The Mechanical Engineering within STFC Technology is project based, projects varying in time from a few days to many years. The larger projects are usually collaborations with other research institutes e.g. CERN (the European Particle Physics Centre), and the hardware may be built anywhere in the world.

Our Engineering includes;Mechanical Engineering Design – concepts, development of ideas

Project Management – financial management, Health & Safety, use of resources

Project Engineering - planning, milestones, costings

Structural Analysis – Use of FEA, analysing designs, vibration, seismic calculations

Procurement – contractual requirements, delivery details

Assembly – Supervision, training, auditing

Particular experience in Beamline Engineering, with associated Vacuum technology and motion control.

Typical projects are International and are collaborative requiring both technical leadership and team member skills

Mechanical Engineering

STFC Technology Project areas detailed on following pages

ATLAS (A Toroidal Lhc ApparatuS)

CMS (Compact Muon Solenoid)

LHCb (Large Hadron Collider beauty)

SR (Synchrotron Radiation) Instruments

Beamline components

Magnet testing

Advanced LIGO (Laser Interferometric Gravitational wave Observatory)

MICE (Muon Ionisation Cooling Expt)

T2K

4m Superconducting Helical Undulator

ATLAS (A Toroidal Lhc ApparatuS)

Silicon Trackers (SCT)

The SCT trackers lie in the centre of the ATLAS experiment. They determine the

properties of the charged particles produced by the colliding beams.

•Demanding Mechanical Requirements:

•Stiff and extremely stable structures to accurately position the detectors and

support power, cooling, and readout services.

•These must be constructed from non-magnetic materials and be radiation

tolerant to withstand 10yrs+ of operation.

•The absolute minimum amount of material must be used since it will absorb

particles and make the data less accurate.

STFC work areas on ATLAS

– 1) SCT Wheels

– 2) End Cap Main Structure

– 3) Environmental Housing

– 4) SCT Services

– 5) SCT Tooling

– 6) Services Arm

Links to further information on ATLAS

• http://atlas.ch/index.html

• http://atlas.ch/photos/index.htmlAn early prototype cylinder

1 – SCT Wheels

A set of 9 structural disks covered with silicon detector modules and

services, there are termed „Wheels‟.

2 – SCT StructureA stable structure to support the Wheels. A carbon fibre reinforced plastic

(CFRP) sandwich structure was chosen to give a lightweight, very stable

structure.

•Positional stability better than a few 10s of m over a day required.

•Design analysed to ensure strong and stiff enough for 200kg load.

•Load tests on completed structure proved capability

•Analysis showed that deflections due to any likely vibrational input would

be very small and not affect data.

3 – SCT Environmental

Housing3 Functions:

a) Enable the tracker to be a thermally neutral sealed containment for N2

dry gas purge with grounding & shielding requirements.

b) Plastic foams, low emissivity surfaces and external heaters produce a

partially active thermal enclosure to minimising insulating volume.

c) Heat loads from the external environment and internal electrical

services were balanced internally to ensure the assembly was

thermally neutral.

4 – SCT Services

Routing of services (optical fibre, electrical, fluid cooling, gas purge)

This included defining the length of each of the services.

This routing shaped many of the other major parts (Internal patch panels,

support structure, environmental housing). This required specialised cable

trays, hardware & wrappings for thermal management / Grounding &

Shielding, and the compact multi-service patch panels.

5 – ATLAS SCT Tooling

Required to 1) Assemble the detector

2) integrate it into ATLAS

6 – Services Arm

The superconducting ATLAS end cap and barrel

toroid magnets require copious quantities of

cyrogens and other services.

These services required an 18 metre long

flexible support arm which was not commercially

available.

CMS (Compact Muon Solenoid)CMS is also a particle measuring instrument on the LHC.

The requirement here was to provide a mechanical support structure for the large mass of

7500 detector crystals, yet allow them to be extremely precisely positioned.

This was achieved with „D‟ shaped backplates which are cantilevered from the main body of

CMS by a large aluminium support ring. This ring had to be specially cast. The back plates

have hundreds of holes carefully machined in them (see picture) to allow the accurate

location of the detectors. The design allows the services to be routed back through the

backplate and support ring.

