Search results for " Cyclotron"
showing 10 items of 168 documents
FTICR analysis of the magnetic trapping mode of the electron beam ion trap
1996
Abstract An electron beam ion trap is used to produce and confine highly-charged atomic ions in an energetic electron beam (electron trapping mode). After switching off the electron beam the ions remain trapped due to the external magnetic and electric fields. We have investigated the properties of this magnetic trapping mode by use of Fourier transform ion cyclotron resonance mass spectrometry. We found that the number of highly charged ions and the relative species abundance is nearly the same just before and just after turning off the electron beam. The electron trapping mode thus represents an ideal method for filling the trap in situ without the losses associated with transferring the …
Direct Measurement of the Free Cyclotron Frequency of a Single Particle in a Penning Trap
2011
A measurement scheme for the direct determination of the free cyclotron frequency ${\ensuremath{\nu}}_{c}$ of a single particle stored in a Penning trap is described. The method is based on the dressed states of mode coupling. In this novel measurement scheme both radial modes of the single trapped particle are simultaneously coupled to the axial oscillation mode.
Instabilities of an electron cloud in a Penning trap
2003
We have measured the storage instabilities of electrons in a Penning trap at low magnetic fields. These measurements are carried out as a function of the trapping voltage, for different magnetic fields. It is seen that these instabilities occur at the same positions when the trapping voltage is expressed as a percentage of the maximum voltage, given by the stability limit. The characteristic frequencies at which these instabilities occur, obey a relation that is given by n zω z + n +ω + + n -ω - = 0, where ω z, ω + and ω - are the axial, perturbed cyclotron and the magnetron frequencies of the trapped electrons respectively, and the n's are integers. The reason for these instabilities are a…
3D-simulation studies of the modified magnetic multipole structure for an electron cyclotron resonance ion source
2004
Experiments have shown that efficient operation of an electron cyclotron resonance ion source requires that the magnetic field fulfills the so-called scaling laws. In most cases the requirements for the radial magnetic field, i.e. the strength of the magnetic multipole are the most difficult to satisfy. This is due to the fact that the multipole is usually produced from permanent magnets, which makes a value of 1.3 T feasible. One possible solution to increase the multipole field is the so-called Modified MultiPole Structure (JYFL-MMPS). This new idea makes it possible to increase the magnetic field at the places where the plasma flux is in contact with the plasma chamber wall. In this arti…
Ultra-fast intensified frame images from an electron cyclotron resonance hydrogen plasma at 2.45 GHz: some space distributions of visible and monochr…
2014
First results from an ultra-fast frame image acquisition diagnostic coupled to a 2.45 GHz microwave hydrogen discharge are presented. The plasma reactor has been modified to include a transparent doubled shielded quartz window allowing to viewing the full plasma volume. Pictures describing the breakdown process at 1μs exposure time have been obtained for integrated visible light signal, Balmer-alpha, Balmer-beta lines, and Fulcher-band. Several different plasma emission distributions are reported. The distribution depends on the magnetic field configuration, incident microwave power, and neutral gas pressure. peerReviewed
Studies of plasma breakdown and electron heating on a 14 GHz ECR ion source through measurement of plasma bremsstrahlung
2011
Temporal evolution of plasma bremsstrahlung emitted by a 14?GHz electron cyclotron resonance ion source (ECRIS) operated in pulsed mode is presented in the energy range 1.5?400?keV with 100??s resolution. Such a high temporal resolution together with this energy range has never been measured before with an ECRIS. Data are presented as a function of microwave power, neutral gas pressure, magnetic field configuration and seed electron density. The saturation time of the bremsstrahlung count rate is almost independent of the photon energy up to 100?keV and exhibits similar characteristics with the neutral gas balance. The average photon energy during the plasma breakdown is significantly highe…
Theoretical investigations of different excitation modes for Penning trap mass spectrometry
2013
Abstract In Penning trap mass spectrometry the motion of trapped ions is manipulated by external radio-frequency fields. This paper describes a general theoretical framework to classify the various types of excitation of the ion's motional modes, to identify the resonance frequencies, and to find the effective interaction Hamiltonians which are valid in the vicinity of the resonances. Instead of Cartesian or cylindrical coordinates and momenta our theoretical approach uses the complex oscillator amplitudes of the cyclotron, magnetron, and axial oscillators as its basic dynamical variables. Equations of motion are set up, which can be simplified in the vicinity of resonances by the resonatin…
Precision Determination of Cyclotron Frequencies of Free Electrons and Ions
1982
Within the last two decades the electrodynamical storage of electrons and ions developed into an experimental method of great versatility. That this method is now being used in so many different fields of physics and chemistry results primarily from the long storage times which nowadays can be achieved. Under ultrahigh vacuum conditions and in sufficiently strong electromagnetic fields the particles can easily be trapped for hours or even days. This really long storage time offers the possibility of studying reactions of very slow rate to the chemist and of precision measurement of photon-ion interactions to the physicist. The accuracy of photon-ion interaction measurement is finally limite…
The influence of the trapping potential on the attachment of a second electron to stored metal cluster and fullerene anions
2002
Abstract Singly charged anionic clusters are exposed to a bath of simultaneously stored electrons in ion cyclotron resonance (Penning) traps and thus, dianions are produced. The dianion yield is found to be a function of the potential well depth. As an example, the attachment of electrons to size-selected gold cluster anions Au 25 1− from a laser vaporization source has been studied in detail by time-of-flight mass analysis after ejection of all ions from the trap. Furthermore, the investigation is extended to fullerene anions C 70 1− that are produced by laser desorption from a fullerene target in the external source of a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer…
Recent gold cluster studies in a Penning trap
2002
Abstract A progress report is given on the investigation of metal clusters with an ion cyclotron resonance (Penning) trap. The examples are taken from the recent studies on gold clusters. In particular, the monomer and dimer evaporation is monitored as a function of cluster size. For the particular case of Au 7 + this study is expanded to include the energy dependence of the branching ratio. In connection with the sequential decay of Au 8 + the information can be used for a model-free determination of the dissociation energy of Au 8 + . A second line of studies concerns the production, properties and storage behavior of polyanionic gold clusters. Such species have recently been produced by …