SST-GATE: An innovative Telescope for the Very High Energy ... · New generation of ground-based...
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1 SST-GATE: An innovative Telescope for the Very High Energy Astronomy SST-GATE: a prototype for CTA consortium Prototype of CTA-SST built at the Observatory of Paris in Meudon Project lead from mechanical and electronics design to building and test phases SST-GATE telescope as a Schwarzschild-Couder (SC) optical design: - dual mirror optical formula never built before - increase the FoV and minimise aberrations (no coma, no spherical aberration) - telescope size, weight and camera cost decrease Objective of the SST-GATE in CTA preparatory phase: 2010 – 2014 - prove the feasibility of such design at low cost (<250 k€) - prove the optical performance Challenge of building a SC Telescope for CTA Constraints of building a telescope in an array: - each telescope is ordered independently: SST-GATE has its own control system - the telescope must be compliant with others LST, MST telescopes - the telescope must comply with the power supply provided (10 kW max) - maintainability made with less than 6pers.h/week and no more 3 nights/year loss - the telescope life: 30 years without any protection - reliability of operation: 97 % of observational hours - each part of the telescope must be subcontracted Status of the project Project is well going as CTA schedule: - mechanical design is almost frozen, mechanical studies are made by FEM - last simulation and optimization are on-going as well as electronics and software - risk analysis, alignment process, error budget and MAIT process are studied in parallel Current status: - foundations already made - power supply and Ethernet will be provided by the end of 2012 - AAS will be built in spring 2013, mirror provided in summer 2013 - mechanical and optical tests will be started by the end of 2013 Conclusions and Perspectives of the SST-GATE project CTA is a challenging project in both technical and scientific aspects SST-GATE will prove the mechanical feasibility and the optical performances of a Schwarzschild-Couder design, never built before. Camera - for prototyping: CCD camera - for science: CHEC camera from Leicester Alt-Azimuthal Structure (AAS) Supporting the optical system Ability to point any direction in the sky and to track any source > 90° / min Slew speed < 5 arcsec Source localisation < 5 arcmin Tracking precision < 7 arcsec Pointing precision Environmental constraints for the telescope 0 to 100 5 to 95 5 to 95 5 to 95 Humidity range (%) > 100 65 to 100 50 to 65 0 to 50 Wind speed range (km/h) < - 20 or > + 50 - 20 to + 50 - 15 to + 45 - 10 to + 40 Temperature range (°C) Survival Emergency Critical Observing Conditions - Critical conditions: observation with degraded performance velocities and accelerations reduced down to 70% of max - Emergency conditions: return to parking position velocities and accelerations reduced down to 10% of max - Survival conditions: telescope parked and no move allowed A Schwarzschild-Couder optical system 2 mirrors M1 and M2 with the focal plane in between mirrors linked by the MTS (Mast and Truss Structure) which is 3 tubes of Φ 100 mm. Kneecaps between MTS and the M2 dish and pivot for the M1 dish Optical specifications: - low level layer: Ethernet - software layer: Ethernet-based communications with OPC UA and Object-Oriented Programming (LabVIEW, Java or C++) Shelter will be provided for Meudon considering: - the climatic conditions in Paris - our wish to decrease maintainability cost - working under protection for the building phase Trade-off realized for: - Building material: steel chosen instead of aluminium for its low price, rigidity, easiness of manufacturing and mounting - Safety system for the azimuthal axis in addition to the passive mechanism to decrease the telescope and human hazard if an undesired movement occurs - Use of 1 or 2 motor in AAS: 1 motor chosen in order to simplify the elevation and azimuthal control systems - Size of the fork: short fork preferred as it induces lower axial stresses as studied by FEM analysis Choice of a high cylindrical tower with a small closed fork mount for low cost, simplification of welding operations and low stresses Mirrors manufacturing - Mirror M1: Φ 4 m – Aspherical radius of curvature: 9.7 m tessellated mirror: 2 rings of 12 