13,000 research outputs found
An Electro - Optical Test System for Optimising Operating Conditions of CCD sensors for LSST
We describe the commissioning of a system which has been built to investigate
optimal operation of CCDs for the LSST telescope. The test system is designed
for low vibration, high stability operation and is capable of illuminating a
detector in flat-field, projected spot, projected pattern and Fe-55
configurations. We compare and describe some considerations when choosing a
gain calibration method for CCDs which exhibit the brighter-fatter effect. An
optimisation study on a prototype device of gain and full well with varying
back substrate bias and gate clock levels is presented
Characterizing the Quantum Confined Stark Effect in Semiconductor Quantum Dots and Nanorods for Single-Molecule Electrophysiology
We optimized the performance of quantum confined Stark effect QCSE based
voltage nanosensors. A high throughput approach for single particle QCSE
characterization was developed and utilized to screen a library of such
nanosensors. Type II ZnSe CdS seeded nanorods were found to have the best
performance among the different nanosensors evaluated in this work. The degree
of correlation between intensity changes and spectral changes of the excitons
emission under applied field was characterized. An upper limit for the temporal
response of individual ZnSe CdS nanorods to voltage modulation was
characterized by high throughput, high temporal resolution intensity
measurements using a novel photon counting camera. The measured 3.5 us response
time is limited by the voltage modulation electronics and represents about 30
times higher bandwidth than needed for recording an action potential in a
neuron.Comment: 36 pages, 6 figure
Spatially coupled inversion of spectro-polarimetric image data I: Method and first results
When inverting solar spectra, image degradation effects that are present in
the data are usually approximated or not considered. We develop a data
reduction method that takes these issues into account and minimizes the
resulting errors. By accounting for the diffraction PSF of the telescope during
the inversions, we can produce a self-consistent solution that best fits the
observed data, while simultaneously requiring fewer free parameters than
conventional approaches. Simulations using realistic MHD data indicate that the
method is stable for all resolutions, including those with pixel scales well
beyond those that can be resolved with a 0.5m telescope, such as the Hinode
SOT. Application of the presented method to reduce full Stokes data from the
Hinode spectro-polarimeter results in dramatically increased image contrast and
an increase in the resolution of the data to the diffraction limit of the
telescope in almost all Stokes and fit parameters. The resulting data allow for
detecting and interpreting solar features that have so far only been observed
with 1m class ground-based telescopes. The new inversion method allows for
accurate fitting of solar spectro-polarimetric imaging data over a large field
of view, while simultaneously improving the noise statistics and spatial
resolution of the results significantly.Comment: A&A, accepte
Limits on Production of Magnetic Monopoles Utilizing Samples from the DO and CDF Detectors at the Tevatron
We present 90% confidence level limits on magnetic monopole production at the
Fermilab Tevatron from three sets of samples obtained from the D0 and CDF
detectors each exposed to a proton-antiproton luminosity of
(experiment E-882). Limits are obtained for the production cross-sections and
masses for low-mass accelerator-produced pointlike Dirac monopoles trapped and
bound in material surrounding the D0 and CDF collision regions. In the absence
of a complete quantum field theory of magnetic charge, we estimate these limits
on the basis of a Drell-Yan model. These results (for magnetic charge values of
1, 2, 3, and 6 times the minimum Dirac charge) extend and improve previously
published bounds.Comment: 18 pages, 17 figures, REVTeX
The Pierre Auger Observatory: Contributions to the 34th International Cosmic Ray Conference (ICRC 2015)
Contributions of the Pierre Auger Collaboration to the 34th International
Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The NetherlandsComment: 24 proceedings, the 34th International Cosmic Ray Conference, 30 July
- 6 August 2015, The Hague, The Netherlands; will appear in PoS(ICRC2015
- …