Study of synthesis of NH4HfF5 for accelerator mass spectrometry

The method of multiphase synthesis of NH4HfF5 for accelerator mass spectrometry (AMS) measurement was researched in this paper. After separation and purification progress, the HfO2 sample was made to NH4HfF5 which was measured by AMS with NH4HF2 by reaction. The results show that the extraction of α-benzoin oxime was important step for the degression of W182. The beam flux of H180fF5 - in NH4HfF5 made by multiphase synthesis was three to four times as that made by liquid-phase sysnthesis at the same condition. The sample preparation methods (multiphase synthesis or liquid-phase sysnthesis) have little impact on the ratio of W182/Hf. The ratio of W182/Hf in NH4HfF5 was as low as the order of 10-11 g·g-1. The structure of NH4HfF5 powder was characterized by XRD and XPS. The results show that there were N, Hf and F elements in NH4HfF5 powder, and Hf mainly existed in quadrivalent state (+4).