|
|
|
News and Events |
||||||||||||||||||||||
|
||||||||||||||||||||||
|
Celebrating IceCube In March 2008 Berkeley Lab scientists and engineers met to celebrate the completion of 5,693 “mainboards” that are key components of the unique IceCube observatory.
IceCube has very successful third season (2006-2007) at the South Pole with the deployment of thirteen additional strings. During a highly productive season, IceCube scientists and engineers successfully positioned 13 strings of optical sensors deep in the polar ice. Each string carries 60 of the digital optical modules (DOMs), which capture the light emitted in the ice by the products of neutrino collisions. This year's efforts more than doubled the number of installed DOMs to a total of 1,320, roughly one-fourth of the 4,800 sensors that will ultimately make up the IceCube Neutrino Observatory when it is completed in 2011. The lowest DOM on a string resides 2500 m below the surface of the ice (and about 300 m above bedrock). A special purpose five-megawatt hot-water drill is used to melt ice and form a column of water 60 cm in diameter to a depth 2500 m. The DOMs are attached to the electrical cable one by one until all 60 are in place. Then the entire string is lowered to the final depth and the water column refreezes. Once the water freezes, neither the string nor any modules can ever be retrieved. Located at the top of each string are two tanks of ice, each containing two DOMs. These form the surface air-shower array, IceTop. During the first season (2004-2005) one string was deployed, which was followed by eight strings the next season. The 13 strings put in place this season show that IceCube is on track to reach its deployment goal of 16 strings per season. Another major accomplishment of the season was the construction of the new IceCube Lab, which houses the surface electronics and computers that form the data acquisition system. This system collects the information from the DOMs, sorts and analyzes it to determine the detection of cosmic rays and neutrinos. A small percentage of the data will be transmitted via satellite to North America, while the rest is written on magnetic tape at the Pole and brought north when regular flights to the South Pole resume the following October. Even though the last of the deployed strings was still "freezing in" at the end of February, by March, 2007 cosmic ray events involving 20 of the 22 strings have been observed. Here is one example:
__________________________________________________________
IceCube 2005/6 Season In the Nov. 2005 to Feb. 2006 season, IceCube successfully deployed 8 strings of InIce detectors, containing 540 DOMs. In addition, another 24 IceTop ice tanks, containing another 48 DOMs were deployed on the surface. About 99% of the DOMs are operating as designed, an outstanding record.
 LBNL played a major role in this years construction season. Nine LBNL researchers traveled south to the Pole to participate in the deployment and testing: Keith Beattie (Computational Research) Bill Edwards (Engineering), David Hayes (Nuclear Science Division), Arthur Jones (Engineering), Spencer Klein (NSD), Chuck McParland (Computational Research), Jerry Przybylski (Physics) and Mike Solarz (NSD guest), and consultant John Jacobsen (Physics). Data from the 9 string array is already being analyzed. This photo shows one of the DOMs being deployed.
Here is the DOM being lowered into the hole:
The following animation represents a high multiplicity descending muon event:
This animation shows an IceTop-InIce coincident event:
Following is an event triggered by our 'Standard Candle' laser, roughly simulating a
|
||||||||||||||||||||||
