203 research outputs found
Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Data Handling Overview
The GLAST Balloon Flight Engineering Model (BFEM) represents one of 16 towers
that constitute the Large Area Telescope (LAT), a high-energy (>20 MeV)
gamma-ray pair-production telescope being built by an international partnership
of astrophysicists and particle physicists for a satellite launch in 2006. The
prototype tower consists of a Pb/Si pair-conversion tracker (TKR), a CsI
hodoscopic calorimeter (CAL), an anti-coincidence detector (ACD) and an
autonomous data acquisition system (DAQ). The self-triggering capabilities and
performance of the detector elements have been previously characterized using
positron, photon and hadron beams. External target scintillators were placed
above the instrument to act as sources of hadronic showers. This paper provides
a comprehensive description of the BFEM data-reduction process, from receipt of
the flight data from telemetry through event reconstruction and background
rejection cuts. The goals of the ground analysis presented here are to verify
the functioning of the instrument and to validate the reconstruction software
and the background-rejection scheme.Comment: 5 pages, 4 figures, to be published in IEEE Transacations on Nuclear
Science, August 200
DEVELOPMENT OF ADAPTIVE RESONATOR TECHNIQUES FOR HIGH-POWER LASERS
The design of an adaptive wavefront control system for a high-power Nd:Glass laser will be presented. Features of this system include: an unstable resonator in confocal configuration, a multi-module slab amplifier, and real-time intracavity adaptive phase control using deformable mirrors and high-speed wavefront sensors. Experimental results demonstrate the adaptive correction of an aberrated passive resonator (no gain)
The dynamics of entry, exit and profitability: an error correction approach for the retail industry
We develop a two equation error correction model to investigate determinants of and dynamic interaction between changes in profits and number of firms in retailing. An explicit distinction is made between the effects of actual competition among incumbants, new firms competition and potential competition from firms outside the market. Effects of cost, demand and general income changes on profitability are investigated to gain insight in the role of retailing in the cost, demand and wage inflationary processes. The relative importance of profitability, growth and unemployment as determinants of net entry are studied. The model is tested using a panel data set of 36 Dutch shoptypes covering the 1977–1988 period
The On-orbit Calibrations for the Fermi Large Area Telescope
The Large Area Telescope (LAT) on--board the Fermi Gamma ray Space Telescope
began its on--orbit operations on June 23, 2008. Calibrations, defined in a
generic sense, correspond to synchronization of trigger signals, optimization
of delays for latching data, determination of detector thresholds, gains and
responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA),
measurements of live time, of absolute time, and internal and spacecraft
boresight alignments. Here we describe on orbit calibration results obtained
using known astrophysical sources, galactic cosmic rays, and charge injection
into the front-end electronics of each detector. Instrument response functions
will be described in a separate publication. This paper demonstrates the
stability of calibrations and describes minor changes observed since launch.
These results have been used to calibrate the LAT datasets to be publicly
released in August 2009.Comment: 60 pages, 34 figures, submitted to Astroparticle Physic
Compuestos volátiles libres y enlazados glicosĂdicamente en la pulpa de la uva Caimarona (Pourouma cecropiifolia Mart.)
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