1. Quantum
Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology QST, 2-4 Shirakata,
Tokai, Naka, Ibaraki 319-1106, Japan
2. National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan
3. Institute
of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan
4. Department
of Applied Physics, Aalto University School of Science, FI-00076 Aalto, Finland
5. National University of Science and Technology MISiS, 4 Leninskiy Prospekt, Moscow 119049, Russian Federation
6. Department
of Chemistry, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea
7. Wihuri
Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014, Turku, Finland
8. Technological Institute of Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk, Moscow 142190, Russian Federation