Two strings were installed in the Antarctic ice this week making three new cables added to the IceCube array prior to the Christmas break. Strings 67 and 66 were installed with the help of the deployment and drilling personnel. The first surface to DOM cable for the week, number 67, was placed at a final depth of 2449.47 meters approximately 12 hours after the installation activities began. The second string, number 66, took a little over 17 hours to place at its final depth of 2450 meters and involved the replacement of the deployment reel's (TU-20) brake prior to completion of the installation.
By Dec. 23rd, a total of 6 Surface Cables have been pulled into the ICL. One cable did receive a knick in the insulation as a result from being pulled too fast and scraping the entry of a culvert pipe. The culvert pipe received further grinding and the edge protected by a soft material for future installations. Cable protectors in the cable tray enable only about three cables to be pulled at one time.
South Pole Acoustic Test Setup
The South Pole Acoustic Test Setup (SPATS) is planned for deployment in the upper 400m of holes 78, 48 and 47 (respectively the 8th, 9th and 11th hole of this season). The 3 acoustic strings consist of 7 stages each and each stage contains a transmitter and a sensor module. Detector testing and DAQ chain verification is ongoing, no major problems have been encountered up to this point.
DOM Testing
DOM testing proceeds for DOMs in order of scheduled deployment. DOM testing for string 73 is complete and the DOM-buffer is in place in case DOMs need to be rushed to the drill-camp. The sun has been heating the test stands causing a temperature difference between DOMs under test. Wrapping the test stand with a layer of cardboard reduces this difference. A tent-like structure might be a future solution.The water transport tank was mounted on the sled and is ready for filling. The RO filter in the PHS is in operation and is producing water acceptable for IceTop tank filling.
Six surface cables are installed from the IceTop stations to the Ice Cube Lab. Power and communications are connected in the ICL. Half of the connections are complete from the Surface Junction Box to the tanks. Connections in the ICL to the DOM hubs will be completed soon so that IceTop DOM testing can be completed. A successful DOM communications test is a prerequisite for tank filling.
The images in the 2006 South Pole Greeting Card below were taken by Vladimir Papitashvili in 1956.
