336 research outputs found
Programmable Trigger Logic Unit Based on FPGA Technology
A programmable trigger logic module (TRILOMO) was implemented successfully in
an FPGA using their internal look-up tables to save Boolean functions. Up to 16
trigger input signals can be combined logically for a fast trigger decision.
The new feature is that the trigger decision is VME register based. The changes
are made without modifying the FPGA code. Additionally the module has an
excellent signal delay adjustment.Comment: 4 pages, 4 figure
Differential Scattering Cross-Sections for the Different Product Vibrational States in the Ion-Molecule Reaction Ar+ + N2
The charge transfer reaction Ar+ + N2 --> Ar + N2+ has been investigated in a
crossed beam experiment in combination with three-dimensional velocity map
imaging. Angular differential state-to-state cross sections were determined as
a function of the collision energy. We found that scattering into the first
excited vibrational level dominates as expected, but only for scattering in the
forward direction. Higher vibrational excitations up to v'=6 have been observed
for larger scattering angles. For decreasing collision energy, scattering into
higher scattering angles becomes increasingly important for all kinematically
allowed quantum states. Our detailed measurements indicate that a quantitative
agreement between experiment and theory for this basic ion-molecule reaction
now comes within reach.Comment: accepted to Phys. Rev. Let
Strongly aligned and oriented molecular samples at a kHz repetition rate
We demonstrate strong adiabatic laser alignment and mixed-field orientation
at kHz repetition rates. We observe degrees of alignment as large as
cos\Theta=0.94 at 1 kHz operation for iodobenzene. The experimental setup
consist of a kHz laser system simultaneously producing pulses of 30 fs (1.3 mJ)
and 450 ps (9 mJ). A cold 1 K state-selected molecular beam is produced at the
same rate by appropriate operation of an Even-Lavie valve. Quantum state
selection has been obtained using an electrostatic deflector. A camera and data
acquisition system records and analyzes the images on a single-shot basis. The
system is capable of producing, controlling (translation and rotation) and
analyzing cold molecular beams at kHz repetition rates and is, therefore,
ideally suited for the recording of ultrafast dynamics in so-called "molecular
movies".Comment: 6 pages, 4 figures, in press in Mol. Phys., accepted in February
2013, in final production (galley proofs done) since March 8, 2013, v3 only
adds publication dat
Photodetachment of cold OH- in a multipole ion trap
The absolute photodetachment cross section of OH- anions at a rotational and
translational temperature of 170K is determined by measuring the
detachment-induced decay rate of the anions in a multipole radio-frequency ion
trap. In comparison with previous results, the obtained cross section shows the
importance of the initial rotational state distribution. Using a tomography
scan of the photodetachment laser through the trapped ion cloud, the derived
cross section is model-independent and thus features a small systematic
uncertainty. The tomography also yields the column density of the OH- anions in
the 22-pole ion trap in good agreement with the expected trapping potential of
a large field free region bound by steep potential walls.Comment: Phys. Rev. Lett., in pres
Two-state wave packet for strong field-free molecular orientation
We demonstrate strong laser-field-free orientation of absolute-ground-state
carbonyl sulfide molecules. The molecules are oriented by the combination of a
485-ps-long non-resonant laser pulse and a weak static electric field. The
edges of the laser pulse create a coherent superposition of two rotational
states resulting in revivals of strong transient molecular orientation after
the laser pulse. The experimentally attained degree of orientation of 0.6
corresponds to the theoretical maximum for mixing of the two states. Switching
off the dc field would provide the same orientation completely field-free
Strongly driven quantum pendulum of the OCS molecule
We demonstrate and analyze a strongly driven quantum pendulum in the angular
motion of stateselected and laser aligned OCS molecules. Raman-couplings during
the rising edge of a 50-picosecond laser pulse create a wave packet of pendular
states, which propagates in the confining potential formed by the
polarizability interaction between the molecule and the laser field. This
wave-packet dynamics manifests itself as pronounced oscillations in the degree
of alignment with a laser-intensity dependent period.Comment: 6 pages, 4 figure
Evaporation of buffer gas-thermalized anions out of a multipole rf ion trap
We identify plain evaporation of ions as the fundamental loss mechanism out
of a multipole ion trap. Using thermalized negative Cl- ions we find that the
evaporative loss rate is proportional to a Boltzmann factor. This thermodynamic
description sheds new light on the dynamics of particles in time-varying
confining potentials. It specifically allows us to extract the effective depth
of the ion trap as the activation energy for evaporation. As a function of the
rf amplitude we find two distinct regimes related to the stability of motion of
the trapped ions. For low amplitudes the entire trap allows for stable motion
and the trap depth increases with the rf field. For larger rf amplitudes,
however, rapid energy transfer from the field to the ion motion can occur at
large trap radii, which leads to a reduction of the effective trapping volume.
