1. IceCube simulation with PPC Dmitry Chirkin, UW Madison, 2010 effective scattering coefficient (from Ryan Bay)

2. Direct photon tracking with PPC simulating flasher/standard candle photons same code for muon/cascade simulation using Henyey-Greenstein scattering function with =0.8 using tabulated (in 10 m depth slices) layered ice structure employing 6-parameter ice model to extrapolate in wavelength transparent folding of acceptance and efficiencies precise tracking through layers of ice, no interpolation needed much faster than photonics for E -2 nugen and unweighted CORSIKA:  1000 corsika files (4 sec each) in 24.5 hours  2500 E -2 nugen files in 24.5 hours IC-40 i.e., 10000 E -2 nugen files in ~3-4 days on 6-GPU cudatest

3. Photon Propagation Code: PPC There are 5 versions of the ppc: original c++ "fast" c++ in Assembly for CUDA GPU icetray module All versions verified to produce identical results Also compares well with Tareq’s i3mcml (Mary Murphy’s results) http://icecube.wisc.edu/~dima/work/WISC/ppc/

4. Ice Fitting with PPC It became obvious that the AHA ice parameterization is inaccurate in explaining the IceCube data (flasher, standard candles, muon background, atmospheric neutrino, more?) and a new direct fitting procedure was implemented:  For each set of ice parameters (scattering and absorption at ~100 depths (10- meter slices in depth) the detector response was simulated to 60 different flasher events (on string 63). This response was compared to the data with a likelihood function, which took into account both statistical and 10% belt of systematic errors.  The minimum found with AHA as the initial approximation resulted in SPICE (South Pole Ice) model  The minimum found with bulk ice as the initial approximation but combined with the dust logger data to extrapolate in x and y for positions other than that of string 63, and in depth above and below the detector, resulted in SPICE 2 (South Pole Ice, second iteration) model  More iterations may be possible to take into account other sources of data

5. SPICE verification with CORSIKA by Anne Schukraft

6. Already much better agreement than with AHA! Some disagreement remains, more work is needed

7. SPICE simulation of  by Sean Grullon

8. At the horizon: no need for exotic neutrino interaction ideas

9. Summary 1.PPC is a direct photon propagation tool.  extensively verified  uncompromising precision of ice description  no interpolation  uses full xy map of ice properties  reached the production level of performance 2.SPICE 2 (South Pole ICE) model has been  fitted to IceCube flasher data collected on string 63 in 2008  demonstrated remarkable correlation with the dust logger data  therefore was extended to incorporate these data  use of flasher timing information is possible (under investigation) 3.Very good agreement is demonstrated with  background muon simulation  OM occupancies, COGz, Nch.  time residual slope vs. depth  neutrino simulation  Better agreement than AHA in COGz, Nch, energy estimators  Good agreement in COGz at the horizon