neutrino astronomy francis halzen university of wisconsin

Transcription

1 neutrino astronomy francis halzen university of wisconsin

2 50,000 year old sterile ice instead of water

3 we built a km 3 neutrino detector 3 challenges: drilling optics of ice atmospheric muons search for the sources of the Galactic cosmic rays search for the extragalactic cosmic rays gamma ray bursts active galaxies particle physics, mostly dark matter IceCube.wisc.edu

4 AMANDA Event Signatures: Muons neutrino interaction muon track n m + p m +

5 analog transient wave recorder

6 IceCube / Deep Core detects Cherenkov light from showers and muon tracks initiated by neutrinos detects ~220 neutrinos and 1.7x10 8 muons per day threshold 10 GeV angular resolution 0.4~1 degree 5320 Digital Optical Modules (DOM)

7 completed December 18, 2010 IC Season IC Season IC Season IC Season IC Season IC Season IC Season

8 IceCube event display time = color (red purple) size = number of photons

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12 n

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14 89 TeV 14

15 250,086 photons 10 PeV in detector probablity atmospheric: 10-3

16 electron neutrino

17 seen: 14 events predicted: 3 atmospheric and 4 background

18 we built a km 3 neutrino detector 3 challenges: drilling optics of ice atmospheric muons search for the sources of the Galactic cosmic rays search for the extragalactic cosmic rays gamma ray bursts active galaxies IceCube.wisc.edu

19 IceCube Site nozzle delivers 200 gallons per minute 7 Mpa 90 degree C 4.8 megawatt heating plant

20 IceCube drilling to best low background site on Earth: radio-pure ice no seasonal variations (temperature, humidity, ) shielded from cosmic rays by IceCube veto DM-ice, DeepCore upgrades (towards proton decay?) < 700K$ per string of 60 ten inch PMTs (data to your pc)

21 absorption length 220m

22 scattering length 47m

23 we built a km 3 neutrino detector 3 challenges: drilling optics of ice atmospheric muons search for the sources of the Galactic cosmic rays search for the extragalactic cosmic rays gamma ray bursts active galaxies IceCube.wisc.edu

24 muons detected per year: atmospheric* m 7x10 10 atmospheric** n m > 8x10 4 cosmic n m ~ 10 * > 2000 per second ** 1 every 6 minutes

25 within trigger time window down down down up

26 (not) final performance

27 IceCube performance then and now PeV: x2 EeV: x3 IceCube neutrino area predicted performance (blue) Astroparticle Physics 20, 507 (2004) neutrino mirror area Gonzalez-Garcia et al.

28 > 16 s < 1 deg moon shadow

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30 improved angular and energy resolution soon

31 on to IceCube science we measure the flux of atmospheric muons and neutrinos at higher energies and with better statistics than previous experiments. Any deviations from what is expected is new neutrino physics or new astrophysics. We just look for surprises.

32 IceCube-40 atmospheric neutrino spectrum

33 zenith angle two analyses

34 3+1 3

35 zenith angle two analyses systematics!!! K/p ratio zenith acceptance of modules ice CR composition 36

36 early astronomy directions of ~ 600 neutrinos AMANDA 2000

37 IceCube 40 strings operated days northern sky: neutrinos search for clustering high energy (>> 100 TeV) southern sky: muons

38 nothing seen in IC40 but not finished yet! nothing expected next?

39 limits (symbols) / sensitivies (lines) to point sources ANTARES southern hemisphere northern hemisphere SUPER-K AMANDA next unblinding IC40+59 IC40 KM3: 2X3km 3 detectors 1-year sensitivity

40 we built a km 3 neutrino detector 3 challenges: drilling optics of ice atmospheric muons search for the sources of the Galactic cosmic rays search for the extragalactic cosmic rays gamma ray bursts active galaxies IceCube.wisc.edu

41 Galactic cosmic rays : must produce pionic g-rays in interactions with hydrogen in Galactic plane (1 proton cm -3 ) produce TeV gamma rays Galactic extragalactic cr + p pions p 0 gg trace cosmic rays

42 the accelerator? TeV photons trace the density of the molecular clouds

43 galactic plane in 10 TeV gamma rays : supernova remnants in star forming regions Southern Hemisphere Sky Standard Deviations milagro 210

44 neutral pions are observed as gamma rays g p 0 g p + p - n m m + n m - charged pions are observed as e + e + e - g e - neutrinos e + g m + e + n e n m n m +n m = g + g

45 cygnus region : Milagro translation of TeV gamma rays into TeV neutrinos : 3 ± 1 n per year in IceCube per source

46 preliminary Milagro: Galactic plane > 10 TeV 3s 5s n m +n m = g + g time in years

47 20,000 atmospheric neutrinos later

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49 IC22 and IC40 : muon astronomy (!) IC22 IC40 IC59 Different geometries, same structure

50 10 TeV to several 100 TeV cosmic rays in IceCube we map the highest energy Galactic cosmic rays, but their gyroradius is < 1 pc in microgauss magnetic field closest sources > 100 pc 10 TeV 2 KHz 3 deg resolution should not point! that s why we detect neutrinos!