In this regime the trap depth decreases again with increasing rf amplitude. We
give an analytical parameterization of the trap depth for various multipole
traps that allows predictions of the most favorable trapping conditions.Comment: Phys. Rev. Lett., in pres
Fundamentos del diseno e industrializacion de muebles de linea plana.
159 p.Las posibilidades de un país maderero, como lo es Chile, de incrementar sustancialmente sus
exportaciones en el rubro muebles, están claramente demostradas en estudios comparativos
realizados en otros países exportadores, por ejemplo, Taiwán, país importador de madera,
exporta más de 2000 millones de dólares anuales. (INFOR, 2004)
A nivel nacional, en los últimos años la industria manufacturera de muebles ha tenido un
gran auge de exportaciones; este crecimiento ha generado necesidades inmediatas, entre las
cuales se ha podido detectar: Falta de personal capacitado a nivel de trabajadores y
profesionales, falta de diseños propios, problemas de calidad, tecnologías atrasadas, etc.
(INFOR, 2004)
La demanda por muebles continuará aumentando: El país sólo podrá hacer frente a esta
demanda en la medida que tenga personal capacitado, una red de productores; pequeños,
medianos y grandes, pueda ofrecer diseños, que siendo propios tengan acogida en el mercado
internacional, además de un sistema de Calidad para la fabricación de muebles, donde se
realicen cabalmente las uniones y se escoja apropiadamente los herrajes de acuerdo al diseño de éstos.
La memoria desarrollada pretende en lo fundamental capacitar, transfiriendo al sector
productivo, información sobre diseños, sistemas constructivos adecuados para el mercado
interno y de exportación y el uso de maquinarias. De acuerdo a lo anterior esta memoria está destinada a la descripción de los principales aspectos del funcionamiento y el uso de maquinaria, sistemas de herrajes y diseño de muebles de línea plana; esto se consiguió
adaptando experiencias extranjeras en general, a la realidad nacional, mediante bibliografía
obtenida a través de medios digitales, como también por revisiones bibliográficas
How can a 22-pole ion trap exhibit 10 local minima in the effective potential?
The column density distribution of trapped OH ions in a 22-pole ion trap
is measured for different trap parameters. The density is obtained from
position-dependent photodetachment rate measurements. Overall, agreement is
found with the effective potential of an ideal 22-pole. However, in addition we
observe 10 distinct minima in the trapping potential, which indicate a breaking
of the 22-fold symmetry. Numerical simulations show that a displacement of a
subset of the radiofrequency electrodes can serve as an explanation for this
symmetry breaking
Improved spatial separation of neutral molecules
We have developed and experimentally demonstrated an improved electrostatic
deflector for the spatial separation of molecules according to their
dipole-moment-to-mass ratio. The device features a very open structure that
allows for significantly stronger electric fields as well as for stronger
deflection without molecules crashing into the device itself. We have
demonstrated its performance using the prototypical OCS molecule and we discuss
opportunities regarding improved quantum-state-selectivity for complex
molecules and the deflection of unpolar molecules.Comment: 6 figure
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