g-factor of the second 4+ state in24Mg

The transient field technique has been used to determine theg-factor of the 4 ₂ ⁺ state at 6.010MeV excitation in²⁴Mg. The deduced value ofg=+0.5(4) is consistent with collective model expectations. Further, the equality within experimental accuracies, of the g-factors of the 2 ₁ ⁺ , 2 ₂ ⁺ , 4 ₁ ⁺ and 4 ₂ ⁺ states agrees with theoretical predictions for thisT=0 self-conjugate nucleus, in contrast to the results for²⁰Ne.     

g-factors of the ground state rotational band of158Dy

Theg-factors of the four lowest states of the ground state rotational band of¹⁵⁸Dy have been determined asg(2 ₁ ⁺ )=+0.362(23),g(4 ₁ ^su+ )=+0.340(20),g(6 ₁ ^su+ )=+0.207(36) andg(8 ₁ ^su+ )=+0.21(11). Theg-factors of the 2⁺ and 4⁺ states were measured by the IPAC method with radioactive samples of 2.4 h¹⁵⁸Er in external magnetic fields. To investigate the higher states, for the first time an on-line γ—γ IPAC experiment was performed with the reaction¹⁵⁶Gd(α, 2n)¹⁵⁸Dy by use of the static hyperfine field of DyGd.     

The g-factor of the Jπ=12+ isomeric state in188Hg

Using the reaction¹⁷⁵Lu(¹⁹F, 6n) theg-factor of the¹⁸⁸Hg isomeric state (J ^π=12⁺,T _1/2=135 ns) has been measured with the TDPAD method. The experimental value g=?0.168(10) supports the interpretation of an almost pure (vi13/2)^?2 configuration for this isomer.     

Coulomb excitation studies of 160Dy, 162Dy and 164Dy

Coulomb excitation measurements with ¹⁶O and ⁴He projectiles have been performed on ¹⁶⁰Dy, ¹⁶²Dy, and ¹⁶⁴Dy. The ground-state rotational bands up through the 8⁺ member were observed in the ¹⁶O experiments. The measured excitation probabilities yield B(E2; I → I ?2) values which are generally in agreement with the rotational predictions except for the 6⁺ → 4⁺ values. In each nucleus, probabilities for exciting the 2⁺, 4⁺, and 6⁺ members of the γ-vibrational band were measured and compared with calculated results. The B (E2; 0⁺ → 2⁺γ) values were measured in experiments involving ⁴He ions. The K^π = 2^? octupole band was observed in each nucleus in addition to 1^? bands in ¹⁶⁰Dy and ¹⁶²Dy. Excitation probabilities were analyzed in an attempt to extract B(E3) values.     

g-factor of the 9/2+ isomeric state in 65Ni from transfer reaction

We report a measurement of the g-factor of the I ^π = 9/2⁺, t _1/2 = 22ns isomer in ⁶⁵Ni. The state of interest was populated and spin-oriented using a single-neutron transfer on an enriched ⁶⁴Ni target. The value, which was obtained, g(9/2⁺,^65m Ni) = - 0.296(3) is well in agreement with the g-factors of the other 9/2⁺ states in the region and with large-basis shell model calculations. The known g-factor of the 9/2⁺ isomer in ⁶³Ni was used in order to verify the strength of the hyperfine field of Ni( Ni) at room temperature.     

g-factor of the first excited 4+ states in156Gd and158Gd

Relative g-factor of the first 2⁺ and 4⁺ states have been measured with the transient field technique in¹⁵⁶Gd and¹⁵⁸Gd. The precession of gamma rays depopulating the levels under study were observed, after passing through thin polarized gadolinium. The observed values agree with the predictions of the rotational model, i.c. g(4⁺)= g(2⁺), while contrasting the hypothesis that in¹⁵⁶Gd the g-factor of the 4⁺ is reduced with respect to the 2⁺, because of rotational alignment.     

The g-factor of the yrast 4+ state in 20Ne from transient-field precession measurements

Transient field precessions of the first excited 2⁺ and 4⁺ states in ²⁰Ne nuclei traversing polarized gadolinium have been measured. The deduced g-factor of the 4⁺ state, g = + 0.08(20), agrees with our earlier reported value of g = ? 0.10(19) measured in iron by the same technique. The significant reduction in the value of the $\text{g-}\text{factor}\text{,}\text{g}\text{?}\text{= ? 0.01(14)}$, relative to that of the 2 ⁺ state, g = + 0.54(4), is incompatible with the pure T = 0 character expected for low-lying states in this self-conjugate nucleus. In addition, the lifetime of the 4⁺ state has been measured to be τ = 95(13) fs, in agreement with a previous measurement.     

Properties of octupole-vibrational bands in the 160Dy nucleus

The mixing of octupole-vibrational bands in the ¹⁶⁰Dy nucleus is analyzed within a phenomenological model that involves Coriolis coupling. The energies of levels in the bands, the reduced probabilities for E1 transitions from the octupole-vibrational bands to the ground-state and γ bands, and the ratios of the reduced probabilities for these transitions to the neighboring levels of the ground-state band are calculated. Satisfactory agreement with available experimental data is reached.     

The 2+-2+ transition of 879 keV in160Dy investigated by electron-gamma directional correlation

e-γ directional correlation measurements of 2⁺(879 keV)2⁺(87 keV)0⁺ cascade in¹⁶⁰Dy have been made and the magnitude of electric monopole to quadrapole mixing ratio for 879 keV transition was found to beq _k =?0.03(10) for λ=0 (λ-according to Hager-Saltzer definition).     

