European column buckling curves and finite element modelling including high strength steels

DEFF Research Database (Denmark)

Jönsson, Jeppe; Stan, Tudor-Cristian

2017-01-01

Eurocode allows for finite element modelling of plated steel structures, however the information in the code on how to perform the analysis or what assumptions to make is quite sparse. The present paper investigates the deterministic modelling of flexural column buckling using plane shell elements...... imperfections may be very conservative if considered by finite element analysis as described in the current Eurocode code. A suggestion is given for a slightly modified imperfection formula within the Ayrton-Perry formulation leading to adequate inclusion of modern high grade steels within the original four...... bucking curves. It is also suggested that finite element or frame analysis may be performed with equivalent column bow imperfections extracted directly from the Ayrton-Perry formulation....

The alignment of the ATLAS Inner Detector in Run 2

CERN Document Server

Ripellino, Giulia; The ATLAS collaboration

2016-01-01

The ATLAS reconstruction of charged particle trajectories relies on the Inner Detector tracking system. The accuracy of the reconstruction is limited by the finite resolution of the detector elements and the knowledge about their positions. A precise alignment of the detector is therefore essential. In this poster we present the strategy and the status of the Inner Detector alignment in ATLAS during the LHC Run 2.

The Development of Micro-Pattern Gas Detectors

CERN Document Server

BALOUZA, Samah

2014-01-01

This work is aimed to study the electron transparency in 3-D woven mesh that is used in micromegas detector. The importance of calculating the transparency is because it is enter in the gain calibration of the detector. The simulation tool is COMSOL Multiphysics in which it is solved the differential equations by Finite Element Method.

A Monte Carlo tool for evaluating VMAT and DIMRT treatment deliveries including planar detectors

International Nuclear Information System (INIS)

Asuni, G; Van Beek, T A; Venkataraman, S; McCurdy, B M C; Popescu, I A

2013-01-01

The aim of this work is to describe and validate a new general research tool that performs Monte Carlo (MC) simulations for volumetric modulated arc therapy (VMAT) and dynamic intensity modulated radiation therapy (DIMRT), simultaneously tracking dose deposition in both the patient CT geometry and an arbitrary planar detector system. The tool is generalized to handle either entrance or exit detectors and provides the simulated dose for the individual control-points of the time-dependent VMAT and DIMRT deliveries. The MC simulation tool was developed with the EGSnrc radiation transport. For the individual control point simulation, we rotate the patient/phantom volume only (i.e. independent of the gantry and planar detector geometries) using the gantry angle in the treatment planning system (TPS) DICOM RP file such that each control point has its own unique phantom file. After MC simulation, we obtained the total dose to the phantom by summing dose contributions for all control points. Scored dose to the sensitive layer of the planar detector is available for each control point. To validate the tool, three clinical treatment plans were used including VMAT plans for a prostate case and a head-and-neck case, and a DIMRT plan for a head-and-neck case. An electronic portal imaging device operated in ‘movie’ mode was used with the VMAT plans delivered to cylindrical and anthropomorphic phantoms to validate the code using an exit detector. The DIMRT plan was delivered to a novel transmission detector, to validate the code using an entrance detector. The total MC 3D absolute doses in patient/phantom were compared with the TPS doses, while 2D MC doses were compared with planar detector doses for all individual control points, using the gamma evaluation test with 3%/3 mm criteria. The MC 3D absolute doses demonstrated excellent agreement with the TPS doses for all the tested plans, with about 95% of voxels having γ 90% of percentage pixels with γ <1. We found that over

Self-Powered Neutron Detector Qualification for Absolute On-Line In-Pile Neutron Flux Measurements in BR2

Science.gov (United States)

Vermeeren, L.; Wéber, M.

2003-06-01

A set of ten Self-Powered Neutron Detectors with Co, Rh and Ag emitters has been irradiated in several channels of the BR2 research reactor at SCK•CEN aiming at a comparison of their performance as thermal neutron flux detectors under various conditions. To allow for a correct interpretation of their signals, all detector sensitivity contributions (prompt and delayed) were calculated using a dedicated Monte Carlo model. The various contributions were also measured separately; the agreement between calculated and experimental data, including data from activation dosimetry, was excellent. Detailed neutron flux profiles were obtained from the SPND data, after correction for the finite detector lengths and for the slow response of delayed SPNDs.

Detector Mount Design for IGRINS

Directory of Open Access Journals (Sweden)

Jae Sok Oh

2014-06-01

Full Text Available The Immersion Grating Infrared Spectrometer (IGRINS is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

Three-dimensional cross point readout detector design for including depth information

Science.gov (United States)

Lee, Seung-Jae; Baek, Cheol-Ha

2018-04-01

We designed a depth-encoding positron emission tomography (PET) detector using a cross point readout method with wavelength-shifting (WLS) fibers. To evaluate the characteristics of the novel detector module and the PET system, we used the DETECT2000 to perform optical photon transport in the crystal array. The GATE was also used. The detector module is made up of four layers of scintillator arrays, the five layers of WLS fiber arrays, and two sensor arrays. The WLS fiber arrays in each layer cross each other to transport light to each sensor array. The two sensor arrays are coupled to the forward and left sides of the WLS fiber array, respectively. The identification of three-dimensional pixels was determined using a digital positioning algorithm. All pixels were well decoded, with the system resolution ranging from 2.11 mm to 2.29 mm at full width at half maximum (FWHM).

Detector simulation needs for detector designers

International Nuclear Information System (INIS)

Hanson, G.G.

1987-11-01

Computer simulation of the components of SSC detectors and of the complete detectors will be very important for the designs of the detectors. The ratio of events from interesting physics to events from background processes is very low, so detailed understanding of detector response to the backgrounds is needed. Any large detector for the SSC will be very complex and expensive and every effort must be made to design detectors which will have excellent performance and will not have to undergo major rebuilding. Some areas in which computer simulation is particularly needed are pattern recognition in tracking detectors and development of shower simulation code which can be trusted as an aid in the design and optimization of calorimeters, including their electron identification performance. Existing codes require too much computer time to be practical and need to be compared with test beam data at energies of several hundred GeV. Computer simulation of the processing of the data, including electronics response to the signals from the detector components, processing of the data by microprocessors on the detector, the trigger, and data acquisition will be required. In this report we discuss the detector simulation needs for detector designers

Development library of finite elements for computer-aided design system of reed sensors

Science.gov (United States)

Kozlov, A. S.; Shmakov, N. A.; Tkalich, V. L.; Labkovskaia, R. I.; Kalinkina, M. E.; Pirozhnikova, O. I.

2018-05-01

The article is devoted to the development of a modern highly reliable element base of devices for security and fire alarm systems, in particular, to the improvement of the quality of contact cores (reed and membrane) of reed sensors. Modeling of elastic sensitive elements uses quadrangular elements of plates and shells, considered in the system of curvilinear orthogonal coordinates. The developed mathematical models and the formed finite element library are designed for systems of automated design of reed switch detectors to create competitive devices alarms. The finite element library is used for the automated system production of reed switch detectors both in series production and in the implementation of individual orders.

Unfolding of true distributions from experimental data distorted by detectors with finite resolutions

International Nuclear Information System (INIS)

Gagunashvili, N.D.

1993-01-01

A new procedure for unfolding the true distribution from experimental data distorted by a detector is proposed. For the given detector a result can be found by the least squares method, hence, without bias and involving minimal statistical errors. Stability of the result is achieved at the expense of its information content and/or using additional information on the shape of the distributions to be measured. The method may be applied for detectors with linear or nonlinear distortions. 8 refs.; 5 figs

Finite rotation shells basic equations and finite elements for Reissner kinematics

CERN Document Server

Wisniewski, K

2010-01-01

This book covers theoretical and computational aspects of non-linear shells. Several advanced topics of shell equations and finite elements - not included in standard textbooks on finite elements - are addressed, and the book includes an extensive bibliography.

Estimation of ex-core detector responses by adjoint Monte Carlo

Energy Technology Data Exchange (ETDEWEB)

Hoogenboom, J. E. [Delft Univ. of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

2006-07-01

Ex-core detector responses can be efficiently calculated by combining an adjoint Monte Carlo calculation with the converged source distribution of a forward Monte Carlo calculation. As the fission source distribution from a Monte Carlo calculation is given only as a collection of discrete space positions, the coupling requires a point flux estimator for each collision in the adjoint calculation. To avoid the infinite variance problems of the point flux estimator, a next-event finite-variance point flux estimator has been applied, witch is an energy dependent form for heterogeneous media of a finite-variance estimator known from the literature. To test the effects of this combined adjoint-forward calculation a simple geometry of a homogeneous core with a reflector was adopted with a small detector in the reflector. To demonstrate the potential of the method the continuous-energy adjoint Monte Carlo technique with anisotropic scattering was implemented with energy dependent absorption and fission cross sections and constant scattering cross section. A gain in efficiency over a completely forward calculation of the detector response was obtained, which is strongly dependent on the specific system and especially the size and position of the ex-core detector and the energy range considered. Further improvements are possible. The method works without problems for small detectors, even for a point detector and a small or even zero energy range. (authors)

Infrared finiteness in Yang--Mills theories

International Nuclear Information System (INIS)

Appelquist, T.; Carazzone, J.; Kluberg-Stern, H.; Roth, M.

1976-01-01

The infrared divergences of renormalizable theories with coupled massless fields (in particular, the Yang--Mills theory) are shown to cancel for transition probabilities corresponding to finite-energy-resolution detectors, just as in quantum electrodynamics. This result is established through lowest nontrivial order in perturbation theory for the detection of massive muons in a quantum electrodynamic theory containing massless electrons or the detection of massive quarks in a Yang--Mills theory

An analysis of the control hierarchy modelling of the CMS detector control system

NARCIS (Netherlands)

Hwong, Y.L.; Groote, J.F.; Willemse, T.A.C.

2009-01-01

The high level Detector Control System (DCS) of the CMS experiment is modelled using Finite State Machines (FSM), which cover the control application behaviours of all the sub-detectors and support services. The Joint Controls Project (JCOP) at CERN has chosen the SMI++ framework for this purpose.

Complete Tangent Stiffness for eXtended Finite Element Method by including crack growth parameters

DEFF Research Database (Denmark)

Mougaard, J.F.; Poulsen, P.N.; Nielsen, L.O.

2013-01-01

the crack geometry parameters, such as the crack length and the crack direction directly in the virtual work formulation. For efficiency, it is essential to obtain a complete tangent stiffness. A new method in this work is presented to include an incremental form the crack growth parameters on equal terms......The eXtended Finite Element Method (XFEM) is a useful tool for modeling the growth of discrete cracks in structures made of concrete and other quasi‐brittle and brittle materials. However, in a standard application of XFEM, the tangent stiffness is not complete. This is a result of not including...... with the degrees of freedom in the FEM‐equations. The complete tangential stiffness matrix is based on the virtual work together with the constitutive conditions at the crack tip. Introducing the crack growth parameters as direct unknowns, both equilibrium equations and the crack tip criterion can be handled...

Finite Element Analysis of the SciFi-Nomex-Sandwich Panels

CERN Document Server

Schultz von Dratzig, Arndt

2015-01-01

A finite element analysis of the SciFi-Nomex-sandwich panels has been carried out in order to investigate their thermo-mechanical properties. This does not include the cooling of the silicon photomultipliers but is restricted to the panels themselves. Two kinds of panels have been considered: panels with 40 mm thickness and panels with 50 mm thickness. Both versions are equipped with mats of six layers of scintillating fibers. The analyses were carried out for a series of mechanical and thermal loads which might occur during the production or installation of the detector. For both versions the stiffnesses prove to be sufficient and no critical stresses or strains are found.

Finite element computational fluid mechanics

International Nuclear Information System (INIS)

Baker, A.J.

1983-01-01

This book analyzes finite element theory as applied to computational fluid mechanics. It includes a chapter on using the heat conduction equation to expose the essence of finite element theory, including higher-order accuracy and convergence in a common knowledge framework. Another chapter generalizes the algorithm to extend application to the nonlinearity of the Navier-Stokes equations. Other chapters are concerned with the analysis of a specific fluids mechanics problem class, including theory and applications. Some of the topics covered include finite element theory for linear mechanics; potential flow; weighted residuals/galerkin finite element theory; inviscid and convection dominated flows; boundary layers; parabolic three-dimensional flows; and viscous and rotational flows

ACTIV, Sandwich Detector Activity from In-Pile Slowing-Down Spectra Experiment

International Nuclear Information System (INIS)

Bozzi, L. and others

1978-01-01

1 - Nature of physical problem solved: Calculates the activities of a sandwich detector, to be used for in-pile measurements in slowing-down spectra below a few keV. The effect of scattering with energy degradation in the filter and in the detectors has been included to a first approximation. 2 - Method of solution: An iterative procedure is used: the calculation starts with a flux guess in which one assumes that each measured reactivity difference depends on the principal resonance only. The secondary resonance contribution is computed through the iterative process. For self-shielded cross-section calculations the model of Pearlstein and Weinstock (ref. 3) is used. The neutron spectrum can optionally be constant or 1/E inside each finite energy group relative to the resonance considered. 3 - Restrictions on the complexity of the problem: Maximum number of energy groups : 60

Basic Finite Element Method

International Nuclear Information System (INIS)

Lee, Byeong Hae

1992-02-01

This book gives descriptions of basic finite element method, which includes basic finite element method and data, black box, writing of data, definition of VECTOR, definition of matrix, matrix and multiplication of matrix, addition of matrix, and unit matrix, conception of hardness matrix like spring power and displacement, governed equation of an elastic body, finite element method, Fortran method and programming such as composition of computer, order of programming and data card and Fortran card, finite element program and application of nonelastic problem.

Forward modeling of space-borne gravitational wave detectors

International Nuclear Information System (INIS)

Rubbo, Louis J.; Cornish, Neil J.; Poujade, Olivier

2004-01-01

Planning is underway for several space-borne gravitational wave observatories to be built in the next 10 to 20 years. Realistic and efficient forward modeling will play a key role in the design and operation of these observatories. Space-borne interferometric gravitational wave detectors operate very differently from their ground-based counterparts. Complex orbital motion, virtual interferometry, and finite size effects complicate the description of space-based systems, while nonlinear control systems complicate the description of ground-based systems. Here we explore the forward modeling of space-based gravitational wave detectors and introduce an adiabatic approximation to the detector response that significantly extends the range of the standard low frequency approximation. The adiabatic approximation will aid in the development of data analysis techniques, and improve the modeling of astrophysical parameter extraction

High-Resolution Gamma-Ray Imaging Measurements Using Externally Segmented Germanium Detectors

Science.gov (United States)

Callas, J.; Mahoney, W.; Skelton, R.; Varnell, L.; Wheaton, W.

1994-01-01

Fully two-dimensional gamma-ray imaging with simultaneous high-resolution spectroscopy has been demonstrated using an externally segmented germanium sensor. The system employs a single high-purity coaxial detector with its outer electrode segmented into 5 distinct charge collection regions and a lead coded aperture with a uniformly redundant array (URA) pattern. A series of one-dimensional responses was collected around 511 keV while the system was rotated in steps through 180 degrees. A non-negative, linear least-squares algorithm was then employed to reconstruct a 2-dimensional image. Corrections for multiple scattering in the detector, and the finite distance of source and detector are made in the reconstruction process.

Design and construction of a uniform magnetic field generator for a 32 channel cosmic ray detector

Science.gov (United States)

Herrera-Guzman, K. N.; Gutierrez-Sanchez, R. A.; Felix, J.; Arceo, L. J.; Araujo, C.

2017-10-01

The trajectory of a particle can be measured if some points of its track are known. This is applied to any kind of particle, including cosmic rays. We have designed and built a device for this purpose. We present the design, construction and characterization of a uniform magnetic field generator system in a finite volume. An array of Cerenkov detectors will be placed inside of it for determining the cosmic rays charge and to reconstruct their trajectories.

A correction for emittance-measurement errors caused by finite slit and collector widths

International Nuclear Information System (INIS)

Connolly, R.C.

