Neutrino Astrophysics with Ice Cube KAEL HANSON UNIVERSIT

Neutrino Astrophysics with Ice. Cube KAEL HANSON UNIVERSITÉ LIBRE DE BRUXELLES 12 TH MARCEL GROSSMANN MEETING 13 – 18 JULY 2009 PARIS UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE

Two-minute Ice. Cube quiz Easy Question: Is Ice. Cube a Te. V-scale neutrino observatory? Answer: Yes, of course. Ice. Cube was designed to optimize the response to ν-induced µ in energy range between 1 -100 Te. V (Aeff, ν ≈ 10 m 2 at 10 Te. V). Muon energy loss related to Eµ above 1 Te. V. Angular resolution of 1°. Harder Question: Is Ice. Cube a Ge. V-scale neutrino observatory? Answer: Also yes. With the addition of the Deep. Core detector, the threshold energy is lowered from 100 Ge. V to 10 Ge. V. In addition, 4π solid angle acceptance possible due to shielding power of surrounding detector. Trick Question: Is Ice. Cube an Me. V-scale neutrino observatory? Answer: Yes and no. By turning the array into a simple photon counting system, it is possible to detect bursts of low-energy neutrinos emitted by supernova explosions. Discrete events are lost – you are left with a rate-vs-time. However, the effective volume is extremely large and with the resulting high statistics quite a bit of information can be extracted. JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 3

Motivation: why the supernova connection? § Only a handful of confirmed astrophysical sources of neutrinos – – – Neutrinos from the Sun Atmospheric neutrinos Neutrinos from 1987 A supernova explosion § Measurement of temporal profile of neutrino burst from SNe in our galaxy would be invaluable data for explosion models. § Realtime monitoring into worldwide burst alert network can give hours of advance warning to optical observers. § Finally, de gustibus non est disputandum JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 4

