Search results for "Cyclotron"
showing 10 items of 320 documents
Experimental ground stateg J-factor of Ba+ in a Penning ion trap
1993
We observed the Zeeman-splitting of the 6S1/2 – 6P1/2 resonance transition of Ba+-ions (493.4 nm) in a 6T magnetic field. The ions were stored in a Penning quadrupole trap. We polarized the ground state by optical pumping and in a microwave-optical double resonance experiment we measured the ground state Zeeman-splitting. From the resonance frequency and the cyclotron frequency of electrons stored in the same trap we derived theg-factor of the 6S1/2 state. The result isgJ(6S1/2)=2.002 490 6(11), in reasonable agreement with recent calculations.
A new plasma potential measurement instrument for plasma ion sources
2004
A very efficient and fast instrument to measure the plasma potential of ion sources has been developed at the Department of Physics, University of Jyvaskyla (JYFL). The operating principle of this novel instrument is to apply a decelerating voltage into a mesh located in the beamline of the ion source. The plasma potential is determined by measuring the current at the grounded electrode situated behind the mesh as a function of the voltage. In this article, we will introduce the instrument and the first results. In the experiments, the instrument was connected to the beamline of the JYFL 6.4 GHz electron cyclotron resonance ion source. The plasma potential was measured with different source…
Precise $\sf g_J$ - and $\sf g_I$ -factor measurements of Ba + isotopes
1998
Laser-microwave double and triple resonance experiments were performed on clouds of Ba+ ions confined in a Penning ion trap to induce and detect electronic and nuclear spin flip transitions. Collisions with buffer gas molecules in the trap was used to reduce the lifetime of a long lived metastable state of the ions, in which population trapping might occur, and to cool the ions to the ambient temperature. Loss of ions from the trap by collisions were prevented by coupling the magnetron and reduced cyclotron motions by an additional r.f. field at the sum frequency of the two motions. Electronic Zeeman transitions in 138Ba+ and 135Ba+ were observed at a full width of about 3 kHz at a transiti…
Competition of fission with the population of the yrast superdeformed band in $^{194}$Pb
1999
The 194Pb yrast superdeformed band has been populated in two reactions induced by two different beams delivered by the JYFL cyclotron. These two reactions differ in the asymmetry ratio (i.e. the ratio of the target mass over the projectile one) by more than a factor 3. For the first time, a superdeformed band of the A≈190 mass region has been populated using such a very heavy beam, namely 74Ge.
g-factor measurement of hydrogenlike28Si13+as a challenge to QED calculations
2013
Using a phase-detection method to determine the cyclotron frequency of a single trapped ion in a Penning trap allowed us to perform a measurement of the $g$ factor of the bound electron in hydrogenlike ${}^{28}$Si${}^{13+}$ with a statistical uncertainty of $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$. Furthermore, we reevaluated the image-charge shift as the main source of uncertainty. Our result challenges bound-state quantum-electrodynamical calculations by probing two-loop contributions of order (Z$\ensuremath{\alpha}$)${}^{6}$ and paves the way towards a more precise determination of fundamental constants as the electron mass.
Analysis of equations arising in gyrotron theory
2012
The gyrotron is a microwave source whose operation is based on the stimulated cyclotron radiation of electrons oscillating in a static magnetic field. Powerful gyrotrons can be used to heat nuclear fusion plasma. In addition, they have found a wide utility in plasma diagnostics, plasma chemistry, radars, extra-high-resolution spectroscopy, high-temperature processing of materials, medicine, etc. However, the main application of gyrotrons is in electron cyclotron resonance heating in tokamaks and stellarators. Equations describing gyrotron operation are ordinary differential equations and Schrödinger type partial differential equations. The present paper provides a survey of the analytical a…
Image charge shift in high-precision Penning traps
2019
An ion in a Penning trap induces image charges on the surfaces of the trap electrodes. These induced image charges are used to detect the ion's motional frequencies, but they also create an additional electric field, which shifts the free-space cyclotron frequency typically at a relative level of several ${10}^{\ensuremath{-}11}$. In various high-precision Penning-trap experiments, systematics and their uncertainties are dominated by this so-called image charge shift (ICS). The ICS is investigated in this work by a finite-element simulation and by a dedicated measurement technique. Theoretical and experimental results are in excellent agreement. The measurement is using singly stored ions a…
High-frequency Ramsey excitation in a Penning trap
2007
The Ramsey excitation method for high-precision mass-measurements of highly-charged ions has been investigated and benchmarked using H2+ ions in the Penning-trap mass-spectrometer SMILETRAP. The reason for using H2+ ions are their high cyclotron frequency which is typical for the highly-charged ions usually used at SMILETRAP. Two-, three- and four-pulse Ramsey excitation data are analyzed with the help of recent theoretical work and are compared with the previously used single-pulse excitation data. An improvement factor of 2.9 in the statistical uncertainty is achieved. Furthermore the mass of 76Se, included in the previous Q-value measurement of the 76Ge neutrinoless double beta decay, is…
JYFLTRAP: a Penning trap for precision mass spectroscopy and isobaric purification
2012
In this article a comprehensive description and performance of the double Penning-trap setup JYFLTRAP will be detailed. The setup is designed for atomic mass measurements of both radioactive and stable ions and additionally serves as a very high-resolution mass separator. The setup is coupled to the IGISOL facility at the accelerator laboratory of the University of Jyväskylä. The trap has been online since 2003 and it was shut down in the summer of 2010 for relocation to the upgraded IGISOL facility. Numerous atomic mass and decay energy measurements have been performed using the time-of-flight ion-cyclotron resonance technique. The trap has also been used in several decay spectroscopy expe…
The $\mathsf{g_{\scriptscriptstyle J}}$ -factor in the ground state of Ca $^\mathsf{+}$
2003
We have determined the $g_{\scriptscriptstyle J}$ -factor of the Ca + ion in the electronic 4S1/2 ground state on a cloud of ions confined in a Penning trap with a superimposed magnetic field of 1.43 T. We use a c.w. laser to prepare a Zeeman substate by optical pumping and induce $\Delta m_J=1$ transitions by a resonant microwave field at 40 GHz. Resonance is detected by a change in the fluorescence intensity originating from the ion cloud. We obtain a full width in the resonance of a few kHz and the fractional uncertainty of the line center, taking the average of several measurements, was 4 x 10-8. After calibrating the magnetic field by the cyclotron frequency of electrons stored in the …