Vacancy trapping at111In in tungsten

TDPAC measurements were carried out in tungsten foils and single crystals using implanted111In as a probe nucleus. After damaging the bcc tungsten lattice by heavy ion implantation, electron- and proton-irradiation the trapping of three different defects in the temperature range 293–1,000 K was observed. They were characterized by quadrupole interaction frequencies of v Q 1 = 142(2) MHz, v Q 2 = 181(5) MHz and v Q 3 = 263(5) MHz. The largest fraction of In nuclei experiencing electric field gradients corresponding to v Q 1 and v Q 2 was reached at app. 630 K whereas for v Q 3 this maximum appeared at app. 850 K. The defect configurations producing the different electric field gradients could be identified as a monovacancy trapped in a nearest neighbour 〈111〉 position (v Q 1 ), a double vacancy consisting of two adjacent vacancies in the nearest neighbour shell of the probe atom (v Q 2 ) and possibly a larger cluster (v Q 3 ).