States Of 133Cs Research Articles

Hyperfine coupling constants of the cesium 7D5/2 state measured up to the octupole term.

We report the measurement of hyperfine splitting (HFS) in the 7D5/2 state of 133Cs using high-resolution Doppler-free two-photon spectroscopy enabled by precise frequency scans using an acousto-optic modulator (AOM). All six hyperfine levels are resolved in our spectra. We determine the hyperfine coupling constants A = -1.70867(62) MHz and B = 0.050(14) MHz which represent an over 20-times improvement in the precision of both A and B. Moreover, our measurement is sufficiently precise to put bounds on the value of the magnetic octupole coupling constant C = 0.4(1.4) kHz for the 7D5/2 state. We additionally report the measurement of the ac Stark shift [-46 ± 4 Hz/(W/cm2)], collisional shift, and pressure broadening which are important for optical frequency standards based on the 6S1/2 → 7D5/2 two-photon transition.

Lifetime measurement of the first excited [formula omitted] state in 133Cs using NaI(Tl) and LaBr3(Ce) detectors

We report a new high-precision lifetime measurement of the first excited 5/2+ state of 133Cs using NaI(Tl) and LaBr3(Ce) detectors. The time difference between the coincident decays of two successive states was measured using fast-timing electronics. The 356-keV (1/2+→5/2+) gamma transition was tagged by the successive 81-keV (5/2+→7/2+) transition of 133Cs. The half-life of the first excited 5/2+133Cs state was measured as T1/2=6.283±0.004 (stat.) ±0.011(syst.) ns.

Investigation of high spin states in 133Cs

Investigation of high spin states in 133Cs

Precision measurement of the hyperfine structure of 8d2D3/2 state of 133Cs by the radio-frequency phase modulation technique

We report the measurement of the hyperfine structure in the 8d2D3/2 state of 133Cs isotope by Doppler free two-photon fluorescence spectroscopy in a gas cell. The hyperfine level separations were measured by the radio-frequency phase modulation technique using a frequency stabilized Ti:sapphire laser. The frequency separation between various hyperfine levels of the excited state has been measured with a precision of ~60kHz. From the measured hyperfine separations of the excited state, we have determined the magnetic dipole coupling constant (A) and the electric quadrupole coupling constant (B) for the 8d2D3/2 state. The determined hyperfine structure constants are A=3.98 (0.01) MHz and B=−0.03 (0.09) MHz. Our deduced magnetic dipole coupling constant (A) value is thus by far the most precise and was found to be in good agreement with the 3σ level with the earlier reported values. This work reports the electric quadrupole coupling constant (B) value for the 8d2D3/2 state for the first time.

On the decay of the Jπ = 11/2−, T1/2 = 38.9 h isomer in 133Ba: search for the E5 transition and verification of the EC branch

This paper presents a search for the competing 11/2− → 1/2+ E5 branch to the main 11/2− → 3/2+ M4 transition from the T1/2 = 39 h, Jπ = 11/2− isomeric state in 133Ba. An upper limit of 1.8 × 10−5 could be established for the E5/M4 intensity ratio. In addition, a longstanding controversy in the EC decay of the same isomer was resolved: only one EC branch to the 11/2+ state in 133Cs was observed. The shell-model structures of the involved states in 133Ba and 133Cs were studied with the microscopic quasiparticle-phonon model. Good agreement with the decay rates B(λ) was obtained. In particular, the B(M4) value is well reproduced and further only one low-lying 11/2 state could be identified in the latter nuclide, supporting the experimental results.

A Novel Digital Pulse-Shape Analysis for High-Resolution Position-Sensitive Gamma-Ray Spectroscopy

A novel digital pulse-shape analysis (DPSA) was performed for high-resolution position-sensitive gamma-ray spectroscopy with coaxial-type high-purity germanium (HpGe) detectors. The DPSA consisted of two stages that determined the pulse height, the interaction point and the start time by using the chi-square fitting the digitally recorded pulse shapes with calculated shapes. As the DPSA was applied to gamma-ray spectroscopy using HpGe coaxial detectors, we obtained the energy spectra, the time-difference spectra and the interaction depth profiles for the gamma rays emitted from 133Ba and 22Na standard sources. The efficiency of the spectroscopic analysis using the DPSA was compared with that using a conventional analog signal process (CASP). Furthermore, we determined the half-lifetime of the first excited state in 133Cs by using the DPSA.