1992-01-01

One method of measuring the transverse phase-space distribution of a particle beam is to intercept the beam with a slit and measure the angular distribution of the beam passing through the slit using a parallel-strip collector. Together the finite widths of the slit and each collector strip form an acceptance window in phase space whose size and orientation are determined by the slit width, the strip width, and the slit-collector distance. If a beam is measured using a detector with a finite-size phase-space window, the measured distribution is different from the true distribution. The calculated emittance is larger than the true emittance, and the error depends both on the dimensions of the detector and on the Courant-Snyder parameters of the beam. Specifically, the error gets larger as the beam drifts farther from a waist. This can be important for measurements made on high-brightness beams, since power density considerations require that the beam be intercepted far from a waist. In this paper we calculate the measurement error and we show how the calculated emittance and Courant-Snyder parameters can be corrected for the effects of finite sizes of slit and collector. (Author) 5 figs., 3 refs

Position detectors, methods of detecting position, and methods of providing positional detectors

Science.gov (United States)

Weinberg, David M.; Harding, L. Dean; Larsen, Eric D.

2002-01-01

Position detectors, welding system position detectors, methods of detecting various positions, and methods of providing position detectors are described. In one embodiment, a welding system positional detector includes a base that is configured to engage and be moved along a curved surface of a welding work piece. At least one position detection apparatus is provided and is connected with the base and configured to measure angular position of the detector relative to a reference vector. In another embodiment, a welding system positional detector includes a weld head and at least one inclinometer mounted on the weld head. The one inclinometer is configured to develop positional data relative to a reference vector and the position of the weld head on a non-planar weldable work piece.

The digital flat-panel X-Ray detectors

International Nuclear Information System (INIS)

Risticj, S. Goran

2013-01-01

In a digital imaging system, the incident x-ray image must be sampled both in the spatial and intensity dimensions. In the spatial dimensions, samples are obtained as averages of the intensity over picture elements or pixels. In the intensity dimension, the signal is digitalized into one of a finite number of levels or bits. Two main types of digital flat-panel detectors are based on the direct conversion, which contains the photoconductor, and on indirect conversion, which contains phosphor. The basics of these detectors are given. Coupling traditional x-ray detection material such as photoconductors and phosphors with a large-area active-matrix readout structure forms the basis of flat panel x-ray images. Active matrix technology provides a new, highly efficient, real time method for electronically storing and measuring the product of the x-ray interaction stage whether the product is visible wavelength photons or electrical charges. The direct and indirect detectors, made as the active-matrix flat-panel detectors containing sensing/storage elements, switching elements (diodes or thin film transistors (TFTS)) and image processing module, are described. Strengths and limitations of stimulable phosphors are discussed. The main advantages and disadvantages of mentioned x-ray detectors are also analyzed. (Author)

A combined multibody and finite element approach for dynamic interaction analysis of high-speed train and railway structure including post-derailment behavior during an earthquake

International Nuclear Information System (INIS)

Tanabe, M; Wakui, H; Sogabe, M; Matsumoto, N; Tanabe, Y

2010-01-01

A combined multibody and finite element approach is given to solve the dynamic interaction of a Shinkansen train (high-speed train in Japan) and the railway structure including post-derailment during an earthquake effectively. The motion of the train is expressed in multibody dynamics. Efficient mechanical models to express interactions between wheel and track structure including post-derailment are given. Rail and track elements expressed in multibody dynamics and FEM are given to solve contact problems between wheel and long railway components effectively. The motion of a railway structure is modeled with various finite elements and rail and track elements. The computer program has been developed for the dynamic interaction analysis of a Shinkansen train and railway structure including post derailment during an earthquake. Numerical examples are demonstrated.

Finite elements and approximation

CERN Document Server

Zienkiewicz, O C

2006-01-01

A powerful tool for the approximate solution of differential equations, the finite element is extensively used in industry and research. This book offers students of engineering and physics a comprehensive view of the principles involved, with numerous illustrative examples and exercises.Starting with continuum boundary value problems and the need for numerical discretization, the text examines finite difference methods, weighted residual methods in the context of continuous trial functions, and piecewise defined trial functions and the finite element method. Additional topics include higher o

Detector development and test facility

International Nuclear Information System (INIS)

Reeder, D.D.

1993-01-01

Following the ideas presented in the proposal to the DoE, we have begun to acquire the equipment needed to design, develop construct and test the electronic and mechanical features of detectors used in High Energy Physics Experiments. A guiding principle for the effort is to achieve integrated electronic and mechanical designs which meet the demanding specifications of the modern hadron collider environment yet minimize costs. This requires state of the art simulation of signal processing as well as detailed calculations of heat transfer and finite element analysis of structural integrity

Finite-dimensional calculus

International Nuclear Information System (INIS)

Feinsilver, Philip; Schott, Rene

2009-01-01

We discuss topics related to finite-dimensional calculus in the context of finite-dimensional quantum mechanics. The truncated Heisenberg-Weyl algebra is called a TAA algebra after Tekin, Aydin and Arik who formulated it in terms of orthofermions. It is shown how to use a matrix approach to implement analytic representations of the Heisenberg-Weyl algebra in univariate and multivariate settings. We provide examples for the univariate case. Krawtchouk polynomials are presented in detail, including a review of Krawtchouk polynomials that illustrates some curious properties of the Heisenberg-Weyl algebra, as well as presenting an approach to computing Krawtchouk expansions. From a mathematical perspective, we are providing indications as to how to implement infinite terms Rota's 'finite operator calculus'.

Cherenkov water detector NEVOD

Science.gov (United States)

Petrukhin, A. A.

2015-05-01

A unique multipurpose Cherenkov water detector, the NEVOD facility, uses quasispherical measuring modules to explore all the basic components of cosmic rays on Earth's surface, including neutrinos. Currently, the experimental complex includes the Cherenkov water detector, a calibration telescope system, and a coordinate detector. This paper traces the basic development stages of NEVOD, examines research directions, presents the results obtained, including the search for the solution to the 'muon puzzle', and discusses possible future development prospects.

A first principle approach for clover detector

Science.gov (United States)

Kshetri, R.

2012-08-01

A simple model based on probability flow arguments has been presented for understanding the clover germanium detector. Using basic concepts of absorption and scattering of gamma-rays, the operation of the clover detector has been described in terms of six probability amplitudes and a parameter. Instead of using an empirical method or simulation, this work presents the first attempt to calculate the peak-to-total and peak-to-background ratios of the clover detector using experimental data of relative single crystal efficiency and addback factor as an input. A unique feature of our approach is that these ratios could be calculated for energies where their direct measurement is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. Results for four gamma-ray energies (Eγ = 1.408, 3.907, 7.029 and 10.430 MeV) have been discussed. Agreement between experimental data and analysis results has been observed. The present approach could describe clover-type detectors as well. As an example, the nine element detector has been considered. We have demonstrated that our formalism can describe both finite and infinite interactions of γ-rays with the clover crystals. The work presented in this paper follows similar philosophy as presented in a recent paper (R. Kshetri, JInst 2012 7 P04008), which deals with modeling of encapsulated type composite detectors like miniball, cluster and SPI (Spectrometer for INTEGRAL satellite).

A first principle approach for clover detector

International Nuclear Information System (INIS)

Kshetri, R

2012-01-01

A simple model based on probability flow arguments has been presented for understanding the clover germanium detector. Using basic concepts of absorption and scattering of gamma-rays, the operation of the clover detector has been described in terms of six probability amplitudes and a parameter. Instead of using an empirical method or simulation, this work presents the first attempt to calculate the peak-to-total and peak-to-background ratios of the clover detector using experimental data of relative single crystal efficiency and addback factor as an input. A unique feature of our approach is that these ratios could be calculated for energies where their direct measurement is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. Results for four gamma-ray energies (E γ = 1.408, 3.907, 7.029 and 10.430 MeV) have been discussed. Agreement between experimental data and analysis results has been observed. The present approach could describe clover-type detectors as well. As an example, the nine element detector has been considered. We have demonstrated that our formalism can describe both finite and infinite interactions of γ-rays with the clover crystals. The work presented in this paper follows similar philosophy as presented in a recent paper (R. Kshetri, JInst 2012 7 P04008), which deals with modeling of encapsulated type composite detectors like miniball, cluster and SPI (Spectrometer for INTEGRAL satellite).

Finite element study of a HDR-RPV-section including a nozzle under thermal shock transient

Energy Technology Data Exchange (ETDEWEB)

Roos, E [Stuttgart Univ. (Germany); Katzenmeier, G [Forschungszentrum Juelich GmbH (Germany); Wanner, R; Mercier, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1988-12-31

This document presents a finite element study of a reactor pressure vessel section under thermal stresses. The strength properties of the vessel walls are studied as well as cracks due to the thermo-shock transient. (TEC). 6 refs.

Analytical approximations to the Hotelling trace for digital x-ray detectors

Science.gov (United States)

Clarkson, Eric; Pineda, Angel R.; Barrett, Harrison H.

2001-06-01

The Hotelling trace is the signal-to-noise ratio for the ideal linear observer in a detection task. We provide an analytical approximation for this figure of merit when the signal is known exactly and the background is generated by a stationary random process, and the imaging system is an ideal digital x-ray detector. This approximation is based on assuming that the detector is infinite in extent. We test this approximation for finite-size detectors by comparing it to exact calculations using matrix inversion of the data covariance matrix. After verifying the validity of the approximation under a variety of circumstances, we use it to generate plots of the Hotelling trace as a function of pairs of parameters of the system, the signal and the background.

Finite fields and applications

CERN Document Server

Mullen, Gary L

2007-01-01

This book provides a brief and accessible introduction to the theory of finite fields and to some of their many fascinating and practical applications. The first chapter is devoted to the theory of finite fields. After covering their construction and elementary properties, the authors discuss the trace and norm functions, bases for finite fields, and properties of polynomials over finite fields. Each of the remaining chapters details applications. Chapter 2 deals with combinatorial topics such as the construction of sets of orthogonal latin squares, affine and projective planes, block designs, and Hadamard matrices. Chapters 3 and 4 provide a number of constructions and basic properties of error-correcting codes and cryptographic systems using finite fields. Each chapter includes a set of exercises of varying levels of difficulty which help to further explain and motivate the material. Appendix A provides a brief review of the basic number theory and abstract algebra used in the text, as well as exercises rel...

Detectors for Particle Radiation

Science.gov (United States)

Kleinknecht, Konrad

1999-01-01

This textbook provides a clear, concise and comprehensive review of the physical principles behind the devices used to detect charged particles and gamma rays, and the construction and performance of these many different types of detectors. Detectors for high-energy particles and radiation are used in many areas of science, especially particle physics and nuclear physics experiments, nuclear medicine, cosmic ray measurements, space sciences and geological exploration. This second edition includes all the latest developments in detector technology, including several new chapters covering micro-strip gas chambers, silicion strip detectors and CCDs, scintillating fibers, shower detectors using noble liquid gases, and compensating calorimeters for hadronic showers. This well-illustrated textbook contains examples from the many areas in science in which these detectors are used. It provides both a coursebook for students in physics, and a useful introduction for researchers in other fields.

Computation of the magnetic field of a spectrometer in detectors region

International Nuclear Information System (INIS)

Zhidkov, E.P.; Yuldasheva, M.B.; Yudin, I.P.; Yuldashev, O.I.

1995-01-01

Computed results of the 3D magnetic field of a spectrometer intended for investigation of hadron production of charmed particles and the indication of the narrow resonances in neutron-nucleus interactions are presented. The methods used in computations: finite element method and finite element method with suggested new infinite elements are described. For accuracy control the computations were carried out on a sequence of three-dimensional meshes. Special attention is devoted to behaviour of the magnetic field in the basic detector (proportional chambers) region. The performed results can be used for the field behaviour estimate of similar spectrometer magnets. (orig.)

Optimization of the two-sample rank Neyman-Pearson detector

Science.gov (United States)

Akimov, P. S.; Barashkov, V. M.

1984-10-01

The development of optimal algorithms concerned with rank considerations in the case of finite sample sizes involves considerable mathematical difficulties. The present investigation provides results related to the design and the analysis of an optimal rank detector based on a utilization of the Neyman-Pearson criteria. The detection of a signal in the presence of background noise is considered, taking into account n observations (readings) x1, x2, ... xn in the experimental communications channel. The computation of the value of the rank of an observation is calculated on the basis of relations between x and the variable y, representing interference. Attention is given to conditions in the absence of a signal, the probability of the detection of an arriving signal, details regarding the utilization of the Neyman-Pearson criteria, the scheme of an optimal rank, multichannel, incoherent detector, and an analysis of the detector.

Finite Metric Spaces of Strictly negative Type

DEFF Research Database (Denmark)

Hjorth, Poul G.

If a finite metric space is of strictly negative type then its transfinite diameter is uniquely realized by an infinite extent (“load vector''). Finite metric spaces that have this property include all trees, and all finite subspaces of Euclidean and Hyperbolic spaces. We prove that if the distance...

Structural modeling techniques by finite element method

International Nuclear Information System (INIS)

Kang, Yeong Jin; Kim, Geung Hwan; Ju, Gwan Jeong

1991-01-01

This book includes introduction table of contents chapter 1 finite element idealization introduction summary of the finite element method equilibrium and compatibility in the finite element solution degrees of freedom symmetry and anti symmetry modeling guidelines local analysis example references chapter 2 static analysis structural geometry finite element models analysis procedure modeling guidelines references chapter 3 dynamic analysis models for dynamic analysis dynamic analysis procedures modeling guidelines and modeling guidelines.

Summary of activity. Topic I: detectors and experiments. [High-energy detectors for use at ISABELLE

Energy Technology Data Exchange (ETDEWEB)

Marx, J; Ozaki, S

1978-01-01

Results of a workshop studying detectors for Isabelle experimental halls are described. The detectors must be very reliable. Spatial resolution of the tracking detectors must be high to provide accurate measurements of angle and momentum, retain a short resolving time, and show excellent multiparticle handling capability. Included in the study were hodoscopes, drift chambers, proportional chambers, time projection chambers, Cherenkov counters, electromagnetic shower detectors, and hadron calorimeters. Data handling methods were also included in the studies. (FS)

Finite element methods a practical guide

CERN Document Server

Whiteley, Jonathan

2017-01-01

This book presents practical applications of the finite element method to general differential equations. The underlying strategy of deriving the finite element solution is introduced using linear ordinary differential equations, thus allowing the basic concepts of the finite element solution to be introduced without being obscured by the additional mathematical detail required when applying this technique to partial differential equations. The author generalizes the presented approach to partial differential equations which include nonlinearities. The book also includes variations of the finite element method such as different classes of meshes and basic functions. Practical application of the theory is emphasised, with development of all concepts leading ultimately to a description of their computational implementation illustrated using Matlab functions. The target audience primarily comprises applied researchers and practitioners in engineering, but the book may also be beneficial for graduate students.

Computation of the Magnetic Field of a Spectrometer in Detectors Region

International Nuclear Information System (INIS)

Zhidkov, E.P.; Yuldasheva, M.B.; Yudin, I.P.; Yuldashev, O.I.

1994-01-01

Computed results of the 3D magnetic field of a spectrometer intended for investigation of hadron production of charmed particles and the indication of the narrow resonances in neutron-nucleus interaction are presented. The methods, used in computations - finite element method and finite element method with suggested new infinite elements are described. For accuracy control the computations were carried out on a sequence of three-dimensional meshes. Special attention is devoted to the behaviour of the magnetic field in the basic detectors (proportional chambers) region. The performed results can be used for the field behaviour estimate of similar spectrometer magnets. 12 refs., 16 figs

On characters of finite groups

CERN Document Server

Broué, Michel

2017-01-01

This book explores the classical and beautiful character theory of finite groups. It does it by using some rudiments of the language of categories. Originally emerging from two courses offered at Peking University (PKU), primarily for third-year students, it is now better suited for graduate courses, and provides broader coverage than books that focus almost exclusively on groups. The book presents the basic tools, notions and theorems of character theory (including a new treatment of the control of fusion and isometries), and introduces readers to the categorical language at several levels. It includes and proves the major results on characteristic zero representations without any assumptions about the base field. The book includes a dedicated chapter on graded representations and applications of polynomial invariants of finite groups, and its closing chapter addresses the more recent notion of the Drinfeld double of a finite group and the corresponding representation of GL_2(Z).

Basic Radiation Detectors. Chapter 6

Energy Technology Data Exchange (ETDEWEB)

Van Eijk, C. W.E. [Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands)

2014-12-15

Radiation detectors are of paramount importance in nuclear medicine. The detectors provide a wide range of information including the radiation dose of a laboratory worker and the positron emission tomography (PET) image of a patient. Consequently, detectors with strongly differing specifications are used. In this chapter, general aspects of detectors are discussed.

