1. Joint Institute for Nuclear Research, 141980 Dubna, Russia
2. Moscow Engineering Physics Institute, 115409 Moscow, Russia
3. Khlopin-Radium-Institute, 194021 St. Petersburg, Russia
4. Institute for Nuclear Research RAN, 117312 Moscow, Russia
5. Department of Physics of University of Jyväskylä, FIN-40014 Jyväskylä, Finland