GeV Observatory in Tibet

[antoniseb]

http://arxiv.org/PS_cache/astro-ph/pdf/0609/0609317.pdf

This is a paper talking about an obersvatory at 4300 meters altitude with 6700 square meters of particle detection surface (so far), which will hopefully start detecting 1 GeV signals or higher from GRBs and other cosmic sources.

So far, it has seen nothing connected to a GRB.

[Blob]

Hum,
i cant seem very much information about the observatory on the net.
(even the location on the official site seems to be wrong).


YBJ Observatory was founded in 1990. It has hosted the Tibet ASγ 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

Read more (http://www.ihep.ac.cn/english/YBJ-E/index.htm)

Read more (http://argo.na.infn.it/)

Latitude: 30.13516° Longitude: 90.52452°

[Blob]

A mysterious surplus of energetic particles called cosmic rays is striking the Earth from the direction of the constellation Cygnus, suggests a controversial new study. If confirmed, the detection of this excess may help scientists figure out what produces these enigmatic high-speed particles.
Cosmic rays are speeding charged particles that appear to hit Earth in roughly equal numbers from all directions. Lower energy cosmic rays are thought to come from the shock waves around supernovae, but the source of the higher energy ones is still a mystery.
When a cosmic ray hits Earth's atmosphere, it produces a burst of charged particles and light. Sensitive detectors on the ground measure either the secondary particles or the light to try to determine the direction from which each cosmic ray came.
However, no one has been able to unequivocally trace cosmic rays to a specific object like the expanding shell of a supernova.
Now, observations have revealed what appears to be a broad area of enhanced cosmic ray activity in the sky. The data comes from the Tibet Air Shower Arrays, which detects the secondary particles produced when cosmic rays or high-energy radiation slams into the atmosphere.

Read more (http://www.newscientistspace.com/article.ns?id=dn10338)

[RussT]

One of the main problems with this is that most of high GeV and almost all of TeV energy Gamma Rays are absorbed before they ever reach the earth.

[Jens]

I was just wondering, but is there anything special in the direction of Cygnus? I was thinking maybe the galactic center, but apparently not.

[antoniseb]

is there anything special in the direction of Cygnus?
There are a few strong discrete x-ray sources, such as Cyg X1 and Cyg X3.

[Blob]

Title: Underground Water Cherenkov Muon Detector Array with the Tibet Air Shower Array for Gamma-Ray Astronomy in the 100 TeV Region
Authors: The Tibet AS Gamma Collaboration: M. Amenomori, et al

We propose to build a large water-Cherenkov-type muon-detector array (Tibet MD array) around the 37,000 m² Tibet air shower array (Tibet AS array) already constructed at 4,300 m above sea level in Tibet, China. Each muon detector is a waterproof concrete pool, 6 m wide x 6 m long x 1.5 m deep in size, equipped with a 20 inch-in-diameter PMT. The Tibet MD array consists of 240 muon detectors set up 2.5 m underground. Its total effective area will be 8,640 m² for muon detection. The Tibet MD array will significantly improve gamma-ray sensitivity of the Tibet AS array in the 100 TeV region (10-1000 TeV) by means of gamma/hadron separation based on counting the number of muons accompanying an air shower. The Tibet AS+MD array will have the sensitivity to gamma rays in the 100 TeV region by an order of magnitude better than any other previous existing detectors in the world.

Read more (http://arxiv.org/PS_cache/astro-ph/pdf/0611/0611030.pdf) (87kb, PDF)

[antoniseb]

I saw that paper. It is pretty cool what is being done there. Amazing how much this improves the signal/noise ratio on the other detector.

[RussT]

Title: Underground Water Cherenkov Muon Detector Array with the Tibet Air Shower Array for Gamma-Ray Astronomy in the 100 TeV Region
Authors: The Tibet AS Gamma Collaboration: M. Amenomori, et al

We propose to build a large water-Cherenkov-type muon-detector array (Tibet MD array) around the 37,000 m² Tibet air shower array (Tibet AS array) already constructed at 4,300 m above sea level in Tibet, China. Each muon detector is a waterproof concrete pool, 6 m wide x 6 m long x 1.5 m deep in size, equipped with a 20 inch-in-diameter PMT. The Tibet MD array consists of 240 muon detectors set up 2.5 m underground. Its total effective area will be 8,640 m² for muon detection. The Tibet MD array will significantly improve gamma-ray sensitivity of the Tibet AS array in the 100 TeV region (10-1000 TeV) by means of gamma/hadron separation based on counting the number of muons accompanying an air shower. The Tibet AS+MD array will have the sensitivity to gamma rays in the 100 TeV region by an order of magnitude better than any other previous existing detectors in the world.

Read more (http://arxiv.org/PS_cache/astro-ph/pdf/0611/0611030.pdf) (87kb, PDF)

:dance: :clap: :D :dance: :clap:

[Bokmakierie]

One of the main problems with this is that most of high GeV and almost all of TeV energy Gamma Rays are absorbed before they ever reach the earth.

The HESS observatory in Namibia gets around this problem by looking at Cerenkov radiation caused by the GEV and TEV gamma ray photons http://www.mpi-hd.mpg.de/hfm/HESS/HESS.html