“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Future methods::Radio Hagar Landsman University of Wisconsin, Madison

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Outline In Ice: Neutrino astronomy  “AURA” - RF enhanced IceCube –2 clusters In the Ice –taking data [ ] –2-3 New clusters to be deployed next season[ ] Goal: Noise levels measurement; Coincidence with IceCube/IceTop;  Firn and EMI tests [ ] Goal: How shallow can we get? More data on firn. Surface detector: CR and astronomy  Surface survey and antennas designs Goal: Noise measurement; Coincidence with IceTop; Future hardware development  Exploring new technologies for next generation detectors –IceCube High energy extension [ ] Go hybrid: Optical, Acoustic, Radio. –Standalone array [2011….] Goal: Sub GZK detector; Enhance IceCube HE sensitivity

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Use IceCube’s resources: holes, comm. and power Each Cluster contains: –Digital Radio Module (DRM) – Electronics –4 Antennas –1 Antenna Calibration Unit (ACU) Signal conditioning and amplification happen at the front end Signal is digitized and triggers formed in DRM A cluster uses standard IceCube sphere, DOM main board and surface cable lines. surface junction box surface junction box Counting house AURA Radio Cluster Askaryan Under ice Radio Array

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; time Down going event signature

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Down going event candidate time

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; time Up going event signature Antenna 1 Antenna 2 Antenna 3 Antenna 4 time Digital Radio Module

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; time Up going event signature Antenna 1 Antenna 2 Antenna 3 Antenna 4 time Digital Radio Module

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Muon bundle Energy dependence of air showers signals Air shower in 125m distance with 45 inclination angle simulated with Reas2 Jan Auffenberg Based on south pole RF surface survey 1 MHz-500MHz (red curve) RF Content for Muon bundles can get above background coincidences with IceCube are possible

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; 3 clusters are fully integrated – To be cold tested in PSL and further characterize in KU. Tests include: –Gain and power calibration –EMI noise estimation –Response to sharp pulses –Vertexing Changes from previous year design include : – Low frequency channels (down to 100MHz) –Smarter and stronger ACU –Decrease distances between antennas –Boards layout, internal power supply New clusters

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Future detector design Some considerations: Frequency range and band width. Antennas type Data type: Full digitized WF Scope Transient array Geometry (depth and spacing): Space detectors Shadowing effect  Deeper is better Ice Temperature  Shallower is better Drilling cost and time– Deep=expensive Hole diameter can limits design of antennas Wet/dry hole Unique signature of Askaryan: short pulse, linearly polarized - Capture polarization? - Low freq has wider energy spread but more noise - Narrow holes effect design

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Future detector design Some considerations: Frequency range and band width. Antennas type Data type: Full digitized Wave Form Scope Transient array Geometry (depth and spacing): Space detectors Shadowing effect  Deeper is better Ice Temperature  Shallower is better Drilling cost and time– Deep=expensive Hole diameter can limits design of antennas Wet/dry hole Full WFs give good timing and frequency content, But require more sophisticated DAQ and electronics (power, noise) and larger data volumes

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Future detector design Some considerations: Frequency range and band width. Antennas type Data type: Full digitized WF Transient array Scope Geometry (depth and spacing): Space detectors (outer ring better as ring, and not as pile) Shadowing effect  Deeper is better Ice Temperature  Shallower is better Drilling cost and time– Deep=expensive Hole diameter can limits design of antennas Wet/dry hole Denser Shallow holes  Spaced deep holes

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Transient sensor array Kael Hanson Perry Sandstorm Many “simple” sensors to provide a snap shot of an Askaryan pulse. Wide dynamic range, low power, simple output

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; IceRay: 50 km 2 Baseline Studies (the “AMANDA” of radio) Higher density, shallow (50m) vs. sparse, deep (200m  Estimate to get 3-9 events/year using “Standard fluxes”  events/year with IceCube coinc.

Three-prong hybrid air shower studies (1) IceTop, (2) Muons in deep ice, (3) Radio Proposal submitted to European funding agencies Options for IceTop Radio Extension Expansion of surface array   Veto for UHE neutrino detection InIce Infill surface array   Hybrid CR compositon

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Seasonal tests (and longer) Anthropogenic vs. ambient noise far from station Surface Field studies coordinated with in-ice radio 4 arm monopole antennas : Long term variability, transient noise, correlation with IceTop In Ice EMI noise away from the station (spresso) RF properties of the firn using firn holes Test Antennas in their natural environment Calibration of in ice clusters

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; EMI test bed -EMI monitoring ~2km out of the station. -Ground screen above array to block galactic, solar, aircraft and surface RF noise MHz - Hardware exist -Independent proposal submitted -Also: checking option to use firn holes near and away station to study firn and EMI emission (not a part of IceRay).

