Time optimization of (90)Sr measurements: Sequential measurement of multiple samples during ingrowth of (90)Y

Evaluation of different methods for measuring 89Sr and 90Sr: Measurement uncertainty for the different methods as a function of the activity ratio

In case of a radiological emergency situation involving e.g. fission of uranium or plutonium, analysis of radioactive strontium will be of importance. The primary radionuclides of interest are ⁹⁰Sr, its progeny ⁹⁰Y and ⁸⁹Sr. A few days following an event, ⁸⁹Sr will be the predominant radioisotope of strontium. Most methods found in the literature are valid and applicable when measuring ⁹⁰Sr, but when samples contain both ⁸⁹Sr/⁹⁰Sr interference problematics arise. How these interferences are dealt with will have an effect on the uncertainty of the ⁹⁰Sr determination. This work aims at evaluating three measurement approaches, all mentioned in the literature, with respect to the measurement uncertainty when determining ⁹⁰Sr in an emergency preparedness situation and to propose a suitable measurement strategy.

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

A quick, automated and portable system for the separation and determination of radiostrontium in aqueous samples, using Sr-resin and multi sequential flow injection analysis, has been developed. The concentrations of radioactive strontium were determined by flow scintillation counting, allowing for on-line and also on-site determination. The proposed system can determine radioactive strontium at industrial relevant levels without further modification using overall analysis time of less than 10 min per aqueous sample. The limit of the detection is 320 fg·g^-1 (1.7 Bq/g).

Time optimization of 90Sr determinations: sequential measurement of multiple samples during decay of 90Y

This work presents an optimized method for the determination of multiple samples containing ⁹⁰Sr when its daughter ⁹⁰Y is measured after chemical separation and in sequence, i.e. during its decay. Consequently the measurement times will increase for each subsequent sample, since there has been a longer time for decay before measurement. Compared to a previously published approach, when ⁹⁰Y is measured during its ingrowth, the gain in total analysis time (time for ingrowth+ summation of measurement times) is not that large, particularly not for low background instruments. However, results for a large part of the samples can be delivered earlier.