Effect of dispersive and relativistic optical model potentials on the production cross-section calculation of 225Ac from 232Th using proton energy

Targeted Alpha Therapy (TAT) is considered the best method of treatment of malignant tissues. Alpha particles have interesting properties of destroying the cancerous cells due to their short penetration and high linear energy transfer. Hence, the use of alpha emitting radionuclides allows for targeting specific cancerous cells and killing of the individual cells while minimizing the toxicity to the surrounding healthy cells. The sources of the alpha for such application are the major concern. Investigation shows that Actinium-225 and Bismuth-213 are potential candidates for the production of alpha for TAT. Because of its short halve-life, the best method of production of Bismuth-213 is through 225 Ac/ 213 Bi generator hence the study of the production of Actinium-225. Critical literature review reveals that proton bombardment of thorium-232 is the best method of producing Actinuim-225. Therefore, the theoretical calculations of the production cross-sections were conducted using a nuclear modular code Empire. The calculated cross-sections were compared with one another and with the measured production cross-sections obtained from the experimental nuclear reaction data exchange format library contained in the nuclear data section of the International Atomic Energy Agency (IAEA), to investigate the effect of optical model’s configurations and the effect of the dispersive and relativistic optical model potentials on the production cross-section. The optical models’ configurations were designated by D1, D2 and D3 respectively for models that used to calculate coupled-channel transmission coefficients for the incident channel in addition to Distorted-Wave Born Approximation uncoupled, used for coupled-channel transmission coefficients for the incident and outgoing channel in addition to Distorted-Wave Born Approximation uncoupled, and used for Distorted-Wave Born Approximation calculation for all collective levels. The potentials are dispersive and relative potential, non-dispersive and relative potential, and the non-dispersive and non-relativistic potentials. The result obtained shows that the optical model configuration used to calculate coupled-channel transmission coefficients for the incident channel in addition to Distorted-Wave Born Approximation uncoupled produces the better effect on the production cross-section. Similarly, the model with Non-Dispesive and Non-Relativistic potentials produces netter yield while the optical model with Dispersive and Relativistic potential is more physically conservative. Hence any of the optical models can be used for the calculation of the production cross-section, regardless of the dispersive and relativistic potentials of the optical model.