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The past 5 months when I was in SSL @ UCB…

The past 5 months when I was in SSL @ UCB…. Jeng-Lun Chiu (Alan) Department of Physics, NTHU / SSL, UCB 2006/12/19. Outline. Introduction to NCT Data & simulation formats Charge sharing & Energy Loss Mgeant & MEGAlib Image Reconstruction PIXON algorithm Future Work. NCT.

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The past 5 months when I was in SSL @ UCB…

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  1. The past 5 months when I was in SSL @ UCB… Jeng-Lun Chiu (Alan) Department of Physics, NTHU / SSL, UCB 2006/12/19

  2. Outline • Introduction to NCT • Data & simulation formats • Charge sharing & Energy Loss • Mgeant & MEGAlib • Image Reconstruction • PIXON algorithm • Future Work

  3. NCT Nuclear Compton Telescope • Sources: Nuclear line emission & polarization • Energy-band: Soft gamma-ray (0.2-10 MeV) & hard X-ray (8-100 keV) • Targets: GRB (monitor), solar flares, TGFs (Terrestrial Gamma-ray Flashes), • Interest: 511-keV galactic emission line, emission and acceleration mechanisms in the magnetospheres of gamma-ray pulsars, sources of 26Al as being core-collapsed supernovae or Wolf-Rayet stars • Scientific goal: (1) MeV gamma-ray all-sky survey, (2) hard X-ray all-sky survey, (3) Gamma-Ray Bursts (GRBs), (4) cosmic rays, (5) Active Galactic Nuclei (AGN), (6) supernovae and supernova remnants, (7) X-ray binaries, (8) Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs), (9) gamma-ray pulsars, (10) galactic 0.511-MeV lines, (11) solar flares, and (12) Terrestrial Gamma-ray Flashes (TGFs) • Calibration Lines (keV): 59.5 (241Am); 81.0, 356 (133Ba); 122, 136 (57Co); 662 (137Cs); 1173, 1333 (60Co). Pre-flight in 2005 Present status

  4. Nuclear Compton Telescope ( M. E. Bandstra, 2006 IEEE ) ( E, x, y, z, t ) ( S. E. Boggs, CIS workshop 2005 @ NTHU )

  5. Procedure for analysis mgeant sharexint reconstruct IDL Simulation .out [9] .txt[7] .dat[15] .gif (..etc) (bin) (bin) Data .str .bin wrfile prbin “Readme.txt” by J. D. Bowen, Jul 14, 2006

  6. Simulation(/data) formats Event number Multi. # / order veto Energy X Y Z DSP

  7. Event number Event clock Sharing flag - X Sharing flag - Y Multi. # | order E (DC) E (AC) X-strip Y-strip DSP ……………………………

  8. Energy loss & charge sharing (AC) by Zong-Kai Liu

  9. Energy loss & charge sharing (DC) by Zong-Kai Liu

  10. Energy loss & charge sharing W. Coburn, et al., 2002, SPIE

  11. Procedure for analysis mgeant sharexint reconstruct IDL Simulation .out [9] .txt[7] .dat[15] .gif (..etc) (bin) (bin) Data .str .bin wrfile prbin “Readme.txt” by J. D. Bowen, Jul 14, 2006

  12. version, format, beam, spec, ( hadronic inter. ) mgeant Kine, Trig, Beam, Spec, Threshold, output filename, etc.. Information on the header of output file ..etc others... usrinp.F Imakefile input.dat ( simulation parameters ) media.med ( define material types ) gmake setup.geo ( creation of geometries ) material.mat ( define materials ) mgeant excutable GEANT3 INTER BATCH SCAN2 output Interface for “Geant3” simulation http://astrophysics.gsfc.nasa.gov/astroparticles/programs/mgeant/

  13. MEGAlib picture MEGAlib: completely object-oriented (written in “C++ & ROOT”) Geomega:providing geometry & detector description module Unsequenced hits Compton, Pair, etc.. Sivan Simulation verification Geant3 GMega Geant3 simulation fits Responsegenerator Convert- MGGPOD MGGPOD fits Mimrec High-level data analysis & Image reconstruction Revan Event Reconstruction sim tra Geant4 Cosima Geant4 simulation fits evta GeoMega – Geometry for Mega Revan – Real event analyzer Mimrec – Mega image reconstruction ( http://www.mpe.mpg.de/MEGA/megalib.html ) Detector (real data) MEGAlyze Data acquisition & calibration bin A. C. Zoglauer, 2006

