DOCSLIB.ORG

The Cosmic-Ray Air-Shower Signal in Askaryan Radio Detectors

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Cosmic-Ray Air-Shower Signal in Askaryan Radio Detectors The cosmic-ray air-shower signal in Askaryan radio detectors Krijn D. de Vriesa, Stijn Buitinka, Nick van Eijndhovena, Thomas Meuresb, Aongus O´ Murchadhab, Olaf Scholtena,c aVrije Universiteit Brussel, Dienst ELEM, B-1050 Brussels, Belgium bUniversit´eLibre de Bruxelles, Department of Physics, B-1050 Brussels, Belgium cUniversity Groningen, KVI Center for Advanced Radiation Technology,Groningen, The Netherlands Abstract We discuss the radio emission from high-energy cosmic-ray induced air showers hitting Earth's surface before the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino flux in ice. The in-air emission, the in-ice emission, as well as a new component, the coherent transition radiation when the particle bunch crosses the air-ice boundary, are included in the calculations. Key words: Cosmic rays, Neutrinos, Radio detection, Coherent Transition Radiation, Askaryan radiation 1. Introduction needed. Due to its long attenuation length, the induced radio signal is an excellent means to detect these GZK We calculate the radio emission from cosmic-ray-induced neutrinos. This has led to the development of several air showers as a possible (background) signal for the Askaryan radio-detection experiments [1-6,26-30]. Nevertheless, the radio-detection experiments currently operating at Antarc- highest-energy neutrinos detected so-far are those observed tica [1, 2, 3]. A high-energy neutrino interacting in a recently by the IceCube collaboration [31] and have ener- medium like (moon)-rock, ice, or air will induce a high- gies up to several PeV, just below the energies expected energy particle cascade. In 1962 Askaryan predicted that from the GZK neutrino flux. during the development of such a cascade a net negative In this article we calculate the radio emission from charge excess arises mainly due to Compton scattering [4]. cosmic-ray-induced air showers as a possible (background) This net excess charge by itself will induce a radio signal signal for the Askaryan radio-detection experiments cur- that can be used to measure the original neutrino. This rently operating at Antarctica [1, 2, 3]. Besides the emis- Askaryan radio emission [4, 5, 6] has been confirmed ex- sion during the cascade development also transition radi- perimentally at SLAC [7], and more recently the Askaryan ation should be expected when the cosmic ray air shower effect was also confirmed in nature by the radio emission hits Earth's surface [32, 33]. It follows that the induced from cosmic-ray induced air showers [8, 9, 10]. emission is very hard to distinguish from the direct Askaryan For high-energy cosmic-ray air showers, along with the emission from a high-energy neutrino induced cascade in Askaryan emission, there is another emission mechanism a dense medium such as ice. due to a net transverse current that is induced in the shower front by Earth's magnetic field [11-14]. Recently the radio emission from cosmic-ray air showers has been 2. Radio emission from a particle cascade measured in great detail by the LOFAR collaboration [10, 15, 16], confirming the predictions from several indepen- We start from the Li´enard-Wiechert potentials for a dent radio emission models [17-20]. point-like four current from classical electrodynamics and Most Askaryan radio detectors [1-3,21-23] search for closely follow the macroscopic MGMR [34] and EVA [20] models. Both models were developed to describe the ra- arXiv:1503.02808v2 [astro-ph.HE] 25 Nov 2015 so-called GZK neutrinos that are expected from the in- dio emission from cosmic-ray-induced air showers. The teraction of ultra-high-energy cosmic-ray protons with the µ cosmic microwave background [24, 25]. The expected GZK Li´enard-Wiechert potentials for a point charge, APL(t; ~x), neutrinos are extremely energetic with energies in the EeV as seen by an observer positioned at ~x at an observer time t range, while the flux at these energies is expected to fall be- are obtained directly from Maxwell's equations after fixing low one neutrino interaction per cubic kilometer of ice per the Lorenz gauge [35], year. Therefore, to detect these neutrinos an extremely µ µ 1 J large detection volume, even larger than the cubic kilo- A (t; ~x) = : (1) PL 4π jDj meter currently covered by the IceCube experiment, is 0 ret The point-like current is defined by J µ = eV µ, where e µ Email address: [email