In the spirit of challenging the frontier issues in mega-science, equipped with current experimental facilities,and basing on existing research condition, we proposed the construction of the magnificent science and technology infrastructure —— the Large High Altitude Air Shower Observatory (LHAASO), oriented to the study and observation of cosmic rays, at Yangbajing, Tibet.
The YBJ International Cosmic Ray Observatory is superior in high altitude, logistical support, and world standard experiment. In LHAASO project, the effective area of detectors will be largely expanded, multiple detection methods will be adopted, thus comprehensive and precise observation will be achieved. And this high altitude cosmic ray research centre at Yangbajing should finally be internationally advanced in gamma ray all-sky survey with high sensitivity and wide spectrum, which would shock the world in unlocking one of the 11 significant frontier scientific puzzles in the new century —— the origin of cosmic rays.
The central scientific goal of LHAASO project is to explore for the origin of high energy cosmic rays, and the evolution of the universe and high energy celestial bodies, and to push forward the frontier of new physics. Statistical samples of various gamma ray sources would be accumulated through all-skyγray source survey and precise measurement of gamma ray energy spectra. By probing/digging into the radiation system, we could find the acceleration source of high energy particles, and measure mono-component cosmic ray energy spectra, thus identify the position of “keen”. Thereby, seamless connection between direct measurement of spatial cosmic ray and the measurement of ground air shower will be realized, and frontier topics of new physics, such as constant and consistent measurement of cosmic ray energy, exploiting dark matter, etc. will be fulfilled.
For these scientific purposes, the LHAASO detector is planned to be established in two phases, consisting three parts: the 1 km2 complex array (LHAASO-KM2A), including 5100 scintillation detectors and 40 km2 distributedμdetectors, 24 air fluorescence/Cerenkov detectors (LHAASO-WFCTA) and 100 m2 burst detectors array (LHAASO-SCDA), and 90 km2 water Cerenkov detector (LHAASO-WCDA). In the second phase, advanced detection technology will be introduced through international cooperation, such as full coverage track detection technology, and two MAGIC-like telescopes, etc, so that we can improve the spatial resolution and lower the threshold energy. The first stage is expected to close within 5 years, with construction cost about 850 million RMB. The second stage would be completed in 6 to 7 years, or an even shorter period, depending on the international cooperation progress, and about 200 million RMB worth foreign investment is planned to be introduced.
The LHAASO project will urge the formation of the international high altitude cosmic ray research centre with multi-country cooperation; will serve as an open and comprehensive scientific research platform with competitive forces worldwide and unique characteristics to itself; and will excellently complement to the current three international cosmic ray research centres. Meanwhile, LHAASO project can also be used as a natural experimental base for various modes of interdisciplinary studies among many frontier sciences, such as atmospheric science, meteorology, space environment, and environmental biology, etc., thus would make huge contribution to the development of related science and technology in China.