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What are Cosmic Rays? A short history What do we know now about CRs

UHECR detection from the Space. …by Dmitry Naumov(JINR). What are Cosmic Rays? A short history What do we know now about CRs What are Extensive Air Showers? A short history How to detect EAS? Back to CR – their energy spectrum from EAS detection Why all these is interesting?

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What are Cosmic Rays? A short history What do we know now about CRs

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  1. UHECR detection from the Space …by Dmitry Naumov(JINR) • What are Cosmic Rays? • A short history • What do we know now about CRs • What are Extensive Air Showers? • A short history • How to detect EAS? • Back to CR – their energy spectrum from EAS detection • Why all these is interesting? • Ultra High Energy and GZK Cut-Off • Various speculations • EAS detection from the Space • EUSO, OWL, TUS • UHECR identification: (p, Fe, (anti) neutrino) • Expected Performance • Conclusions PISA INFN October 2003

  2. Courtesy by V.Naumov

  3. Courtesy by V.Naumov

  4. Even very well isolated gold-leaf electroscopes are discharged at a slow rate. … observed by scientists before 1900 • J.Elster, H. F.Geitel, C.Wilson investigated this phenomenon and concluded that some unknown source of ionizing radiation existed. Wilson even surmised that the ionization might be • “…due to radiation from sources outside our atmosphere, possibly radiation like Röntgen rays or like cathode rays, but of enormously greater penetrating power.” A gold-leaf Bennet-type electroscope (ca. 1880s) manufactured by Ducretet. 1900-1901 Soon after, two Canadian groups, Ernst Rutherford and H. Lester Cooke (1903) at McGill University, and J. C. McLennan and E. F. Burton (1902) at the University of Toronto showed that 5 cm of lead reduced this mysterious radiation by 30%. An additional 5 t of pig lead failed to reduce the radiation further. Courtesy by V.Naumov

  5. Courtesy by V.Naumov

  6. Victor Hess won The Nobel Prize in Physics 1936 "for his discovery of cosmic radiation" . Background of the slide: H.E.S.S. (High Energy Stereoscopic System) a next-generation system of Imaging Atmospheric Cherenkov Telescopes for the investigation of cosmic gamma rays in the 100 GeV energy range. Classic references: • V.F. Hess, Physik. Zeitschr. 12 (1911) 998. • V.F. Hess, Physik. Zeitschr. 13 (1912) 1084. • V.F. Hess, Physik. Zeitschr. 14 (1913) 610. Courtesy by V.Naumov

  7. Courtesy by V.Naumov

  8. Up to now EAS are detected on the Earth ground • Today the largest ground detector Pierre Auger in Argentina camps will cover ~3000 km2 surface and detect both: • Charged particles • Fluorescent light

  9. Courtesy by V.Naumov

  10. GZK ~ 5×1010 GeV 2nd knee ~ 4×108 GeV 1st knee ~ 3×106 GeV ankle ~ 5×109 GeV Courtesy by V.Naumov

  11. How UHECRs are accerelated? • Top down (TD, Big-Bang Remnants, WIMPs etc) • Bottom Up (shock waves, RadioGalaxies, etc) • Diffusion acceleration at Newtonian Shocks • Unipolar induction (rotating magnetic fields strong electric field) • Non-linear particle-wave interaction • Active Galactic Nuclei and Dead Quasars • Neutron Stars • Gamma Ray Bursts • etc… A lot of speculation but nobody knows (and if knows does not tell us) the truth…

  12. Do UHECRs come from the same Source? Isotropic distribution of CR events with energy > 1019 eV observed (Takeda et al., 1999). AGASA Super GZK event distribution.

  13. What is Greisen-Zatsepin-Kuzmin CutOff ? • 2.73°K cosmic microwave background (CMB) • (GZK) Cutoff Eth > 5.1019eV

  14. NB: The energy threshold for the iron is about 50 times higher… Hires is a fluorescent detector AGASA is a charge track detector • A lower energy data suggests a dominance of the protons… • The AGASA data seems to conflict to both Hires and GZK prediction. • There is also a 2 times difference in the flux measurement between Hires and AGASA at low energies!

  15. How do UHECRs propagate? Strong neutrino flux @ E>1021eV can propagate unattenuated and give us photons, nucleons and pions interacting with CNB! Z0 burst from the annihilation with CNB relic neutrinos in Virgo Cluster. The decay products of Z0 are gamma rays, nucleons and neutrinos, as firmly established by the CERN LEP experiments.

  16. Spectrum of energy • Nature (p, Fe, g, n… ) • Sources unknown ! unknown! unknown! • Unknown in addition :Is GZK limit is violated or no ? What do we know about UHECRs today?

  17. Who and How is going to address the problem(s)?

  18. Courtesy by C.Lauchaud

  19. The Auger Observatory is now under construction. The first step consisted of 40 surface detectors (out of the 1600 for the total array) over an area of about 40 km2 and 2 fluorescence telescopes (out of 24 for the final setup). Thirty of the surface detectors were equipped with electronics and have worked under stable conditions since January 2002. More than 70 air showers were detected in hybrid mode (seen both by the surface and fluorescence detectors), and a few hundreds of events with estimated energies above 1 EeV (1018 eV) were observed by the surface array alone. AGASA and Hires are still collecting the data

  20. Concept of TUS/TUS2 space free flyer 16x16 PMTs Fresnel mirror 10 rings Focal distance is 1.5 m Field of View is 7.3o

  21. [mm] Fresnel Mirror R&D Measured vs theory mold production in JINR/Dubna Space qualified carbon-plastic Fresnel mirror to be produced @ “Luch” (Syzran) Mirror mold section Measured - theory Ring number The light spread radius on the focal plane: 90% 80% 70%

  22. EUSO: • ISS stationed optics • 2 m diameter Fresnel lenses • 30o FoV • 3 years data taking • Now end of Phase A

  23. Same detector observing from above will see much more events: S=2H2tan2 However there is a price for that: number of photons is much smaller! NISS = S*/4 H2 Nemitted =0.5 10-12 S* Nemitted = 104 ES* (E is in units 1020eV) • There further factors: • Loss in the atmosphere • Loss in the detector (optics, electronics, trigger…)  Thus one can not go too below in energy and can not have too small optics… H

  24. UHECR Atmoshpere shower Attenuation in air Air fluoresence Cerenkov light Reflection from the Earth

  25. Extreme Universe Space Observatory

  26. The Background. The night view of the EARTH @moonless night we expect 500 photons m-2 ns-1 sr-1, corresponding to  0.3 p.e./s

  27. What if UHECRs are neutrinos?

  28. Conclusions • Whatever the scientific objectives are EUSO is a very interesting and power tool to enter the game! • EUSO will collect in 3 years ~few 1000 of events • EUSO will be able to separate (to some extent) p, Fe and neutrino • 20-30% error for the energy measurement is expected

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