Metrology and pre-alignment of the components of CLIC in the PACMAN project

S. W. Kamugasa, V. Vlachakis

CLIC Workshop26-30 January 2015

CERN, Geneva, Switzerland

Particle Accelerator Component’s Metrology and Alignment to the Nanometer scale

Project

funded Innovative Doctoral Program, hosted by

Universities & Laboratories:• Cranfield University• ETH Zürich• LAPP• SYMME• University of Sannio• IFIC• TUDELFT• University of Pisa

Industrial Partners:• DMP• Eltos • Etalon A.G.• Hexagon• Metrolab• National Instruments• SigmaPhi• TNO

CLIC alignment challenge Beam size at IP ≈ 40 nm × 1 nm Achievable with beam based alignment Modules pre-alignment: 10 μm / 200 m sliding window

Current pre-alignment strategy1. Fiducialization

2. Alignment of components on common support

3. Alignment of common support in tunnel

LASE

R TR

ACKE

R

LASE

R TR

ACKE

R

20,000 modules

Proposed strategy

Integrate fiducialization and alignment on a common support at the same place and same time

• Reduce build up of systematic and random errors

• Achieve required precision & accuracy

• Requires combination of several technologies

Measure distances Estimate:

3D coordinates + uncertainties Least squares adjustment

Adapt FSI (Frequency Scanning Interferometry)

Multilateration

𝑙 𝑖𝑗

𝑣 𝑖𝑗

𝐹 𝑖

𝑅 𝑗

Y

X

Z

Target 3D position ()

Emitter 3D position ()

distance observation

residual

Developed by Oxford

Absolute distance measurement

Employs second laser to counter drift

Traceability ensured by measurement to gas cell

0.5 µm/m uncertainty (95% CL)

Simultaneous measurements (up to 100 distances)

Absolute Multiline

Abso

lute

Mul

tilin

e by

Eta

lon

AG

Wide viewing angle retroreflector for optimum geometry

Modify fibre end housing to enable absolute distances to be measured

Calibration strategy

Multilateration network

Wire measurement

Simulations

FSI adaptation

Based on Triangulation

• Determines 3D coordinates of geodetic network

• Measures angles (horizontal & vertical)

• Requires distance for scale

Micro-triangulation

• High accuracy industrial theodolites

• Short range measurements

• Few µm precision

Micro-triangulation

Hz

V

Zenith

QDaedalus

• Developed by ETH Zurich Geodesy and Geodynamics lab

• Consists of hardware & software developments

• Replaces eye piece with CCD camera non destructively

• Can reach precision of 10 µm in 3D coordinates

QDaedalus

Optical Target Recognition (OTR)

• Centre of mass

• Template least squares matching

• Circle matching

• Ellipse matching

Advantages of OTR

• Distant, fragile, hot or cold targets can be used

• Relatively cheap targets

• No need to touch targets

• Useful in hazardous environments

Detection algorithms

Micro-triangulation developments

Stretched wire algorithm

• 0.1 mm wire detection (image processing)

• Extraction of angle measurements

• 3D vector reconstruction

Other enhancements

• Hardware

• Software

Conclusion

PACMAN aims:

Tasks:

Y

X

Z

Thank you!