Observatory searches for gamma rays

A giant observatory in Sichuan province-designed to detect high-energy gamma rays with the utmost sensitivity and accuracy-launched its first set of detectors on Friday, complementing concerted global efforts to decode the origin of cosmic rays.

Set high on Haizi Mountain, the 136-hectare Large High Altitude Air Shower Observatory will consist of more than 6,300 detectors, an array of 12 Cherenkov telescopes and three water ponds containing 3,000 detecting units, according to the Chinese Academy of Sciences.

As its initial operation unfolds, about one-fourth of the full-scale detector and telescope arrays-which were completed in February-will be deployed to begin intercepting gamma rays and collecting data, while the remaining construction is expected to conclude in 2021, according to Cao Zhen, the observatory's chief scientist and a researcher with the Institute of High Energy Physics at the academy.

One highlight of the latest installation is the 2.25-hectare water pond with a 900-unit Cherenkov Detector Array, Cao said.

"The sky-surveying sensitivity of this water pond has surpassed the most advanced installation in this field in other countries by 30 percent."

As the construction is expected to wrap up in two years, the whole set of three water ponds will be able to scan over 60 percent of the sky each day, unaffected by the light of the sun, moon, stars or weather changes, thus ensuring round-the-clock, comprehensive observations, the academy said.