Due to federal restrictions contained in the current National Defense Authorization Act, citizens of the People's Republic of China-including the special administrative regions of Hong Kong and Macau-as well as citizens of the Islamic Republic of Iran, the Democratic People's Republic of Korea (North Korea), and the Russian Federation, who are not Lawful Permanent Residents ("green card" holders) are prohibited from accessing facilities that support the mission, functions, and operations of national security laboratories and nuclear weapons production facilities, which includes Los Alamos National Laboratory. At the Los Alamos Neutron Science Center (LANSCE), engineers, technologists, technicians, and designers operate and modernize an 800-MeV proton accelerator complex that supports national security, isotope production, proton radiography, materials research, neutron science, future accelerator missions, and more.