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Summary RF South Pole activity is on going en route to a GZK detector – deep and surface. 2 in ice AURA clusters are taking data: Working on event reconstruction, timing and noise studies. Preparing for 3 deployment next season with a stronger calibration unit. Further EMI surveys up to 1 GHz and Firn studies will be helpful for future designs. Surface activity includes EMI surveys and coinc with IceTop Towards larger scale detector: Checking several detection schemes

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Backup

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Why EeV neutrinos ? –GZK cutoff No Cosmic rays above ~10 20 eV High energy neutrinos –Study of energetic and distant objects (Photons attenuation length decrease with energy) –Study highest energy neutrino interaction –Point source –Exotic sources –The unknown The predicted flux of GZK neutrinos is no more than 1 per km 2 per day. ….but only 1/500 will interact in ice. IceCube will measure ~1 event per year. We need a 1000km 3 sr to allow: Statistics, Event reconstruction ability, flavor id

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Waiting to be deployed Antennas Pressure vessels DRM Antenna cables

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; RF signal Antennas: Broad band dipole antennas Centered at 400 MHz Front end electronics contains: 450 MHz Notch filter 200 MHz High pass filter ~50dB amplifiers (+20 dB in DRM) LABRADOR digitizer: Each antenna is sampled using two 1GHz channels to a total of 512 samples per 256 ns (2 GSPS). A dipole antenna A 5-years old

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Deployment Hole 57: “scissors” 2 nd deployment, Shallow ~-300 m 4 Receivers, 1 Transmitters Hole 47: “paper” 3 rd Deployment, Deep 1 Transmitter Hole 78 :“rock” 1 st deployment, Deep ~-1300 m 4 Receivers, 1Transmitters

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Inter-cluster timing Pat Kenny Time difference in 0.5 ns bins Most Down going events pointed back to the Operations Sector (red) Timing resolution of 2 ns within a cluster

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Why Radio? Askaryan effect Coherent Cherenkov RF emission of from cascades. Radio emission exceeds optical radiation at ~10 PeV Completely dominant at EeV energies. Process is coherent  Quadratic rise of power with cascade energy A Less costly alternative Larger spacing between modules (Large Absorption length) Shallower holes Narrower holes Good experience Experimental measurement of RF enhanced signal from showers Technology used for : RICE, ANITA, and other optical Radio Ice, no bubbles ( km) Ice, bubbles (0.9 km) Water (Baikal 1km) Effective Volume per Module (Km 3 ) Energy (eV) Astro-ph/ P.B.Price 1995

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Inter string Results Coinc with ice top 10m telescope New station MAPO ICL 1100 m 375 m 6.8 /pm 0.13 usec Also looking for coincidences with Ice Top 10m telescope

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Background and signal levels

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; RF Signal Nyquist: V rms = (4K b TR  F) 1/2 –V=3 mVolts= RMS of 3-5 bins Environment background: Average In Ice background up to 1 GHz: -86 dbm = 2.5 E-9 mW After ~70 db amplification: –16 dbm  35mV RMS  30 DAC counts rms (for 2007) – 16 dbm  35mV RMS  60 DAC counts rms (for 2009) Maximum signal: Dynamic Range=1200 counts –  1320 mV RMS  15 dbm  -55dbm = 3E-6 mW before amps (07) –  720 mV RMS  10 dbm  -60 dbm= 1E-6 mW before amps (09) 2007 cluster mV/DAC is ~ cluster mV/DAC is ~0.6

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Suitability of IceCube environment Channel and cluster trigger rates were compared when IceCube/AMANDA were idle and taking data. IC + AMANDA on AMANDA off IC + AMANDA off band A (Lowest freq.) band D (Highest freq.) band C (High freq.) band B (Low freq.) Channel 1 Scaler rate vs. Discriminator value Noise from IC/AMANDA is enhanced in lower frequency on a given channel/band. Combined trigger reject most of this noise. Measurement only down to ~200 MHz

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Existing external sources RICE –CW – observed and measured by shallow cluster –Pulse – not observed, too weak. Another RICE test is scheduled. Other cluster’s ACU –ACU too weak – Development of stronger ACU Same ACU –Shows signal elongation (we’ll get back to this point) xy Seperatio n Shallo w -300m Deep -1400m Pinger m RICE m shallow375 m125 m150 m Deep375 m400 m500 m Xx add ray tracing xx

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Gain Calibration DRM 1: Full Cluster DRM only

