welcome to monalisa
DESCRIPTION
Welcome to MONALISA. A brief introduction. Who we are. Armin Reichold. David Urner. Paul Coe. Matthew Warden. Electronics support from CEG C entral E lectronics G roup. ...also collaborate closely with the LiCAS project. The context of our work. - PowerPoint PPT PresentationTRANSCRIPT
Welcome to MONALISA
A brief introduction
Who we are...
David Urner
Paul Coe
MatthewWarden
Armin Reichold
Electronics support from CEGCentral Electronics Group
...also collaborate closely with the LiCAS project
The context of our work
• HEP High Energy (particle) Physics
• Linear accelerators
• Need for alignment monitoring
• ATF-2 Advanced Test Facility
• An envisaged monitor system
• Five summer projects
High Energy "Frontier"
• To "boldly" accelerate particles in large numbers
• Nature does this already:accelerated particles strike the earth
continuously as cosmic rays– but the results are hard to monitor– there's no control over the particles
Collaborations of physicists build: • accelerators to collide beams and • detectors to monitor the results
Exploring natures spectrum• Particle on particle centre of
mass energy is the spectral variable.
• Collisions between beams excite resonances
• Particles are created• The resulting debris is
– detected– filtered and – recorded for analysis
Linear accelerators• Bunches of particles travel
kilometres in evacuated tube along a tunnel
• Bunches kept tightly focused using magnet "doublets"
• Pumped by energy in RF cavities through which they travel
Example RF accelerator cavity
Proposed ILC
• 30 km International Linear Collider (e+ e-)
• Electron against Positron collisions
• (Particle) Physics programme complements LHC – Large Hadron Collider at CERN
• Beam energy can be tuned up to 500 GeV and later up to 1 TeV
e+
Positron
The ILCs functional elements
main linacbunchcompressor
dampingring
source
pre-accelerator
collimation
final focus
IP
extraction& dump
KeV
few GeV
few GeVfew GeV
250-500 GeV
One half of a linear collider
Electrons bunches are accelerated along a 12km main linac
Focused here
Collide here300 x 6 nmspot size
To see rare particlesthey need particle collisions with tightly focused beams
What do physicists want from the international linear collider?
Large aspect ratio, few 100 nm x few nm......and they must be made to collide!
Detector
Axial view of beams at the focuselectrons
positrons
Machine performance : Luminosity
InteractionPoint
Final focusquadrupolemagnet
• One shot with each bunch!• Most electrons in a bunch do NOT produce “events”• Bunches focused to less than 10 nm in vertical
Performance depends on good alignment…
…but ground motion creates micron displacements in 100 s
Want relative motion information …
Advanced Test Facility (Japan)
ATF2 extraction line: 08 Feb 2008
QD0
QD1
Advanced Test Facility (Japan)
ATF2 Final focus region
Shintake Monitor
Final Focus Quadrupole
Stabilisation monitoring
• Between neighbouring accelerator components
• Most important is the vertical component
• Resolution target nm
• Typical range up to 10 m
Monitoring grid
Straightness monitor concept
• Displacements along 8 interferometer lines
Compact Straightness Monitor (CSM)
Distance Meter Interferometers
Simulated fringe pattern – as would be seen on a camera
2 techniques deployed together in same interferometer• Frequency Scanning Interferometry (FSI) – range• Fixed Frequency Interferometry (FFI) - changes
Interferometer operation
Intensity
Interferometer phase is calculated from fibre intensity: One photodiode per fibre
System data flow overview
Length Measurement
System
GridRecon.
Control
Temperature/Pressure
“Alignment”
Alignment model
SOFTWARE
SOFTWARE
HARDWARE + SOFTWARE
Summer projects 2008
• Data read out for our hardware– FPGA programming– USB control and readout
• Understanding the interferometer grid– Multilateration– Piezo and retroreflector calibration
• Data display and analysis– Employing LiCAS Analysis Framework
Interferometer operation
Phase = 2π (Optical Path Distance) / Wavelength
Φ = 2π D / λ = 2π D (ν / c)
D = (c/ 2π) (ΔΦ/Δnu)
R = (c/ 2π) (Δθ/Δnu)D = R (ΔΦ/Δθ)
ΔD = (c/2π ν) ΔΦ
Fixed Frequency Interferometry
Frequency Scanning Interferometry
Geometry
Measure movement of QD0s with respect to some points radially outwards through detector field yoke
Then must measure the relative motion of these end points
Exact geometry to be determined in synch with detector design
Final Vertically Focussing Quadrupole
Solenoid return yoke
Distance Meter
Straightness Monitor
Detail for single QDzero
Geometry
Measure movement of QD0s with respect to some points radially outwards through detector field yoke
Then must measure the relative motion of these end points
Exact geometry to be determined in synch with detector design
Final Vertically Focussing Quadrupole
Solenoid return yoke
Straightness monitor concept