protected] (Krijn D. de Vries) is the charge, and V is the four-velocity for a particle at Preprint submitted to Elsevier April 9, 2018 ~ ξ(tr) where the retarded emission time is denoted by tr. where the distance di, the distance covered by the emission The denominator of the vector potential, D, is the retarded in layer i, is obtained by using a ray-tracing procedure four-distance. For an extended current with longitudinal based on Snell's law. Following [36], the retarded distance dimension h and lateral dimensions ~r, the vector potential for a signal traveling through different media is given by, has to be convolved with the charge distribution given by dt the weight function w(~r; h), D = L : (5) dtr Z µ µ 1 2 J w(~r; h) A (t; ~x) = dh d r ; (2) In this work the index of refraction is assumed to be in- 4π jDj 0 ret dependent of frequency within the radio frequency range where the vector potential has to be evaluated at the re- starting from a few MHz, up to several GHz. In the simpli- tarded emission time tr. The corresponding geometry is fied situation where the signal travels through a medium with constant index of refraction n, the retarded distance can be written in the more common form, x/ y− plane Cascade direction z D = nR(1 − nβ cos(θ)) ; (6) Observer position: where θ denotes the opening angle between the line of sight (x=0, y=0, z=0) (x , y ,z=0) from the emission point to the observer and the direction of movement of the emitting charge. d= (x−r )2 +( y−r )2 Charge cloud: √ x y ⃗ξ=( =− ) 0,0, z ct r 2.1. Cherenkov effects for a single electron V μ=(1,0,0,−β) 2 2 For a single electron moving at a highly relativistic R=√(−ct r +h) +d velocity β~ = ~v=c ≈ 1 along the z-axis (by definition), n=n h 2 the current is given by J µ = e (1; 0; 0; −β). The electric z=z b n=n1 r Charge position: field is now obtained directly from the Li´enard-Wiechert (x−rx , y−r y , z=−ct r +h) potentials through, dA0 dAi Ei(t; ~x) = − − ; (7) dxi dct Figure 1: The geometry used to calculate the radiation where i = x; y gives the polarization of the field in the i emitted from a charge cloud crossing a boundary at z = transverse direction, and x denotes the observer position in the transverse plane (x1 = x; x2 = y). For the moment zb. The observer is positioned at an impact parameter p 2 2 we will ignore the electric field in the longitudinal direction d = (x − rx) + (y − ry) . and, since Ai / J i = 0 for i = 1; 2 (there is no transverse current), we only have to consider the spatial derivative of denoted in Fig. 1. We consider an observer positioned at the scalar potential. The electric field in the longitudinal an impact parameter d = p(x − r )2 + (y − r )2 perpen- x y direction will in general be small and can easily be calcu- dicular to the charge track, where r , and r denote the x y lated following the gauge condition ~k · ~ = 0, where ~k is lateral position of the considered charge within the charge the momentum vector of the photon and ~ the polarization. cloud. Defining the element in the plane of the observer Hence the photon cannot be polarized along its direction perpendicular to the charge-track as z = 0, we can define of motion. Starting at the zeroth component of the vector the time at which the front of the charge cloud crosses this potential, the spatial derivative can be evaluated by, plane to be t = 0. Using these definitions the position of the charge along the track is now given by z = −ctr + h. dA0 @ = A0; (8) Fixing the geometry, the vector potential can now be dxi @xi evaluated. The retarded emission time is obtained from the light-cone condition with respect to the optical path which corresponds to the radiation from a net charge mov- length L, ing through the medium. For a relativistic electron (β ≈ 1) moving in a medium with a refractive index n > 1 this c(t − tr) = L; (3) term becomes, from which the relation between the observer time and the i @ 0 Est(t; ~x) = − A emission time, tr(t), can be obtained. It should be noted @xi that tr is a negative quantity. For a medium consisting −e (1 − n2)xi out of m layers with different index of refraction n , the = 3 : (9) i 4π0 jDj optical path length can be defined by m Where the label 'st', denotes that the field is due to a X highly relativistic non time-varying steady charge. The L = nidi; (4) i=1 emission shows a radial polarization direction and vanishes 2 linearly with the distance of the observer to the shower evaluated as, core. This component of the electric field is suppressed by @t @ the factor 1 − n2, which vanishes in vacuum.
