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Theresa Brandt 2 June 2007

CREAM: Improving Our Understanding of Cosmic Rays. Great Lakes Cosmology Workshop 8. Theresa Brandt 2 June 2007. CREAM I, Antarctica CREAM Collaboration. Power law in energy: Change in spectral slope: “Knee” at ~10 15 eV From  ≈ 2.7 to 3.0 Due to change in acceleration mechanism?

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Theresa Brandt 2 June 2007

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  1. CREAM: Improving Our Understanding of Cosmic Rays Great Lakes Cosmology Workshop 8 Theresa Brandt 2 June 2007 CREAM I, Antarctica CREAM Collaboration

  2. Power law in energy: • Change in spectral slope: • “Knee” at ~1015 eV • From  ≈ 2.7 to 3.0 • Due to change in acceleration mechanism? • What about propagation conditions? • Gather clues from composition • and primary to secondary ratios. All-particle CR Spectrum S. Swordy

  3. CR Origins: Supernova ... are good candidates because • they are point-like, stellar objects, as required by abundances. • SN shock lifetime implies Emax ~ Z x 1014 eV, which is a potential source of the knee. • typical SN luminosity at a few % efficiency could supply observed CRs. • multi-wavelength observations imply this efficient acceleration. Kepler's SNR Chandra Telescope

  4. CR Propagation M, S, & M, Prop. Transport Equation:

  5. CREAM Science Goals • Determine elemental composition from 1012 up to 1015 eV • Measure secondary to primary ratio (e.g. B/C) • Observe predicted “knee” in proton spectrum CREAM I Hang Test, Antarctica CREAM Collaboration

  6. Cosmic Ray Energetics and Mass 4 main subsystems: TCD (Z), TRD (E), SCD (Z), Cal (E) Timing Charge Detector, Transition Radiation Detector, Silicon Charge Detector, and Calorimeter Flown on a Long-Duration Balloon over Antarctica CREAM I: 42 day (16 Dec 04 - 27 Jan 05) CREAM II: 28 day (16 Dec 05 - 13 Jan 06) • Particle Detector Charge and Energy: • +1 ≤ Z ≤ 26 • 1012 eV <~ E <~1015 eV CREAM

  7. CREAM, Antarctica CREAM Collaboration NASA/CSBF

  8. Preliminary HEAO CRN Flux (m2 s sr GeV)-1 CREAM Cherenkov CREAM TRD Total Particle Energy (eV) S. Swordy, S. Wakely Oxygen Spectrum HEAO CRN

  9. Carbon Spectrum Preliminary HEAO HEAO Flux (m2 s sr GeV)-1 CRN CRN CREAM Cherenkov CREAM TRD Total Particle Energy (eV) S. Swordy, S. Wakely

  10. The CREAM Collaboration: University of Maryland H. S. Ahn, O. Ganel, J.H. Han, K.C. Kim, M. H. Lee, L. Lutz, A. Malinine, E. S. Seo, R. Sina, P. Walpole, J. Wu, Y. S. Yoon, S. Y. Zinn University of Chicago P. Boyle, S. Swordy, S. Wakely Penn State University N. B. Conklin, S. Coutu, S. I. Mognet Ohio State University P. Allison, J. J. Beatty, T. J. Brandt University of Minnesota J. T. Childers, M. A. DuVernois University of Sienna & INFN, Italy M. G. Bagliesi, G. Bigongiari, P. Maestro, P. S. Marrocchesi, R. Zei Ehwa Womans University, S. Korea H. J. Hyun, J. A. Jeon, J. K. Lee, S. W. Nam, I. H. Park, N. H. Park, J. Yang Northern Kentucky University S. Nutter Kent State University S. Minnick Goddard Space Flight Center L. Barbier Kyungpook National University, S. Korea H. Park Laboratoire de Physique Subatomique et de Cosmologie,Grenoble, France M. Mangin-Brinet, A. Barrau, O. Bourrion, J. Bouvier, B. Boyer, M. Buenerd, L. Eraud, R. Foglio, L. Gallin-Martel, Y. Sallaz-Damaz, J. P. Scordilis Centre d’Etude Spatiale des Rayonnements, Toulouse, France R. Bazer-Bach, J.N. Perie Universitad Nacional Auto´noma de Mexico, Mexico A. Menchaca-Rocha CREAM III assembly CREAM Collaboration

  11. Castellina & Donato HEAO (90) Simon (80) Mahel (77) Lezniak (78) Juliusson (74) Caldwell (77) Orth (78) Swordy (90) Top  bottom: =0.3, 0.46, 0.6, 0.7, 0.8 Dwyer (87) • Secondary flux reflects propagation conditions for a given source spectrum. • Ratios of s:p at given E reduces source dependence. • Assume ~ steady state. B:C Carbon as primary: • common stellar process end-product Boron as secondary: • stable, rarely stellar-synthesized • BBN abundence is rel. well known. • want properties like selected primary's. All-particle spectral index goes as the source and propagation energy indices: • 2.7 = 1.1+1+0.6

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