110623274
Fast readout logic interfacing a 256-pixel matrix of a dual-layer 3D device
A prototype of a 3D ASIC built up of a fast readout architecture, with sparsification capabilities, which interfaces with a matrix of a 256-pixel sensor, was recently submitted. The chosen technology is CMOS Chartered 130 nm as it is compatible with the Tezzaron facility to interconnect face-to-face two silicon wafers allowing for a vertical integration structure by means of through-silicon-vias. Particularly, the readout logic uses one layer that will be stacked on a sensor layer at the end of the fabrication process.
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).
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.
56367755
Design of an integrated particle detector-cell based on latchup effect
The paper describes an innovative idea for a silicon pixel detector. The principle is based on latchup effect that is common in to-date CMOS technologies working in a radiation environment. A prototype was constructed in the past with commercial components and here is described in detail an integrated version of the design. In principle the detector has low triggering and dead time, can operate at room temperature, does not require a high voltage power supply and is intrinsically tolerant to radiation. As a latchup-based detector can be constructed using state-of-the-art CMOS technologies, here it is presented a design of a prototype that will be implemented on a commercial 0.35 μm Bi-CMOS technology and tested at Electronics Department of Torino Politecnico.
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.
109494522
Design, realization and test of a rad-hard 2D-compressor and packing chip for high energy physics experiments
CARLOSv3 is a third version of a chip that plays a significant role in the data acquisition chain of the A Large Ion Collider Experiment Inner Tracking System experiment. It has been designed and realized with a 0.25 μm CMOS 3-metal rad-hard digital library. The chip elaborates and compresses, by means of a bi-dimensional compressor, data belonging to a so-called event. The compressor looks for cross-shaped clusters within the whole data set coming from the silicon detector. To test the chip a specific PCB has been designed; it contains the connectors for probing the ASIC with a pattern generator and a logic state analyzer. The chip is inserted on the PCB using a ZIF socket. This allows to test the 35 packaged samples out of the total amount of bare chips we have from the foundry. The test phase has shown that 32 out of 35 chips under test work well. It is planned to redesign a new version of the chip by adding extra features and to submit the final version of CARLOS upon the final DAQ chain will be totally tested both in Bologna and at CERN.
14253637
Finite size effects on the galaxy number counts: Evidence for fractal behavior up to the deepest scale
We introduce and study two new concepts which are essential for the quantitative analysis of the statistical quality of the available galaxy samples. These are the dilution effect and the small scale fluctuations. We show that the various data that are considered as pointing to a homogenous distribution are all affected by these spurious effects and their interpretation should be completely changed. In particular, we show that finite size effects strongly affect the determination of the galaxy number counts, namely the number versus magnitude relation (N (< m)) as computed from the origin. When one computes N (< m) averaged over all the points of a redshift survey, one observes an exponent α = D/5 ≈ 0.4 compatible with the fractal dimension D ≈ 2 derived from the full correlation analysis. Instead the observation of an exponent α ≈ 0.6 at relatively small scales, where the distribution is certainly not homogeneous, is shown to be related to finite size effects. We conclude therefore that the observed counts correspond to a fractal distribution with dimension D ≈ 2 in the entire range 12 ⪅ m ⪅ 28, that is to say the largest scales ever probed for luminous matter. In addition our results permit to clarify various problems of the angular catalogs, and to show their compatibility with the fractal behaviour. We consider also the distribution of Radio-galaxies, Quasars and γ-ray bursts, and we show their compatibility with a fractal structure with D ≈ 1.6–1.8. Finally we have established a quantitative criterion that allows us to define and predict the statistical validity of a galaxy catalog (angular or three-dimensional).
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.
119442907
Glass-like universe: Real-space correlation properties of standard cosmological models
After reviewing the basic relevant properties of stationary stochastic processes (SSP), defining basic terms and quantities, we discuss the properties of the so-called Harrison-Zeldovich like spectra. These correlations, usually characterized exclusively in k space [i.e., in terms of power spectra $P(k)],$ are a fundamental feature of all current standard cosmological models. Examining them in real space we note their characteristics to be a negative power law tail $\ensuremath{\xi}(r)\ensuremath{\sim}\ensuremath{-}{r}^{\ensuremath{-}4},$ and a sub-Poissonian normalized variance in spheres ${\ensuremath{\sigma}}^{2}(R)\ensuremath{\sim}{R}^{\ensuremath{-}4}\mathrm{ln}R.$ We note in particular that this latter behavior is at the limit of the most rapid decay $(\ensuremath{\sim}{R}^{\ensuremath{-}4})$ of this quantity possible for any stochastic distribution (continuous or discrete). This very particular characteristic is usually obscured in cosmology by the use of Gaussian spheres. In a simple classification of all SSP into three categories, we highlight with the name ``superhomogeneous'' the properties of the class to which models such as this, with $P(0)=0,$ belong. In statistical physics language they are well described as glass-like. They have neither ``scale-invariant'' features, in the sense of critical phenomena, nor fractal properties. We illustrate their properties with some simple examples, in particular that of a ``shuffled'' lattice.
116902937
Correlation and Clustering
In this lecture we clarify the basic difference between the correlation properties for systems characterized by small or large fluctuations. The concepts of correlation length, homogeneity scale, scale invariance and criticality are discussed as well. We relate these concepts to the interpretation of galaxy clsutering.
14719850
Persistent fluctuations and scaling properties in galaxy number counts
Counts of galaxies as a function of apparent magnitude are among the most time-honored observations in cosmology. In this Letter, we focus on some statistical properties of these counts which are fundamental in order to characterize the large scale correlations in the galaxy spatial distribution. There are, in fact, no longer doubts since two decades of the existence of very large scale structures. The still remaining problem concerns the correct characterization of their statistical properties. We propose to study two properties of galaxy counts data, in order to discriminate between a small scale (~ 5 - 20 Mpc/h) homogeneous distribution, and a fractal structure on large scales (~ 20 - 300 Mpc/h). Firstly, the average slope of the counts which can be associated to an eventual fractal dimension in real space by simple arguments. Secondly, we propose to study fluctuations of counts around the average behavior as a function of apparent magnitude in the whole magnitude range B_j > 11. These fluctuations can discriminate between a genuine fractal distribution and a homogeneous one. In fact, they are related to the very statistical properties of the spatial distribution, independently on cosmological corrections. More specifically, in a fractal distribution one expects to find persistent scale-invariant fluctuations around the average behavior, which do not decay with apparent magnitude. On the other hand, in an homogeneous distribution, on large enough scales, the relative variance of the counts should decrease exponentially with apparent magnitude. Smooth cosmological corrections cannot change such a behavior.