No Arabic abstract
The european Fazia collaboration aims at building a new modular array for charged product identification to be employed for heavy-ion studies. The elementary module of the array is a Silicon-Silicon-CsI telescope, optimized for ion identification also via pulse shape analysis. The achievement of top performances imposes specific electronics which has been developed by FAZIA and features high quality charge and current preamplifiers, coupled to fully digital front-end. During the initial R&D phase, original and novel solutions have been tested in prototypes, obtaining unprecedented ion identification capabilities. FAZIA is now constructing a demonstrator array consisting of about two hundreds telescopes arranged in a compact and transportable configuration. In this contribution, we mainly summarize some aspects studied by FAZIA to improve the ion identification. Then we will briefly discuss the FAZIA program centered on experiments to be done with the demonstrator. First results on the isospin dynamics obtained with a reduced set-up demonstrate well the performance of the telescope and represent a good starting point towards future investigations with both stable and exotic beams.
In this work we present the architecture and results of a fully digital Front End Electronics (FEE) read out system developed for the GALILEO array. The FEE system, developed in collaboration with the Advanced Gamma Tracking Array (AGATA) collaboration, is composed of three main blocks: preamplifiers, digitizers and preprocessing electronics. The slow control system contains a custom Linux driver, a dynamic library and a server implementing network services. The digital processing of the data from the GALILEO germanium detectors has demonstrated the capability to achieve an energy resolution of 1.53 per mil at an energy of 1.33 MeV.
An upgraded GARFIELD + Ring Counter (RCo) apparatus is presented with improved performances as far as electronics and detectors are concerned. On one side fast sampling digital read out has been extended to all detectors, allowing for an important simplification of the signal processing chain together with an enriched extracted information. On the other side a relevant improvement has been made in the forward part of the setup (RCo): an increased granularity of the CsI(Tl) crystals and a higher homogeneity in the silicon detector resistivity. The renewed performances of the GARFIELD + RCo array make it suitable for nuclear reaction measurements both with stable and with Radioactive Ion Beams (RIB), like the ones foreseen for the SPES facility, where the Physics of Isospin can be studied.
The Timepix particle tracking telescope has been developed as part of the LHCb VELO Upgrade project, supported by the Medipix Collaboration and the AIDA framework. It is a primary piece of infrastructure for the VELO Upgrade project and is being used for the development of new sensors and front end technologies for several upcoming LHC trackers and vertexing systems. The telescope is designed around the dual capability of the Timepix ASICs to provide information about either the deposited charge or the timing information from tracks traversing the 14 x 14mm matrix of 55 x 55 um pixels. The rate of reconstructed tracks available is optimised by taking advantage of the shutter driven readout architecture of the Timepix chip, operated with existing readout systems. Results of tests conducted in the SPS North Area beam facility at CERN show that the telescope typically provides reconstructed track rates during the beam spills of between 3.5 and 7.5 kHz, depending on beam conditions. The tracks are time stamped with 1 ns resolution with an efficiency of above 98% and provide a pointing resolution at the centre of the telescope of 1.6 um . By dropping the time stamping requirement the rate can be increased to 15 kHz, at the expense of a small increase in background. The telescope infrastructure provides CO2 cooling and a flexible mechanical interface to the device under test, and has been used for a wide range of measurements during the 2011-2012 data taking campaigns.
FAZIA is designed for detailed studies of the isospin degree of freedom, extending to the limits the isotopic identification of charged products from nuclear collisions when using silicon detectors and CsI(Tl) scintillators. We show that the FAZIA telescopes give isotopic identification up to Z$sim$25 with a $Delta$E-E technique. Digital Pulse Shape Analysis makes possible elemental identification up to Z=55 and isotopic identification for Z=1-10 when using the response of a single silicon detector. The project is now in the phase of building a demonstrator comprising about 200 telescopes.
An experimental setup is being developed to extract Ba ions from a high-pressure Xe gas environment. It aims to transport Ba ions from 10 bar Xe to vacuum conditions. The setup utilizes a converging-diverging nozzle in combination with a radio-frequency (RF) funnel to move Ba ions into vacuum through the pressure drop of several orders of magnitude. This technique is intended to be used in a future multi-ton detector investigating double-beta decay in $^{136}$Xe. Efficient extraction and detection of Ba ions, the decay product of Xe, would allow for a background-free measurement of the $^{136}$Xe double-beta decay.