Search results for "Ion cyclotron resonance"
showing 10 items of 96 documents
Phase-Imaging Ion-Cyclotron-Resonance Measurements for Short-Lived Nuclides
2013
A novel approach based on the projection of the Penning-trap ion motion onto a position-sensitive detector opens the door to very accurate mass measurements on the ppb level even for short-lived nuclides with half-lives well below a second. In addition to the accuracy boost, the new method provides a superior resolving power by which low-lying isomeric states with excitation energy on the 10-keV level can be easily separated from the ground state. A measurement of the mass difference of ^{130}Xe and ^{129}Xe has demonstrated the great potential of the new approach.
The interconversion of the radial motional modes of an ion in a Penning trap mass spectrometer by 4n-polar external radio frequency fields (n= 1,2,3,…
2013
In Penning trap mass spectrometry ion masses are determined by measuring the free cyclotron frequency via the resonant conversion of the magnetron into the cyclotron motional mode, induced by the interaction with an external radio-frequency field. With octupolar rf-fields of frequency the mass resolution has been improved by more than an order of magnitude as compared to conventional quadrupolar fields of frequency and with the same pulse duration. This result raises the question what one might expect from using 12-polar rf-fields with frequency or even 16-polar rf-fields with frequency . In this paper the theoretical model for the interconversion of the radial modes by quadrupolar and octu…
Dynamic regimes of cyclotron instability in the afterglow mode of minimum-Belectron cyclotron resonance ion source plasma
2016
The paper is concerned with the dynamic regimes of cyclotron instabilities in non-equilibrium plasma of a minimum-B electron cyclotron resonance ion source operated in pulsed mode. The instability appears in decaying ion source plasma shortly (1–10 ms) after switching off the microwave radiation of the klystron, and manifests itself in the form of powerful pulses of electromagnetic emission associated with precipitation of high-energy electrons along the magnetic field lines. Recently it was shown that this plasma instability causes perturbations of the extracted ion current, which limits the performance of the ion source and generates strong bursts of bremsstrahlung emission. In this artic…
The Mainz Cluster Trap
1999
When cluster ions are stored by electromagnetic forces they are available in the gas phase for extended preparations and investigations. Over the last decade a Penning trap (Ion Cyclotron Resonance) apparatus has been constructed and further developed with respect to metal cluster research at the Institute of Physics at Mainz. It allows to capture and accumulate ion bunches injected from an external cluster source and to manipulate the ions’ motion, i.e. select and center the clusters of interest. The interactions that have been investigated include those with inert and chemically reactive gases, photons and electrons. Multiple mass spectrometric steps such as fragment ion selection can be …
Position-sensitive ion detection in precision Penning trap mass spectrometry
2009
A commercial, position-sensitive ion detector was used for the first time for the time-of-flight ion-cyclotron resonance detection technique in Penning trap mass spectrometry. In this work, the characteristics of the detector and its implementation in a Penning trap mass spectrometer will be presented. In addition, simulations and experimental studies concerning the observation of ions ejected from a Penning trap are described. This will allow for a precise monitoring of the state of ion motion in the trap.
Beam current oscillations driven by cyclotron instabilities in a minimum-Belectron cyclotron resonance ion source plasma
2014
Experimental observation of cyclotron instabilities in a minimum-B confined electron cyclotron resonance ion source plasma is reported. The instabilities are associated with strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic ms-scale oscillation of the extracted beam currents. Such non-linear effects are detrimental for the confinement of highly charged ions due to plasma perturbations at shorter periodic intervals in comparison with their production time. It is shown that the repetition rate of the periodic instabilities in oxygen plasmas increases with increasing magnetic field strength and microwave power and decreases with increasi…
Plasma instability in the afterglow of electron cyclotron resonance discharge sustained in a mirror trap
2012
The work presented in this article is devoted to time-resolved diagnostics of non-linear effects observed during the afterglow plasma decay of a 14 GHz electron cyclotron resonance ion source operated in pulsed mode. Plasma instabilities that cause perturbations of the extracted ion current during the decay were observed and studied. It is shown that these perturbations are associated with precipitation of high energy electrons along the magnetic field lines and strong bursts of bremsstrahlung emission. The effect of ion source settings on the onset of the observed instabilities was investigated. Based on the experimental data and estimated plasma properties, it is assumed that the instabil…
Effect of electron cyclotron resonance ion source frequency tuning on ion beam intensity and quality at Department of Physics, University of Jyväskyl…
2010
Ion beam intensity and quality have a crucial effect on the operation efficiency of the accelerator facilities. This paper presents the investigations on the ion beam intensity and quality after the mass separation performed with the Department of Physics, University of Jyvaskyla 14 GHz electron cyclotron resonance ion source by sweeping the microwave in the 14.05–14.13 GHz range. In many cases a clear variation in the ion beam intensity and quality as a function of the frequency was observed. The effect of frequency tuning increased with the charge state. In addition, clear changes in the beam structure seen with the beam viewer were observed. The results confirmed that frequency tuning ca…
Oscillations of ECR ion source beam current along the beam transport of the JYFL K-130 cyclotron
2013
A versatile measurement system has been developed to study the temporal characteristics of ion beams in millisecond time scale. The system is composed of data acquisition hardware and LabVIEW based measurement and analysis program. The measurement system and ion beam current oscillation results measured with a 14 GHz AECR-U type ion source at University of Jyv"askyl"a, Department of Physics (JYFL), are presented. It is shown that the ion beams exhibit periodic current fluctuations at frequencies from 100 Hz to 1.5 kHz with amplitudes ranging from 1 to 65 percent of the average beam current. It is argued that these oscillations originate from the ion source plasma since their characteristics…
Highly-charged ions in a penning trap: mass measurements, etc.
1991
The use of a Penning trap will start a new generation of precision experiments on highly charged ions. The long storage time of the ions in combination with a controlled confinement in a very small volume will enable accuracies in mass determination better than δm/m = 10-8.