Takayoshi Horiguchi

Changes of the Nuclear Charge Distribution of Nd, Sm, Gd and Dy from Optical Isotope Shifts

Isotope shifts and hyperfine structures in 28 optical transitions for 28 stable isotopes of Nd, Sm, Gd and Dy were measured by means of the atomic-beam laser-spectroscopy. The nuclear parameter λ was obtained from the isotope shift measurement for all the stable nuclei with the improved accuracy. The λ values were analyzed by using the Fermi distribution for the nuclear charge density. As a result, the diffuseness at the nuclear surface or the hollow depth near the center of nucleus in the charge distribution depends on the neutron number. The values of δ and also δ were determined. It is shown that λ is a good probe into the systematic change of the nuclear charge distribution.

Excitation functions of proton induced nuclear reactions on 85Rb

Abstract Excitation functions for the ( p , xn ) ( x =3−5), ( p , pxn ) ( x =1−4) and ( p , α 3 n ) reactions on 85 Rb with 14–70 MeV protons have been measured by means of the activation method. Enriched 85 RbCl targets were irradiated with energy-analyzed protons from the AVF cyclotron at Osaka University. Disintegration rates of product nuclides were obtained from intensities of selected γ-rays with calibrated Ge(Li) detectors. Thick target yields of 81 Rb for medical use and other radioactive products were calculated from measured excitation functions. The calculated thick target yield of 81 Rb was 31.2 mCi μA −1 h −1 at E p =70 MeV. The thick target yield of 81 Rb chemically separated from 81 Sr, by the reaction 85 Rb( p , 5 n ) 81 Sr( β + , EC) 81 Rb, was obtained to be 2.3 mCi μA −1 h −1 at 96.4 min.

Excitation function of Ge(p,xnyp) reactions and production of 68Ge

Abstract Cross sections for the Ge(p,xn) 71–74As, (p,pxn) 68.69Ge, (p,αxn) 66.67Ga and (p,αpxn) 65Zn reactions were measured by the activation method in the proton energy range of 19–64 MeV. The thick target yields of product nuclides were estimated by using the observed excitation functions. The thick target yield of 68Ge at 64 MeV was 48 μCi/μA·h in the optimal irradiation condition (Ep = 64 → 28 MeV, target thickness of 1.8 g/cm2). As a result, the proton reaction on germanium is a useful reaction to produce a large amount of 68Ge for the positron computer tomograph in medical diagnosis.

HYPERFINE STRUCTURE AND ISOTOPE SHIFT IN ER I BY THE ATOMIC-BEAM LASER SPECTROSCOPY

Isotope shifts of 5 transitions from the 3 H 6 and 3 F 4 levels of the ground configuration 4 f 12 6 s 2 in Er I were measured for the stable isotopes with A =162-170 by the atomic-beam laser spectroscopy. Hyperfine constants A and B of 7 atomic levels were determined. Changes of mean square nuclear charge radii δ and mean square nuclear deformation parameters δ were deduced. The deformations of 164-170 Er were found to be mainly quadrupole and contributions of higher order deformation parameters for 162 Er were estimated. J -dependence of isotope shifts in the (6, 1) term of 4 f 12 6 s 6 p was found. It is concluded that the J -dependence was caused by the crossed-second-order effect in which the field shift has dominant contribution.

Hyperfine structure near the 13–1 band head in the B–X transition of 127 I 2

Hyperfine structure of the rovibronic transitions R(0)–R(10) and P(1)–P(5) in the 13–1 band belonging to the B–X system of 127I2 was studied by rectangular-crossing molecular-beam laser spectroscopy. The full width at half-maximum of the observed lines was 5 MHz, which corresponds to a resolving power of 108. Not only allowed transitions ΔF = ΔJ but forbidden transitions ΔF = 0 and ΔF = −ΔJ were identified, and absolute hyperfine coupling constants of the rovibronic states (J = 0–10) in the B(v′ = 13)−X(v″ = 1) transition were determined. In addition, the relative line strength of each hyperfine transition was compared with the theoretical value.

Systematic Study of Fine and Hyperfine Structures in Pr I by Doppler-Free Atomic-Beam Laser Spectroscopy

Atomic spectra of neutral praseodymium (Pr I) have been measured by means of the atomic-beam laser spectroscopy. Hyperfine structures of 34 atomic transitions in the wavelength range from 544 nm to 596 nm were resolved and hyperfine constants A and B were determined for 57 levels. Out of them, 18 transitions were found to be new ones and the energies and the electronic total angular momenta of 11 fine structure levels were determined for the first time.

Population of the Metastable State of Yb I by an Electric Discharge

An atomic beam oven of a discharge type is constructed and the performance in populating a metastable state of Yb I is examined. The relative populations of the ground state 4f146s21S0 and the metastable state 4f135d6s2 (7/2, 3/2)5 of Yb I are measured for the first time by the laser-induced fluorescence method. It is found that the population of the metastable state increases with the discharge current and that of the ground state decreases to 30%. The method is also applicable for other elements.

Measurement of Hyperfine Structure of the 4f35d 5G-4f36p 5H in PrII by Collinear Laser-Ion-Beam Spectroscopy

The hyperfine structure of the transitions 4 f 3 ( 4 I o )5 d 5 G 2 o -4 f 3 ( 4 I o )6 p 5 H 3 (λ=601.94 nm) and 4 f 3 ( 4 I o )5 d 5 G 3 o -4 f 3 (^4I^o)6 p ^5H_3 (λ=604.83 n m ) o f P r I I h a s b e e n m e a s u r e d b y c o l l i n e a r l a s e r - i o n - b e a m s p e c t r o s c o p y . T h e m a g n e t i c - d i p o l e c o n s t a n t A a n d t h e e l e c t r i c - q u a d r u p o l e c o n s t a n t B o f t h e l e v e l s i n v o l v e d h a v e b e e n d e t e r m i n e d t o b e : A ( M H z ) B ( M H z ) 4f^3(^4I^o)5 d ^5G_2^o 1703.2±0.8 -14.1±5.8 4f^3(^4I^o)5 d ^5G_3^o 932.8±2.2 -15.1±6.6 4f^3(^4I^o)6 p ^5H_3 1028.7±1.0 -14.3±2.5.

Observation of Stark-Induced Electric Dipole Transition in Atomic Samarium with Optical Double Resonance

The Stark-induced electric dipole ( E 1) transition for a high-lying odd-parity level in atomic samarium (Sm) was observed with an optical double-resonance technique as a preliminary study for measuring parity nonconservation (PNC). While a pump laser was locked to an E 1 transition from the 0-cm -1 to 15650.55-cm -1 levels, a probe laser was tuned to the parity forbidden transitions under static electric field. For the probe transition from the 15650.55-cm -1 to 28233.08-cm -1 levels, we have observed the Stark-induced E 1 transition. In order to investigate the contribution of the 28233.08-cm -1 level to the Stark-induced E 1 transition, the tensor polarizability was measured. We have found that the observed Stark-induced E 1 transition is anomalously strong compared with the one estimated from α 2 and an E 1 transition measured as a reference. The transition is one of candidates for improving the precision of the PNC measurements.

Stark and Zeeman Spectroscopies of Sm \captionsize I from Metastable-State Atomic Beam Produced by Electric Discharge

Hyperfine structures, isotope shifts, Stark and Zeeman effects of 5 transitions in Sm \captionsizeI are investigated by means of atomic-beam laser spectroscopy. We measure the transitions from 10801.10- and 12313.11-cm -1 metastable levels with 4 f 6 5 d 6 s configuration to 27925.31-, 28704.25-, 29041.31- and 30753.65-cm -1 odd-parity levels, which are candidates in order to measure parity nonconserving effect in Sm. Hyperfine constants A and B for odd-mass isotopes 147 Sm and 149 Sm are obtained except for 30753.65-cm -1 level. Isotope shifts of the transitions are determined and specific mass shift and field shift are also derived by King-plot analysis. Stark splitting is resolved for the transition between 12313.11- and 30753.65-cm -1 levels, and the tensor polarizability of the upper level is determined to be α 2 = 535(12) kHz/(kV/cm) 2 . From Zeeman splitting, g -factors are precisely determined for 4 levels.