16,900 research outputs found
Linear Accelerator Test Facility at LNF Conceptual Design Report
Test beam and irradiation facilities are the key enabling infrastructures for
research in high energy physics (HEP) and astro-particles. In the last 11 years
the Beam-Test Facility (BTF) of the DA{\Phi}NE accelerator complex in the
Frascati laboratory has gained an important role in the European
infrastructures devoted to the development and testing of particle detectors.
At the same time the BTF operation has been largely shadowed, in terms of
resources, by the running of the DA{\Phi}NE electron-positron collider. The
present proposal is aimed at improving the present performance of the facility
from two different points of view: extending the range of application for the
LINAC beam extracted to the BTF lines, in particular in the (in some sense
opposite) directions of hosting fundamental physics and providing electron
irradiation also for industrial users; extending the life of the LINAC beyond
or independently from its use as injector of the DA{\Phi}NE collider, as it is
also a key element of the electron/positron beam facility. The main lines of
these two developments can be identified as: consolidation of the LINAC
infrastructure, in order to guarantee a stable operation in the longer term;
upgrade of the LINAC energy, in order to increase the facility capability
(especially for the almost unique extracted positron beam); doubling of the BTF
beam-lines, in order to cope with the signicant increase of users due to the
much wider range of applications.Comment: 71 page
RF System Upgrades to the Advanced Photon Source Linear Accelerator in Support of the Fel Operation
The S-band linear accelerator, which was built to be the source of particles
and the front end of the Advanced Photon Source injector, is now also being
used to support a low-energy undulator test line (LEUTL) and to drive a
free-electron laser (FEL). The more severe rf stability requirements of the FEL
have resulted in an effort to identify sources of phase and amplitude
instability and implement corresponding upgrades to the rf generation chain and
the measurement system. Test data and improvements implemented and planned are
describedComment: LC 2000 (3 pages, 6 figures
Compact personal distributed wearable exposimeter
A compact wearable personal distributed exposimeter (PDE) is proposed, sensing the power density of incident radio frequency (RF) fields on the body of a human. In contrast to current commercial exposimeters, our PDE, being composed of multiple compact personal wearable RF exposimeter sensor modules, minimizes uncertainties caused by the proximity of the body, the specific antenna used, and the exact position of the exposimeter. For unobtrusive deployment inside a jacket, each individual exposimeter sensor module is specifically implemented on the feedplane of a textile patch antenna. The new wearable sensor module's high-resolution logarithmic detector logs RF signal levels. Next, on-board flash memory records minimum, maximum, and average exposure data over a time span of more than two weeks, at a one-second sample period. Sample-level synchronization of each individual exposimeter sensor module enables combining of measurements collected by different nodes. The system is first calibrated in an anechoic chamber, and then compared with a commercially available single-unit exposimeter. Next, the PDE is validated in realistic conditions, by measuring the average RF power density on a human during a walk in an urban environment and comparing the results to spectrum analyzer measurements with a calibrated antenna
Initial test results on bolometers for the Planck high frequency instrument
We summarize the fabrication, flight qualification, and dark performance of bolometers completed at the Jet Propulsion Laboratory for the High Frequency Instrument (HFI) of the joint ESA/NASA Herschel/Planck mission to be launched in 2009. The HFI is a multicolor focal plane which consists of 52 bolometers operated at 100 mK. Each bolometer is mounted to a feedhorn-filter assembly which defines one of six frequency bands centered between 100-857 GHz. Four detectors in each of five bands from 143-857 GHz are coupled to both linear polarizations and thus measure the total intensity. In addition, eight detectors in each of four bands (100, 143, 217, and 353 GHz) couple only to a single linear polarization and thus provide measurements of the Stokes parameters, Q and U, as well as the total intensity. The measured noise equivalent power (NEP) of all detectors is at or below the background limit for the telescope and time constants are a few ms, short enough to resolve point sources as the 5 to 9 arc min beams move across the sky at 1 rpm
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