Proton induced reactions on ⁸⁹Y with particular reference to the production of the medically interesting radionuclide ⁸⁹Zr

Abstract

Excitation functions of the reactions ⁸⁹Y(p,n) ⁸⁹Zr, ⁸⁹Y(p,2n) ⁸⁸Zr and ⁸⁹Y(p,pn) ⁸⁸Y were measured from their respective thresholds up to 17.7 MeV, with particular emphasis on data for the production of the medically important radionuclide ⁸⁹Zr. The conventional stacked-foil technique was used, and the samples for irradiation were prepared by the sedimentation process. The excitation functions obtained were compared with those calculated theoretically using the ALICE-IPPE code. The measured data were also compared with the available literature values. From the experimental data the theoretical yields of the investigated radionuclides were calculated as a function of proton energy. The excitation function for the ⁸⁹Y(p,n) ⁸⁹Zr reaction measured in the proton energy range 5.1 to 17.7 MeV shows a pronounced broad peak in the energy range 16→11 MeV. On the other hand and because of the high threshold energy of the two other reactions ⁸⁹Y(p,2n) ⁸⁸Zr and ⁸⁹Y(p,pn) ⁸⁸Y, their excitation functions were measured only in the proton energy range 14.3 to 17.7 MeV. Differential and integral yields for the production of the three radionuclides were calculated. It was found that the suitable energy range for the production of ⁸⁹Zr is 14→9 MeV; over this energy range the ⁸⁹Zr amounts to 58 MBq/μA h. In the proton energy range provided by MGC-20 cyclotron [E_p(max)=18 MeV], only ⁸⁹Zr can be produced in a suitable activity and with a high purity. Production of ⁸⁸Zr and ⁸⁸Y needs proton energy higher than that provided by this type of cyclotron.