3,523 research outputs found
Passive mode-locking in semiconductor lasers with saturable absorbers bandgap shifted through quantum well intermixing
Passive mode-locking in semiconductor lasers in a Fabry–Perot configuration with a bandgap blueshift applied to the saturable absorber (SA) section has been experimentally characterized. For the first time a fully post-growth technique, quantum well intermixing, was adopted to modify the material bandgap in the SA section. The measurements showed not only an expected narrowing of the pulse width but also a significant expansion of the range of bias conditions generating a stable train of optical pulses. Moreover, the pulses from lasers with bandgap shifted absorbers presented reduced chirp and increased peak power with respect to the nonshifted case
MicroBooNE: A New Liquid Argon Time Projection Chamber Experiment
Liquid Argon Time Projection Chamber detectors are well suited to study
neutrino interactions, and are an intriguing option for future massive
detectors capable of measuring the parameters that characterize neutrino
oscillations. These detectors combine fine-grained tracking with calorimetry,
allowing for excellent imaging and particle identification ability. In this
talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be
exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be
presented. The ability of MicroBooNE to differentiate electrons from photons
gives the experiment unique capabilities in low energy neutrino interaction
measurements.Comment: Proceedings of the 6th International Workshop on Neutrino-Nucleus
Interactions in the Few-GeV Region (NuInt09
First Measurement of Muon Neutrino Charged Current Quasielastic (CCQE) Double Differential Cross Section
Using a high statistics sample of muon neutrino charged current quasielastic
(CCQE) events, we report the first measurement of the double differential cross
section as a function of muon energy and angle for this process. The result
features reduced model dependence and supplies the most complete information on
neutrino CCQE scattering to date. Measurements of the absolute cross section as
a function of neutrino energy and the single differential cross section as a
function of 4-momentum transfer squared are also provided, largely to
facilitate comparison with prior measurements. This data is of particular use
for understanding the axial-vector form factor of the nucleon as well as
improving the simulation of low energy neutrino interactions on nuclear
targets, which is of particular relevance for experiments searching for
neutrino oscillations.Comment: 6 pages, 6 figures, Proceedings of the 6th International Workshop on
Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09
Challenges in Extracting Charged Current Quasi-Elastic Model Information in MiniBooNE's Anti-Neutrino Data
Using a high-statistics sample of anti-neutrino charged current quasi-elastic
(CCQE) events, MiniBooNE reports the challenges in measuring parameters within
the Relativistic Fermi Gas model. As the CCQE analysis has been completed in
MiniBooNE's neutrino data, particular attention is paid to the differences in
CCQE interactions between the two running modes.Comment: NuInt '09 conference proceedings. Four pages, five figure
PCAC and coherent pion production by neutrinos
Coherent pion production in low energy neutrino reactions is discussed in the
framework of the partially conserved axial vector current theory (PCAC). The
role of lepton mass effects in suppressing production of positively charged
pions is discussed. Instead of using models of pion nucleus scattering, the
available data on pion carbon scattering are implemented for an analysis of the
PCAC prediction. Our results agree well with the published upper limits for
positively charged production but are much below the recent MiniBooNE result
for neutral pion production.Comment: 6 pages, 7 figures, writeup of talk presented at NUINT 200
High-extinction-ratio TE/TM selective Bragg grating filters on silicon-on-insulator
We report on the design and fabrication of TE and TM polarization selective Bragg grating filters in the form of sinusoidal perturbations on the waveguide sidewall and etched holes on the top of the waveguide, respectively. Combining the two geometries on a silicon-on-insulator waveguide resulted in Bragg grating filters with high extinction ratios of approximately 60 dB
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