Cosmic Ray Energetics And Mass (CREAM) Moriond 2005

Transcription

1 Cosmic Ray Energetics And Mass (CREAM) Moriond 2005 Eun-Suk Seo Institute for Physical Science and Technology Department of Physics University of Maryland

2 Cosmic Ray Energy Spectra BESS Space & Heliospheric Physics ATIC Particle Astrophysics CREAM AMS ground based

3 Is the knee due to a limit in SNR acceleration? The spectrum extends several orders of magnitude beyond the highest energies thought possible for supernova shocks Knee And, there is a knee (index change) above ev SNR Signature: Characteristic elemental composition change over two decades in energy below and approaching the knee Direct measurements of individual elemental spectra can test the supernova acceleration model Ankle SNR acceleration limit: v Emax ~ ZeBVT ~ Ζ 100ΤeV c

4 Si matrix Measure incident charge 1 Z 28 Target Section Force nuclear interactions with three 10 cm thick layers of carbon Provide a trigger and auxiliary measurements of the incident particle charge and trajectory with plastic scintillator strip hodoscopes Calorimeter Measure energy and shower core trajectory with a fully active BGO calorimeter (22 X0, ~1.14λ I )

5 Is there a composition change at high energies? 10 5 E 2.75 dn/de (m 2 sr s) -1 (GeV/n) Protons Helium Energy (GeV/nucleon)

6 ATIC fills the gap in P & He Spectra Ahn and Seo for the ATIC collaboration, Proc. 28th ICRC, 4, 1833, Protons Helium

7 Three Complementary Charge Measurements Timing-Based Charge Detector Pixelated Silicon Charge Detector Scintillating Fiber hodoscope Two Complementary Energy Measurements Transition Radiation Detector (velocity for Z > 3) Tungsten-Scintillator Calorimeter (energy for Z 1) In-flight cross-calibration with Z > 3 particles in both detectors ensures best possible energy determination Acceptance 0.3 m 2 sr for Z = 1 & m 2 sr for Z 3 S0/S1 TRD Gas TCD Upper TRD Module Cherenkov Layer Lower TRD Module Target1 Target2 Calorimeter Mission Support Electronics SCD S2 S3 71 inches Modular Design for Recovery

8 TRD Module Calorimeter Module CDM Solar Array

9 IRIDIUM ARGOS GPS CREAM Flight Operation TDRSS LOS ROCC Science on the ICE Science Operation Center UMD OCC Palestine ESC WFF S-band Cmd S-band tlm WSC

10 Record Breaking Flight The CREAM payload flew 41 days, 21 hr, 31min in three circumnavigations of the South Pole between 12/16/04 and 1/27/05 - Previous LDB record was broken by >10 days - 14,000 nautical miles traveled - Record-Breaking Flight Press Release on 1/31/05 Launch 12/16/04 Landing 1/27/05

11 Altitude (ft) Latitude (deg) Flight profile

12 Instrument functions well An example event: ~10 TeV Fe

13 Flight Data: Very Preliminary Charge Distribution Without corrections or cuts Beam Test Data N

14 Very Preliminary Energy Deposit Distribution

15 Exploring Supernova Acceleration Limit Protons O Helium Fe The left Figure compares simulated data (red squares) for protons (upper) and Helium (lower) from a 40-day flight of the Calorimeter with prior data - These are the highest energy direct measurements of p and He - These are unique Calorimeter data below the TRD threshold The right Figure compares simulated data (red squares) for Oxygen (upper) and Iron (lower) from a 40-day flight of the TRD with prior data

16 Cumulative Energy Reach of CREAM Protons Helium 140 days 140 days 240 days 240 days 1000 days 1000 days

17 What is the history of cosmic rays in the Galaxy? Comparison of expected data from a 40-day flight (black circles) of the TRD with prior data - First B/C ratio at these high energies to distinguish among the propagation models Boron/Carbon Ratio TRD Energy (GeV/n)

18 The CREAM payload has been fully recovered - NSF/OPP set up field camp at impact site - Payload was disassembled to fit inside the Twin Otter and returned to McMurdo with five flights - Payload is to be air-shipped to the U.S.

19 CREAM Collaboration University of Maryland H.S. Ahn, O. Ganel, K.C. Kim, M.H. Lee, L. Lutz, A. Malinin, E.S. Seo, Y.S.Yoon, S.Y. Zinn University of Chicago J. Capodagli, C. Smith, S. Swordy Penn State University N.B. Conklin, S. Coutu, S.I. Mognet Ohio State University J.J. Beatty University of Minnesota J.T. Childers, M.A. Duvernois Northern Kentucky University S. Nutter University of Siena & INFN, Italy M.G. Bagliesi, G. Bigongiari, P. Maestro, P.S. Marrocchesi, R. Zei Ewha Womans University, S. Korea J.H. Han, H.J. Hyun, M.Y. Kim, J.K. Lee, S.W. Nam, I.H. Park, N.H. Park, J. Yang Kyungpook National University, S. Korea H.J. Kim, Y.J. Kim, H. Park Laboratorire de Physique Subatomique et de Cosmologie, Grenoble, France M. Buenerd, A, Barrau, L. Derome, K. Protasov Centre d'étude Spatiale des Rayonnements, Toulouse, France R. Bazer-Bachi Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico A. Menchaca-Rocha