Fall/Winter 2012

Terry Benson knows Drilling at the South Pole

PSL engineer Terry Benson (right) and PSL Technician Darrell Hamilton
with the ARA drill at the South Pole.

Meet the PSL lead engineer on the ARA drill, Terry Benson. He is young and enthusiastic with extensive experience for someone his age when it comes to working with drilling at the South Pole. He worked on IceCube through graduate school and continued to the completion of the project. “When we were finished with IceCube we ended pretty high on the horse. In the beginning of IceCube, we had many problems, but by season 5, 6 and 7 the drill just purred and we had mastered it, but ARA is a different animal,” Terry Benson said, “It is frustrating to go backwards. In solving challenges you realize that there are more challenges.” On the other hand he explains that many aspects to ARA are simpler than IceCube. “The detectors for IceCube all had to be able to withstand pressurization of 10,000 PSI, due to the freeze back of the water. All the waterproofing that was needed with IceCube is also unnecessary with ARA. The drill holes for ARA need to be dry and shallow and the drill itself needs to be light enough for mobility,” he said. 

However, a light and mobile drill has its own set of problems. Although the lack of water usage with ARA makes for fewer requirements on the instrumentation and the connectors, the opposite is true with the drill itself. “Drilling in water is buoyant, but in a dry hole everything is heavier. The hole needs to be 200 meters deep with a six inch diameter. This requires a pretty awesome pump and finding the right pump package that works with the drill head. While the drill goes down the water pumps out, that way there is a dry space, this is unique and has not been done before,” he said “And this drill has to be mobile enough to travel over a surface area of 100 square kilometers in comparison to the 1 square kilometer for IceCube. The first drill for ARA was built of spare parts from the IceCube drill. We needed to get a drill together that could meet the requirements of the initial grant. Monies then were reallocated and reprioritized by the science community to make improvements to the drill for this drilling season.” As Terry Benson tries to solve the engineering challenges that arise, a technician is working on testing the equipment. 


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