Method for determination of Actinium-227 in Actinium-225

1 . A method for determination of Ac-227 in Ac-225, the method comprising:

measuring Ac-227 in Ac-225 via an indirectly produced Ra-225/Ac-225 parent/daughter.

2 . A method for determination of Ac-227 in Ac-225, the method comprising:

providing a purified Ra-225 stock,

sampling the purified Ra-225 stock to determine Ac-225 and/or Ac-228 content;

extracting of actinium isotopes from the Ra-225 stock to generate a Stock A;

resting Stock A to allow the Ac-227 to decay to Th-227;

adding a Thorium tracer to Stock A;

chemically isolating Th-227 and the Thorium tracer from other impurities including actinium;

mounting thorium isotopes onto an alpha counting disc;

counting the alpha disc using alpha spectroscopy counting equipment to determine Th-227 quantity and tracer recovery %; and

determining an amount of Ac-227 in Stock A by using the counts.

3 . The method according to claim 2 , wherein the Thorium tracer is selected from the group consisting of Th-228, Th-229, Th-230, Th-231, Th-232, Th-234, and a combination thereof.

4 . A method for determination of Ac-227 in Ac-225, the method comprising:

providing a purified Ra-225 stock,

sampling the purified Ra-225 stock to determine Ac-225 and/or Ac-228 content;

extracting of actinium isotopes from the Ra-225 stock to generate a Stock A;

resting Stock A to allow the Ac-227 to decay to Th-227;

adding a Th-230 tracer to Stock A;

chemically isolating Th-227 and Th-230 from other impurities including actinium;

mounting thorium isotopes onto an alpha counting disc;

counting the alpha disc using alpha spectroscopy counting equipment to determine Th-227 quantity and Th-230 recovery %; and

determining an amount of Ac-227 in Stock A by using the counts.