Other institutions of national significance, such as the Bulgarian Academy of Sciences (BAS) and the SS. Cyril and Methodius National Library are located in Sofia. BAS is the centrepiece of scientific research in Bulgaria, employing more than 4,500 scientists in various institutes. Its Institute of Nuclear Research and Nuclear Energy will operate the largest cyclotron in the country. All five of Bulgaria's supercomputers and supercomputing clusters are located in Sofia as well. Three of those are operated by the BAS; one by Sofia Tech Park and one by the Faculty of Physics at Sofia University.