7619800
Latchup Topology for Pixel Readout Using Commercial Transistors
The stimulated ignition of latchup effects caused by external radiation has till now proved to be a hidden hazard. However this paper presents the effect in a new light-as a new approach for detecting particles by means of a solid-state device susceptible to latchup effects. This device can also be used as a circuit for reading a sensor's signal by leaving off-circuit sensing capabilities. Given that MOS transistors are widely used in microelectronics devices and sensors, the latchup-based cell is proposed as a new structure for future applications in particle detection, in the amplification of sensor signals and also in radiation monitoring.
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.
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).
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.
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.
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.
15654508
Gravitational force distribution in fractal structures
We study the (Newtonian) gravitational force distribution arising from a fractal set of sources. We show that, in the case of real structures in finite samples, an important role is played by morphological properties and finite-size effects. For dimensions smaller than d − 1 (being d the space dimension) the convergence of the net gravitational force is assured by the fast decaying of the density, while for fractal dimension D > d − 1 the morphological properties of the structure determine the eventual convergence of the force as a function of distance. We clarify the role played by the cut-offs of the distribution. Some cosmological implications are discussed.
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.
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.
125444963
Causality and the superhorizon power spectrum