The QMUL group has designed, built and commissioned silicon detector systems for international experiments over the past 40 years. Our current silicon activities are divided into two areas: The ATLAS Upgrade Inner Tracker (ITk) and curved silicon detectors for future experiments and commercial applications via the Zero support Mass Detector (ZMD) effort, with our partners Micron Semiconductor Ltd and the Rutherford Appleton Laboratory (RAL).
Our ISO7, class 10,000, clean room is fully equipped with semiconductor test equipment including a semi-automatic probe station, an automatic wire bonder and bond puller, with non-contact metrology systems for quality control. This allows us to validate the quality of semiconductor sensors either fabricated in-house or procured from an external vendor, to assemble and wire bond out sensors to electrical circuits. We have also developed a precision visual capture system to augment visual reception tests with micron resolution. Our facility is climatically controlled and is also used for long term stability and burn in studies of sensitive instruments.
The Large Hadron Collider (LHC) at CERN will undergo a luminosity (intensity) upgrade to the so-called High Luminosity LHC (HL-LHC) later this decade. Since 2008 our group has worked on the development this instrument, where we focus on the development of part of the microstrip barrel detector system and the design of a pixel endcap system, in collaboration with our national and international partners.
Understanding the thermal impedance of a detector is vital to ensure that, in a high radiation environment, one can predict the cooling power required to operate sensors without them being damaged by thermal runaway or becoming inefficient. Our group leads the thermal simulation of the ITk strip barrel sensor detector, which is vital to ensure that there is a detailed understanding of when thermal runaway occurs and what the design overhead is for the project. This is supported by dedicated facilities for IR measurement of material thermal conductivity, along with the use of IR metrology to understand the thermal impedance of large area local support structures. The techniques we have developed in order to solve this R&D problem are widely transferable into industry led problems and allow us to perform quality control on materials and stave structures assembled by our national partners in the project.
Our precision engineering capabilities are demonstrated through our many contributions to this project. One of the highlights is assembly tooling designed and fabricated at QMUL that has been delivered to national laboratories in the UK and in the USA. This tooling is essential for precision alignment of 14 sensor modules on each side of a stave.
Ultrathin silicon is flexible, and we have almost a decade of experience in constructing curved silicon modules, following on from work with CMOS Monolithic Active Pixel Sensor (MAPS). We can routinely construct cylindrically deformed large area (100mm x 100mm) models of silicon modules using ultrathin silicon to ensure that we can make units that can be assembled into a cylindrical detector. Our current activity in this area is focused on the construction of strip detector modules, using bespoke sensors from Micron Semiconductor Ltd., building up to using large area CMOS MAPS sensors in collaboration with colleagues at the Rutherford Appleton Laboratory in Didcot. Our technology has the capability of being used for applied instruments as well as for future particle and nuclear physics experiments.