Diamond for actinide traces detection and spectrometry in liquids

We describe here a new approach for the detection and identification of actinides (Am, Pu, Cm etc) at very low activity levels in aqueous solution. The measurement consists at first in the electroprecipitation of the actinides ions as insoluble hydroxides directly onto a boron doped nanocrystalline diamond (BNCD) electrode deposited on an α-particle detector (Si or Si-PIN diode), followed by α-particles detection using front-end nuclear electronics. After α-particles counting, spectrometry, the detector can be easily decontaminated using anodization in aqueous solution to be able to be reused at once. The detection limit of the described prototype system can be estimated as low as a few mBq/L (for one day counting) to several mBq/L for 5h counting and currently achieved energy resolution amounts to ΔE_FWHM/E_α = 2.3% for pulse height spectra of 5.486 MeV α-particles emitted by ²⁴¹Am, measured directly in water.