cosmic rays eun-suk seo 3 - gssi · cosmic rays eun-suk seo 19 • beam measurements for 150 gev...
TRANSCRIPT
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Eun-Suk Seo Inst. for Phys. Sci. & Tech. and
Department of Physics University of Maryland
Multiple Messengers and Challenges in Astroparticle Physics, October 6-17, 2014
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Cosmic Rays Eun-Suk Seo
Hess Centennial: Discovery of Cosmic Rays
• In 1912 Victor Hess discovered cosmic rays with an electroscope onboard a balloon – Reached only ~ 17,000 ft but measured an
increase in the ionization rate at high altitude (1936 Nobel Prize in Physics for this work)
• Discoveries of new particles in cosmic rays - Positrons by Anderson in 1932 (Nobel ‘36) - Muons by Neddermeyer & Anderson in 1937 - Pions by Powell et al. in 1947 (Nobel’ 50) - …....
• "Direct Measurements of Cosmic Rays Using Balloon Borne Experiments," E. S. Seo, Invited Review Paper for Topical Issue on Cosmic Rays, Astropart. Phys., 39/40, 76-87, 2012.
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BESS
ATIC
ground based Indirect measurements
How do cosmic accelerators work?
Elemental Charge
CREAM
AMS
&
Super TiGER
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• Relative abundances range over 11 orders of magnitude
• Detailed composition limited to less than ~ 10 GeV/nucleon
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CREAM
SOURCES SNRs, shocks Superbubbles
photon emission
acceleration
Interstellar medium
X, γ e-
P He
C, N, O etc. Z = 1- 92
e- γ
gas
P He
C, N, O etc. gas
p
Halo
Disk: sources, gas
escape
B Be
10Be
Synchrotron
Inverse Compton
Bremstrahlung
oπ+π −πe+e-
Chandra
CGRO
Voyager
ACE
AMS BESS
Energy losses Reacceleration
Diffusion Convection
ATIC
B
γ
Exotic Sources: Antimatter
Dark matter etc..
Fermi
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Search for the existence of Antimatter in the Universe
The Big Bang was preceded by vacuum.
Nothing exists in a vacuum.
After the Big Bang there must have been
equal amounts of matter and antimatter.
What happened to the antimatter? Cosmic Rays 6
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• Weakly Interacting Massive Particles (WIMPS) could comprise dark matter.
• This can be tested by direct search for various annihilating products of WIMP’s in the Galactic halo.
χ χ
q q
Indirect Detection
Direct Detection
Part
icle
Col
lider
s
rmv
rGMm 2
2 = rGMv =2
r v
We do not know what 95% of the universe is made of!
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• Original BESS instrument was flown nine times between 1993 and 2002.
• New BESS-Polar instrument flew from Antarctica in 2004 and 2007 – Polar–I: 8.5 days observation – Polar–II 24.5 day observation, 4700 M events 7886 antiprotons detected: no evidence of primary antiprotons from evaporation of primordial black holes.
− +
β−1
Rigidity
Abe et al. PRL, 108, 051102, 2012
Kinetic Energy (GeV)
Ant
ipro
ton
Flux
(m-2
sr-1
s-1 G
eV-1
)
BESS-Polar II Balloon–borne Experiment with a
Superconducting Spectrometer
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BESS-Polar II Balloon–borne Experiment with a
Superconducting Spectrometer
Phys. Rev. Lett., 108, 131301, 2012
X 1/100
x 1/10
6.9x 10-8
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BESS Balloon–borne Experiment with a
Superconducting Spectrometer
Fuke et al. PRL 95, 081101, 2005
• Secondary probability is negligible at low energies due to kinematics
• Any observed almost certainly has a primary origin!
• 95% upper limit (first reported) 1.92 x 10-4 (m2 s sr GeV/n)-1 D
D
D
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Ant
ipro
ton
/pro
ton
Rat
io
Asaoka et al., PRL 88, 051101, 2001
Charge-sign Dependent Solar Modulation
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Voyager 1 in Interstellar Space
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E. C. Stone, ICRC 2013
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From MASS to PAMELA
e- p -
e+ p
He,...
