Search results for "BUFFER GAS"
showing 10 items of 47 documents
The B 1Pi state of NaCs: high resolution laser induced fluorescence spectroscopy and potential construction.
2007
The lowest (1)Pi state of the NaCs molecule, the B(1)(1)Pi state, was studied using a dye laser for inducing fluorescence that was resolved by a high resolution Fourier-transform spectrometer. The presence of argon buffer gas yielded rich rotational relaxation spectra allowing to enlarge the data set for the B(1)(1)Pi state, to obtain Lambda-splittings and to reveal numerous local perturbations. 543 weakly perturbed energy levels for rotational quantum numbers from J(')=5 to 168 and vibrational quantum numbers from v(')=0 to 25, which cover about 87% of the potential well depth, were used for a direct pointwise fit of the potential energy curve applying the inverted perturbation approach me…
Precision Measurement of the First Ionization Potential of Nobelium
2018
One of the most important atomic properties governing an element's chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.626 21±0.000 05 eV. This work provides a stringent benchmark for st…
Production of neutron deficient rare isotope beams at IGISOL; on-line and off-line studies
2004
This article reports on recent on-line yield measurements employing the light-ion and heavy-ion reaction-based ion guide systems and new results on a-recoil ion transport properties in ion guides with and without electric fields. In addition, the presently used ion guide designs for fusion evaporation reactions are introduced. The present study investigated different schemes for ion extraction from the gas cell. The addition of an extra ring electrode between the traditional skimmer electrode and the exit hole led to transmission independent of the primary beam intensity as opposed to strong intensity dependence observed earlier with the plain skimmer only. Furthermore, the mass resolving p…
Fission studies at IGISOL/JYFLTRAP: Simulations of the ion guide for neutron-induced fission and comparison with experimental data
2020
For the production of exotic nuclei at the IGISOL facility, an ion guide for neutron-induced fission has been developed and tested in experiments. Fission fragments are produced inside the ion guide and collected using a helium buffer gas. Meanwhile, a GEANT4 model has been developed to simulate the transportation and stopping of the charged fission products. In a recent measurement of neutron-induced fission yields, implantation foils were located at different positions in the ion guide. The gamma spectra from these foils and the fission targets are compared to the results from the GEANT4 simulation. In order to allow fission yield measurements in the low yield regions, towards the tails a…
Etude des effets cohérents dans la vapeur de rubidium atomique sous irradiation laser bi-chromatique
2013
The effect of electromagnetically induced transparency is observed, using nanocelland microcell. The EIT-resonance with good parameters (high contrast and small FWHM) is obtained in thick cells. The EIT-resonance splitting in magnetic field is observed for the cases of D1-line of 85Rb and 85Rb. The theoretical model, explaining the EIT-resonance components frequency shift dependence on magnetic field strength is presented. The theoretical and experimental results are compared and good agreement is shown. Also the EIT-resonance behavior in hyperfine Paschen-Back regime is presented and explained. For the first time the N-type resonance in microcell is observed. Good parameters of theN-type r…
Study of optical and magneto processes in Rb atomic vapor layer of nanometric thickness
2012
Using a narrow-band resonant fluorescence spectra from a nano-cell with a thickness of L= [lambda]/2, and VSOP resonances formed at a thickness L =[lambda] ([lambda] is the wavelength of the resonant radiation), for the first time it was experimentally investigated the behaviour of the frequency and intensity (transition probabilities) of the atomic hyperfine structure transitions between the 85Rb, 87Rb, D1 and D2 lines Zeeman sublevels in external magnetic fields in range 5 - 7000G. The behaviour of tens of previously unstudied atomic transitions was analyzed and it is demonstrated that the intensities of these lines can both greatly increase, and decrease (tenfold). For the first time it …
Controlling diffusion of 3He by buffer gases: a structural contrast agent in lung MRI.
2006
Purpose: To study the influence of admixing inert buffer gases to laser-polarized 3 He in terms of resulting diffusion coefficients and the consequences for image contrast and resolution. Materials and Methods: The diffusion coefficient of 3 He was altered by admixing buffer gases of various molecular weights ( 4 He, N2, and SF6). The influence of the pulse sequence and the diffusion coefficient on the appearance of MRI of (laserpolarized) gases was analyzed by comparison of basic theoretical concepts with demonstrative experiments. Results: Excellent agreement between theoretical description and observed signal in simple gradient echoes was observed. A maximum signal gain can be predicted …
Time Characteristics of the Ion Beam Cooler-Buncher at JYFL
2001
A beam cooler for low-energy ion beams was constructed to improve the ion optical properties of radioactive ion beams produced at the IGISOL facility in Jyvaskyla. The beam cooler is a buffer gas filled RF-quadrupole. The delay properties and the possibility to accumulate a continuous IGISOL beam and release it in short bunches is discussed.
Essential features of optical processes in neon-buffered submicron-thin Rb vapor cell
2010
A new submicron thin cell (STC) filled with Rb and neon gas is developed and comparison of resonant absorption with STC containing pure Rb is provided. The effect of collapse and revival of Dicke-type narrowing is still observable for the thickness L = lambda /2 and L = lambda , where lambda is a resonant laser wavelength 794 nm (D(1) line). For an ordinary Rb cm-size cell with addition of buffer gas, the velocity selective optical pumping/saturation (VSOP) resonances in saturated absorption spectra are fully suppressed if neon pressure0.5 Torr. A spectacular difference is that for L = lambda , VSOP resonances are still observable even when neon pressure isor = 6 Torr. Narrow fluorescence s…
Study of As and Tl high-frequency electrodeless lamps for Zeeman absorption spectroscopy
2020
High-frequency electrodeless light sources are known as bright radiators with the line spectrum, characterized by high intensities and narrow line shapes. The lamp balloons are mostly made of quartz and filled with a metal and buffer gas. These light sources must be optimized for each application in accordance with the specific requirements of radiation quality, lifetime, and stability. This work is devoted to the diagnostic of high-frequency electrodeless light sources for their use in high precision atomic absorption analyzers and other applications like disinfection. The spectral line intensities and profiles were studied in discharges with arsenic and thallium fillings. Special attentio…