Ar-37 atoms were produced via the Cl-37(p, n)Al-37 reaction using the 30 MeV proton beam of the Cyclone 30 cyclotron of the UCL and a NaCl target. After ionization, Ar-37(2+) ions were implanted at 20 keV into 20 mu m thick Al foils. The number of Ar-37 atoms in the layers was determined by measurement of the 2.62 keV KX-rays (emitted during the EC-decay. of Ar-37) with a gas-flow proportional counter. Under vacuum and under intense thermal neutron irradiation, the implantation was found to be stable. Furthermore, the layers were found to be suited for (n, p) and (n, alpha) measurements.
Wagemans, C., Loiselet, M., Bieber, R., Denecke, B., Reher, D., & Geltenbort, P. (1997). Preparation, characterization and testing of implanted Ar-37-layers. Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment, 397(1), 22-25. https://doi.org/10.1016/S0168-9002(97)00587-1 (Original work published 1997)