PandaX (Particle and Astrophysical Xenon) experiment lies 7,874 feet undergroundecased in marble in the heart of a mountain in China's Sichuan province, and will be up and running this year. This experiment will run alongside the XENON project in Italy and the Large Undderground Xenon (LUX) efforts in South Dakota to detect dark matter particles.
The project is located in the Jin-Ping underground Laboratory (CJPL)
and will look for particles emitted when the suspected major components of dark matter, weakly interacting massive particles (WIMPS), collide with the nuclei of "normal" atoms in a tank of liquid xenon. Current theories on dark matter implicate that if a WIMP were to bump directly into a nucleus of ordinary matter, the reaction may cause the emission of other particles to create visible evidence. These interactions, if they exist at all, would be incredibly rare, IEEE reported
Comparing the two signals sent from these emitting photons (detectable by a light sensor) and electrons will allow them to determine exactly where the collision occurred. The walls of the tank will emit some radiation, making only collisions in the center of the tank valid.
Why look for WIMPs under a mountain in China? “I think that one should go to the place where one can do the best experiments,” collaborating researcher Wolfgang Lorenzon, a physics professor at the University of Michigan, in Ann Arbor told IEEE. “The big advantage is that PandaX is much cheaper and doesn’t need as much shielding material,” Lorenzon said.
Dark matter is thought to make up more than 80 percent of all matter in the universe and could provide large amounts of information about the working of different galaxies if discovered. This mysterious material has been hypothesized to explain why galaxies have a greater gravitational effect than visible matter can explain.
PandaX, the deepest of the three experiments, is kept underground to stay shielded from other cosmic radiation that could produce mixed signals, reported Space.com
Lorenzon explained that shielding from these possible mistaken WIMP signals is crucial to their experiment. China’s new underground lab is the deepest in the world, meaning it’s well protected from cosmic radiation. The marble rock surrounding the lab is devoid of radioactive materials, further lessening the possibility of receiving false signals.
Ji Xiangdong is the principal investigator of the project and the director of the Institute of Nuclear and Particle Physics at Shanghai Jiao Tong. He describes PandaX as unique because it is designed to grow rapidly. If this project produced results, phase two will have twice the amount of xenon allowing for a better chance to see real results.
The project is competitive, with the European experiment on schedule to double in size in the next few years.
“I’m excited about seeing China developing a fundamental physics program,” Richard Gaitskell, a physics professor at Brown University and a spokesperson for LUX told IEE. “What we have to wait and see [about] is the degree to which the experiment can come up to speed on multiple fronts: cryogenics, shielding, internal radioactivity, and so on.”