110590916
NEMO: Status of the Project
The activities towards the realisation of a km 3 Cherenkov neutrino detector, carried out by the NEMO Collaboration are described. Long term exploration of a 3500 m deep site close to the Sicilian coast has shown that it is optimal for the installation of the detector. A complete feasibility study, that has considered all the components of the detector as well as its deployment, has been carried out demonstrating that technological solutions exist for the realization of an underwater km 3 detector. The realization of a technological demonstrator (the NEMO Phase 1 project) is under way.
109308730
Heavy-Ions induced SEE effects measurements for the STRURED ASIC
With the aim of developing a radiation-tolerant circuit, a digital test microelectronic device has been designed and fabricated by using a standard-cell library of a 130-nm CMOS technology, including three different architectures to correct circuit malfunctions induced by the occurrence of Single-Event Effects (SEEʼs). SEEʼs are one of the main reasons of failures affecting electronic circuits operating in harsh radiation environments, such as in experiments performed at High Energy Physics (HEP) colliders or in apparatus to be operated in Space. On the same digital circuit specifically designed, three redundant architectures added to a basic scheme have been implemented in order to evaluate their effectiveness to prevent SEE. This may give an indication on their usage in future digital circuits specifically designed for the above mentioned applications. We present the results of SEE cross section measurements performed on a test digital device exposed to a high energy heavy ion beam at the SIRAD irradiation facility of the INFN National Laboratories of Legnaro (Padova Italy).
109682907
Development realization and test of an electronic data acquisition board for the NEMO experiment
Abstract The development, realization and test of an electronic data acquisition-board for the NEutrino Mediterranean Observatory (NEMO) collaboration are described. The collaboration is involved in R&D of a deep underwater km 3 scale Cherenkov neutrino telescope in the southern Ionian Sea. Thousands of Optical Modules (OM), spread over the entire volume and supported by a three-dimensional structure, constitute the sensitive part of the detector. Each OM is equipped by a Photo-Multiplier Tube (PMT) and an electronic circuit for data acquisition and transmission (DAQ board). This work tries to point out the possible benefits of a hybrid solution based on an analog Application Specific Integrated Circuit (ASIC) employed for the analog acquisition, and a Field Programmable Gate Array (FPGA), a digital programmable Integrated Circuit (IC) which manages the acquisition and the data transmission.
61143114
Efficiency and readout architectures for large matrix of pixels
46500747
Implementation of a bidimensional compressor for a high-energy physics experiment
CARLOSv3 is the third version of a chip that plays a significant role in the data acquisition chain of the A Large Ion Collider Experiment (ALICE) silicon drift detector (SDD). ALICE is one of the foremost high-energy physics experiments (HEPE) conducted within the Large Hadron Collider at CERN, the European Organization for Nuclear Research in Geneva. CARLOSv3 was principally designed and built for the on-line compression of the input dataset originating from a physical bidimensional silicon sensor. To compress a bidimensional dataset, a bidimensional data compressor was required. The compressor was designed for the ALICE SDD Experiment but could be applied to all experiments in which an incoming stream dataset originates from a bidimensional sensor.
123625473
Architecture of a general purpose embedded Slow-Control Adapter ASIC for future high-energy physics experiments
Abstract This work is aimed at defining the architecture of a new digital ASIC, namely Slow-Control Adapter (SCA), which will be designed in a commercial 130-nm CMOS technology. This chip will be embedded within a high-speed data acquisition optical link (GBT) to control and monitor the front-end electronics in future high-energy physics experiments. The GBT link provides a transparent transport layer between the SCA and control electronics in the counting room. The proposed SCA supports a variety of common bus protocols to interface with end-user general-purpose electronics. Between the GBT and the SCA a standard 100 Mb/s IEEE-802.3 compatible protocol will be implemented. This standard protocol allows off-line tests of the prototypes using commercial components that support the same standard. The project is justified because embedded applications in modern large HEP experiments require particular care to assure the lowest possible power consumption, still offering the highest reliability demanded by very large particle detectors.
14845268
Real Space Statistical Properties of Standard Cosmological Models
After reviewing some basic relevant properties of stationary stochastic processes (SSP), we discuss the properties of the so‐called Harrison‐Zeldovich like spectra of mass density perturbations. These correlations are a fundamental feature of all current standard cosmological models. Examining them in real space we note they imply a sub‐poissonian normalized variance in spheres σM2(R) ∼ R−4 lnR. In particular this latter behavior is at the limit of the most rapid decay (∼ R−4) of this quantity possible for any stochastic distribution (continuous or discrete). In a simple classification of all SSP into three categories, we highlight with the name “super‐homogeneous” the properties of the class to which models like this, with P(0) = 0, belong. In statistical physics language they are well described as lattice or glass‐like. We illustrate their properties through two simple examples: (i) the “shuffled” lattice and the One Component Plasma at thermal equilibrium.
17991934
Gravitational evolution of a perturbed lattice and its fluid limit.
We apply a simple linearization, well known in solid state physics, to approximate the evolution at early times of cosmological N-body simulations of gravity. In the limit that the initial perturbations, applied to an infinite perfect lattice, are at wavelengths much greater than the lattice spacing l, the evolution is exactly that of a pressureless self-gravitating fluid treated in the analogous (Lagrangian) linearization, with the Zeldovich approximation as a subclass of asymptotic solutions. Our less restricted approximation allows one to trace the evolution of the discrete distribution until the time when particles approach one another (i.e., "shell crossing"). We calculate modifications of the fluid evolution, explicitly dependent on l, i.e., discreteness effects in the N-body simulations. We note that these effects become increasingly important as the initial redshift is increased at fixed l.
14013791
Initial Conditions, Discreteness and Non-Linear Structure Formation in Cosmology
In this lecture we address three different but related aspects of the initial continuous fluctuation field in standard cosmological models. Firstly we discuss the properties of the so-called Harrison-Zeldovich like spectra. This power spectrum is a fundamental feature of all current standard cosmological models. In a simple classification of all stationary stochastic processes into three categories, we highlight with the name “super- homogeneous” the properties of the class to which models like this, with P(0) = 0, belong. In statistical physics language they are well described as glass-like. Secondly, the initial continuous density field with such small amplitude correlated Gaussian fluctuations must be discretised in order to set up the initial particle distribution used in gravitational N-body simulations. We discuss the main issues related to the effects of discretisation, particularly concerning the effect of particle induced fluctuations on the statistical properties of the initial conditions and on the dynamical evolution of gravitational clustering.
119390803
Statistical Physics for Cosmic Structures
The recent observations of galaxy and dark matter clumpy distributions have provided new elements to the understanding of the problem of cosmological structure formation. The strong clumping characterizing galaxy structures seems to be present in the overall mass distribution and its relation to the highly isotropic Cosmic Microwave Background Radiation represents a fundamental problem. The extension of structures, the formation of power-law correlations characterizing the strongly clustered regime and the relation between dark and visible matter are the key problems both from an observational and a theoretical point of view. We discuss recent progresses in the studies of structure formation by using concepts and methods of statistical physics.
15853720
Galaxy number counts and fractal correlations
We report the correlation analysis of various redshift surveys which shows that the available data are consistent with each other and manifest fractal correlations (with dimension D 2) up to the present observational limits ( ≈ 150 h−1Mpc) without any tendency towards homogenization. This result points to a new interpretation of the number counts that represents the main subject of this letter. We show that an analysis of the small-scale fluctuations allows us to reconcile the correlation analysis and the number counts in a new perspective which has a number of important implications.