1. SPS New Wire Scanner Mechanics Review
Ray Veness
BE/BI

2. Project timeline and funding Motivation for this meeting
Contents
Introduction
Wire scanners
Requirement and concept for the new wire scanner
Project timeline and funding
Motivation for this meeting
What BI would like from this meeting

4. Wire scanner design review; B.Dehning
Limitations
Reproducibility much larger as required by specification
Beam size min LHC 130, PSB 2000 um
Flexible design of wire fork
Deformation of fork are not measured
Angular position measurement outside of vacuum system
Lever arm play is not measured
Speed regulation circuit
Analog feedback loop difficult to optimize
Secondary particle acquisition system
Requires accurate adjustment of working range
Saturation effect of PM
Dynamic of working range small < 200
Tail measurement limited by noise
High intensity beams cause an increase of background signal
Dynamic of working range reduced
Aging of bellows
Motor
&
Position
sensor
Wire scanner design review; B.Dehning

5. Methodology - Conceptual Design
Vacuum chamber
Optic Fiber
Motor Stator
Optic Disc in vacuum
Resolver
Shaft
Bearings
Fork
Rotor in vacuum
This figure shows the adopted conceptual design for the new wire scanner instrument
This conceptual design has been decided before the beginning of this thesis work
The design provides 2 main advantage respect to the state of the art
(1) no mechanical transmission between the motor and the shaft -> improve accuracy
(2) the position measurement device is located directly in the shaft (in vacuum)
(3) no bellows are required to transmit the moved -> reliability is improved and maintenance work is simplified
Beam
Vacuum pipe
Wire
Slide Courtesy of J.Herranz Alvarez

6. From Schematic to Design
Vacuum chamber
Optic Fiber
Motor Stator
Optic Disc in vacuum
Magnetic lock
Bearings
Resolver
Shaft
Rotor in vacuum
RF screen
Fork
Wire

7. Wire scanner design review; B.Dehning
The Project
Project timeline
Dec 2012: Production of a prototype for SPS installation launched with MME
April 2013: External design review validates design
May 2014: Installation of the prototype tank in SPS sector 517
Jan 2015: Installation of the prototype instrument in the tank
EYETS 2016: Installation of a PS Booster prototype
LS2: Installation of 18 instruments + spares in PS, PSB, SPS
LS2-LS3: Installation of 4 or 8 instruments + spares in the LHC
Funding
Fully funded by LIU for the injectors and HL-LHC for the LHC
Wire scanner design review; B.Dehning

8. Motivations for the Meeting
Smaller beam sizes and higher intensities will make this new design specification essential for transverse profile meaurement post-LS2, so it is a key instrument for the LIU project
Existing instruments are 30+ years old and suffer from obsolescence and reliability issues
Other projects and labs are already interested in this design
We have a prototype that has been designed, built, installed in the SPS and has been operated in the lab, however…
Manufacture cost was high, acceptable for a prototype but not for a series of instruments
We need to address this both in design and production engineering
Manufacture time was long and relied heavily on CERN-specific skills, (i.e. EB welding) at a time when CERN workshops were loaded i.e. during LS1)
Some vacuum issues were found late during acceptance testing
We need to make all the qualification tests needed and agree early on materials, treatments (and bakeout for the LHC)
The SPS prototype design we have will not fit in the PS Booster
There are clear benefits from having one design, with a few different components across the whole accelerator complex

9. What BI would like from this meeting
A list of all the things that we think we can improve from the prototype:
Design, standardisation, materials, manufacturing technology, ease of manufacture, alignment
… and cost!
Discussion on the best way forward:
Communication between BI, MME and VSC
In house manufacture vs. sub-contracting
Is this a large series?