Susumu Ohya

Nuclear Data Sheets for A = 123

The experimental results from various decays and reactions for the A=123 mass chain have been compiled and evaluated. Adopted values for the level and decay properties are tabulated. Inconsistencies and discrepancies are noted.

Nuclear Magnetic Resonance on Oriented 175Ta and 177Ta

175 Ta and 177 Ta nuclei were oriented at low temperature as dilute impurities in Fe. The magnetic hyperfine splitting frequencies ν=|µ B HF / I h | of the 175 Ta and 177 Ta ground states have been measured to be 320.45(11) and 317.552(55) MHz by using the technique of NMR-ON. Taking the known hyperfine field of 181 Ta in Fe, the magnetic moments have been deduced: |µ( 175 Ta, 7/2 + )|=2.270(45) and |µ( 177 Ta, 7/2 + )|=2.250(45)µ N . These values of the magnetic moments are discussed in the framework of the rotational model.

g -Factor of the Ground State of 73 Se

Nuclear magnetic resonance on oriented 73 Se in an iron host has been observed at about 7 mK. From resonance-shift measurement, the magnetic hyperfine-splitting frequency ν M , g -factor and magnetic hyperfine field were derived as ν M =102.61(3) MHz, | g (9/2 + )|=0.188(16) and B HF ( 73 Se Fe )=716(81) kG. The experimental values of the g -factors of the g 9/2 neutron states, in the neighborhood of the neutron number 40, are compared with the theoretical values based on the core-polarization model.

The Levels of93Zr Populated in the Decay of93Y

The decay of 93 Y to the levels in 93 Zr has been investigated with the use of Ge(Li), Si(Li), NaI, plastic and anthracene detectors in singles and coincidence experiments. Gamma-ray energies and relative intensities were carefully determined. The resulting decay scheme consists of levels at 267.0, 946.1, 1425.5, 1449.8, 1469.5, 1650.4, 1827.1, 1908.8, 2183.7, 2457.7 and 2474.7 keV. Gamma-gamma directional correlation measurement has been performed for the 679.1–267.0 keV cascade; A 2 =-0.0049±0.0213 and A 4 =0.020±0.036. The K conversion coefficient was determined for the 267.0 keV transition; α k =0.022±0.004. The spin-parity of the 267.0 keV level has been determined to be 3/2+. The proposed level scheme was dompared with the prediction of current theoretical calculations.The decay of 93 Y to the levels in 93 Zr has been investigated with the use of Ge(Li), Si(Li), NaI, plastic and anthracene detectors in singles and coincidence experiments. Gamma-ray energies and relative intensities were carefully determined. The resulting decay scheme consists of levels at 267.0, 946.1, 1425.5, 1449.8, 1469.5, 1650.4, 1827.1, 1908.8, 2183.7, 2457.7 and 2474.7 keV. Gamma-gamma directional correlation measurement has been performed for the 679.1–267.0 keV cascade; A 2 =-0.0049±0.0213 and A 4 =0.020±0.036. The K conversion coefficient was determined for the 267.0 keV transition; α k =0.022±0.004. The spin-parity of the 267.0 keV level has been determined to be 3/2+. The proposed level scheme was dompared with the prediction of current theoretical calculations.

Nuclear Magnetic Resonance on Oriented 137m,gCe and 139Ce

Nuclear magnetic resonances of oriented 137m,g Ce and 139 Ce in an iron host have been measured at 7 mK. From the resonance-shift measurement of 137m Ce, the magnetic hyperfine splitting frequency ν=|µ B HF / I h |, the magnetic moment µ and the magnetic hyperfine field B HF were derived as ν=54.25(1) MHz, \(|\mu(^{137\text{m}}\text{Ce}, \frac{11}{2}^{-})|=1.01(4)\mu_{\text{N}}\) and B HF ( 137 Ce Fe )=-38.8(10) T, respectively. The resonance frequencies of 137g Ce Fe and 139 Ce Fe at the external field of 0.2 T were found to be 188.3(5) and 208.5(5) MHz, respectively. With the measured hyperfine field, the magnetic moments of 137g Ce and 139 Ce were deduced as \(|\mu(^{137\text{g}}\text{Ce}, \frac{3}{2}^{+})|=0.96(4)\mu_{\text{N}}\) and \(|\mu(^{139}\text{Ce}, \frac{3}{2}^{+})|=1.06(4)\mu_{\text{N}}\). The measured magnetic moments are compared with the theoretical values based on the core-polarization model.

Nuclear Magnetic Resonance on Oriented 9.3 m 178Ta

The g -factor of the 1 + isomeric state of 9.3 m 178 Ta has been measured using the technique of nuclear magnetic resonance on oriented nuclei at about 7 mK. The magnetic hyperfine-splitting frequency was determined to be 201.56(22) MHz for zero external magnetic field in Ni. With a magnetic hyperfine field B hf =96.5(3) kG, the g -factor was derived as | g ( 178 Ta, 1 + )|=2.740(12). RADIOACTIVITY 178 Ta [from 178 Hf(α, 4n) 178 W(decay)]: measured I (θ, T ,ν), NMR, oriented nuclei in Ni, deduced g , recoil implantation.

NMR-ON studies on the magnetic hyperfine field at 140La in Fe

Nuclear magnetic resonance on oriented nuclei (NMR-ON) of La existing as a dilute impurity in Fe was observed for the first time. NMR-ON experiments were performed by detecting the 1596 keV γ rays ...

Observation of Muonic X-rays of Cosmic-Ray Muons Stopped in Al and Fe Targets

We successfully measured muonic X-rays of cosmic-ray muons stopped in Al and Fe targets. In order to identify the events that incoming cosmic-ray muons were stopped in the targets, a coincidence and anticoincidence system of three plastic scintillators was used. The X-rays associated with the atomic muon captures were measured with germanium detectors. Measurements using the Al and Fe targets were carried out for 33 and 16 days, respectively. A sufficient number of muonic X-ray events for identifying the elemental compositions of the target materials were clearly observed. This technique provides a means of nondestructive elemental analysis that does not require the use of particle accelerators.

Nuclear spin relaxation of extremely dilute impurities using brute-force NMRON

Brute-force nuclear magnetic resonance on oriented nuclei (BF-NMRON) was used to investigate the nuclear spin-relaxation times, T 1 , of 90 Nb in Nb and Cu, 96 Tc in Nb, 101 m Rh in Cu, and 110 m Ag in Ag with an external field of 11.922 T at about 10 mK. The observed relaxation times with known nuclear g-factors were used to estimate the converted relaxation rates, ( T 1 T g n 2 ) -1 , which were compared with those obtained from NMR and other methods. From the comparison, it was found that ( T 1 T g n 2 ) -1 of 90 Nb in Nb and 110 m Ag in Ag coincided with those of the bulk systems. ( T 1 T g n 2 ) -1 of 90 Nb in Cu was about four times larger than that of Nb bulk system. Both 96 Tc in Nb and 101 m Rh in Cu produced ( T 1 T g n 2 ) -1 values consistent with previous studies.