String 40 was installed successfully on 18 January. This is the fifth string of the season. String 50 was installed successfully on 22 January. This is the sixth string of the season. Hole 7, location 59 was started 19 January at 9:15 am local time. The rate at which holes are drilled has improved since the beginning of the season. Time to drill a hole this week averaged just over 48 hours from the start of firn drilling to the time the weight stack is removed. This was accomplished on both hole five and six. Remaining time between holes is used to relocate hoses, cables and equipment as well as to give the drill crew much needed rest.
During the last week almost the entire IceCube crew took part in the transportation of around 300 DOMs from the DOM field in front of the Temporary Counting House to the Science Lab in the Elevated Station. These DOMs will be stored inside the station over the winter and will be deployed in the next season. The DOM field has been cleaned from packing material and pallets.
DOM Testing was completed a couple of weeks ago, a small number of 16 DOMs failed the tests or were sorted out during deployment. The failure types include broken connectors, crazing gel, communication problems and high noise rates. 9 DOMs have been sent back to the north and will be reworked or integrated into test systems. The remaining part of these failed DOMs are stored at the South Pole and will be retested and inspected prior to deployment in the next season. Most of the failures are only marginal and can probably be waived after retesting and analysis.
DAQ has collected data from multiple strings numerous times. Four releases of the DAQ have been created, tested on SPTS and subsequently deployed to and run on SPS. A script has been written which has been able to start and stop multi-string runs, performing the correct operations on DOM Hubs, String Processors, event builder and database nodes. This streamlines the operation of the DAQ substantially.
All new Icetop tanks are filled and freezing. Preparations are being made for closing the tanks in early February. Perlite has been delivered to all stations. Eight stations have been partially backfilled. Four stations are still open trenches and will be filled as in-ice string deployment and commissioning finishes.