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Is the DRM quiet Screen chamber was built inside the old dfl -174 dbm/Hz thermal floor translates into -108 dbm/4Mhz. DRM1 is watching DRM2: Outside screen room Low freq Freq (4MHz) Average FFT Spectrum:Gain corrected Average FFT Spectrum: Outside screen room Ch 1 Ch 2 Ch 3 Ch 4 Ch 1 Ch 2 Ch 3 Ch 4

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Confirmed Response to a sharp pulse  =

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Cluster was spaced in the PSL production hall. Antennas ~3 m high. Confirmed vertexing ability

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Noise levels – per freq bin

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08;

To antenna To antenna To antenna To surface To Calibration unit To antenna Shielding separates noisy components 6 Penetrators : 4 Antennas 1 Surface cable 1 Calibration unit TRACR Board Trigger Reduction and Comm for Radio Data processing, reduction, interface to MB ROBUST Board ReadOut Board UHF Sampling and Triggering Digitizer card SHORT Boards Surf High Occupancy RF Trigger Trigger banding MB (Mainboard) Communication, timing, connection to IC DAQ infrastructure, Digital Radio Module (DRM) Digital Optical Module (DOM)

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Triggering Were Enough Antennas hit? Band 1Band 2Band 3Band 4 Were Enough bands hit? Band 1Band 2Band 3Band 4 Were Enough bands hit? Band 1Band 2Band 3Band 4 Were Enough bands hit? Band 1Band 2Band 3Band 4 Were Enough bands hit? Antenna1 Antenna2Antenna3Antenna4 Band a: ~ MHz Band b: ~ MHz Band c: ~ MHz Band d: ~ MHz 16 combinations of triggers:

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Solid- “Real Trigger” Dashed -“Forced trigger”

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Antennas simulation using Finite-Difference Time-Domain Analysis 90 Deg 80 Deg 70 Deg 60 Deg 50 Deg 40 Deg 30 Deg 20 Deg 10 Deg θ AURA Antenna simulated response to a 1ns pulse 1v/m Andrew Laundrie 3 meters Antenna response Andrew Laundrie As the source pulse becomes shorter relative to the electrical length of the antenna, the resulting waveform has more information about the angle of arrival Longer antenna may Also working on: Simulated Cherenkov radiation Antenna for transmitting Cherenkov-like radiation (useful for testing hardware)

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Vector Antennas Askaryan signal is Linearly polarized This compact antenna can Capture Full Polarization information Compact, broadband, rugged, easy to construct, affordable Last development stages Testing to begin soon Jan Bergman

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Acceptance and Event Rates Initial phase achieves 3-9 ev/year for “standard” fluxes Final phase: ~100 ev/year

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Frequency Range Ice is better at low frequency (< 500 MHz) Solid angle also better at low freq. SNR goes as sqrt(bandwidth) Go low freq., high bandwidth: MHz

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; “Golden” Hybrid Events Triggering both IceRay and IceCube: rates are low, but extremely valuable for calibration High-energy extension (IceCube+ above) with 1.5km ring helps a lot Sub-threshold cross- triggering can also help IceRay-36 / shallow

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Neutrino interact in ice  showers Charge asymmetry: 20%-30% more electrons than positrons. Moliere Radius in Ice ~ 10 cm: This is a characteristic transverse dimension of EM showers. <<R Moliere (optical), random phases  P  N >>R Moliere (RF), coherent  P  N 2 Hadronic (initiated by all flavors) EM (initiated by an electron, from e ) Askaryan effect Vast majority of shower particles are in the low E regime dominates by EM interaction with matter Less Positrons: Positron in shower annihilate with electrons in matter e + +e -   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 - +   e - +   Many e -,e +,   Interact with matter  Excess of electrons  Cherenkov radiation  Coherent for wavelength larger than shower dimensions

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; As the energy increases, the multiplicity of the shower increases and the charge asymmetry increases.  As the energy increases, mean free path of electrons is larger then atomic spacing (~1 PeV) (LPM effect).  Cross section for pair production and bremsstrahlung decreases  longer, lower multiplicity showers The Neutrino Energy threshold for LPM is different for Hadronic and for EM showers  Large multiplicity of hadronic showers. Showers from EeV hadrons have high multiplicity ~ particles.  Photons from short lived hadrons  Very few E>100 EeV neutrinos that initiate Hadronic showers will have LPM LPM effect Landau- Pomeranchuk- Migdal  In high energy, Hadronic showers dominate  Some flavor identification ability

“Radio detection”, Hagar Landsman; IceCube Science Advisory Committee May 5, 08; Askaryan Signal Cherenkov angle=55.8 o Electric Field angular distributionElectric Field frequency spectrum Astro-ph/ Alvarez-Muniz, Vazquez, Zas 1999