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The NA31 experiment at CERN was built in the early 1980 s using the CERN SPS 400 GeV proton synchrotron .
 location: CERN; location: CERN
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 location: CERN; location: CERN