Matter Antimatter Superconducting Spectrometer (MASS) 1989 balloon flight in Canada
GF ~21.5 cm2sr Mass: 470 kg Size: 130x70x70 cm3 Payload for Anti-Matter Exploration and Light-nuclei Astrophysics (PAMELA) satellite Launch 6/15/06
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Payload for Anti-Matter Exploration and Light-nuclei Astrophysics (PAMELA)
“High energy data deviate significantly from predictions of secondary production models (curves), and may constitute the evidence of dark matter particle annihilations, or the first observation of positron production from near-by pulsars.”
Cited > 300 times in ~ 1 yr
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Adriani et al., Nature, 458, 607-609 (2009)
Adriani et al., PRL, 106, 201101 (2011)
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Alpha Magnet Spectrometer
• Search for dark matter by measuring positrons, antiprotons, antideuterons and γ-rays with a single instrument
• Search for antimatter on the level of < 10-9
Launch for ISS on May 16, 2011
Precision Measurements • Magnet 0.9Tm2 •TOF resolution 120 ps •Tracker resolution 10µ •TRD h/e rejection O(102) •EM calorimeter h/e rejection O(104) •RICH h/e rejection O (103)
AMS
Aguilar et al., PRL 110, 141102, 2013
First Result: Precision Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5-350 GeV
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"With AMS and with the LHC to restart in the near future at energies never reached before, we are living in very exciting times for particle physics as both instruments are pushing boundaries of physics,” said CERN Director-General Rolf Heuer.
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Latest AMS Results: Comparison with Models
Accardo et al., Phys. Rev. Lett., 113, 121101, 2014 Aguilar et al., Phys. Rev. Lett., 113, 121102, 2014
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Trac
ker
Flight data
Monte Carlo Simulations
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AMS ~16 billion events per year
Alpha Magnet Spectrometer
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• Beam measurements for 150 GeV electrons show 91% containment of incident energy, with a resolution of 2% at 150 GeV
• Proton containment ~38%
Beam test: electrons Seo et al. Adv. in Space Res., 19 (5), 711, 1997; Ganel et al. NIM A, 552(3), 409, 2005
Flight Data
ATIC Advanced Thin Ionization Calorimeter
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620 GeV Kaluza-Klein particle boosting factor 230
Cited > 200 times in ~ 9 mo
ATIC 1+2, AMS, HEAT BETS, PPB-BETS, Emulsion chambers
ATIC discovers mysterious excess of high energy electrons Chang et al., Nature, 456, 362-365 (2008)
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LAT • Highly granular multi-layer Si
stripTracker (1.5 X0) • Finely segmented fully active
CsI Calorimeter (8.6 X0 ) • Highly efficient hermetic Anti-
Coincidence Detector (ACD)
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2008.06.11
e+
e–
γ
Calorimeter
Tracker
ACD
Abdo, A. A. et al., PRL 102, 181101, 2009
Latronico, Fermi Symposium, 2009
Cited > 150 times in ~ 1 yr
Ahn et al. (CREAM Collaboration) ApJ 714, L89, 2010
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Charge Detector (Charge Z=1-40) 1 Layer of 14 Plastic Scintillators ( 32 x 10 x 450 mm3) Imaging Calorimeter (Particle ID, Direction) Total Thickness of Tungsten (W) : 3 X0 Layer Number of Scifi Belts: 8 Layers ×2(X,Y) Total Absorption Calorimeter (Energy Measurement, Particle ID) PWO 20 mm x 20 mm x 320 mm Total Depth of PWO: 27 X0 (24 cm)
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Launch target JY 2014
450 mm
Shower particles
CALET Calorimetric Electron Telescope
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Cosmic Ray Electron-Synchrotron Telescope (CREST)
• CREST identifies UHE electrons by observing the characteristic linear trail of synchrotron gamma rays generated as the electron passes through the Earth’s magnetic field
- This results in effective detector area much larger than the physical instrument size
• CREST had its first LDB flight over Antarctica in the 2011-2012 season • Upgrade of CREST for ULDB operation in plan.
Expected result: 100-day CREST exposure
CREST Detector – A 2 x 2 m array of 1600 1” diameter BF2 crystals.