Load more

Recommended publications
  • Experimental Calibration of the ARA Radio Neutrino Telescope with an Electron Beam In
    Experimental calibration of the ARA radio neutrino telescope with an electron beam in ice PoS(ICRC2015)1136 R. Gaïora, A. Ishiharaa, T. Kuwabaraa, K. Mase∗a, M. Relicha, S. Ueyamaa S. Yoshidaa for the ARA collaboration, M. Fukushimab, D. Ikedab, J. N. Matthewsc, H. Sagawab, T. Shibatad, B. K. Shine and G. B. Thomsonc a Department of Physics, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan b ICRR, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8522, Japan c Physics And Astronomy, University of Utah, 201 South, Salt Lake City, UT 84112, U.S. d High Energy Accelerator Research Organization (KEK), 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki, 319-1195, Japan e Department of Physics, Hanyang University, 222 Wangsimni-ro Seongdung-gu Seoul, 133-791, Korea ∗E-mail: [email protected] Askaryan Radio Array (ARA) is being built at the South Pole, aiming to observe high energy cosmogenic neutrinos above 10 PeV. The ARA detector aims to observe the radio emissions from the excess charge in a particle shower induced by a neutrino interaction. Such a radio emission was first predicted by Askaryan in 1962 and experimentally confirmed by Saltzberg et al. using the SLAC accelerator in 2000. We also performed an experiment of the ARA calibration with the Telescope Array Electron Light Source (ARAcalTA) to verify the understanding of the Askaryan radiation and the detector response used in the ARA experiment. In the ARAcalTA experiment, we irradiated an ice target with 40 MeV electron beams using the Telescope Array Electron Light Source (TA ELS) located in a radio quiet open-air environment of the Utah desert.
    [Show full text]
  • Radiowave Detection of Ultra-High Energy Neutrinos and Cosmic Rays
    Prog. Theor. Exp. Phys. 2017, 00000 (53 pages) DOI: 10.1093=ptep/0000000000 Radiowave Detection of Ultra-High Energy Neutrinos and Cosmic Rays Tim Huege and Dave Besson Karlsruhe Institute of Technology, Karlsruhe 76021, Germany ∗E-mail: [email protected] KU Physics Dept., 1082 Malott Hall, Lawrence KS, 66045, USA; National Research Nuclear University, Moscow Engineering Physics Institute, 31 Kashirskoye Shosse, Moscow 115409, Russia ∗E-mail: [email protected] ............................................................................... Radio waves, perhaps because they are uniquely transparent in our terrestrial atmo- sphere, as well as the cosmos beyond, or perhaps because they are macroscopic, so the basic instruments of detection (antennas) are easily constructable, arguably occupy a privileged position within the electromagnetic spectrum, and, correspondingly, receive disproportionate attention experimentally. Detection of radio-frequency radiation, at macroscopic wavelengths, has blossomed within the last decade as a competitive method for measurement of cosmic particles, particularly charged cosmic rays and neutrinos. Cosmic-ray detection via radio emission from extensive air showers has been demon- strated to be a reliable technique that has reached a reconstruction quality of the cosmic-ray parameters competitive with more traditional approaches. Radio detection of neutrinos in dense media seems to be the most promising technique to achieve the gigan- tic detection volumes required to measure neutrinos at energies beyond the PeV-scale flux established by IceCube. In this article, we review radio detection both of cosmic rays in the atmosphere, as well as neutrinos in dense media. 1. Introduction Detection of ultra-high energy cosmic rays requires sensitivity to large volumes of target material. While established techniques for the detection of cosmic rays and high-energy neu- trinos have been extremely successful, as outlined throughout the remainder of this volume, many alternative techniques for probing the rare incident fluxes have been proposed.
    [Show full text]
  • The Cosmic-Ray Air-Shower Signal in Askaryan Radio Detectors
    Astroparticle Physics 74 (2016) 96–104 Contents lists available at ScienceDirect Astroparticle Physics journal homepage: www.elsevier.com/locate/astropartphys The cosmic-ray air-shower signal in Askaryan radio detectors Krijn D. de Vries a,∗, Stijn Buitink a, Nick van Eijndhoven a, Thomas Meures b, Aongus Ó Murchadha b,OlafScholtena,c a Vrije Universiteit Brussel, Dienst ELEM, Brussels B-1050, Belgium b Université Libre de Bruxelles, Department of Physics, Brussels B-1050, Belgium c University Groningen, KVI Center for Advanced Radiation Technology, Groningen, The Netherlands article info abstract Article history: We discuss the radio emission from high-energy cosmic-ray induced air showers hitting Earth’s surface be- Received 6 March 2015 fore the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which Revised 15 September 2015 should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino Accepted 13 October 2015 flux in ice. The in-air emission, the in-ice emission, as well as a new component, the coherent transition Availableonline28October2015 radiation when the particle bunch crosses the air–ice boundary, are included in the calculations. Keywords: © 2015 Elsevier B.V. All rights reserved. Cosmic rays Neutrinos Radio detection Coherent transition radiation Askaryan radiation 1. Introduction [24,25]. The expected GZK neutrinos are extremely energetic with en- ergies in the EeV range, while the flux at these energies is expected to We calculate the radio emission from cosmic-ray-induced air fall below one neutrino interaction per cubic kilometer of ice per year. showers as a possible (background) signal for the Askaryan radio- Therefore, to detect these neutrinos an extremely large detection vol- detection experiments currently operating at Antarctica [1–3].A ume, even larger than the cubic kilometer currently covered by the high-energy neutrino interacting in a medium like (moon)-rock, ice, IceCube experiment, is needed.
    [Show full text]
  • Recent Results from the Askaryan Radio Array
    Recent Results from The Askaryan Radio Array Amy Connolly∗, for the ARA Collaborationy The Ohio State University E-mail: [email protected] The Askaryan Radio Array (ARA) is an ultra-high energy (UHE) neutrino telescope at the South Pole consisting of an array of radio antennas aimed at detecting the Askaryan radiation produced by neutrino interactions in the ice. Currently, the experiment has five stations in operation that have been deployed in stages since 2012. This contribution focuses on the development of a search for a diffuse flux of neutrinos in two ARA stations (A2 and A3) from 2013-2016. A background of ∼ 0:01 − 0:02 events is expected in one station in each of two search channels in horizontal- and vertical-polarizations. The expected new constraints on the flux of ultra-high energy neutrinos based on four years of analysis with two stations improve on the previous limits set by ARA by a factor of about two. The projected sensitivity of ARA’s five-station dataset is beginning to be competitive with other neutrino telescopes at high energies near 1010:5 GeV. arXiv:1907.11125v1 [astro-ph.HE] 24 Jul 2019 36th International Cosmic Ray Conference -ICRC2019- July 24th - August 1st, 2019 Madison, WI, U.S.A. ∗Speaker. yfor collaboration list see PoS(ICRC2019)1177. ARA author list available at http://ara.wipac.wisc.edu/authorlist. c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). http://pos.sissa.it/ Recent Results from The Askaryan Radio Array Amy Connolly 1.
    [Show full text]
  • LUNAR GEOLOGY and IONISING RADIATION from a Revisionist Perspective
    LUNAR GEOLOGY AND IONISING RADIATION from a Revisionist Perspective Dr Bulcsu István Siklós1 ABSTRACT This paper starts with a brief overview of the well-known hazards of the lunar surface including radiation originating from cosmic, solar and lunar sources. The gamma-ray spectrometry results from the Apollo program are compared to the spectrometry from NASA's Lunar Prospector; NASA's own dosimetry results from the Apollo missions are also assessed, unavoidably reaching the conclusion that the numerous hazards of the lunar surface make any manned mission ill-advised if not impossible for the time being. A discussion of NASA's fabrication of lunar geology then follows, focusing on basalts, anorthosites, lunar meteorites and lunar dust. After introducing the standard Dry Moon theory, the issue of the true colour of the lunar surface is discussed. The metal and water contents of alleged lunar basalts are also considered. In the Lunar Anorthosites section, the "Genesis Rock" and the circumstances of its discovery and subsequent promotion are discussed, along with the Apollo 16 collection of anorthosites. We then look at a few examples of lunar meteorites, noting how their identification is based on the alleged "ground truth" Apollo samples. In the Moon Dust section the nature of the lunar regolith as seen on the Apollo photos is discussed, and we briefly investigate the official Apollo Dust-Brush and Anti-Dust Leggings, leading to the inevitable conclusion that the entire episode took place in a studio setting. I. RADIATION AND THE APOLLO MISSIONS 2 II. THE FABRICATION OF LUNAR GEOLOGY 11 1. LUNAR BASALTS 11 2.
