Building The Askaryan Radio Array At The South Pole

This season while living and working at the Amundsen-Scott South Pole Station, Antarctica, I’ve had the opportunity to meet and in some cases work with a few incredibly talented science teams taking part in ground breaking research. One such team was the ARA Team to construct the Askaryan Radio Array – A large-scale radio Cherenkov neutrino detector at the South Pole. Run by Principle Investigator Albrecht Karle, the ARA team consisted of experts in multiple fields. Drill team members Jim Haugen, James Roth, Terry Benson, Dave Pernic, Rob Young, Darrel Hailton and Thomas Mueres worked tirelessly to assemble and test the drill rig, and to drill ultra-precise holes deep into the ice. Deployment and instrumentation team members Chih-ching Chen, Jonathan Davies, Michael DuVernois, Yael Hagar Landsman, Christian Miki, Jiwoo Nam, Ken Ratzlaff, Michael Richman, and Ben Rotter successfully deployed the full suite of instrumentation deep into the ice, and linked it back to the Ice Cube Laboratory via fiber optic cable entrenched under the ice. Additionally, joining the team for a portion of the season was teacher Elizabeth Ratliff, who was here in conjunction with the PolarTrek program.

An overview of the project, from the USAP Science Planning Summary:

Dr. Karle and his international collaborators will probe the nature and cosmic evolution of the accelerators of the highest-energy cosmic rays by observing ultra-high-energy neutrinos produced when cosmic rays interact with the microwave background. At these very high energies, neutrinos can be detected in dense, radio-frequency-transparent media, such as ice, by the Askaryan effect. Its origin is an excess negative charge that builds up when electrons are swept out along a shower front advancing relativistically through the ice. The thickness )estimated to be almost two miles) and exceptional radio-frequency clarity makes the south pole ice cap an ideal place to study ultra high energy neutrinos. This project will develop and deploy a limited number of radio detector stations which will provide the basis for development of a much larger array. The work builds upon past and current neutrino observations including the IceCube and AMANDA Cherenkov observatories and the RICE and ANITA radio Askaryan telescopes in Antarctica as well as the Pierre Auger cosmic ray observatory in western Argentina.

Throughout the first 2/3 of the season, I was privileged to be invited out to the field with the ARA team, to help out with a variety of levels of drill rig construction and testing of the drill rig, actual drilling deep into the polar ice sheet, and finally deployment of the first three ARA field instrumentation stations. Working with the team in the field was very hands on, precise, difficult, and rewarding work. Seeing the drill rig take shape, and then witnessing it drill actual holes deep into the ice was an extremely satisfying experience, as was working out on the polar ice with a great team.

A few photos and commentary from my season working with the ARA team…

We started the season by hauling all of the drill rig components out to a space in front of the IceCube laboratory. This was the main worksite for putting everything together. In addition to the drill rig components, we also had a number of large shipping containers which served as workshops and supply sheds.

Driving in a winterized van from the south pole station out to the IceCube Laboratory (ICL)

Morning briefing, before starting work

Showing up in the mornings at the beginning of the season, here’s the rig components starting to come together

One of the emergency stop switches I installed – drilling with hot water in the middle of nowhere with a jet fuel-powered sled is dangerous – and the ability to shut it down instantly is critical.

Looking from the step at the mouth of the water tank down towards the snow melter, heaters, and hose reel.

Terry Benson double checking the valve configuration to feed hot water into the drill head

Me, fabricating a metal gutter, to catch water drips coming out of the main tank. Any liquid water that spills freezes almost immediately, so funneling it away from our work area and into a steel drum, and then into the ice, was critical.

And my gutter, installed. I also routed most of the electronics cables between the heater/hose reel sled and the tank sled.

The drill sled, almost complete, ready to be dragged out to the first drill site.

The drill team, in front of the newly assembled hose reel

After all of our equipment was towed out to the drill site, we got aroudn on snowmobiles – either on the machine itself, or riding a sled dragged behind. A very fun way to get around – although wind whipping through while zipping along the snow creates an incredible wind chill.

The ARA3 Drill Site. In this picture, you can see the fully assembled and working drill rig, as well as our power generator, and field workshop.

Inside the workshop we stored drill heads, supplies, food, medical equipment, etc. There was also a heater, microwave, and coffee maker.

As drilling gets started for the day, the team checks the status and fine-tunes the process at the Drill Information Center, built by James Roth.

The drill head, being guided down the fern hole.

Securing the drill head to the drill hose, and getting all of the water and power connections working.

As drilling proceeds, the team has various tasks, including keeping an eye on the reel progress, and maintaining rubber spacers embedded in the hose assembly.

And finally, a successfully drilled hole. In addition to these deep holes, sensors are also deployed in shallow pits on the surface.

After drilling is complete, the deployment team gets to work installing electronics and sensors into the ice. Here’s deployment expert Ben Rotter with the Pisten Bully that transports the deployment team.

The beginning of the ARA2 site. Eventually this box gets filled with data acquisition and relay electronics and buried in the ice.

The electronics box sits at the center of each site, and has a web of data and power cables extending out to each sensor array. Here’s the team burying the cabling for each sensor.

One of the shallow sensors, before being covered up.

Deep trenches allow the cables to be buried deep to protect them from any machinery driving overhead.

And finally, the ARA team at the south pole.

Thanks very much to the entire ARA team for generously allowing me to work with them throughout the season. Hopefully we’ll work together again sometime soon.