Laboratory Astrophysics in Taiwanstudying properties of cosmic ray showers using NSRRC 1'5 GeV elect

1
Laboratory Astrophysics in Taiwan-studying
properties of cosmic ray showers using NSRRC 1.5
GeV electron beam
KAW4 2006

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

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Outline

• 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

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General Features of LabAstro-Using Lasers and
Particle Beams as Tools -

• 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

P. Chen, Workshop on laboratory astrophysics
using high intensity particle and photon beams.
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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
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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 E1020 eV.
• This discrepancy can be possibly accounted for
  by a systematic difference in the energy scale
  (25)

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The Detection of UHECR
Air Fluorescence Detector HiRes
Hybrid Auger
AGASA Detector
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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
processmodel independent!

• How well do we know the fluorescence efficiency?
• Can the fluorescence yield accurately reconstruct
  
• the longitudinal profile Ne(X)?

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SLAC E-165 ExperimentFluorescence in Air from
Showers (FLASH)28.5 GeV e- beam
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The thin target Experiment Layout
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The Existing Air Fluorescence Yield
Measurementswithout Showers

• 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

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Thick Target apparatus
Ion chamber
Available shower depth 2,4,6,8,10,14 radiation
lengths
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Universal electron energy distribution in
different shower ages
F. Nerling et al., astro-ph/0506729

• The shower age S3X/(X2Xmax) 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/bunch1019 eV.

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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
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Studying Cherenkov light from air showers with
NSRRC 1.5 GeV e- beam

• 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

(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
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Motivation

• 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.

Page 12
Page 30
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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
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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
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Exp
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Experimental Platform
Each block contains 1/3 R.L.
Lateral Profile
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The CCD quantum efficiency is not uniform
Fluorescence contributions arise between 300 nm
and 400 nm.
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CCD Backgroundbeam off
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We have also subtracted the background with beam
on and the chamber in vacuum.
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2.3 r.l. Shower maximum
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5 r.l. Shower maximum
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Preliminary
Shower maximum occurs at 2.3 r.l.
Counts at 0 r.l. subtracted
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GEANT4 simulations
e- e ?
One incident electron
Shower maximum
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One incident electron
15 blocks
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Shower longitudinal profiles _at_4.5?106 simulations
Shower maximum occurs near 2.3 r.l.
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Preliminary
A consistency check
Separately normalized to respective total
counts/event
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The Cherenkov photon yield verse particle energy
The simulated longitudinal profile has to be
folded with Cherenkov photon yield.
Back to 15
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Geant 4 simulation with Cherenkov photons
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?The fluorescence contribution has to be
subtracted from the datausing simulations
tested by FLASH thick target experiment. ?Angular
distributions of Cherenkov photons will be
studied as well.
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Concluding Remarks

• 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!

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Result Fluorescence Spectrum
22nd Texas Symposium on Relativistic Astrophysics
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Preliminary
Statistics low at low and high radiation
lengths --to be improved