1. A. Koçmen, Turkish Atomic Energy Authority, Eskişehir Yolu 9.km., Ankara, Turkey
2. A. Teğmen Ankara University, Faculty of Science, Dept. of Physics, Beşevler, Ankara, Turkey
3. D. Türeci 75. Yıl Anadolu Lisesi, Çayyolu, Ankara, Turkey
4. M.Ç. Güleçyüz, Ankara University, Faculty of Science, Dept. of Physics, Beşevler, Ankara, Turkey
5. R.G. Türeci, Kırıkkale University, Kırıkkale Vocational High School, Kırıkkale Turkey. E-mail: