R&D for Radio Detection Ad M. van den Berg

1. R&D for Radio DetectionAd M. van den Berg R&D and Astroparticle Physics meeting 8 January 2008 ASPERA R&D Lisbon AMvdB

2. Outline • Introduction • Cosmic Rays in Air • Cosmic Rays in Dielectric Solids • R&D next years To make further progress, particularly in the field of cosmic rays, it will be necessary to apply all our resources and apparatus simultaneously and side-by-side ASPERA R&D Lisbon AMvdB

3. Physics Motivation • Sources of UHE cosmic events • Energy spectra of selected (point) sources • Multi-messenger detection (cosmic rays, high-energy photons, neutrinos) • Interactions of UHE particles with nuclei (HEP) ASPERA R&D Lisbon AMvdB

4. Introduction • Radio detection of UHE cosmic events goes back to the 1960’s • Askaryan (Cherenkov radiation) • dielectric solids: rock salt, ice, lunar regolith • Allan, Jelley, Kahn, and Lerge (geo-synchrotron radiation) • atmosphere of the Earth • Coherent at frequencies where the shower thickness is comparable to the wavelength of the emitted radiation • solids 10 cm -» GHz • air 10 m -» 10 MHz • Signal amplitude ≈ E2 • Large penetration depth of EM radiation • “Simple” detection technique ASPERA R&D Lisbon AMvdB

5. Other Techniques • Bremsstrahlung • molecular Bremsstrahlung; will be tested at Pierre Auger Observatory: AMBER • Active and Passive Radar • knowledge on lifetime of free electron required at a height of many 10’s of km; tested at various places (USA, Europe) Scharf, RWTH Terra Incognita; efforts should continue along these lines ASPERA R&D Lisbon AMvdB

6. Large volumes (~109 kg sr) • EeV CR ~ 100/(km2 yr 2 sr) • Auger Observatory with z < 60o • S 3,000 km2 & E > 1 EeV: 105 / yr • N 10,000 km2 & E > 10 EeV: 6x103 / yr • EeV GZK < 300/(km2 yr 2 sr) • Interaction probability ~ 0.2% / km • KM3NeT / Ice3: 1 km3 water;  < 90o • 0.5 / yr ASPERA R&D Lisbon AMvdB

7. Present Status • Air-shower observations are becoming “standard”; coincidences with EAS arrays !! • data: energy, pointing, horizontal showers; understanding: absolute normalization, signal shapes, dependence on composition, polarization • application to a large scale: design studies are being made (pitch between stations, triggering algorithms) • Dielectric solids have only p.o.p. in the laboratory • data: energy and polarization (SLAC, ANL) • understanding: no correlation (yet) with any cosmic event simultaneously detected in another detector • application to a large scale: design studies have been made, new target sites being investigated ASPERA R&D Lisbon AMvdB

8. Different “Targets” • air • CODALEMA (F) • LOFAR (NL,D,UK) • LOPES and LOPES* (D) • Pierre Auger (Argentina) • IceCube (Antarctica) moon - GMRT (India) - LORD (in orbit) - LRX (on surface) - NuMoon (NL,D,UK) • ice and salt • Anita (Antarctica) • Arianna (Antarctica) • FORTE (Greenland) • RICE (Antarctica) • Salsa (USA) ASPERA R&D Lisbon AMvdB

9. Radio with Air as Target 24/7, statistics !! Omni directional Directional ASPERA R&D Lisbon AMvdB

10. Radio with Air as Target • Existing arrays • CODALEMA, LOPES, LOFAR • Upcoming arrays • IceCube, Pierre Auger • Strategy is to develop solitary systems with intelligence at the front end to remove background noise (RFI) predominantly from transients • Keywords: • theory & simulations (signal development, LDF) • engineering (power, wireless, self-triggering, calibration) • physics (pointing, composition, efficiency) ASPERA R&D Lisbon AMvdB

11. Radio R&D @ Auger • Auger South is perfect radio test bed for EAS (E > 0.1 EeV) • Low RFI levels (compared to rural areas) • Co-locate about 120 antennas inside the baseline SD array • Reduce Eth to .1 EeV using infill tanks (AMIGA) • Add additional FD telescopes for nearby showers (HEAT) • Add muon • Expertise as input to engineer a very large array (many 1000 km2; e.g. Auger North) ASPERA R&D Lisbon AMvdB