Probing Sub-GeV Dark Matter with Conventional Detectors

DEFF Research Database (Denmark)

Kouvaris, Chris; Pradler, Josef

2017-01-01

The direct detection of dark matter particles with mass below the GeV scale is hampered by soft nuclear recoil energies and finite detector thresholds. For a given maximum relative velocity, the kinematics of elastic dark matter nucleus scattering sets a principal limit on detectability. Here, we...... propose to bypass the kinematic limitations by considering the inelastic channel of photon emission from bremsstrahlung in the nuclear recoil. Our proposed method allows us to set the first limits on dark matter below 500 MeV in the plane of dark matter mass and cross section with nucleons. In situations...... where a dark-matter-electron coupling is suppressed, bremsstrahlung may constitute the only path to probe low-mass dark matter awaiting new detector technologies with lowered recoil energy thresholds....

HP Ge planar detectors

International Nuclear Information System (INIS)

Gornov, M.G.; Gurov, Yu.B.; Soldatov, A.M.; Osipenko, B.P.; Yurkowski, J.; Podkopaev, O.I.

1989-01-01

Parameters of planar detectors manufactured of HP Ge are presented. The possibilities to use multilayer spectrometers on the base of such semiconductor detectors for nuclear physics experiments are discussed. It is shown that the obtained detectors including high square ones have spectrometrical characteristics close to limiting possible values. 9 refs.; 3 figs.; 1 tab

Sound radiation from finite surfaces

DEFF Research Database (Denmark)

Brunskog, Jonas

2013-01-01

A method to account for the effect of finite size in acoustic power radiation problem of planar surfaces using spatial windowing is developed. Cremer and Heckl presents a very useful formula for the power radiating from a structure using the spatially Fourier transformed velocity, which combined...... with spatially windowing of a plane waves can be used to take into account the finite size. In the present paper, this is developed by means of a radiation impedance for finite surfaces, that is used instead of the radiation impedance for infinite surfaces. In this way, the spatial windowing is included...

CCD-based vertex detectors

CERN Document Server

Damerell, C J S

2005-01-01

Over the past 20 years, CCD-based vertex detectors have been used to construct some of the most precise 'tracking microscopes' in particle physics. They were initially used by the ACCMOR collaboration for fixed target experiments in CERN, where they enabled the lifetimes of some of the shortest-lived charm particles to be measured precisely. The migration to collider experiments was accomplished in the SLD experiment, where the original 120 Mpixel detector was later upgraded to one with 307 Mpixels. This detector was used in a range of physics studies which exceeded the capability of the LEP detectors, including the most precise limit to date on the Bs mixing parameter. This success, and the high background hit densities that will inevitably be encountered at the future TeV-scale linear collider, have established the need for a silicon pixel-based vertex detector at this machine. The technical options have now been broadened to include a wide range of possible silicon imaging technologies as well as CCDs (mon...

Shielded regenerative neutron detector

International Nuclear Information System (INIS)

Terhune, J.H.; Neissel, J.P.

1978-01-01

An ion chamber type neutron detector is disclosed which has a greatly extended lifespan. The detector includes a fission chamber containing a mixture of active and breeding material and a neutron shielding material. The breeding and shielding materials are selected to have similar or substantially matching neutron capture cross-sections so that their individual effects on increased detector life are mutually enhanced

Electron-phonon coupling from finite differences

Science.gov (United States)

Monserrat, Bartomeu

2018-02-01

The interaction between electrons and phonons underlies multiple phenomena in physics, chemistry, and materials science. Examples include superconductivity, electronic transport, and the temperature dependence of optical spectra. A first-principles description of electron-phonon coupling enables the study of the above phenomena with accuracy and material specificity, which can be used to understand experiments and to predict novel effects and functionality. In this topical review, we describe the first-principles calculation of electron-phonon coupling from finite differences. The finite differences approach provides several advantages compared to alternative methods, in particular (i) any underlying electronic structure method can be used, and (ii) terms beyond the lowest order in the electron-phonon interaction can be readily incorporated. But these advantages are associated with a large computational cost that has until recently prevented the widespread adoption of this method. We describe some recent advances, including nondiagonal supercells and thermal lines, that resolve these difficulties, and make the calculation of electron-phonon coupling from finite differences a powerful tool. We review multiple applications of the calculation of electron-phonon coupling from finite differences, including the temperature dependence of optical spectra, superconductivity, charge transport, and the role of defects in semiconductors. These examples illustrate the advantages of finite differences, with cases where semilocal density functional theory is not appropriate for the calculation of electron-phonon coupling and many-body methods such as the GW approximation are required, as well as examples in which higher-order terms in the electron-phonon interaction are essential for an accurate description of the relevant phenomena. We expect that the finite difference approach will play a central role in future studies of the electron-phonon interaction.

A comprehensive analysis of irradiated silicon detectors at cryogenic temperatures

CERN Document Server

Santocchia, A; Hall, G; MacEvoy, B; Moscatelli, F; Passeri, D; Pignatel, Giogrio Umberto

2003-01-01

The effect of particle irradiation on high-resistivity silicon detectors has been extensively studied with the goal of engineering devices able to survive the very challenging radiation environment at the CERN Large Hadron Collider (LHC). The main aspect under investigation has been the changes observed in detector effective doping concentration (N/sub eff/). We have previously proposed a mechanism to explain the evolution of N/sub eff/, whereby charge is exchanged directly between closely-spaced defect centres in the dense terminal clusters formed by hadron irradiation. This model has been implemented in both a commercial finite-element device simulator (ISE-TCAD) and a purpose-built simulation of interdefect charge exchange. To control the risk of breakdown due to the high leakage currents foreseen during ten years of LHC operation, silicon detectors will be operated below room temperature (around -10 degrees C). This, and more general current interest in the field of cryogenic operation, has led us to inve...

Silicon Pixel Detectors for Synchrotron Applications

CERN Document Server

Stewart, Graeme Douglas

Recent advances in particle accelerators have increased the demands being placed on detectors. Novel detector designs are being implemented in many different areas including, for example, high luminosity experiments at the LHC or at next generation synchrotrons. The purpose of this thesis was to characterise some of these novel detectors. The first of the new detector types is called a 3D detector. This design was first proposed by Parker, Kenney and Segal (1997). In this design, doped electrodes are created that extend through the silicon substrate. When compared to a traditional photodiode with electrodes on the opposing surfaces, the 3D design can combine a reasonable detector thickness with a small electrode spacing resulting in fast charge collection and limited charge sharing. The small electrode spacing leads to the detectors having lower depletion voltages. This, combined with the fast collection time, makes 3D detectors a candidate for radiation hard applications. These applications include the upgra...

Position-sensitive X-ray detectors

International Nuclear Information System (INIS)

Hendrix, J.

1982-01-01

An overview is given of the different types of position-sensitive X-ray detectors used in kinetic studies of biological molecule state changes using X-ray diffraction with synchrotron radiation as a probe. The detector requirements and principles of operation of proportional counters are outlined. Multiwire proportional chamber systems and their readout techniques are described. Other detectors discussed include a drift chamber type detector, microchannel plates, charge-couple devices and, for high count rates, an integrating TV-detector. (U.K.)

Monte Carlo simulation of the response functions of Cd Te detectors to be applied in X-rays spectroscopy

International Nuclear Information System (INIS)

Tomal, A.; Lopez G, A. H.; Santos, J. C.; Costa, P. R.

2014-08-01

In this work, the energy response functions of a Cd Te detector were obtained by Monte Carlo simulation in the energy range from 5 to 150 keV, using the Penelope code. The response functions simulated included the finite detector resolution and the carrier transport. The simulated energy response matrix was validated through comparison with experimental results obtained for radioactive sources. In order to investigate the influence of the correction by the detector response at diagnostic energy range, x-ray spectra were measured using a Cd Te detector (model Xr-100-T, Amptek), and then corrected by the energy response of the detector using the stripping procedure. Results showed that the Cd Te exhibit good energy response at low energies (below 40 keV), showing only small distortions on the measured spectra. For energies below about 70 keV, the contribution of the escape of Cd- and Te-K x-rays produce significant distortions on the measured x-ray spectra. For higher energies, the most important correction is the detector efficiency and the carrier trapping effects. The results showed that, after correction by the energy response, the measured spectra are in good agreement with those provided by different models from the literature. Finally, our results showed that the detailed knowledge of the response function and a proper correction procedure are fundamental for achieve more accurate spectra from which several qualities parameters (i.e. half-value layer, effective energy and mean energy) can be determined. (Author)

Monte Carlo simulation of the response functions of Cd Te detectors to be applied in X-rays spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tomal, A. [Universidade Federale de Goias, Instituto de Fisica, Campus Samambaia, 74001-970, Goiania, (Brazil); Lopez G, A. H.; Santos, J. C.; Costa, P. R., E-mail: alessandra_tomal@yahoo.com.br [Universidade de Sao Paulo, Instituto de Fisica, Rua du Matao Travessa R. 187, Cidade Universitaria, 05508-090 Sao Paulo (Brazil)

2014-08-15

In this work, the energy response functions of a Cd Te detector were obtained by Monte Carlo simulation in the energy range from 5 to 150 keV, using the Penelope code. The response functions simulated included the finite detector resolution and the carrier transport. The simulated energy response matrix was validated through comparison with experimental results obtained for radioactive sources. In order to investigate the influence of the correction by the detector response at diagnostic energy range, x-ray spectra were measured using a Cd Te detector (model Xr-100-T, Amptek), and then corrected by the energy response of the detector using the stripping procedure. Results showed that the Cd Te exhibit good energy response at low energies (below 40 keV), showing only small distortions on the measured spectra. For energies below about 70 keV, the contribution of the escape of Cd- and Te-K x-rays produce significant distortions on the measured x-ray spectra. For higher energies, the most important correction is the detector efficiency and the carrier trapping effects. The results showed that, after correction by the energy response, the measured spectra are in good agreement with those provided by different models from the literature. Finally, our results showed that the detailed knowledge of the response function and a proper correction procedure are fundamental for achieve more accurate spectra from which several qualities parameters (i.e. half-value layer, effective energy and mean energy) can be determined. (Author)

New developments in PET detector technology

International Nuclear Information System (INIS)

Niu Lingxin; Zhao Shujun; Zhang Bin; Liu Haojia

2010-01-01

The researches on PET detector are always active and innovative area. The research direction of PET detector includes improving performances of scintillator-based detectors, investigating new detectors suitable for multi-modality imaging (e.g. PET/CT and PET/MRI), meeting requirements of TOF and DOI technologies and boosting the development of the technologies. In this paper, new developments in PET detector technology about scintillation crystal, photodetector and semiconductor detector is introduced. (authors)

An introduction to finite projective planes

CERN Document Server

Albert, Abraham Adrian

2015-01-01

Geared toward both beginning and advanced undergraduate and graduate students, this self-contained treatment offers an elementary approach to finite projective planes. Following a review of the basics of projective geometry, the text examines finite planes, field planes, and coordinates in an arbitrary plane. Additional topics include central collineations and the little Desargues' property, the fundamental theorem, and examples of finite non-Desarguesian planes.Virtually no knowledge or sophistication on the part of the student is assumed, and every algebraic system that arises is defined and

Probing Sub-GeV Dark Matter with Conventional Detectors.

Science.gov (United States)

Kouvaris, Chris; Pradler, Josef

2017-01-20

The direct detection of dark matter particles with mass below the GeV scale is hampered by soft nuclear recoil energies and finite detector thresholds. For a given maximum relative velocity, the kinematics of elastic dark matter nucleus scattering sets a principal limit on detectability. Here, we propose to bypass the kinematic limitations by considering the inelastic channel of photon emission from bremsstrahlung in the nuclear recoil. Our proposed method allows us to set the first limits on dark matter below 500 MeV in the plane of dark matter mass and cross section with nucleons. In situations where a dark-matter-electron coupling is suppressed, bremsstrahlung may constitute the only path to probe low-mass dark matter awaiting new detector technologies with lowered recoil energy thresholds.

Shock Interaction with a Finite Thickness Two-Gas Interface

Science.gov (United States)

Labenski, John; Kim, Yong

2006-03-01

A dual-driver shock tube was used to investigate the growth rate of a finite thickness two-gas interface after shock forcing. One driver was used to create an argon-refrigerant interface as the contact surface behind a weak shock wave. The other driver, at the opposite end of the driven section, generates a stronger shock of Mach 1.1 to 1.3 to force the interface back in front of the detector station. Two schlieren systems record the density fluctuations while light scattering detectors record the density of the refrigerant as a function of position over the interface during both it's initial passage and return. A pair of digital cameras take stereo images of the interface, as mapped out by the tracer particles under illumination by a Q-switched ruby laser. The amount of time that the interface is allowed to travel up the driven section determines the interaction time as a control. Comparisons made between the schlieren signals, light scattering detector outputs, and the images quantify the fingered characteristics of the interface and its growth due to shock forcing. The results show that the interface has a distribution of thicknesses and that the interaction with a shock further broadens the interface.

Limitations of the pulse-shape technique for particle discrimination in planar Si detectors

International Nuclear Information System (INIS)

Pausch, G.; Seidel, W.; Lampert, M.O.; Rohr, P.

1996-11-01

Limitations of the pulse-shape discrimination (PSD) technique - a promising method to identify the charged particles stopped in planar Si-detectors - have been investigated. The particle resolution turned out to be basically determined by resistivity fluctuations in the bulk silicon which cause the charge-collection time to depend on the point of impact. Detector maps showing these fluctuations have been measured and are discussed. Furthermore we present a simple method to test the performance of detectors with respect to PSD. Another limitation of the PSD technique is the finite energy threshold for particle identification. This threshold is caused by an unexpected decrease of the total charge-collection time for ions with a short range, in spite of the fact that the particle tracks are located in a region of very low electric field. (orig.)

Ruggedization of CdZnTe detectors and detector assemblies for radiation detection applications

Energy Technology Data Exchange (ETDEWEB)

Lu, P.H., E-mail: pinghe.lu@redlen.com; Gomolchuk, P.; Chen, H.; Beitz, D.; Grosser, A.W.

2015-06-01

This paper described improvements in the ruggedization of CdZnTe detectors and detector assemblies for use in radiation detection applications. Research included experimenting with various conductive and underfill adhesive material systems suitable for CZT substrates. A detector design with encapsulation patterning was developed to protect detector surfaces and to control spacing between CZT anode and PCB carrier. Robustness of bare detectors was evaluated through temperature cycling and metallization shear testing. Attachment processes using well-chosen adhesives and PCB carrier materials were optimized to improve reliability of detector assemblies, resulted in Improved Attachment Detector Assembly. These detector assemblies were subjected to aggressive temperature cycling, and varying levels of drop/shock and vibration, in accordance with modified JEDEC, ANSI and FedEx testing standards, to assess their ruggedness. Further enhanced detector assembly ruggedization methods were investigated involving adhesive conformal coating, potting and dam filling on detector assemblies, which resulted in the Enhanced Ruggedization Detector Assembly. Large numbers of CZT detectors and detector assemblies with 5 mm and 15 mm thick, over 200 in total, were tested. Their performance was evaluated by exposure to various radioactive sources using comprehensive predefined detector specifications and testing protocols. Detector assemblies from improved attachment and enhanced ruggedization showed stable performances during the harsh environmental condition tests. In conclusion, significant progress has been made in improving the reliability and enhancing the ruggedness of CZT detector assemblies for radiation detection applications deployed in operational environments. - Highlights: • We developed ruggedization methods to enhance reliability of CZT detector assemblies. • Attachment of CZT radiation detectors was improved through comparative studies. • Bare detector metallization

DUMAND detector

CERN Multimedia

This object is one of the 256 other detectors of the DUMAND (Deep Underwater Muon And Neutrino Detection) experiment. The goal of the experiment was the construction of the first deep ocean high energy neutrino detector, to be placed at 4800 m depth in the Pacific Ocean off Keahole Point on the Big Island of Hawaii. A few years ago, a European conference with Cosmic experiments was organized at CERN as they were projects like DUMAND in Hawaii. Along with the conference, a temporary exhibition was organised as well. It was a collaboration of institutions from Germany, Japan, Switzerland and the U.S.A. CERN had borrowed equipment and objects from different institutes around the world, including this detector of the DUMAND experiment. Most of the equipment were sent back to the institutes, however this detector sphere was offered to a CERN member of the personnel.

Inverter ratio failure detector

Science.gov (United States)

Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

1974-01-01

A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

Multi-sensor radiation detector system

International Nuclear Information System (INIS)

Foster, R.G.; Cyboron, R.D.