Following pictures

Backplate and Support Ring:machining and attachment

Perspective view from pit

Accurately positioning the detectors

Links to further information on CMS:

Wikipedia http://en.wikipedia.org/wiki/Compact_Muon_Solenoid

CMS Public domain http://cms.cern.ch/

CMS Outreach http://cmsinfo.cern.ch/outreach/

CMS

CMS

CMS

Accurately positioning the detectors

LHCb

Experi

ment

Photo shows CERN (European Particle Physics Research

Centre) near Geneva and the path of the large

underground accelerator

Key components are the RICH (Ring Imaging Cherenkov) detectors.

The largest of these is RICH2 which measures the velocity of charged particles.

In combination with the momentum this permits their identification.

LHCb Experiment

RICH2RICH1

RICH1Detector

STFC responsibility:Composite Exit Window& Beam Pipe Seal

STFC responsibilityVELO Seal

CF4 gas volume : ~100 m³

RICH2

FEA of RICH2

Superstructure

Distortions due to gravity

< 1mm in 10m

RICH2 in Final Position

Magnet

RICH1RICH2

E Cal

SR (Synchrotron Radiation) Instruments

• Multi Polarimeter• The Multilayer Polarimeter is a collaborative project between STFC and Diamond Light Source Ltd (DLS)

• Working Principle• This is based on the polarising properties of reflecting surfaces and transmitting thin films referred to as multilayers. The polarimeter will

be a mobile instrument and will be connected to existing beamlines in the region between 90 and 1200eV. Incident light will pass into a

UHV vessel and through the retarding multilayer to introduce phase retardation before being reflected by the analyser multilayer. The

intensity of the reflected light will be measured by a suitably positioned detector. The instrument comprises of other associated optical

elements mounted on an optical bench within a vacuum vessel and uses pinholes to define the beam axis and includes a beam filtering

system. The instrument is mounted on a Hexapod support and manipulation system.

Following pages give more details on:

Hexapod

Rotation of Multilayers

Multilayer Exchange System

Hexapod

The Hexapod, supplied by Oxford Danfysik, has 6 degrees of motorised motion and is supported and driven by 6 high

precision actuators. The linear actuators are driven by stepper motors and gearboxes with linear encoders giving positional

feedback and include end of travel limit switches. The Hexapod is controlled using EPICS software with a Delta-Tau based

motion control system. The user software is capable of orientating the instrument supported from the upper plinth around

any pre-determined co-ordinate system or point in space with positional feedback.

Rotation of Multilayers

• The retarder and analyser multilayers each require two axes of rotation and the detector also has one rotation axis. The five axes of rotation are provided using in-vacuum Huber goniometers with Renishaw encoders providing an angular resolution of as small as 0.001°. A motor driven linear stage positioned onto the analyser stage will be used with graded multilayers.

Multilayer Exchange System

• The multilayers are prone to degradation and to allow continuous operation of the polarimeter at different beamline energies, a magazine-type arrangement will be required to store the multilayers within the instrument. Individual multilayers will be mounted in their own dedicated frame holders, transfer arms and a manual rack driven transporter will be used to facilitate transfer of frame holders between the magazine and their working positions in both the retarder and analyser positions

Beamline Components

• STFC have 50 years experience of designing and manufacturing beamline components, whether for a proton synchrotron such as ISIS, or a light source e.g SRS and DIAMOND. This includes the range of magnets, accelerating cavities, monochromators, undulators/wigglers, sample positioning devices, and spatial detector systems that are required. Fundamental engineering of adjustable magnet stands, support systems and alignment tooling are vital to produce a good working beamline.

• Following pages: Example pictures of High Specification beamline components

Beamline Components 1

Beamline Components 2

Magnet Testing

STFC have extensive experience in testing different magnet types e.g. quadrupoles, undulators etc.

LIGOThe STFC team has played a major role in the Advanced LIGO (Laser

Interferometric Gravitational wave Observatory) which is being assembled in

the USA.

Development:

STFC developed the suspension concept from a physics model and

previous prototypes built in the US. We optimised the structure to achieve a

high enough stiffness and developed the mass designs to make the whole

system easy to assemble and cost effective to manufacture.

