三步分离法制备高丰度的142La

为精确测量¹⁴²La的衰变数据，需制备出高活度、高丰度、无载体的¹⁴²La样品。为去除或降低混合裂片中放射性镧的其他同位素，依据母子体衰变关系和同一质量链上独立产额的差异，提出了“三步分离”的分离模式。以一次BaCl₂•2H₂O沉淀、两次HDEHP萃取色层分离为手段建立了快速分离¹⁴²La的化学流程，并研制了批式快速化学分离装置。流程耗时约20 min，化学回收率约80%，对其他核素的去污因数大于10³，产品中¹⁴²La与¹⁴¹La活度比大于3.5。

Preparation of 142 La From Fission Product Using Three-step Separation

To precisely measure the decay parameters of ¹⁴²La, the prepared ¹⁴²La sample must have high activity, high abundance and be free from carrier. A separation procedure with three steps was proposed to prepare the sample from fission products. In order to receive optimal results, the decay relationship of mother-daughter nuclides in the 142 mass chain and the differences of their independent fission yields need to be taken into account. The established three-step chemical procedure involves one BaCl₂•2H₂O precipitation and two HDEHP extraction chromatographic separations. A specialized set of equipment was created and used to fast radiochemically separate the ¹⁴²La in batches. As a result, the total separation lasts about 20 min, and the chemical recovery rate is about 80%. The decontamination factors for other nuclides are greater than 10³, and the activity ratio of ¹⁴²La to ¹⁴¹La is more than 3.5.