In the search of efficient laser resonance ionization schemes and optimal source parameters, offline laser ion source development is of importance for successful online radioactive beam delivery. An ...overview and update on recent TRIUMF’s resonance ionization laser ion sources (TRILIS) offline developments is presented. This includes titanium-sapphire (Ti:Sa) laser development and the investigation of the laser ionization efficiency dependence on source temperature and laser polarization.
Hot cavity resonant ionization laser ion sources (RILIS) provide a multitude of radioactive ion beams with high ionization efficiency and element selective ionization. However, in hot cavity RILIS ...there still remains isobaric contamination in the extracted beam from surface ionized species. An ion guide-laser ion source (IG-LIS) has been implemented at TRIUMF’s isotope separator and accelerator (ISAC) facility that decouples the hot isotope production region from the laser ionization volume. A number of IG-LIS runs have been conducted to provide isobar free radioactive ion beams for experiments. Isobar suppression of up to 10
6
has been achieved, e.g. for Mg, Cd, Ga and other isotopes, IG-LIS however, still suffers from an intensity loss of 50-100× as compared to hot cavity RILIS. The work towards operating the IG-LIS in an optimized fashion and possible design improvements to the operational prototype for efficient and robust (radiation hard) on-line operation and recent SIMION ion optics simulation results as well as the ongoing development status of the IG-LIS are presented.
RAdiation-Detected Resonance Ionization Spectroscopy (RADRIS) is a versatile method for highly sensitive laser spectroscopy studies of the heaviest actinides. Most of these nuclides need to be ...produced at accelerator facilities in fusion-evaporation reactions and are studied immediately after their production and separation from the primary beam due to their short half-lives and low production rates of only a few atoms per second or less. Only recently, the first laser spectroscopic investigation of nobelium (Z=102) was performed by applying the RADRIS technique in a buffer-gas-filled stopping cell at the GSI in Darmstadt, Germany. To expand this technique to other nobelium isotopes and for the search for atomic levels in the heaviest actinide element, lawrencium (Z=103), the sensitivity of the RADRIS setup needed to be further improved. Therefore, a new movable double-detector setup was developed, which enhances the overall efficiency by approximately 65% compared to the previously used single-detector setup. Further development work was performed to enable the study of longer-lived (t1/2>1 h) and shorter-lived nuclides (t1/2<1 s) with the RADRIS method. With a new rotatable multi-detector design, the long-lived isotope 254Fm (t1/2=3.2 h) becomes within reach for laser spectroscopy. Upcoming experiments will also tackle the short-lived isotope 251No (t1/2=0.8 s) by applying a newly implemented short RADRIS measurement cycle.
We present the first results obtained from the S3 Low-Energy Branch, the gas cell setup at SPIRAL2-GANIL, which will be installed behind the S3 spectrometer for atomic and nuclear spectroscopy ...studies of exotic nuclei. The installation is currently being commissioned offline, with the aim to establish optimum conditions for the operation of the radio frequency quadrupole ion guides, mass separation and ion bunching, providing high-efficiency and low-energy spatial spread for the isotopes of interest. Transmission and mass-resolving power measurements are presented for the different components of the S3-LEB setup. In addition, a single-longitudinal-mode, injection-locked, pumped pulsed-titanium–sapphire laser system has been recently implemented and is used for the first proof-of-principle measurements in an offline laser laboratory. Laser spectroscopy measurements of erbium, which is the commissioning case of the S3 spectrometer, are presented using the 4f126s23H6→4f12(3H)6s6p optical transition.
Using TRIUMF's off-line laser ion source test stand with a system of tunable titanium sapphire lasers, the polarization dependence of laser resonance ionization has been investigated using beryllium. ...A significant polarization dependence was observed for the excitation path 1S0 → 1P1∘ → 1S0, which are typical transitions for alkaline-earth and alkaline-earth like elements. This polarization dependence was further verified on Be radioactive isotopes at TRIUMF's isotope separator and accelerator facility (ISAC). Laser polarization was proven to be an important parameter in operating resonance ionization laser ion sources (RILIS).
