Diamond for actinide traces detection and spectrometry in liquids

Conference of 2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and Their Applications, ANIMMA 2013 ; Conference Code:102802; International audience; 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 $\alpha$-particle detector (Si or Si-PIN diode), followed by $\alpha$-particles detection using front-end nuclear electronics. After $\alpha$-particles counting by 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 $\Delta E_{FWHM}$/$E_\alpha$ = 2.3% for pulse height spectra of 5.486 MeV α-particles emitted by $^{241}$Am, measured directly in water.