December 8, 2009, South Pole Station –
Progress Report for the week ending 12/05/09
Monday of this past week, six surface cables were pulled into the IceCube Lab (ICL). This is an IceTop milestone each season because we can not install the FCUs into the tanks until we have power from the ICL. Tuesday, the cables were connected in the ICL to Power and Communications for the Freeze Control Units (FCUs), and the Digital Optical Modules (DOMs) were connected to the computer hubs. Twenty-four DOMs passed the system communications test, so we were cleared to fill tanks.
Miles of cables in the ICL! Six new surface cables added. Photo by James Roth
The remaining IceTop tanks arrived from McMurdo and were prepared and installed in the remaining trunk 4 IceTop pits. Arne Van Overloop and Freija Descamps helped us by delivering the remaining Surface Junction Boxes (SJBs) during the night shift. Emanuel Jacobi and Hermann installed the remaining DOMs in the tanks.
Chris and Casey installed FCUs in the first 12 IceTop tank enclosures.
Chris Elliott connects an FCU in the tank enclosure. Photo by Hermann Kolanoski
Wednesday afternoon, we filled our first two IceTop tanks at station 8 ahead of schedule. The fills went like clockwork, but that wouldn’t last. We scheduled another set of tanks to be filled Thursday afternoon, but were haunted by a stubborn frozen fill hose. We thawed the hose overnight in the Purple Palace, and filling resumed Friday morning. By the end of Saturday, we filled 10 IceTop tanks.
Top: The “Water Buffalo” carries filtered water to the fill site. Bottom: First fill of an IceTop tank this season. Photos by Hermann Kolanoski.
We overcame other slight setbacks consisting of high glycol content in the water, communication problems at station 25, a dirty tank at 25B, and a bad contactor assembly at station 15B. A contactor is the device inside each tank that removes dissolved gasses from the water to produce clear ice. This was the first time in the 128 tanks deployed so far that we had to change a contactor after the tank had been filled.
Top: Hermann tests water samples for glycol content. Photo Casey O’Hara. Bottom: James replaces a defective contactor. Photo Chris Elliott
Monday, the remaining eight surface cables will be pulled into the ICL. Filling will continue with station 25 and the rest of the stations as the new surface cables are connected.