Alignment met hods developed f or t he val idat ion of t he t hermal and mechanical behavior of t he Two Beam Test Modules f or t he CLIC project Hélène MAINAUD DURAND, on behalf of the CLIC pre-alignment team

Agenda

• Int roduct ion • Short range st rategy of pre-alignment on module components • Preparat ion of the thermo-mechanical tests • Methods of measurements developed • Results obtained

Out line

Thermal & mechanical behavior of TBTM: alignment methods developed & misalignments observed

Int roduct ion CLIC project

Int roduct ion CLIC module

Components:

Quadrupole

PETS

Acce le rat ing St ructure (AS)

Modules = key component of CLIC • Length = 2 m • 20 000 modules

Int roduct ion CLIC module

2 Two Beam Test Modules (TBTM) under installat ion:

• Validat ion of the assembly & integrat ion of the components • Validat ion of the short range st rategy of pre-alignment • A bet t er underst anding of t hermal and mechanical behavior of a

module under dif f erent operat ing modes

Misalignment s observed

Short range st rategy of pre-alignment St rategy

Pre-alignment of several components on 1 support

2 cradles per girders “snake conf igurat ion”

cWPS & actuators coupled to each cradle

Short range st rategy of pre-alignment Process of pre-alignment

Fiducial isat ion

Pre-al ignment on girder

Inst al lat ion in t unnel

Preparat ion of thermo-mechanical test s Context of measurements

Tunnel environment reproduced by air condit ioning & vent ilat ion system:

• T© f rom 20 ©C to 40 ©C • Longitudinal air speed: 0.3 to

0.8m/s

All component s equipped with e lect ric heat ers t o reproduce the power dissipat ion est imated in t he module

Cooling syst em int egrat ed in RF component s (not in t he DB quadrupole )

1st ope rat ing scenario simulat ed: - Zero posit ion - Power-up of DB quadrupole - Unloaded condit ions (RF but no beam) - Loaded condit ions (RF + beam)

Finit e Element Analysis prepared with ANSYS to simulate displacement s (but ready during the measurement s process)

Posit ion of t he fiducials w.r.t V-shaped support axis

Posit ion of t he fiducials w.r.t mechanical axis of t he component

Measurement s using the lase r t racker AT 401

Preparat ion of thermo-mechanical tests

Preparat ion of thermo-mechanical test s Zero posit ion of the components

Methods of measurements Means of measurements

cWPS coupled to the cradle

Permanent monitoring of t he posit ion of t he girde r (mean axis of V-shaped support ), within a few µm

AT 401 measurement s

Posit ion of t he component s on the girde r

Methods of measurements Means of measurements

AT 401 measurements

• Nobody allowed in the room during the measurements

• Use of a heavy t ripod for a bet ter stabilit y • Durat ion of a stat ion < 45’ • Warm-up of AT401 4 hours before the

f irst measurements • All measurements performed back side

and f ront side, integrated over 5’’. • Fiducials located on the girder considered

as references during best -f it s (as measured by CMM)

Results : misalignments observed Misalignments of components

How to understand the data?

init ial posit ion of t he mean axis of girder

current posit ion of t he mean axis of girder

current posit ion of t he mean axis of component w.r.t mean axis of girder

Results : misalignments observed Misalignments of components

During the DBQ heat ing: vert ical displacements of ~40μm are obse rved, as no cooling system is associat ed with t he DBQ (for a T© of 35 ©C) The unloaded cycle has been pe rformed twice : t his gives a good idea of t he repeat abilit y, be t t e r t han 10 μm and confirms the precision of measurement s

Results : misalignments observed Misalignments of components

No radial displacements visible, which seems logical: a T© increase should not misalign radially the reference axis of the component as it is symmet ric. Very good repeatabilit y: this conf irms the precision of measurements

Results : misalignments observed Misalignments of components

Misalignments during the f irst phase are very small, which is logical as there is no heat ing on the MB side. The cooling system plays it s role during the unloaded and loaded phases: misalignments < 20 μm

Results : misalignments observed Misalignments of components

No radial misalignments observed as the component is symmet ric.

Summary

• Heaters added to the components, cooling system to RF components

• T©, cWPS, AT401 measurements performed

• FEM carried out

• Have a be t t e r knowledge of t he rmal expansion of t he cradle (where sensors are locat ed) w.r.t girde r

• Increase t he number of st at ions pe r side • Use simult aneously 4 AT 401 measuring the posit ion

of t he component s • To equip all t he component s with fiducials • To automat ize t he process of measurement s

One first duty cycle (machine st art -up) simulat ed

Improvement of t he methods of measurement s needed

• Very small impact of such cycle on the alignment of component s t hat are cooled down

• Good mat ching be tween simulat ions and measurement s

• At the limit of t he uncert ainty of measurement s of AT401

Would anybody have an experience in t hat ?