Professional Career
Tim Sumner obtained his first degree in Physics from Sussex University in 1974. His DPhil in Experimental Physics was then carried out partly at Sussex University and partly at the Institut Laue-Langevin in Grenoble helping to start up an experiment to search for the electric dipole moment of the neutron using ultra-cold neutrons. In 1979 he moved to Imperial College to take up a Research Associate placement within the Cosmic-Ray and Space Physics group to work on instrumentation for high-energy gamma-ray astonomy. In 1984 the group became involved in the x-ray satellite ROSAT and Tim Sumner became the local project manager responsible for the delivery of flight hardware. ROSAT was launched in 1990. At about the same time he was made a lecturer within the group which had by then changed names to the Astrophysics group and he started two new research lines; direct dark matter searches and gravitational physics measurements using space missions.

Direct dark matter searches began within the so-called UK Dark Matter Collaboration and started out with NaI based instruments and more recently with xenon-based instruments. Tim Sumner was Spokesperson for the UKDMC from 2002-2007. In 2000 he initiated the international ZEPLIN-III dark matter search experiment which was carried out between 2000 and 2011 in the Boulby mine in the UK. He was PI and Spokesperson from 2000-2010. The experiement achieved some of the best results in the world. The next phase involved collaboration with our US colleagues on the LUX and LUX-ZEPLIN (LZ) projects carried out in deep Davis Cavern in the Sanford Underground Research Laboratory (SURF) at Lead, South Dakota.  Currently (2025) world leading results are being published from the on-going LZ experiment, and plans are being laid for its planned successor, XLZD.

The work on space missions included LISA, a gravitational wave observatory in space, and its precursor, LISAPathfinder,  STEP, a mission to test the equivalence principle in space and GAUGE which is was a proposal to the European Space Agency. As a member of the LISA International Science Team, he was involved in the development of the LISA mission since its inception in the early 1990s. His team at Imperial College provided flight hardware for the technology demonstrator mission, LISAPathfinder, which was successfully launched in 2015 and fuflfilled all mission science and technology objectives.  This pave the way for LISA to be initiated with ESA and its development is inderway.  STEP was a proposed ESA/NASA mission with Tim Sumner as the European PI.  Altough not successful as a proposal in its own right, it did spawn a new mission, MICROSCOPE, which was flown in 2016 by CNES/ESA.  Tim Sumner was invited onto the science working group and the mission has now published the best upper limit to equivalence principle violations - a truly pioneering result.  Meanwhile he had proposed GAUGE to ESA as a mission in fundamental physics to probe the interfaces between gravity and quantum mechanics.

Tim Sumner was promoted through Senior Lecturer, Reader and eventually to Professor in Experimental Astrophysics in 2001.