Application of the ²²⁶Ra-²³⁰Th-²³⁴U and ²²⁷Ac-²³¹Pa-²³⁵U radiochronometers to uranium certified reference materials

Uranium certified reference materials (CRM) issued by New Brunswick Laboratory were subjected to dating using four independent uranium-series radiochronometers. In all cases, there was acceptable agreement between the model ages calculated using the ²³¹Pa-²³⁵U, ²³⁰Th-²³⁴U, ²²⁷Ac-²³⁵U or ²²⁶Ra-²³⁴U radiochronometers and either the certified ²³⁰Th-²³⁴U model date (CRM 125-A and CRM U630), or the known purification date (CRM U050 and CRM U100). The agreement between the four independent radiochronometers establishes these uranium certified reference materials as ideal informal standards for validating dating techniques utilized in nuclear forensic investigations in the absence of standards with certified model ages for multiple radiochronometers. (author)