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Englacial arrays for detection of cosmogenic neutrinos at the South Pole IceCube radio extension & ARA Status

Englacial arrays for detection of cosmogenic neutrinos at the South Pole IceCube radio extension & ARA Status and results APS 2011, Anaheim CA. Hagar Landsman, University of Wisconsin, Madison. The plan for the next 10 minutes (and the next 5 years). IceCube RF extension

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Englacial arrays for detection of cosmogenic neutrinos at the South Pole IceCube radio extension & ARA Status

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  1. Englacial arrays for detection of cosmogenic neutrinos at the South PoleIceCube radio extension&ARAStatus and resultsAPS 2011, Anaheim CA Hagar Landsman, University of Wisconsin, Madison

  2. The plan for the next 10 minutes(and the next 5 years) IceCube RF extension Review of current hardware Status Stay tuned for the next 2 talks ARA – Askaryan Radio Array New collaborative effort The grand scheme Results from last season Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  3. IceCube’s radio extension • In ice digitization . Combination of ANITA/IceCube/RICE technologies: • 2 clusters in 2006-2007 • 3 clusters in 2008-2009 • Depth of 1450 m or 300 m • AKA “AURA” •  Envelope detection. • 6 units deployed at -35, -5 meters (2009-2010) • 6 units in other depth/location • (On top of a building, terminated, -250m) • AKA “SATRA” • Calibration Set of transmitters and passive antennas for calibration (including cable symmetrical antennas) Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  4. Counting house surface junction box IceCube-radio hardwareFully digitized WFs Use IceCube’s resources: holes, comm. and power Each Cluster contains: • Digital Radio Module (DRM) – Electronics • 4 Antennas – With front end electronics • 1 Array Calibration Unit (ACU) - Transmitter Deployed above the IceCube array: • “Free” Deep holes • “Free” Power distribution and communication Signal conditioning and amplification happen at the front end • RICE Broad band fat dipole antennas centered at 400 MHz • 450 MHz Notch filter • 200 MHz High pass filter (2 units with 100Mhz) • ~50dB amplifiers (+~20 dB in front end) Signal is digitized and triggers formed in DRM (a’la’ANITA) • 512 samples per 256 ns (2 GSPS). • Wide frequency range and multiple antennas are required for triggering Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  5. Transient style detection Nick name: SATRA - (Sensor Array for Transient Radio Astrophysics) Transient detector (“SATRA”) • 6 in ice units on 3 strings in holes #8, #9 and #16 • 1 antenna each: 2 antennas per hole. • 35m and 5 m deep • Each pair of antennas has a local-coincidence triggering • Dry holes • Log amp envelope detection sjb DAQ box 5 m 30 m satra IceCube cable Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  6. Some results Ice index of refraction n(z) Ice Attenuation Length (point to point) Environmental noise Reconstruction algorithms See Mike Richman’s and Chris Weaver’s talk 6 Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  7. The ARA Vision • 80 km2 area • 37 stations equally spaced on a triangular grid • Large separation between stations (1.3km) • 3 stations forms a “super cluster” • Sharing power, comms, and calibration source • Station: • 4 closely spaced strings • 200m deep • Digitization and Triggering on surface DAQ Housing Vpol Antenna Hpol Antenna • String: • 4 antennas, V-pol and H-pol • Designed to fit in 15cm holes • 150-800 MHz sensitivity • Cable pass through antenna ~30m Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  8. ARA Concept The goal is to count events, not reconstruct the angles as would be needed for observatory class instrument • Optimized for neutrino counting: • A single station can provide and form a trigger • Decreases trig time window, lower background • and therefore thresholds. • Lowers the energy threshold. allowing single string hits. • Detecting down-going events: (4.4sr) • Between +45 above, -5 below horizon • Deep ice contributes in higher energies 200m ~30m 1300m γ 2.5 km Interaction vertex RF radiation Hagar Landsman ARA Spring 2011, Madison

  9. ARA - A New collaboration was born NSF Grant “Collaborative Research: MRI-R2 Instrument Development of the Askaryan Radio Array, a Large-scale Radio Cherenkov Detector at the South Pole“ phase 1 funded More than 10 institutions from US, Europe, Taiwan, Japan Including IceCube & ANITA & RICE leading institutes. • 2010-2011 • Install testbed • EMI survey away from the station • Test ice properties • Testing station prototypes (antennas and electronics) • Calibration activities • Install 3 deep RF Pulsers • Conduct Drilling tests • Install 3 Wind turbines for testing 9 Hagar Landsman ARA Spring 2011, Madison

