A new source-preparation technique of phosphate conversion coating used in the determination of uranium isotope ratio by alpha spectrometry

A new source-preparation technique of uranium phosphate conversion coating was developed for the determination of uranium isotope ratio by alpha spectrometry. It was found experimentally that under the conditions of 3.14 cm² Ni-foil, 0.5 mol/L HCl, 2.5 mol/L NaCl, 0.08 mol/L KH₂PO₄, 20 g/L ascorbic acid, 25 mL initial solution, 90 ℃ constant experiment temperature, 160 r/min vibration frequency, 20 mm vibration amplitude, and 70 min deposition time, uranium less than 200 μg can be quantitatively and spontaneously converted into phosphorization film on Ni-foil. Compared to the traditional source preparation technique of electrodeposition, the technique of uranium phosphate conversion coating has the advantage of simple in electrodeposition device, easy in operation, high working efficiency, no interference in measuring lots of coexisting radionuclides such as ²³²Th, ²³⁰Th, ²²⁶Ra, ²³¹ Pa and so on in phosphating solution. The total spike recovery rate of uranium reaches 100% nearly, and the spectrum resolution is good in determining uranium isotope ratio by alpha spectrometry. (authors)