The radioisotope implanter Production and implantation of 111InO- ions Implantation of the 111In/Cd probe as InO- ion for radioisotope tracer studies

Nuclear condensed matter techniques such as Perturbed Angular Correlation (PAC) spectroscopy, Low-Temperature Nuclear Orientation (LTNO) and Nuclear Magnetic Resonance on Oriented Nuclei (NMRON) require radioisotope tracers to be introduced into a material host as probing nuclei. The low energy ion implantation of a radioisotope probe has several advantages over other techniques, such as minimal sample damage, accurate dosimetry of the introduced nuclei, and a high degree of control over the implantation depth. Since a cesium-sputtering, negative ion source [1,2] offers greater versatility and extended operation, a 50- 155 keV ion implanter based on such a source has been equipped and commissioned for radioisotope implantation. In the work presented here the use of a versatile cesium-sputtering, negative ion source (SNICS-II [3]) for the implantation of the standard radioisotope probe 111In/Cd as molecular, negative 111In16O- ion has been studied in detail. The efficacy of this approach for nuclear condensed matter physics has been tested on several materials using PAC, LTNO and NMRON. Cs-sputtering negative ion source Radioisotope tracer studies with 111In/Cd Conclusions • Successful development of negative ion implantation of 111In/Cd using a cesium-sputtering source. • Implanted activities of up to 2.3 µCi have been achieved for a variety of samples. This is sufficient for nuclear condensed matter spectroscopy. • The 111InAg NMRON resonance was measured as 75.08 MHz. • For the setup used, the flux of the radioisotope ions 111In16O- (A = 127) is seven orders of magnitude smaller than that for the molecular ion 115In16O- of the corresponding stable indium isotope. • The implanted ion flux, however, is dominated by parasitic ions of the same mass number A=127, causing modifications of radiation-sensitive materials such as indium nitride