The polarization spectroscopy was performed off-line both on the 2p2 1S0 autoionizing (AI) state and high-n Rydberg states of the 2sns1S0 and 2snd1D2 series. The energy of the 2p2 1S0 AI state and ionization potential (IP) of beryllium were extracted as 76,167(6) cm−1 and 75,192.59(3) cm−1. Polarization spectroscopy can be used to determine the J values of newly found states in in-source spectroscopy of the complex/radioactive alkaline-earth like elements such as Ra, Sm, Yb, Pu and No.
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•Polarization-dependent laser resonance ionization of Be in hot-cavity ion sources•Polarization spectroscopy on the 2p2 1S0 AI state and 2sns1S0 and 2snd1D2 series•2p2 1S0 autoionizing state energy measured to be 76,167(6) cm−1•Ionization potential of Be measured to be 75,192.59(3) cm−1•Polarization dependence observed for 9–11 Be isotopes in hot-cavity ion sources.
The radiation detection resonance ionization spectroscopy (RADRIS) technique enables laser spectroscopic investigations of the heaviest elements which are produced in atom-at-a-time quantities from ...fusion-evaporation reactions. To achieve a high efficiency, laser spectroscopy is performed in a buffer-gas environment used to thermalize and stop the high-energy evaporation residues behind the velocity filter SHIP. The required cyclic measurement procedure in combination with the applied filament collection for neutralization as well as confinement of the stopped ions and subsequent pulse-heat desorption constrains the applicability of the technique. Here, some of these limitations and also opportunities that arise from this unique measurement setup will be evaluated.
High-resolution laser system for the S3-Low Energy Branch Romans, Jekabs; Ajayakumar, Anjali; Authier, Martial ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
03/2023, Letnik:
536
Journal Article
Recenzirano
In this paper we present the first high-resolution laser spectroscopy results obtained at the GISELE laser laboratory of the GANIL-SPIRAL2 facility, in preparation for the first experiments with the ...S3-Low Energy Branch. Studies of neutron-deficient radioactive isotopes of erbium and tin represent the first physics cases to be studied at S3. The measured isotope-shift and hyperfine structure data are presented for stable isotopes of these elements. The erbium isotopes were studied using the 4f126s23H6→4f12(3H)6s6pJ= 5 atomic transition (415 nm) and the tin isotopes were studied by the 5s25p2(3P0)→5s25p6s(3P1) atomic transition (286.4 nm), and are used as a benchmark of the laser setup. Additionally, the tin isotopes were studied by the 5s25p6s(3P1)→5s25p6p(3P2) atomic transition (811.6 nm), for which new isotope-shift data was obtained and the corresponding field-shift F812 and mass-shift M812 factors are presented.
In-gas-jet laser spectroscopy with S3-LEB Ajayakumar, Anjali; Romans, Jekabs; Authier, Martial ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
June 2023, Letnik:
539
Journal Article
Recenzirano
The Super Separator Spectrometer-Low Energy Branch (S3-LEB) is a low-energy radioactive ion beam experiment under commissioning as part of the GANIL-SPIRAL2 facility. It will be used for the ...production and study of exotic nuclei by in-gas laser ionization and spectroscopy (IGLIS), decay spectroscopy, and mass spectrometry. We report recent results from the off-line commissioning of S3-LEB, including first laser spectroscopy measurements in both the gas cell and the supersonic gas jet, the determination of the transport efficiency of laser ions from the gas cell through the RFQ chain, and time-of-flight measurements with the multi-reflection time-of-flight mass spectrometer PILGRIM. The measurements were performed using erbium, introduced by evaporation from a heated filament in the gas environment. The reported laser spectroscopy results include a characterization of the pressure broadening in the gas cell, proof-of-principle isotope shift measurements, and hyperfine-structure measurements.
High-resolution laser system for the S 3 -Low Energy Branch Romans, Jekabs; Ajayakumar, Anjali; Authier, Martial ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
03/2023, Letnik:
536
Journal Article
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