Evaluation of The Nuclear Reaction Cross Sections to Produce 211At: A Promising Alpha-Emitting Radionuclide

Abstract

Conventional cancer treatments sometimes proven insufficient in eliminating tumors. (_ ^211)At is a brilliant alpha emitter with interesting characteristics to be used for modern cancer treatment, targeted alpha therapy. There are only a few centers producing this radionuclide and due to limited research being done, the progress on utilizing (_ ^211)At is less impactful. To choose radionuclides for medical applications, knowledge of nuclear reaction cross section data is vital. It can be studied theoretically using TALYS and EMPIRE. The nuclear model codes can propose theoretical cross sections which can be compared with experimental data for assurance of data. The aim of this work is to obtain recommended cross section data to produce (_ ^211)At by evaluating the relevant experimental parameters. This study employs TALYS 1.96 and EMPIRE 3.2.3 to compute the theoretical cross sections to produce (_ ^211)At via (_ ^209)Bi(?,2n)(_ ^211)At reaction within the energy range of 21 MeV to 40 MeV. The calculations involve 48 nuclear parameters combinations, consisting of 8 alpha optical model potentials and 6 nuclear level density models of TALYS 1.96 and 3 theoretical calculations representing 3 level density models of EMPIRE 3.2.3. The statistical deviation factors validate the accuracy of the evaluations for each calculated excitation function. The combination of ALPHA5 and LD5 have the best value for deviation factors making it the optimal nuclear parameters to calculate the excitation function of (_ ^209)Bi(?,2n)(_ ^211)At using TALYS 1.96 and LEVDEN 4 is the best level density model for EMPIRE 3.2.3’s calculation. The theoretical excitation functions calculated with optimized nuclear parameters are fitted with experimental data and to be averaged after fitting to generate recommended cross section data. With recommended data, the optimal energy range to maximize the production of (_ ^211)At while minimizing a radionuclidic impurity, (_ ^210)At is deduced. The optimal energy for an efficient production of this therapeutic radionuclide is 30.1 MeV in which the TTY of (_ ^211)At is 37.8 MBq/?Ah and TTY of (_ ^210)At is 0.0038 MBq/?Ah.