After setting up and filling 14 IceTop stations, we are almost done with the season. Here are some numbers:
14 IceTop stations (there are 20 IceCube holes planned for this year, but not all of them get IceTop stations)
28 tanks, each with a freeze control unit and contactor to remove dissolved gases
600 gallons of water in each tank, for a total of 16,000 gallons
2 digital optical modules for each tank, for a grand total of 56 DOMs. At this point, we are cleaning up a few loose ends, preparing the tanks for the next two months as the water freezes from the top down. Even thought it is -25 degrees Celsius, it takes about 53 days for the ice to freeze inside the tank, because once the top layer freezes, the ice layer insulates the water below and slows down the freezing process.
I leave Friday along with the IceTop team James Roth and Chris Elliott, and we leave behind a new arrival, Fabian Kislat, who will monitor the tanks as they freeze and fix any problems that arise.
Chris Elliott, John Salvato, and I celebrate the filling of the final IceTop tank of the season, standing in front of Tank 43B.
James Roth and Fabian Kislat celebrate the filling of the final IceTop tank of the season from inside the Purple Palace, headquarters of the IceTop installation.
In contrast, the IceCube deployment team will continue to work hard through January. The plan for IceCube is to install 20 strings, each with 60 DOMs for a total of 1200 DOMs! The IceCube process takes longer to install each string, because it takes at least a day to drill the hole to a depth of 2450 meters, and then another day to run tests and place in a string of DOMs.
After the IceCube team finally clears out by February, they will leave behind two winter-overs: Emanuel Jacobi and Ralf Auer, who will monitor the equipment and keep an eye on things for the cold and dark winter, until the 2010-2011 season starts up in October next year.
In the preceding four seasons, the IceCube team had installed 59 strings, and after this year's 20 strings, that leaves only 7 remaining for next year to bring it up to the final total of 86 strings.