HOW OLD IS IT? - ²⁴¹PU/²⁴¹AM NUCLEAR FORENSIC CHRONOLOGY REFERENCE MATERIALS

Area of Science:

• Nuclear forensics
• Radiochemistry
• Nuclear security

Background:

• Material age is a critical attribute in nuclear forensics.
• Plutonium-241 (Pu-241) is present in nuclear weapons and decays into Americium-241 (Am-241).
• The ingrowth of Am-241 serves as a reliable chronometer for nuclear materials.

Purpose of the Study:

• To verify the certification of a 38-year-old Pu-241 Standard Reference Material (SRM4340).
• To establish a well-characterized Pu-241/Am-241 standard for measurement validation and inter-laboratory comparisons.
• To validate measurement capabilities and laboratory performance in nuclear forensics.

Main Methods:

• Alpha-gamma anticoincidence counting was employed for verification.
• The decay of Pu-241 to Am-241 was utilized as a dating method.
• Certification of SRM4340 was cross-checked using established radiometric techniques.

Main Results:

• The certification of the 38-year-old Pu-241 Standard Reference Material (SRM4340) was successfully verified.
• The separation date of the material was established with a precision of two weeks from the documented date.
• The alpha-gamma anticoincidence counting method proved effective for age determination.

Conclusions:

• The verified SRM4340 provides a reliable standard for nuclear material age determination.
• Accurate age dating of nuclear materials is essential for nuclear forensics and international security.
• This work enhances the capability for inter-laboratory comparability and performance verification in the field.