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Cherenkov
dE/dx TRD
LORENTZ FACTOR γ
SIG
NA
L (a
rb. u
nits
)
ENERGY RESPONSE: Acrylic Cherenkov Counter (γ < 10) Specific Ionization in Gas (4 < γ < 1000) Transition Radiation Detector (γ > 400)
Transition Radiation Array for Cosmic Energetic Radiation (TRACER)
2 m
1.2 m
• 2003 ANTARCTICA 14 days OXYGEN (Z=8) to IRON (Z=26)
• 2006 SWEDENCANADA 4.5 days BORON (Z=5) to IRON (Z=26)
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Seo et al. Adv. in Space Res., 33 (10), 1777, 2004; Ahn et al., NIM A, 579, 1034, 2007
• Transition Radiation Detector (TRD) and Tungsten Scintillating Fiber Calorimeter
- In-flight cross-calibration of energy scales • Complementary Charge Measurements
- Timing-Based Charge Detector - Cherenkov Counter - Pixelated Silicon Charge Detector
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• The CREAM instrument has had six successful Long Duration Balloon (LDB) flights and have accumulated 161 days of data. – This longest known exposure for a single
balloon project verifies the instrument design and reliability.
CREAM Cosmic Ray Energetics And Mass
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Balloon Flights in Antarctica Offer Hands-On Experience CREAM has produced >12 Ph.D.’s
The instruments are for the most part built in-house by students and young scientists, many of them currently working in the on-campus laboratory.
Seo’s lab at UMD
Seo’s lab at UMD
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Instruments are fully recovered, refurbished & reflown.
Typical duration: ~1 month/flight
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Elemental Spectra over 4 decades in energy
Distribution of cosmic-ray charge measured with the SCD. The individual elements are clearly identified with excellent charge resolution. The relative abundance in this plot has no physical significance
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Yoon et al. ApJ 728, 122, 2011; Ahn et al., ApJ 715, 1400, 2010; Ahn et al. ApJ 707, 593, 2009
Excellent charge resolution from SCD PAMELA Results (Sparvoli, ISCRA 2012)
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γ < 200 GeV/n = 2.77 ± 0.03 γ > 200 GeV/n = 2.56 ± 0.04
CREAM C-Fe
He
γCREAM = 2.58 ± 0.02
γAMS-01 = 2.74 ± 0.01
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PAMELA (Adriani et al., Science 332, 69, 2011)
(Ahn et al., ApJ 714, L89, 2010)
Yoon et al. ApJ 728, 122, 2011; Ahn et al. ApJ 714, L89, 2010
CREAM-I γP = 2.66 ± 0.02 γHe = 2.58 ± 0.02
It provides important constraints on cosmic ray acceleration and propagation models, and it must be accounted for in explanations of the electron anomaly and cosmic ray “knee.”
AMS-02 (Choutko et al., #1262; Haino et al. #1265, ICRC, Rio de Janeiro, 2013)
CREAM spectra harder than prior lower energy measurements
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Yuan & Bi, Phys. Lett. B, 727, 1, 2013 & Yuan et al. arXiv:1304.1482, 2013
Taking into account the spectral hardening of elements for the (AMS/PAMELA/ATIC/FERMI) high energy e+ e- enhancement
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T. K. Gaisser, T. Stanev and S. Tilav, Front. Phys. 8(6), 748, 2013
S. Tilav’s presentation, TeV Particle Astrophysics, Irvine, CA , 26-29 August 2013
CREAM solves the puzzle with the knee and beyond
Acceleration limit: Emax_z = Ze x R = Z x Emax_p, where rigidity R = Pc/Ze
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Cosmic Rays Eun-Suk Seo
Cosmic Ray Propagation
Consider propagation of CR in the interstellar medium with random hydromagnetic waves.
Steady State Transport Eq.:
The momentum distribution function f is normalized as where N is CR number density, D: spatial diffusion coefficient, σ: cross
section… Cosmic ray intensity Escape length Xe Reacceleration parameter α
E. S. Seo and V. S. Ptuskin, Astrophys. J., 431, 705-714, 1994.
{ } kjk
jkjj
ionjj
j
e
j Im
QI
dxdE
dEdI
mXI
∑<
+=
+++
σρ
ασ
0,
...
