A calibration study of local ice and optical sensor properties in IceCube

In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

“…Employing the experimental and analysis methods described above, absolute absorption and scattering coefficients and their wavelength scaling have been measured for all instrumented depths as described in detail by Ackermann et al (2006) and Aartsen et al (2013d). The resulting model, called the "South Pole Ice Model" (SPICE), continues to be updated and refined as new aspects of the instrumentation such as the properties of the refrozen drill columns (Chirkin et al, 2021) as well as 260 previously unconsidered features in the ice begin to be modeled. The stratigraphy used as the starting point for this study is shown in Figure 5.…”

“…In both cases a near constant elevation angle of on average 5 • has been fitted. However, this fit is difficult to completely disentangle from effects that may arise as a result of mis-modeling of the layer undulations or the optical properties of the refrozen drill holes (Chirkin et al, 2021). As the resulting improvement in data-simulation agreement was seen to be small, this additional complication is not further considered here.…”

“…The required pre-fits, as well as the final depth evaluation, were performed following the method described in Aartsen et al (2013d) by minimizing the summed LLH comparing the single-LED data set (where all 12 LEDs were flashed one at a time on all in-ice DOMs ) with the full photon propagation simulation of these events taking into account precisely known DOM orientations as measured in Chirkin et al (2021). Fits for individual layers were carried out by only including LEDs situated within the considered (tilt corrected) ice layer into the LLH summation.…”