August 1, 2010
      
                  
        
  Author(s)
  David R. Black,   Donald A. Windover,   Albert  Henins,   James J. Filliben,   James P. Cline
 
       
            
    
    
        The National Institute of Standards and Technology (NIST) certifies a suite of Standard Reference Materials (SRMs) to address specific aspects of instrument performance of powder diffractometers. This report describes SRM 660b, the third generation of this