The Ice. Cube Collaboration R. Abbasi 24, Y. Abdou 18, T. Abu-Zayyad 29, J. Adams 13, J. A. Aguilar 24, M. Ahlers 28, K. Andeen 24, J. Auffenberg 35, X. Bai 27, M. Baker 24, S. W. Barwick 20, R. Bay 7, J. L. Bazo Alba 36, K. Beattie 8, J. J. Beatty 15, 16, S. Bechet 10, J. K. Becker 17, K. -H. Becker 35, M. L. Benabderrahmane 36, J. Berdermann 36, P. Berghaus 24, D. Berley 14, E. Bernardini 36, D. Bertrand 10, D. Z. Besson 22, M. Bissok 1, E. Blaufuss 14, D. J. Boersma 24, C. Bohm 30, J. Bolmont 36, O. Botner 33, L. Bradley 32, J. Braun 24, D. Breder 35, T. Castermans 26, D. Chirkin 24, B. Christy 14, J. Clem 27, S. Cohen 21, D. F. Cowen 32, 31, M. V. D'Agostino 7, M. Danninger 30, C. T. Day 8, C. De Clercq 11, L. Demirörs 21, O. Depaepe 11, F. Descamps 18, P. Desiati 24, G. de Vries-Uiterweerd 18, T. De. Young 32, J. C. Diaz-Velez 24, J. Dreyer 17, J. P. Dumm 24, M. R. Duvoort 34, W. R. Edwards 8, R. Ehrlich 14, J. Eisch 24, R. W. Ellsworth 14, O. Engdegård 33, S. Euler 1, P. A. Evenson 27, O. Fadiran 4, A. R. Fazely 6, T. Feusels 18, K. Filimonov 7, C. Finley 24, M. M. Foerster 32, B. D. Fox 32, A. Franckowiak 9, R. Franke 36, T. K. Gaisser 27, J. Gallagher 23, R. Ganugapati 24, L. Gerhardt 8, 7, L. Gladstone 24, A. Goldschmidt 8, J. A. Goodman 14, R. Gozzini 25, D. Grant 32, T. Griesel 25, A. Groß 13, 19, S. Grullon 24, R. M. Gunasingha 6, M. Gurtner 35, C. Ha 32, A. Hallgren 33, F. Halzen 24, K. Han 13, K. Hanson 24, Y. Hasegawa 12, J. Heise 34, K. Helbing 35, P. Herquet 26, S. Hickford 13, G. C. Hill 24, K. D. Hoffman 14, K. Hoshina 24, D. Hubert 11, W. Huelsnitz 14, J. -P. Hülß 1, P. O. Hulth 30, K. Hultqvist 30, S. Hussain 27, R. L. Imlay 6, M. Inaba 12, A. Ishihara 12, J. Jacobsen 24, G. S. Japaridze 4, H. Johansson 30, J. M. Joseph 8, K. -H. Kampert 35, A. Kappes 24, a, T. Karg 35, A. Karle 24, J. L. Kelley 24, P. Kenny 22, J. Kiryluk 8, 7, F. Kislat 36, S. R. Klein 8, 7, S. Knops 1, G. Kohnen 26, H. Kolanoski 9, L. Köpke 25, M. Kowalski 9, T. Kowarik 25, M. Krasberg 24, K. Kuehn 15, T. Kuwabara 27, M. Labare 10, S. Lafebre 32, K. Laihem 1, H. Landsman 24, R. Lauer 36, D. Lennarz 1, A. Lucke 9, J. Lundberg 33, J. Lünemann 25, J. Madsen 29, P. Majumdar 36, R. Maruyama 24, K. Mase 12, H. S. Matis 8, C. P. Mc. Parland 8, K. Meagher 14, M. Merck 24, P. Mészáros 31, 32, E. Middell 36, N. Milke 17, H. Miyamoto 12, A. Mohr 9, T. Montaruli 24, b, R. Morse 24, S. M. Movit 31, R. Nahnhauer 36, J. W. Nam 20, P. Nießen 27, D. R. Nygren 8, 30, S. Odrowski 19, A. Olivas 14, M. Olivo 33, M. Ono 12, S. Panknin 9, S. Patton 8, C. Pérez de los Heros 33, J. Petrovic 10, A. Piegsa 25, D. Pieloth 17, A. C. Pohl 33, c, R. Porrata 7, N. Potthoff 35, P. B. Price 7, M. Prikockis 32, G. T. Przybylski 8, K. Rawlins 3, P. Redl 14, E. Resconi 19, W. Rhode 17, M. Ribordy 21, A. Rizzo 11, J. P. Rodrigues 24, P. Roth 14, F. Rothmaier 25, C. Rott 15, C. Roucelle 19, D. Rutledge 32, D. Ryckbosch 18, H. -G. Sander 25, S. Sarkar 28, S. Schlenstedt 36, T. Schmidt 14, D. Schneider 24, A. Schukraft 1, O. Schulz 19, M. Schunck 1, D. Seckel 27, B. Semburg 35, S. H. Seo 30, Y. Sestayo 19, S. Seunarine 13, A. Silvestri 20, A. Slipak 32, G. M. Spiczak 29, C. Spiering 36, M. Stamatikos 15, T. Stanev 27, G. Stephens 32, T. Stezelberger 8, R. G. Stokstad 8, M. C. Stoufer 8, S. Stoyanov 27, E. A. Strahler 24, T. Straszheim 14, K. -H. Sulanke 36, G. W. Sullivan 14, Q. Swillens 10, I. Taboada 5, A. Tamburro 29, O. Tarasova 36, A. Tepe 35, S. Ter-Antonyan 6, C. Terranova 21, S. Tilav 27, P. A. Toale 32, J. Tooker 5, D. Tosi 36, D. Turčan 14, N. van Eijndhoven 34, J. Vandenbroucke 7, A. Van Overloop 18, B. Voigt 36, C. Walck 30, T. Waldenmaier 9, M. Walter 36, C. Wendt 24, S. Westerhoff 24, N. Whitehorn 24, C. H. Wiebusch 1, A. Wiedemann 17, G. Wikström 30, D. R. Williams 2, R. Wischnewski 36, H. Wissing 1, 14, K. Woschnagg 7, X. W. Xu 6, G. Yodh 20, S. Yoshida 12 1. 2. 3. RWTH Aachen University of Alabama University of Alaska Anchorage 4. Clark-Atlanta University 5. Georgia Institute of Technology 6. Southern University 7. University of California, Berkeley 8. Lawrence Berkeley National ab 2 0 0 9 M G X I I J U LLY 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. Humboldt-Universität zu Berlin Université Libre de Bruxelles Vrije Universiteit Brussel Chiba University of Canterbury University of Maryland Ohio State University TU Dortmund University U n. Ui v. Ne r. I s. Vi t. E y. R o f. SGI T h eÉn t L I B R E D’EUROPE 19. Max-Planck-Institut für 20. 21. 22. 23. 24. 2 5 E. D 26. University of Mons-Hainaut Kernphysik 27. Bartol Research Institute University of California, 28. University of Oxford Irvine 29. University of Wisconsin, École Polytechnique River Falls Fédérale 30. Stockholm University of Kansas 31. Penn State University of Wisconsin, 32. Penn State University Madison 33. Uppsala University of Wisconsin, 34. Utrecht University Madison 35. University of Wuppertal 3 6 I. TDÉE S Y Z e u t h e n UBn. R i v. U e r. X s i. E t y. L o. Lf EMSa, i n. U z NIVERS SLIDE 5

