Search results for "Laser ionization"

Observation of two-XUV-photon ionization using harmonic generation from a short, intense laser pulse

1996

We report the observation of a two-photon ionization process in the XUV wavelength regime. In a near-resonant 1 + 1 ionization scheme, Ar atoms are ionized absorbing the 15 eV third harmonic photons produced in a gas jet by the 0.5 ps intense laser pulses of a KrF excimer laser emitting at 248.6 nm. The present demonstration of a non-linear process in the XUV regime reveals feasibility of high-intensity applications utilizing the uniquely high peak power of non-conventional short wavelength radiation sources based on harmonic generation.

Three-photon resonance ionization of atomic Mn in a hot-cavity laser ion source using Ti:sapphire lasers

2015

Three-photon resonance ionization of atomic manganese (Mn) in a hot-cavity ion source using Ti:sapphire lasers has been demonstrated. Three-step ionization schemes employing different intermediate levels and Rydberg or autoionizing (AI) states in the final ionization step are established. Strong AI resonances were observed via the 3d54s5s f 6S5/2 level at 49 415.35 cm−1, while Rydberg transitions were reached from the 3d54s4d e 6D9/2,7/2,5/2 levels at around 47 210 cm−1. Analyses of the strong Rydberg transitions associated with the 3d54s4d e 6D7/2 lower level indicate that they belong to the dipole-allowed 4d → nf 6F°9/2,7/2,5/2 series converging to the 3d54s 7S3 ground state of Mn II. Fro…

Resonant laser ionization of polonium at rilis-isolde for the study of ground- and isomer-state properties

2008

Three new ionization schemes for polonium have been tested with the resonant ionization laser ion source (RILIS) during the on-line production of 196Po in a UCx target at ISOLDE. The saturation of the atomic transitions has been observed and the yields of the isotope chain 193–198,200,202,204Po have been measured. This development provides the necessary groundwork for performing in-source resonant ionization spectroscopy on the neutron-deficient polonium isotopes (Z = 84). ispartof: Nuclear Instruments & Methods in Physics Research B vol:266 issue:19 pages:4403-4406 ispartof: location:FRANCE, Deauville status: published

Developments for resonance ionization laser spectroscopy of the heaviest elements at SHIP

2016

Abstract The experimental determination of atomic levels and the first ionization potential of the heaviest elements ( Z ⩾ 100 ) is key to challenge theoretical predictions and to reveal changes in the atomic shell structure. These elements are only artificially produced in complete-fusion evaporation reactions at on-line facilities such as the GSI in Darmstadt at a rate of, at most, a few atoms per second. Hence, highly sensitive spectroscopic methods are required. Laser spectroscopy is one of the most powerful and valuable tools to investigate atomic properties. In combination with a buffer-gas filled stopping cell, the Radiation Detected Resonance Ionization Spectroscopy (RADRIS) techniq…

Absolute cross-sections for the nonresonant multi-photon ionization of toluene and xylene in the gas phase

2001

Abstract The absolute multi-photon ionization cross-section of the phenyl ring was determined by laser-ionization of toluene and xylene molecules in the gas phase. Excitation was achieved using nonresonant four-photon absorption of the frequency doubled light of a 10 ns pulsed Nd:YAG laser (532 nm). The resulting ions were stored in a Penning trap and detected by time-of-flight mass spectrometry. The values of the cross-sections are 1.4(3)×10 −42 cm 8 W −4 s −1 and 1.3(3)×10 −42 cm 8 W −4 s −1 for toluene and xylene, respectively.

Efficient, high-resolution resonance laser ionization spectroscopy using weak transitions to long-lived excited states

2017

Laser spectroscopic studies on minute samples of exotic radioactive nuclei require very efficient experimental techniques. In addition, high resolving powers are required to allow extraction of nuclear structure information. Here we demonstrate that by using weak atomic transitions, resonance laser ionization spectroscopy is achieved with the required high efficiency (1%–10%) and precision (linewidths of tens of MHz). We illustrate experimentally and through the use of simulations how the narrow experimental linewidths are achieved and how distorted resonance ionization spectroscopy line shapes can be avoided. The role of the delay of the ionization laser pulse with respect to the excitatio…

Trace Analysis of Plutonium and Technetium by Resonance Ionization Mass Spectrometry Using an Atomic Beam and a Laser Ion Source

1990

A method for low level detection of plutonium and technetium is described with a detection limit of less than 107 atoms. Plutonium is a very toxic element due to its radioactive decay as well as its chemical behaviour. It was released to the environment in large amounts during the fifties and sixties of his century, principally by nuclear-weapon tests and some accidents. As a result about 0.4 − 4 mBq per gram 239Pu(T1/2 = 24390 y), corresponding to 4 × 108 − 4 × 109 atoms, can be found in the Northern Hemisphere in soil samples.

Gas-phase chemistry, recoil source characterization and in-gas-cell resonance laser ionization of actinides at IGISOL

2018

The underlying theme of this thesis focuses on buffer gas purification and relevant gas-phase ion chemistry which critically affects ion beam purity at gas cell-based radioactive ion beam facilities. The achievement of attaining a sub- parts-per-billion level of impurity at the IGISOL facility has enabled subsequent gas cell developments for production of the actinide elements, plutonium and thorium, required for a program of high-resolution optical spectroscopy. Firstly, the construction and characterization of the new IGISOL buffer gas purification system is presented. Off-line ion beam production of plutonium and thorium using in-gas-cell laser resonance ionization combined with filament dispen…

Studies of resonant laser ionization of yttrium atoms in helium

2007

Realization of time-resolved two-vacuum-ultraviolet-photon ionization

2009

International audience; Ultrafast dynamics of excited molecules is studied through time-resolved two-vacuum-ultraviolet (vuv)- photon ionization using a nonlinear volume autocorrelator unit. The two-vuv-photon process is induced by the intense fifth harmonic radiation of a femtosecond Ti:sapphire laser. In a proof-of-principle experiment, ultrafast dynamics of excited ethylene and oxygen molecules are investigated. Molecular decay times are deduced by comparing the experimental data with the results of a numerical model that accounts for the spatial and temporal characteristics of the harmonic field. The present experiments pave a convenient way for time domain investigations in the vuv-xuv s…