    [Show full text]
  • Science & Technology
    IAS YAN Academy for Civil Services Pvt. Ltd. 2021 SCIENCE & TECHNOLOGY Complete Current Affairs Compilation Vol- I from July 2020 to March 2021 SCIENCE & TECHNOLOGY Content Biotechnology 2 Space Technology 6 IT & Computer 46 Health 55 Alternate Energy 71 Defence Technology 76 Miscellaneous & New discovery 79 P a g e | 1 BIOTECHNOLOGY Nobel Prize in Chemistry What is in news? This year‘s Nobel Prize in Chemistry has been awarded to two scientists who transformed a bacterial immune mechanism, called CRISPR, into a tool that can edit the DNA/genomes of everything from wheat to mosquitoes to humans. CRISPR CRISPR (clustered regularly interspaced short palindromic repeats) is a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea. The CRISPR-Cas system is a prokaryotic immune system. It defends against phage and conjugative plasmid infection. o A bacteriophage, also known informally as a phage, is a virus that infects and replicates within bacteria and archaea. o A plasmid is a small, extra-chromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. It can cause infection. Cas9 Cas9 – is one of the enzymes produced by the CRISPR system – which binds to the DNA and cuts it, shutting the targeted gene off. Significance The ability to cut DNA wherever we want has revolutionized the life sciences. This editing process has a wide variety of applications including basic biological research, development of biotechnology products, and treatment of diseases. CRISPR-based therapies hold promise for the treatment of cancer and inherited disorders such as sickle cell disease and for the prevention and treatment of infectious diseases.
    [Show full text]
  • Advanced Certification in Science - Level I
    Advanced Certification in Science - Level I www.casiglobal.us | www.casi-india.com | CASI New York; The Global Certification body. Page 1 of 391 CASI New York; Reference material for ‘Advanced Certification in Science – Level 1’ Recommended for college students (material designed for students in India) About CASI Global CASI New York CASI Global is the apex body dedicated to promoting the knowledge & cause of CSR & Sustainability. We work on this agenda through certifications, regional chapters, corporate chapters, student chapters, research and alliances. CASI is basically from New York and now has a presence across 52 countries. World Class Certifications CASI is usually referred to as one of the BIG FOUR in education, CASI is also referred to as the global certification body CASI offers world class certifications across multiple subjects and caters to a vast audience across primary school to management school to CXO level students. Many universities & colleges offer CASI programs as credit based programs. CASI also offers joint / cobranded certifications in alliances with various institutes and universities. www.casiglobal.us CASI India CASI India has alliances with hundreds of institutes in India where students of these institutes are eligible to enroll for world class certifications offered by CASI. The reach through such alliances is over 2 million citizens CASI India also offers cobranded programs with Government Polytechnic and many other institutes of higher learning. CASI India has multiple franchises across India to promote certifications especially for school students. www.casi-india.com Volunteering @ CASI NY CASI India / CSR Diary also provide volunteering opportunities and organizes mega format events where in citizens at large can also volunteer for various causes.
    [Show full text]
  • Hyneman Rachel.Pdf
    Near-Field Effects in Radio Frequency Emission from Particle Showers in a Dense Medium Rachel Hyneman, College of William & Mary Advisors: Dr. Patricia Vahle, College of William & Mary Dr. Stephanie Wissel, University of California, Los Angeles May 4, 2015 Abstract The SLAC T-510 Experiment studied the effects of a magnetic field upon the radio- frequency emission from particle showers in high-density polyethylene. Ultra-High En- ergy (UHF) and Very High Frequency (VHF) antennas were used to measure the radio frequency (RF) radiation from particle showers in the target. Special near field data runs were performed with the UHF antenna array positioned closer to the target (along the beam axis). The signal was split into two linearly polarized components, vertical and horizontal, arising from two different mechanisms: the Askaryan and Magnetic effects, respectively. Peak voltage data from the near-field runs was used to determine the behavior of the radiation amplitude as a function of distance from the target and angle made with respect to the beam line. Power spectral densities were produced using near field runs to analyze how various frequency ranges behaved as a function of 1 distance. Initial results indicate that the amplitude dependence of the peak voltage on 1 angle remains consistent even as the antennas are moved further from the target. A R correction describes the effects of moving away from the target well. Spectral analysis reveals unclear effects in the lower frequency ranges. Although near field interference might be expected, such variations are likely dominated by reflections of RF emission within the target.
