Reconstruction of the SC with rime Dmitry Chirkin, LBNL

SC event sample cuts distance from COG: poorly reconstructed cascades (e.g., muon events) are pushed far away log likelihood difference of cascade and track reconstructions energy part or llh (Phit-Pnohit)

Cuts and reconstructed energy 100% laser intensity run cascade peak is well selected as seen from both energy and Nch distributions reconstructed energy is log(8.76)/81 cm^2/137000 = 0.52 PeV

Why Nch distribution is so wide

Positional resolution

Positional reconstruction accuracy

All runs: summary % En GeV Rms x y z 100 8.76 519 0.29 15.29 6.11 3.00 8.91 732 0.23 19.81 7.51 2.62 50 8.80 452 0.19 12.80 4.46 25 8.57 335 15.11 6.49 2.59 5 8.10 113 0.16 7.83 3.58 2.46 0.5 7.30 18 0.08 13.53 6.47 3.14

Linearity at high Q

Systematic errors, or charge reweighting Too much emphasis is given the saturated DOMs Remove DOMs above saturation charge from energy llh assign them systematic errors instead of sqrt(N) Poisson still correct charge below and close to saturation Apply the systematic error “belt” to the probability function for 1 d(ln f) error distribution and small systematic errors analytic approximation is possible for 1 df distribution solution is terms of a difference of incomplete gamma functions (still computationally difficult) may need to compute integrals numerically a hybrid approach is possible with systematic errors larger in the intermediate distance region or for charges close to saturation

Laser prepulsing a signal component correlated with the main pulse, some 300 ns before this is larger than the PMT transient time – due to fast decay states or circuit LED light leaking out? While the prepulse is cleaned away by the FeatureExtractor (it’s under 5% of the main pulse), the charge estimate is incorrect

Corrected energy estimate 100%, 50%, 76%, 50%, 25%, 5%, 0.5% 50%, 5%, 0.5%

Laser energy linearity

Laser energy estimate Cascade: 1.37 105 photons/GeV  PMT efficiency / glass transparency at 337 nm at 40% of max at 0.5%: 10^7.3 m^2 / (81 cm^2 * 40%) = 6.16 10^9 photons corresponds to energy of N/137000 = 45 TeV scaling up 200 times: at 100% N = 1.23 10^12; E=9 PeV while N agrees with expectation, E is somewhat smaller  different conversion factor?

Summary Charge is underestimated due to a large emphasis on saturated PMT signal  somewhat correctable by removing oversaturated DOMs from energy llh, still needs better Ellh deficiency in the flux function is somewhat repaired by adding systematic error consideration to the calculation At 5 DOMs away from the laser the charge is proportional to the power percentage setting At 0.5% the laser output is equivalent to a 45 TeV cascade Therefore, at 100% the laser output is equivalent to a cascade of energy 9 PeV, still much less than 100 PeV this is still much better than direct estimate: 1.5 PeV