Tony Weidberg

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Tony Weidberg

Professor of Particle Physics

I helped to create the 4th year Particle Physics course and I currently give lectures for part of this course as well as lead class discussion. I am one of the authors for a new advanced undergraduate textbook: Particle Physics in the LHC Era.
I give graduate lectures on particle detectors.

I teach in the 2nd year electronics lab. I take Physics tutorials at St. John's college. I also supervise undergraduate project students and graduate students.

I am working on the ATLAS experiment at the Large Hadron Collider (LHC) at CERN. The SemiConductor Tracker (SCT) of the ATLAS experiment contains 6.2 million channels of silicon strips.The data from the 4088 SCT modules are read out at 75 KHz and this is achieved using 8000 radiation hard optical links operating at 40 Mbits/s. I was responsible for the R&D, assembly and integration for these links. Although the SCT detector is working beautifully, there were a very high failure rate of VCSELs (the lasers used for transmission). I led extensive studies of VCSEL reliability and we have developed alternative solutions based on commercial "optical engines" which have much better reliability. This gives us confidence in the ability to keep the SCT operational for the full expected lifetime.

I am now involved in R&D for the upgraded silicon tracker that will be required for the high luminosity operation at HL-LHC, which will require a larger and much more radiation hard silicon tracking detector. I have performed calculations to determine the speed of the electrical and optical links required to readout the data from the detector. I am working with engineers on the design and fabrication of the electrical tapes required for the new tracker. I am also involved with the R&D for high speed radiation hard optical links for the HL-LHC. In Oxford we identified suitable radiation tolerant optical fibres, cables, connectors and couplers, in the context of the CERN Versatile Link project. I am now working with engineers on studies of long-term reliability for VCSELs, transceivers and ASICs.

I have supervised ATLAS students doing simulation studies before ATLAS data was available and I have supervised two students who did precision measurements with the run 1 data

  • Sam Whitehead has measured the asymmetry of the rate of W+ compared to W- and used this to constrain the parton distribution functions in this new kinematical domain.
  • Nick Ryder measured the ratio of (Z->nu nu) + jets /(Z-> ee) + jets to make a direct measurement of the invisible width of the Z.

I will work a new student on precision ratio measurements using the new run 2 data. This will provide a model-independent search for new physics.