1. Welcome to MONALISA A brief introduction

2. Who we are... David Urner Paul Coe Matthew Warden Armin Reichold Electronics support from CEG Central Electronics Group...also collaborate closely with the LiCAS project

3. 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

4. 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

5. 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

6. 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

7. Example RF accelerator cavity

8. 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

9. The ILCs functional elements One half of a linear collider Electrons bunches are accelerated along a 12km main linac Focused here Collide here 300 x 6 nm spot size

10. To see rare particles they 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 focus electrons positrons

11. Machine performance : Luminosity Interaction Point Final focus quadrupole magnet 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 …

12. Advanced Test Facility (Japan)

13. ATF2 extraction line: 08 Feb 2008 QD0 QD1

14. Advanced Test Facility (Japan) ATF2 Final focus region Shintake Monitor Final Focus Quadrupole

15. Stabilisation monitoring Between neighbouring accelerator components Most important is the vertical component Resolution target nm Typical range up to 10 m

16. Monitoring grid Straightness monitor concept Displacements along 8 interferometer lines Compact Straightness Monitor (CSM)

17. 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

18. Interferometer operation Intensity Interferometer phase is calculated from fibre intensity: One photodiode per fibre

19. System data flow overview Length Measurement System Grid Recon. Control Temperature/Pressure “Alignment” Alignment model SOFTWARE HARDWARE + SOFTWARE

20. 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

23. 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

24. 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

25. 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