Mainz 2004 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

T: Teilchenphysik

T 102: Kosmische Strahlung II

T 102.2: Talk

Monday, March 29, 2004, 16:05–16:20, HS III

Time calibration of the AMANDA neutrino telescope — •Elisa Bernardini — DESY-Zeuthen, Platenenallee 6, D-15738 Zeuthen

The reconstruction of particle tracks in the AMANADA detector is based on the photon arrival times at the photomultiplier tubes (PMTs) located in the Antarctic ice sheet. This requires precise knowledge of the delays of the signals from each PMT. Major sources of delays are the signal transit times in the cables (transmitting signals from depth up to about 2 km to the surface) plus an off-set introduced by the use of a fixed threshold to discriminate the signals. Two methods for time calibration are used in AMANDA. In one case each individual PMT is illuminated with signals from a YAG laser at the surface which are diffused in the proximity of the sensors. The recorded signal delays are measured with respect to the laser trigger time (T0s). An independent procedure makes use of the down-going muons recorded by AMANDA. An iterative algorithm is applied, which minimizes the difference between the times recorded by the hit PMTs and the times expected for the best track hypothesis. At each iteration an updated guess for the T0s of each PMT is applied prior to track reconstruction. This talk will illustrate both methods and discuss a comparison of the performance. The time calibration method designed for IceCube will also be introduced.