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 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.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.
Required to 1) Assemble the detector 5 ATLAS SCT Tooling 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
Accurately positioning the detectors CMS
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 RICH1 E Cal
Multi Polarimeter SR (Synchrotron Radiation) Instruments 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.
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 Tracker Module 4 RF Cavities/module
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
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.