1,439 research outputs found
Romanian 14 GHz ECR Ion Source RECRIS: main features and first operation
RECRIS, the romanian 14 GHz ECR ion source, designed to be used as a facility for atomic physics and material studies with highly charged ion beams, have been recently completed. The general design [1], the main characteristics and the detailed measurements of the radial [2] and axial magnetic fields are presented. A maximum axial magnetic field of 1.4 T and a mirror ratio of up to 4 were obtained. The dependence of the mirror ratio and of the ECR plasma zone volume on the configuration of the axial magnetic system configuration was studied. The first operation of this source is described, showing a good stability
Metal-dielectric structures for high charge state ion production in ECR plasma
Metal-dielectric (MD) structures of pure (99.999%) aluminum foils were previously studied [1, 2] in the National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest, Romania showing high secondary electron emission properties. Consequently, 26 mm diameter disks of such structures (Al-Al2O3) were tested in the ECR ion source of the Institut fuer Kernphysik (IKF) der J. W. Goethe Universitat, Frankfurt/Main, Germany, allowing to demonstrate their ability to significantly increase the ECRIS performances in what concerns the production of high charge state ions [3]. New experiments carried on in Bucharest on a special facility [2] stressed out the possibility to develop high emissive MD structures starting from lower purity (99%) aluminum foils. This result allowed us to make a special cylinder of 1 mm wall thickness electrolytically treated so that only the inner face had a MD structure layer while the external surface remained metallic. Such a cylinder introduced in the plasma chamber of an ECR ion source provides a high rate of secondary electrons that enhance the ECR plasma electron density while its metallic external surface provides a good electric and thermal contact with the plasma chamber. The tests performed with such a MD aluminum cylinder in the IKF 14 GHz ECR ion source, successfully demonstrated the possibility to shift the ECRIS output toward very high charge states (Ar16+) due to the strong secondary electron emission of the MD inner surface of the cylinder
Mining the ESO WFI and INT WFC archives for known Near Earth Asteroids. Mega-Precovery software
The ESO/MPG WFI and the INT WFC wide field archives comprising 330,000 images
were mined to search for serendipitous encounters of known Near Earth Asteroids
(NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 152 asteroids (44
PHAs and 108 other NEAs) were identified using the PRECOVERY software, their
astrometry being measured on 761 images and sent to the Minor Planet Centre.
Both recoveries and precoveries were reported, including prolonged orbital arcs
for 18 precovered objects and 10 recoveries. We analyze all new opposition data
by comparing the orbits fitted before and after including our contributions. We
conclude the paper presenting Mega-Precovery, a new online service focused on
data mining of many instrument archives simultaneously for one or a few given
asteroids. A total of 28 instrument archives have been made available for
mining using this tool, adding together about 2.5 million images forming the
Mega-Archive.Comment: Accepted for publication in Astronomische Nachrichten (Sep 2012
Radio Propagation Environment Analysis for Neutrino Radio Detection in Salt Mines
Abstract a We consider a neutrino large-scale radio Cherenkov observatory in a Romanian salt mine. We include propagation effects on the radio signal generated and make a threshold analysis, taking into account how the pulse couples to a realistic receiver and signal-to-noise ratio limiting situations
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Extremes on the discounted aggregate claims in a time dependent risk model
This paper presents an extension of the classical compound Poisson risk model for which the inter-claim time and the forthcoming claim amount are no longer independent random variables (rv's). Asymptotic tail probabilities for the discounted aggregate claims are presented when the force of interest is constant and the claim amounts are heavy tail distributed rv's. Furthermore, we derive asymptotic finite time ruin probabilities, as well as asymptotic approximations for some common risk measures associated with the discounted aggregate claims. A simulation study is performed in order to validate the results obtained in the free interest risk model
Performance and scalability of the back-end sub-system in the ATLAS DAQ/EF prototype
The DAQ group of the future ATLAS experiment has developed a prototype system based on the trigger/DAQ architecture described in the ATLAS Technical Proposal to support studies of the full system functionality, architecture as well as available hardware and software technologies. One sub-system of this prototype is the back- end which encompasses the software needed to configure, control and monitor the DAQ, but excludes the processing and transportation of physics data. The back-end consists of a number of components including run control, configuration databases and message reporting system. The software has been developed using standard, external software technologies such as OO databases and CORBA. It has been ported to several C++ compilers and operating systems including Solaris, Linux, WNT and LynxOS. This paper gives an overview of the back-end software, its performance, scalability and current status. (17 refs)
CONSIDERATIONS REGARDING THE PROCESS OF COMPACTION AND SOIL LOOSENING
The soil works are a series of agrotechnical operations that modify the physical condition of the soil using mechanical means. The purpose of the soil work is to create optimal conditions for the crop in order to obtain harvests as large as possible, through soil works being able influencing both the content of air, water and soil temperature and nutrient content adjustment. This paper presents some considerations concerning the characteristics and the properties of soil, respectively the measures to be taken to reduce compactness
Verification and Diagnostics Framework in ATLAS Trigger/DAQ
Trigger and data acquisition (TDAQ) systems for modern HEP experiments are
composed of thousands of hardware and software components depending on each
other in a very complex manner. Typically, such systems are operated by
non-expert shift operators, which are not aware of system functionality
details. It is therefore necessary to help the operator to control the system
and to minimize system down-time by providing knowledge-based facilities for
automatic testing and verification of system components and also for error
diagnostics and recovery. For this purpose, a verification and diagnostic
framework was developed in the scope of ATLAS TDAQ. The verification
functionality of the framework allows developers to configure simple low-level
tests for any component in a TDAQ configuration. The test can be configured as
one or more processes running on different hosts. The framework organizes tests
in sequences, using knowledge about components hierarchy and dependencies, and
allowing the operator to verify the functionality of any subset of the system.
The diagnostics functionality includes the possibility to analyze the test
results and diagnose detected errors, e.g. by starting additional tests and
understanding reasons of failures. A conclusion about system functionality,
error diagnosis and recovery advice are presented to the operator in a GUI. The
current implementation uses the CLIPS expert system shell for knowledge
representation and reasoning.Comment: Paper for the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003 (presented as poster). Format: PDF,
using MSWord template, 5 pages, 6 figures. PSN TUGP00
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