摘要:

This paper presents a survey of recent work in the field of the physics of trapped ions, as an introduction to thisJournal of Modern Opticsspecial issue. The contrasting properties of trapped ion clouds and the single trapped ion are highlighted, together with their application to frequency standards and fundamental measurements.

ISSN:0950-0340    

DOI:10.1080/09500349214550221

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We report the development of a fieldable frequency standard based on199Hg+ions confined in a hybrid r.f./dc linear ion trap. This trap permits storage of large numbers of ions with reduced susceptibility to the second-order Doppler effect caused by the r.f. confining fields. A 160 mHz wide atomic resonance line for the 40·5 GHz clock transition is used to steer the output of a 5 MHz crystal oscillator to obtain a stability of 2 × 10−15for 24 000 s averaging times. For longer averaging intervals, measurements are limited by instabilities in available hydrogen maser frequency standards. Measurements with 37 mHz linewidth for the Hg+clock transition demonstrate that the inherent stability for this frequency standard is at least as good as 1 × 10−15.

ISSN:0950-0340    

DOI:10.1080/09500349214550231

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In a linear r.f. Paul trap, ‘crystallized’ structures of laser-cooled199Hg+ions are observed. The ground-state hyperfine transition at 40·5 GHz is observed in microwave-optical double-resonance spectroscopy. Future prospects are also discussed.

ISSN:0950-0340    

DOI:10.1080/09500349214550241

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The use of a compensated Penning trap to measure an ion's mass relative to some calibration ion is described along with the leading systematic effects which must be considered. In this respect, magnet stability should no longer be a major limitation. This particular spectrometer has recently been used to determinepreliminaryatomic masses of both3H and3He and can be combined to yield a preliminary endpoint energy for the tritium decay (relative to neutral ground states) of 18 588(10) eV.

ISSN:0950-0340    

DOI:10.1080/09500349214550251

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A tandem Penning trap mass spectrometer is used for mass measurement of radioactive isotopes produced at the on-line isotope separator ISOLDE/CERN. The mass is determined directly and with high accuracy by measuring the cyclotron frequency of the stored ions. Measurements were performed on209210211212221222Fr and226230Ra. A resolving power of 5 × 105was used and an accuracy of 1·8 × 10−7has been achieved.

ISSN:0950-0340    

DOI:10.1080/09500349214550261

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Recent developments in the trapping of ions and neutral atoms suggest that significant improvements in the precision of spectroscopic measurements on such systems can be expected. The application of these techniques to trapped antiprotons, positrons and antihydrogen atoms opens up new possibilities for precision tests of the weak equivalence principle (WEP) for antimatter. It is shown that constraints on WEP for positrons and antiprotons may be imposed by comparison of electron and positron, or proton and antiproton cyclotron frequencies, or of transition frequencies in hydrogen and antihydrogen, at the same height in a gravitational potential. The constraints that may be inferred from the results of existing particle-antiparticle cyclotron frequency comparisons are derived, and the improvements which will be possible from future, higher precision experiments are analysed.

ISSN:0950-0340    

DOI:10.1080/09500349214550271

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This paper discusses the one dimensional quantum motion in a Paul trap maintained by a radio frequency potential. The exact Wigner function is constructed. Similarities and differences with the classical motion and with the motion in a purely harmonic trap are discussed. The stable and unstable cases are both treated.

ISSN:0950-0340    

DOI:10.1080/09500349214550281

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Characteristics of single ion motion and mechanisms of trapping ions in the second stability region of a Paul trap are discussed. The mean kinetic energy and mean width of the spatial distribution of an ion cloud in that region are calculated. Similarities and differences of the results between the first and second stability regions are emphasized.

ISSN:0950-0340    

DOI:10.1080/09500349214550291

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A combined trap is a quadrupole trap to which the fields of both the Paul and the Penning traps are applied. In this paper, equations of motion for ions confined in a combined trap are derived from first principles. The equations of motion are shown to give well-understood solutions for the Paul and Penning traps in the appropriate cases before they are solved to yield the axial and radial oscillation frequencies for ions in a combined trap. The dependence of these oscillation frequencies on the applied fields is investigated.

ISSN:0950-0340    

DOI:10.1080/09500349214550301

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The characteristics of laser-cooled Be+ions stored in a Penning trap are reported. Be+ions are cooled by a laser to approximately 300 mK and the cyclotron and axial frequencies of the cooled ions are measured by a laser fluorescence technique. In addition, ion resonances are observed when several kinds of ions are trapped with Be+ions.

ISSN:0950-0340    

DOI:10.1080/09500349214550311

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor