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Tribute to ATLAS

Tribute to ATLAS. IceCube . Built upon success of AMANDA Up to 86 strings of 60 digital optical modules(DOM) 1450-2450 m deep 17 m spacing between DOMs 125 m triangle grid Each DOM is an autonomous data collection unit IceTop air shower array 162 surface water tanks

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Tribute to ATLAS

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  1. Tribute to ATLAS IceCube • Built upon success of AMANDA • Up to 86strings of 60 digital optical modules(DOM) • 1450-2450 m deep • 17 m spacing between DOMs • 125 m triangle grid • Each DOM is an autonomous data collection unit • IceTop air shower array • 162surface water tanks • Each contains 2 DOMs 25 m 45 m

  2. Tribute to IceCube

  3. ARAThe Askaryan Radio Array A new instrument for the detection of highest energy neutrinos. Hagar Landsman, UW Madison

  4. Highest energy neutrinos….Why ? • There is a high energy universe out there we know very little about! • HE Neutrinos are expected to be produced together with photons and protons through pions decay. • Neutrinos add complimentary information to gamma astronomy • With neutrinos we can look further away • Cosmic rays with energies of more than 1020eV were observed. • Their source, or acceleration mechanism are unknown. • Sufficiently energetic Cosmic rays interact on photon background and loose energy • No energetic CR from large distances (>50MPc) • Flux of neutrino : “Guaranteed source” p + g  D * n + p venmne ve p+ g D * n + p venm ne ve p Hagar Landsman ARA Spring 2011, Madison

  5. Why not Build a Larger IceCube?IceCube can detect cosmogenic neutrinos, but not enough of them … • Current IceCube configuration: • Effective area: • Yields less than 1 cosmogenic event/year • Making IceCube bigger is an option: • Some geometry optimization is possible, though: • Still need dense array scattering • Still need deep holes for better ice • Any additional string will cost ~1M $* Simulated 9EeV event IceCube (80 strings) More than 60% of DOMs triggered A larger detector requires a more efficient and less costly technology. *Rough estimation, Real cost will likely be higher Hagar Landsman ARA Spring 2011, Madison

  6. Solution: Use Cherenkov photons in RF • Longer attenuation length in ice larger spacing  less hardware • Less scattering for RF In ice. • Cherenkov radiation pattern is preserved • Don’t need many hits to resolve direction • No need to drill wide holes • Better ice at the top. No need to drill deep. • Antennas are more robust than PMTs. • The isolated South Pole is RF quite and • Any EMI activity is regulated • Deep ice (2.5km) contributes to effective volume • It is easy to detect RF Gurgen Askaryan (1928-1997) Remember: Less photons are emitted in longer wave length. Smaller signal in the radio frequencies…. But for high energy cascades this RF radiation becomes coherence and enhanced “Askaryan effect” PavelAlekseyevich Cherenkov (1904-1990) Hagar Landsman ARA Spring 2011, Madison

  7. Askaryan Effect Heritage RICE Radio Ice Cerenkov Experiment Array of single dipole antennas deployed between 100 and 300m near the South Pole, covered an area of 200m x 200m. (mostly in AMANDA holes) Used digital oscilloscope on surface for data acquisition IceCube Radio Co deployed with IceCube at 30m, 350m and 1400 m. Full in ice digitization. The Askaryan effect Was measured in a special SLAC experiment . Extensive simulation of the radiation cone exist, and predictions are in agreement with the measurement. ANITA ANtarctic Impulsive Transient Antenna : surveys the ice cap from high altitude for RF refracted out of the ice (~40 km height of fly, ~1.1M km2 field of view) Hagar Landsman ARA Spring 2011, Madison

  8. South Pole Heritage Obviously the people involved know what they are doing ! Hagar Landsman ARA Spring 2011, Madison

  9. 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 10 Hagar Landsman ARA Spring 2011, Madison

  10. ARA Concept • 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 11 Hagar Landsman ARA Spring 2011, Madison

  11. 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

  12. 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 ARA Spring 2011, Madison

  13. 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) 14 Hagar Landsman ARA Spring 2011, Madison

  14. 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° 15 Hagar Landsman ARA Spring 2011, Madison

  15. 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. Growing collaboration. Strong interests from others (Australia, Israel) Regular collaboration meetings (and phone calls) http://ara.physics.wisc.edu 16 Hagar Landsman ARA Spring 2011, Madison

  16. 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 17 Hagar Landsman ARA Spring 2011, Madison

  17. 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 18 Hagar Landsman ARA Spring 2011, Madison

  18. This season’s on ice achievementsARA Test Bed – Trigger rates Off season 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 change • Weather balloon launches CW clearly seen 19 Hagar Landsman ARA Spring 2011, Madison

  19. This season’s on ice achievementsARA Test Bed – Galactic center Larissa Paul Noise measured on the surface antennas Ch 2 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) 20 Hagar Landsman ARA Spring 2011, Madison

  20. 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] 21 Hagar Landsman ARA Spring 2011, Madison

  21. This season’s on ice achievementsDeep pulsers on IceCube strings • 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 mV ns ns σtime=97 ps mV ns 22 Hagar Landsman ARA Spring 2011, Madison

  22. 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 23 Hagar Landsman ARA Spring 2011, Madison

  23. 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 24 Hagar Landsman ARA Spring 2011, Madison

  24. 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 25 Hagar Landsman ARA Spring 2011, Madison

  25. 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. 26 Hagar Landsman ARA Spring 2011, Madison

  26. Summary • 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. Many thanks to those who drilled, built, wrote, trenched, dag, checked, deployed, debugged, shoveled, drove, tested, carried, installed, submitted and resubmitted. 27 Hagar Landsman ARA Spring 2011, Madison

  27. Backup 28

  28. This means two things: No cosmic rays from proton above 1020 eV As a by-product – neutrino flux Flux above the cutoff may indicate: Heavier composition of UHE CR Source of the UHE CR is closer Relativity and SM are not right in these energies. Measurement error – energy calibration GZK neutrinos Guaranteed source! Propagating Cosmic rays interact on photon background and loose energy. Threshold Microwave background radiation Ep>1019eV

  29. Channel 15 30Mhz-300 Mhz Channel 2 100Mhz-1000 Mhz

  30. Huge solar falre on February 13, 2011Day of year 44 Channel 15 30Mhz-300 Mhz Channel 2 100Mhz-1000 Mhz

  31. ch2 ch8 ch10 greenbank Hagar Landsman

  32. Higher frequencies Lower frequencies Cherenkov cone Event Reconstruction Askaryan radiation cone zhs 1992 Alvarez-Muniz, Romero-Wolf, Zas 2010

  33. Event Reconstruction Simulation: 1 PeV e induced shower in time domain. 5 degrees off the cone On cone Alvarez-Muniz, Romero-Wolf, Zas 2010 Use precise timing info to determine vertex location. Use polarization and amplitude to estimate energy and direction.

  34. Antennas design: • 150-850 MHz • Designed to fit in 15cm holes • Azimuthal symmetric • Cables pass through antenna. No shadowing. 35

  35. 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.

  36. 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.

  37. 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

  38. Deep pulser installation

  39. 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

  40. 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]

  41. 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

  42. Askaryan effect is for real Extensive theoretical and computational modeling work exists. Verified in SLAC measurement Agreement between both

  43. 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

  44. Cosmic Ray CompositionProtons? Heavy Nuclei? Photons? January 2011 Shower maxima – the point in which the shower stops developing. Units of density x distance = g/cm^2 Using Shower development measurement (Xmax)and modeling  Pure EM showers: Pair production till shower attenuates. Hadronic showers: Many Secondaries– shower develops faster. Higher Xmas.  Nuclei (E,Z) Superposition of Z showers with energy E/Z  Smaller RMS on Xmas

  45. Cosmic Ray compositionprotons, heavi nuclei, photons, neutrinos?  Pure EM showers Pair production till shower attenuates. Hadronic showers Muons, Many secondaries. Xmax higher.  Nuclei (E,Z) Superposition of Z showers with energy E/Z  Smaller RMS on Xmas Hadronic shower • Many secondaries • Muons

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