SCT Endcap C
The Liverpool ATLAS group was involved in the construction, testing, installation and commisioning of the SCT Endcap C.
The organisation of the international programme for the production of forward modules across 15 institutes was led by Liverpool. This followed Liverpool's central role in designing the wedge shaped sensors for the forward region and defining the forward module design.
The group's role in the production of the SCT Forward Modules was two-fold. Modules produced by outside institutes were acceptance tested before they were mounted onto discs. This was done in parallel with the production and full characterisation of modules bonded in-house.
The Liverpool group had responsibility for wire-bonding 300 double-sided modules (each with 2310 bonds per side) following a thorough initial visual inspection. The modules were then thermally cycled and their metrology checked against initial measurements using the SmartScope. The modules were then characterised, with measurements being performed of I/V, full ASIC functionality, timing and noise. The electronics test system, which exercised the hybrids through the opto-readout, but allowed use of the electrical connections, was designed by Liverpool. A yield of 94% was achieved for the modules bonded at Liverpool.
The design of the tooling to enable modules to be mounted onto discs was finalised following prototyping for the 3 different types of module. The tooling was then manufactured and commissioned by Liverpool.
The discs were prepared with cooling pipes, precision mounting blocks, electrical services and optical fibres at RAL. On arrival in Liverpool, a number of acceptance tests were performed, including a visual inspection, leak tests, tests of the electrical connections, tests of the optical fibre connections and metrology of the mounting pins using the Coordinate Measuring Machine.
Each disc was mounted in the assembly jig and the modules were then assembled. A total of 988 modules were successfully mounted onto 9 discs with no losses.
The test box to allow the discs to be cooled and electronically tested in the large environmental chamber, with thermal measurements taken using the thermal camera, was designed, manufactured and commissioned in-house, including the design and manufacture of the heat exchangers and the installation of all the necessary pipe work for the evaporative cooling system. The installation of cables, optical fibres, power supplies, slow controls and SCTRODDAQ completed the infrastructure.
Each complete disc was transported to, and then mounted in, the test box in the environmental chamber. The evaporative cooling plant supplied coolant at -25°C and the functionality of each module was checked. The characterisation of the full disc was then performed and thermal images taken and analysed to confirm the cooling performance.
Noise distributions for all the 988 mounted modules. The different colours indicate the four different module types. Each disc was mounted in the assembly jig and the modules were then assembled. A total of 988 modules were successfully mounted onto 9 discs with no losses. Each complete disc was transported to, and then mounted in, the test box in the environmental chamber. The evaporative cooling plant supplied coolant at -25°C and the functionality of each module was checked. The characterisation of the full disc was then performed and thermal images taken and analysed to confirm the cooling performance.
Please see the following link for detailed test results
The mounting of the discs into the support cylinder was undertaken in collaboration with Glasgow, Lancaster, Manchester, RAL and Sheffield. Many engineering tasks were performed in assembling the cylinder, with modifications to the thermal feed-through, the attachment of various mounting clips for the services etc. being necessary followed by extensive mounting and testing of all services (cooling, low-mass electrical connections, optical fibres).
The original transport frame for the end-cap was designed at NIKHEF. Major changes to the design were made necessitating a trial run to assess the proposed procedure for loading and unloading and to evaluate the effectiveness of the design in reducing shocks to EndCap-C. The results demonstrated the feasibility of the transport of EndCap-C to CERN which was completed successfully in February 2006.
On 18th June 2007 Endcap C was moved from the surface building and lowered into the ATLAS experiment. The next day it was installed into its final position inside the calorimeter of ATLAS.
The Liverpool group were heavy involved with the fibre/power cable connections and testing and are currently working on calibrating and commissioning the detector
- SCT Endcap C Disk 6 -
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