Measurement of Cross Section for ¹⁹⁷Au(p,n)¹⁹⁷Hgm at 9.2 MeV Proton Energy

The isomer of radio mercury ¹⁹⁷Hg, henceforth referred to as ¹⁹⁷Hg^m, is a promising theragnostic radionuclide endowed with properties that allow diagnostic and therapeutic applications. ¹⁹⁷Hg^m is currently widely used as a contrast agent for nuclear medicine imaging. ¹⁹⁷Hg^m can be produced by the proton capture reaction of ¹⁹⁷Au. The high-precision measurement of ¹⁹⁷Au(p,n)¹⁹⁷Hg^m reaction cross section is of great significance for improving the safety, effectiveness and scientificity of medical radionuclide diagnosis and treatment. The proton beams were delivered by the HI-13 tandem accelerator at the China Institute of Atomic Energy, Beijing. The energy of the incident proton beam is 9.2 MeV. In this paper, the high-precision cross section measurements of ¹⁹⁷Au(p,n)¹⁹⁷Hg^m with the activation method were reported. During the irradiation process, a Keithley 6517B electrometer with an accuracy of 10-18 A was used to digitize the beam current in real time, and the water circulation cooling system controls the temperature of the target. The residual radioactivity of the target was measured by a Clover detector in a low-background shielded system after irradiation. Moreover, the functions such as time tags were added to accurately extract the net counts of the full-energy peak in the VME data acquisition system (DAQ), and combined with GEANT4 simulation to extract the absolute detection efficiency cure. The cross section at 9.2 MeV was finally extracted as 18.9(19) mb. The new data are in acceptably good agreement with the published earlier experimental data in the overlapping energy. The experimental data are also consistent with the predictions of TALYS1.9. This work provides an independent cross-test for ¹⁹⁷Au(p,n), an important data, and lays a foundation for precision medicine of radionuclide ¹⁹⁷Hgm.