  10. This season’s on ice achievementsARA Test Bed • Successfully installed ~3.2 km away from the Pole. • 16 antennas at different depths, down to ~20m. • Signal digitization and triggering happens on a central • box on the surface. • Power and comms through cables. • Current status: • Detector is up and running. • Very high efficiency and live time. • No unexpected EMI source. • Up to now, no evidence for wind generated EMI Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  11. This season’s on ice achievementsARA Test Bed – Trigger rates Austral winter sssshhhhh Austral summer A lot of on-ice activity 9:00 pm weather balloon launch 9:00 am weather balloon launch • Test Bed is taking data continuously • Trigger rates are low and stable – below 4 Hz • Clear winter/summer rate difference • Weather balloon launches CW clearly seen Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  12. This season’s on ice achievementsARA Test Bed – Galactic center Noise measured on the surface antennas Ch 2 preliminary Ch 1 Total Thermal Expected galactic • Data used from January 18 to April 14 • Using two surface antennas • Galactic noise clearly seen over thermal (~ -130 dbW) Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  13. This season’s on ice achievementsDeep pulsers on IceCube strings • 3 high voltage calibration Tx installed on IceCube strings at ~1.5 and 2.5km • Deep (2450m) pulser seen by all antennas in the ARA testbed! • Testbed is a horizontal distance of ~1.6 km away- total distance 3.2 km. • Points to an attenuation length of >700m (analysis ongoing). • Time delays between different antennas used to estimate T resolution. mV σtime=97 ps ns Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  14. This season’s on ice achievements Challenges in constructing and operating a large array • Tested two different drills: • - Drilling speed • - Depth • - Hole diameter, smoothness • - Logistics • Installed several models of wind turbines • - Measuring and comparing wind speed, power yield. • -Weather effects to be evaluated next summer Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  15. Summary • On going analyses with IceCube radio extensions, • A collaboration has been formed to build an englacial array large enough to detect cosmogenic neutrinos • An array concept has been proposed. The first phase funded. • Fine tuning of instrumentation and detector spacing to be optimized during the development phase • Successful first South-Pole season • Facing several challenges in building and operating a large scale detector such as power distributions and fast drilling. • Work has commenced in preparation for the next season • Eventual large scale array will determine cosmogenic neutrino flux and tackle associated long standing questions of cosmic rays. Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  16. Backup slides Hagar Landsman ARA Spring 2011, Madison

  17. This season’s on ice achievementsDeep pulsers on IceCube strings • Blind spots due to ray tracing. The deeper we get the larger the horizon is. • This was the last access to deep holes. • 3 high voltage calibration Tx installed on IceCube strings at ~1.5 and 2.5km • Azimuthally symmetric bicone antenna -eliminates systematics from cable • shadowing effects • Goals: radio glaciology and calibration Receiver Transmitter Horizon for 3 different receiver depths Ray traces 200m Ray traces 1500m 0 0 0 1000m 1 200m 1 0.6 Depth [km] Depth [km] Depth [km] 20 m 2 2 1.2 3 3 1.8 0 1 2 3 4 0 1 2 3 4 0 0.5 1 1.5 2 2.5 Distance [km] Distance [km] Horizon [km] 17 Hagar Landsman ARA Spring 2011, Madison