Manufacture

We have manufactured and built the Noise Prototype and the final articles

are in production.

LIGO

CAD Model Real Framework

• LIGO QUAD Assembly

MICE (Muon Ionisation Cooling Expt)

MICE is an essential step in accelerator R&D towards the realisation of a “neutrino factory”, which is the physicists‟ next

generation tool for probing matter; and could prove decisive in understanding the matter-antimatter asymmetry of the universe.

MICE is a Technology Demonstrator to prove the vital „cooling‟ mechanism

-It requires a large new dedicated facility with a precursor Muon beam line into which the novel „cooling channel‟ is assembled

This facility is being built by STFC at RAL

Major STFC Responsibilities

Project Management, together with support from international committee of collaborators

Co-ordination and integration of beamline components from abroad

Creation of the facility and all the infrastructure

Provision of key components e.g. Liquid Hydrogen system, Superconducting Pion decay channel

Running of the experiment in conjunction with ISIS, our proton accelerator

More info on following pages:

Model of cooling channel

Infrastructure

Hall layout

Photos

Links for further information

http://mice.iit.edu/

http://hepunx.rl.ac.uk/uknf/mice/?submeetings=1

MICE

• 3D Model of proposed cooling channel

4 RF Cavities/module

Tracker Module

3 Absorber Focus Coil Modules

MICE Infrastructure

• The MICE facility requires construction of major infrastructure to support the muon beamline and cooling channel e.g. ;– A Hall with power, lighting, ventilation, lifting equipment

– Massive 200 tonne magnetic shielding walls

– Provision of flat stable support for 20+ tonne beamline items

– Biological shielding

– Liquid Hydrogen handling plant

– High Voltage equipment

– Chilled water plant

– RF Amplifiers

– Magnet power supplies

• This infrastructure is near completion

Layout of MICE Hall

MICEPhotos of Early construction/integration work on the

facility and components

T2KThe T2K experiment is a second generation long-baseline neutrino-

oscillation experiment to study nature of neutrinos. Artificial neutrino

beam generated in the JHF 50GeV high-intensity proton accelerator

in JAERI (Tokai, Ibaraki) is shoot toward the 50kton water Cherenkov

detector, Super-Kamiomande, which is located about 1000m

underground in Kamioka mine(Gifu) and is 295km away from Tokai.

STFC areas of work

Target and Remote Handling Management (Info on following 2 pages)

“Near detector” (the ND280)

Baffle and the Beamline Remote Seals

T2K TARGET

components

~960mm

Ø226mm

Ø46mm

TITANIUM

GRAPHITE

T2K Remote Handling Design work

Superconducting Helical

Undulator

An exciting development programme has been carried out to produce a highly

accurate and very long 4m helical undulator.

The HeLiCal collaboration consisting of Technology, ASTeC, the German

institute DESY and the universities of Liverpool and Durham have designed and

manufactured the prototype magnet as part of research work for linear

colliders.

The following photographs show the mechanical construction of the

former/cables, and the final 4m long module.

Superconducting Helical Undulator

The ribbon is required to run in

the grooves in continuous layers

with no gap between the layers.

The picture below shows a

sectioned undulator prototype.

The former is a two-start helical spring with

a tube inserted in the bore. The picture

below shows a short length prototype.

Superconducting Helical Undulator

Machining the long former was very challenging.

Firstly a steel cylinder was gun drilled to get the accurate

centre bore. This was subsequently turned concentric to the

bore using an optical alignment technique and then the two

helixes were progressively milled using a special technique

developed in our workshop.

The essential copper tube down the centre is added

afterwards. A technique of unusually winding the

superconducting filaments as a flat ribbon has been perfected,

before finally the former is potted and machined to accurate

dimensions.

The picture shows the 1.8m former being machined, with four

supporting stays along its length

The development team with the completed 4 metre long undulator

Superconducting Helical Undulator

Update: Success!

The undulator magnets have now been powered up to 280

Amps with no quenching and left running for a period.

The helium cryogen is only being boiled off very slowly,

and a constant vacuum is being maintained. This

represents an excellent success for the project.