1. Report of the Working Group Calibration, Monitoring and Site Conveners: Conveners: M. Teshima, B. Khélifi Members: 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: Activity: 5 phone-conferences, email exchanges  Draft for the Letter of Intend

2. Calibration and atmospheric monitoring

3. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 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 # ADC per Cherenkov photons

4. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 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

5. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 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

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

7. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 Atmospheric monitoring Standard weather conditions Meteo station Water vapor and cloud monitoring Infrared radiometers

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

9. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 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

10. Candidates for CTA sites

11. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 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 …

12. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 CTA North

13. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 CTA South

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

15. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 Sites for optical astronomy 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 La SillaParanal

16. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 Archibarca Catamarca Chajnantor 1st half Exploration of new sites 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 Erasmus

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

18. B. KhélifiWG Calibration/Monitoring/SiteParis, 02/03/2007 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)

19. Thank you to all for your contributions