Search results for "Penn"

Mass Measurement on therp-Process Waiting PointKr72

2004

With the aim of improving nucleosynthesis calculations, we performed for the first time, a direct high-precision mass measurement on the waiting point in the astrophysical rp-process 72Kr. We used the ISOLTRAP Penning trap mass spectrometer located at ISOLDE/CERN. The measurement yielded a relative mass uncertainty of δm/m = 1.2×10-7. In addition, the masses of 73Kr and 74Kr were measured directly with relative mass uncertainties of 1.0×10-7 and 3×10-8, respectively. We analyzed the role of 72Kr in the rp-process during X-ray bursts using the ISOLTRAP and previous mass values of 72-74Kr.

Mass measurements on unstable Sn and Sr isotopes with the ISOLTRAP mass spectrometer

2001

Direct mass measurements have been performed on the isotopes 76,77,80,81Sr and 129,130,131,132Sn by means of the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. In the case of 76Sr the mass was measured for the first time and an accuracy of about 30 keV was reached (Fig. 1). The masses of the tin isotopes are known for a long time from Q β measurements.

The REX-ISOLDE project

2002

REX-ISOLDE is a pilot experiment at ISOLDE/CERN to study the structure of neutron-rich nuclei (N=20, N=28) with post-accelerated radioactive ion beams (1). Therefore radioactive ions with charge state 1+, which are delivered by the online mass separator ISOLDE, are accelerated up to 2.2 MeV/u by means of a new concept. The radioactive ions are first accumulated in a Penning trap, then charge breeded to a charge-to-mass ratio of 1/4.5 in an Electron Beam Ion Source (EBIS) and finally accelerated. The LINAC consists of three components, namely a Radio Frequency Quadrupole (RFQ) accelerator, which accelerates the ions from 5 to 300 keV/u, an interdigital H-type structure (IH) with a final ener…

First Capture of Antiprotons in an Ion Trap: Progress Toward a Precision Mass Measurement and Antihydrogen

1988

Antiprotons from the Low Energy Antiproton Ring of CERN are slowed from 21 MeV to below 3 keV by being passed through 3 mm of material, mostly Be. While still in flight, the kilo-electron volt antiprotons are captured in a Penning trap created by the sudden application of a 3-kV potential. Antiprotons are held for 100 s and more. Prospects are now excellent for much longer trapping times under better vacuum conditions. This demonstrates the feasibility of a greatly improved measurement of the inertial mass of the antiproton and opens the way to other intriguing experiments. The possibility of producing antihydrogen by merging cold, trapped plasmas of positrons and antiprotons is discussed.

Towards a "perfect" Penning trap mass spectrometer for unstable isotopes

1992

A Penning trap mass spectrometer has been set up at the on-line isotope separator ISOLDE/CERN for the mass determination of unstable heavy isotopes. The spectrometer should fulfil the following requirements: capture of external ions in high efficiency, high resolving power and accuracy, general applicability to all elements and isotopes available at the on-line facility.

2012

A new apparatus has been designed that aims at a direct precision measurement of the g-factor of a single isolated proton or antiproton in a Penning trap. We present a thorough discussion on the trap design and a method for the experimental trap optimization using a single stored proton. A first attempt at the g-factor determination has been made in a section of the trap with a magnetic bottle. The Larmor frequency of the proton has been measured with a relative uncertainty of 1.8◊10 6 and the magnetic moment has been determined with a relative uncertainty of 8.9◊10 6 . Ag-factor of 5.585696(50) has been obtained, which is in excellent agreement with previous measurements and predictions. F…

Double Penning trap technique for precise g factor determinations in highly charged ions

2003

We present a detailed description of an experiment to determine the magnetic moment of an electron bound in hydrogen-like carbon. This forms a high-accuracy test of bound-state quantum electrodynamics. Special emphasis is given to the discussion of systematic uncertainties which limit our present accuracy. The described experimental setup may also be used for the determination of g factors in other highly charged ions.

High-accuracy measurement of the magnetic moment anomaly of the electron bound in hydrogenlike carbon.

2000

We present a new experimental value for the magnetic moment of the electron bound in hydrogenlike carbon (12C5+): g(exp) = 2.001 041 596 (5). This is the most precise determination of an atomic g(J) factor so far. The experiment was carried out on a single 12C5+ ion stored in a Penning trap. The high accuracy was made possible by spatially separating the induction of spin flips and the analysis of the spin direction. The current theoretical value amounts to g(th) = 2.001 041 591 (7). Together experiment and theory test the bound-state QED contributions to the g(J) factor of a bound electron to a precision of 1%.

Highly charged ions, quantum-electrodynamics, and the electron mass

2006

Abstract High precision experiments on the magnetic moment of hydrogen-like ions confined in a Penning trap have provided the most stringent test of bound-state quantum-electrodynamic calculations. Experiments have been performed on single C 5+ and O 7+ ions. These experiments are briefly reviewed and prospects for future improvements and extension to other systems are discussed.

Electrong-factor determinations in Penning traps

2013

The magnetic moment of the electron, expressed by the g-factor in units of the Bohr magneton, is a key quantity in the theory of quantum electrodynamics (QED). Experiments using single particles confined in Penning traps have provided very precise values of the g-factor for the free electron as well as the electron bound in hydrogen-like ions. In this paper the status of these experiments is reviewed. The results allow testing calculations of higher order Feynman diagrams. Comparison of experimental and theoretical results for free and bound particles show no discrepancy within the limits of error, thus representing to date the most sensitive test of QED. Moreover, the g-factor provides a u…