1975-01-01

The invention is a multi-sensor radiation detection system including a self-powered detector and an ion or fission chamber, preferably joined as a unitary structure, for removable insertion into a nuclear reactor. The detector and chamber are connected electrically in parallel, requiring but two conductors extending out of the reactor to external electrical circuitry which includes a load impedance, a voltage source, and switch means. The switch means are employed to alternately connect the detector and chamber either with th load impedance or with the load impedance and the voltage source. In the former orientation, current through the load impedance indicates flux intensity at the self-powered detector and in the latter orientation, the current indicates flux intensity at the detector and fission chamber, though almost all of the current is contributed by the fission chamber. (auth)

The Upgraded D0 detector

Energy Technology Data Exchange (ETDEWEB)

Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, D.L.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahmed, S.N.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, J.T.; Anderson, S.; /Buenos Aires U. /Rio de Janeiro, CBPF /Sao Paulo, IFT /Alberta U.

2005-07-01

The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.

The finite element method in engineering, 2nd edition

International Nuclear Information System (INIS)

Rao, S.S.

1986-01-01

This work provides a systematic introduction to the various aspects of the finite element method as applied to engineering problems. Contents include: introduction to finite element method; solution of finite element equations; solid and structural mechanics; static analysis; dynamic analysis; heat transfer; fluid mechanics and additional applications

The 150 ns detector project: progress with small detectors

International Nuclear Information System (INIS)

Warburton, W.K.; Russell, S.R.; Kleinfelder, Stuart A.; Segal, Julie

1994-01-01

This project's long term goal is to develop a pixel area detector capable of 6 MHz frame rates (150 ns/frame). Our milestones toward this goal are: a single pixel, 1x256 1D and 8x8 2D detectors, 256x256 2D detectors and, finally, 1024x1024 2D detectors. The design strategy is to supply a complete electronics chain (resetting preamp, selectable gain amplifier, analog-to-digital converter (ADC), and memory) for each pixel. In the final detectors these will all be custom integrated circuits. The front end preamplifiers are being integrated first, since their design and performance are both the most unusual and also critical to the project's success. Similarly, our early work is also concentrating on devising and perfecting detector structures which are thick enough (1 mm) to absorb over 99% of the incident X-rays in the energy range of interest. In this paper we discuss our progress toward the 1x256 1D and 8x8 2D detectors. We have fabricated sample detectors at Stanford's Center for Integrated Systems and are preparing both to test them individually and to wirebond them to the preamplifier samples to produce our first working small 1D and 2D detectors. We will describe our solutions to the design problems associated with collecting charge in less than 30 ns from 1 mm thick pixels in high resistivity silicon. We have constructed and tested the front end of our preamplifier design using a commercial 1.2 μm CMOS technology and are moving on to produce a few channels of the complete preamplifier, including a switchable gain stage and output stage. We will discuss both the preamplifier design and our initial test results. ((orig.))

The 150 ns detector project: progress with small detectors

Energy Technology Data Exchange (ETDEWEB)

Warburton, W.K. (X-ray Instrumentation Associates, 2513 Charleston Rd, Ste 207, Mountain View, CA 94043 (United States)); Russell, S.R. (X-ray Instrumentation Associates, 2513 Charleston Rd, Ste 207, Mountain View, CA 94043 (United States)); Kleinfelder, Stuart A. (VLSI Physics, 19 Drury Lane, Berkeley, CA 94705 (United States)); Segal, Julie (Integrated Ckts Lab., Dept. of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States))

1994-09-01

This project's long term goal is to develop a pixel area detector capable of 6 MHz frame rates (150 ns/frame). Our milestones toward this goal are: a single pixel, 1x256 1D and 8x8 2D detectors, 256x256 2D detectors and, finally, 1024x1024 2D detectors. The design strategy is to supply a complete electronics chain (resetting preamp, selectable gain amplifier, analog-to-digital converter (ADC), and memory) for each pixel. In the final detectors these will all be custom integrated circuits. The front end preamplifiers are being integrated first, since their design and performance are both the most unusual and also critical to the project's success. Similarly, our early work is also concentrating on devising and perfecting detector structures which are thick enough (1 mm) to absorb over 99% of the incident X-rays in the energy range of interest. In this paper we discuss our progress toward the 1x256 1D and 8x8 2D detectors. We have fabricated sample detectors at Stanford's Center for Integrated Systems and are preparing both to test them individually and to wirebond them to the preamplifier samples to produce our first working small 1D and 2D detectors. We will describe our solutions to the design problems associated with collecting charge in less than 30 ns from 1 mm thick pixels in high resistivity silicon. We have constructed and tested the front end of our preamplifier design using a commercial 1.2 [mu]m CMOS technology and are moving on to produce a few channels of the complete preamplifier, including a switchable gain stage and output stage. We will discuss both the preamplifier design and our initial test results. ((orig.))

Stanford's big new detector

International Nuclear Information System (INIS)

Anon.

1984-01-01

A detector constructed for the Standford Linear Collider is described. It consists of a central drift chamber in the field of a surrounding superconducting solenoid. Furthermore included are a Cherenkov ring imaging detector for particle identification and a liquid argon calorimeter. (HSI).

Determination of sodium bis(2-ethylhexylsulfosuccinate (AOT surfactant with liquid chromatography: Comparative study of evaporative light scattering detector, ultraviolet detector and conductivity detector

Directory of Open Access Journals (Sweden)

Ho Ryul Ryu

2010-03-01

Full Text Available This work presents comparison of performance of ultraviolet (UV detector, conductivity detector (CD and evaporative light scattering detector (ELSD in terms of quantitative analysis of AOT (sodium bis(2-ethylhexylsulfosuccinate using liquid chromatography. The employed chromatographic condition, including an acetonitrile/water (45:55, v/v isocratic eluent system, is suitable for the three different detectors, and the figures of merits obtained by building up calibration plots are compared. The sensitivities of the detectors are in the order of ELSD ≈ CD >> UV detector. The linear range for quantification of AOT depends on the type of detector: the lower limits are in the order of UV detector (207 ㎍ mL-1 < CD (310 ㎍ mL-1 << ELSD (930 ㎍ mL-1, while the upper limits are 3720 ㎍ mL-1 for all the detectors (the maximum concentration of injected standard solution. The detection limits are 155 ㎍ mL-1 for ELSD, 78 ㎍ mL-1 for UV detector and 13 ㎍ mL-1 for CD, respectively. The figures of merit for each detector could be a guideline in choosing a detector in quantization of AOT. Furthermore, application of the chromatographic method to two commercial products is demonstrated.

Automatic treatment of multiple wound coils in 3D finite element problems including multiply connected regions

Energy Technology Data Exchange (ETDEWEB)

Leonard, P.J.; Lai, H.C.; Eastham, J.F.; Al-Akayshee, Q.H. [Univ. of Bath (United Kingdom)

1996-05-01

This paper describes an efficient scheme for incorporating multiple wire wound coils into 3D finite element models. The scheme is based on the magnetic scalar representation with an additional basis for each coil. There are no restrictions on the topology of coils with respect to ferromagnetic and conductor regions. Reduced scalar regions and cuts are automatically generated.

Adaptive Iterative Soft-Input Soft-Output Parallel Decision-Feedback Detectors for Asynchronous Coded DS-CDMA Systems

Directory of Open Access Journals (Sweden)

Zhang Wei

2005-01-01

Full Text Available The optimum and many suboptimum iterative soft-input soft-output (SISO multiuser detectors require a priori information about the multiuser system, such as the users' transmitted signature waveforms, relative delays, as well as the channel impulse response. In this paper, we employ adaptive algorithms in the SISO multiuser detector in order to avoid the need for this a priori information. First, we derive the optimum SISO parallel decision-feedback detector for asynchronous coded DS-CDMA systems. Then, we propose two adaptive versions of this SISO detector, which are based on the normalized least mean square (NLMS and recursive least squares (RLS algorithms. Our SISO adaptive detectors effectively exploit the a priori information of coded symbols, whose soft inputs are obtained from a bank of single-user decoders. Furthermore, we consider how to select practical finite feedforward and feedback filter lengths to obtain a good tradeoff between the performance and computational complexity of the receiver.

Development of the control system of the ALICE Transition Radiation Detector and of a test environment for quality-assurance of its front-end electronics

CERN Document Server

Mercado Pérez, Jorge

2008-01-01

Within this thesis, the detector control system (DCS) for the Transition Radiation Detector (TRD) of the ALICE experiment at the Large Hadron Collider has been developed. The TRD DCS is fully implemented as a detector oriented hierarchy of objects behaving as finite state machines. It controls and monitors over 65 thousand front-end electronics (FEE) units, a few hundred low voltage and one thousand high voltage channels, and other sub-systems such as cooling and gas. Commissioning of the TRD DCS took place during several runs with ALICE using cosmic events. Another part of this thesis describes the development of a test environment for large-scale production quality-assurance of over 4 thousand FEE read-out boards containing in total about 1.2 million read-out channels. The hardware and software components are described in detail. Additionally, a series of performance studies were carried out earlier including radiation tolerance tests of the TRAP chip which is the core component of the TRD FEE.

Development of the control system of the ALICE transition radiation detector and of a test environment for quality-assurance of its front-end electronics

International Nuclear Information System (INIS)

Mercado Perez, Jorge

2008-01-01

Within this thesis, the detector control system (DCS) for the Transition Radiation Detector (TRD) of the ALICE experiment at the Large Hadron Collider has been developed. The TRD DCS is fully implemented as a detector oriented hierarchy of objects behaving as finite state machines. It controls and monitors over 65 thousand front-end electronics (FEE) units, a few hundred low voltage and one thousand high voltage channels, and other sub-systems such as cooling and gas. Commissioning of the TRD DCS took place during several runs with ALICE using cosmic events. Another part of this thesis describes the development of a test environment for large-scale production quality-assurance of over 4 thousand FEE read-out boards containing in total about 1.2 million read-out channels. The hardware and software components are described in detail. Additionally, a series of performance studies were carried out earlier including radiation tolerance tests of the TRAP chip which is the core component of the TRD FEE. (orig.)

Development of the control system of the ALICE transition radiation detector and of a test environment for quality-assurance of its front-end electronics

Energy Technology Data Exchange (ETDEWEB)

Mercado Perez, Jorge

2008-11-10

Within this thesis, the detector control system (DCS) for the Transition Radiation Detector (TRD) of the ALICE experiment at the Large Hadron Collider has been developed. The TRD DCS is fully implemented as a detector oriented hierarchy of objects behaving as finite state machines. It controls and monitors over 65 thousand front-end electronics (FEE) units, a few hundred low voltage and one thousand high voltage channels, and other sub-systems such as cooling and gas. Commissioning of the TRD DCS took place during several runs with ALICE using cosmic events. Another part of this thesis describes the development of a test environment for large-scale production quality-assurance of over 4 thousand FEE read-out boards containing in total about 1.2 million read-out channels. The hardware and software components are described in detail. Additionally, a series of performance studies were carried out earlier including radiation tolerance tests of the TRAP chip which is the core component of the TRD FEE. (orig.)

Smoke detectors

International Nuclear Information System (INIS)

Bryant, J.; Howes, J.H.; Smout, D.W.S.

1979-01-01

A smoke detector is described which provides a smoke sensing detector and an indicating device and in which a radioactive substance is used in conjunction with two ionisation chambers. The system includes an outer electrode, a collector electrode and an inner electrode which is made of or supports the radioactive substance which, in this case, is 241 Am. The invention takes advantage of the fact that smoke particles can be allowed to enter freely the inner ionisation chamber. (U.K.)

ALFA Detector Control System

CERN Document Server

Oleiro Seabra, Luis Filipe; The ATLAS collaboration

2015-01-01

ALFA (Absolute Luminosity For ATLAS) is one of the sub-detectors of ATLAS (A Toroidal LHC Apparatus). The ALFA system is composed by four stations installed in the LHC tunnel 240 m away from the ATLAS interaction point. Each station has a vacuum and ventilation system, movement control and all the required electronics for signal processing. The Detector Control System (DCS) provides control and monitoring of several components and ensures the safe operation of the detector contributing to good Data Quality. This paper describes the ALFA DCS system including a detector overview, operation aspects and hardware control through a SCADA system, WinCC OA.

ALFA Detector Control System

CERN Document Server

Oleiro Seabra, Luis Filipe; The ATLAS collaboration

2015-01-01

ALFA (Absolute Luminosity For ATLAS) is one of the sub-detectors of ATLAS/LHC. The ALFA system is composed by two stations installed in the LHC tunnel 240 m away from each side of the ATLAS interaction point. Each station has a vacuum and ventilation system, movement control and all the required electronic for signal processing. The Detector Control System (DCS) provides control and monitoring of several components and ensures the safe operation of the detector contributing to good Data Quality. This paper describes the ALFA DCS system including a detector overview, operation aspects and hardware control through a SCADA system, WinCC OA.

The Mark II detector for the SLC

International Nuclear Information System (INIS)

Abrams, G.; Baden, A.R.; Boyer, J.; Butler, F.; Drell, P.S.; Fay, J.; Gidal, G.; Goldhaber, G.; Haggerty, J.; Harr, R.; Hearty, C.; Herrup, D.; Holmgren, S.O.; Jaffre, M.; Juricic, I.; Kadyk, J.A.; Kral, J.F.; Levi, M.E.; Lynch, G.R.; Richman, J.D.; Rouse, F.R.; Schaad, M.W.; Schmidke, W.B.; Schumm, B.A.; Trilling, G.H.; Wood, D.R.; Akerlof, C.; Bonvicini, G.; Chapman, J.; Chmeissani, M.; Frey, R.; Gero, E.; Hong, S.J.; Koska, W.; Nitz, D.; Petradza, M.; Thun, R.; Tschirhart, R.; Veltman, H.; Alexander, J.P.; Ballam, J.; Barklow, T.; Bartelt, J.; De Boer, W.; Boyarski, A.; Braune, K.; Bulos, F.; Burke, D.L.; Cords, D.; Coupal, D.P.; Destaebler, H.C.; Dorfan, J.M.; Feldman, G.J.; Fernandes, D.; Field, R.C.; Fordham, C.; Fujino, D.; Gan, K.K.; Glanzman, T.; Grosse-Wiesmann, P.; Hanson, G.; Hayes, K.; Himel, T.; Hutchinson, D.; Innes, W.R.; Jacobsen, R.G.; Jaros, J.A.; Jung, C.K.; Karlen, D.; Klein, S.R.; Koetke, D.; Komamiya, M.; Kowalski, L.A.; Kozanecki, W.; Lankford, A.J.; Larsen, R.R.; Lueth, V.; Mattison, T.; Moffeit, K.C.; Mueller, L.; Munger, C.T.; Nash, J.; Ong, R.A.; O'Shaughnessy, K.F.; Perl, J.; Perl, M.L.; Perrier, F.; Petersen, A.; Pitthan, R.; Riles, K.; Swartz, M.; Taylor, R.E.; Van Kooten, R.; Voruganti, P.; Weigend, A.; Woods, M.; Wormser, G.; Wright, R.; Alvarez, M.; Calvino, F.; Fernandez, E.; Ford, W.T.; Hinshaw, D.A.; Rankin, P.; Smith, J.G.; Wagner, S.R.; Weber, P.; White, S.L.; Averill, D.; Blockus, D.; Brabson, B.; Brom, J.M.; Murray, W.N.; Ogren, H.; Rust, D.R.; Snyder, A.; Yurko, M.; Barish, B.C.; Hawkes, C.M.; Hoenk, M.; Kuhlen, M.; Li, Z.; McKenna, J.A.; Milliken, B.D.; Nelson, M.E.; Peck, C.; Porter, F.C.; Soderstrom, E.; Stroynowski, R.; Weinstein, A.J.; Weir, A.J.; Wicklund, E.; Wolf, R.C.; Wu, D.Y.; Barnett, B.A.; Boswell, C.; Dauncey, P.; Drewer, D.C.; Harral, B.; Hylen, J.; Matthews, J.A.J.; Stoker, D.P.; Vejcik, S.; Breakstone, A.; Cence, R.J.; Gong, X.; Harris, F.A.; Koide, A.; Parker, S.I.; Green, A.; Lawrence Berkeley Lab., CA; California Univ., Berkeley

1989-01-01

The Mark II detector has been upgraded in preparation for its role as the first detector to take data at the Stanford Linear Collider. The new detector components include the central drift chamber, the time-of-flight system, the coil, the endcap electromagnetic calorimeters and the beam energy and luminosity measuring devices. There have also been improvements in detector hermeticity. All of the major components were installed for a test run at the PEP storage ring (√s=29 GeV) in 1985. This paper describes the upgraded detector, including its trigger and data acquisition systems, and gives performance figures for its components. Future improvements are also discussed. (orig.)