Level-crossing spectroscopy of the 7, 9, and10D5∕2states ofCs133and validation of relativistic many-body calculations of the polarizabilities and hyperfine constants

We present an experimental and theoretical investigation of the polarizabilities and hyperfine constants of D_J states in 133Cs for J=3/2 and J=5/2. New experimental values for the hyperfine constant A are obtained from level-crossing signals of the (7,9,10)D_5/2 states of 133Cs and precise calculations of the tensor polarizabilities alpha_2. The results of relativistic many-body calculations for scalar and tensor polarizabilities of the (5-10)D_3/2 and (5-10)D_5/2 states are presented and compared with measured values from the literature. Calculated values of the hyperfine constants A for these states are also presented and checked for consistency with experimental values.

Precise measurement of hyperfine structure in the 6P1/2 state of 133Cs

We have measured hyperfine structure in the 6P1/2 state of 133Cs using a frequency-stabilized diode laser and acousto-optic modulators that produce calibrated frequency offsets. We check for errors due to radiation-pressure and optical-pumping effects by repeating the measurements at different values of pump power in a saturated-absorption spectrometer. We obtain a precise value of the magnetic-dipole constant, A = 291.9135(15) MHz, representing an improvement of more than an order of magnitude.

Delayed coincidence technique for 133gXe detection

Delayed coincidence techniques show promise of significant improvements for a Xe counting system which will be a key element in monitoring the Comprehensive Test Ban Treaty. We have previously developed a beta–gamma counting system for 131mXe, 133mXe, 133gXe, and 135gXe as part of an automated system for analyzing Xe in air. Depending on background levels, higher sensitivity for 133gXe can be achieved by use of the delayed coincidence between beta particles that feed the 81 keV state in 133Cs and the conversion electrons produced in the deexcitation of the 81 keV state ( t 1/2=6.36 ns). In the delay time region, only the 31 keV X-ray associated with 133gXe decay is observed. This technique detects 133gXe with extremely low background and distinguishes 133gXe from 131mXe and 133mXe.

Manipulation of level-crossing signals using narrow-band or pulsed laser excitation

Level-crossing experiments yielding Doppler-free signals are normally performed using a CW light source with a broad spectral distribution ("white" excitation), and the signals obtained are described by a well-known formula due to Breit. By using a single-mode dye laser or a pulsed laser for the excitation, strong modifications of level-crossing signals can be obtained. Profound changes in hyperfine structure crossing signals are demonstrated in experiments, performed in a cell, on the 9 2D3/2 state of 133Cs. Practical utilisation of unconventional excitation in level-crossing and optical double resonance spectroscopy is discussed.

Coulomb excitation of 133Cs with protons

Protons of energy 3.2–4.2 MeV have been used to Coulomb excite the states in 133Cs. The thick-target gamma-ray yields and the angular distributions were measured using a 50 cm3 Ge(Li) detector. The measurements were used to extract the reduced transition probabilities, B (E2) and B(M1), and multipole mixing ratios (δ) for the various transitions. A spin assignment has been made to the 871.8 keV level on the basis of angular distribution data. The results obtained have been compared with those of other authors.

Hyperfine structures, lifetimes and collisional cross sections of some Rydberg D states of133Cs

Earlier experimental work on the n2D3/2 states of 133Cs has been extended to n=15 and 16. Hyperfine interaction constants and radiative lifetimes are found to follow the trends established for lower values of n, but the measured collisional cross sections are smaller than the extrapolated values.

Nuclear magnetic moment of the 161 keV state and other spectroscopic investigations of 133Cs

The magnetic moment of the 161 keV state of 133 Cs was remeasured by the 1PAC technique in an external magnetic field of 9.5 T as μ I(161keV) = 2.0(2)n.m. The known half-life of the 161 keV state, T 1/2 = 190(15)ps, was confirmed by a Coulomb-excitation experiment. The 161 keV state as well as the few other states for which large B(E2)↑ values are observed exhibit the characteristic properties of a ground state core-excitation multiplet as proposed by de-Shalit. A high precision remeasurement of the 276 keV–161 keV γ-γ angular correlation by use of a three Ge(Li) detector system gave A 2 = −0.495(5) and A 4 = −0.54(6), and confirms the result obtained by Winn and Sarantites which is in contradiction to all previous data. A comparison of the M1/E2 mixing ratio derived from this angular correlation for the 161 keV transition with recent precise data for the total conversion coefficient proves that anomalous conversion is present and leads to the penetration parameter λ = +25(9).

Two quantum-beat phenomena observed for magnetically tuned atomic sublevels

Quantum-beat signals can also be observed when the length of the exciting pulse is not short compared to the Bohr precession period if spontaneous decays during the pulse are important. Experimental demonstration for Zeeman quantum beats in the 6s6p 3P 1−6s 2 1S 0 ytterbium transition, as well as a simple description of the phenomenon is given. In the same way as quantum beats can be obtained for coherently excited Zeeman sublevels close to the zero-field level crossing, beats can be induced close to a high-field level crossing. We have observed such high-field quantum beats for the 7 2P 3 2 state of 133Cs.