∑<
+=
∂∂
+∂
∂
∂∂
++∂
∂
∂∂
∂jk
jkjjionj
jjj
jj Sqfdt
dppppp
fKp
ppfv
mzf
Dz ,
22
22
11σρ
fpdpN ∫= 2
)()( 02 pfpAEI jjj =
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• Measurements of the relative abundances of secondary cosmic rays (e.g., B/C) in addition to the energy spectra of primary nuclei will allow determination of cosmic-ray source spectra at energies where measurements are not currently available
• This first B/C ratio at such high energies will distinguish among propagation models
What is the history of cosmic rays in the Galaxy? Ahn et al. (CREAM collaboration) Astropart. Phys., 30/3, 133-141, 2008
δ−∝ RX e
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ISS-CREAM: CREAM for the ISS
• Building on the success of the balloon flights, the payload is being transformed for accommodation on the ISS (NASA’s share of JEM-EF). − Increase the exposure by an order of magnitude
• ISS-CREAM will measure cosmic ray energy spectra from 1012 to >1015 eV with individual element precision over the range from protons to iron to:
- Probe cosmic ray origin, acceleration and propagation. - Search for spectral features from nearby/young sources, acceleration
effects, or propagation history.
Mass: ~1400 kg Power: ~ 550 W Nominal data rate: ~350 kbps
To be installed on the ISS in 2015 by Space X JEM-EF #2
E. S. Seo et al, Advances in Space Research, 53/10, 1451, 2014
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CREAM Instrument
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Silicon Charge Detector (SCD) • Precise charge measurements with
charge resolution of ~ 0.2e • 4 layers of 79 cm x 79 cm active
area (2.12 cm2 pixels)
Top/Bottom Counting Detector (T/BCD) • Plastic scintillator
instrumented with an array of 20 x 20 photodiodes for e/p separation
• Independent trigger
Calorimeter • 20 layers of alternating
tungsten plates and scintillating fibers
• Determines energy • Provides tracking and
trigger
Boronated Scintillator Detector (BSD) • Additional e/p separation by
detection of thermal neutrons
Ahn et al., NIM A, 579, 1034, 2007; Anderson et al., Hyun et al., & Seo et al. 33rd ICRC, 2013
Carbon Targets • Induces hadronic interactions
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Data Flow & Science Operations
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CREAM
TDRSS
White Sands, NM
Command &
Playback Request
Data Verification Event Display
Data
Data relay
Real-time data
Playback data
Raw Data
Data Monitoring
Commands
Science Operation Center (UMD)
Data
Plots
Data Backup, Archive &
Processing
Data Server
Level-0 data Level-1 data Level-2 data
Web Server Data Distribution
Research Data Center (UMD)
Huntsville Operations Support Center (MSFC)
• Payload Operations and Integration Center (POIC) Maintains databases for commands and telemetry
• Holds recorded data for 2 yrs
Ku band High rate 10 Mbps (down)
S band Low rate (up/down) 30 kbps monitoring 1 kbps cmd
Ethernet & MIL-STD-1553
Software Toolkit for Ethernet Lab-Like Architecture (STELLA)
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ISS-CREAM takes the next major step
• The ISS-CREAM space mission can take the next major step to 1015 eV, and beyond, limited only by statistics.
• The 3-year goal, 1-year minimum exposure would greatly reduce the statistical uncertainties and extend CREAM measurements to energies beyond any reach possible with balloon flights.
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• ISS-CREAM
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Cosmic Ray Observatory on the ISS
AMS Launch May 16, 2011
ISS-CREAM Sp-X Launch 2015
JEM-EUSO Launch Tentatively planned for >2018
CALET on JEM HTV Launch 2015
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http://cosmicray.umd.edu
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Thank you!
Slide Number 1Discovery of Cosmic RaysSlide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Voyager 1 in Interstellar SpaceFrom MASS to PAMELAPayload for Anti-Matter Exploration and Light-nuclei Astrophysics (PAMELA)Slide Number 15Slide Number 16Latest AMS Results: Comparison with ModelsSlide Number 18Seo et al. Adv. in Space Res., 19 (5), 711, 1997; Ganel et al. NIM A, 552(3), 409, 2005Slide Number 20Slide Number 21Slide Number 22Cosmic Ray Electron-Synchrotron Telescope (CREST) Slide Number 24Slide Number 25Balloon Flights in Antarctica Offer Hands-On Experience�CREAM has produced >12 Ph.D.’s Slide Number 27Slide Number 28Slide Number 29CREAM solves the puzzle with the knee and beyondCosmic Ray PropagationWhat is the history of cosmic rays in the Galaxy?ISS-CREAM: CREAM for the ISSCREAM InstrumentData Flow & Science Operations ISS-CREAM takes the next major stepSlide Number 37Slide Number 38