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Mechanical Engineering
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
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
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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
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http://atlas.ch/index.html
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http://atlas.ch/photos/index.html
An 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 Structure
A 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 Functions:
3 – SCT Environmental
Housing
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
LHCb Experiment
RICH1
RICH2
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.
RICH1Detector
STFC responsibility
VELO Seal
STFC responsibility:
Composite Exit Window
& Beam Pipe Seal
RICH2
CF4 gas volume :
~100 m³
FEA of RICH2
Superstructure
Distortions due to gravity
< 1mm in 10m
RICH2 in Final Position
Magnet
RICH2
E Cal
RICH1
SR (Synchrotron Radiation) Instruments
• Multi Polarimeter
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The Multilayer Polarimeter is a collaborative project between STFC and Diamond Light Source Ltd (DLS)
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Working Principle
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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
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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
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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
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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.
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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.
LIGO
The 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
3 Absorber Focus
Coil Modules
4 RF Cavities/module
Tracker Module
MICE Infrastructure
• The MICE facility requires construction of major
infrastructure to support the muon beamline and
cooling channel e.g. ;
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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
MICE
Photos of Early construction/integration work on the
facility and components
T2K
The T2K experiment is a second generation long-baseline neutrinooscillation 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
TITANIUM
GRAPHITE
Ø46mm
~960mm
Ø226mm
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
Superconducting Helical Undulator
The development team with the completed 4 metre long 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.