Nonlinear finite element modeling of corrugated board

Science.gov (United States)

A. C. Gilchrist; J. C. Suhling; T. J. Urbanik

1999-01-01

In this research, an investigation on the mechanical behavior of corrugated board has been performed using finite element analysis. Numerical finite element models for corrugated board geometries have been created and executed. Both geometric (large deformation) and material nonlinearities were included in the models. The analyses were performed using the commercial...

Programming the finite element method

CERN Document Server

Smith, I M; Margetts, L

2013-01-01

Many students, engineers, scientists and researchers have benefited from the practical, programming-oriented style of the previous editions of Programming the Finite Element Method, learning how to develop computer programs to solve specific engineering problems using the finite element method. This new fifth edition offers timely revisions that include programs and subroutine libraries fully updated to Fortran 2003, which are freely available online, and provides updated material on advances in parallel computing, thermal stress analysis, plasticity return algorithms, convection boundary c

Finite Volumes for Complex Applications VII

CERN Document Server

Ohlberger, Mario; Rohde, Christian

2014-01-01

The methods considered in the 7th conference on "Finite Volumes for Complex Applications" (Berlin, June 2014) have properties which offer distinct advantages for a number of applications. The second volume of the proceedings covers reviewed contributions reporting successful applications in the fields of fluid dynamics, magnetohydrodynamics, structural analysis, nuclear physics, semiconductor theory and other topics. The finite volume method in its various forms is a space discretization technique for partial differential equations based on the fundamental physical principle of conservation. Recent decades have brought significant success in the theoretical understanding of the method. Many finite volume methods preserve further qualitative or asymptotic properties, including maximum principles, dissipativity, monotone decay of free energy, and asymptotic stability. Due to these properties, finite volume methods belong to the wider class of compatible discretization methods, which preserve qualitative propert...

Simulated and experimental spectroscopic performance of GaAs X-ray pixel detectors

International Nuclear Information System (INIS)

Bisogni, M.G.; Cola, A.; Fantacci, M.E.

2001-01-01

In pixel detectors, the electrode geometry affects the signal shape and therefore the spectroscopic performance of the device. This effect is enhanced in semiconductors where carrier trapping is relevant. In particular, semi insulating (SI) GaAs crystals present an incomplete charge collection due to a high concentration of deep traps in the bulk. In the last few years, SI GaAs pixel detectors have been developed as soft X-ray detectors for medical imaging applications. In this paper, we present a numerical method to evaluate the local charge collection properties of pixel detectors. A bi-dimensional description has been used to represent the detector geometry. According to recent models, the active region of a reverse biased SI GaAs detector is almost neutral. Therefore, the electrostatic potential inside a full active detector has been evaluated using the Laplace equation. A finite difference method with a fixed step orthogonal mesh has been adopted. The photon interaction point has been generated with a Monte Carlo method according to the attenuation length of a monochromatic X-ray beam in GaAs. The number of photogenerated carriers for each interaction has been extracted using a gaussian distribution. The induced signal on the collecting electrode has been calculated according to the Ramo's theorem and the trapping effect has been modeled introducing electron and hole lifetimes. The noise of the charge preamplifier have been also taken into account. A comparison between simulated and experimental X-ray spectra from a 241 Am source acquired with different GaAs pixel detectors has been carried out

New Multigrid Method Including Elimination Algolithm Based on High-Order Vector Finite Elements in Three Dimensional Magnetostatic Field Analysis

Science.gov (United States)

Hano, Mitsuo; Hotta, Masashi

A new multigrid method based on high-order vector finite elements is proposed in this paper. Low level discretizations in this method are obtained by using low-order vector finite elements for the same mesh. Gauss-Seidel method is used as a smoother, and a linear equation of lowest level is solved by ICCG method. But it is often found that multigrid solutions do not converge into ICCG solutions. An elimination algolithm of constant term using a null space of the coefficient matrix is also described. In three dimensional magnetostatic field analysis, convergence time and number of iteration of this multigrid method are discussed with the convectional ICCG method.

Pulse-height loss in the signal readout circuit of compound semiconductor detectors

Science.gov (United States)

Nakhostin, M.; Hitomi, K.

2018-06-01

Compound semiconductor detectors such as CdTe, CdZnTe, HgI2 and TlBr are known to exhibit large variations in their charge collection times. This paper considers the effect of such variations on the measurement of induced charge pulses by using resistive feedback charge-sensitive preamplifiers. It is shown that, due to the finite decay-time constant of the preamplifiers, the capacitive decay during the signal readout leads to a variable deficit in the measurement of ballistic signals and a digital pulse processing method is employed to correct for it. The method is experimentally examined by using sampled pulses from a TlBr detector coupled to a charge-sensitive preamplifier with 150 μs of decay-time constant and 20 % improvement in the energy resolution of the detector at 662 keV is achieved. The implications of the capacitive decay on the correction of charge-trapping effect by using depth-sensing technique are also considered.

Construction of the CDF silicon vertex detector

International Nuclear Information System (INIS)

Skarha, J.; Barnett, B.; Boswell, C.; Snider, F.; Spies, A.; Tseng, J.; Vejcik, S.; Carter, H.; Flaugher, B.; Gonzales, B.; Hrycyk, M.; Nelson, C.; Segler, S.; Shaw, T.; Tkaczyk, S.; Turner, K.; Wesson, T.; Carithers, W.; Ely, R.; Haber, C.; Holland, S.; Kleinfelder, S.; Merrick, T.; Schneider, O.; Wester, W.; Wong, M.; Amidei, D.; Derwent, P.; Gold, M.; Matthews, J.; Bacchetta, N.; Bisello, D.; Busetto, G.; Castro, A.; Loreti, M.; Pescara, L.; Bedeschi, F.; Bolognesi, V.; Dell'Agnello, S.; Galeotti, S.; Mariotti, M.; Menzione, A.; Punzi, G.; Raffaelli, F.; Risotri, L.; Tartarelli, F.; Turini, N.; Wenzel, H.; Zetti, F.; Bailey, M.; Garfinkel, A.; Shaw, N.; Tipton, P.; Watts, G.

1992-04-01

Technical details and methods used in constructing the CDF silicon vertex detector are presented. This description includes a discussion of the foam-carbon fiber composite structure used to silicon microstrip detectors and the procedure for achievement of 5 μm detector alignment. The construction of the beryllium barrel structure, which houses the detector assemblies, is also described. In addition, the 10 μm placement accuracy of the detectors in the barrel structure is discussed and the detector cooling and mounting systems are described. 12 refs

SoLid Detector Technology

Science.gov (United States)

Labare, Mathieu

2017-09-01

SoLid is a reactor anti-neutrino experiment where a novel detector is deployed at a minimum distance of 5.5 m from a nuclear reactor core. The purpose of the experiment is three-fold: to search for neutrino oscillations at a very short baseline; to measure the pure 235U neutrino energy spectrum; and to demonstrate the feasibility of neutrino detectors for reactor monitoring. This report presents the unique features of the SoLid detector technology. The technology has been optimised for a high background environment resulting from low overburden and the vicinity of a nuclear reactor. The versatility of the detector technology is demonstrated with a 288 kg detector prototype which was deployed at the BR2 nuclear reactor in 2015. The data presented includes both reactor on, reactor off and calibration measurements. The measurement results are compared with Monte Carlo simulations. The 1.6t SoLid detector is currently under construction, with an optimised design and upgraded material technology to enhance the detector capabilities. Its deployement on site is planned for the begin of 2017 and offers the prospect to resolve the reactor anomaly within about two years.

Summary of activity. Topic I: detectors and experiments

International Nuclear Information System (INIS)

Marx, J.; Ozaki, S.

Results of a workshop studying detectors for Isabelle experimental halls are described. The detectors must be very reliable. Spatial resolution of the tracking detectors must be high to provide accurate measurements of angle and momentum, retain a short resolving time, and show excellent multiparticle handling capability. Included in the study were hodoscopes, drift chambers, proportional chambers, time projection chambers, Cherenkov counters, electromagnetic shower detectors, and hadron calorimeters. Data handling methods were also included in the studies

Optimization of powered Stirling heat engine with finite speed thermodynamics

International Nuclear Information System (INIS)

Ahmadi, Mohammad H.; Ahmadi, Mohammad Ali; Pourfayaz, Fathollah; Bidi, Mokhtar; Hosseinzade, Hadi; Feidt, Michel

2016-01-01

Highlights: • Based on finite speed method and direct method, the optimal performance is investigated. • The effects of major parameters on the optimal performance are investigated. • The accuracy of the results was compared with previous works. - Abstract: Popular thermodynamic analyses including finite time thermodynamic analysis was lately developed based upon external irreversibilities while internal irreversibilities such as friction, pressure drop and entropy generation were not considered. The aforementioned disadvantage reduces the reliability of the finite time thermodynamic analysis in the design of an accurate Stirling engine model. Consequently, the finite time thermodynamic analysis could not sufficiently satisfy researchers for implementing in design and optimization issues. In this study, finite speed thermodynamic analysis was employed instead of finite time thermodynamic analysis for studying Stirling heat engine. The finite speed thermodynamic analysis approach is based on the first law of thermodynamics for a closed system with finite speed and the direct method. The effects of heat source temperature, regenerating effectiveness, volumetric ratio, piston stroke as well as rotational speed are included in the analysis. Moreover, maximum output power in optimal rotational speed was calculated while pressure losses in the Stirling engine were systematically considered. The result reveals the accuracy and the reliability of the finite speed thermodynamic method in thermodynamic analysis of Stirling heat engine. The outcomes can help researchers in the design of an appropriate and efficient Stirling engine.

ATLAS Pixel Detector Operational Experience

CERN Document Server

Di Girolamo, B; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.9% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Current technology of particle physics detectors

International Nuclear Information System (INIS)

Ludlam, T.W.

1986-01-01

A brief discussion is given of the characteristics required of new accelerator facilities, leading into a discussion of the required detectors, including position sensitive detectors, particle identification, and calorimeters

Comparison of Detector Technologies for CAPS

Science.gov (United States)

Stockum, Jana L.

2005-01-01

In this paper, several different detectors are examined for use in a Comet/Asteroid Protection System (CAPS), a conceptual study for a possible future space-based system. Each detector will be examined for its future (25 years or more in the future) ability to find and track near-Earth Objects (NEOs) from a space-based detection platform. Within the CAPS study are several teams of people who each focus on different aspects of the system concept. This study s focus is on detection devices. In particular, evaluations on the following devices have been made: charge-coupled devices (CCDs), charge-injected devices (CIDs), superconducting tunneling junctions (STJs), and transition edge sensors (TESs). These devices can be separated into two main categories; the first category includes detectors that are currently being widely utilized, such as CCDs and CIDs. The second category includes experimental detectors, such as STJs and TESs. After the discussion of the detectors themselves, there will be a section devoted to the explicit use of these detectors with CAPS.

Small Pixel Hybrid CMOS X-ray Detectors

Science.gov (United States)

Hull, Samuel; Bray, Evan; Burrows, David N.; Chattopadhyay, Tanmoy; Falcone, Abraham; Kern, Matthew; McQuaide, Maria; Wages, Mitchell

2018-01-01

Concepts for future space-based X-ray observatories call for a large effective area and high angular resolution instrument to enable precision X-ray astronomy at high redshift and low luminosity. Hybrid CMOS detectors are well suited for such high throughput instruments, and the Penn State X-ray detector lab, in collaboration with Teledyne Imaging Sensors, has recently developed new small pixel hybrid CMOS X-ray detectors. These prototype 128x128 pixel devices have 12.5 micron pixel pitch, 200 micron fully depleted depth, and include crosstalk eliminating CTIA amplifiers and in-pixel correlated double sampling (CDS) capability. We report on characteristics of these new detectors, including the best read noise ever measured for an X-ray hybrid CMOS detector, 5.67 e- (RMS).

The finite-difference and finite-element modeling of seismic wave propagation and earthquake motion

International Nuclear Information System (INIS)

Moczo, P.; Kristek, J.; Pazak, P.; Balazovjech, M.; Moczo, P.; Kristek, J.; Galis, M.

2007-01-01

Numerical modeling of seismic wave propagation and earthquake motion is an irreplaceable tool in investigation of the Earth's structure, processes in the Earth, and particularly earthquake phenomena. Among various numerical methods, the finite-difference method is the dominant method in the modeling of earthquake motion. Moreover, it is becoming more important in the seismic exploration and structural modeling. At the same time we are convinced that the best time of the finite-difference method in seismology is in the future. This monograph provides tutorial and detailed introduction to the application of the finite difference (FD), finite-element (FE), and hybrid FD-FE methods to the modeling of seismic wave propagation and earthquake motion. The text does not cover all topics and aspects of the methods. We focus on those to which we have contributed. We present alternative formulations of equation of motion for a smooth elastic continuum. We then develop alternative formulations for a canonical problem with a welded material interface and free surface. We continue with a model of an earthquake source. We complete the general theoretical introduction by a chapter on the constitutive laws for elastic and viscoelastic media, and brief review of strong formulations of the equation of motion. What follows is a block of chapters on the finite-difference and finite-element methods. We develop FD targets for the free surface and welded material interface. We then present various FD schemes for a smooth continuum, free surface, and welded interface. We focus on the staggered-grid and mainly optimally-accurate FD schemes. We also present alternative formulations of the FE method. We include the FD and FE implementations of the traction-at-split-nodes method for simulation of dynamic rupture propagation. The FD modeling is applied to the model of the deep sedimentary Grenoble basin, France. The FD and FE methods are combined in the hybrid FD-FE method. The hybrid

Finite Element Methods and Their Applications

CERN Document Server

Chen, Zhangxin

2005-01-01

This book serves as a text for one- or two-semester courses for upper-level undergraduates and beginning graduate students and as a professional reference for people who want to solve partial differential equations (PDEs) using finite element methods. The author has attempted to introduce every concept in the simplest possible setting and maintain a level of treatment that is as rigorous as possible without being unnecessarily abstract. Quite a lot of attention is given to discontinuous finite elements, characteristic finite elements, and to the applications in fluid and solid mechanics including applications to porous media flow, and applications to semiconductor modeling. An extensive set of exercises and references in each chapter are provided.

Quantum channels with a finite memory

International Nuclear Information System (INIS)

Bowen, Garry; Mancini, Stefano

2004-01-01

In this paper we study quantum communication channels with correlated noise effects, i.e., quantum channels with memory. We derive a model for correlated noise channels that includes a channel memory state. We examine the case where the memory is finite, and derive bounds on the classical and quantum capacities. For the entanglement-assisted and unassisted classical capacities it is shown that these bounds are attainable for certain classes of channel. Also, we show that the structure of any finite-memory state is unimportant in the asymptotic limit, and specifically, for a perfect finite-memory channel where no information is lost to the environment, achieving the upper bound implies that the channel is asymptotically noiseless

Neutron detector development at Brookhaven

International Nuclear Information System (INIS)

Yu, B.; Harder, J.A.; Mead, J.A.; Radeka, V.; Schaknowski, N.A.; Smith, G.C.

2003-01-01

Two-dimensional thermal neutron detectors have been the subject of research and development at Brookhaven for over 20 years. Based primarily on multi-wire chambers filled with a gas mixture containing 3 He, these detectors have been used in wide-ranging studies of molecular biology and material science samples. At each phase of development, experimenters have sought improvements in key parameters such as position resolution, counting rate, efficiency, solid-angle coverage and stability. A suite of detectors has been developed with sensitive areas ranging from 5x5 to 50x50 cm 2 . These devices incorporate low-noise-position readout and the best position resolution for thermal neutron gas detectors. Recent developments include a 1.5 mx20 cm detector containing multiple segments with continuously sensitive readout, and detectors with unity gain for ultra-high rate capability and long-term stability

Bibliography for finite elements. [2200 references

Energy Technology Data Exchange (ETDEWEB)

Whiteman, J R [comp.

