clic ff where we stand, where are we going?
DESCRIPTION
CLIC FF where we stand, where are we going?. A.Jeremie. Short summary. Achieved performance Current work Future plans. Schedule with strong incentive from CDR in 2010! FF part of both the MDI WG and the Stabilisation WG => liaison A.Jeremie. Comments: Several PhDs: - PowerPoint PPT PresentationTRANSCRIPT
CLIC FF where we stand,where are we going?
A.Jeremie
Short summary• Achieved performance• Current work• Future plans
Tolerances Final Focusing Quadrupoles
Vertical 0.1 nm > 4 Hz
Horizontal 5 nm > 4 Hz
Comments:•Several PhDs: –S.Redaelli (CERN) 2003–B.Bolzon (LAPP) 2007–M.Warden (Oxford) ~2010–R. LeBreton (SYMME) ~2011•Each time a new team starts this study, there is a non negligible “learning period”.
Schedule with strong incentive from CDR in 2010!FF part of both the MDI WG and the Stabilisation WG => liaison A.Jeremie
Achieved performance
CERN TMC active table for isolation
The two first resonances entirely rejected
Achieved integrated rms of 0.13nm at 5Hz
LAPP active system for resonance rejection
L.Brunetti et al (EPAC/Genova 2008)
Current workReplace big stabilisation table by a compact passive+active stabilisation system
Instrumentation study (sensors and actuators)• Seismometers (geophones)
Velocity Acceleration
• Accelerometers (seismic - piezo)
Streckeisen STS2
GuralpCMG 3T
Guralp CMG 40T
EentecSP500
PCB393B31
electrochemical
Endevco86
PCB393B12
B&K450B3
• Seismometers (geophones)
Velocity Acceleration
• Accelerometers (seismic - piezo)
Streckeisen STS2
GuralpCMG 3T
Guralp CMG 40T
EentecSP500
PCB393B31
electrochemical
Endevco86
PCB393B12
B&K450B3
Active system
Passive system
Current work
Ex : force (actuator) applied to a point
Feedback development
Cantilever beam simulationwith and without control
Uniform RandomNumber
To File 2
control .mat
To File 1
BO.mat
To File
BF.mat
Sum
State -Space 1
x' = Ax+Bu y = Cx+Du
State -Space
x' = Ax+Bu y = Cx+Du
Selector 2
U Y
Selector 1
U Y
Selector
UY
Quantizer 1 Quantizer
Open loop
Gain 2
-K-
Gain 1
K*u
Gain
K*u
Control
Closed loop
Simulations
Different strategies studied:•A knowledge only at strategic points
•A local model for the disturbances amplified by eigenfrequencies.
•A complete modelEvgeny Solodko
FF magnet design
FF stabilisation
• Performance issue: if not sufficent => show stopper
• Cost issue: only one pair (QD0 and QF1) on each side of the detector. In principle, not a big cost issue. However, very stringent specs, so costly high performance components.
FF needs towards feasibility demonstration
• Remember: subnanometer stabilisation at 5Hz already demonstrated in laboratory on a cantilever prototype. Is this sufficient to convince that we can do it?
• What is missing?
What is needed?
• Reliable sensors (small, rad hard, magnetic field hard, low frequency range, nm range). So far only coil sensors used and the molecular sensors don’t seem to be stable in time. Geophones and accelerometers: do we need displacement sensors? Where should they go?
• Reliable actuators: piezo stacks (Cedrat, PI) OK. Still to confirm weight range and displacement range.
• Feedback algorithm: cantilever compensation demonstrated for one sensors/one actuator. Is this enough? Study new algorithms with mutlisensors/multiactuators, complete structure model, compare co localised and distributed.
• Demonstration done on big TMC table. Replace the isolation function by a more compact device. Commercial? Are there weight and configuration issues (how can a small device hold a cantilever?).
• Understand what influences tolerances (coherence, supports…)
FF needs towards feasibility demonstration
• Can we build a PM FF? How stable can a long structure made out of short pieces be? Simulations.
• How much space is there for the FF? What shape with the spent beam? Aperture? Is FF different for 500GeV?
• How can it be supported inside the detector? Are we considering a Push-Pull scenario? A study to be done – Cantilever on detector– Cantilever from tunnel– Multifeet from detector– Cantilever from ground (height!!!)– Suspended from detector– Suspended from ceiling (correlation possible for both QD0?)– Common girder through detector…
• Need an in depth study with detector conception.• A detector can never be built with the right vibration tolerances!
M.Oriunno, SLACLCWS08, Chicago November ‘08
Integration for the Push-Pull
17 m
8.6 m
A.Seryi, November 17, 2008 BDS: 11
• Study prompted by the CLIC FD stability challenge (< 0.2nm) • Double the L* and place FD on a stable floor• Initial study show that L*=8m optics is possible (CLIC08 workshop)
» Some (maybe tolerable) impact on luminosity is still unavoidable
CLIC08
Longer L*
FF needs towards feasibility demonstration
• Can we build a PM FF? How stable can a long structure made out of short pieces be? Simulations.
• How much space is there for the FF? What shape with the spent beam? Aperture?
• How can it be supported inside the detector? Are we considering a Push-Pull scenario? A study to be done – Cantilever on detector– Cantilever from tunnel– Multifeet from detector– Cantilever from ground (height!!!)– Suspended from detector– Suspended from ceiling (correlation possible for both QD0?)– Common girder through detector
• Need an in depth study with detector conception• A detector can never be built with the right vibration tolerances!• Would the FF magnet be simpler for L*=8m (without the spent
beam in the way)?
What if we only keep the L*=8m for th
e first stabilisation studies
(at least until th
e CDR is over)?
prototypes
• Short FF magnet 2010: what can be learned for stabilisation purposes? Pinpoint some sources. Measure with different cooling flows: air, laminate, turbulent.
• Use the cantilever prototype for further studies?
Accelerator environment?
• Module 104 studies in CLEX: 2010• Electron beam studies (CESR TA and PSI): 2009-
2010• Can we learn from the new FDs in ATF2: 2013?
– Active stabilisation needed? Learn from the study.– Vibration sources different– Optics with longer magnet similar?– Is ATF2 going to use both technologies?
Summary of actions needed• Reliable sensors• Reliable actuators• Feedback algorithm• Replace the isolation function by a more compact device.• Can we build a PM FF? How stable can a long structure made out
of short pieces be? Simulations.• How much space is there for the FF? What shape with the spent
beam? • How can FF be supported?• Detector conception.• Prototypes• Behaviour of magnet (simulations)• Accelerator environment?
Items covered by MB stabilisation studiesThose needing extra work
How does this fit with the CDR?MDI-FF review proposed for December 2009-January 2010