clic and hl-lhc alignment requirements
DESCRIPTION
CLIC and HL-LHC alignment requirements. SUMMARY CLIC project: Introduction to the CLIC project Alignment requirements HL-LHC project: Introduction to the HL-LHC project Alignment requirements Common alignment requirements of both projects. CLIC: introduction to the project. - PowerPoint PPT PresentationTRANSCRIPT
H. MAINAUD DURAND
CLIC and HL-LHC alignment requirements
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SUMMARY
CLIC project:o Introduction to the CLIC projecto Alignment requirements
HL-LHC project:o Introduction to the HL-LHC projecto Alignment requirements
Common alignment requirements of both projects
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CLIC: introduction to the project
H. Mainaud Durand
Study for an e- e+ collider with a centre of mass energy of 3 TeV
Sub-µm beam size, down to a few nm at the IP A number of challenges to be mastered, among which:
o Very tight tolerances of alignment of components, to about 10 µm over a distance of 200mo Active stabilization of the quadrupoles in the nanometre range required
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CLIC: introduction to the project
H. Mainaud Durand
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CLIC: introduction to the project
H. Mainaud Durand
Based on a two beam acceleration concept Each linac consists of more than 10 000 modules (with a 2m length)
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CLIC: introduction to the project
H. Mainaud Durand
Different types of components: Quadrupoles :
o MB quadrupoles: ~ 4000 o DB quadrupoles: ~ 42 000
BPM: one per each quadrupole Accelerating structures: ~ 142 800 PETS components: ~ 71 000
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CLIC: alignment requirements
H. Mainaud Durand
Starting point = challenge concerning the pre-alignment of the CLIC components.
Requirements:
The zero of each component will be included in a cylinder with a radius of a few micrometers:
10 µm (BDS components) 14 µm (RF structures & MB quad BPM) 17 µm (MB quad) 20 µm (DB quad)
Active alignment consists of two steps: Determination of the position by alignment sensors Re-ajustment by actuators
Within +/- 0.1 mm (1s)
Active pre-alignment Beam based alignment Beam based feedbacksWithin a few µm
Mechanical pre-alignment
PRE-ALIGNMENT (beam off)
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SUMMARY
CLIC project:o Introduction to the CLIC projecto Alignment requirements
HL-LHC project:o Introduction to the HL-LHC projecto Alignment requirements
Common alignment requirements of both projects
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HL-LHC: introduction to the project
H. Mainaud Durand
Objective: to extend the discovery potential of the LHC, by increasing its luminosity by a factor 10 beyond its design value
Key innovative technologies:- cutting-edge 13T superconducting
magnets- Very compact and ultra precise
superconductive cavities for beam rotation (crab cavities)
- 300 m long high power superconducting links with zero energy dissipation
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HL-LHC: introduction to the project
H. Mainaud Durand
HL-LHC: introduction to the project
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HL-LHC: Introduction to the project
H. Mainaud Durand
ATLASCMS
P. FessiaJP Corso and EN-MEF int. team
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HL-LHC: introduction to the project
H. Mainaud Durand
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HL-LHC: introduction to the project
H. Mainaud Durand
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HL-LHC: alignment requirements
H. Mainaud Durand
Within +/- 0.1 mm ? (1σ) Initial alignment (absolute position)
Smoothing
Fiducialisation
Within +/- 0.1 mm (1σ)
Monitoring of the relative position
Remote adjustment if needed
Within a few µm
Beam
Monitoring of the relative position
Remote adjustment if needed
Within +/- 0.1 mm (1σ)
Within +/- 0.1 mm ? (1σ)
Monitoring of the position of the cold mass w.r.t. external fiducials
Triplet
Other components of the LSS
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SUMMARY
CLIC project:o Introduction to the CLIC projecto Alignment requirements
HL-LHC project:o Introduction to the HL-LHC projecto Alignment requirements
Common alignment requirements of both projects
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Common requirements between both projects
H. Mainaud Durand
The determination of the position of the component can be divided (as an approximation) into two steps:
Determination of the “zero” of the component • In the referential frame of its mechanical support• In the referential frame of the sensor
Determination of the position of the referential frame of the sensor coupled to the component w.r.t a stretched considered as a straight reference
Step 1
Step 2
Step 1
Magnet
Mechanical support
Sensor referential frame
Straight reference
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BDS: strategyCommon requirements between both projects
H. Mainaud Durand
Straight reference
Sensor
Straight reference:
- Length > 200 m- Stable, along time, according to environment
conditions- Straight at a few micrometers
Sensor:
- Biaxial sensor, providing radial and vertical offsets w.r.t alignment reference
- Interchangeable at the micrometer level
- Repeatability of measurements < 1 μm
- Accuracy < 5 μm- Limited drift- Radiation hard, possibility of
remote electronics- Frequency of acquisition: 20 Hz.
