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In September , Fermi assembled his first nuclear " pile " or reactor , in an attempt to create a slow neutron-induced chain reaction in uranium , but the experiment failed to achieve criticality , due to lack of proper materials , or not enough of the proper materials which were available .
 Fermi
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Fermi