1975-01-01

This bibliography cites almost all of the significant papers on advances in the mathematical theory of finite elements. Reported are applications in aeronautical, civil, mechanical, nautical and nuclear engineering. Such topics as classical analysis, functional analysis, approximation theory, fluids, and diffusion are covered. Over 2200 references to publications up to the end of 1974 are included. Publications are listed alphabetically by author and also by keywords. In addition, finite element packages are listed.

An efficient finite element solution for gear dynamics

International Nuclear Information System (INIS)

Cooley, C G; Parker, R G; Vijayakar, S M

2010-01-01

A finite element formulation for the dynamic response of gear pairs is proposed. Following an established approach in lumped parameter gear dynamic models, the static solution is used as the excitation in a frequency domain solution of the finite element vibration model. The nonlinear finite element/contact mechanics formulation provides accurate calculation of the static solution and average mesh stiffness that are used in the dynamic simulation. The frequency domain finite element calculation of dynamic response compares well with numerically integrated (time domain) finite element dynamic results and previously published experimental results. Simulation time with the proposed formulation is two orders of magnitude lower than numerically integrated dynamic results. This formulation admits system level dynamic gearbox response, which may include multiple gear meshes, flexible shafts, rolling element bearings, housing structures, and other deformable components.

Socio-economic applications of finite state mean field games

KAUST Repository

Gomes, Diogo A.; Machado Velho, Roberto; Wolfram, Marie Therese

2014-01-01

In this paper, we present different applications of finite state mean field games to socio-economic sciences. Examples include paradigm shifts in the scientific community or consumer choice behaviour in the free market. The corresponding finite

Finite Larmor radius stabilization of ballooning modes in tokamaks

International Nuclear Information System (INIS)

Tsang, K.T.

1980-07-01

A ballooning mode equation that includes full finite Larmor radius effects has been derived from the Vlasov equation for a circular tokamak equilibrium. Numerical solution of this equation shows that finite Larmor radius effects are stabilizing

A novel muon detector for borehole density tomography

Science.gov (United States)

Bonneville, Alain; Kouzes, Richard T.; Yamaoka, Jared; Rowe, Charlotte; Guardincerri, Elena; Durham, J. Matthew; Morris, Christopher L.; Poulson, Daniel C.; Plaud-Ramos, Kenie; Morley, Deborah J.; Bacon, Jeffrey D.; Bynes, James; Cercillieux, Julien; Ketter, Chris; Le, Khanh; Mostafanezhad, Isar; Varner, Gary; Flygare, Joshua; Lintereur, Azaree T.

2017-04-01

Muons can be used to image the density of materials through which they pass, including geological structures. Subsurface applications of the technology include tracking fluid migration during injection or production, with increasing concern regarding such timely issues as induced seismicity or chemical leakage into aquifers. Current density monitoring options include gravimetric data collection and active or passive seismic surveys. One alternative, or complement, to these methods is the development of a muon detector that is sufficiently compact and robust for deployment in a borehole. Such a muon detector can enable imaging of density structure to monitor small changes in density - a proxy for fluid migration - at depths up to 1500 m. Such a detector has been developed, and Monte Carlo modeling methods applied to simulate the anticipated detector response. Testing and measurements using a prototype detector in the laboratory and shallow underground laboratory demonstrated robust response. A satisfactory comparison with a large drift tube-based muon detector is also presented.

18th International Workshop on Radiation Imaging Detectors

CERN Document Server

2016-01-01

The International Workshops on Radiation Imaging Detectors are held yearly and provide an international forum for discussing current research and developments in the area of position sensitive detectors for radiation imaging, including semiconductor detectors, gas and scintillator-based detectors. Topics include processing and characterization of detector materials, hybridization and interconnect technologies, design of counting or integrating electronics, readout and data acquisition systems, and applications in various scientific and industrial fields. The workshop will have plenary sessions with invited and contributed papers presented orally and in poster sessions. The invited talks will be chosen to review recent advances in different areas covered in the workshop.

Semiconductor X-ray detectors

CERN Document Server

Lowe, Barrie Glyn

2014-01-01

Identifying and measuring the elemental x-rays released when materials are examined with particles (electrons, protons, alpha particles, etc.) or photons (x-rays and gamma rays) is still considered to be the primary analytical technique for routine and non-destructive materials analysis. The Lithium Drifted Silicon (Si(Li)) X-Ray Detector, with its good resolution and peak to background, pioneered this type of analysis on electron microscopes, x-ray fluorescence instruments, and radioactive source- and accelerator-based excitation systems. Although rapid progress in Silicon Drift Detectors (SDDs), Charge Coupled Devices (CCDs), and Compound Semiconductor Detectors, including renewed interest in alternative materials such as CdZnTe and diamond, has made the Si(Li) X-Ray Detector nearly obsolete, the device serves as a useful benchmark and still is used in special instances where its large, sensitive depth is essential. Semiconductor X-Ray Detectors focuses on the history and development of Si(Li) X-Ray Detect...

Thomas Fermi model of finite nuclei

International Nuclear Information System (INIS)

Boguta, J.; Rafelski, J.

1977-01-01

A relativistic Thomas-Fermi model of finite-nuclei is considered. The effective nuclear interaction is mediated by exchanges of isoscalar scalar and vector mesons. The authors include also a self-interaction of the scalar meson field and the Coulomb repulsion of the protons. The parameters of the model are constrained by the average nuclear properties. The Thomas-Fermi equations are solved numerically for finite, stable nuclei. The particular case of 208 82 Pb is considered in more detail. (Auth.)

Comparisons between simulation and measurements taken with the Medipix3RX detector

Science.gov (United States)

McGrath, J.; Marchal, J.; Plackett, R.; Horswell, I.; Omar, D.; Gimenez, E. N.; Tartoni, N.

2014-05-01

A simulation toolkit developed for use at Diamond Light Source is presented, accompanied with experimental validation using a silicon pixel-array sensor coupled to a Medipix3RX chip controlled via the Merlin Readout System. The simulation makes use of Geant4, where photons are tracked in order to determine their position of interaction and energy deposition. Further to this, a Finite Element Methods package, Comsol, is used to model the Charge Induction Efficiencies of various sensors. Results are coupled to Geant4 simulations to provide an accurate method for computing the signals generated on each pixel within the sensor and then an algorithm to model the front-end electronics of the device. The validity of the simulation toolkit is tested by investigating charge-sharing effects using a Medipix3RX chip bump-bonded to a silicon pixel-array sensor. The dependence of the imaging parameters, on the energy threshold, is presented from both simulation and experiment for the Medipix3RX chip operated with and without the charge sharing compensation circuitry enabled. This simulation toolkit can be used to calculate image quality parameters for the next generation of detectors, including CdTe, as well as to improve data corrections on existing detectors on synchrotron beamlines.

Comparisons between simulation and measurements taken with the Medipix3RX detector

International Nuclear Information System (INIS)

McGrath, J; Marchal, J; Plackett, R; Horswell, I; Omar, D; Gimenez, E N; Tartoni, N

2014-01-01

A simulation toolkit developed for use at Diamond Light Source is presented, accompanied with experimental validation using a silicon pixel-array sensor coupled to a Medipix3RX chip controlled via the Merlin Readout System. The simulation makes use of Geant4, where photons are tracked in order to determine their position of interaction and energy deposition. Further to this, a Finite Element Methods package, Comsol, is used to model the Charge Induction Efficiencies of various sensors. Results are coupled to Geant4 simulations to provide an accurate method for computing the signals generated on each pixel within the sensor and then an algorithm to model the front-end electronics of the device. The validity of the simulation toolkit is tested by investigating charge-sharing effects using a Medipix3RX chip bump-bonded to a silicon pixel-array sensor. The dependence of the imaging parameters, on the energy threshold, is presented from both simulation and experiment for the Medipix3RX chip operated with and without the charge sharing compensation circuitry enabled. This simulation toolkit can be used to calculate image quality parameters for the next generation of detectors, including CdTe, as well as to improve data corrections on existing detectors on synchrotron beamlines

DWBA (d,N) Calculations Including Dirac Phenomenological Potentials and an Exact Treatment of Finite-range Effects

Science.gov (United States)

Hawk, Eric

2005-04-01

An algorithm for the inclusion of both Dirac phenomenological potentials and an exact treatment of finite-range effects within the DWBA is presented. The numerical implementation of this algorithm is used to calculate low-energy deuteron stripping cross sections, analyzing powers, and polarizations. These calculations are compared with experimental data where available. The impact of using several commonly employed nuclear potentials (Reid soft-core, Bonn, Argonne v18) for the internal deuteron wave function is also examined.

Radiation detectors

International Nuclear Information System (INIS)

2013-01-01

This sixth chapter presents the operational principles of the radiation detectors; detection using photographic emulsions; thermoluminescent detectors; gas detectors; scintillation detectors; liquid scintillation detectors; detectors using semiconductor materials; calibration of detectors; Bragg-Gray theory; measurement chain and uncertainties associated to measurements

Electromechanically cooled germanium radiation detector system

International Nuclear Information System (INIS)

Lavietes, Anthony D.; Joseph Mauger, G.; Anderson, Eric H.

1999-01-01

We have successfully developed and fielded an electromechanically cooled germanium radiation detector (EMC-HPGe) at Lawrence Livermore National Laboratory (LLNL). This detector system was designed to provide optimum energy resolution, long lifetime, and extremely reliable operation for unattended and portable applications. For most analytical applications, high purity germanium (HPGe) detectors are the standard detectors of choice, providing an unsurpassed combination of high energy resolution performance and exceptional detection efficiency. Logistical difficulties associated with providing the required liquid nitrogen (LN) for cooling is the primary reason that these systems are found mainly in laboratories. The EMC-HPGe detector system described in this paper successfully provides HPGe detector performance in a portable instrument that allows for isotopic analysis in the field. It incorporates a unique active vibration control system that allows the use of a Sunpower Stirling cycle cryocooler unit without significant spectral degradation from microphonics. All standard isotopic analysis codes, including MGA and MGA++, GAMANL, GRPANL and MGAU, typically used with HPGe detectors can be used with this system with excellent results. Several national and international Safeguards organisations including the International Atomic Energy Agency (IAEA) and U.S. Department of Energy (DOE) have expressed interest in this system. The detector was combined with custom software and demonstrated as a rapid Field Radiometric Identification System (FRIS) for the U.S. Customs Service . The European Communities' Safeguards Directorate (EURATOM) is field-testing the first Safeguards prototype in their applications. The EMC-HPGe detector system design, recent applications, and results will be highlighted

The PHOBOS detector at RHIC

Science.gov (United States)

Back, B. B.; Baker, M. D.; Barton, D. S.; Basilev, S.; Baum, R.; Betts, R. R.; Białas, A.; Bindel, R.; Bogucki, W.; Budzanowski, A.; Busza, W.; Carroll, A.; Ceglia, M.; Chang, Y.-H.; Chen, A. E.; Coghen, T.; Connor, C.; Czyż, W.; Dabrowski, B.; Decowski, M. P.; Despet, M.; Fita, P.; Fitch, J.; Friedl, M.; Gałuszka, K.; Ganz, R.; Garcia, E.; George, N.; Godlewski, J.; Gomes, C.; Griesmayer, E.; Gulbrandsen, K.; Gushue, S.; Halik, J.; Halliwell, C.; Haridas, P.; Hayes, A.; Heintzelman, G. A.; Henderson, C.; Hollis, R.; Hołyński, R.; Hofman, D.; Holzman, B.; Johnson, E.; Kane, J.; Katzy, J.; Kita, W.; Kotuła, J.; Kraner, H.; Kucewicz, W.; Kulinich, P.; Law, C.; Lemler, M.; Ligocki, J.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Neal, M.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Patel, M.; Pernegger, H.; Plesko, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Ross, D.; Rosenberg, L.; Ryan, J.; Sanzgiri, A.; Sarin, P.; Sawicki, P.; Scaduto, J.; Shea, J.; Sinacore, J.; Skulski, W.; Steadman, S. G.; Stephans, G. S. F.; Steinberg, P.; Straczek, A.; Stodulski, M.; Strek, M.; Stopa, Z.; Sukhanov, A.; Surowiecka, K.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Zalewski, K.; Żychowski, P.; Phobos Collaboration

2003-03-01

This manuscript contains a detailed description of the PHOBOS experiment as it is configured for the Year 2001 running period. It is capable of detecting charged particles over the full solid angle using a multiplicity detector and measuring identified charged particles near mid-rapidity in two spectrometer arms with opposite magnetic fields. Both of these components utilize silicon pad detectors for charged particle detection. The minimization of material between the collision vertex and the first layers of silicon detectors allows for the detection of charged particles with very low transverse momenta, which is a unique feature of the PHOBOS experiment. Additional detectors include a time-of-flight wall which extends the particle identification range for one spectrometer arm, as well as sets of scintillator paddle and Cherenkov detector arrays for event triggering and centrality selection.

Preservation theorems on finite structures

International Nuclear Information System (INIS)

Hebert, M.

1994-09-01

This paper concerns classical Preservation results applied to finite structures. We consider binary relations for which a strong form of preservation theorem (called strong interpolation) exists in the usual case. This includes most classical cases: embeddings, extensions, homomorphisms into and onto, sandwiches, etc. We establish necessary and sufficient syntactic conditions for the preservation theorems for sentences and for theories to hold in the restricted context of finite structures. We deduce that for all relations above, the restricted theorem for theories hold provided the language is finite. For the sentences the restricted version fails in most cases; in fact the ''homomorphism into'' case seems to be the only possible one, but the efforts to show that have failed. We hope our results may help to solve this frustrating problem; in the meantime, they are used to put a lower bound on the level of complexity of potential counterexamples. (author). 8 refs

Imaging x-ray sources at a finite distance in coded-mask instruments

International Nuclear Information System (INIS)

Donnarumma, Immacolata; Pacciani, Luigi; Lapshov, Igor; Evangelista, Yuri

2008-01-01

We present a method for the correction of beam divergence in finite distance sources imaging through coded-mask instruments. We discuss the defocusing artifacts induced by the finite distance showing two different approaches to remove such spurious effects. We applied our method to one-dimensional (1D) coded-mask systems, although it is also applicable in two-dimensional systems. We provide a detailed mathematical description of the adopted method and of the systematics introduced in the reconstructed image (e.g., the fraction of source flux collected in the reconstructed peak counts). The accuracy of this method was tested by simulating pointlike and extended sources at a finite distance with the instrumental setup of the SuperAGILE experiment, the 1D coded-mask x-ray imager onboard the AGILE (Astro-rivelatore Gamma a Immagini Leggero) mission. We obtained reconstructed images of good quality and high source location accuracy. Finally we show the results obtained by applying this method to real data collected during the calibration campaign of SuperAGILE. Our method was demonstrated to be a powerful tool to investigate the imaging response of the experiment, particularly the absorption due to the materials intercepting the line of sight of the instrument and the conversion between detector pixel and sky direction

Finite elements for analysis and design

CERN Document Server

Akin, J E; Davenport, J H

1994-01-01

The finite element method (FEM) is an analysis tool for problem-solving used throughout applied mathematics, engineering, and scientific computing. Finite Elements for Analysis and Design provides a thoroughlyrevised and up-to-date account of this important tool and its numerous applications, with added emphasis on basic theory. Numerous worked examples are included to illustrate the material.Key Features* Akin clearly explains the FEM, a numerical analysis tool for problem-solving throughout applied mathematics, engineering and scientific computing* Basic theory has bee

The simulation of charge sharing in semiconductor X-ray pixel detectors

CERN Document Server

Mathieson, K; O'Shea, V; Passmore, M S; Rahman, M; Smith, K M; Watt, J; Whitehill, C

2002-01-01

Two simulation packages were used to model the sharing of charge, due to the scattering and diffusion of carriers, between adjacent pixel elements in semiconductors X-ray detectors. The X-ray interaction and the consequent multiple scattering was modelled with the aid of the Monte Carlo package, MCNP. The resultant deposited charge distribution was then used to create the charge cloud profile in the finite element semiconductor simulation code MEDICI. The analysis of the current pulses induced on pixel electrodes for varying photon energies was performed for a GaAs pixel detector. For a pixel pitch of 25 mu m, the charge lost to a neighbouring pixel was observed to be constant, at 0.6%, through the energies simulated. Ultimately, a fundamental limit on the pixel element size for imaging and spectroscopic devices may be set due to these key physical principles.

