TRIAC Progress Report - KEK

gamma rays. 111 In, which decays to 111 Cd with T1/2 = 2.8 days by emitting two cascade
gamma rays of 171 and 245 keV via an excited state of 85 ns, is well known as a probe
complying with the above condition. By accelerating 111 In by the TRIAC, the
implantation depth can be controlled, enabling us
to investigate the properties of material at
different depths. As the first step, we implanted
111
In into a highly oriented pyrolytic graphite
(HOPG) with 30 keV employing only the
JAEA-ISOL.
An enriched 96 Mo target of 3 mg/cm 2
thickness was irradiated with the 19 F beam of 95
MeV from the JAEA tandem accelerator. 111 In
produced by the fusion evaporation reaction, 19 F
( 96 Mo, 2p2n), was implanted into a HPOG plate.
Typical beam intensity was about 10 4 pps. After
20-hours implantation, we measured the
time-differential perturbed angular correlation
(TDPAC) of the cascade gamma rays.
The TDPAC spectra at four temperatures are
presented in Fig. 3-37. The anisotropy of the two
gamma rays is represented as R(t). Contrary to
the expectation of the oscillation due to the
electric quadrupole interaction between 111 In and
the extranuclear charge distribution, fast spectral
damping was observed at the respective
temperatures. The larger final isotropy at 673 K
implies the recombination and movement of
111
In in the materials. For further information,
measurements at higher temperatures are
necessary.
References
[3-1] M.J. Balbes et al., Nucl. Phys. A 584 (1995) 315.
[3-2] Z. H. Li et al., Phys. Rev. C 71 (2005) 0528018(R).
[3-3] H. Ishiyama et al., Phys. Lett. B 640 (2006) 82.
[3-4] T. Hashimoto et al., Phys. Lett. B 674 (2009) 276.
93
Fig. 3-37. TDPAC spectra of 111 Cd
( 111 In) in HPOG at 673, 473, 373, 298
K, respectively.