pressures up to several gigapascals. The D-DIA is also equipped with a heating system, often using a graphite or tungsten heater, to achieve temperatures exceeding 1000°C.

Applications

The D-DIA is used to investigate a wide range of geological processes, including:

• Mantle convection: By simulating the high-pressure and high-temperature conditions of the Earth's mantle, researchers can study the flow and deformation of mantle materials.
• Seismic anisotropy: The apparatus allows for the examination of how minerals deform under stress, which can help explain the anisotropic properties observed in seismic waves.
• Phase transitions: The D-DIA can be used to study phase transitions in minerals, such as the transformation of olivine to wadsleyite or ringwoodite, which are important for understanding the structure of the Earth's interior.

Diagram of a D-DIA setup

Advantages

The D-DIA offers several advantages over other high-pressure devices:

• Controlled deformation: Unlike traditional multi-anvil presses, the D-DIA allows for precise control over the deformation of the sample, enabling detailed studies of creep and plasticity.
• In situ observation: The design of the D-DIA permits the use of X-ray techniques to observe the sample in real-time during experiments, providing valuable insights into the dynamic processes occurring within the sample.

Limitations

Despite its advantages, the D-DIA has some limitations:

• Pressure range: While the D-DIA can achieve high pressures, it is generally limited to pressures lower than those achievable with diamond anvil cells.
• Sample size: The size of the sample that can be studied is relatively small, which can limit the types of experiments that can be conducted.

X-ray radiograph of a sample under pressure

Related pages

• Multi-anvil press
• Diamond anvil cell
• High-pressure mineral physics