The Ice. Cube Detector § When complete 2012 – 80 in-ice strings – 6 deep core strings – 160 surface airshower tanks § 2009 “IC 59” status – 58 normal in-ice strings – 1 Deep. Core string – 118 surface tanks – 3730 channels in the DAQ – 1. 8 k. Hz trigger rate (CR µ) – 15 MB/sec raw data to tape – 50 GB per day filtered data over satellite link from Pole – 300 atmospheric neutrinos per day at trigger level § 2008 IC 40 run complete now analyzing data from this period (5/08 – 5/09) JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 6

Ice. Cube Deep. Core § Increase in detector eff. at 10 – 100 Ge. V § Ice. Cube strings form veto shield around core for 4π acceptance § Ice extremely clear at depth (λatt > 150 m) § Low-energy topics – – JULY 2009 MG XII Atmospheric neutrinos Neutrino mass hierarchy Dark matter Low energy astrophysical fluxes UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 7

Drilling and deployment JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 8

Digital Optical Module technology DOM Optical Large Area Photocathode 10” (500 cm 2) Hamamatsu R 7081 -02 bialkali PMT (peak QE 24% @ 420 nm); High QE variant (peak QE 35% @ 420 nm) used in Deep. Core DOMs Low noise < 300 Hz background counting rate in-ice (with artificial deadtime - see later) Glass / Gel Improvements Better transmission in 330 - 400 nm relative to AMANDA OM Optical calibration Each DOM is calibrated ε(λ) in the lab to about 7%; insitu flasher board additionally permits in-ice measurements DOM Electronics 15 of 3776 DOMs are useless, 35 more have serious problems. As of June 2009 all DOMs have been produced. “Smart” sensor digital technology Versatile FPGA design with option to expand / change programming at any point in lifecycle. Core of supernova DAQ resides inside DOM itself. Array Timing Handled in DOM logic - DOM-to-DOM timing good to 2 -3 ns using RAPCal method. Low power - 3. 75 W / DOM JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 9

Par t II TEV NEUTRINO ASTRO-PARTICLE PHYSICS WITH ICECUBE JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 10

Cosmic ray acceleration Model of CR acceleration in shocks of SN remnants fits observation but not confirmed. Te. V γ emission now established for many sources but could be from EM processes. Neutrino emission would be “smoking gun” for hadronic acceleration in these sources. JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 11

The neutrino sky JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 12

Detecting Te. V ν in Ice. Cube Neutrino undergoes CC or NC interaction with nuclear material, produces charged particles which emit Cherenkov radiation CC NC LINEAR “DOUBLE-BANG” CASCADES TRACKS νVHE CCUHE νorτ interacting νXνNC nuclear inside interactions μ or theτ detector via CCproduce scatter. produces either which the μ e (or τ) produces can EM primary or travel hadronic recoil for many cascades. kilometers and. These a τalong which produce linear can propagate track radiating enormous many 100’s Cherenkov amounts of m atof HE. photons Cherenkov τ decay in conical photons produces wavefront (10 a 8 about photons secondary track. per cascade Te. V) The extended radiated – leaving over range a 4π. very of taus The distinct extent and event. muons of means the Other cascade topologies vertexiscan ~10 as lie mwell: far longer outside “lollipop” at UHE detector and due“sugar to volume LPM. – detector Detector daddy. ” effective area volume is key is operational performance parameter. for cascades. Angular Good resolution energy resolution of 1° is achievable – ice is with caloric τ channel sophisticated medium. has no Poor ATM maximum angular background. likelihood resolution UHE track ντ fluxes reconstruction. can regenerate and are not absorbed by passage through Earth. JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 13

900 Pe. V cosmic ray event JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 14

Atmospheric Neutrinos Energy and baseline of atmospheric neutrinos: able to probe regions of parameter space for Lorentz violation and quantum decoherence completely inaccessible D. CHIRKIN ICRC 2009 New techniques developed for unfolding the energy spectrum of atmospheric neutrinos – here from IC 22 data. HEULSNITZ & KELLEY ICRC 2009 JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 15

Point Sources ½ year of IC 40 data – 175. 5 d live time 17777 evts – 6796 up, 10981 down I CE C UBE P RELIMINARY Dumm ICRC 2009 JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 16

Diffuse Neutrinos (IC 22) § Extraterrestrial neutrino flux harder than atmospheric neutrinos – look for HE excess of events § Tricky analysis – very sensitive to systematics in Monte Carlo simulation § IC 22 diffuse results are just now being released (Hoshina 2009 ICRC) § Use 3 ‘simple’ energy estimators – – – N c h : # of hit channels N p e : integral of reconstructed Q from DOM waveforms µ d. E/d. X : muon energy loss from photon tables § N c h and N p e showing significant excess at high multiplicity while µ d. E/d. X is consistent with atmopheric neutrino background § (Continuing) investigation of systematics associated with very primitive channel, charge counting § Limit from d. E/d. X analysis: JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 17

