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Status of km3 check. ANTARES MC WG, Tue 12th Jun 2012. Km3 Progression: a reminder…. rbr v0.1: used km3 v3r7 Treated direct photons from electrons as being emitted at the Cherenkov angle Km3 v3r9: fixed ‘single-band issue’ direct photons from electrons treated as scattered photons.
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Status of km3 check ANTARES MC WG, Tue 12th Jun 2012
Km3 Progression: a reminder… • rbr v0.1: used km3 v3r7 • Treated direct photons from electrons as being emitted at the Cherenkov angle • Km3 v3r9: • fixed ‘single-band issue’ • direct photons from electrons treated as scattered photons. • Fix acts to reduce event rate (less ‘on-cone’ hits) • Fixed ‘energy-loss mismatch’ between gen and km3 • Previously, e-loss between 0.3 and 0.72 GeV was discarded • Fix acts to increase the event rate (more eloss in km3) • v3r10: only cosmetic changes • Km3 v4 • Added chromatic dispersion (no obvious net effect expected) • V4r0 v4r1: buggy. Use v4r2 • rbr v2: • Modify hit v4r2 to use the new angular efficiency via aa.txt and aa.f
Behaviour v3r7-v4r2 • Step 1: Use toy experiments to assess behaviour • Run 3x106 toy events per trial • B1: 1 TeVmuon, 25m PMT distance, pointing away • B2: 1 TeVmuon, 25m PMT distance, pointing towards • B3: 1 TeVmuon, 50m PMT distance, pointing away • B4: 1 TeVmuon, 50m PMT distance, pointing towards • This analysis is complete as of 11:30 am today • Step 2: Use rbr runs • use exactly the same MUPAGE/GENHEN events (only km3 and TE randomness applies). • Use 10 runs: 34433, 35360, 35750,36430, 37230, 37340, 53240, 53450, 53620, 54250. • Analysis incomplete: 50% computation finished + need to decide how to characterise output
What I did exactly… • v3r7, v3r9, v4r2: • Check out clean copy and makeexecutables • Build gen & hit tables and run km3 w. standard options • v3rX have ¼ statistics of v4rY (smaller internal arrays) • Gen rad file: gen-water-radii-5-20s-partic-0.0075.dat • v4r2 rbr: • Tables from /sps/km3net/mc/rbr/v2/prod_inputs/km3tables/ • Use clean co-ed and built km3mc v4r2 • May have used a different gen radii file! • Ran many events on the cluster and got… results!
What can we conclude from this? • Not as much as we might expect! • Effect in slides 9-12 due to chromatic dispersion (c-d)(main diff between v3 and v4 plots) • c-d acts to delay the peak • Of course we then have less photons after a certain time! • But… • Both v4r2 for cases B1 and B3 (facing away) have definitely lower cumulative distributions than v3rX • Could this be the source of the reduced counts? • Q: What is the effect on rbr simulations? • A: Still to find out…
OK, onto the future… • v4r3: • Minimum effang of 10-6 (solves 2nd early-photon problem) • New theta-binning (BELO/BEHI of 0.45) (‘v4r3 pure’) • Solves early-photon problem • Effect on total photon number: increases it! (no hard reason) • Added seawater to gen (expect ~4% fewer photons) (‘v4r3 sea’) • v4r4 • Wavelength-dependent ‘eta’ (fraction of Rayleigh) (‘v4r4 MR’) • New hit method to input and sample PMT parameters: implement new effective angle calculation (‘v4r4 new effang’)
Conclusion on recent updates • Changes v4r2-v4r3: BELO/BEHI most important • All other changes minsmall • Effect of new angular efficiency: • v4r2vsrbr_v4r2 (slides 9-12, bluevspink) • slightly reduced number of hits for PMTs facing towards a track • Increased number of hits for PMTs facing away from the track • v4r4vsv4r4_new effang(slides 19-22, light blue vsyellow) • Reduced number of hits for PMTs facing towards a track • Increased number of hits for PMTs facing away from the track • This is inconsistant!
Effang plot Difference can not be due to different implementations of the effective angle!
Possible explanation? • When compiling km3 with the function ‘getaa’, I had to remove all binaries and recompile from scratch to avoid insanity. • There is no known reason for this behaviour: could be f77 or make problem. • Perhaps something strange gets introduced here?
Where commeth the wobbles? • Scattered photons from muons!
Why? • Speed up in km3: merge muon track segments at large distances for scattered photons • Tracks: intrinsically 1m • Merging: x3, x9, and x27 at comparable distances • Merging is too coarse! • Solution: • multiply all merging distances by a factor • Implementation: allow FFKEY ‘DIVTK [float]’ to km3 • Test: use DIVTK 2. in B4
Problem solved • DIVTK=2 seems to work!