Site Characterization for a Greenland Neutrino Observatory

PI Institute/Department Email
Vieregg, Abigail
U of Chicago, Department of Physics
Award#(s)
ViereggNeutrino
Funding Agency
US\Research/Higher Ed\H-SCfA
Program Manager Funding Agency Email
Crain, Ms. Renee
NSF, Office of Polar Programs
Discipline(s)
Space Physics\Astrophysics
Science Summary

Ultra-high energy (UHE) neutrino astronomy is a rapidly evolving field that sits at the crossroads of particle physics, astronomy, and astrophysics. Neutrinos travel virtually unimpeded through the Universe, making them unique messenger particles for cosmic sources, carrying information about very distant sources that would otherwise be unavailable. Detection of ultra-high energy neutrinos could also reveal the origin of cosmic rays. Current and recent efforts to detect UHE neutrinos (the balloon-borne ANITA experiment, the ARA effort at the South Pole, and ARIANNA on the Ross Ice Shelf) have utilized radio detection techniques, searching for coherent, impulsive radio signals that are emitted as electromagnetic particle cascades are induced by neutrinos interacting with a dielectric such as ice. UHE neutrino detection requires enormous volumes of a naturally-occurring dielectric material that allows radio signals to pass through without significant attenuation. Current experimental efforts monitor enormous volumes of Antarctic ice, whose radio attenuation properties have been directly measured by us and our collaborators at multiple locations in Antarctica (Barrella et al. 2010, Besson et al. 2008, Barwick et al. 2005). ANITA searches for neutrinos interacting within all of the ice that is within its 700 km horizon while the payload is at float altitude, while ARA and ARIANNA both instrument smaller sections of ice directly on (or just below) the surface. If the neutrino detectors that are currently being developed in Antarctica are successful, the natural follow-up experiment would eventually be a similar detector installed in the Northern hemisphere to catalogue the half of the sky that is not visible from Antarctica. Determining the radio attenuation length in ice at Summit Station would be the first step toward site exploration for such a project. The researchers will perform similar measurements at Summit Station in Greenland to those that have been made in Antarctica to determine if the ice there exhibits similar low-loss properties between 200-1200 MHz and measure the radio noise environment at Summit Station. Previous radio measurements of ice properties at Summit Station have been made by geologists (Paden et al. 2005) as a by-product of measurements that characterize the rock interface at the bottom of the ice sheet, and hint at very long attenuation lengths ( > 500 m), rivaling those measured in the Antarctic.

Logistics Summary

Researchers will conduct an experiment to determine the radio attenuation length in ice at Summit Station, to understand if the site exhibits similar low-loss properties as have been observed in Antarctica. Such characteristics are important for the detection of neutrinos, and if the neutrino detectors that are currently being developed in Antarctica are successful, Summit Station may be a suitable location for a similar detector installed in the Northern hemisphere to catalogue the half of the sky that is not visible from Antarctica. During the 2013 field season, a team of four will conduct a site characterization visit to Summit Station to directly measure the radio attenuation length and birefringence of the ice as well as make measurements of the radio noise environment at the site. Previous radio measurements of ice properties at Summit Station have been made by geologists as a by-product of characterization of the rock interface at the bottom of the ice sheet, and hint at very long attenuation lengths ( > 500 m), rivaling those measured in the Antarctic. Researchers will perform a direct measurement of ice properties to compare with measurements made in Antarctica using the same techniques. In June 2015, researchers will return to Summit Station in staggered teams of two to test a phased array of radio antennas in situ. They will establish a day-camp at the DISC borehole to deploy the array in different configurations while transmitting calibration signals from various surface locations. They will temporarily pump drill fluid out of the borehole while doing their tests. Fluid will either be pumped down the borehole after the group is finished or will be retro-ed if CPS determines a cost-effective method. The group will bring their own pump and associated PPE, utilizing containment provided onsite. CPS staff will assist with site set-up and to ensure the pump mates with the provided generator. The group will commute daily to the DISC borehole by foot and will occasionally access the Summit snowmobiles and sleds for days requiring cargo transport.

CPS will provide Air National Guard (ANG) coordination for the field team and cargo; reservations for KISS user days in Kangerlussuaq; user days at Summit Station; FEMCO assistance for site set-up; occasional use of the Summit snow machines and sled; and dedicated allocation of generators, fuel, tents, and communication/safety equipment. NSF will recoup costs associated with this support directly from the PI’s institute. The PIs will make all other arrangements and pay for them through the grant.

Season Field Site Date In Date Out #People
2013
Greenland - Summit
4
2015
Greenland - Summit
4