Download Candidates for CTA sites

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
Activity: 5 phone-conferences, email exchanges
 Draft for the Letter of Intend
Calibration and atmospheric
monitoring
What to calibrate and to monitor?
• Atmospheric monitoring:
Extinction coefficient
• Optical components:
Mirrors, funnels,
photocathods
 Conversion factor:
# ADC per Cherenkov photons
B. Khélifi
• Camera electronics:
Gain, flat fielding,
usable pixels, …
WG Calibration/Monitoring/Site
Paris, 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
B. Khélifi
WG Calibration/Monitoring/Site
Paris, 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
B. Khélifi
WG Calibration/Monitoring/Site
Paris, 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
B. Khélifi
WG Calibration/Monitoring/Site
Paris, 02/03/2007
Atmospheric monitoring
• Standard weather conditions
Meteo station
• Water vapor and cloud monitoring
Infrared radiometers
B. Khélifi
WG Calibration/Monitoring/Site
Paris, 02/03/2007
Atmospheric monitoring (2)
• Estimation of the optical depth above telescopes:
LIDAR
Transmissometer
(transmissivity at the ground layers)
Results of LIDAR simulations
V. Mitev
• Photometric telescope
Cirrus cloud
– Continuous monitoring
TRmodel = 0.5836
– Cross-check with TRmeas
LIDAR = 0.5830
TRmodel = 0.9498
TRmeas = 0.9508
(9-10.4 km)
(3-5 km)
• Atmosphere profile
Troposphere/Desert Dust
– Radiosondes: seasonal
variations
60°
B. Khélifi
Dust layer
WG Calibration/Monitoring/Site
Paris, 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
B. Khélifi
WG Calibration/Monitoring/Site
Paris, 02/03/2007
Candidates for CTA sites
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
CTA North
Sites - Parameters
Location (long itud e)
Location (Lattitud e)
Heig ht
R ig id ity cutoff
Land owner
Av aliab le flat area
Typ e of g round
Access from nearb y City (hrs)
Access from EU (hrs)
Nearest international airp ort
17.86 W
28.75 N
2200 m
IAC
300x300m2
soil, rocks
1
5
La Palma
Clear nig hts (sp ectroscop ic nig ht)/yr
Photometric nig hts/yr
Days with g round fog /yr
Lig ht p ollution
75%
Av summer d ay /nig ht temp
Av winter d ay / nig ht temp
# of d ays with wind v el (>10m/s)
# of Cyclones and Tornad es / 10yr
Annual p recip itation(mm)
Av summer humid ity
Av winter humid ity
Av snow d ep th
M aximum snow d ep th last 10yr
17
2
13 %
Electric p ower line
W ater
Hand y/M ob il serv ice
Distance to hig h b and wid th internet
Sites - Parameters
B. Khélifi
2400 m
112.5 W
37.5 N
1800-3000
M una K ea
78.96E
32.78N
4300m
State Ind ia G ov t
v ast
2x2km2 10x10 km2
soil, rocks soil,rocks
6-7 hrs
2
1
21-22
19
5
Delhi
S.L.C.
Tenerife
260
190
low
low
low
v ery low
20/10-15C
-5/-15C
19%
nil
2mm
15-45%
10-40%
10-40%
40-60%
Yes
Yes
Yes
0
No
Yes
No
0
0
0
90
260K m
260K m
75K m
Nearest hotels or lod g e (mins)
Nearest restaurants (mins)
Nearest hosp itals (mins)
Dang erous animals
End emic d isease
Scientific facilities
Political stub ility
CTA-North
Hanle
So. Utah
Teid e
La Palma
no
no
ENO
Stab le
La Palma
no
no
IAO
yes
no
no
ENO
Stab le
Teid e
So. Utah
Hanle
WG Calibration/Monitoring/Site
M una K ea
Paris, 02/03/2007
CTA South
Sites - Parameters
Location (long itud e)
Location (Lattitud e)
Heig ht
R ig id ity cutoff
Land owner
Av aliab le flat area
Typ e of g round
Access from nearb y City (hrs)
Access from EU (hrs)
Nearest international airp ort
Clear nig hts (sp ectroscop ic nig ht)/yr
Photometric nig hts/yr
Days with g round fog /yr
Lig ht p ollution
Av summer d ay /nig ht temp
Av winter d ay / nig ht temp
# of d ays with wind v el (>10m/s)
# of Cyclones and Tornad es / 10yr
Annual p recip itation(mm)
Av summer humid ity
Av winter humid ity
Av snow d ep th
M aximum snow d ep th last 10yr
W oomera
Alma
16.5 E
23.26 S
1800 m
136.786 E
31.099 S
160 m
67.75W
23.00 S
4600-5100m
70.41 W
24.66 S
2635 m
70.73 W
29.25 S
2200-2400m
68.46 W
24.32 S
4300m
69.05 W
24.25 S
3100m
g v mnt
500kx300k
Soil
5
25
Ad elaid e
State
Vast
Soil, rocks
2
16+3
Calama
Chile
Nearb y summits
Soil, rocks
2
16+3
Antofag asta
Chile
Low slop es
Soil, rocks
2
16+2
La Serena
?
