First Year Performance Paper - Section 6
6 Coincidences of String-21 with AMANDA and SPASE
Coincidences with two existing nearby detectors allow further exploration of the response of the IceCube string. The center of AMANDA is 328 m from String-21, and most AMANDA modules are between 1500 and 2000 m deep, as shown in Fig. 28. The center of SPASE is 248 m from the top of String-21, so trajectories through SPASE and String-21 have zenith angles between 5° and 10°.
When these data were taken, neither AMANDA nor SPASE was directly connected to IceCube. As a consequence, coincidences with these detectors were found using the event times from their independent GPS clocks. In the January 2006, the SPASE, AMANDA, and IceCube triggers were connected to permit coincident triggering, and a system for synchronizing the reference times of the three detectors was installed. The detectors will be integrated further in coming years.