8th conference on Finite Volumes for Complex Applications

CERN Document Server

Omnes, Pascal

2017-01-01

This first volume of the proceedings of the 8th conference on "Finite Volumes for Complex Applications" (Lille, June 2017) covers various topics including convergence and stability analysis, as well as investigations of these methods from the point of view of compatibility with physical principles. It collects together the focused invited papers comparing advanced numerical methods for Stokes and Navier–Stokes equations on a benchmark, as well as reviewed contributions from internationally leading researchers in the field of analysis of finite volume and related methods, offering a comprehensive overview of the state of the art in the field. The finite volume method in its various forms is a space discretization technique for partial differential equations based on the fundamental physical principle of conservation, and recent decades have brought significant advances in the theoretical understanding of the method. Many finite volume methods preserve further qualitative or asymptotic properties, including m...

Detector response artefacts in spectral reconstruction

DEFF Research Database (Denmark)

Olsen, Ulrik Lund; Christensen, Erik D.; Khalil, Mohamad

2017-01-01

Energy resolved detectors are gaining traction as a tool to achieve better material contrast. K-edge imaging and tomography is an example of a method with high potential that has evolved on the capabilities of photon counting energy dispersive detectors. Border security is also beginning to see...... instruments taking advantage of energy resolved detectors. The progress of the field is halted by the limitations of the detectors. The limitations include nonlinear response for both x-ray intensity and x-ray spectrum. In this work we investigate how the physical interactions in the energy dispersive...

FERMILAB: Collider detectors -2

International Nuclear Information System (INIS)

Anon.

1993-01-01

Last month's edition (April, page 12) included a status report on data collection and preliminary physics results from the 'newcomer' DO detector at Fermilab's Tevatron proton-antiproton collider. This time the spotlight falls in the Veteran' CDF detector, in action since 1985 and meanwhile significantly upgraded. Meanwhile the Tevatron collider continues to improve, with record collision rates

Ionization detector

International Nuclear Information System (INIS)

Steele, D.S.

1987-01-01

An ionization detector having an array of detectors has, for example, grounding pads positioned in the spaces between some detectors (data detectors) and other detectors (reference detectors). The grounding pads are kept at zero electric potential, i.e. grounded. The grounding serves to drain away electrons and thereby prevent an unwanted accumulation of charge in the spaces, and cause the electric field lines to be more perpendicular to the detectors in regions near the grounding pads. Alternatively, no empty space is provided there being additional, grounded, detectors provided between the data and reference detectors. (author)

Pulse height model for deuterated scintillation detectors

International Nuclear Information System (INIS)

Wang, Haitang; Enqvist, Andreas

2015-01-01

An analytical model of light pulse height distribution for finite deuterated scintillation detectors is created using the impulse approximation. Particularly, the energy distribution of a scattered neutron is calculated based on an existing collision probability scheme for general cylindrical shaped detectors considering double differential cross-sections. The light pulse height distribution is analytically and numerically calculated by convoluting collision sequences with the light output function for an EJ-315 detector from our measurements completed at Ohio University. The model provides a good description of collision histories capturing transferred neutron energy in deuterium-based scintillation materials. The resulting light pulse height distribution details pulse compositions and their corresponding contributions. It shows that probabilities of neutron collision with carbon and deuterium nuclei are comparable, however the light pulse amplitude due to collisions with carbon nuclei is small and mainly located at the lower region of the light pulse distribution axis. The model can explore those neutron interaction events that generate pulses near or below a threshold that would be imposed in measurements. A comparison is made between the light pulse height distributions given by the analytical model and measurements. It reveals a significant probability of a neutron generating a small light pulse due to collisions with carbon nuclei when compared to larger light pulse generated by collisions involving deuterium nuclei. This model is beneficial to understand responses of scintillation materials and pulse compositions, as well as nuclei information extraction from recorded pulses.

Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors

Energy Technology Data Exchange (ETDEWEB)

Beck, Patrick R. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

2010-01-07

Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.

Superlattice electroabsorption radiation detector

International Nuclear Information System (INIS)

Cooke, B.J.

1993-06-01

This paper provides a preliminary investigation of a new class of superlattice electroabsorption radiation detectors that employ direct optical modulation for high-speed, two-dimensional (2-D), high-resolution imaging. Applications for the detector include nuclear radiation measurements, tactical guidance and detection (laser radar), inertial fusion plasma studies, and satellite-based sensors. Initial calculations discussed in this paper indicate that a 1.5-μm (GaAlAs) multi-quantum-well (MQW) Fabry-Perot detector can respond directly to radiation of energies 1 eV to 10 KeV, and indirectly (with scattering targets) up through gamma, with 2-D sample rates on the order of 20 ps

A new self-powered flux detector

International Nuclear Information System (INIS)

Allan, C.J.

1979-11-01

It has been found that an Inconel-Inconel coaxial cable can be used as a fast-responding, neutron, self-powered flux detector if the core wire is sufficiently large. Test results obtained with such a detector, having a core wire approximately 1.5 mm in diameter, are presented. Other materials suitable for use as an emitter material, in such a relatively large diameter detector, also are included. (auth)

Sandwich veto detector at COMPASS experiment

International Nuclear Information System (INIS)

Sarkar, S.; Dasgupta, S.S.; Calcutta-COMPASS group

2010-01-01

This paper presents the newly build Sandwich Detector for 190 GeV hadron run of COMPASS Experiment at CERN. The technical details and the testing procedures are included to highlight the physics objective of the installation. Single electron detection techniques has been developed and used to scale the performance of the detector. This analysis can predict the number of single electrons per MIP at the scintillation detector. (author)

Finite element and finite difference methods in electromagnetic scattering

CERN Document Server

Morgan, MA

2013-01-01

This second volume in the Progress in Electromagnetic Research series examines recent advances in computational electromagnetics, with emphasis on scattering, as brought about by new formulations and algorithms which use finite element or finite difference techniques. Containing contributions by some of the world's leading experts, the papers thoroughly review and analyze this rapidly evolving area of computational electromagnetics. Covering topics ranging from the new finite-element based formulation for representing time-harmonic vector fields in 3-D inhomogeneous media using two coupled sca

Study guide for applied finite mathematics

CERN Document Server

Macri, Nicholas A

1982-01-01

Study Guide for Applied Finite Mathematics, Third Edition is a study guide that introduces beginners to the fundamentals of finite mathematics and its various realistic and relevant applications. Some applications of probability, game theory, and Markov chains are given. Each chapter includes exercises, and each set begins with basic computational ""drill"" problems and then progresses to problems with more substance.Comprised of 10 chapters, this book begins with exercises related to set theory and concepts such as the union and intersection of sets. Exercises on Cartesian coordinate

Finite and profinite quantum systems

CERN Document Server

Vourdas, Apostolos

2017-01-01

This monograph provides an introduction to finite quantum systems, a field at the interface between quantum information and number theory, with applications in quantum computation and condensed matter physics. The first major part of this monograph studies the so-called `qubits' and `qudits', systems with periodic finite lattice as position space. It also discusses the so-called mutually unbiased bases, which have applications in quantum information and quantum cryptography. Quantum logic and its applications to quantum gates is also studied. The second part studies finite quantum systems, where the position takes values in a Galois field. This combines quantum mechanics with Galois theory. The third part extends the discussion to quantum systems with variables in profinite groups, considering the limit where the dimension of the system becomes very large. It uses the concepts of inverse and direct limit and studies quantum mechanics on p-adic numbers. Applications of the formalism include quantum optics and ...

DETECTORS USED IN PARTICLE PHYSICS RESEARCH

Energy Technology Data Exchange (ETDEWEB)

Melissines, A. C.

1963-10-15

Detectors used in particle physics are discussed, and their specific properties are compared. With the pictorial'' devices are included nuclear emulsions, cloud and bubble chambers, and spark chambers. Included in the digital'' devices are counters, e.g., the Geiger counter, scintillation counters, solid-state detectors, Cherenkov counters, and spark counters. Sensitivity, resolving power, time resolutions, saturation level, and energy detection are discussed. (R.E.U.)

ANSYS mechanical APDL for finite element analysis

CERN Document Server

Thompson, Mary Kathryn

2017-01-01

ANSYS Mechanical APDL for Finite Element Analysis provides a hands-on introduction to engineering analysis using one of the most powerful commercial general purposes finite element programs on the market. Students will find a practical and integrated approach that combines finite element theory with best practices for developing, verifying, validating and interpreting the results of finite element models, while engineering professionals will appreciate the deep insight presented on the program's structure and behavior. Additional topics covered include an introduction to commands, input files, batch processing, and other advanced features in ANSYS. The book is written in a lecture/lab style, and each topic is supported by examples, exercises and suggestions for additional readings in the program documentation. Exercises gradually increase in difficulty and complexity, helping readers quickly gain confidence to independently use the program. This provides a solid foundation on which to build, preparing readers...

The ALICE-HMPID Detector Control System: Its evolution towards an expert and adaptive system

Science.gov (United States)

De Cataldo, G.; Franco, A.; Pastore, C.; Sgura, I.; Volpe, G.

2011-05-01

The High Momentum Particle IDentification (HMPID) detector is a proximity focusing Ring Imaging Cherenkov (RICH) for charged hadron identification. The HMPID is based on liquid C 6F 14 as the radiator medium and on a 10 m 2 CsI coated, pad segmented photocathode of MWPCs for UV Cherenkov photon detection. To ensure full remote control, the HMPID is equipped with a detector control system (DCS) responding to industrial standards for robustness and reliability. It has been implemented using PVSS as Slow Control And Data Acquisition (SCADA) environment, Programmable Logic Controller as control devices and Finite State Machines for modular and automatic command execution. In the perspective of reducing human presence at the experiment site, this paper focuses on DCS evolution towards an expert and adaptive control system, providing, respectively, automatic error recovery and stable detector performance. HAL9000, the first prototype of the HMPID expert system, is then presented. Finally an analysis of the possible application of the adaptive features is provided.

The ALICE-HMPID Detector Control System: Its evolution towards an expert and adaptive system

International Nuclear Information System (INIS)

De Cataldo, G.; Franco, A.; Pastore, C.; Sgura, I.; Volpe, G.

2011-01-01

The High Momentum Particle IDentification (HMPID) detector is a proximity focusing Ring Imaging Cherenkov (RICH) for charged hadron identification. The HMPID is based on liquid C 6 F 14 as the radiator medium and on a 10 m 2 CsI coated, pad segmented photocathode of MWPCs for UV Cherenkov photon detection. To ensure full remote control, the HMPID is equipped with a detector control system (DCS) responding to industrial standards for robustness and reliability. It has been implemented using PVSS as Slow Control And Data Acquisition (SCADA) environment, Programmable Logic Controller as control devices and Finite State Machines for modular and automatic command execution. In the perspective of reducing human presence at the experiment site, this paper focuses on DCS evolution towards an expert and adaptive control system, providing, respectively, automatic error recovery and stable detector performance. HAL9000, the first prototype of the HMPID expert system, is then presented. Finally an analysis of the possible application of the adaptive features is provided.

The silicon strip detector at the Mark 2

International Nuclear Information System (INIS)

Jacobsen, R.; Golubev, V.; Lueth, V.; Barnett, B.; Dauncey, P.; Matthews, J.; Adolphsen, C.; Burchat, P.; Gratta, G.; King, M.; Labarga, L.; Litke, A.; Turala, M.; Zaccardelli, C.

1990-04-01

We have installed a Silicon Strip Vertex Detector in the Mark II detector at the Stanford Linear Collider. We report on the performance of the detector during a recent test run, including backgrounds, stability and charged particle tracking. 10 refs., 9 figs

Theoretical response of a ZnS(Ag) scintillation detector to alpha-emitting sources and suggested applications

International Nuclear Information System (INIS)

Skrable, K.W.; Phoenix, K.A.; Chabot, G.E.; French, C.S.; Jo, M.; Falo, G.A.

1991-01-01

The classic problem of alpha absorption is discussed in terms of the quantitative determination of the activity of weightless alpha sources and the specific alpha activity of extended sources accounting for absorption in the source medium and the window of a large area ZnS(Ag) scintillation detector. The relationship for the expected counting rate gamma of a monoenergetic source of active area A, specific alpha activity C, and thickness H that exceeds the effective mass density range Rs of the alpha particle in the source medium can be expressed by a quadratic equation in the window thickness x when this source is placed in direct contact with the window of the ZnS(Ag) detector. This expression also gives the expected counting rate of a finite detector of sensitive area A exposed to an infinite homogeneous source medium. Counting rates y obtained for a source separated from a ZnS(Ag) detector by different thicknesses x of window material can be used to estimate parameter values in the quadratic equation, y = a + bx + cx2. The experimental value determined for the coefficient b provides a direct estimation of the specific activity C. This coefficient, which depends on the ratio of the ranges in the source medium and detector window and not the ranges themselves, is essentially independent of the energy of the alpha particle. Although certain experimental precautions must be taken, this method for estimating the specific activity C is essentially an absolute method that does not require the use of standards, special calibrations, or complicated radiochemical procedures. Applications include the quantitative determination of Rn and progeny in air, water, and charcoal, and the measurement of the alpha activity in soil and on air filter samples

SU-F-T-490: Separating Effects Influencing Detector Response in Small MV Photon Fields

Energy Technology Data Exchange (ETDEWEB)

Wegener, S; Sauer, O [University of Wuerzburg, Wuerzburg (Germany)

2016-06-15

Purpose: Different detector properties influence their responses especially in field sizes below the lateral electron range. Due to the finite active volume, the detector density and electron perturbation at other structural parts, the response factor is in general field size dependent. We aimed to visualize and separate the main effects contributing to detector behavior for a variety of detector types. This was achieved in an experimental setup, shielding the field center. Thus, effects caused by scattered radiation could be examined separately. Methods: Signal ratios for field sizes down to 8 mm (SSD 90 cm, water depth 10 cm) of a 6MV beam from a Siemens Primus LINAC were recorded with several detectors: PTW microDiamond and PinPoint ionization chamber, shielded diodes (PTW P-60008, IBA PFD and SNC Edge) and unshielded diodes (PTW E-60012 and IBA SFD). Measurements were carried out in open fields and with an aluminum pole of 4 mm diameter as a central block. The geometric volume effect was calculated from profiles obtained with Gafchromic EBT3 film, evaluated using FilmQA Pro software (Ashland, USA). Results: Volume corrections were 1.7% at maximum. After correction, in small open fields, unshielded diodes showed a lower response than the diamond, i.e. diamond detector over-response seems to be higher than that for unshielded diodes. Beneath the block, this behavior was amplified by a factor of 2. For the shielded diodes, the overresponse for small open fields could be confirmed. However their lateral response behavior was strongly type dependent, e.g. the signal ratio dropped from 1.02 to 0.98 for the P-60008 diode. Conclusion: The lateral detector response was experimentally examined. Detector volume and density alone do not fully account for the field size dependence of detector response. Detector construction details play a major role, especially for shielded diodes.

Generalized two-dimensional (2D) linear system analysis metrics (GMTF, GDQE) for digital radiography systems including the effect of focal spot, magnification, scatter, and detector characteristics.

Science.gov (United States)

Jain, Amit; Kuhls-Gilcrist, Andrew T; Gupta, Sandesh K; Bednarek, Daniel R; Rudin, Stephen

2010-03-01

The MTF, NNPS, and DQE are standard linear system metrics used to characterize intrinsic detector performance. To evaluate total system performance for actual clinical conditions, generalized linear system metrics (GMTF, GNNPS and GDQE) that include the effect of the focal spot distribution, scattered radiation, and geometric unsharpness are more meaningful and appropriate. In this study, a two-dimensional (2D) generalized linear system analysis was carried out for a standard flat panel detector (FPD) (194-micron pixel pitch and 600-micron thick CsI) and a newly-developed, high-resolution, micro-angiographic fluoroscope (MAF) (35-micron pixel pitch and 300-micron thick CsI). Realistic clinical parameters and x-ray spectra were used. The 2D detector MTFs were calculated using the new Noise Response method and slanted edge method and 2D focal spot distribution measurements were done using a pin-hole assembly. The scatter fraction, generated for a uniform head equivalent phantom, was measured and the scatter MTF was simulated with a theoretical model. Different magnifications and scatter fractions were used to estimate the 2D GMTF, GNNPS and GDQE for both detectors. Results show spatial non-isotropy for the 2D generalized metrics which provide a quantitative description of the performance of the complete imaging system for both detectors. This generalized analysis demonstrated that the MAF and FPD have similar capabilities at lower spatial frequencies, but that the MAF has superior performance over the FPD at higher frequencies even when considering focal spot blurring and scatter. This 2D generalized performance analysis is a valuable tool to evaluate total system capabilities and to enable optimized design for specific imaging tasks.

