Water Properties Phone Conference1 Light Generation in KM3 and Photonics Corey Reed (Nikhef) Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference2 Photon Studies Study photon production In different simulation programs KM3 – Antares code MMC+Photonics – Seatray (IceCube) code Explore Time of photon arrival Angle of incidence on PMT Number of photo-electrons Normalization of time residuals Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference3 Photon Studies KM3 program Goulven has done a LOT of work on this program v3r7 : code cleanup, 64bit, FPE trap v3r8 : handle muon stop, handle more particles, more cleanup v3r9 : allow hits from delta electrons, consistent shower generation in GEN and KM3MC v4r0 : implement wavelength dependency (i.e. dispersion) Of photon velocity, Cherenkov angle, # photons v4r1 : fix bugs introduced in v4r0, use geasim reference velocity of light Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference4 Photon Studies Digestible summary: v3r7 : code cleanup v3r8 : more particles possible v3r9 : better low energy d and showers v4r0 : wavelength dependent code v4r1 : fix bugs of v4r0 Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference5 Photon Studies With all MC studies here: Used the Antares detector geometry Never applied weights To allow easy interpretation of error bars No trigger! No reconstruction! Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference6 KM3 Studies Used “lowe” numu files produced by Goulven Runs 88_1 to 88_5 Taken at MCEW level true MC info Up-going nu's Energy : (10^1, 10^7) GeV Same events in each KM3 version! $ANTHPSS/user/guillard/km3BugsAndDisp/MCEW/km3updates.MCEW.numu.lowe.tar.gz Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference7 KM3 Studies First look... Compare time residuals among KM3 versions Overall time residuals Integrate over muon – OM distance, orientation Sum direct + scattered Easier to compare with Photonics (later) Separate photons from tracks vs. showers Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference8 KM3 Studies Time residuals! For photons from muon Compare to true mu Direct + scattered Not normalized Used: Nphase = 1.35 For Chkv angle Ngroup = 1.38 For light velocity Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference9 KM3 Studies Time residuals! For photons from muon All version 3's similar Maybe some bug in v3r7 leads to this? Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference10 KM3 Studies Time residuals! For photons from muon v4r0 looks ok, but peak not at 0 What average Ngroup? 470nm, Ngroup=1.38 not the most probable in this MC? Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference11 KM3 Studies Time residuals! For photons from muon v4r1 does not look ok. Peak also not at 0? Are the direct photons missing? To be checked Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference12 KM3 Studies Time residuals! For photons from showers Direct + scattered Calculated w.r.t. Chkv assumption Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference13 KM3 Studies Time residuals! For photons from showers v3r* looks ok v4r* looks ok (maybe), but what Ngroup used? Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference14 KM3 Studies In depth look... Separate muon – OM distance, orientation Compare with expected photon time distribution dN g /dt : shape and normalization Orientations: m “West”: looking at passing muon g OM m “East”: looking away from passing muon OM g m “South”: looking at oncoming muon g OM m “North”: looking away from oncoming muon g OM Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference15 m “South”: looking at oncoming muon g OM m “West”: looking at passing muon g OM m “East”: looking away from passing muon OM g KM3 Studies In depth look... Separate muon – OM distance, orientation Compare with expected photon time distribution dN g /dt : shape and normalization Orientations: m “North”: looking away from oncoming muon g OM Can't happen with only up-going n 's. Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference16 KM3 Studies Want to plot dN g /dt For each hit Rotate to muon frame, calc dca, theta, phi Calculate time residual (w/ Cherenkov model) Fill histogram in dca/theta/phi bin with time residual For each event Loop over each OM, rotate to muon frame Count # times OM is in a dca/theta/phi bin At the end, divide the two i.e. # hits per # chances to hit Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference17 KM3 Studies West, dca ~ 35m Similar to overall plots v3r* all look similar v4r0 offset from 0 v4r1 offset & no peak Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference18 KM3 Studies Describing the peaks Quantify by fitting with a Landau Look at peak position and width from fit In this example MPV = 0.1 ns Sigma = 0.7 ns Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference19 KM3 Studies West orientation Most probable value of Landau fit (MPV) versus muon – OM dist. v3r* near 0 Ngroup=1.38 in MC Largest for v4r* Ngroup=? in MC Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference20 KM3 Studies West orientation Width of Landau fit versus muon – OM dist. Larger for v4r* Expected & desired due to dispersion But v4r1 lacks any real “peak” Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference21 KM3 Studies West, dca ~ 35m Can compare to # g expected (MdJ's PDFs) PDF is wider PDF expects more light Note: PDF is for infinite track Normalization of MC affected by lack of down-going n 's? Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference22 KM3 Studies South, dca ~ 35m Same story for “south” orientation Expected, as OM is seeing a lot of direct light in this orientation Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference23 KM3 Studies East, dca ~ 35m For “east” orientation (looking away), need more events. Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference24 Photonics Studies MMC+Photonics has also been studied MMC : particle propagation Photonics : photon table generation Number and time of photons Finite muon tracks Point-like light sources for showers Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference25 Photonics Studies Water properties: same in KM3 and Photonics Taken from gen-water-optical-partic b.dat G4 SuNo was used in my Geant4 supernova study. Can be ignored. Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference26 Photonics Studies First look long ago KM3 = v3r6 (?) up + down n m files MMC = “old” Photonics also up + down n m files KM3 Photonic s Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference27 Photonics Studies First look long ago Obvious question: “What's up with those humps?” KM3 Photonic s Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference28 Photonics Studies These “old” Photonics tables... Had known problems! Thought (probably correctly) to be small Bug in the scattering code Result: too few photons scattered to shallow angles Expected to be a small effect Old angular acceptance for OMs Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference29 Photonics Studies Looking closer, though... Another problem found: big bins in the tables! Binning from IceCube They have many g tables 1 table for 1 layer of ice Need big bins to fit all these tables into memory Plus, they don't see direct g But we need fine binning! Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference30 Photonics Studies Looking closer at the old photon tables Strange “hump” features can be understood. Table sampling procedure: Table stores cumulative probability. Pick random # p=[0,1] Find bin containing p Linearly interpolate to find corresponding time Only works with fine binning! p interpolated time true c.d.f. real time Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference31 Photonics Studies Looking closer at the old photon tables If the c.d.f is linear, the p.d.f is constant! cdf(t)=A*t  pdf(t) = dC/dt = A time c.d.f. time p.d.f. Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference32 Photonics Studies Looking closer... Steps in the photon table interpolation become humps in the time residuals with the use of Ngroup=1.38 for all photons. Photonic s KM3 Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference33 Photonics Studies So... make new tables More bins! Claudio improved table generation Fixed scattering angle bug Implemented scattering code from KM3 Incorporated updated (Antares) PMT angular acceptance dic08 Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference34 Photonics Studies Old table binning (v1) R = 30 : [0, 580m] ^2 f = 9 : [0, 180º] Z = 65 : [-580, 580m] t = 50 : [0, 7000ns] ^2 # g = 40,000,000 Note: also found that some cells in the tables were empty (i.e. prb=0) New table binning (v4) R = 30 : [0, 550m] ^2 f = 12 : [0, 180º] Z = 60 : [-550, 550m] t = 130 : [0, 5000ns] ^2 # g = 500,000,000 Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference35 Photonics Studies With the new photon tables... Binning / interpolation effects harder to see. (Not just because they're hidden behind dashed lines.) However, they still exist! Could easily make tables with even finer binning. For tracking, probably should? Eventually, want to improve interpolation! Photonics v4 KM3 Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference36 Photonics Studies For a closer look w/o the bin lines: Smoother structure with new tables Wider than KM3 due to dispersion Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference37 Photonics Studies Looks ok, but.. what about the normalization? Can compare to p.d.f.'s calculated by Maarten Just as was done for KM3 earlier in this talk. Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference38 Photonics Studies For Anis+MMC+Photonics Generated muon neutrinos Used “new” photon tables (v4) E^-1 Same energy cut E [10, 10^5.5] GeV No event weights used Shower photons weighted by 1/shower_particle Note: with KM3, only e+, e- counted as shower. With MMC+Photonics, count all cascades except hadronic showers Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference39 Photonics Studies Differences in the MC samples: Energy spectrum not identical Plots unweighted, remember! MMC+Photonics: All n directions n + n Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference40 Photonics Studies MMC+Photonics With MMC, have events that KM3 doesn't Therefore, need to: Throw out events with no hits Check that that muon actually traverses the detector Possible in SeaTray, not KM3!  detector m OM dc a n Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference41 Photonics Studies Time residuals! For photons from muon Compare to true mu Direct + scattered Photonics scaled to v3r7 Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference42 Photonics Studies Time residuals! For photons from muon Photonics scaled to v3r7 Humps visible here As expected Photonics is wider Due to dispersion Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference43 Photonics Studies Time residuals! For photons from showers Direct + scattered Calculated w.r.t. Chkv assumption Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference44 Photonics Studies West, dca ~ 35m Photonics: Binning / interpolation effects visible And expected Normalization similar to KM3 Possibly less direct light? PDF expects more light Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference45 Photonics Studies Angular acceptance Photons from muons Up-going n 's only! Angle of incidence Assume Chkv emission angle Looks consistent dic08 in each code Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference46 Photonics Studies Angular acceptance Photons from muons Up-going n 's only! Angle of incidence Assume Chkv emission angle Looks consistent dic08 in each code Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference47 Photonics Studies Angular acceptance Photons from showers Up-going n 's only! Angle of incidence Assume Chkv emission angle Photon Studies KM3 MC MMC+Photonics Summary

Water Properties Phone Conference48 Summary KM3 Lack of dispersion in v3r* noticeable What reference Ngroup is used in v4r*? There seems to be a bug in v4r1. Direct light missing? Photonics New & improved tables have been made Linear interpolation of tables (c.d.f.'s) sucks After Antares shower GRB analysis, implement splines? Photon Studies KM3 MC MMC+Photonics Summary