Characterization of High-Energy-Heavy-Ion-Induced Defects in GaAs by Positron Annihilation

Abstract

The defects induced by 64 MeV1'F ion irradiation to a fluence of 4.3x1016/cm2 are investigated in GaAs by positron annihilation lifetime technique. Di-vacancies are created by the irradiation. The formation of triand quadri-vacancies is observed during thermal annealing. The di-, triand quadri-vacancies are annealed away at 350, 550 and 800' C, respectively.

Study of magnetic-rotation in 82 Rb by g -factor measurements

“…The g-factors of four intra-band states in the magnetic-rotational band built on the 11-state in 82 Rb were determined by the TMF-IMPAD (transient magnetic field-ion implantation perturbed angular distribution) method [8,9] . The magneticrotational states in 82 Rb were populated by the fusion-evaporation reaction 60 Ni( 27 Al,4pn) 82 Rb with a 130 MeV Al beam from the HI-13 tandem accelerator.…”

“…The schematic drawing of the TMF-IMPAD setup is shown in Fig. 2 [8] . A three layer target assembly of 60 Ni-Fe-Cu and a Ta beam stopper 2 mm from the target in the down stream were located in a "T" shaped bronze target chamber between the two pole tips of the polarizing electromagnet.…”

“…In case γ ray peaks of interest are not well separated, gated spectra were generated. The nuclear precession of a state was inferred from a double ratio obtained through single ratios ρ(±θ i ) formed with the counting rates of an adjacent pair of detectors at ±θ i for a observed transition [8,11] . The γ ray counts were obtained from the singles or gated spectra.…”

Proton alignment in 82 Sr investigated by g -factor measurements

“…The details of the TMF-IMPAD can be found in Ref. [3]. The rotational band states in 82 Sr were populated by the fusion-evaporation reaction 58 Ni( 28 Si, 4p) 82 Sr with a 110 MeV Si beam from the HI-13 tan-dem accelerator at China Institute of Atomic Energy.…”