6,449 research outputs found
Characterization of low loss microstrip resonators as a building block for circuit QED in a 3D waveguide
Here we present the microwave characterization of microstrip resonators made
from aluminum and niobium inside a 3D microwave waveguide. In the low
temperature, low power limit internal quality factors of up to one million were
reached. We found a good agreement to models predicting conductive losses and
losses to two level systems for increasing temperature. The setup presented
here is appealing for testing materials and structures, as it is free of wire
bonds and offers a well controlled microwave environment. In combination with
transmon qubits, these resonators serve as a building block for a novel circuit
QED architecture inside a rectangular waveguide
Towards energy-autonomous wake-up receiver using visible light communication
The use of Visible Light Communication (VLC) in wake-up communication systems is a potential energy-efficient and low-cost solution for wireless communication of consumer electronics. In this paper, we go one step further and propose the use of visible light both for wake-up communication and energy harvesting purposes, with the final objective of an energy-autonomous wake-up receiver module. We first present the details and the design criteria of this novel system. We then present the results of evaluation of design criteria such as solar panel and capacitor type choices. To evaluate the performance of the developed wake-up system with energy-autonomous receiver system, we perform realistic indoor scenario tests, analyzing the effect of varying distances, angles, and light intensities as well as the effect of presence of interfering lights.Peer ReviewedPostprint (author's final draft
49Cr: Towards full spectroscopy up to 4 MeV
The nucleus 49Cr has been studied analysing gamma-gamma coincidences in the
reaction 46Ti(alpha,n)49Cr at the bombarding energy of 12 MeV. The level scheme
has been greatly extended at low excitation energy and several new lifetimes
have been determined by means of the Doppler Shift Attenuation Method.
Shell model calculations in the full pf configuration space reproduce well
negative-parity levels. Satisfactory agreement is obtained for positive parity
levels by extending the configuration space to include a nucleon-hole either in
the 1d3/2 or in the 2s1/2 orbitals.
A nearly one-to-one correspondence is found between experimental and
theoretical levels up to an excitation energy of 4 MeV.
Experimental data and shell model calculations are interpreted in terms of
the Nilsson diagram and the particle-rotor model, showing the strongly coupled
nature of the bands in this prolate nucleus. Nine values of K(pi) are proposed
for the levels observed in this experiment.
As a by-result it is shown that the values of the experimental magnetic
moments in 1f7/2 nuclei are well reproduced without quenching the nucleon
g-factors.Comment: 13 pages, 8 figure
coupling determined beyond the chiral limit
Within the conventional QCD sum rules, we calculate the coupling
constant, , beyond the chiral limit using two-point correlation
function with a pion. We consider the Dirac structure, , at
order, which has clear dependence on the PS and PV coupling schemes
for the pion-nucleon interactions. For a consistent treatment of the sum rule,
we include the linear terms in quark mass as they constitute the same chiral
order as . Using the PS coupling scheme for the pion-nucleon
interaction, we obtain , which is very close to the
empirical coupling. This demonstrates that going beyond the chiral
limit is crucial in determining the coupling and the pseudoscalar coupling
scheme is preferable from the QCD point of view.Comment: 8 pages, revtex, some errors are corrected, substantially revise
Accelerating Neoproterozoic research through scientific drilling
No abstract available
The ZEUS Forward Plug Calorimeter with Lead-Scintillator Plates and WLS Fiber Readout
A Forward Plug Calorimeter (FPC) for the ZEUS detector at HERA has been built
as a shashlik lead-scintillator calorimeter with wave length shifter fiber
readout. Before installation it was tested and calibrated using the X5 test
beam facility of the SPS accelerator at CERN. Electron, muon and pion beams in
the momentum range of 10 to 100 GeV/c were used. Results of these measurements
are presented as well as a calibration monitoring system based on a Co
source.Comment: 38 pages (Latex); 26 figures (ps
Experimental setup for camera-based measurements of electrically and optically stimulated luminescence of silicon solar cells and wafers
