408 research outputs found
Injector Diagnostics Overview of SPIRAL2 Accelerator
International audienceThe SPIRAL2 project is based on a multi-beam driver in order to allow both ISOL and low-energy in-flight techniques to produce Radioactive Ion beams (RIB). A superconducting light/heavy-ion linac capable of accelerating 5 mA deuterons up to 40 MeV and 1 mA ions up to 14.5 MeV/u is used to bombard both thick and thin targets. These beams could be used for the production of intense RIB by several reaction mechanisms (fusion, fission, transfer, etc.). The post acceleration of RIB in the SPIRAL2 project is assured by the existing CIME cyclotron. SPIRAL2 beams, both before and after acceleration, can be used in the present experimental area of GANIL. The construction phase of SPIRAL2 is being started since the 1st of July 2005. An injector design overview is presented with diagnostics used to tune and qualify beams
SPIRAL 2 injector diagnostics
International audienceThe future SPIRAL2 facility will be composed of a multi-beam driver accelerator (5 mA/40 MeV deuterons, 5 mA /14.5 MeV/u heavy ions) and a dedicated building for the production of radioactive ion beams (RIBs). RIBs will be accelerated by the existing cyclotron CIME for the post acceleration and sent to GANIL's experimental areas. The injector constituted by an ion source a deuteron/proton source a L.E.B.T. and a M.E.B.T. lines and a room temperature R.F.Q. will produces, transports and accelerates beams up to an energy of 0.75 MeV/u. An Intermediate Test Bench (B.T.I.) is being built to commission the SPIRAL2 injector through the first rebuncher of the M.E.B.T. line in a first step and the last rebuncher in a second step. The B.T.I. is designed to perform a wide variety of measurements and functions and to go more deeply in the understanding of the behaviour of diagnostics under high average intensity beam operations. A superconducting LINAC equipped with two types of cavity will allow reaching 20 MeV/u for deuterons beam. This paper describes injector diagnostic developments and gives information about the current status
Preliminary implementation for the new SPIRAL2 project control system
International audienceThe Spiral2 project consists of a new facility to provide high intensity rare ions beams. It is based on a primary beam driver accelerator (RFQ followed by a superconducting linac) and a rare ion production process delivering the beam either to a low energy experimental area or to the existing Ganil facility. From October this year, one ion source coupled with a first beam line section will be in test; then, the injector (ion and deuteron sources, RFQ) will be tested by the end of 2010 so the whole accelerator should be commissioned by the end of 2011; the first exotic beams being planned one year later. The accelerator control system design results from the collaboration between several institutes and Epics has been chosen as the basic framework. The paper therefore presents the main choices: MVME5500 CPUs, VME I/O boards, VxWorks, Siemens PLCs, Modbus field buses, EDM screens and Java applications, Linux PCs, use of a LabView/Epics gateway... Specific topics are the evaluation of the XAL environment, an Epics design to address the power supplies, an emittance measurement system, the development of a beam profiler interface and the investigation for a triggered acquisition system
First step towards the new SPIRAL2 project control system
International audienceThe Spiral2 project at Ganil aims to produce rare ion beams using a Uranium carbide target fission process. The accelerator consists of a RFQ followed by a superconducting cavity linac and is designed to provide high intensity primary beams (deuterons, protons or heavy ions). The accelerator should be commissioned by the end of 2011; then, the first tests aiming to produce exotic beams are planned one year later. The control system will result of the collaboration between several institutes among which the Saclay Dapnia division yet having a good experience and knowledge with Epics. So and also because of its widely used functionalities, Epics has been chosen as the basic framework for the accelerator control and people from the other laboratories belonging to the collaboration are progressively acquiring a first experience with Epics. The paper first explains the organisation of the collaboration then it describes the basic hardware and software choices for the project. Some preliminary implementations are therefore given. As the project is still in its beginning phase, the paper ends by listing some interrogations not yet solved for the control system definition and opened for discussion
The silicon micro-strip detector plane for the LOFT/Wide Field Monitor
The main objective of the Wide Field Monitor (WFM) on the LOFT mission is to
provide unambiguous detection of the high-energy sources in a large field of
view, in order to support science operations of the LOFT primary instrument,
the LAD. The monitor will also provide by itself a large number of results on
the timing and spectral behaviour of hundreds of galactic compact objects,
Active Galactic Nuclei and Gamma-Ray Bursts. The WFM is based on the coded
aperture concept where a position sensitive detector records the shadow of a
mask projected by the celestial sources. The proposed WFM detector plane, based
on Double Sided micro-Strip Silicon Detectors (DSSD), will allow proper
2-dimensional recording of the projected shadows. Indeed the positioning of the
photon interaction in the detector with equivalent fine resolution in both
