Professor Joost Vossebeld PhD

Personal Statement

As the head of the Liverpool Particle Physics Research Cluster, my aim is to support and expand the group's research programme to address the key unanswered questions in fundamental physics. The Particle Physics group at the University of Liverpool is one of the UK's largest Particle Physics groups, holding research grants of around £22M and operating research facilities worth £30M. With a staff complement of 54 leading academics, physicists, engineers and technologists, it trains around 60 post graduate research students. The group is active at CERN (ATLAS, LHC-b), at J-PARC (T2K, Super-K, Hyper-K), at SNOLAB (SNO+), at Fermilab (g-2, mu2e, SBND, DUNE) and at PSI (mu3e) and involved in astro-particle physics (CTA), Dark Matter (LZ) and Dark Energy searches. In recent years the group has delivered the ATLAS (SCT-endcap-C) silicon strip detector, the LHC-b VeLo tracker, the ND280 ECAL for T2K, tracking stations for the FNAL g-2 experiment and the cathode plane arrays for SBND. Currently the group is developing and building detectors and other systems for the ATLAS and LHC-b upgrades, for the Mu2e and Mu3e experiments, for LZ, HK and for DUNE.
The Particle Physics Group is an international leader in the R&D on radiation-hard silicon detectors for future experiments and upgrades. The research is performed in the unique 450 m2 Liverpool Semiconductor Detector Centre (LSDC). The group is the main user of the departmental precision manufacturing workshop and the advanced materials facility. The group also has an in-house R&D programme on read-out techniques for 2-phase Liquid Argon (LAr) detectors for future neutrino oscillation experiments and on the development of atom interferometry for precision fundamental physics.
The group is heavily invested in the physics exploitation of various experiments, searching for new physics at the energy frontier and for dark matter, and in the study of flavour physics, with quarks and with neutral and charged leptons. For further details on the Particle Physics group see: https://www.liverpool.ac.uk/particle-physics

I also continue to lead the 7-strong Liverpool team working on the development and construction of the Mu3e experiment at PSI. In Mu3e, with our collaborating partners in the UK, Germany and Switzerland, we will search for the lepton-flavour violating decay of positive muons to two positrons and an electron, with unprecedented sensitivity. If observed, this decay would provide direct evidence of new physics processes not included in today's Standard Model of particle physics. The experiment requires us to measure the trajectories of low momentum positrons and electrons at very high rates in several ultra-thin silicon layers. Assembly of the outer layers of the ultra-low-mass MuPix Pixel tracker takes place in Liverpool. Within the international project I coordinate the overall MuPix tracker project.

I have a long involvement with the ATLAS experiment at the LHC. I worked on the construction, commissioning and operation of the SCT Silicon strip tracker and analysed early ATLAS data to search for the Higgs boson. I was privileged to work on some of the analyses that allowed the experiment to announce the discovery of the Higgs boson in the summer of 2012.

In 2013 I started a new technology R&D in Liverpool to develop high-voltage CMOS pixel sensors for future particle physics experiments. Porting MAPS pixel sensors to high-voltage compliant CMOS technologies, had opened the door to tracking particles at high rates and in high radiation environments within single layers of thinned silicon. The Liverpool group works in close collaboration with international partners on device simulation, prototype design and prototype evaluation towards achieving small pixel sensors with excellent timing resolution. The first application of HV-CMOS pixel sensors technology is in the MuPix tracker for Mu3e. I continue to contribute to the CMOS R&D group which, today, has 9 members and is now led by Dr. Eva Vilella.