An ion cooler-buncher for high-sensitivity collinear laser spectroscopy at ISOLDE
TL;DR: A gas-filled segmented linear Paul trap has been installed at the focal plane of the high-resolution separator (HRS) at CERN-ISOLDE, which is able to accumulate the ions and release the sample in bunches with a well-defined time structure.
Abstract: A gas-filled segmented linear Paul trap has been installed at the focal plane of the high-resolution separator (HRS) at CERN-ISOLDE. As well as providing beams with a reduced transverse emittance, this device is also able to accumulate the ions and release the sample in bunches with a well-defined time structure. This has recently permitted collinear laser spectroscopy with stable and radioactive bunched beams to be demonstrated at ISOLDE. Surface-ionized 39, 44, 46K and 85Rb beams were accelerated to 30keV, mass separated and injected into the trap for subsequent extraction and delivery to the laser setup. The ions were neutralized in a charge exchange cell and excited with a co-propagating laser. The small ion beam emittance allowed focussing in the ion-laser overlap region, which is essential to achieve the best experimental sensitivity. Fluorescent photons were detected by a photomultiplier tube as a frequency scan was taken. A gate (typically 7-12μs wide) was set on the photomultiplier signal to accept the fluorescent photons within the time window defined by the bunch. Thus, using accumulation times of 100ms, the dominant contribution to background due to continuous laser scattering could be reduced by a factor of up to 4×104 .
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TL;DR: In this article, the authors present a review of the state-of-the-art in high-resolution laser spectroscopy for the study of nuclear shape, size and multipole moments.
217 citations
TL;DR: In this article, the basic principles of laser spectroscopic investigations, Penning-trap and storage-ring mass measurements of short-lived nuclei are summarized and selected physics results are discussed.
Abstract: Atomic physics techniques for the determination of ground-state properties of radioactive isotopes are very sensitive and provide accurate masses, binding energies, Q-values, charge radii, spins and electromagnetic moments. Many fields in nuclear physics benefit from these highly accurate numbers. They give insight into details of the nuclear structure for a better understanding of the underlying effective interactions, provide important input for studies of fundamental symmetries in physics, and help to understand the nucleosynthesis processes that are responsible for the observed chemical abundances in the Universe. Penning-trap and storage-ring mass spectrometry as well as laser spectroscopy of radioactive nuclei have now been used for a long time but significant progress has been achieved in these fields within the last decade. The basic principles of laser spectroscopic investigations, Penning-trap and storage-ring mass measurements of short-lived nuclei are summarized and selected physics results are discussed.
196 citations
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CERN1
TL;DR: The ISOLDE facility has undergone numerous changes over the last 17 years driven by both the physics and technical community with a common goal to improve on beam variety, beam quality and safety as mentioned in this paper.
Abstract: The ISOLDE facility has undergone numerous changes over the last 17 years driven by both the physics and technical community with a common goal to improve on beam variety, beam quality and safety. Improvements have been made in civil engineering and operational equipment while continuing developments aim to ensure operations following a potential increase in primary beam intensity and energy. This paper outlines the principal technical changes incurred at ISOLDE by building on a similar publication of the facility upgrades by Kugler (2000 Hyperfine Interact. 129 23–42). It also provides an insight into future perspectives through a brief summary issues addressed in the HIE-ISOLDE design study Catherall et al (2013 Nucl. Instrum. Methods Phys. Res. B 317 204–207).
143 citations
TL;DR: The field of laser spectroscopy at on-line facilities, with an emphasis on new techniques, is reviewed in this article, where the authors present a summary of experimental data.
Abstract: In the last decade there has been a renaissance in laser spectroscopy at on-line facilities. This has included the introduction of ion traps and the use of laser ion sources to study the hyperfine structure of exotic nuclei far from stability and produce selective enhancement of isomeric beams. In-source spectroscopy has allowed the study of rare isotopes with yields as low as 0.1 atoms per second. In the case of high-resolution spectroscopy, cooling and trapping the ions has dramatically improved the sensitivity. Some elements that were previously inaccessible to laser spectroscopy are now available for study through the technique of in-trap optical pumping. This paper reviews the field of laser spectroscopy at on-line facilities, with an emphasis on new techniques. A summary of experimental data is presented.