    [Show full text]
  • Prospects of Probing the Radio Emission of Lunar Uhecrv Events
    Prospects of Probing the Radio Emission of Lunar UHECRv Events A. Aminaeia,∗, L. Chenb, H. Pourshaghaghic,d, S. Buitinke, M. Klein-Woltc, L. V. E. Koopmansf, H. Falckec,g aDepartment of Physics, University of Oxford, OX1 3RH, UK bNational Astronomical Observatories, Chinese Academy of Sciences, Beijing, China cDepartment of Astrophysics/IMAPP, Radboud University, Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands dEindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands eAstrophysical Institute, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium fKapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700 AV Groningen, The Netherlands gASTRON, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands Abstract Radio detection of Ultra High Energetic Cosmic Rays and Neutrinos (UHECRv) which hit the Moon has been investigated in recent years. In preparation for near-future lunar science missions, we discuss technical requirements for radio experiments onboard lunar orbiters or on a lunar lander. We also develop an analysis of UHECRv aperture by including UHECv events occurring in the sub-layers of lunar regolith. It is verified that even using a single antenna onboard lunar orbiters or a few meters above the Moon’s surface, dozens of lunar UHECRv events are detectable for one-year of observation at energy levels of 1018eV to 1023eV. Furthermore, it is shown that an antenna 3 meters above the Moon’s surface could detect lower energy lunar UHECR events at the level of 1015eV to 1018eV which might not be detectable from lunar orbiters or ground-based observations. Keywords: UHECRv, Cosmic Rays, Cosmic Neutrinos, Lunar Lander, Lunar Orbiter, Space Radio Experiment 1.
    [Show full text]
  • Trigger/DAQ Systems for the Radio Detection of Ultra-High Energy Neutrinos
    Trigger/DAQ Systems for the Radio Detection of Ultra-High Energy Neutrinos Eric Oberla CPAD, October 2017 1 OUTLINE • Background + detection mechanism • Overview of the ANITA and ARA Trigger/DAQ systems • Future directions: lowering the energy threshold of radio detectors with phased arrays 2 Neutrinos: An Ideal UHE Messenger • The GZK process: Cosmic ray protons (E > 1019.5 eV) interact with CMB photons Neutrinos point directly back to sources What type of detector is needed to discover these GZK neutrinos? • ~1 GZK neutrino/km2/year • Lint ~ 300 km 0.003 neutrinos/km3/year • Need a huge (>1000 km3), radio-transparent detector Ice has long (>km) radio attenuation lengths 3 Detection Principle: The Askaryan Effect • EM shower in dielectric (i.e ice) creates fast moving negative charge excess • Coherent radio Cherenkov radiation (P ~ E2) if λ < Moliere radius Typical e+, e-, γ scales: L ~ 10 m r ~ 10 cm Radio emission Observed at SLAC stronger than optical for ultra- high energy (UHE) neutrino-induced showers ANITA Collab., PRL 2007 4 Radio Detectors using Dense Media: Ice J. Alvarez-Muniz 5 ANITA Instrument Box: • 96 switched- capacitor array ANITA (‘scope’) channels • Signal conditioning • NASA Long Duration • Computer + GPU Balloon Payload event prioritizer • From float altitude (35- • Trigger system 40 km), instruments • ~300W, 600 lbs ~106 km3 of ice • Four flights (2006,2008, 2013, 2016) • 48 Quad-ridge horn antennas 200-1200 MHz • Event reconstruction using timing delay between antennas (interferometry) • Restrictive Power ANITA4, pre-launch Nov. 2016 (~600W) and weight (~4000 lbs) budget 6 ANITA4 included dynamically tunable notch filters to reject satellite CW • A large number of military satellites were launched between ANITA2 and the launch of ANITA3 ANITA3 livetime 74% • Serious interference at 260 MHz and ~380 MHz [P.
