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大気モニタ R&D Atmospheric Monitoring for TA

大気モニタ R&D Atmospheric Monitoring for TA. テレスコープアレイ計画 63. M Chikawa, J Kaku ， T Benno, T Nishikaze Kinki Univ. N Hayashida ICRR and TA group. 30th March 2004 : JPS @ 福岡. I 0 ∝E. I. Air Fluorescence. Atmospheric structure.

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大気モニタ R&D Atmospheric Monitoring for TA

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  1. 大気モニタR&DAtmospheric Monitoringfor TA テレスコープアレイ計画63 M Chikawa, J Kaku， T Benno, T Nishikaze Kinki Univ.N Hayashida ICRR and TA group 30th March 2004 : JPS @ 福岡

  2. I0∝E I Air Fluorescence

  3. Atmospheric structure change its transmittance in spatial and vary with time → important to know its structure and time variation → back scatt., side scatt., sunphoto meter etc. z atmosphere scattering process Rayleigh(molecule) depends on ρ(z) Mie(aerosol) depends on aerosol wide and local area time density ρ(z) cloud aerosol dust, vapour, mist, fog wind

  4. Estimate of Mie effect near ground surface (simulation by Ogio(TIT)) EAS generated events = 100, arrival zenith angle : uniform energy =10^20 eV (fixed) Fluorescence light 3km TA without anycut for the data cut data w/i 3km above ground

  5. Atmospheric Monitoring - lidar system : transparency of atmosphere as far as possible fluorescence light correction factor : I ⇒I0∝EEAS  feasibility study at AKENO suggests aspect to determine extinction coefficient by 20km : steerable Lidar How to… shoot, DAQ, analyze，and calibrate, etc. - cloud monitoring : fiducial volume  IR(infra red) camera Observe all sky region → IR camera + convex mirror - astro dome  will be settled on the roof of each three stations in order to install Liar systems These are the issues that Japanese Atmospheric WG is going to do for TA.

  6. back scattering(LIDAR method)& side scattering(phase function method) θ=180 0<θ<180 θ Laser

  7. Horizontal Measurement

  8. Assumption for analysis To evaluate the extinction coeff. from Lidar data, Simple & convenient assumption for structure of atmosphere is applied. 1, only Rayleigh Scattering>10km Assume this behaviour, develop a new Lidar system Inclined Laser shots 2, Atmosphere Almost Uniform In Horizontal direction Lidar 3, Measure Horizontal: Rayleigh+Mie

  9. Typical examples

  10. Akeno data 15/Oct/2003 • Lidar exp’t at Akeno • Typical sample of good results • Corrected intensity of scattered light PxR2 vs. light path length

  11. Extinction length vs. height from ground surface horizontal

  12. Lidar exp’t R&D @ Akeno w/ steerable system Mirror diameter 15cm, laser power 5mJ 3-dimension measurement : ≦10km in vert. & horiz. condition α ± Δα fine 0.0639 ± 0.0005 hazy 0.1394 ± 0.0005 0.1645 ± 0.0010 cloudy 0.3254 ± 0.0016 ⇒ should be measured far distance ～20km solution : install larger mirror, higher power laser

  13. 1/2 parameters of the lidar system required specification for Lidar system to determine extinction coeff. approx. 20km with few % error Off-line analysis : analyze Lidar data from each station independently

  14. New LIDAR system

  15. 透過率測定 Energy meter telescope Energy meter T1=4752±290 T0=128940±798 補正板＋主鏡＋副鏡 R = T1/T0 = 0.17±1% Nd:YAG Laser 5 mJ / pulse

  16. IR Camera Cloud monitoring Sensitivity : 8 -14μm -20 ゜ ～ 300 ゜ FOV：25.8゜（H）×19.5゜（V） 320×236 pixel digital value  temperapure

  17. IR Camera Cloud monitoring • IR camera on a steerable system: Akeno Lidar system • IR camera use 2-dimensional cloud monitor and measure distance by Lidar  3-dimensional cloud monitoring • option : VTR(visible light) for all-sky waether monitor IR camera on AKENO lidar system

  18. differential coeff. threshold cut digitize: B&W calculates of edge of the cloud

  19. Astro dome • settle an astrodome nearby the telescope station on the ground install a new LIDAR system inside astrodome

  20. Discussion • Range of extinction length : 20km  may be OK, but enough?  feasibility study at Akeno supports 20km measurement: realistic limit value for our Lidar system  during laser shooting to measure  might be serious problem for DAQ of E>1018eV, EAS ratefrom AGASA ★ext. lengthα has largedependence of the empirical parameter k (=0.6 to 1.3) in the model 　　  feasibility study to measure absolute light intensity by PMT free from model dependence for Rayleigh scattering • LIDAR : steerable system  need to establish robust system using commercial product • Astro dome : settle on the ground nearby the TA station • IR camera  all sky monitoring and off-line data analysis can be available

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