The Jinping Underground Labatory in southwestern China's Sichuan province is making Western countries nervous, according to German newspaper Suddeutsche Zeitung.
First put into service in late 2010, the Jinping Underground Labatory is China's first deep underground lab which provides an experimental platform for cutting-edge underground scientific research.
Inping is the deepest underground lab in the world with vertical rock coverage of 2,400 meters. Cosmic rays are said to be 200 times weaker in the lab compared to the Laboratori Nazionali del Gran Sasso in Italy.
Jinping underground lab may give China the lead in research: report|WCT
PandaX
PandaX is designed to build and operate a ton-scale liquid xenon experiment to detect the so far elusive dark matter in the Universe. The PandaX experiment will use a two-phase (liquid and gas) xenon position-sensitive time projection chamber detector. The program will evolve in two stages, initially probing the low-mass regime (<10 GeV) with a nuclear- recoil energy threshold of about 5 keV and ultimately employing a ton-scale detector to probe the higher-mass regime (10–1,000 GeV), reaching a sensitivity down to 10^-47 cm^2 for spin-independent WIMP-nucleon cross section.
Design of the PandaX stage-1a TPC integrated with the inner vessel
CJPL
The PandaX experiment is designed as a next generation liquid xenon experiment using the two-phase technique. It is
located at the China Jin-Ping underground Laboratory (CJPL), which is in the middle of a 18-km tunnel under 2400 meters of rock overburden, in the Sichuan province of south-west China. As one of the deepest underground labs in the world, the CJPL has an extremely low flux of muon rate of less than 20/m^2/100-day, which is about two orders of magnitude lower than the flux at the Gran Sasso underground laboratory (LNGS) in Italy. The low muon rate and the resulting background makes the lab ideal for a sensitive dark matter detection.
Located in the Sichuan province of China, CJPL is one of the deepest underground labs in the world
Scientists across China and the United States collaborating on the PandaX search for dark matter from an underground lab in southwestern China report results from the first stage of the experiment in a new study published in the Beijing-based journal SCIENCE CHINA Physics, Mechanics and Astronomy.
PandaX is the first dark matter experiment in China that deploys more than one hundred kilograms of xenon as a detector; the project is designed to monitor potential collisions between xenon nucleons and weakly interactive massive particles, hypothesized candidates for dark matter.
In the new study, scientists explain, "Dark matter is a leading candidate to explain gravitational effects observed in galactic rotational curves, galaxy clusters, and large scale structure formation."
"Weakly interacting massive particles (WIMPs), a particular class of dark matter candidates, are interesting in particle physics and can be studied in colliders [and in] indirect and direct detection experiments."
If confirmed, dark matter particles would extend understanding of the fundamental building blocks of nature beyond the Standard Model of particle physics, and would provide support for theories on supersymmetry and extra dimensions of space-time.
"Direct positive detection of WIMPs using ultra-low background detectors in deep underground laboratories would provide convincing evidence of dark matter in our solar system and allow the probing of fundamental properties of WIMPs," they add in the new study.
Direct detection experiments using different technologies have produced many interesting results, but not universally confirmed evidence of weakly interacting massive particles. These results have produced much excitement across the global scientific community and call for further examination of WIMP signals through other experiments.
"In recent years, new techniques using noble liquids (xenon, argon) have shown exceptional potential due to the capability of background suppression and discrimination, and scalability to large target masses," state the PandaX collaborators.
"The XENON10/100 and LUX experiments using the dual-phase technique have improved WIMP detection sensitivity by more than two orders of magnitude in a wide mass range."
China's PandaX experiment, operated at the China Jinping Underground Laboratory, uses the dual-phase xenon technique to search for both low and high mass WIMP dark matter.
The initial success of the PandaX project demonstrates China has joined the global competition at the scientific frontier marking dark matter searches.
Today more than twenty dark matter search experiments are being conducted worldwide. Many dark matter search experiments, such as the DAMA/LIBRA experiment in Italy, the CoGeNT and CDMS experiments in the US, and the German-led CRESST experiment have reported findings that could be interpreted as positive signals of dark matter in recent years.
The PandaX collaboration joins this effort with results from a dark matter search that started in May of 2014.
No dark matter signal was observed in the first PandaX-I run, which places strong constraints on all previously reported dark matter-like signals from other similar types of experiments.
The PandaX experiment to date has collected about 4 million raw events; only about ten thousand events fell into the energy region of interest for dark matter. In the quiet central part of the xenon target only 46 events were observed.
However, the data from these 46 events was consistent with signals marking background radiation, not dark matter.
PandaX stands for Particle and Astrophysical Xenon Detector. The experiment is being conducted by an international team of about 40 scientists, and led by researchers from Shanghai Jiao Tong University.
The goal of the first stage of PandaX experiment is to examine previously reported dark matter-like signals. The scale of the PandaX-I experiment is second only to that of LUX, which is currently the planet's largest dark matter experiment and is located in a South Dakota mine in the US.
To shield the Chinese experiment from cosmic rays, the PandaX detector is located at the China Jinping Underground Laboratory (CJPL), the deepest underground laboratory in the world. CJPL was developed by Tsinghua University and the Yalong River Hydropower Development Company in 2010.
First dark matter results from underground China lab hosting PandaX-I
Congrats to Chinese bros and Tsinghua Uni for creating such a state of the art facility.