Cosmic Ray Energetics And Mass(CREAM)

Moriond 2005

Eun-Suk SeoInstitute for Physical Science and Technology

Department of PhysicsUniversity of Maryland

Eun-Suk Seo, University of Maryland

Cosmic Ray Energy Spectra

Space & HeliosphericPhysics

BESS

ATIC

CREAM

Particle Astrophysics

ground based

AMS

Is the “knee” due to a limit in SNR acceleration?

SNR acceleration limit:

• The spectrum extends several orders of magnitude beyond the highest energies thought possible for supernova shocks

• And, there is a “knee” (index change) above 1015 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 ΤeVΖZeBVT

cvE 100~~max ×

Ankle

Knee

Si matrix Measure incident charge 1≤Z≤28

Target SectionForce 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

CalorimeterMeasure energy and shower core trajectory with a fully active BGO calorimeter (22 X0, ~1.14λI)

102

103

104

105

106

Energy (GeV/nucleon)

102

103

104

105

E2.

75 d

N/d

E (

m2 s

r s)

-1 (

GeV

/n)1.

75Protons

Helium

Is there a composition change at high energies?

Eun-Suk Seo, University of Maryland

ATIC fills the gap in P & He SpectraAhn and Seo for the ATIC collaboration, Proc. 28th ICRC, 4, 1833, 2003.

Protons

Helium

Eun-Suk Seo, University of Maryland

Calorimeter

• 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

• Acceptance0.3 m2sr for Z = 1 & 2 1.3 m2sr for Z ≥ 3

Upper TRD Module

Lower TRD Module

Target1

Mission Support ElectronicsTRD

Gas

TCD

Cherenkov Layer

71 inches

SCDS0/S1S2S3Target2

Modular Design for Recovery

Eun-Suk Seo, University of Maryland

TRD Module

Calorimeter Module

CDM

Solar Array

Eun-Suk Seo, University of Maryland

WSCROCC

OCCPalestine

LOS

S-band Cmd

S-band tlm

IRIDIUMARGOS

TDRSSGPS

ESCWFF

ScienceOperationCenterUMD

Scienceon the ICE

CREAM Flight Operation

Eun-Suk Seo, University of Maryland

Record Breaking Flight

Launch12/16/04

Landing1/27/05

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

Eun-Suk Seo, University of Maryland

Alti

tude

(ft)

Latit

ude

(deg

)

Flight profile

Eun-Suk Seo, University of Maryland

Instrument functions well

An example event: ~10 TeV Fe

Eun-Suk Seo, University of Maryland

Flight Data: Very Preliminary Charge DistributionWithout corrections or cuts

N

Beam Test Data

Eun-Suk Seo, University of Maryland

Very Preliminary Energy Deposit Distribution

Exploring Supernova Acceleration Limit

• 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

Protons

Helium

O

Fe

Cumulative Energy Reach of CREAMProtons

1000 days

240 days

140 days

Helium

140 days

240 days

1000 days

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

TRD

Bor

on/C

arbo

n R

atio

Energy (GeV/n)1 10 102 103

Eun-Suk Seo, University of Maryland

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.

CREAM Collaboration

University of MarylandH.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 ChicagoJ. Capodagli, C. Smith, S. Swordy

Penn State UniversityN.B. Conklin, S. Coutu, S.I. Mognet

Ohio State UniversityJ.J. Beatty

University of MinnesotaJ.T. Childers, M.A. Duvernois

Northern Kentucky UniversityS. Nutter

University of Siena & INFN, ItalyM.G. Bagliesi, G. Bigongiari, P. Maestro, P.S. Marrocchesi, R. Zei

Ewha Womans University, S. KoreaJ.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. KoreaH.J. Kim, Y.J. Kim, H. Park

Laboratorire de Physique Subatomique et de Cosmologie, Grenoble, FranceM. Buenerd, A, Barrau, L. Derome, K. Protasov

Centre d'étude Spatiale des Rayonnements, Toulouse, FranceR. Bazer-Bachi

Instituto de Fisica, Universidad Nacional Autonoma de Mexico, MexicoA.Menchaca-Rocha