    [Show full text]
  • The Askaryan Radio Array (ARA) Detecting Neutrinos in Antarctica
    The Askaryan Radio Array (ARA) Detecting Neutrinos in Antarctica Jonathan Davies 1 Unanswered questions in Astro-Particle Physics What are the sources of the highest energy cosmic rays? Can we use cosmogenic neutrinos to learn about astrophysical objects? Is there new particle physics at ultra high energies and distances of propagation? 2 The GZK Effect and why we think there are UHEN At energies above ~1019.5eV cosmic rays will interact with CMB photons producing neutrinos Process is known as the GZK effect Auger and HiRes measurements of UHE cosmic rays consistent with GZK cut-off Guaranteed GZK neutrino flux, but how large? The Pierre Auger Collaboration (2010): Phys. Lett. B 685 (4–5): 239–246. HiRes 3 Collaboration, Astropart. Phys. 32 (2009) 53. Why High Energy Neutrinos? For Astronomers: UHEN as cosmic messengers Ne uThetrin Prettyos: Th Picturese only k nown messengerInfrareds X-Ray What extra information can we obtain Argument usingat P neutrinoseV ene rgies and above instead of photons? !"#$#%&'(#&$')*#+,'-.'/,01'!"#$% !$&'()*#&+%&+%,-%.%µ/"01% 2")34$&(+'% 2")34,5'6)3$78(,&1%5)"**1$1'%26% 78Radio9#1:'5%&$%;<=%!$&)155%"*%"::% Optical Neutrinos? 1+1$4#15 >&($)15%1?*1+'%*&%@A%B%%%%C1D%E Crab Nebula in visible (green), !"#$%&'&%('%)*"+,-)." radio (red) and X-ray (blue) /&'01%(%&*'%+ FG%>*('6%&9%*H1%H#4H15*%1+1$46% 21-+#"3'0-+($4."* !$&)15515%"+'%!"$*#):15% Neutrino small cross-section means For Particle Physicists: *H$&(4H&(*%*H1%(+#01$51%!"#$%!"&' they can penetrate further in space I1D 8< The1D%+1 300(*$#+& %'TeV1*1) *&(CoM)$5 Neutrino Beam Argument and at higher energies than photons and cosmic rays C&%49)3)%$,,'J1D%+1(*$#+&% '1*1)*#&+K%5,&74%':#3'$",';<=' %,9$37%#':(9> Neutrinos point back to sources, unlike cosmic rays 4 P.
    [Show full text]
  • Constraints on the Diffuse Flux of Ultra-High Energy Neutrinos from Four Years of Askaryan Radio Array Data in Two Stations
    Constraints on the Diffuse Flux of Ultra-High Energy Neutrinos from Four Years of Askaryan Radio Array Data in Two Stations P. Allison,1 S. Archambault,2 J.J. Beatty,1 M. Beheler-Amass,3 D.Z. Besson,4, 5 M. Beydler,3 C.C. Chen,6 C.H. Chen,6 P. Chen,6 B.A. Clark,1, 7, ∗ W. Clay,8 A. Connolly,1 L. Cremonesi,9 J. Davies,9 S. de Kockere,10 K.D. de Vries,10 C. Deaconu,8 M.A. DuVernois,3 E. Friedman,11 R. Gaior,2 J. Hanson,12 K. Hanson,3 K.D. Hoffman,11 B. Hokanson-Fasig,3 E. Hong,1 S.Y. Hsu,6 L. Hu,6 J.J. Huang,6 M.-H. Huang,6 K. Hughes,8 A. Ishihara,2 A. Karle,3 J.L. Kelley,3 R. Khandelwal,3 K.-C. Kim,11 M.-C. Kim,2 I. Kravchenko,13 K. Kurusu,2 H. Landsman,14 U.A. Latif,4 A. Laundrie,3 C.-J. Li,6 T.-C. Liu,6 M.-Y. Lu,3, y B. Madison,4 K. Mase,2 T. Meures,3 J. Nam,2 R.J. Nichol,9 G. Nir,14 A. Novikov,4, 5 A. Nozdrina,4 E. Oberla,8 A. O'Murchadha,3 J. Osborn,13 Y. Pan,15 C. Pfendner,16 J. Roth,15 P. Sandstrom,3 D. Seckel,15 Y.-S. Shiao,6 A. Shultz,4 D. Smith,8 J. Torres,1, z J. Touart,11 N. van Eijndhoven,10 G.S. Varner,17 A.G. Vieregg,8 M.-Z.
    [Show full text]