BARS apparatus

Lore & Background

The BARS apparatus was developed by scientists at the Institute of Geology and Geophysics of the Siberian Branch of the Academy of Sciences of the USSR. Its design centers on a ceramic cylindrical reaction cell of about 2 cm³, placed into a cubic-shaped pressure-transmitting material pressed by cemented carbide elements. The outer octahedral cavity is pressed by eight steel sectors, and the entire assembly is locked in a disc-type barrel about 1 meter in diameter filled with oil, which pressurizes upon heating.

Reader's Guide

The BARS apparatus represents a significant advancement in high-pressure high-temperature technology, enabling the growth of synthetic diamonds and boron nitride under controlled conditions. Its design allows for pressures of 10 GPa and temperatures of 2,500 °C, with a claimed energy consumption between 1.5 and 2 kWh. The device can grow type Ib (yellow, nitrogen-rich) diamond crystals of 5 to 6 carats in less than 100 hours, with growth rates reaching about 20 mg/h. Its compact exterior size (2.2 x 1.0 x 1.2 meters) and weight of 2.8 tonnes made it a practical tool for mineral synthesis, contributing to the field of materials science and industrial diamond production.

Did You Know?

• The BARS apparatus can achieve pressures of 8–9 GPa (79,000–89,000 atm) and temperatures of 2,500 °C.
• It was developed in the 1970s, with first models operational by the early 1980s, by scientists from the Institute of Geology and Geophysics of the Siberian Branch of the Academy of Sciences of the USSR.
• The device typically grows 1 to 2 carat diamond crystals, requiring longer growth times.
• The exterior size of the BARS apparatus is 2.2 x 1.0 x 1.2 meters and it weighs 2.8 tonnes.