1 / 19

Report of the Working Group Calibration, Monitoring and Site

Report of the Working Group Calibration, Monitoring and Site. Conveners: M. Teshima, B. Khélifi Members: J. Cortina, R.G. Lopez, M. Gaug, E. Giraud, R. Mirzoyan, P. Mayumdar, M. Mori, V. Mitev, M. Panter, A. Sillampaä, S. Swordy, J.-P. Tavernet, G. Vasileiadis, S. Wagner

lydie
Télécharger la présentation

Report of the Working Group Calibration, Monitoring and Site

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Report of the Working GroupCalibration, Monitoring and Site Conveners:M. Teshima, B. Khélifi Members:J. Cortina, R.G. Lopez, M. Gaug, E. Giraud, R. Mirzoyan, P. Mayumdar, M. Mori, V. Mitev, M. Panter, A. Sillampaä, S. Swordy, J.-P. Tavernet, G. Vasileiadis, S. Wagner Activity:5 phone-conferences, email exchanges  Draft for the Letter of Intend

  2. Calibration and atmospheric monitoring

  3. What to calibrate and to monitor? • Atmospheric monitoring: Extinction coefficient • Optical components: Mirrors, funnels, photocathods • Camera electronics: Gain, flat fielding, usable pixels, …  Conversion factor: # ADC per Cherenkov photons B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  4. Camera performances • Functioning parameters of the cameras not treated here, Just the camera characteristics used for the data analysis • Channel noise • From electronics • From Night Sky Background  No need of specific instrumentation • Conversion factor: #ADC per photoelectron • Components: efficiency of the integration window, electronic gains, Photodetector internal gain  LED flashers B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  5. Camera performances (2) • Flat fielding • Different detection efficiency between channels Funnels, photocathods • LED flashers • Usable channels • Malfunctioning reasons depend on camera technology • Big efforts should be done to their identifications  No need of specific instrumentation B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  6. Optical components • Involved components: Mean Photocathod efficiency, mean funnel and mirrors efficiency • This global efficiency allows an absolute calibration  Use of muon rings B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  7. Atmospheric monitoring • Standard weather conditions Meteo station • Water vapor and cloud monitoring Infrared radiometers B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  8. Atmospheric monitoring (2) Results of LIDAR simulations V. Mitev LIDAR TRmodel = 0.9498 TRmeas = 0.9508 (9-10.4 km) Cirrus cloud TRmodel = 0.5836 TRmeas = 0.5830 (3-5 km) Troposphere/Desert Dust 60° Dust layer • Estimation of the optical depth above telescopes: • Photometric telescope • Continuous monitoring • Cross-check with LIDAR • Atmosphere profile • Radiosondes: seasonal variations Transmissometer (transmissivity at the ground layers) B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  9. Conclusions • Draft of the WG has been submitted (8 pages) • For the Design Study (Working Package 12): • Big efforts on the LIDAR technique to routinely correct for atmosphere variations  Closer work with atmospheric physicists • Efforts to measure and to use the seasonal atmospheric profile measured by radiosondes • Apply and test these atmospheric corrections to the data analysis B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  10. Candidates for CTA sites

  11. Criteria of selection • Altitude above 1.5 km • Small cloud coverage: good nights > 60% • Atmosphere transparent and dry • Latitude around +30° N and -30° S • Facility of site access • Political stability • … B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  12. CTA North B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  13. CTA South B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  14. Known Cherenkov sites MACE CANGAROO III • Thomas Highlands, Namibia • Tenerife Teide, La Palma • Himalaya Hanle (India) • Woomera (Australia) • Good quality possible sites • Useful for comparisons B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  15. Sites for optical astronomy La Silla Paranal • Chilean sites • La Silla - Atacama desert • Paranal – 12 km from coast (VLT) • La Montura • … • High quality atmospheric conditions • Between 2.000 and 3.000 m a.s.l. • Caution: available area B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  16. Exploration of new sites Chajnantor Archibarca Catamarca Erasmus • Based on satellite survey Eramus  Staden, 2001 • Cloud cover, water vapor • Data over 5 years • 5-10 candidates in Northern Argentina • Good fraction of clear nights • Altitude above 3.500 m a.s.l. • Very large area • Can be isolated clear nights 1st half B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  17. Exploration of new sites (2) S 24° 32.118’ W 67° 4.363’ 3722 m a.s.l. POCITOS N Chajnantor Sus7052 • On site measurements • Telescope: Newton with CCD cam. • U, V, B Antonio Pocitos Tolar G. Archibarca Pocitos ALMA 74% Catamarca 67% Plateau below ALMA site 60% La Silla Tolar Grande Erasmus • On site explorations (12-2006) • E. Giraud, G. Vasileiadis, M. Gaczarzyk, T. Schweizer, A. Rovero, E. Colombo • 4 sites visited clear nights 1st half B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  18. Conclusions • Big activity of the WG members to identify candidates literacy, reports on web, personal contacts, visits, measurements,… • Draft of the WG has been submitted (23 pages) • Good starting point for the Design Study Even if Northern sites are so few and other possibilities have not yet investigated (e.g. South Utah) • For the Design Study (Working Package 4): • Use long-term data from satellites and in-situ measurements • Identify site facilities (for the access and the building phase) B. Khélifi WG Calibration/Monitoring/Site Paris, 02/03/2007

  19. Thank you to all for your contributions

More Related