panels each - Mirror M2: Φ 2 m – Aspherical radius of curvature: 2.1 m monolithic mirror composed of 9 assembled panels Under procurement from CEA IRFU: 2.283 m Focal length 0.578 f/# 9° FoV 75 % on axis Throughput 0.1° @80% PSF 0.025°/mm Plate scale 6x6 mm² Pixel size 1 m Radius of curvature disc Φ 362 mm Detecting surface 1.2 m 0.9 m After CTA phase A, SST-GATE will be used as: - a test bed for CTA cameras - for scientific experiences in Meudon, university practical works and public visits Cherenkov Telescope Array CTA consortium New generation of ground-based Imaging Air Cherenkov Telescope 2 arrays in Northern and Southern hemisphere with 3 kinds of telescopes: - Large Size Telescope LST: primary mirror Φ 24 m – detection of lowest energy - Middle Size Telescope MST: primary mirror Φ 12 m – detection of TeV energy range - Small Size Telescope SST: primary mirror Φ 4 to 6 m – detection of up to 100 TeV Scientific objectives: explore the very high energy events by the discovery of thousands sources as supernovae remnants, pulsar wind nebulae, binary systems… Scientific questions to answer: - the origin of cosmic rays and their role in the universe - the nature of particle acceleration in systems containing black holes - the ultimate nature of matter and physics beyond the Standard Model - camera fastening to MTS result from trade-off already made - innovative solution to remove the camera by rotation avoiding human, mirrors and camera hazards and allowing a low height to work on the camera Philippe Laporte, Jean-Laurent Dournaux, Hélène Sol, Catherine Boisson, Delphine Dumas, Gilles Fasola, Fatima de-Frondat, Olivier Hervet, David Horville, Jean-Michel Huet, Isabelle Jégouzo, Andreas Zech – Observatoire de Paris à Meudon France Simon Blake, Paula Chadwik, Jürgen Schmoll – Durham University United Kingdom ∙ Tim Greenshaw University of Liverpool United Kingdom ∙ Jim Hinton, Richard White – University of Leicester United Kingdom Telescope Control and Alignment (TCA) controlling the telescope adequately to perform scientific operations use of a main PLC, a safety PLC, a local control panel and remote workstations for human interface Mirror M2 Mirror M1 Focal surface 3.56 m 0.51 m
Transcript of SST-GATE: An innovative Telescope for the Very High Energy ... · New generation of ground-based...
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SST-GATE: An innovative Telescope for the Very High Energy Astronomy
SST-GATE: a prototype for CTA consortium
Prototype of CTA-SST built at the Observatory of Paris in Meudon
Project lead from mechanical and electronics design to building and test phases
SST-GATE telescope as a Schwarzschild-Couder (SC) optical design:
- dual mirror optical formula never built before
- increase the FoV and minimise aberrations (no coma, no spherical aberration)
- telescope size, weight and camera cost decrease
Objective of the SST-GATE in CTA preparatory phase: 2010 – 2014
- prove the feasibility of such design at low cost (<250 k€)
- prove the optical performance
Challenge of building a SC Telescope for CTA
Constraints of building a telescope in an array:
- each telescope is ordered independently: SST-GATE has its own control system
- the telescope must be compliant with others LST, MST telescopes
- the telescope must comply with the power supply provided (10 kW max)
- maintainability made with less than 6pers.h/week and no more 3 nights/year loss
- the telescope life: 30 years without any protection
- reliability of operation: 97 % of observational hours
- each part of the telescope must be subcontracted
Status of the projectProject is well going as CTA schedule: - mechanical design is almost frozen, mechanical studies are made by FEM- last simulation and optimization are on-going as well as electronics and software
- risk analysis, alignment process, error budget and MAIT process are studied in parallel
Current status: - foundations already made- power supply and Ethernet will be provided by the end of 2012- AAS will be built in spring 2013, mirror provided in summer 2013- mechanical and optical tests will be started by the end of 2013
Conclusions and Perspectives of the SST-GATE project
CTA is a challenging project in both technical and scientific aspects
SST-GATE will prove the mechanical feasibility and the optical performances of a Schwarzschild-Couder design, never built before.
