The Deep Underground and Ultra-low Radiation Background Facility for Frontier Physics Experiments (DURF), the world’s deepest and largest physics facility was completed and put into use on December 7. (PHOTO: XINHUA)

By WANG Xiaoxia

Some 2.4 km below the earth’s surface, the world’s deepest and largest physics facility was completed and put into use on December 7. 

The Deep Underground and Ultra-low Radiation Background Facility for Frontier Physics Experiments (DURF) is the second phase of China Jinping Underground Laboratory, which is tucked inside the Jinping Mountain in Sichuan province, southwest China. 

The site is ideal for its low cosmic-ray muon flux -- only one-hundred-millionth of that on the earth's surface, which means the facility has far less noise from background radiation than many other underground facilities.  

The DURF is mainly designed for major basic research on physics, and carries out experiments in frontier fields, such as direct detection of dark matter, neutrinoless double beta decay, as well as key nuclide synthesis processes and stellar evolution in the field of nuclear astrophysics. Therefore, it will provide a platform for interdisciplinary research integrating particle physics, nuclear astrophysics and life sciences. 

China Jinping Underground Laboratory consists of two phases. Its first phase was completed and began operation at the end of 2010. With a total volume of about 4000 cubic meters, it housed two experiments to directly detect dark matter: the China Dark Matter Experiment (CDEX) and PandaX. 

The completion of the second phase, namely the DURF, has enlarged the lab’s total room capacity by nearly 80 times to 330,000 cubic meters. Ten research teams from Chinese universities and research institutions, such as Tsinghua University, China Institute of Atomic Energy and Shanghai Jiao Tong University, have been stationed in the DURF to carry out scientific experiments. 

Meanwhile, the DURF was jointly built by Tsinghua University and Yalong River Hydropower Development Company. It is the first time that a large state-owned enterprise supported national basic scientific research.