The IceCube neutrino observatory uses $1\,\mathrm{km}^{3}$ of the natural Antarctic ice near the geographic South Pole as optical detection medium. When charged particles, such as particles produced in neutrino interactions, pass through the ice with relativistic speed, Cherenkov light is emitted. This is detected by IceCube’s optical modules and from all these signals a particle signature is reconstructed.
A new kind of signature can be detected using light emission from luminescence. This detection channel enables searches for exotic particles (states) which do not emit Cherenkov light and currently cannot be probed by neutrino detectors. Luminescence light is induced by highly ionizing particles passing through matter due to excitation of surrounding atoms. This process is highly dependent on the ice structure, impurities, pressure and temperature which demands an in-situ measurement of the detector medium.
For the measurements at IceCube, a $1.7\,\mathrm{km}$ deep hole was used which vertically overlaps with the glacial ice layers found in the IceCube volume over a range of $350\,\mathrm{m}$. The experiment as well as the measurement results are presented. The impact of the results, which enable new kind of searches for new physics with neutrino telescopes, are discussed.