  18. Ray Propagation Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  19. ARA expected performance Effective volume 1000 Ongoing simulation studies to optimize detector geometry, and make the best use of the 2.5km ice target. 100 Effective volume [km3sr] 10 17 18 19 20 Neutrino Energy [eV] Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  20. The Game Plan Establish cosmogenic neutrino fluxes Resolve Energy Spectrum Neutrino direction Reconstruction Flavor analysis Particle physics • Small set of well established events. • Coarse energy reco • Energy reconstruction by denser sampling of each event • Angular resolution of less than 0.1 rad ~10 Events/year ~1000 Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  21. ARA expected performance detector sensitivities How strong should a source be, for it to be detected by a detector IceCube (3 years) Auger Tau (3 years) GZK RICE 2006 ARA (3 years) Pure Iron UHECR ANITA (3 flights) Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  22. ARA expected performance Reconstruction • Vertex reconstruction : • Where in the ice did the Neutrino interact? • Using timing information from different antennas. • Distance to vertex (for calorimetry) • Location of Vertex (Background rejection • Neutrino Direction and Energy: • Where in space did the Neutrino come from? • Combining amplitude and polarization information with Cherenkov cone models. • ARA is not optimized for this. Simulated Angular resolution: ~6° Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  23. Phase 1: 3 years plan • Large array challenges: • Power source • Power and communication distribution • Drilling (size, depth, drilling time) • EMI • 2010-2011 • Install testbed • EMI survey away from the station • Test ice properties • Begin testing station prototypes • Calibration activities • Install 3 deep RF Pulsers • Conduct Drilling tests • Install 3 Wind turbines for testing • 2011-2012 • Install ARA in ice station • Install Power/comm hub • 2012-2013 • Install ARA in ice station • Install autonomous Power/comm hub Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  24. Finding the right drill Why it is a big deal for us • Detector design: • Hole diameter impacts antennas design • Wet/dry hole • Depth possibilities: • Shadowing effect  Deeper is better • Ice Temperature  Shallower is better • Logistics: • Drill will have to be moved several times a season • Short setup and drilling time • Simple operation • Cost & schedule: • Use existing technologies. • Keep it fast, save and simple Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  25. This season’s on ice achievementsDrill Test 1 : Rapid Air Movement • Cutter head drill hole-shavings extracted using compressed air • Extra compressors required at SP altitude • Lots of cargo to get it to the Pole • Dry, 4 inch hole • Deepest holes achieved: ~60 m in less than 1 hour. • Limited by air pressure leakage through the firn Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  26. This season’s on ice achievementsDrill Test 2 : Hot water drill • Carried on three sleds pulled by tractor • 0.5 – 1m per minute ( 200m in ~1/2 day ) • 6” hole • Wet hole- must be pumped out or electronic made watertight • Deepest hole drilled ~160 m Drill in Operation ARA hot water drill sleds Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  27. This season’s on ice achievementsWind Turbines • Three different turbines were installed. • Measuring and comparing wind speed, power yield. • Weather effects to be evaluated next summer. Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  28. ARA’s prototype antennas • Antennas design: • 150-850 MHz • Designed to fit in 15cm holes • Azimuthal symmetric • Cables pass through antenna. No shadowing. 32

  29. Ice Properties: Attenuation length • Depends on ice temperature. Colder ice at the top. • Reflection Studies (2004) (Down to bedrock, 200-700MHz): “normalize” average attenuation according to temperature profile. Besson et al. J.Glaciology, 51,173,231,2005 • 2 on going “point to point” analyses using NARC/RICE and the new deep pulse. 34 Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  30. Askaryan effect Hadronic EM Neutrino interact in ice  showers  Many e-,e+, g Vast majority of shower particles are in the low E regime dominates by EM interaction with matter  Interact with matter  Excess of electrons  Cherenkov radiation Less Positrons: Positron in shower annihilate with electrons in matter e+ +e- gg Positron in shower Bhabha scattered on electrons in matter e+e-  e+e- More electrons: Gammas in shower Compton scattered on electron in matter e- + g  e- +g Coherent for wavelength larger than shower dimensions Moliere Radius in Ice ~ 10 cm: This is a characteristic transverse dimension of EM showers. <<RMoliere (optical), random phases P N >>RMoliere (RF), coherent  P N2 Charge asymmetry: 20%-30% more electrons than positrons. 35 Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  31. Salt Ice Typical pulse profile Strong <1ns pulse 200 V/m Simulated curve normalized to experimental results Measurements of the Askaryan effect • Were preformed at SLAC (Saltzberg, Gorham et al. 2000-2006) on variety of mediums (sand, salt, ice) • 3 Gev electrons are dumped into target and produce EM showers. • Array of antennas surrounding the target Measures the RF output • Results: • RF pulses were correlated with presence of shower • Expected shower profiled verified D.Salzberg, P. Gorham et al. • Expected polarization verified (100% linear) • Coherence verified. • New Results, for ANITA calibration – in Ice 36 Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  32. Ice Properties: Index Of Refraction 1.77 • RICE Measurements (2004, Down to 150 m, 200MHz-1GHz) • Ice Core Measurements (…-1983, down to 237 meters) Kravchenko et al. J.Glaciology, 50,171,2004 37 Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  33. Ray tracing from pulser to SATRA Top antenna -5m surface Reflected rays Bottom antenna -35m Direct rays Depth [m] Source at -250m Measured time differences: Time differences between direct rays And between direct and reflected rays can be calculated XY separation [m] Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  34. SATRA Average envelope WFs For In Ice Pulser events Hole 8, Bottom Hole 8, Top Hole 9, Bottom Hole 9, Top Hole 16, Bottom Hole 16, Top ~44 bins = ~139 ns Simulated results=137 ns Simulated results=14 ns Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

  35. n_shallow n_c Based on set of hit time differences between antennas and between primary and secondary hits on the same antenna, a limit on the index of refraction model can be obtained. Systematics taken into account: n_deep, Geometry, timing resolution, WF features Hagar Landsman IceCube RF extension and ARA APS 2011, Anaheim,CA

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