Dirty Bombs
Nuclear bombs are expensive to make and require highly sophisticated industrial facilities. However, many terrorist groups would be content with causing a mass panic, and maybe scaring the whole population of a city to flee. They may prefer to use a 'dirty nuclear bomb', than a proper atom bomb. Many people will only hear the words 'nuclear bomb' and run. A dirty bomb uses an amount of radioactive material, maybe powdered or granulated, packed with an explosive.