This work describes the design and function of an a-box integrated laser ablation system coupled to an inductively coupled plasma mass spectrometer, designed and built at the hotlaboratory of the Paul Scherrer Institut, for the analysis of highly radioactive samples. A 266 nm Nd:YAG laser based ablation system was separated into beam generation and ablation and sample handling to avoid radiation induced defects of the hardware. The optical beam path is delivered through a window within the a-box. The focusing optics and the ablation cell suitable for handling highly radioactive samples are described in detail. The laser ablation system was coupled to a multicollector ICP-MS and evaluated by applying various laser parameters to ablate uranium dioxide reference materials. Isotope ratios were measured with a precision of 0.3% and a spatial resolution down to 10 mm. The optimized parameters were applied to spent nuclear fuel samples.

RADIOSTRONTIUM-90 ( 90 Sr) ULTRA-TRACES MEASUREMENTS nv•

The determination of trace level impurities in nuclear materials was performed by inductively coupled plasma mass spectrometry (ICP-MS). For this purpose extensive modifications of a commercial ICP-MS instrument were carried out and the operating conditions optimized. The effect of Zr, Th, U and Pu at concentrations of up to 1000 pg 8-l on the signal of various isotopes was studied. A strong signal suppression effect at concentrations higher than 100 pg 8-l was found for U and Pu. The effect of Zr and Th was found to be lower. Special effort was made to improve the detection limit for B; the detection limit for B in PuOz could be lowered to less than 1 pg 8-l.

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