Lifetime measurements in 138Nd

Lifetimes of the 2_(1)^(+),4_(1)^(+),7_(2)^(-),10_(2)^(+),12_(2)^(+),and 14_(1)^(+) states in 138 Nd populated via the 123 Sb(19 F,4n)138 Nd fusion–evaporation reaction were measured with the recoil distance Doppler shift technique in combination with the differential decay curve method.The B(E2;2_(1)^(+)→0_(1)^(+))value fit well with the systematic trend in the Nd isotope chain and Grodzins rule,which proved that 138Nd is a transitional nucleus.

Lifetime measurement of the 3d^(9) ^(2)D_(3/2) metastable level in Mo^(15+)at an electron beam ion trap

An experimental measurement of the lifetime of 3d^(9) ^(2)D_(3/2) metastable level in Mo^(15+)is reported in this work.The Mo^(15+)ions are produced and trapped in an electron beam ion trap with a magnetic field of 0.65 T.The decay photons emitted from 3d^(9) ^(2)D_(3/2) level are subsequently recorded via a cooled photomultiplier tube.Through meticulous scrutiny of potential systematic uncertainties affecting the measurement outcomes,we have determined the lifetime of Mo^(15+)3d^(9)2D_(3/2)metastable level to be 2.83(22)ms.The experimental result provides a clear distinguishment from existing calculations based on various theoretical approaches.

Precision spectroscopy with a single ^(40)Ca^+ ion in a Paul trap

Precision measurement of the 4s2 S1/2-3d2 D5/2 clock transition based on 40Ca＋ ion at 729 nm is reported. A single 40Ca＋ ion is trapped and laser-cooled in a ring Paul trap, and the storage time for the ion is more than one month. The linewidth of a 729 nm laser is reduced to about 1 Hz by locking to a super cavity for longer than one month uninterruptedly. The overall systematic uncertainty of the clock transition is evaluated to be better than 6.5 ×10^-16. The absolute frequency of the clock transition is measured at the 10^-15 level by using an optical frequency comb referenced to a hydrogen maser which is calibrated to the SI second through the global positioning system （GPS）, The frequency value is 411 042 129 776 393.0（1.6） Hz with the correction of the systematic shifts. In order to carry out the comparison of two 40Ca＋ optical frequency standards, another similar 40Ca＋ optical frequency standard is constructed. Two optical frequency standards exhibit stabilities of 1 × 10^-14 T-1/2 with 3 days of averaging. Moreover, two additional precision measurements based on the single trapped 40Ca＋ ion are carried out. One is the 3d2Ds/2 state lifetime measurement, and our result of 1174（10） ms agrees well with the results reported in [Phys. Rev. A 62 032503 （2000）] and [Phys. Rev. A 71 032504 （2005）]. The other one is magic wavelengths for the 4s2S1/2-3d2Ds/2 clock transition; λ ｜mj｜=1/2= 395.7992（7） nm and λ｜m｜=3/2 = 395.7990（7） nm are reported, and it is the first time that two magic wavelengths for the 40Ca＋ clock-transition have been reported.

Lifetime measurement for the 2^+1 state in^106Cd

The lifetime of the 2^+1 state in ^106Cd populated via the ^94Zr(^16O,4n)^106Cd reaction has been measured with the Recoil Distance Doppler Shift technique in combination with the Differential Decay Curve Method.By subtracting the contamination in the data,the mean lifetime of the I^π=2^+1633 keV state was determined as 9.9(12)ps.The B(E2)value calculated in this study is in good agreement with the experimental systematics and was compared to the shell model calculations.

A Novel Technique of Measuring SOA Differential Carrier Lifetime and a -Factor Using SOA Optical Modulation Response

We demonstrate a new technique of measuring differential carrier lifetime and linewidth enhancement factor in a semiconductor optical amplifier. In our method, the optical responses and fiber transfer functions of a self-gain modulated SOA are measured and, from these, values of carrier lifetimes and linewidth enhancement factors are determined for various SOA input optical powers.

Experimental studies for nuclear chirality in China

In the last decade,chiral symmetry in atomic nuclei has attracted significant attention and become one of the hot topics in current nuclear physics frontiers.This paper provides a review of experimental studies for nuclear chirality in China.In particular,the experimental setups,chiral mass regions,lifetime measurements,and simultaneous breaking of chirality and other symmetries are discussed in detail.These studies found a new chiral mass region(A≈80),extended the boundaries of the A≈100 and 130 chiral mass regions,and tested the chiral geometry of^(130)Cs,^(106)Ag,^(80)Br and^(76)Br by lifetime measurements.In addition,simultaneous breaking of chirality and other symmetries have been studied in^(74)As,^(76)Br,^(78)Br,^(80)Br,^(81)Kr and^(131)Ba.

Dramatic transition between electric and magnetic rotations in ^(106)Ag

The lifetimes for the states of magnetic dipole band in106Ag have been measured using the Doppler-shift attenuation method via the reaction of100Mo(11B,5n)106Ag at a beam energy of 60 MeV.The reduced transition strengths of the magnetic dipole band,the B(M1)/B(E2)ratios together with the signature of the level energy as a function of angular momentum for the positive parity states of106Ag show that a drastic change of excitation mode,that is,from electric rotation to magnetic rotation,occurs within one unit of spin at around Iπ=12+.Theoretical calculations based on the triaxial projected shell model consistently reproduce the experimental data and provide an explanation on the nature of observed phenomena such that the dynamical drift of the rotational axis suddenly from the principal axis to the tilted one,along the positive parity bands of106Ag.

Signature splitting in ^(129)Ce

The high spin states of 129Ce have been populated via heavy-ion fusion evaporation reaction 96Mo (37Cl, 1p3n) 129Ce. The γ-γ coincidence and intensity balance used to measure the B(M1;I →I-1)/B(E2;I → I-2) (the probability ratio of the dipole and quadrupole transition) in ν7/2[523] rotational band of 129Ce. And the energy splitting (△e ’) has been got through the experimental Routhians. The lifetimes and quadrupole moments Qt have been extracted from the lineshape analyses using DSAM. The deformation of the ν7/2[523] rotational band of 129Ce was extracted from the Qt and moment of inertia JRR.