  14. Image Reconstruction • Instrumental and atmospheric limitations  blurring of the image • But deblurring (deconvolution) techniques tend to amplify the noise ( D: data ; H: PSF ; I: image ; N: noise )

  15. PIXON - Basic Concepts • Information theory: the most efficient (minimal description) model of the signal also does the best job of separating it from noise  Pixon method demands minimum complexity, or Algorithmic Information Content (AIC)  It selects the smallest number of basis functions that still adequately fit the data. Innovation: Pixon-element (each basis function)  minimum parameterization PIXON:(1). A picture element (2). A fundamental unit of information in the image The smallest groupings of signal warranted by the quality of the data, and they are fundamental and indivisible units of picture information. An image’s pixon represent the minimum set of degrees of freedom necessary to describe the image. (PP93)

  16. Solution: Pixon method provides a solution: (1) It assigns a priori probabilities to different signal models, so a function that zigzags through noisy data has low probability, while a smooth function has a high a priori probability. (2) In Bayesian fashion, it maximizes not the usual maximum likelihood of the data, given the model, but the product of that likelihood and the prior probability of the model. Benefit: (1) Increase the spatial resolution by factors of several (2) Increase the sensitivity to low contrast sources by orders of magnitude (3) Ensure robust rejection of spurious sources

  17. PIXON

  18. Quick PIXON

  19. Summary • Data formats and processing procedures • Simulation – mgeant to geant3 • MEGAlib package • PIXON algorithm • C++ for object-oriented programming • LM-ML algorithm • GSE codes… Starting…

  20. Future Work • Image reconstruction – PIXON • Ground Support Equipment (with Mark) • Pointing & Aspect (with Mark) • Calibrations (all) • Data archiving (with Andreas) • Analysis Software (Andreas leads all)

  21. Reference • W. Coburn, S.E. Boggs, S. Amrose, R.P. Lin, M.T. Burks, M. Amman, P.N. Luke, N.W. Madden, and E.L. Hull. Results of charge sharing tests in a Ge-strip detector. In 2001 IEEE Nuclear Science Symposium Conference Record. IEEE, New York, NY, Vol. 1, pp. 226-229 (2002). • W. Coburn, S. Amrose, S.E. Boggs, R.P. Lin, M.S. Amman, M.T. Burks, E.L. Hull, P.N. Luke, and N.W. Madden. 3D positioning germanium detectors for gamma-ray astronomy. In SPIE-Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, Bellingham, WA, Vol. 4784, pp. 54-63 (2002). • J.D. Bowen, M.E. Bandstra, S.E. Boggs, W. Coburn, C.B. Wunderer, R.P. Lin, M. Amman, P.N. Luke, M.T. Burks, W. Craig, N.W. Madden, D.M. Smith, P. von Ballmoos, P. Jean. Pre-flight calibration of the prototype Nuclear Compton Telescope. In SPIE-Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, Bellingham, WA, Vol. 6266, pp. (2006). • Andreas Zoglauer, "First Light for the Next Generation of Compton and Pair Telescopes", TU Munich, 12/2005 • Talks in CIS workshop @ NTHU, Nov. 15-17, 2005 • Talks in NCT workshop @ NTHU, Sep. 11-12, 2006 • http://universe.gsfc.nasa.gov/astroparticles/programs/mgeant/( mgeant ) • http://www.mpe.mpg.de/MEGA/megalib.html( MEGAlib ) • Piña R. K. & Puetter R. C., 1993, PASP, 105, 630 • R. C. Puetter, Ann. N.Y Acad. Sci., 808, pp. 160-183 (1997). • http://casswww.ucsd.edu/personal/puetter/pixonpage.html(The Pixon PAGE in UCSD) • http://www.pixon.com/brochure.html(The PIXON method @ www.pixon.com)

  22. ~ Thank you ~

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