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G.-L. Lin National Chiao-Tung U. Taiwan

KAW4 2006. Laboratory Astrophysics in Taiwan- studying properties of cosmic ray showers using NSRRC 1.5 GeV electron beam. G.-L. Lin National Chiao-Tung U. Taiwan. General Features of Laboratory Astrophysics Fluorescence Measurements Using SLAC 28.5 GeV e - beam

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G.-L. Lin National Chiao-Tung U. Taiwan

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  1. KAW4 2006 Laboratory Astrophysics in Taiwan-studying properties of cosmic ray showers using NSRRC 1.5 GeV electron beam G.-L. Lin National Chiao-Tung U. Taiwan

  2. General Features of Laboratory Astrophysics Fluorescence Measurements Using SLAC 28.5 GeV e- beam Cherenkov Measurements Using NSRRC 1.5 GeV e- beam Concluding remarks Outline

  3. 1. Calibration of observations - Precision measurements to calibrate observation processes - Development of novel approaches to astro-experimentation - Though non-exotic, value to astrophysics most certain 2. Investigation of dynamics - Astro-conditions hard to recreate in the lab - Many MHD or plasma processes scalable by extrapolation 3. Probing fundamental physics - Underlying physical principles in nature still to be discovered - Extreme limits render signatures faint – a challenging task - Though challenging, potential returns in science most significant General Features of LabAstro-Using Lasers and Particle Beams as Tools - P. Chen, Workshop on laboratory astrophysics using high intensity particle and photon beams.

  4. Fluorescence from Air in Showers (FLASH) J. Belz1, D. Bergman5, Z. Cao2, F.Y. Chang4, P. Chen3*, C.C. Chen4, C.W. Chen4, C. Field3, P. Huentemeyer2, W-Y. P. Hwang4, R. Iverson3, C.C.H. Jui2, G.-L. Lin4, E.C. Loh2, K. Martens2, J.N. Matthews2, J.S.T. Ng3, A. Odian3, K. Reil3, J.D. Smith2, P. Sokolsky2*, R.W. Springer2, S.B. Thomas2, G.B. Thomson5, D. Walz3, A. Zech5 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

  5. The Motivation For FLASH • The ultra-high energy cosmic ray (UHECR) spectra measured by HiRes (fluorescence) and AGASA (scintillation counter ground array) differ significantly in slope for E~1020 eV. • This discrepancy can be possibly accounted for by a systematic difference in the energy scale (~25%)

  6. The Detection of UHECR Air Fluorescence Detector: HiRes Hybrid: Auger AGASA Detector

  7. The Energy Reconstruction of UHECR in the Fluorescence Technique Integrating the energy deposition along the path and correcting for missing energy D. J. Bird et al., APJ 424, 491-502,(1994) Fitted from the atmospheric scintillation process—model independent! • How well do we know the fluorescence efficiency? • Can the fluorescence yield accurately reconstruct the longitudinal profile Ne(X)?

  8. SLAC E-165 ExperimentFluorescence in Air from Showers (FLASH)28.5 GeV e- beam

  9. The thin target Experiment Layout Toroid Beam spot monitor Grating spectrograph Beam dump Main fluorescence chamber Fluorescence vessel bafflers Filter wheel PMT LEDs

  10. Kakimoto et al., NIM A372 (1996) Nagano et al., Astroparticle Physics 20, 293-309 (2003) Belz et al., to appear in Astroparticle Physics; astro-ph/0506741 Huentemeyer et al., presented at ICRC 05 The Existing Air Fluorescence Yield Measurements—without Showers

  11. Thick Target apparatus Ion chamber Available shower depth: 2,4,6,8,10,14 radiation lengths

  12. Universal electron energy distribution in different shower ages F. Nerling et al., astro-ph/0506729 • The shower age S=3X/(X+2Xmax) determines the • electron-positron spectrum. • Mean electron (positron) energies near the • shower maximum are very similar for primary • 30 GeV electrons and primary 1019 eV protons • —superposition at works! • SLAC is a right place as 31010 eV5  108/bunch~1019 eV. Back to 15

  13. The Fluorescence Technique Validated • Comparison of fluorescence yields and ionization longitudinal profiles. The sum of points in each profile is independently normalized to unity. • The ion chamber data points correspond to slightly larger radiation lengths. • Both fluorescence and ionization longitudinal profiles agree well with simulations(Geant3 and EGS4). astro-ph/0510375, to appear in Astroparticle Physics

  14. T.C. Liua, F.Y. Changa, C.C. Chenb,C.W. Chenb, Y. T. Yangd, K.T Hsu.d,M.A. Huangc, P.W.Y. Hwangb, G.L. Lina Studying Cherenkov light from air showers with NSRRC 1.5 GeV e- beam (a) Institute of Physics, National Chiao-Tung University, 1001 Ta Hsueh Rd., Hsin-chu, 300, TAIWAN, ROC. (b) Institute of Astrophysics, National Taiwan University, 1, Sec. 4, Roosevelt Rd. Taipei, 106, TAIWAN, ROC. (c) Department of Physics, National United University, 1, Lien-da, Kung-ching Li, Miao-Li, 36003, TAIWAN, ROC (d) National Synchrotron Radiation Research Center

  15. Cherenkov light is an important background in the fluorescence measurement. A correct estimation of this contribution is needed. F. Nerling et al.for Auger Collaboration,ICRC 05 Previous estimation of Cherenkov contribution were based upon simulations. It is desirable to have a direct measurement. Motivation Page 12 Page 30

  16. NSRRC (National Synchrotron Radiation Research Center) 1993 Apr. First beam stored in the storage ring Oct. Taiwan Light Source Dedication Ceremony 2000 Feb. 1.5 GeV full energy injection

  17. Each bunch carries 109 electrons The 1.5 GeV electron beam National Synchrotron Radiation Research Center The electrons are injected from booster ring with 10 Hz frequency Total energy ~ 1 EeV

  18. Exp

  19. Thin Foil 1.5 GeV electron beam Light path Removable radiator system 10cm 1 r.l.=8.9 cm 2.9cm 10cm Experimental Platform Each block contains 1/3 R.L. Lateral Profile

  20. The CCD quantum efficiency is not uniform Fluorescence contributions arise between 300 nm and 400 nm.

  21. CCD Background—beam off

  22. We have also subtracted the background with beam on and the chamber in vacuum.

  23. 2.3 r.l. Shower maximum

  24. 5 r.l. Shower maximum

  25. Preliminary Shower maximum occurs at 2.3 r.l. Counts at 0 r.l. subtracted

  26. GEANT4 simulations e- e+ γ One incident electron Shower maximum

  27. One incident electron 15 blocks

  28. Shower longitudinal profiles @4.5106 simulations Shower maximum occurs near 2.3 r.l.

  29. Preliminary A consistency check Separately normalized to respective total counts/event #

  30. The simulated longitudinal profile has to be folded with Cherenkov photon yield. The Cherenkov photon yield verse particle energy Back to 15

  31. Geant 4 simulation with Cherenkov photons

  32. The fluorescence contribution has to be subtracted from the data—using simulations tested by FLASH thick target experiment. Angular distributions of Cherenkov photons will be studied as well.

  33. A brief history of laboratory astrophysics program in Taiwan was reviewed. We have shown the results of FLASH thin and thick target runs. The rationale of FLASH thick target run is applied to measure the Cherenkov light from particle showers using NSRRC 1.5 GeV electron beams. Work in progress! Concluding Remarks

  34. Result: Fluorescence Spectrum 22nd Texas Symposium on Relativistic Astrophysics

  35. Preliminary Statistics low at low and high radiation lengths --to be improved

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