In April the UK scientific community was given the opportunity at an open meeting in Oxford to hear about TESLA -the linear properties electron-positron accelerator currently being proposed by an international collaboration of high-energy physicists. It be would be built at DESY in Hamburg, and is one of a number of linear accelerator proposals being considered by the international physics community. The TESLA project is particularly exciting because it not only benefits particle physics research but also many other scientific areas such as condensed-matter physics, chemistry, biology and medical science. The multidisciplinary impact of TESLA is thus tremendous.

The heart of TESLA is a superconducting accelerator to accelerate electrons and positrons so that they collide with a total energy reaching potentially as high as 800 GeV. Electron-positron colliders are needed to explore the properties of high-energy particles and their interactions, and do so in ways complementary to machines such as the Large Hadron Collider, the proton- proton collider being built at CERN, Geneva.

The TESLA design also incorporates an additional valuable research tool -a free electron laser (FEL) which would ‘feed off’ the main accelerator. An FEL is a novel device that provides extremely intense, coherent (all light waves in the same phase) beams of X-rays in very short pulses. This new X-ray source would be more than l00 million times brighter than present-day sources. The very short X-ray pulses it would generate -of the order 10^-13 seconds’ duration -would allow researchers to follow, for the first time, many very fast chemical and biological reactions as they happen. Just as the coherence of optical laser light led to the development of holography, coherence in the X-ray region will allow molecules to imaged in new ways. As a result, the detailed structure of complex microscopic biological systems could be mapped out.

The path to the TESLA proposal extends back several years. Over the past two years particle and accelerator physicists have been meeting at a series of workshops organised by DESY under the guidance of the European Council for Future Accelerators (ECFA). The task was to map out in detail the physics potential of TESLA and to optimise the design of both the accelerator and the accompanying high-performance detector; UK physicists were prominent throughout this process. This led to the publication of a Technical Design Report in March 2001. At the same time, the report was launched with a two-day Scientific Colloquium at DESY where the technical design of the machine was presented, together with a full costing and outline construction schedule. The meeting was attended by more than a 1000 scientists, representing the wide scientific scope of the TESLA project and its international nature. The ECFA/DESY study will continue for the next two years where the detailed performance of the detector and accelerator will be further refined in the period leading up to an international decision on the future of this project.

With international support, it is possible that approval for construction could be obtained in 2003. Involvement in this project is an immense opportunity for UK science.