Non-equilibrium analysis of (α,xn) reactions on heavy nuclei

Upgrade of recommended nuclear cross section data base for production of therapeutic radionuclides

The IAEA Nuclear Data Section has coordinated several actions to setup and improve a database for recommended cross sections and nuclear decay data for various charged-particle reactions that can be used for medical radionuclide production. Some of the earlier evaluations did not provide uncertainties for the recommended cross sections. Updated evaluations with uncertainty quantification for 25 reactions relevant for production of 67Cu, 103Pd, 102mgRh, 114mIn, 125I, 169Yb, 177gLu, 186Re, 192Ir and 210,211At therapeutic radioisotopes are presented. Recommended cross-section data and their uncertainties for production of therapeutic radionuclides are available on the Web page of the IAEA Nuclear Data Section at https://nds.iaea.org/radionuclides and also at the IAEA medical portal https://nds.iaea.org/medportal.

Excitation functions for 209Bi reactions induced by threshold to 50 MeV energy alpha particles

Excitation functions for ²⁰⁹Bi(α,2n)²¹¹At, ²⁰⁹Bi(α,3n)²¹⁰At and ²⁰⁹Bi(α,4n)²⁰⁹At reactions were calculated using TALYS-1.95 nuclear code from threshold to 50 MeV by invoking suitable options for level densities, nucleon-nucleus optical model potentials and alpha optical model potentials. Statistical factors were used to verify the quality of matching between theoretical model calculations and the experimental data from the EXFOR database. The TTY of ²¹¹At calculated using the excitation function of ²⁰⁹Bi(a,2n)²¹¹At reaction is compared with existing experimental studies from literature The results of the present study are important for the validation of nuclear model approaches with increased predictive power for ²⁰⁹Bi(α,xn) reactions for the production of ²¹¹At.

Validation of nuclear reaction models for incident α-particles

Two different models allowing the calculation of reaction products are confronted with data from α-particle induced reactions. Both models contain a pre-equilibrium part and an equilibrium or compound nucleus part. The models are the exciton model in form of a code written by the author and TALYS. The other model is the intranuclear cascade model in form of the Liege-Saclay formulation incorporated in the PHITS code. The data are angle-integrated proton spectra from reactions with α-particle energies below 720 MeV and excitation functions from multi neutron emission with α-particle energies below 200 MeV.

Optimisation study of α-cyclotron production of At-211/Po-211g for high-LET metabolic radiotherapy purposes

The production of no-carrier-added (NCA) alpha-emitter (211)At/(211g)Po radionuclides for high-LET targeted radiotherapy and immunoradiotherapy, through the (209)Bi(alpha,2n) reaction, together with the required wet radiochemistry and radioanalytical quality controls carried out at LASA is described, through dedicated irradiation experiments at the MC-40 cyclotron of JRC-Ispra. The amount of both the gamma-emitter (210)At and its long half-lived alpha-emitting daughter (210)Po is optimised and minimised by appropriate choice of energy and energy loss of alpha particle beam. The measured excitation functions for production of the main radioisotopic impurity (210)At-->(210)Po are compared with theoretical predictions from model calculations performed at ENEA.

Experimental study of the cross-sections of alpha-particle induced reactions on 209Bi

alpha-particle-induced nuclear reactions for generation of (211)At used in therapeutic nuclear medicine and possible contaminants were investigated with the stacked foil activation technique on natural bismuth targets up to E(alpha)=39 MeV. Excitation functions are reported for the reactions (209)Bi(alpha,2n)(211)At, (209)Bi(alpha,3n)(210)At and (209)Bi(alpha,x)(210)Po. Results obtained from direct alpha-emission measurements and gamma-spectra from decay products are compared and correspond well with earlier literature values. Thick target yields have been deduced from the experimental cross-sections and optimised production pathways for minimal contamination are presented. A comparison with the results of the theoretical model code ALICE-IPPE is discussed.