Wotan: a drill for ice cube

The Antarctic Muon and Neutrino Detection Array (AMANDA) project initially required placing 10-inch spheres in holes 1000m deep at the South Pole. Drilling began during the '93-'94 field season using a hot-water drill because it was the best method capable of drilling holes that were plumb within 0.1 degrees. This type of drill is also modular allowing for expansion to provide more heat if necessary without constructing an entirely new drill. Discovery of bubbles in the ice at 1000m required expansion of drilling capability to drill holes 2000m deep to accommodate 13-inch spheres. We did this by adding more heating and pumping capacity and a larger hose. The successful AMANDA drilling experiences and the analysis of the data returned from the AMANDA spheres has led to the IceCube project proposal. This project will require drilling 80~60-cm diameter holes to 2400m. This paper describes the design of a production hot-water drill called Wotan that is capable of drilling 16 such holes per drilling season.