Search results for "Highly charged ion"
showing 10 items of 14 documents
A new 18 GHz room temperature electron cyclotron resonance ion source for highly charged ion beams
2020
An innovative 18 GHz HIISI (Heavy Ion Ion Source Injector) room temperature Electron Cyclotron Resonance (ECR) ion source (ECRIS) has been designed and constructed at the Department of Physics, University of Jyväskylä (JYFL), for the nuclear physics program of the JYFL Accelerator Laboratory. The primary objective of HIISI is to increase the intensities of medium charge states (M/Q ≅ 5) by a factor of 10 in comparison with the JYFL 14 GHz ECRIS and to increase the maximum usable xenon charge state from 35+ to 44+ to serve the space electronics irradiation testing program. HIISI is equipped with a refrigerated permanent magnet hexapole and a noncylindrical plasma chamber to achieve very stro…
The effect of cavity tuning on oxygen beam currents of an A-ECR type 14 GHz electron cyclotron resonance ion source.
2016
The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success. The inherent difficulty in interpretation of the frequency tuning results is that the effects of microwave coupling system and the ca…
Broadband microwave emission spectrum associated with kinetic instabilities in minimum-B ECR plasmas
2017
Plasmas of electron cyclotron resonance ion sources (ECRISs) are prone to kinetic instabilities due to the resonant heating mechanism resulting in anisotropic electron velocity distribution. Frequently observed periodic oscillations of extracted ion beam current in the case of high plasma heating power and/or strong magnetic field have been proven to be caused by cyclotrontype instabilities leading to a notable reduction and temporal variation of highly charged ion production. Thus, investigations of such instabilities and techniques for their suppression have become important topics in ECRIS research. The microwave emission caused by the instabilities contains information on the electron e…
Lifetimes and g-factors of the HFS states in H-like and Li-like bismuth
2018
The LIBELLE experiment performed at the experimental storage ring (ESR) at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, has successfully determined the ground state hyperfine (HFS) splittings in hydrogen-like ($^{209}\rm{Bi}^{82+}$) and lithium-like ($^{209}\rm{Bi}^{80+}$) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. Besides the transition wavelengths the time resolved detection of fluorescence photons following the excitation of the ions by a pulsed laser system also allows to extract lifetimes of the upper HFS levels and g-fac…
The electron cyclotron resonance ion source with arc-shaped coils concept
2012
The main limitation to further improve the performance of ECR ion sources is set by the magnet technology related to the multipole magnet field used for the closed minimum-B structure. The JYFL ion source group has sought different approaches to improve the strength of the minimum-B structure required for the production of highly charged ion beams. It was found out that such a configuration can be realized with arc shaped coils. The first prototype, electron cyclotron resonance ion source with arc-shaped coils (ARC-ECRIS), was constructed and tested at JYFL in 2006. It was confirmed that such an ion source can be used for the production of highly charged ion beams. Regardless of several cos…
How to measure nuclear ground-state properties in simple systems such as 11Li or U91+?
2008
Abstract Atomic spectroscopy yields key information on properties of ground and isomeric states via a determination of the hyperfine structure and isotope shift. In order to deduce precise nuclear moments and charge radii, the electromagnetic fields produced by the electrons at the site of the nucleus must be known with high accuracy. This is presently possible only for simple systems with very few electrons. This contribution describes two scenarios for such experiments: the determination of the charge radius of the neutron-rich isotopes 8,9Li and of the halo nucleus 11Li at the on-line isotope separators at GSI and TRIUMF and the Highly charged Ion TRAP (HITRAP) facility which is under co…
The first results with the new JYFL 14 GHz ECR ion source
2001
Abstract A new 14 GHz ECR ion source has been built for the Accelerator Laboratory in the Department of Physics (JYFL), University of Jyvaskyla. This source belongs to the family of the LBNL AECR-U-based ECR ion sources. The operation during the first four months has shown that the new ion source performs well and is able to produce intensive highly charged ion beams. For example, 145 μA of O7+ ion beam was recorded. The production of iron and boron ion beams was tested using the MIVOC method. The 56Fe11+ ion beam current reached a value of 115 μA. The intensities of 11B3+ and 11B5+ ion beams were 235 and 52 μA, respectively. This iron beam intensity is the second highest and the boron beam…
Fourier transform-ion cyclotron resonance mass spectrometry — A new tool for measuring highly charged ions in an electron beam ion trap
1995
Abstract Fourier transform-ion cyclotron mass spectrometry has been applied to the study of highly charged ions produced and confined in an electron beam ion trap. Measurements of the relative ion abundance of hydrogenlike and bare krypton ions were made and compared to the abundance ratios determined with standard X-ray techniques. Good agreement was found establishing the reliability of the method as a new tool in highly charged ion research.
Three-Body Coulomb Effects in the Direct Coulomb Breakup of 8B into 7Be + p in the Field of a 208Pb Ion
1999
The amplitude for the Coulomb breakup of a light nucleus in the field of a highly charged ion is considered in the framework of the distorted wave approach, with particular emphasis being laid on correctly taking into account the three-body Coulomb interactions in the final state. Numerical calculations have been performed for the double differential cross section for the reaction 208Pb(8B, 7Be p)208Pb. They clearly demonstrate the importance of long-range three-body Coulomb correlations in the astrophysically interesting regime when the ejectiles have the extremely small relative energies.
Theg-factor of highly charged ions
2015
Highly charged ions provide a unique opportunity to test our understanding of atomic properties under extreme conditions: The electric field strength seen by an electron bound to a nucleus at the distance of the Bohr radius ranges from 1010 V/cm in hydrogen to1016 V/cm in hydrogenlike uranium. The theory of quantum electrodynamics (QED) allows for calculation e.g. of binding energies, transition probabilities or magnetic moments. While at low fields QED is tested to very high precision, new, hypothetical nonlinear effects like photon- photon interaction or a violation of Lorentz symmetry may occur in strong fields which then would lead to an extension of the Standard Model. The ultra-high p…