a glance of YBJ
International Cosmic Ray Observatory is located at 90¡ã26'E and 30¡ã13'N
in Yangbajing (YBJ) valley of Tibetan highland, near the cross point of
Qinghai ¨C Tibet and China - Nepal highways, and the Qinghai - Tibet
railway (to be completed in 5 years), about 90 km away from the city of
Lhasa. YBJ's wide and flat topography, convenient traffic, scarce heavy
snow, rich geothermal power source, about 4,000 residents and many
neighboring institutions & services, make it the best site of high
altitude observatory in the world.
YBJ Observatory was founded in 1990. It has
hosted the Tibet AS¦Ã Experiment (Sino-Japanese Cooperation) ever since.
After 6 years¡¯ preparation, the ARGO -YBJ Project (Sino-Italian
Cooperation) started its detector installation in 2000. Both of them aim
at the research of the origin of high energy cosmic rays, the GRB physics
in high energy, the correlation between the movement of the Cosmic ray sun
shadow and the solar/interplanetary magnetic field and solar activity,
etc. through the observation of air showers (AS) by AS array
semi-full sky and continuous observation technique. Taking advantage of the YBJ high altitude, by increasing the density of scintillation
detector, the AS¦Ã Array has successfully observed ¦Ã rays from Crab
Nebula and Mrk 501 (during its flaring period in 1997); by developing the
traditional sampling AS array as a "carpet", the ARGO-YBJ full
coverage array is intended for exploring the approximately 100 GeV
uncultivated land and measuring the antiproton/proton ratio by cosmic ray
Beside the AS array, neutron monitor and
neutron telescope have been available for solar and hiliosphere study.
Along with the further development of the observatory, the existing
detectors will be upgraded and more new type detectors adopted.