n sensors, with n > 100
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BDS: strategyConclusion
H. Mainaud Durand
Alignment requirements between both projects are quite different:
• For HL-LHC: relative monitoring at the micrometer level, in a very severe environment
• For CLIC: absolute alignment at the micrometer level
In both cases, we will need:
• A straight alignment reference, stable along time and environment, over a length above 200 m
• n sensors (n between 20 and 100), plugged on the components to be aligned, providing radial and vertical offset measurements w.r.t the alignment reference at a micrometric accuracy.
Can the laser beam be such a straight reference?• what about the stability of the beam, the stability of the laser source• Is vacuum needed on such distances? Which vacuum? Are there other solutions?• What is the impact of temperature, humidity and other parameters on the
straightness of the laser beam?• How to be sure of the straightness of the beam?
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BDS: strategyConclusion
H. Mainaud Durand
Concerning the sensors:
• Which type of sensor can fulfil such requirements?• What is the impact of the diameter of the laser beam w.r.t. accuracy of the sensor?• How to attach the sensor to the component, and measure w.r.t. a laser beam under
vacuum?• How to transfer the position of the laser beam outside the vacuum pipe without any
constraints?• Are there rad hard sensors?• Which kind of algorithm for image processing should be used?
Then, once we have found a solution: how to validate the global solution?
These are a lot of questions! We hope to find a great number of answers during your presentations, and during the brainstorming.
SPARES SLIDES
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BDS: strategy concerning the determination of positionSolution proposed
Installation and determination of the surface geodetic networkTransfer of reference into
tunnel
Absolute alignment of the elements
Relative alignment of the elements
Active prealignment
Control and maintenance of the alignment
H. Mainaud Durand
Installation and determination of the tunnel geodetic network
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Solution proposed
Transfer of reference into tunnel
Installation and determination of the tunnel geodetic network
Combination of 3D triangulation and trilateration coupled with measurements on vertical plumb wires
Methods validated on an LHC pit in 2010 (depth of 65 m): precision of 0.1 mm and accuracy of 0.5 mm
Hypothesis considered for CLIC: absolute position at the bottom of each pit: ± 2 mm (depth > 100 m)
Distance < 2.5 km
BDS: strategy concerning the determination of position
H. Mainaud Durand
Installation and determination of the surface geodetic network
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BDS: strategy
Solution proposed Absolute alignment of the elements
Relative alignment of the elements
Metrological Reference Network
Installed w.r.t the tunnel geodetic network
Overlapping stretched wires propagating the precision over long distances
Simulations in 2009: o Precision at the bottom of the shaft of ± 2 mmo Calibration of metrological plates: ± 5 μmo Distance between pits: 3.5 kmo Wires: 400m long Std deviation of 3.6 μm over 200m
of sliding window
Propagation network simulations
BDS: strategy concerning the determination of position
H. Mainaud Durand
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BDS: strategy
Solution proposed Absolute alignment of the elements
Relative alignment of the elements
TT1 facility
Precision on a 140 m wire: better than 2 microns over 33 days Standard error in the determination: 11 microns in vertical, 17
microns in radial. Can be improved!
BDS: strategy concerning the determination of position
H. Mainaud Durand