Search results for "trap"
showing 10 items of 2144 documents
Broadband light trapping in thin film solar cells with self-organized plasmonic nano-colloids
2015
The intense light scattered from metal nanoparticles sustaining surface plasmons makes them attractive for light trapping in photovoltaic applications. However, a strong resonant response from nanoparticle ensembles can only be obtained if the particles have monodisperse physical properties. Presently, the chemical synthesis of colloidal nanoparticles is the method that produces the highest monodispersion in geometry and material quality, with the added benefits of being low-temperature, low-cost, easily scalable and of allowing control of the surface coverage of the deposited particles. In this paper, novel plasmonic back-reflector structures were developed using spherical gold colloids wi…
Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion.
2015
An open-ring ion trap, also referred to as transparent trap was initially built up to perform $\beta$-$\nu$ correlation experiments with radioactive ions. This trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single $^{40}$Ca$^+$ ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on $^{40}$Ca$^+$ ions, starting from large clouds and reaching single ion sensitivity.…
Efficient and robust photo-ionization loading of beryllium ions
2017
We demonstrate the efficient generation of Be$^+$ ions with a 60 ns and 150 nJ laser pulse near 235 nm for two-step photo-ionization, proven by subsequent counting the number of ions loaded into a linear Paul trap. The bandwidth and power of the laser pulse are chosen in such a way that a first, resonant step fully saturates the entire velocity distribution of beryllium atoms effusing from a thermal oven. The second excitation step is driven by the same light field causing efficient non-resonant ionization. Our ion-loading scheme is more than 15 times more efficient as compared to former pathways using two-photon continuous wave laser excitation.
Trapping of ions from high energy sources into a radiofrequency ion trap
1982
An attempt is described to confine ions, created externally and accelerated to some energy, in an rf quadrupole trap. 4 keV Ba+ ions were stopped on a Ni foil, placed in an aperture of one trap electrode. The Ba then was evaporated from the heated foil and ionized by electron impact. At background pressure of about 10−5 mbar of various light buffer gases (He, H2, N2), the trap was filled once with 105 ions, at a minimum primary ion number of 1010. The storage time was 10 min. From the data obtained the possibility of spectroseopic experiments on rare isotopes, created with accelerators or nuclear reactors, is discussed.
High-resolution microwave spectroscopy on trapped ion clouds
1994
Ion traps are particular usefully devices for precision spectroscopy on ionic ground states in the microwave domain. Although ultimate precision is achieved only with laser-cooled single ions, in many cases the precision obtained using large uncooled clouds of ions is sufficient for many requirements in atomic physics. The stronger signal in this case makes possible experiments on forbidden transitions or on systems with complex spectra and many substates. Recent examples of laser-microwave double resonance spectra on Pb+ and Eu+ are presented along with attempts to laser-cool a large ion cloud in order to reduce uncertainties from the second-order Doppler effect.
Possible Precision Far—Infrared Spectroscopy on Trapped Ions
1990
One of the necessary conditions for very high resolution spectroscopy is the existence of long-living energy levels between which transitions can be induced by tunable electromagnetic radiation. Moreover the observation time of the particles under investigation should be sufficiently long, and perturbing effects like Doppler broadening and collisions should be very small. All this leads to the technique of trapped ion spectroscopy which offers all the required conditions. It uses the confinement of charged particles to a very small volume in space under ultrahigh vacuum conditions either by application of a r.f. voltage and a small additional d.c. bias to an arrangement of three electrodes …
Profiling of traps in SiO2/Al2O3 gate stack by the charge pumping technique
2006
In this paper, we present our results on the distribution and generation of traps in a SiO 2 /A1 2 O 3 transistor. The investigation has been carried out by using charge pumping measurements, both variable voltage and frequency techniques, and constant voltage stress. By increasing the amplitude of the gate pulse we observe an increase of the charge recombined per cycle closely related to the contribution of shallow traps near the SiO 2 /Al 2 O 3 interface. By reducing the pulse frequency we measure an increase in the charge pumping current due to traps located deeper in the Al 2 O 3 . By combining charge pumping and constant voltage stress measurements, we found that the traps are mostly g…
Lifetime and collisional depopulation of the metastable 5D 3/2-state of Yb+
1988
The lifetime and collisional depopulation rates of the metastable 5D 3/2 state of Yb+ have been determined in a radiofrequency ion trap by observation of the fluorescence count rate after ion excitation by a short laser pulse. From measurements using He, N2 and H2 as buffer gases between 10−8 and 10−6 mbar pressure and linear extrapolation to zero pressure we obtain a lifetime of τ=52.15±1.00 ms and rate constants ofR(H2)=(1.02±0.10)×10−9 cm3/s andR(N2)=(1.78±0.19)×10−10 cm3/s. The lifetime is in fair agreement with a calculated value of 74 ms.
Surface Acoustic Wave Sensors for the Detection of Hazardous Compounds in Indoor Air
2017
Presented at the Eurosensors 2017 Conference, Paris, France, 3–6 September 2017.; International audience; In this work, the authors show the capabilities of Surface Acoustic Wave (SAW) devices coupled with various absorbents to probe the properties of gas sensitive materials for the manufacturing of hazardous gas sensors. The great capabilities of cobalt corroles for the trapping of carbon monoxide (CO) were exploited to produce selective sensors. These corroles were deposited on SAW delay lines surfaces and then exposed to carbon monoxide (CO) in standard conditions. Concentrations of a few hundreds of ppb were measured emphasizing the interest of such sensors for the detection of CO. Anot…
The SMILETRAP facility
1995
The SMILETRAP experimental set-up, a Penning trap mass spectrometer for highly charged ions, is described. Capture and observation of cyclotron frequencies of externally produced highly charged ions, rapid interchange of investigated and reference ions and measurements of the rotational kinetic energies are demonstrated. Mass measurements utilizing different charge states and species to verify the consistency of the measurements are presented. A relative uncertainty of about 10−9 is attained in comparisons between highly charged carbon, nitrogen, oxygen, neon and the singly charged hydrogen molecule.