Radioactive Stacked Foil Analysis for Nuclear Cross-sections*

A very innovative method for cancer treatment is emerging, known as targeted alpha therapy (TAT). The goal is to target alpha-emitting radionuclides to cancerous tumors without injuring healthy tissue, using targeting vectors. One potential isotope to target carcinogen tumors is terbium-149. This isotope is of particular interest due to its unique property of having both beta (83.3%) and alpha decay (16.7%).  

This project aims to discover what other isotopes were created during the production of terbium-149 which consisted of a beam of lithium-6 on a natural samarium target at different energies. Some predictions can be made by looking at the chart of nuclides and focusing on the isotopes’ half-lives, stabilities, and properties. After a single night of beam, the foils were counted a day after irradiation, using three high-purity germanium (HPGe) detectors. Background, natural samarium foils (with thicknesses of 100 and 250 micrometers), europium-152 source, and gold foils (with a thickness of 5 micrometers) data was collected on the HPGes. To analyze these spectra, the python toolkit called Curie was used to simplify the identification and fitting of the peaks. After calibrating the spectra using the europium-152 source in Curie, the resulting isotopes can be identified. With this data we can conclude that the isotope production of terbium-149 via this method may be possible, but more measurements will need to be performed to confirm the optimal production pathway. 

The project focuses on one single night of data collected. Three detectors were used. The data was gathered a day after the reaction occurred. Each detector holds data files of background (when no beam or target are involved), natural Samarium with a thickness of 100 and 250 micrometers (Which may include different stable isotopes), Europium-152 (Used as calibration energy source), and Gold with a thickness of 5 micrometers (used as target). Giving us an approximate total of 700 runs.