directions insures the best imaging capability compatible with the allocated
budgets for this telescope on LOFT. We will describe here the overall
configuration of this 2D-WFM and the design and characteristics of the DSSD
detector plane including its imaging and spectral performances. We will also
present a number of simulated results discussing the advantages that this
configuration offers to LOFT. A DSSD-based WFM will in particular reduce
significantly the source confusion experienced by the WFM in crowded regions of
the sky like the Galactic Center and will in general increase the observatory
science capability of the mission.Comment: Proceedings of SPIE, Vol. 8443, Paper No. 8443-89, 201
Development of an analogue optical link for the front-end read-out of the ATLAS electromagnetic calorimeter
We have developed an analogue optical data transmission system intended to meet the read-out requirements of the ATLAS liquid argon electromagnetic calorimeter. Eight-way demonstrators have been built and tested. The link uses arrays of VCSEL diodes as the optical emitters, coupled to a 70 m long fibre ribbon to simulate the distance between the detector and the control room. The receiver is based around a custom-designed PIN photodiode array. We describe here the final results of laboratory tests on a demonstrator, laying stress on the VCSEL-to-fibre coupling issues, and the overall performance of the full link. A 9-bit dynamic range is achieved, with a 5on-linearity
Background Light in Potential Sites for the ANTARES Undersea Neutrino Telescope
The ANTARES collaboration has performed a series of {\em in situ}
measurements to study the background light for a planned undersea neutrino
telescope. Such background can be caused by K decays or by biological
activity. We report on measurements at two sites in the Mediterranean Sea at
depths of 2400~m and 2700~m, respectively. Three photomultiplier tubes were
used to measure single counting rates and coincidence rates for pairs of tubes
at various distances. The background rate is seen to consist of three
components: a constant rate due to K decays, a continuum rate that
varies on a time scale of several hours simultaneously over distances up to at
least 40~m, and random bursts a few seconds long that are only correlated in
time over distances of the order of a meter. A trigger requiring coincidences
between nearby photomultiplier tubes should reduce the trigger rate for a
neutrino telescope to a manageable level with only a small loss in efficiency.Comment: 18 pages, 8 figures, accepted for publication in Astroparticle
Physic
The ANTARES Optical Beacon System
ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It
consists of a three dimensional array of photomultiplier tubes that can detect
the Cherenkov light induced by charged particles produced in the interactions
of neutrinos with the surrounding medium. High angular resolution can be
achieved, in particular when a muon is produced, provided that the Cherenkov
photons are detected with sufficient timing precision. Considerations of the
intrinsic time uncertainties stemming from the transit time spread in the
photomultiplier tubes and the mechanism of transmission of light in sea water
lead to the conclusion that a relative time accuracy of the order of 0.5 ns is
desirable. Accordingly, different time calibration systems have been developed
for the ANTARES telescope. In this article, a system based on Optical Beacons,
a set of external and well-controlled pulsed light sources located throughout
the detector, is described. This calibration system takes into account the
optical properties of sea water, which is used as the detection volume of the
ANTARES telescope. The design, tests, construction and first results of the two
types of beacons, LED and laser-based, are presented.Comment: 21 pages, 18 figures, submitted to Nucl. Instr. and Meth. Phys. Res.
Compton Large Area Silicon Timing Tracker for Cosmic Vision M3
International audienceProposed in response to the ESA call for the third Medium size mission (M3), CAPSiTT is a small mission designed for a 3-year survey of the non-thermal high energy sky from an equatorial LEO orbit. With a large effective area and a very wide field of view, its single instrument, a silicon tracker, provides good imaging, spectroscopic and polarimetric capabilities with a sensitivity 10-100 times better than COMPTEL. Nucleosynthesis and particle acceleration mechanisms in various sites are the main scientific topics addressed by CAPSiTT
Construction and test of a fine-grained liquid argon preshower prototype
A separate liquid argon preshower detector consisting of two layers featuring a fine granularity of 2.5~10 was studied by the RD3 collaboration. A prototype covering approximately 0.8 in pseudo-rapidity and 9 degrees in azimuth was built and tested at CERN in July 94. CMOS and GaAs VLSI preamplifiers were designed and tested for this occasion. The combined response of this detector and an accordion electromagnetic calorimeter prototype to muons, electrons and photons is presented. For minimum ionizing tracks a signal-to-noise ratio of 4.5 per preshower layer was measured. Above 150~GeV the space resolution for electrons is better than 250~m in both directions. The precision on the electromagnetic shower direction, determined together with the calorimeter, is better than 4 mrad above 50~GeV. It is concluded that the preshower detector would adequately fulfil its role for future operation at CERN Large Hadron Collider
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