STRAW: STRings for Absorption length in Water
2019 July 22
Neutrino astronomy uses large volume detectors to search for astrophysical neutrinos and pinpoint their origin. Detectors such as IceCube at the Geographic South Pole, the Gigaton Volume Detector (GVD) in Lake Baikal and KM3NeT in the Mediterranean sea, instrument up to a cubic kilometer of water or ice for measuring Cherenkov radiation created in neutrino-matter interactions. Especially the utilization of the clear water of the deep sea as Cherenkov medium, in the past, has been facing severe difficulties in deploying and maintaining the offshore infrastructure. Ocean Networks Canada (ONC), an initiative of the University of Victoria, has been operating deep sea infrastructure for scientific purposes, off the Canadian coast since years. One of their network nodes, located on the Pacific abyssal plain, off the coast of Vancouver Island - Cascadia Basin - could be an ideal site for a future neutrino telescope. The Strings for Absorption Length in Water (STRAW) were developed at the Technical University of Munich (TUM) in collaboration with ONC and the University of Alberta. Two strings with optical modules have been deployed at Cascadia Basin in order to measure the optical properties of the water and study the feasibility of a larger installation. We will give a brief overview of the STRAW setup and present first results on the absorption length and optical background at Cascadia Basin.