We report in detail on the luminescence imaging setup developed within the last years in our laboratory. In this setup, the luminescence emission of silicon solar cells or silicon wafers is analyzed quantitatively. Charge carriers are excited electrically (electroluminescence) using a power supply for carrier injection or optically (photoluminescence) using a laser as illumination source. The luminescence emission arising from the radiative recombination of the stimulated charge carriers is measured spatially resolved using a camera. We give details of the various components including cameras, optical filters for electro- and photo-luminescence, the semiconductor laser and the four-quadrant power supply. We compare a silicon charged-coupled device (CCD) camera with a back-illuminated silicon CCD camera comprising an electron multiplier gain and a complementary metal oxide semiconductor indium gallium arsenide camera. For the detection of the luminescence emission of silicon we analyze the dominant noise sources along with the signal-to-noise ratio of all three cameras at different operation conditions. © 2011 American Institute of Physics
Mid-J CO emission from the Orion BN/KL explosive outflow
High spatial resolution low-J 12CO observations have shown that the
wide-angle outflow seen in the Orion BN/KL region correlates with the famous H2
fingers. Recently, high-resolution large-scale mappings of mid- and higher-J CO
emissions have been reported toward the Orion molecular cloud 1 core region
using the APEX telescope. Therefore, it is of interest to investigate this
outflow in the higher-J 12CO emission, which is likely excited by shocks. The
observations were carried out using the dual-color heterodyne array CHAMP+ on
the APEX telescope. The images of the Orion BN/KL region were obtained in the
12CO J=6-5 and J=7-6 transitions with angular resolutions of 8.6 and 7.4
arcsec, respectively. The results show a good agreement between our higher-J
12CO emission and SMA low-J 12CO data, which indicates that this wide-angle
outflow in Orion BN/KL is likely the result of an explosive event that is
related to the runaway objects from a dynamically decayed multiple system. From
our observations, we estimate that the kinetic energy of this explosive outflow
is about 1-2x10^47 erg. In addition, a scenario has been proposed where part of
the outflow is decelerated and absorbed in the cloud to explain the lack of CO
bullets in the southern part of BN/KL, which in turn induces the methanol
masers seen in this region.Comment: 5 pages, 4 figure
CHAMP+ observations of warm gas in M17 SW
Since the main cooling lines of the gas phase are important tracers of the
interstellar medium in Galactic and extragalactic sources, proper and detailed
understanding of their emission, and the ambient conditions of the emitting
gas, is necessary for a robust interpretation of the observations. With high
resolution (7"-9") maps (~3x3 pc^2) of mid-J molecular lines we aim to probe
the physical conditions and spatial distribution of the warm (50 to few hundred
K) and dense gas (n(H_2)>10^5 cm^-3) across the interface region of M17 SW
nebula. We have used the dual color multiple pixel receiver CHAMP+ on APEX
telescope to obtain a 5'.3x4'.7 map of the J=6-5 and J=7-6 transitions of 12CO,
the 13CO J=6-5 line, and the {^3P_2}-{^3P_1} 370 um fine-structure transition
of [C I] in M17 SW. LTE and non-LTE radiative transfer models are used to
constrain the ambient conditions. The warm gas extends up to a distance of ~2.2
pc from the M17 SW ridge. The 13CO J=6-5 and [C I] 370 um lines have a narrower
spatial extent of about 1.3 pc along a strip line at P.A=63 deg. The structure
and distribution of the [C I] {^3P_2}-{^3P_1} 370 um map indicate that its
emission arises from the interclump medium with densities of the order of 10^3
cm^-3. The warmest gas is located along the ridge of the cloud, close to the
ionization front. An LTE approximation indicates that the excitation
temperature of the embedded clumps goes up to ~120 K. The non-LTE model
suggests that the kinetic temperature at four selected positions cannot exceed
230 K in clumps of density n(H_2)~5x10^5 cm^-3, and that the warm T_k>100 K and
dense (n(H_2)>10^4 cm^-3) gas traced by the mid-J 12CO lines represent just
about 2% of the bulk of the molecular gas. The clump volume filling factor
ranges between 0.04 and 0.11 at these positions.Comment: Accepted for publication in Astronomy and Astrophysics, 12 pages, 10
figures, 1 tabl
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