Search results for "Ground"

Precise determination of the ground state hyperfine structure splitting of43Ca II

1994

We have performed a laser microwave double resonance experiment on43Ca+ ions stored in a Paul ion trap. The ground state hfs splitting has been determined to Δν=3 225 608 286. 4(3) Hz. The value is corrected for small Zeeman, Stark and second order Doppler shifts as well as for light shift effects caused by the laserfields. The uncertainty is mainly determined by the errors of these corrections.

Experimental ground stateg J-factor of Ba+ in a Penning ion trap

1993

We observed the Zeeman-splitting of the 6S1/2 – 6P1/2 resonance transition of Ba+-ions (493.4 nm) in a 6T magnetic field. The ions were stored in a Penning quadrupole trap. We polarized the ground state by optical pumping and in a microwave-optical double resonance experiment we measured the ground state Zeeman-splitting. From the resonance frequency and the cyclotron frequency of electrons stored in the same trap we derived theg-factor of the 6S1/2 state. The result isgJ(6S1/2)=2.002 490 6(11), in reasonable agreement with recent calculations.

2nu3 band of 12CF4 and its simultaneous analysis with nu3

1995

Abstract A nearly Doppler-limited spectrum of the 2ν 3 band of the 12 CF 4 molecule between 2536.0 and 2599.8 cm −1 was recorded at T = 77 K using difference-frequency laser spectroscopy. The simultaneous analysis of the ground (G.S.), ν 3 = 1, and ν 3 = 2 states was performed using an isolated band model to sixth order in the tetrahedral formalism. Fourteen hundred seventy-five transitions were assigned through J = 35 to the F 2 and E vibrational components of the ν 3 = 2 level. A total of 1864 transition frequencies were fit simultaneously (1000 2ν 3 - G.S. newly assigned transitions together with 575 ν 3 - G.S. and 289 ν 3 - ν 3 transitions already reported in the literature). The ground…

Development of a TES based Cryo-Anticoincidence for a large array of microcalorimeters

2009

The employment of large arrays of microcalorimeters in space missions (IXO, EDGE/XENIA)[1][2][3], requires the presence of an anticoincidence detector to remove the background due to the particles, with a rejection efficiency at least equal to Suzaku (98%) [1]. A new concept of anticoincidence is under development to match the very tight thermal requirements and to simplify the design of the electronic chain. The idea is to produce a Cryo-AntiCoincidence (Cryo-AC) based on a silicon absorber and read by a TES (Transition-Edge Sensor). This configuration would ensure very good performances in terms of efficiency, time response and signal to noise ratio. We present the results of estimations,…

Cascade coherence transfer and magneto-optical resonances at 455 nm excitation of Cesium

2010

We present and experimental and theoretical study of nonlinear magneto-optical resonances observed in the fluorescence to the ground state from the 7P_{3/2} state of cesium, which was populated directly by laser radiation at 455 nm, and from the 6P_{1/2} and 6P_{3/2} states, which were populated via cascade transitions that started from the 7P_{3/2} state and passed through various intermediate states. The laser-induced fluorescence (LIF) was observed as the magnetic field was scanned through zero. Signals were recorded for the two orthogonal, linearly polarized components of the LIF. We compared the measured signals with the results of calculations from a model that was based on the optica…

Phase joint transform sequential correlator for nonlinear binary correlations

2005

We study the performance of nonlinear optical correlations using a joint transform correlator that operates in phase-only spatial light modulation at input joint transform plane. Amplitude input nonlinear optical time sequential correlations have shown better discrimination and noise robustness than conventional linear correlations. Those nonlinear correlations are based on decomposing the reference and the target into binary slices and to add the contribution of all linear correlations between them. Those correlations can be easily implemented using a conventional joint transform correlator. However, the system has poor efficiency and low cross-correlation peak intensity, mainly because of…

Preliminary assessment of the ATHENA/WFI non-X-ray background

2017

We present a preliminary assessment of the non-X-ray background for the WFI on board ATHENA conducted at IAAT in the context of the collaborative background and radiation damage working group activities. Our main result is that in the baseline configuration originally assumed for the camera the requirement on the level of non-X-ray background could not be met. In light of the results of Geant4 simulations we propose and discuss a possible optimization of the camera design and pinpoint some open issues to be addressed in the next phase of investigation. One of these concerns the possible contribution to the non-X-ray background from soft protons and ions funneled to the focal plane through t…

First Observation of Atomic Levels for the Element Fermium (Z=100)

2003

The atomic level structure of the element fermium was investigated for the first time using a sample of $2.7\ifmmode\times\else\texttimes\fi{}{10}^{10}$ atoms of the isotope $^{255}\mathrm{F}\mathrm{m}$ with a half-life of 20.1 h. The atoms were evaporated from a filament and stored in the argon buffer gas of an optical cell. Atomic levels were sought by the method of resonance ionization spectroscopy using an excimer-dye-laser combination. Two atomic levels were found at wave numbers $(25\text{ }099.8\ifmmode\pm\else\textpm\fi{}0.2)$ and $(25\text{ }111.8\ifmmode\pm\else\textpm\fi{}0.2)\text{ }\text{ }{\mathrm{c}\mathrm{m}}^{\ensuremath{-}1}$. Partial transition rates to the $5{f}^{12}7{s}…

Excitation transfer between the rubidium52Dfine-structure levels in collisions with ground-state rubidium atoms: Experiment and theory

2000

Determination of the first ionization potential of technetium

2010

Using resonance ionization spectroscopy the first-ionization potential of actinium has been determined by analyzing different Rydberg series in two-color resonant laser excitation. Three individual Rydberg series were investigated, converging toward the ionic ground state and toward the first- and second-excited state of the actinium ion, respectively. A combined analysis of the convergence limits leads to a consistent value for the first-ionization potential of Ac of $43\phantom{\rule{0.16em}{0ex}}394.45\phantom{\rule{0.16em}{0ex}}(19)\phantom{\rule{0.28em}{0ex}}{\text{cm}}^{\ensuremath{-}1}$, equivalent to $5.380\phantom{\rule{0.16em}{0ex}}226\phantom{\rule{0.16em}{0ex}}(24)$ eV.