Download CTA-LST Large Size Telescope

CTA-LST Large Size Telescope
M. Teshima for the CTA Consortium
Institute for Cosmic Ray Research, University of Tokyo
Max-Planck-Institute for Physics
Large Size Telescope (LST) in CTA
Two stations for all sky observatory
North: Canaries / Mexico
South: Namibia / Chile /
Argentina
LST 23m
LST 23m
MST 10-12m
SST 4-6m
MST 10-12m
SST 4-6m
Science case of LST
High redshift AGNs (z<3) GRBs (z<10)
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Binaries and transients
LST is optimized in the energy range between 20 - 200 GeV
Low energy threshold
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Pulsars
Trigger threshold: 15-20 GeV
Analysis threshold: 20-30 GeV
key physics cases:
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High-redshift AGNs and GRBs
Binaries, Pulsars and other type of transients at low energy
Specifications/Requirements of LST
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Diameter: 23m
Dish area: 400 m2
F/D = 1.2, F=28m
Dish profile: Parabolic
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FOV = 4.5 degrees, Pixel size = 0.1
degrees (~2500ch camera)
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Fast rotation: <180 deg/20 sec
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Dish profile: parabolic  isochronicity:
<0.6 ns RMS
Camera sagging: < 1-2 pixels
Camera oscillation in wind gust: <8mm
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 Active oscillation damping by LAPP IN2P3
Designed by MPI Munich
LST 23m size mirror reflector
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198 Hex-shape segmented
mirrors of 1.5m size
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Total area 〜400m2
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Central hole for the calibration
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Permanent AMC (Active Mirror
Control)
1.5 m Hex
Mirror prototype
by CTA-Japan
Reflectivity (%)
SiO2, HfO2 multi-coating
Wavelength (nm)
Optical axis and permanent AMC
Stars
SKY
LED
LED
OA-Lazer
PMT CAMERA
MIR-Lazers
MIR-Lazers
LED
Target
LED
IMAGE with HR CCD Camera
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Define optical axis with the IR Laser beams
High precision inclinometer (a few arcsec)  zenith angle
HR CCD camera at the center of dish to monitor the optical axis and star field
 pointing direction in sky
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(Camera LED position) – (Optical axis Laser position)  camera sag
(Mirror Laser positions) – (Optical axis Laser position)  misalignments of
mirror directions
Demonstration of Active Oscillation Damping System
for the LST Arch by LAPP IN2P3
Gamma/Hadron Separation below 100GeV
gamma
Hadron
50GeV gamma ray images with LSTs
Scaled width (below 50GeV)
Height of Shower Maximum
Optimization of Telescope geometry
Ø 1° source
Camera, clusters and Cooling
Sealed Camera
(MAGIC-II camera)
Size:
Weight:
# of Ch:
Heat:
Water cooling System
2.5 m
2 tons
~ 2500 ch
~ 5000W
Cluster Prototype by CTA-Japan
(R.Orito: #1091)
7PMTs
CW HV system
Pre-Amplifier
DRS-4 readout system (4μsec)
G-bit ethernet
Differential Sensitivity of 4 x LSTs
Below 200GeV LSTs will have a good sensitivity
Configuration E
LST x 4, MST x 23, SST 32
CTA Monte Carlo:
Expected Light curve for GRB at z=4.3
CTA performance study by S.Inoue, Y.Inoue, T.Yamamoto, et
al
Summary
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CTA-LST will provide a fairly good sensitivity between 20GeV and
200GeV
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CTA Science will be expanded to the new domain
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CTA-LST baseline design
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High redshift AGNs (z<3), GRBs(z<10), Pulsars, Galactic Transients
Diameter 23m, Focal length 28m, F/D = 1.2
FOV 4.5 degrees, Pixel size 0.1 degrees
Many new proven technologies will be implemented
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Space frame structure with CFRP
Total weight ~ 50 tons  180 degrees/20sec
Permanent active mirror control
Permanent camera oscillation damping system
Sealed camera with water cooling system
1GHz sampling DRS4 system with 4μsec deep memory
Optical axis and permanent AMC
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Define optical axis with the IR Laser beams
High precision inclinometer (a few arcsec)  zenith angle
HR CCD camera at the center of dish to monitor the optical axis and star field
 pointing direction in sky


(Camera LED position) – (Optical axis Laser position)  camera sag
(Mirror Laser positions) – (Optical axis Laser position)  misalignments of
mirror directions