Camera
- for prototyping: CCD camera
- for science: CHEC camera from Leicester
Alt-Azimuthal Structure (AAS)
� Supporting the optical system
� Ability to point any direction in the sky and to track any source
> 90° / minSlew speed
< 5 arcsecSource localisation
< 5 arcminTracking precision
< 7 arcsecPointing precision
Environmental constraints for the telescope
0 to 1005 to 955 to 955 to 95Humidity range (%)
> 10065 to 10050 to 650 to 50 Wind speed range (km/h)
< - 20 or > + 50- 20 to + 50- 15 to + 45- 10 to + 40Temperature range (°C)
SurvivalEmergencyCriticalObservingConditions
- Critical conditions: observation with degraded performance
velocities and accelerations reduced down to 70% of max
- Emergency conditions: return to parking position
velocities and accelerations reduced down to 10% of max
- Survival conditions: telescope parked and no move allowed
A Schwarzschild-Couder optical system
� 2 mirrors M1 and M2 with the focal plane in between
� mirrors linked by the MTS (Mast and Truss Structure) which is 3 tubes of Φ 100 mm. Kneecaps between MTS and the M2 dish and pivot for the M1 dish
� Optical specifications:
- low level layer: Ethernet - software layer: Ethernet-based communications with OPC UA and Object-Oriented Programming (LabVIEW, Java or C++)
Shelter will be provided for Meudon considering:
- the climatic conditions in Paris
- our wish to decrease maintainability cost
- working under protection for the building phase
Trade-off realized for:
- Building material: steel chosen instead of aluminium for its low price, rigidity, easiness of manufacturing and mounting
- Safety system for the azimuthal axis in addition to the passive mechanism to decrease the telescope and human hazard if an undesired movement occurs
- Use of 1 or 2 motor in AAS: 1 motor chosen in order to simplify the elevation and azimuthal control systems
- Size of the fork: short fork preferred as it induces lower axial stresses as studied by FEM analysis
Choice of a high cylindrical tower with a small closed fork mount for low cost, simplification of welding operations and low stresses
Mirrors manufacturing - Mirror M1: Φ 4 m – Aspherical radius of curvature: 9.7 m
tessellated mirror: 2 rings of 12 panels each- Mirror M2: Φ 2 m – Aspherical radius of curvature: 2.1 m
monolithic mirror composed of 9 assembled panels Under procurement from CEA IRFU:
2.283 mFocal length
0.578f/#
9°FoV
75 % on axisThroughput
0.1° @80%PSF
0.025°/mmPlate scale
6x6 mm²Pixel size
1 mRadius of curvature
discΦ 362 mmDetecting surface
1.2 m0.9 m
After CTA phase A, SST-GATE will be used as:
- a test bed for CTA cameras
- for scientific experiences in Meudon, university practical works and public visits
Cherenkov Telescope Array CTA consortium
New generation of ground-based Imaging Air Cherenkov Telescope
2 arrays in Northern and Southern hemisphere with 3 kinds of telescopes:
- Large Size Telescope LST: primary mirror Φ 24 m – detection of lowest energy
- Middle Size Telescope MST: primary mirror Φ 12 m – detection of TeV energy range
- Small Size Telescope SST: primary mirror Φ 4 to 6 m – detection of up to 100 TeV
Scientific objectives: explore the very high energy events by the discovery of thousands sources as supernovae remnants, pulsar wind nebulae, binary systems…
Scientific questions to answer:
- the origin of cosmic rays and their role in the universe
- the nature of particle acceleration in systems containing black holes
- the ultimate nature of matter and physics beyond the Standard Model
- camera fastening to MTS result from trade-off already made
- innovative solution to remove the camera by rotation avoiding human, mirrors and camera hazards and allowing a low height to work on the camera
Philippe Laporte, Jean-Laurent Dournaux, Hélène Sol, Catherine Boisson, Delphine Dumas, Gilles Fasola, Fatima de-Frondat, Olivier Hervet, David Horville, Jean-Michel Huet, Isabelle Jégouzo, Andreas Zech – Observatoire de Paris à Meudon France Simon Blake, Paula Chadwik, Jürgen Schmoll – Durham University United Kingdom ∙ Tim Greenshaw University of Liverpool United Kingdom ∙ Jim Hinton, Richard White – University of Leicester United Kingdom
Telescope Control and Alignment (TCA)
� controlling the telescope adequately to perform scientific operations� use of a main PLC, a safety PLC, a local control panel and remote workstations for human interface
Mirror M2
Mirror M1
Focal surface
3.56 m
0.51 m
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