University of Wisconsin-Madison Physical Sciences Lab

Enhanced Hot Water Drill

Hot Water drill photo

In 1995, PSL designed and constructed the first hot water drill for the Antarctic Muon and Neutrino Detector Array, the predecessor to IceCube. The drill was used to drill holes in the Antarctic ice two kilometers deep in which the detector arrays were placed. The drill had to be able to withstand external pressure of 3400N/sq cm (5000 pounds per square inch), send and receive signals through 3200 meters of cable, and deviate from straight by no more than 1 meter. To overcome these difficulties, PSL created a modular drill head including a power and telemetry module, a navigation pack module, and a sensor module. The drill works by shooting hot water (about 90° C) out of a nozzle at the end. As the water melts the ice ahead, it cools and then is pumped out of the hole and back into the water heaters to be reheated and reused. Each hole took about three days of nonstop drilling.

As part of the preparation for IceCube and its installation, PSL helped to develop, commission, maintain and improve the enhanced hot water drill to be capable of drilling over 2 kilometers deep in about 1.5 days. PSL constructed and periodically refurbished multiple drill heads during the installation of IceCube.