Single-ion cyclotron resonance measurement ofM(CO+)/M(N2+

Abstract

We have trapped single molecular ions in a precision Penning trap and, using cyclotron resonance techniques, have measured the mass ratio M(CO + )/M(N2 + ) to be 0.999 598 8876(4). Accuracy is limited at 4xl0~1 0 predominantly by temporal instability in the magnetic field. All other systematic sources of error are AM/M^S 10 ~1 0 . PACS numbers: 35.10.Bg, 07.75.+hThe Penning trap, with its strong uniform magnetic field and its much weaker electric field, has been used to perform a number of very accurate quantitative experiments. 1-4 We have used a Penning trap for mass spectroscopy using single-ion cyclotron resonance (SICR). The absence of ion-ion interaction makes systematics easy to understand; hence SICR is the most accurate method of comparing mass. The AM/M-4x 10 ~1 0 result reported here, limited predominantly by the temporal drift in the magnetic field, is a factor of 6 better than the value from current tables, 5 and may be the most accurate ion mass comparison to date.A hyperbolic Penning trap 6 consists of three main electrodes, all hyperbolic surfaces of rotation, which provide a restoring electric field which is linear with displacement along the axis of rotation. The much stronger axial magnetic field confines the particle radially. For a single charged particle there are three normal modes, one (the "axial" mode) that is aligned with the magnetic field, and two perpendicular to it. The perpendicular ("radial") modes are the electric field-modified cyclotron motion at frequency v' c and the slower magnetron orbit, due basically toExB drift.The ratio of the cyclotron frequencies for two different ion species, when corrected for electric field effects, is simply the inverse of their mass ratio. Our approach, then, is to compare the cyclotron frequencies of alternately loaded single ions. For an M -28 amu ion, the cyclotron, axial, and magnetron frequencies in our trap are, respectively, v^4.5 MHz, v z = 160 kHz, and v m ^2.8 kHz.Our trap hangs vertically in the bore of an 8.5-T superconducting Oxford magnet. The magnet has superconducting shims and a custom Dewar in the bore which allows us to cycle the trap from room temperature to 4.2 K while keeping the magnet itself cold. The main electrodes are precision-machined oxygen-free high-conductivity copper, plated with gold and coated with a layer of graphite particles (Aquadag) to minimize surface patch effects. The three main electrodes are spaced by machinable ceramic (MACOR) rings on which are painted guard ring electrodes, used to shim out higher-

Determination of the direct double-β-decayQvalue ofZr96and atomic masses ofGulyuz1, Ariche2, Bollen3 et al. 2015Phys. Rev. C

“…PTMS has become a very important tool in mass measurements of atomic nuclei due to the high precision and accuracy that it provides [5][6][7]. In this paper, we present the first direct measurement of the 96 Zr double-β decay Q value using PTMS.…”

ISOLTRAP: An on-line Penning trap for mass spectrometry on short-lived nuclides

“…Since this can only be achieved within certain limits, it is still important to construct the trap such that the inhomogeneity is smaller than the aimed mass accuracy. Magnetic-field instability is another point of concern and is determined by the magnet itself, ambient magneticfield changes, pressure changes in the helium cryostat, and temperature changes of the experimental equipment installed in the magnet bore [49][50][51][52]. The demand for the magnetic-field stability is defined by the desired mass accuracy and by the switching time between the cyclotron frequency measurements of the reference ion and the ion of interest.…”

Highly sensitive superconducting circuits at ∼700 kHz with tunable quality factors for image-current detection of single trapped antiprotons

“…To achieve high frequency resolution in noisedip based measurements, small ∆ν z and inherently weak particle-detector interaction is favorable, while peak detection requires strong particle-detector coupling [23]. To adjust the detector to the requirements of the respectively applied method, we developed a superconducting switch which allows continuous and sensitive tuning of R eff .…”