12. Example of 2 EeV event ASPERA R&D Lisbon AMvdB

13. Long-term Behavior (~3 m) Events recorded with radio @ Auger Long-term behavior of noise SD SD + Plastic Scintillators SD + PS + radio Timmermans, RU UTC LST 2 months 3 antennas separated by 100 m 1 event / 2 days ASPERA R&D Lisbon AMvdB

14. Event reconstruction • Beam forming • Radio signals come from the direction as determined from SD • Our signals are from real Cosmic-Ray events !! Timmermans, RU NS EW ASPERA R&D Lisbon AMvdB

15. Filtering Techniques Events recorded with radio @ LOPES* reduction of RFI using - median filtering techniques - number of zero crossings - ratio width and height - wavelet analysis Gemmeke, FZK ASPERA R&D Lisbon AMvdB

16. Self-triggered Events Dallier, Subatech ASPERA R&D Lisbon AMvdB

17. Radio with Solids as Target moon ice Westerbork Synthesis Radio Telescope Alvarez Nuñez, Santiago de Compostela rock salt $$$$ salt mines ? ASPERA R&D Lisbon AMvdB

18. Radio with Solids as Target • Existing experiments • ANITA, (FORTE & GLUE), GMRT, NuMoon/WSRT, (RICE) • Upcoming infrastructures • ARIANNA, LORD, NuMoon/LOFAR/SKA, SalSA • Strategy is to use existing infrastructures (WSRT, GMRT, LOFAR); to use & develop dedicated systems (Anita, LORD, Salsa) • Keywords: • theory & simulations (signal development and attenuation) • engineering (self-triggering, calibration, space) • physics (efficiency, neutrino versus cosmic ray) ASPERA R&D Lisbon AMvdB

19. Dielectric Materials ASPERA R&D Lisbon AMvdB

20. Results ANITA @ SLAC 4 hrs WSRT data PRELIMINARY Saltzberg, UCLA em shower in sand Scholten, University of Groningen power (a.u.) ASPERA R&D Lisbon AMvdB

21. Salt Deposits Mt/y ASPERA R&D Lisbon AMvdB

22. Exclusion Limits • AGN • PR • M(B) • GZK • ESS • PJ • KKSS • TD • PS • GRB • WB Kravchenko, MIT ASPERA R&D Lisbon AMvdB

23. Exclusion Limits LORD h = 250 km 365 d SalSA 1 km3 365 d WSRT 20 d LOFAR 30 d SKA LFB 365 d ASPERA R&D Lisbon AMvdB

24. R&D efforts • Radio from Air • Radio from Solids • Other R&D ASPERA R&D Lisbon AMvdB

25. R&D for Radio from Air • Comparison between theory and data • efficiency and pitch for antenna grid • resolution for energy, arrival direction, and composition • optimization of simulations • Development of low-power (5 W), radio-quiet solitary stations • optimization of electronics (system integration) • band width and sampling rate • cost engineering • Development of first and second level trigger • hard- and software filtering • Monitoring procedures • atmosphere, system health • Deploy engineering array at Southern Site Auger Observatory ASPERA R&D Lisbon AMvdB

26. R&D for Radio from Solids • Further develop theory • separate signals induced by neutrinos and cosmic rays • shower near surface of dielectric material • emission via transition radiation • Hybrid detection systems • Antarctica (IceCube) or Acoustic + Radio in salt/ice (ARIANNA) • Measure attenuation lengths • Ice, salt, regolith (Lunar Radio Astronomy Explorer) • Develop efficient trigger algorithm for observatories with streaming data (LOFAR, SKA) ASPERA R&D Lisbon AMvdB

27. Further R&D • Continue efforts • development of radar detection of cosmic rays (Eurocosmics?) • explore properties of salt (mines) in Europe • Laboratory (Frascati?) measurements (together with acoustic?) • high intensity pulsed beams to test • radio intensity as function of angle wrt Č and frequency • radar reflection (life time free electron) • pulse shape • yield of molecular Bremsstrahlung as function of frequency • Connection to other Fields and Industry • radio astronomy • event detection in noisy environment (digital trigger, signal analysis) • low-power electronics, solitary systems ASPERA R&D Lisbon AMvdB

28. Summary • Radio detection of cosmic rays and neutrinos • complementary technique • contained event (energy determination) • Last 5 years progress has been substantial • air showers: theory and experiment • dielectric solids: proof of principle • Next 5 years • extension to highest energy and larger scales (many km2) • cross check with other techniques • Europe plays an important role (air showers & lunar regolith) • involve SME’s • Continued exploring R&D • salt layers, radar detection ASPERA R&D Lisbon AMvdB