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Attendees: Gerog, Chris, Yvonne, Peter, Phil, Steve, Konstantin, Fergus, Armin, Andy, Wing, Joel Vidyo: Aidan Apologies: Joost, Glenn, Harald
It was stated in the minutes from March that no-one from the UK attended the first CLIC tracker meeting. In fact Armin (who was not present at the March meeting) had connected, and ecourages everyone to look at the excellent talk on the ALICE tracker upgrade: https://agenda.linearcollider.org/event/6695/
The Asia Linear Collider Workshop is next week in Japan. Phil and Aidan will be there, along with Dave Cussans from Bristol.
Aidan gave a nice overview of the software packages available, the expected future developments and the progress Glasgow have been making.
There are three packages, as used by ILD, SiD and CLIC. All share LCIO as a data format, but the SiD framework is substantially different from the other two. ILD and CLIC are also both switching to DD4HEP in the near(?) future, while the future of the SiD software is less certain. This is partly due to the very limited manpower available to support the SiD effort.
SiD is a natural starting point for silicon studies, and several groups (Glasgow, Bristol, Manchester) have already started playing with it. Instructions can be found on the SiD twiki https://wikis.bris.ac.uk/display/sid/From+Zero+to+SiD (These work for a clean install on a Linux machine, but other options exist such as running on the Grid with ILCDirac or using the distributed software via cvfms. Attempting to install on a Mac is not recommended).
It is still not known how easy it will be to properly include pixelated tracker sensors, or how timing information is dealt with. These are priorities for Aidan to look at.
After a long discussion it was concluded that given the timescale of this study, and despite the known disadvantages (lack of support, basic tracking algorithms, complicated workflow etc.) we would use the SiD framework. If we invest heavily in code development (e.g. alignment tools) we should ensure that it is abstracted enough to allow easy porting to the next version of the SiD software, whatever and whenever that may be.
Konstantin showed a few slides on the latest ideas on how to speed up charge transfer from a large photodiode to the sensing node in a 4T structure. The concept of using shaped implants to generate an accelerating field has been demonstrated on pixels of about 30 micron size with close to 100% charge transfer in 10ns, and can hopefully be scaled up.
Next time he will show some developments from his own work on fully-depleted CMOS.
Fergus gave an update on developments from the Arachnid and OverMOS projects.
The Cherwell sensor has a variety of different 4T architectures relevant for ILC R&D and has been progressively tested over the past few years. Test beam results are good, but not really completed.
OverMOS is targetted at ATLAS (high-radiation tolerance and high speed due to overdepletion) but has some features of interest to ILC. The first design is due back from the foundry this month, and will be tested extensively before a full engineering run (subject to funding).
Jamie's technology chart is also due for an update, and perhaps some effort can be found to simulate ILC-specific designs. It was also mentioned that RAL has a TCT laser available for edge-scanning sensors.
Peter showed slide on behalf of Joost, updating us on relevant work at Liverpool. They are working on HV-CMOS both in CLIC and AIDA, and are starting to think about low-mass trackers. They propose to start looking at some concepts such as integrated airflow distribution, box sections and so on.
Liverpool and Oxford have effort available (subject to consolidated grant outcome) for mechanical studies. We should look into the possibility of a PRD in order to get support for Andy's RAL TD team.
The developing list of design constraints and requirements is at https://wikis.bris.ac.uk/display/lcsi/Tracker+Requirements
The invitations to get a wiki account expire after a week, so please e-mail Joel if you need an account and register immediately. You then need to confirm with Joel that your account is set up he can give you read and write access to the relevant pages (this should become easier after the next Confluence update).
It was agreed that we should decide on the characteristics for a "straw man" design. This can be used for the first physics simulation and mechanical modelling, and then proper iteration towards conceptual designs can begin. These are now on the twiki: https://wikis.bris.ac.uk/display/lcsi/Straw+Man+Design and Wing will start on a basic CAD representation.
The date of the next (virtual) meeting was agreed as Wednesday 13th May at 1pm.