Neutrinos from Gamma-Ray Bursts • GRB fireball model predicts HE neutrinos from pγ interactions in GRB jet. • Satellite-triggers (Fermi/SWIFT) used to pinpoint the burst search windows and reduce background (looser cuts possible) Right after deployment of the 40 strings last year theoretically-visible-to-the-naked-eye GRB 080319 B went off. Unfortunately Ice. Cube was in maintenance mode at the time and only 9 strings were active. Search for high-energy muon neutrinos from the “naked-eye” GRB 080319 B with the Ice. Cube neutrino telescope ar. Xi. V: 0902. 0131 accepted by Ap. J JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 18

Neutrino-triggered optical follow-up § Ice. Cube ‘trigger’ to optical network (ROTSE) on neutrino multiplet: 2 or more neutrino events inside 100 s and 4° space angle (25 accidentals / year for M=2) § Motivation: GRBs, gamma-poor bursts, SNe with jets and Te. V neutrino emission § Program initiated end of 2008 JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 19

Dark Matter JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 20

Par t III MEV NEUTRINO ASTRO-PARTICLE PHYSICS WITH ICECUBE JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 21

Supernovae • For star of mass > 8 M☉ it is possible to develop Fe core ~ 1. 4 M☉. • Burning of Fe not exothermic – core collapses under it’s own gravity. • Almost all (99%) of gravitational energy of collapsing core is radiated away as neutrinos – approx 1053 erg. • Not all supernovae are collapse supernovae. Also Type Ia (used as standard candles in redshift measurements) which do not produce strong neutrino emission. • Core collapse are Type Ib/c and Type II JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 22

Observation of neutrinos from SN 1987 A JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 23

Detection of Me. V ν’s from SNe Primary detection channel is inverse βdecay Note this is only sensitive to the electron anti-neutrinos. Electron neutrinos (in particular those from the deleptonization burst) detected primarily from or The weak Cherenkov signal from any particular neutrinonucleus interaction for Ice. Cube-scale detector seen by at most one PMT. However, for sufficiently intense burst of finite duration, the counting rates of many such interactions recorded in many PMTs may be combined in manner to discriminate from background count rate. JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 24

Ice. Cube DOM Effective Volume (Me. V neutrinos) • SNe models give <E 3> ~ 15 Me. V • One may easily derive approx photon yield from positrons: 2500 • This gives per PMT, effective volume of 450 m 3 • 2 Mton target mass for IC 86 Effective volume scales as photocathode area, attenuation length, and E 3, thus dependent on temperature of SNe. We compute in E-independent manner the single photon eff volume, Veff, γ (note PMT response already folded into this expression): <Veff, γ> = 0. 185 m 3 JULY 2009 MG XII • 500, 000 counts above background expected for SN 1987 A at galactic center • cf. rms noise fluctuation of 3700 S/N = 130 : 1 UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 25

Photon counting in Ice. Cube § PMT counts pulse crossing discriminator threshold of 0. 25 pe § DOM logic maintains virtual scalers: 4 -bit counters with integration time 1. 64 ms. § Edges of bins defined in DOM clock frame – translation to global time via RAPCal method § Introduction of artificial deadtime important to optimize S/N in presence of optical artifacts: PMT after-pulsing and other late light effects. § The scalers from each channel collected and sent to assembly phase where they are chronologically sorted and then written to disk file (3 MB/sec) for – – handoff to realtime supernova alert system permanent storage JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 26

Supernova detection in realtime • Realtime supernova alert system at pole consumes data files emitted by DAQ system • Merge and globally align scaler bins coming from DOMs • Compute the following statistics to search for excess counts SIGNAL + ERROR BACKGROUND ELIMINATION Internally we generate multiple triggers per day for monitoring purposes. Of these, high significance triggers sent to SNEWS via 24/7 Iridium satellite messaging system. SNEWS alert rate < 2 / week – average latency is approx. 10 min. JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 27

SNe ν’s as probes of the supernova explosion mechanism • Various phases of evolution signaled by change in neutrino flux • infall • neutronization burst • accretion • cooling • Theoretical models still have trouble producing explosion – neutrinos may be critical ingredient restarting the stalled shockwave • For very massive stars > 25 M☉ supernova explosion may be interrupted by formation of a black hole: optical burst not present – neutrino fluxes characterized by increase in temperature and eventual truncation. JULY 2009 MG XII UNIVERSITÉ LIBRE DE BRUXELLES, UNIVERSITÉ D’EUROPE SLIDE 28