1. Tokamak Energy Ltd, Culham Science Centre, Abingdon, OX14 3DB UK
2. Culham Electromagnetics Ltd, Culham Science Centre, Abingdon, OX14 3DB
3. Department of Materials, University of Oxford 16 Parks Road, Oxford OX1 3PH UK
4. Oxford Instruments, Abingdon, OX13 5QX, UK