Search results for "Rapping"
showing 10 items of 280 documents
Production, trapping, and detection of ultracold polar KPb molecules
2005
Corrigendum: Fabrication and heating rate study of microscopic surface electrode ion traps
2012
We report heating rate measurements in a microfabricated goldon-sapphire surface electrode ion trap with a trapping height of approximately 240 μm. Using the Doppler recooling method, we characterize the trap heating rates over an extended region of the trap. The noise spectral density of the trap falls in the range of noise spectra reported in ion traps at room temperature. We find that during the first months of operation, the heating rates increase by approximately one order of magnitude. The increase in heating rates is largest in the ion-loading region of the trap, providing a strong hint that surface contamination plays a major role for excessive heating rates. We discuss data found i…
High-frequency vibrational density of states of a disordered solid.
2013
We investigate the high-frequency behavior of the density of vibrational states in three-dimensional elasticity theory with spatially fluctuating elastic moduli. At frequencies well above the mobility edge, instanton solutions yield an exponentially decaying density of states. The instanton solutions describe excitations, which become localized due to the disorder-induced fluctuations, which lower the sound velocity in a finite region compared to its average value. The exponentially decaying density of states (known in electronic systems as the Lifshitz tail) is governed by the statistics of a fluctuating-elasticity landscape, capable of trapping the vibrational excitations.
Counting IndividualCa41Atoms with a Magneto-Optical Trap
2004
Atom trap trace analysis, a novel method based upon laser trapping and cooling, is used to count individual atoms of $^{41}\mathrm{Ca}$ present in biomedical samples with isotopic abundance levels between ${10}^{\ensuremath{-}8}$ and ${10}^{\ensuremath{-}10}$. The method is calibrated against resonance ionization mass spectrometry, demonstrating good agreement between the two methods. The present system has a counting efficiency of $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$. Within 1 h of observation time, its $3\mathrm{\text{\ensuremath{-}}}\ensuremath{\sigma}$ detection limit on the isotopic abundance of $^{41}\mathrm{Ca}$ reaches $4.5\ifmmode\times\else\texttimes\fi{}{10…
Time-dependent electric field in Al/CdTe/Pt detectors
2015
Abstract Al/CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopy, even though they suffer from bias-induced time instability (polarization). Polarization phenomena cause a progressive time-degradation of the spectroscopic performance of the detectors, due to hole trapping and detrapping from deep acceptor levels that directly control the electric field distribution. In this work we present experimental investigations on the electric field profile of planar Al/CdTe/Pt detectors by means of Pockels effect measurements. The time/temperature dependence of the electric field was investigated in a long time window (up to 10 h) and the correlation with the reverse c…
Anomalous behavior of LiF:Mg,Cu,P (TLD100H) irradiated with electron beams
2006
Abstract Thermoluminescent dosimeters of LiF:Mg,Cu,P (TLD100H) were exposed to 60Co γ -ray, protons, high energy electrons and the glow curves were analyzed. We observed an unusual behavior of the TL response of dosimeters to 7 and 14 MeV electron beam. In fact the relative amplitude between two of the five peaks (2° and 3° peaks) assumes values smaller than the unity for doses up to 5 Gy and values greater than the unity for doses equal to or greater than 10 Gy. A possible explanation of this behavior is given adopting a model of the formation of the peaks 2° and 3° and examining the different ways of energy release in matter for each beam. To perform this analysis we deconvoluted the glow…
Precise determination of the ground state hyperfine splitting of135Ba+
1983
A microwave-optical double resonance experiment has been performed on135Ba+ ions, confined in a r.f. quadrupole trap. Linewidths as narrow as 0.9 Hz have been obtained on the 7.18 GHz,F=1,m=0 toF=2,m=0 transition. Shifts of the resonance frequency due to magnetic stray fields and the electric trapping field have been observed. The final result, extrapolated to zero field strengths, isΔ υHFS=7183340234.90(0.57) Hz.
Production and trapping of carbon clusters for absolute mass measurements at ISOLTRAP
2001
Singly-charged carbon clusters C/sub n//sup +/ (n >or= 1) have been produced by laser-induced desorption and fragmentation of C/sub 60/ fullerenes and have been injected into and stored in the Penning trap system of the ISOLTRAP mass spectrometer at ISOLDE/CERN. The present study is the first step to extend the until now direct mass measurements at ISOLTRAP to absolute mass measurements by using clusters of /sup 12/C. (10 refs).
Deceleration of antiprotons from MeV to keV energies
1993
Trapping of antiprotons for high precision measurements at the Low Energy Antiproton Ring (LEAR/CERN) requires the deceleration of the antiproton beam from typically 5.8 MeV energy down to 10 keV for final capture in standard Penning traps. Two methods, the degradation of the beam in thin foils and the deceleration of the beam in an inverse cyclotron are investigated so far. The foil technique was successfully demonstrated with trapping efficiencies up to a few 10−4 and is now routinely used in the high precision measurement of the antiprotonproton mass ratio. The degradation foil method is compared with the deceleration technique using an inverse cyclotron tested also at LEAR.
Density and geometry of single component plasmas
2007
Abstract The density and geometry of p ¯ and e + plasmas in realistic trapping potentials are required to understand and optimize antihydrogen ( H ¯ ) formation. An aperture method and a quadrupole oscillation frequency method for characterizing such plasmas are compared for the first time, using electrons in a cylindrical Penning trap. Both methods are used in a way that makes it unnecessary to assume that the plasmas are spheroidal, and it is shown that they are not. Good agreement between the two methods illustrates the possibility to accurately determine plasma densities and geometries within non-idealized, realistic trapping potentials.