Tm3+单掺杂及Tm3+, Dy3+共掺杂YP1-xVxO4荧光粉的光谱性质

采用共沉淀法制备了Tm³⁺单掺杂及Tm³⁺,Dy³⁺共掺杂的YP_1-xV_xO₄荧光粉材料。给出了样品的XRD谱,获得了样品的SEM照片,对其发射和激发光谱也进行了测量。结果发现,随着钒酸根含量的增加,样品的激发带发生红移,这样的激发带能够满足白光LED用荧光粉的激发要求。在Tm³⁺,Dy³⁺共掺杂的样品中观测到了全色的发射,并且红、绿、蓝三个发射组分的比例也可以调整。我们计算了不同样品的色坐标,发现均在白光范围内,可见该体系样品有希望成为一种全色发射的白光LED用荧光粉。     

Gyromagnetic ratios of the 4+ and 6+ rotational states of184W

The nuclear Larmor precession has been observed for the 2⁺, 4⁺ and 6⁺ rotational states of¹⁸⁴W in the hyperfine field of WFe by application of the TDPAC and the IPAC techniques. A carrier free radioactive source of^184m Re alloyed with high purity iron was used for all three measurements. From the Larmor precession observed in the 2⁺ state by TDPACω _L = 944(15) MHz and the knowng-factor the hyperfine fieldB _{300 K} ^hf (WFe)=?69.6(27)T was derived. The deviation from the result of a spin echo experiment with¹⁸³WFe extrapolated to room temperature may be caused by the Bohr-Weisskopf effect (hyperfine anomaly). IPAC measurements with the same sample polarized in an external magnetic field of 1.6T gave for the 4⁺ and 6⁺ rotational states: ω _L τ(4⁺)=0.0609(22) andω _L τ(6⁺)=0.00735(102). By use of experimentalB(E2)-values theg _R -factors were derived asg _R (4⁺)=+0.276(26) andg _R (6⁺)=+0.281(45). The directional correlation of the 537?384 keVγ-γ cascade has been analysed in terms of anE1/M2/E3 mixture for theK-forbidden 537keV transition. We obtained the mixing ratiosδ(M2/E1)=±0.086(16),δ(E3/E1)=?0.028(5) with the sign convention of Krane and Steffen.     

Luminescent properties of Eu2+and Dy3+ ions in Ba4Al2O7 phosphor for solid state lighting

In this paper we report the combustion synthesis of rare earth (RE=Eu, Dy) doped Ba₄Al₂O₇ phosphors. Prepared phosphors were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), CIE color co-ordinates and their photoluminescence (PL) properties were also investigated. In case of Ba₄Al₂O₇: Eu²⁺, the emission spectra show unique band centered at 495 nm, which corresponds to the 4f⁶5d¹→4f⁷ transition of Eu²⁺, and PL emission spectra of Dy³⁺ ion under 348 nm excitation give two bands centered at 478 nm (blue) and 575 nm (yellow), which originate from the transitions of ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→⁶H_13/2 of Dy³⁺, respectively. The results indicate that the Eu²⁺ and Dy³⁺ activated Ba₄Al₂O₇ phosphor could find application in solid state lighting.     

Electric properties of levels of 156Dy rotational bands

The nonadiabaticity of E0 transitions from 0 ₂ ⁺ states and 2 ₁ ⁺ bands in ¹⁵⁶Dy is examined within a phenomenological model that takes into account the mixing of K ^π = 0 ₁ ⁺ , 0 ₂ ⁺ , 0 ₃ ⁺ , 2 ₁ ⁺ states and 1⁺-bands. It is shown that the nonadiabaticity of E0 transitions is due primarily to the mixing of 0 ₂ ⁺ and 0 ₃ ⁺ bands.     

Properties of rotational excitations in odd mass Dy isotopes

The data on high-spin rotational states in¹⁵⁵Dy,¹⁵⁷Dy,¹⁵⁹Dy and¹⁶¹Dy are discussed within a model where a particle is coupled to a rotor with a variable moment of inertia. In this model there is often a definite improvement in the quality and stability of the fits to levels in the positive-parity band below spin 25/2 when the moment of inertia of the core exhibits a linear dependence on the square of the rotational angular velocity as compared to the situation where a linear dependence onI(I+1) is assumed. In the improved fits the empirical matrix elements of the Coriolis force exhibit a smooth and significant increase with decreasing moment of inertia. The rotational energies above spin 25/2 in the positive-parity band and above 19/2 in the 11/2^? [505] band are understood within the present theoretical model if the moment of inertia increases more rapidly than the linear trend established at lower spin. In the 11/2^? [505] band this increase follows rather closely the behaviour in the even nuclei whereas in the positive-parity band the curves are quite flat even beyond the point where the moment of inertia in the even nuclei exhibits a discontinuous or back-bending behaviour. The significance of this observation is discussed in the light of existing theories on nuclear moments of inertia.     

Magnetospectroscopy of CaF2:Dy2+ in the submillimeter1

The FIR (E₂ → T₂)-like transitions in CaF₂:Dy²⁺ have been observed with both a Fourier transform spectrometer and Submillimeter lasers at magnetic fields of up to 50 kG. Both the 1 → 6 and 2 → 6 transitions exhibit minima of transition energy vs magnetic field. The possibility of utilizing the 2 → 6 transition energy minimum in conjunction with an optically-pumped D₂O laser to produce tunable FIR laser radiation is discussed.     

g-factor measurement of the two lowest 10+ states in 140Sm

The g-factors of the two 10⁺ states in ¹⁴⁰Sm at 3172 and 3210 keV have been measured by means of the TDPAD method. The obtained values are g = −0.176(20) and g = 1.27(9), respectively. The reaction ¹¹⁶Cd (²⁸Si, 4n)¹⁴⁰Sm, at incident beam energy of 125 MeV, has been used. The measured values clearly show that these states can be described as rather pure (νh_11/2)⁻² and (πh_11/2)² configurations.