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55 Vela closest supernova remnant strongest gamma ray source

56 we built a km 3 neutrino detector 3 challenges: drilling optics of ice atmospheric muons search for the sources of the Galactic cosmic rays search for the extragalactic cosmic rays gamma ray bursts active galaxies IceCube.wisc.edu

57 collapse of massive star produces a gamma ray burst spinning black hole photons and protons coexist in the fireball if GRB are the sources of the cosmic rays neutrino production

58 flux Radio CMB Visible GeV g-rays energy (ev) 410 photons of 2.7 K or erg/cm 3 / galactic cosmic rays erg/cm3 galactic cosmic rays erg/cm 3 extragalactic cosmic rays 3x10-19 erg/cm 3

59 Cosmic Rays & GRBs Extragalactic observed energy density of extragalactic CR: 3x10-19 erg / cm 3 Gamma-Ray Bursts: 2x10 52 ergs x 300/Gpc 3 x yr 3x10-19 erg / cm 3 GRBs provide environment and energy to explain the extragalactic cosmic rays!

60 n and Neutrino g beams Beams: : heaven Heaven & and Earth earth NEUTRINO BEAMS: HEAVEN & EARTH black hole radiation p + g n + p + ~ cosmic ray + neutrino p + p 0 ~ cosmic ray + gamma

61 collide cosmic rays of GRB origin with microwave photons + 0 p + g n + p and p + p cosmic rays from n-decay

62 GRB origin of cosmic rays challenged p 0 gamma rays after cascading in the microwave background p + neutrinos

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64 GRB on probation 3x10-19 erg/cm 3 over years = 5x10 44 TeV Mpc -3 yr reduce by ten more reasonable 2x10 51 erg per GRB cannot explain the cosmic rays above the knee escape IceCube 40 string diffuse bound new prediction for year data Waxman: 12.4 events Guetta: 14.5 events none seen

65 GRB only yield the highest energy particles, not the cosmic rays above the knee

66 NOT a GRB neutrino(?) within 40 s duration of the burst azimuth of burst deg observed /- 0.3 we keep looking!!!

67 1~1.5 events/yr

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69 3+1 neutrinos? ~20σ without oscillations with oscillations IceCube science

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71 WIMP Capture and Annihilation c n m n DETECT c + c W + W n + n b + b n + n

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74 conclusions Hess and still no conclusion the instrumentation is in place supernova remnants and GRB are in close range!

75 back up slides

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77 arxiv:

78 neutrinos from the center of the Galaxy

79 South Pole 2000 AMANDA South Pole Dome 1500 m 2000 m [not to scale] Amundsen-Scott South Pole station

80 AMANDA: simple high voltage supplied via (coax, twisted pair, fibre optic) cable analog photomultiplier signal up via same cable successful photomultiplier pulses after 2 km not pretty WHAT DO WE REALLY NEED? complex wave form information (scattering in ice) large dynamic range; more that 10 6 low power consumption stable operation, easy calibration ANSWER : ANALOG TO DIGITAL CONVERSION

81 Each optical module must become a complete semi-autonomous data acquisition platform, linked in an all digital decentralized network Let s make 5000 complex tethered satellites and bury them forever in ice Will the cold keep them from working? Nothing like this has ever been done What if we make a mistake we can t fix?

82 oscillator F P G A 750 years mtbf ATWD

83 architecture of independent DOMs 10 inch pmt LED flasher board main board HV board

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85 each DOM is independent: continuously sends timestamped wave forms

86 neutrino flavors

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88 cosmic neutrinos: energy: >> 100 TeV IceCube 40 atmospheric neutrino spectrum

89 supernova 10 6 eventswith1.7m secsampling start : 3ms at 95% CL

90 2 nanosecond timing across 1 km 3

91 The Digital Optical Module (DOM) Onboard capture of PMT waveforms 300 MHz for ~400 ns with custom chip 40 MHz for 6.4 µsec with comm. fast ADC Absolute timing resolution < 2 ns (RMS) Dynamic range ~1000 p.e./10 ns Deadtime < 1% Noise rate ~700 Hz (260 Hz w / artif. deadtime) Failure rate < 1% Digitized Waveform

92 Muon event in IceCube downgoing cosmic ray muon ~ 2700 per second M. Santander - TeV cosmic ray anisotropy in IceCube (Prelim exam) - 03/07/

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94 cassiopeia A supernova remnant in X-rays 10-3 of energy released transformed into acceleration E -2 spectrum acceleration when particles cross high B-fields

95 GRB protons and photons coexist in the fireball n production proton flux = observed cosmic ray flux (WB) observation of 117 burst with IceCube-40 strings 4 events expected, none seen

96 energy in extra-galactic cosmic rays is ~ 3x10-19 erg/cm 3 2x10 52 erg per gamma ray burst energy in cosmic rays ~ photons

97 104 drilling and deployment to 2500 m in less than 2 days 3.5 cm/second