Larg e
?
Too small
4?
16+3
Antofag asta
3?
16+3
Antofag asta
72 %
<80 %
>63 %
Some
None
90 %
75-80 %
82 %
62 %
Some
Very low
0.9xParanal?
0.9xParanal?
Paranal?
Paranal?
5/0C
-5/-15C
D:freq uent N:rare
Days>25m/s each year
14C
11C
25 %
0
<10 mm
10-25 %
<10 %
5 mm
2-3
9.5
63 %
54 %
None
19
11
10 %
188 mm
B. Khélifi
30-50 %
10-30 %
Yes
Yes
Yes
10km
Nearest hotels or lod g e (mins)
Nearest restaurants (mins)
Nearest hosp itals (mins)
Sites - Parameters
27
11
25-50 %
Electric p ower line
W ater
Hand y/M ob il serv ice
Distance to hig h b and wid th internet
Dang erous animals
End emic d isease
Scientific facilities
Political stub ility
CTA-South
Paranal-La M ontura (ch)
La Silla-Viscachas (ch) El Huesco (ch)
HESS
15
15
15
HESS
no
no
CANG AR OO
HESS
W oomera
40km
40km
200km,1500km
Alma
None
15 %
0
Site D (ch)
None
6C
-8C
1-9km/s
?
<15mm
30-50 %
5-15 %
?
14C
5C
0-9km/s
?
<10mm
25-30%
10-15%
?
No
Yes
?
?
?
?
200km
200km
~ 200km, ~ 1500km
ESO or 200km
ESO or 200km
~ 200km, ~ 700km
250km
250km
250, 1500km
220km
220km
220, 1500km
No
No
ESO
Stab le
No
Chag as?
ESO
Stab le
No
No
No
Stab le
No
Stab le
VLT
La Silla
El Huesco
Site D
WG Calibration/Monitoring/Site
Paris, 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
B. Khélifi
WG Calibration/Monitoring/Site
Paris, 02/03/2007
Sites for optical astronomy
La Silla
• 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
Exploration of new sites
• Based on satellite survey
Erasmus
Eramus  Staden, 2001
– Cloud cover, water vapor
– Data over 5 years
 Good fraction of clear nights
 Altitude above 3.500 m a.s.l.
 Very large area
 Can be isolated
B. Khélifi
clear nights
• 5-10 candidates in Northern
Argentina
Chajnantor
WG Calibration/Monitoring/Site
Archibarca
Catamarca
1st half
Paris, 02/03/2007
Exploration of new sites (2)
• On site explorations (12-2006)
• On site measurements
− Telescope: Newton with CCD cam.
− U, V, B
POCITOS
Pocitos
74%
N
67%
60%
La Silla
ALMA
clear nights
– E. Giraud, G. Vasileiadis, M. Gaczarzyk, T.
Schweizer, A. Rovero, E. Colombo
– 4 sites visited
Erasmus
S 24° 32.118’
3722 m a.s.l.
Plateau below
ALMA site
Chajnantor
Sus7052
Antonio
Pocitos
Archibarca
Tolar G.
W 67° 4.363’
Catamarca
Tolar Grande
B. Khélifi
WG Calibration/Monitoring/Site
1st half
Paris, 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)
B. Khélifi
WG Calibration/Monitoring/Site
Paris, 02/03/2007
Thank you to all
for your contributions