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Fl uorescence from A ir in Sh owers ( FLASH )

Proposal E-165. Fl uorescence from A ir in Sh owers ( FLASH ) J. Belz 1 , Z. Cao 2 , P. Chen 3* , C. Field 3 , P. Huentemeyer 2 , W-Y. P. Hwang 4 , R. Iverson 3 , C.C.H. Jui 2 , T. Kamae 3 , G.-L. Lin 4 , E.C. Loh 2 , K. Martens 2 , J.N. Matthews 2 , W.R. Nelson 3 , J.S.T. Ng 3 ,

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Fl uorescence from A ir in Sh owers ( FLASH )

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  1. Proposal E-165 Fluorescence from Air in Showers (FLASH) J. Belz1, Z. Cao2, P. Chen3*, C. Field3, P. Huentemeyer2, W-Y. P. Hwang4, R. Iverson3, C.C.H. Jui2, T. Kamae3, G.-L. Lin4, E.C. Loh2, K. Martens2, J.N. Matthews2, W.R. Nelson3, J.S.T. Ng3, A. Odian3, K. Reil3, J.D. Smith2, P. Sokolsky2*, R.W. Springer2, S.B. Thomas2, G.B. Thomson5, D. Walz3 1University of Montana, Missoula, Montana 2University of Utah, Salt Lake City, Utah 3Stanford Linear Accelerator Center, Stanford University, CA 4Center for Cosmology and Particle Astrophysics (CosPA), Taiwan 5Rutgers University, Piscataway, New Jersey * Collaboration Spokespersons

  2. Cosmic Rays have been observed with energies at up to ~1020 eV: • The flux (events per unit area per unit time) follows roughly apower law ~E-3 • Changes of power-law index at “knee” and “ankle”. Onset of different origins/compositions? Where does the spectrum stop?

  3. Discrepancy Between Two UHECR Experiments AGASA AGASA HiRes HiRes

  4. UHECR From Source to Detector CMB γ

  5. Greisen-Kuzmin-Zatsepin (GZK) Cut-off 3×1020 eV 50 Mpc ~ Size of local cluster (protons) • Protons above 6×1019 eV will loose sizable energy through CMB • Super-GZK events have been found with no identifiable local sources

  6. Extensive Air Showers Zoom on next slide

  7. Extensive Air Shower Development • Hadronic shower initiated by primary • Electromagnetic Shower produced by γ’s from p0 decays…

  8. Observation of Cosmic Ray with Fluorescence Technique • The two detector sites are located 12 km apart • Geometry of an air shower is determined by triangulation. • Energy of primary cosmic ray calculated from amount of light collected.

  9. Other Proposed Fluorescence Experiments • Carlos Escobar (Campinas, Italy) • Andrea Santangelo (Palermo, Italy) • - Lab. measurements induced by hard-x-ray photons • Paolo Privitera (Rome, Italy) • - similar approach to Kakimoto and Nagano • Hans Klages (Karlsruhe, Germany) • - Karlsruhe activities on Air Shower Light • Pierre Colin (LAPP, France) • - MacFLY Photons • Philippe Gorodetzky (College de France) • - Measurements planned at CERN

  10. UNIQUE LABORATORY ASTROPHYSICS OPPORTUNITY • High intensity e-/e+ beamsultra-fast (< 50 fsec), high energy (~30GeV/e) • ultra-high intensity (~ 1022 W/cm2) • very high repetition rate (10 Hz) • High fluence photon beams • 1. X-ray from undulator (~ 109 γ/pulse at 1.5 Å) • 2. Terawatt laser (at ~ 1 μm) • 3. Gamma-ray (up to ~ 15 GeV) through laser-particle beam Compton- backscattering • * Experiments can be performed with different combinations of these beams

  11. MEASURING FLUORESCENCE AT SLAC • Extensive Air Showers (EAS)are predominantly a superposition of EM sub-showers. • Important N2 transition (2P) not accessible by proton excitation; only e-beam can do it. • FFTB beam-line provides energy equivalent showers from ~1015 to ~1020 eV. • 108-1010 electrons/pulse at 28.5 GeV. • 2% of electron pulse bremsstrahlung option.

  12. FLASH useful for future UHECR ExperimentsGround-Based: The Pierre Auger Observatory • Hybrid detection • 1600 Cherenkov detectors 1.5 km gridin 3000 km2 • 4 fluorescence eyes – Comparable to HiRes 65 km

  13. Space-Based: EUSO, OWL/AirWatch

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