33118
The isotope Am ( half-life 141 years ) has the largest cross sections for absorption of thermal neutrons ( 5,700 barns ) , that results in a small critical mass for a sustained nuclear chain reaction .
 location: Am
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Am 
Answer:
 location: Am