Ice Cube a new window on the Universe
Ice. Cube a new window on the Universe • • Muons & neutrinos Neutrino astronomy Ice. Cube science Status & plans Tom Gaisser for the Ice. Cube Collaboration Arequipa, Peru, Sept. 1, 2008
• Uppsala University • Stockholm University • University of Oxford Universität Mainz • Humboldt Univ. , Berlin • DESY, Zeuthen • Universität Dortmund • Universität Wuppertal • MPI Heidelberg • RWTH Aachen University Utrecht • Univ Alabama, Tuscaloosa • Univ Alaska, Anchorage • UC Berkeley • UC Irvine • Clark-Atlanta University • U Delaware / Bartol Research Inst • Georgia Tech • University of Kansas • Lawrence Berkeley National Lab • University of Maryland • Pennsylvania State University • University of Wisconsin-Madison • University of Wisconsin-River. Falls • Southern University, Baton Rouge Chiba University • Universite Libre de Bruxelles • Vrije Universiteit Brussel • Université de Mons-Hainaut • Universiteit Gent • EPFL, Lausanne Univ. of Canterbury, Christchurch The Ice. Cube Collaboration
The neutrino landscape Expected flux of relic supernova neutrinos Lines show atmospheric neutrinos + antineutrinos nm ne Astrophysical neutrinos (WB “bound” / 2 for osc) Solar n Prompt n RPQM for prompt n from charm Bugaev et al. , PRD 58 (1998) 054001 Slope = 2. 7 Slope = 3. 7 Cosmogenic neutrinos
Atmospheric neutrinos p • Produced by cosmic-ray interactions – Last component of secondary cosmic radiation to be measured – Close genetic relation with muons • p + A p± (K±) + other hadrons • p± (K±) m± + nm (nm) • m± e± + nm (nm) + ne (ne) – Above ~2 Ge. V muons reach the ground before decaying p m e ne nm
High-energy atmospheric neutrinos Primary cosmic-ray spectrum (nucleons) Nucleons produce pions kaons Kaons produce most nm for 100 Ge. V < En < 100 Te. V charmed hadrons that decay to neutrinos Eventually “prompt n” from charm decay dominate, …. but what energy?
Neutrinos from kaons Critical energies determine where spectrum changes, but AKn / Apn and ACn / AKn determine magnitudes New information from MINOS relevant to nm with E > Te. V
Te. V m+/m- with MINOS far detector • 100 to 400 Ge. V at depth > Te. V at production • Increase in charge ratio shows – p K+ L is important – Forward process – s-quark recombines with leading di-quark – Similar process for Lc? x 1. 37 1. 27 x Increased contribution from kaons at high energy
Neutrinos from charm • Main source of atmospheric n for En > ? ? • ? ? > 20 Te. V • Large uncertainty! Gelmini, Gondolo, Varieschi PRD 67, 017301 (2003)
Angular dependence For e. K < E cos(q) < ec , conventional neutrinos ~ sec(q) , but “prompt” neutrinos independent of angle Uncertain charm component most important near the vertical
Detecting neutrinos • Rate – Convolution of: • • • Neutrino flux Absorption in Earth Neutrino cross section Range of muon Size of detector Probability to detect nm-induced muon:
Neutrino effective area • Rate: = ∫fn(En)Aeff(En)d. En • Earth absorption – 10 -100 Te. V • cos(q) > -0. 8 • Main effect near vertical – Higher energy n’s absorbed at larger angles
Ice. Cube acceptance, resolution
Atmospheric muons in n telescopes Angular-dependence of muons in SNO at 6000 m. w. e. depth Crossover of n-induced m at 60 o ! Depths of large neutrino telescopes Million to 1 background to signal from above. Use Earth as filter; look for neurtinos from below.