129 citations
Max Planck Society1, Heidelberg University2, Katholieke Universiteit Leuven3, CERN4, University of Liverpool5, University of Edinburgh6, University of the West of Scotland7, Sofia University8, Technische Universität Darmstadt9, Bulgarian Academy of Sciences10, Petersburg Nuclear Physics Institute11, University of Manchester12, Technische Universität München13, Spanish National Research Council14, Frankfurt Institute for Advanced Studies15, University of Surrey16, Lund University17, Australian National University18, University of Mainz19, Complutense University of Madrid20, University of Jyväskylä21, University of Helsinki22, Goethe University Frankfurt23, Ludwig Maximilian University of Munich24, Michigan State University25, Chinese Academy of Sciences26, University of York27, Chalmers University of Technology28, University of Groningen29, Daresbury Laboratory30, Beihang University31, University of Warsaw32, University of Cologne33, Aarhus University34, Columbia University35, Lawrence Livermore National Laboratory36, Stockholm University37, Weizmann Institute of Science38, University of Jena39, Helmholtz Institute Jena40, Saitama University41, Dresden University of Technology42
TL;DR: In this article, the authors proposed to install a storage ring at an ISOL-type radioactive beam facility for the first time, which can provide a capability for experiments with stored secondary beams that is unique in the world.
Abstract: We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
109 citations
References
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11 Aug 2001-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: An ion beam cooler and buncher was developed for the manipulation of radioactive ion beams at ISOLDE/CERN as discussed by the authors, where the efficiency was found to exceed 10% in agreement with simulations.
Abstract: An ion beam cooler and buncher has been developed for the manipulation of radioactive ion beams. The gas-filled linear radiofrequency ion trap system is installed at the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. Its purpose is to accumulate the 60-keV continuous ISOLDE ion beam with high efficiency and to convert it into low-energy low-emittance ion pulses. The efficiency was found to exceed 10% in agreement with simulations. A more than 10-fold reduction of the ISOLDE beam emittance can be achieved. The system has been used successfully for first on-line experiments. Its principle, setup and performance will be discussed.
268 citations
11 Aug 2001-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: An ion beam cooler for mass-separated radioactive ion beams has been developed and tested at the IGISOL-type mass separator facility as mentioned in this paper, where an energy spread below 1 eV and transmission efficiency of 60% were measured.
Abstract: An ion beam cooler for mass-separated radioactive ion beams has been developed and tested at the IGISOL-type mass separator facility Technical description and characteristic properties are presented An energy spread below 1 eV and transmission efficiency of 60% were measured
209 citations
TL;DR: In this paper, hyperfine structures and isotope shifts of barium isotopes in the mass range 122-146 have been measured in the atomic transition 6 s 2 1 S 0 →6 s 6 p 1 P 1 (5536 A ), utilizing collinear fast-beam laser spectroscopy at the ISOLDE facility at CERN.
175 citations
TL;DR: In collinear laser measurements the signal-to-noise ratio has been improved by a factor of 2 x 10(4), allowing spectroscopic measurements to be made with ion-beam fluxes of approximately 50 ions s(-1).
Abstract: A new method has been developed for increasing the sensitivity of collinear laser spectroscopy. The method utilizes an ion-trapping technique in which a continuous low-energy ion beam is cooled and accumulated in a linear Paul trap and subsequently released as a short ( $10--20\ensuremath{\mu}\mathrm{s}$) bunch. In collinear laser measurements the signal-to-noise ratio has been improved by a factor of $2\ifmmode\times\else\texttimes\fi{}{10}^{4}$, allowing spectroscopic measurements to be made with ion-beam fluxes of $\ensuremath{\sim}50\mathrm{ions}{\mathrm{s}}^{\ensuremath{-}1}$. The bunching method has been demonstrated in an on-line isotope shift and hyperfine structure measurement on radioactive ${}^{175}\mathrm{Hf}$.
130 citations
TL;DR: In this paper, a detailed inspection of the apparent similarities seen between neighbouring chains in different regions of the nuclear chart is carried out, with an emphasis on the techniques used for rare and radioactive species.
Abstract: Modern techniques of laser spectroscopy enable measurements of optical isotope shifts and hyperfine structures to be extended across long chains of isotopes reaching far from the region of stability. While the hyperfine structure yields precise information on the spin and electromagnetic moments of the nucleus, the isotope shifts are sensitive to small differential changes in size and shape of the nuclear charge distribution. The experimental situation is reviewed, with an emphasis on the techniques used for rare and radioactive species. The status of the experimental data is summarized. Modified King plots are used to make a detailed inspection of the apparent similarities seen between neighbouring chains in different regions of the nuclear chart.
89 citations