Analytical approach to understand laser isotope separation process of Yb-176 for Non Carrier Added (NCA) radioisotope Lu-177

Lutetium-177 (¹⁷⁷Lu) has emerged as a promising short range β-emitter for targeted radiotherapy. There are two ways to produce ¹⁷⁷Lu. One is the Carrier Added (CA) method in which ¹⁷⁶Lu is used as a source material and second method is Non Carrier Added (NCA) wherein enriched ¹⁷⁶Yb is used as a source metal in nuclear reactor. Natural abundance of ¹⁷⁶Yb is only 13%, however the isotopic purity requirement of source material concentration is more than 95% of ¹⁷⁶Yb. Laser Isotope Separation (LIS) method has been intensively used worldwide to produce high enriched ¹⁷⁶Yb (more than 95%) in weighable amount (10-20 mg/hr). At Bhabha Atomic Research Centre (BARC), multiple experiments for LIS of ¹⁷⁶Yb have been conducted in RIS facility of BTDG. ¹⁷⁶Yb 97.1% with ¹⁷⁴Yb 1.09% has been obtained at mass production rate 5 to 10 mg/hr. In this paper a mathematical model of the LIS process applicable for high enrichment factor with mg quantity as required for medical isotopes is presented. Data generated from the model was compared with experimental results. (author)