Muon signal from all directions Downward atmospheric muons Upward neutrino-induced muons Patrick Berghaus et al. , Cosmo-08 and ISVHECRI-08
Ice. Cube 22: signal from below at trigger level, background / signal = 1000 / 1 Efficiency at final cut level ~ 10% Unrelated muons from different cosmic-ray primaries in the same time window
IC 22 Events ( Red hits = early; yellow/green/blue = later ) Ice. Cube DOM locations blue, AMANDA OM locations red Downward cosmic-ray event (“muon bundle”) Upward candidate n event
Neutrino astronomy with Ice. Cube Accretion and jets formation A common phenomenon on both stellar & galactic scales: Matter falls onto black hole or neutron star driving collimated, relativistic jets perpendicular to the disk AGN, other extra-galactic sources Micro-quasars, galactic g sources Expect hard spectrum (like cosmic-ray source, E-2 ) Cutoffs ~10 – 100 Te. V expected for galactic sources M. Urry, astro-ph/0312545
Limits on excess of n above atmospheric background
Point source search with 7 years of AMANDA 3. 8 yrs livetime 26 candidate sources Jim Braun, UW Madison, presented at Cosmo-08
Jet breakout in GRB following collapse of massive progenitor star 0 seconds fireball protons and Image: W. Zhang & S. Woosley See astro-ph/0308389 v 2 photons interact Pe. V Te. V Ee. V - 10 seconds afterwards fireball protons interact with remnant of the star afterglow protons interact with interstellar medium
Slide from Alexander Kappes
Search for neutrinos from GRB models Waxman-Bahcall PRL 78 (1997) 2292 Murase-Nagataki A PRD 73 (2006) 063002 All flavor limits by AMANDA Cascade (Rolling) Cascade (Trig & Roll) Supranova, Razzaque et al. PRL 90 (2003) 241103 Choked bursts Meszaros-Waxman PRL 87 (2001) 171102 Limits on neutrinos from GRB from AMANDA: -from cascades (ne, nt), Ap. J. 664 (2007) 397 -from neutrino-induced muons, Ap. J (to be published) nm search
Prospects for detecting GRB n’s with Ice. Cube • Advantage: – time window and direction defined by satellite observation of the GRB – Observation of coincidences removes background • AMANDA limits – Already disfavor some models – Sensitivity close to classic Waxman-Bahcall fireball prediction (expected ~ 1 n in 400 GRBs) • Ice. Cube sensitivity ~20 times AMANDA – 200 GRB / yr expected from GLAST – Expect 3 s detection of Waxman-Bahcall level in 70 GRB with full Ice. Cube – Non-observation would indicate GRB jets are pure Poynting flux (Blandford) rather than baryon loaded plasma (Piran, Meszaros, …) • Ice. Cube to send alerts to ROTSE
Shadow of the Moon in IC 40 Laura Gladstone, Jim Braun Cosmo-08
Related science with Ice. Cube • Archaeology of ice • Physics by monitoring counting rates: – Supernova watch – Solar activity, solar flares, etc. • Indirect search for dark matter: – WIMP annihilation in the Sun • Neutrino physics – Oscillations at high energy? – Energy dependence of neutrino cross section • Measure Earth density profile – Use energy and angle dependence of 10 -100 Te. V atmospheric neutrinos (The Economist, November, 2007) • High-altitude pressure, weather from muon & Ice. Top counting rates • High-energy cosmic rays (< 1 Pe. V to > 1 Ee. V )
13 Dec 2006 solar flare in Ice. Top During transition from TICL to ICL
Cosmic-ray physics with Ice. Cube • E-spectrum • Composition – Coincident events: m / e – Knee to transition from galactic • Calibration, partial veto for Ice. Cube DIRECT Air Showers Galactic cutoff ~ 3 x 1015 e. V ? Extra-galactic component ? Tevatron LHC
Composition with air showers • Proton penetrates deep in atmosphere – Shower max deeper – ( mu / e ) smaller – muons start deeper • Heavy nucleus cascade starts high – shower max higher up – ( mu / e ) larger – muons start higher proton heavy nucleus
Depth of maximum via air Cherenkov or fluorescence 1018 e. V proton Depth of Ice. Top
Preliminary Ice. Top Spectrum
Composition from angular dependence of spectrum Protons only Iron only 5 -compnents
Composition from In-ice / Ice. Top (m/e) • Use coincident events • Reconstruct muon bundle in-ice to obtain energy deposition by muons • Reconstruct surface shower to get Eprimary • Require consistency with angular distribution and m/e at the surface Simulation for SPASE-AMANDA
An Ee. V event in IC 40
Ice. Cube photo gallery 125 m High Energy Earth Science Tokyo, June 26, 2008 Tom Gaisser Photo: James Roth 17 -12 -2007
• • 22 strings running in 2007 18 strings deployed in 07 / 08 Ice. Cube now 0. 5 km 3 Complete in 2011
Drilling
Hose reel & tower, Drill Camp
DOM deployment
Ice. Top Nov 23, 2007 Photo: James Roth, Dec 8, 2007 Photo: Jim Haugen
Cables Photos: Jim Haugen Photo: Justin Vandenbroucke
ICL: Ice. Cube Laboratory and Data Center • Commissioned for operation in January 2007. • 17 racks of computers • Power: 60 k. W total for full Ice. Cube • Initiate runs and monitor detector from North • Filtered data sent by satellite
Plan low energy core for Ice. Cube; will replace AMANDA Concept: define fiducial volume. Contained vertex with no hits in outer “veto” region is a neutrino candidate. Opens some phase space for downward neutrinos. AMANDA 1500 Dust layer Very clear ice 2500 Deep Core
2008 -09 plan 2 test tanks Deployed Dec 03 ? ? ?
nner core Consists of 6 specially configured strings between 7 standard Ice. Cube strings Special strings have 50 DOMs, 7 m spacing below dust layer Lower En threshold New string postions Standard Ice. Cube 36
Status • Ice. Cube construction & operation – Drill season: Nov-Dec-Jan – Commission new detectors: Feb-March – Start new science run April, continue through drilling • 2007 run – 22 strings, 26 surface stations, 05/07 to 03/08 – Analysis underway, some results available • 2008 – 40 strings, 40 surface stations, 04/08 to 03/09 – Running now, filtered data sent by satellite to UW
Plans • 08/09 season – – Reductions due to fuel costs & NSF budget +16 to 19 strings; +19 Ice. Top stations Includes first special string of inner core Start IC 56 science run April, 2009 • 09/10 season – Plan to install 15 + 5 strings – Complete inner core with 5 special strings • 10/11 season to complete Ice. Cube construction
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