Separation and Preparation of 76Ge Isotope by Centrifuge Cascade

76Ge isotope with high abundance is broadly applied in the fields of fundamental physics research and medical radionuclides, especially in the fabrication of high purity germanium detectors to detect neutrinoless double-β decay. Numerous international research cooperation groups such as GERDA, LEGEND, MAJORANA DEMONSTRATOR and CDEX are committed to the work of detecting the 0νββ decay. According to public reports, long-term plans of these experimental projects show that more than tons of enriched 76Ge is needed to fabricate HPGe detectors. In the field of radiopharmaceutical therapy, 76Ge can be used to produce several medical radionuclides, for instance, 76As, 78Se, 74Zn, 73Zn, 62Mn, 63Fe and 71,72,73Cu, through different nuclear reactions. These nuclides can be used in positron emission tomography (PET) and medical diagnosis. The separation methods of germanium isotopes mainly include electromagnetic method, low temperature distillation method and gas centrifugation method. High abundance 76Ge isotope was produced successfully in the experiments carried out by scientists from Russia and USA in the past several decades. It is meaningful to carry out relevant work with the aim of producing 76Ge with the abundance higher than 90% domestically. In order to realize the separation and preparation of enriched 76Ge isotope, the gas centrifugation method was applied in this paper with germanium tetrafluoride (GeF4) as processing gas. The calculation results based on the step cascade model indicate that the abundance of 76Ge can be enriched from natural abundance 7.73% to higher than 90% (96.52%) after five rounds of separation. The centrifugal separation experiment was carried out on the 21-stage step cascade experimental platform with 23N0 machines and the feed stage is the 11th stage. The flow rate, cut and other operating parameters were adjusted and the separation process was formulated to optimize working conditions and separation effects. Furthermore, experimental rules were explored in order to optimize the scheme. In the first four rounds of separation, the abundance of 76Ge was enriched to 13.46%, 26.71%, 49.22% and 78.81% successively. Finally, after five rounds of separation, hundreds grams of 76Ge isotopic products with an abundance of 94.21% were obtained, which provided experience and reference for the preparation of enriched 76Ge with a domestic centrifuge cascade and its industrial production. 348 grams of enriched 76Ge product is obtained by 10.984 kilograms of raw material with a utilization rate of 39.6% on the whole. The experimental values of the abundance of 76Ge in each round of separation are slightly lower than the calculation results of step cascade, and the experimental results are in good agreement with the theoretical calculation. © 2022 Atomic Energy Press. All rights reserved.