The sign and magnitude of the quadrupole interaction of the 81 keV state of133Cs and 247 keV state of111Cd in Te

The sign and magnitude of the quadrupole interaction of the 81 keV state of133Cs and 247 keV state of111Cd in Te

Lifetimes, depopulation cross sections and hyperfine structures of some Rydberg S and D states of133Cs

Measurements have been made of time-resolved fluorescence from n2S1/2 and n2D3/2 states of 133Cs (n=8 to 14) over a range of vapour densities covering the onset of collisional depopulation. Lifetimes for the free atom and depopulation cross sections are deduced. Lifetimes are proportional to (n*)x with x=2.52+or-0.06 (S states) and 2.62+or-0.06 (D3/2 states). Cross sections are proportional to (n*)4. Hyperfine-structure interaction constants for the 2D3/2 states determined by the method of quantum beats agree with the recent results of Belin et al. (1976).

Hyperfine Interaction, Zeeman and Stark Effects for Excited States in Cesium

Our previous measurements in the P and D series in 133Cs have been extended to a number of higher lying levels, populated in a two-step excitation process involving an rf lamp and a CW dye laser. The D states were studied with the level-crossing technique, while the optical-double-resonance method was used for the investigation of the P states. For the magnetic dipole interaction constant a, the Landé gJ factor, and the tensor polarizability α2 we obtain12 2P3/2: a = 1.10(3) MHz, gJ = 1.3340(15)13 2P3/2: a = 0.77(5) MHz, gJ = 1.3337(20)7 2D3/2: |a| = 7.4(2) MHz14 2D3/2: |a| = 0.425(7) MHz15 2D3/2: |a| = 0.325(8) MHz16 2D3/2: |a| = 0.255(12) MHz17 2D3/2: |a| = 0.190(12) MHz18 2D3/2: |a| = 0.160(10) MHz13 2D5/2: α2 = 19(1) GHz/(kV/cm)214 2D5/2: α2 = 37(2) GHz/(kV/cm)215 2D5/2: α2 = 70(4) GHz/(kV/cm)216 2D5/2: α2 = 120(6) GHz/(kV/cm)217 2D5/2: α2 = 199(10) GHz/(kV/cm)218 2D5/2: α2 = 323(16) GHz/(kV/cm)2Ab initio calculations of many-body perturbation type, including polarization effects to all orders, have been performed in order to obtain theoretical values of the hyperfine structure constants. The resulting a factors are listed together with the corresponding experimental values for most S, P, and D states in 133Cs measured so far. The discrepancy between the experimental and theoretical values is mainly due to the omission of the correlation effect, which is essentially as important as the polarization effect. Still, for the D states the polarization effect is large enough to yield negative values for all the 2D5/2 states, which is in accordance with the experimental results. Semiempirical values of the a factors have also been obtained using the Fermi-Segré-Goudsmit formula, and the results are compared with the experimental values. The measured values of α2 agree well with values calculated with the Coulomb approximation due to Bates and Damgaard.

Investigation of the scalar stark interaction for excited S and D levels in cesium using high resolution laser spectroscopy

The scalar polarizability constant α 0 for the 10, 11 2S 1 2 and 9 2D 5 2 states of 133Cs was measured i Stark effect experiment on a collimated atomic beam. The states were reached by a two-step excitation procedure involving a single-mode dye laser.

GJ-factors and magnetic hfs interaction constants in the [formula omitted]- and [formula omitted]-states of 133Cs

The hyperfine structures in the 6 2P 3 2 -and 8 2P 3 2 -states of 133Cs have been investigated by optical double resonance in a strong magnetic field. For the g J -factors and the magnetic hfs coupling constants we obtain: g J(6 2 P 3 2 ) = 1.3340 (3), a (6 2 P 3 2 ) = 50.02(25) MHz, g J(8 2 P 3 2 ) = 1.3342(2), a (8 2 P 3 2 ) = 7.644(25) MHz .

Determination of the gJ-factor and the magnetic hfs interaction constant in the -state of 133Cs by optical double resonance in a strong magnetic field

Abstract The hyperfine structure of the 6 2 P 1 2 -state of 133Cs has been measured by optical double resonance in a strong magnetic field. The magnetic hfs coupling constant and the gJ-factor were found to be: a 1 2 = 291.90(12) MHz ; gj = 0.66590(9).