528 research outputs found
Deceleration and electrostatic trapping of OH radicals
A pulsed beam of ground state OH radicals is slowed down using a Stark
decelerator and is subsequently loaded into an electrostatic trap.
Characterization of the molecular beam production, deceleration and trap
loading process is performed via laser induced fluorescence detection inside
the quadrupole trap. Depending on details of the trap loading sequence,
typically OH () radicals are trapped at a density
of around cm and at temperatures in the 50-500 mK range. The 1/e
trap lifetime is around 1.0 second.Comment: 4 pages, 3 figure
Loading Stark-decelerated molecules into electrostatic quadrupole traps
Beams of neutral polar molecules in a low-field seeking quantum state can be
slowed down using a Stark decelerator, and can subsequently be loaded and
confined in electrostatic quadrupole traps. The efficiency of the trap loading
process is determined by the ability to couple the decelerated packet of
molecules into the trap without loss of molecules and without heating. We
discuss the inherent difficulties to obtain ideal trap loading, and describe
and compare different trap loading strategies. A new "split-endcap" quadrupole
trap design is presented that enables improved trap loading efficiencies. This
is experimentally verified by comparing the trapping of OH radicals using the
conventional and the new quadrupole trap designs
Direct measurement of the radiative lifetime of vibrationally excited OH radicals
Neutral molecules, isolated in the gas-phase, can be prepared in a long-lived
excited state and stored in a trap. The long observation time afforded by the
trap can then be exploited to measure the radiative lifetime of this state by
monitoring the temporal decay of the population in the trap. This method is
demonstrated here and used to benchmark the Einstein -coefficients in the
Meinel system of OH. A pulsed beam of vibrationally excited OH radicals is
Stark decelerated and loaded into an electrostatic quadrupole trap. The
radiative lifetime of the upper -doublet component of the level is determined as ms, in good
agreement with the calculated value of ms.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
Development of a fast laser ablation-inductively coupled plasma-mass spectrometry cell for sub-”m scanning of layered materials
Performance data are reported for a commercially available laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) setup, equipped with a custom-made cell. The low dispersion ablation cell and the connecting tubing achieve a 99% washout of the aerosol in similar to 6 ms, enabling separated pulse responses at frequencies up to 200-300 Hz. In addition, the cell employed supports a post-acquisition methodology for the deconvolution of overlapping ablation positions in scanning mode by an iterative Richardson-Lucy algorithm. This enables correction of the distortion in the scan profile upon traversing layers with dimensions below the physical size of the laser beam. By overlapping the ablation positions of a 1 mu m diameter laser beam, a lateral resolution in the order of 0.3 +/- 0.1 mu m was demonstrated for scanning of mu m-sized layers in high capacitance multi-layer ceramic capacitors
Combination of a fast ablation cell and deconvolution approaches for high resolution LA-ICP-MS scanning of layered materials
Fast high resolution 2D and 3D laser ablation-inductively coupled plasma-mass spectrometry imaging via deconvolution approaches and ablation cell design
Integrable and superintegrable systems associated with multi-sums of products
We construct and study certain Liouville integrable, superintegrable, and
non-commutative integrable systems, which are associated with multi-sums of
products.Comment: 26 pages, submitted to Proceedings of the royal society
Strong-coupling effects in the relaxation dynamics of ultracold neutral plasmas
We describe a hybrid molecular dynamics approach for the description of
ultracold neutral plasmas, based on an adiabatic treatment of the electron gas
and a full molecular dynamics simulation of the ions, which allows us to follow
the long-time evolution of the plasma including the effect of the strongly
coupled ion motion. The plasma shows a rather complex relaxation behavior,
connected with temporal as well as spatial oscillations of the ion temperature.
Furthermore, additional laser cooling of the ions during the plasma evolution
drastically modifies the expansion dynamics, so that crystallization of the ion
component can occur in this nonequilibrium system, leading to lattice-like
structures or even long-range order resulting in concentric shells
- âŠ