SPICE Mie [mi:]

Dmitry Chirkin, UW Madison

Updates to ppc and spicePPC:

• Randomized the simulation based on system time (with us resolution)• Added the implementation of the simple approximate Mie scattering function• New oversized DOM treatment (designed for minimum bias compared to oversize=1):

oversize only in direction perpendicular to the photon time needed to reach the nominal (non-oversized) DOM surface is added re-use the photon after it hits a DOM and ensure the causality in the flasher simulation

Spice:

• Fixed code determining the closest DOMs to the current layer (when using tilted ice)• Perform simultaneous global fit for py, time offset, scattering vs. absorption correlation coeff.• Optimize use of high-event flasher simulation: use 250-event simulation in the dust peak, 10 elsewhere. Eventually use 250-event simulation for the entire depth range.

nominal DOMoversized DOM

oversized ~ 5 times

phot

on

Timing of oversized DOM MC

xR=1defaultdo not track back to detected DOMdo not track after detectionno ovesize delta correction!do not check causalitydel=(sqrtf(b*b+(1/(e.zR*e.zR-1)*c)-D)*e.zR-hdel=e.R-OMR

Flashing 63-50 63-48

64-48

64-52

xR=1

default

Simplified Mie Scattering

Single radius particles, described better as smaller angles by SAM

Also known as the Liu scattering function

Introduced by Jon Miller

New approximation to Mie

fSAM

Dependence on g=<cos()> and fSAM

g=<cos()> fSAM

0.8 00.9 00.95 0

0.9 0.30.9 0.50.9 1.0

flashing 63-50 64-50

New global fit to everything in SPICE

1. For some starting values, find best values of sca ~ abs.

2. Find best values of py, toff, fSAM, sca, abs, llhtot, …

py photon yield factor

toff global time offset (rising edge of the flasher pulse)

fSAM fraction of SAM contribution to the scattering function

sca scaling of scattering coefficient

abs scaling of absorption coefficient

3. Repeat until converged (~3 iterations)

4. Refine the fit with sca and abs independent from each other

Charge only

Ful

l lik

elih

ood

with

tim

ing

Verification with toy simulation

Input table

Simulated60 x 250 events

Reconstructed table

with 10 event/flasher

250 event/flasherIn the dust peak

Correlation with dust logger

With 10 events/flasher, 250 in dust peakWith 250 events/flasher everywhere

Plots for individual flashers

SPICE Mie

AHA

Plots for CORSIKA/data SPICE Mie

AHA

Plots from Anne (CORSIKA IC40)

Plot from Jacob Feintzeig

SPICE Mie: ice coefficients

“unresolved” systematics: resolved

Minimum is in the same place with both likelihoods!

Conclusions

SPICE Mie is great

fits timing perfectly!

SPICE paper is available (v. 0.01)

please comment