1. Nuclear Reactor Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
2. Nuclear Reactor Laboratory and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
3. Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215
4. Studsvik Medical AB, S‐611 82 Nyköping, Sweden and Department of Radiation Physics, Lund University Hospital SE‐221 85 Lund, Sweden
5. Studsvik Medical AB, S‐611 82 Nyköping, Sweden and Mechanical, Nuclear and Production Engineering, Pisa University, Italy
6. Studsvik Medical AB, S‐611 82 Nyköping, Sweden and Unit of Biomedical Radiation Sciences, Uppsala University, SE‐751 85 Uppsala, Sweden
7. Studsvik Medical AB, S‐611 82 Nyköping, Sweden
8. VTT Processes, Technical Research Centre of Finland, P. O. Box 1608 FI‐02044 VTT, Finland
9. Department of Physical Sciences, University of Helsinki, FI‐00014 Helsinki University, Finland
10. Nuclear Research Institute, Rez 25068, Czech Republic
11. Nuclear Physics Institute, Rez 26068, Czech Republic