Composite Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-03-07

In this chapter, we extend the previous results of Chap. 2 to the more general case of composite finite sums. We describe what composite finite sums are and how their analysis can be reduced to the analysis of simple finite sums using the chain rule. We apply these techniques, next, on numerical integration and on some identities of Ramanujan.

Composite Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-01-01

In this chapter, we extend the previous results of Chap. 2 to the more general case of composite finite sums. We describe what composite finite sums are and how their analysis can be reduced to the analysis of simple finite sums using the chain rule. We apply these techniques, next, on numerical integration and on some identities of Ramanujan.

Recent Developments in GEM-Based Neutron Detectors

International Nuclear Information System (INIS)

Saenboonruang, K.

2014-01-01

The gas electron multiplier (GEM) detector is a relatively new gaseous detector that has been used for less than 20 years. Since the discovery in 1997 by F. Sauli, the GEM detector has shown excellent properties including high rate capability, excellent resolutions, low discharge probability, and excellent radiation hardness. These promising properties have led the GEM detector to gain popularity and attention amongst physicists and researchers. In particular, the GEM detector can also be modified to be used as a neutron detector by adding appropriate neutron converters. With properties stated above and the need to replace the expensive 3 He-based neutron detectors, the GEM-based neutron detector will be one of the most powerful and affordable neutron detectors. Applications of the GEM-based neutron detectors vary from researches in nuclear and particle physics, neutron imaging, and national security. Although several promising progresses and results have been shown and published in the past few years, further improvement is still needed in order to improve the low neutron detection efficiency (only a few percent) and to widen the possibilities for other uses.

Exact analytical solution of the convolution integral equation for a general profile fitting function and Gaussian detector kernel

International Nuclear Information System (INIS)

Garcia-Vicente, F.; Rodriguez, C.

2000-01-01

One of the most important aspects in the metrology of radiation fields is the problem of the measurement of dose profiles in regions where the dose gradient is large. In such zones, the 'detector size effect' may produce experimental measurements that do not correspond to reality. Mathematically it can be proved, under some general assumptions of spatial linearity, that the disturbance induced in the measurement by the effect of the finite size of the detector is equal to the convolution of the real profile with a representative kernel of the detector. In this work the exact relation between the measured profile and the real profile is shown, through the analytical resolution of the integral equation for a general type of profile fitting function using Gaussian convolution kernels. (author)

Axial anomaly at finite temperature and finite density

International Nuclear Information System (INIS)

Qian Zhixin; Su Rukeng; Yu, P.K.N.

1994-01-01

The U(1) axial anomaly in a hot fermion medium is investigated by using the real time Green's function method. After calculating the lowest order triangle diagrams, we find that finite temperature as well as finite fermion density does not affect the axial anomaly. The higher order corrections for the axial anomaly are discussed. (orig.)

Detectors for proton counting. Si-APD and scintillation detectors

International Nuclear Information System (INIS)

Kishimoto, Shunji

2008-01-01

Increased intensity of synchrotron radiation requests users to prepare photon pulse detectors having higher counting rates. As detectors for photon counting, silicon-avalanche photodiode (Si-APD) and scintillation detectors were chosen for the fifth series of detectors. Principle of photon detection by pulse and need of amplification function of the detector were described. Structure and working principle, high counting rate measurement system, bunch of electrons vs. counting rate, application example of NMR time spectroscopy measurement and comments for users were described for the Si-APD detector. Structure of scintillator and photomultiplier tube, characteristics of scintillator and performance of detector were shown for the NaI detector. Future development of photon pulse detectors was discussed. (T. Tanaka)

Finite entanglement entropy and spectral dimension in quantum gravity

Energy Technology Data Exchange (ETDEWEB)

Arzano, Michele [Rome Univ. (Italy). Dipt. di Fisica; INFN, Rome (Italy); Calcagni, Gianluca [CSIC, Madrid (Spain). Inst. de Estructura de la Materia

2017-12-15

What are the conditions on a field theoretic model leading to a finite entanglement entropy density? We prove two very general results: (1) Ultraviolet finiteness of a theory does not guarantee finiteness of the entropy density; (2) If the spectral dimension of the spatial boundary across which the entropy is calculated is non-negative at all scales, then the entanglement entropy cannot be finite. These conclusions, which we verify in several examples, negatively affect all quantum-gravity models, since their spectral dimension is always positive. Possible ways out are considered, including abandoning the definition of the entanglement entropy in terms of the boundary return probability or admitting an analytic continuation (not a regularization) of the usual definition. In the second case, one can get a finite entanglement entropy density in multi-fractional theories and causal dynamical triangulations. (orig.)

Finite entanglement entropy and spectral dimension in quantum gravity

Science.gov (United States)

Arzano, Michele; Calcagni, Gianluca

2017-12-01

What are the conditions on a field theoretic model leading to a finite entanglement entropy density? We prove two very general results: (1) Ultraviolet finiteness of a theory does not guarantee finiteness of the entropy density; (2) If the spectral dimension of the spatial boundary across which the entropy is calculated is non-negative at all scales, then the entanglement entropy cannot be finite. These conclusions, which we verify in several examples, negatively affect all quantum-gravity models, since their spectral dimension is always positive. Possible ways out are considered, including abandoning the definition of the entanglement entropy in terms of the boundary return probability or admitting an analytic continuation (not a regularization) of the usual definition. In the second case, one can get a finite entanglement entropy density in multi-fractional theories and causal dynamical triangulations.

Finite entanglement entropy and spectral dimension in quantum gravity

International Nuclear Information System (INIS)

Arzano, Michele; Calcagni, Gianluca

2017-01-01

What are the conditions on a field theoretic model leading to a finite entanglement entropy density? We prove two very general results: (1) Ultraviolet finiteness of a theory does not guarantee finiteness of the entropy density; (2) If the spectral dimension of the spatial boundary across which the entropy is calculated is non-negative at all scales, then the entanglement entropy cannot be finite. These conclusions, which we verify in several examples, negatively affect all quantum-gravity models, since their spectral dimension is always positive. Possible ways out are considered, including abandoning the definition of the entanglement entropy in terms of the boundary return probability or admitting an analytic continuation (not a regularization) of the usual definition. In the second case, one can get a finite entanglement entropy density in multi-fractional theories and causal dynamical triangulations. (orig.)

Detector for flow abnormalities in gaseous diffusion plant compressors

Science.gov (United States)

Smith, S.F.; Castleberry, K.N.

1998-06-16

A detector detects a flow abnormality in a plant compressor which outputs a motor current signal. The detector includes a demodulator/lowpass filter demodulating and filtering the motor current signal producing a demodulated signal, and first, second, third and fourth bandpass filters connected to the demodulator/lowpass filter, and filtering the demodulated signal in accordance with first, second, third and fourth bandpass frequencies generating first, second, third and fourth filtered signals having first, second, third and fourth amplitudes. The detector also includes first, second, third and fourth amplitude detectors connected to the first, second, third and fourth bandpass filters respectively, and detecting the first, second, third and fourth amplitudes, and first and second adders connected to the first and fourth amplitude detectors and the second and third amplitude detectors respectively, and adding the first and fourth amplitudes and the second and third amplitudes respectively generating first and second added signals. Finally, the detector includes a comparator, connected to the first and second adders, and comparing the first and second added signals and detecting the abnormal condition in the plant compressor when the second added signal exceeds the first added signal by a predetermined value. 6 figs.

Modeling and design of X-rays bidimensional detectors; Modelagem e projeto de detectores bidimensionais para radiacao-X

Energy Technology Data Exchange (ETDEWEB)

Quisbert, Elmer Paz Alcon

2000-03-01

In this work has been developed the scintillating fiber optic and semiconductor devices based 2-D detector design, modeling and performance evaluation using Monte Carlo methods, for high X-ray energy range (10-140 kV) radiography and tomography applications. These processes allowed us, also, the imaging system parameters and components optimization and appropriate detector design. The model estimated the detectors performance parameters (DQE, MTF and SNR), and radiation risk (in terms of mean absorbed dose in the patient) and to show up how the sequence of physical processes in X-ray detection influence the performance of this imaging PFOC detectors. In this way, the modeling of the detector includes the statistics of the spatial distribution of absorbed X-rays and of X-ray to light conversion, its transmission, and the light quanta conversion into electrons. Also contributions to noise from the detection system chain is included, mainly the CCD detector ambient noise. Performance prediction, based on calculation taken from simulations, illustrates how such detectors meet the exacting requirements of some medical and industrial applications. Also, it is envisaged that our modeling procedure of the imaging system will be suitable not only for investigating how the system components should be best designed but for CT and RD system performance prediction. The powerful techniques would enable us to give advice for future development, in this field, in search of more dose-efficient imaging systems. (author)

Locally Finite Root Supersystems

OpenAIRE

Yousofzadeh, Malihe

2013-01-01

We introduce the notion of locally finite root supersystems as a generalization of both locally finite root systems and generalized root systems. We classify irreducible locally finite root supersystems.

Ionization detector

Energy Technology Data Exchange (ETDEWEB)

Solomon, E E

1976-02-27

This invention concerns a fire detection system making use of a beta source. The ionisation detector includes a first and second chamber respectively comprising a first and second electrode, preferably a plate, with a common electrode separating the first and second chamber. Communication is provided between these chambers through a set of orifices and each chamber also has a set of orifices for communication with the ambient atmosphere. One or both chambers can comprise a particle source, preferably beta. The detector also has an adjustable electrode housed in one of the chambers to regulate the voltage between the fixed electrode of this chamber and the common electrode located between the chambers. The electrodes of the structure are connected to a detection circuit that spots a change in the ionisation current when a fire alarm condition arises. The detection circuit of a new type includes a relaxation oscillator with a programmable unijunction transistor and a light emitting diode.

Electronically shielded solid state charged particle detector

International Nuclear Information System (INIS)

Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

1996-01-01

An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig

Vertex detectors

International Nuclear Information System (INIS)

Lueth, V.

1992-07-01

The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10 -13 s, among them the τ lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation

Hybrid finite difference/finite element immersed boundary method.

Science.gov (United States)

E Griffith, Boyce; Luo, Xiaoyu

2017-12-01

The immersed boundary method is an approach to fluid-structure interaction that uses a Lagrangian description of the structural deformations, stresses, and forces along with an Eulerian description of the momentum, viscosity, and incompressibility of the fluid-structure system. The original immersed boundary methods described immersed elastic structures using systems of flexible fibers, and even now, most immersed boundary methods still require Lagrangian meshes that are finer than the Eulerian grid. This work introduces a coupling scheme for the immersed boundary method to link the Lagrangian and Eulerian variables that facilitates independent spatial discretizations for the structure and background grid. This approach uses a finite element discretization of the structure while retaining a finite difference scheme for the Eulerian variables. We apply this method to benchmark problems involving elastic, rigid, and actively contracting structures, including an idealized model of the left ventricle of the heart. Our tests include cases in which, for a fixed Eulerian grid spacing, coarser Lagrangian structural meshes yield discretization errors that are as much as several orders of magnitude smaller than errors obtained using finer structural meshes. The Lagrangian-Eulerian coupling approach developed in this work enables the effective use of these coarse structural meshes with the immersed boundary method. This work also contrasts two different weak forms of the equations, one of which is demonstrated to be more effective for the coarse structural discretizations facilitated by our coupling approach. © 2017 The Authors International  Journal  for  Numerical  Methods  in  Biomedical  Engineering Published by John Wiley & Sons Ltd.

A New Virtual Point Detector Concept for a HPGe detector

International Nuclear Information System (INIS)

Byun, Jong In; Yun, Ju Yong

2009-01-01

For last several decades, the radiation measurement and radioactivity analysis techniques using gamma detectors have been well established. Especially , the study about the detection efficiency has been done as an important part of gamma spectrometry. The detection efficiency depends strongly on source-to-detector distance. The detection efficiency with source-to-detector distance can be expressed by a complex function of geometry and physical characteristics of gamma detectors. In order to simplify the relation, a virtual point detector concept was introduced by Notea. Recently, further studies concerning the virtual point detector have been performed. In previous other works the virtual point detector has been considered as a fictitious point existing behind the detector end cap. However the virtual point detector position for the front and side of voluminous detectors might be different due to different effective central axis of them. In order to more accurately define the relation, therefore, we should consider the virtual point detector for the front as well as side and off-center of the detector. The aim of this study is to accurately define the relation between the detection efficiency and source-to-detector distance with the virtual point detector. This paper demonstrates the method to situate the virtual point detectors for a HPGe detector. The new virtual point detector concept was introduced for three area of the detector and its characteristics also were demonstrated by using Monte Carlo Simulation method. We found that the detector has three virtual point detectors except for its rear area. This shows that we should consider the virtual point detectors for each area when applying the concept to radiation measurement. This concept can be applied to the accurate geometric simplification for the detector and radioactive sources.

Status of diamond particle detectors

Science.gov (United States)

Krammer, M.; Adam, W.; Bauer, C.; Berdermann, E.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fish, D.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knöpfle, K. T.; Manfredi, P. F.; Meier, D.; Mishina, M.; LeNormand, F.; Pan, L. S.; Pernegger, H.; Pernicka, M.; Re, V.; Riester, G. L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.

1998-11-01

To continue the exciting research in the field of particle physics new accelerators and experiments are under construction. In some of these experiments, e.g. ATLAS and CMS at the Large Hadron Collider at CERN or HERA-B at DESY, the detectors have to withstand an extreme environment. The detectors must be radiation hard, provide a very fast signal, and be as thin as possible. The properties of CVD diamond allow to fulfill these requirements and make it an ideal material for the detectors close to the interaction region of these experiments, i.e. the vertex detectors or the inner trackers. The RD42 collaboration is developing diamond detectors for these applications. The program of RD42 includes the improvement of the charge collection properties of CVD diamond, the study of the radiation hardness and the development of low-noise radiation hard readout electronics. An overview of the progress achieved during the last years will be given.

Simple Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-01-01

We will begin our treatment of summability calculus by analyzing what will be referred to, throughout this book, as simple finite sums. Even though the results of this chapter are particular cases of the more general results presented in later chapters, they are important to start with for a few reasons. First, this chapter serves as an excellent introduction to what summability calculus can markedly accomplish. Second, simple finite sums are encountered more often and, hence, they deserve special treatment. Third, the results presented in this chapter for simple finite sums will, themselves, be used as building blocks for deriving the most general results in subsequent chapters. Among others, we establish that fractional finite sums are well-defined mathematical objects and show how various identities related to the Euler constant as well as the Riemann zeta function can actually be derived in an elementary manner using fractional finite sums.

Simple Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-03-07

We will begin our treatment of summability calculus by analyzing what will be referred to, throughout this book, as simple finite sums. Even though the results of this chapter are particular cases of the more general results presented in later chapters, they are important to start with for a few reasons. First, this chapter serves as an excellent introduction to what summability calculus can markedly accomplish. Second, simple finite sums are encountered more often and, hence, they deserve special treatment. Third, the results presented in this chapter for simple finite sums will, themselves, be used as building blocks for deriving the most general results in subsequent chapters. Among others, we establish that fractional finite sums are well-defined mathematical objects and show how various identities related to the Euler constant as well as the Riemann zeta function can actually be derived in an elementary manner using fractional finite sums.

An Analysis of the Control Hierarchy Modeling of the CMS Detector Control System

CERN Document Server

Ling Hwong, Yi

2010-01-01

The supervisory level of the Detector Control System (DCS) of the CMS experiment is implemented using Finite State Machines (FSM), which model the behaviors and control the operations of all the sub-detectors and support services. The FSM tree of the whole CMS experiment consists of more than 30.000 nodes. An analysis of a system of such size is a complex task but is a crucial step towards the improvement of the overall performance of the FSM system. This paper presents the analysis of the CMS FSM system using the micro Common Representation Language 2 (mcrl2) methodology. Individual mCRL2 models are obtained for the FSM systems of the CMS sub-detectors using the ASF+SDF automated translation tool. Different mCRL2 operations are applied to the mCRL2 models. A mCRL2 simulation tool is used to closer examine the system. Visualization of a system based on the exploration of its state space is enabled with a mCRL2 tool. Requirements such as command and state propagation are expressed using modal mu-calculus and c...

Transmutation detectors

Energy Technology Data Exchange (ETDEWEB)

Viererbl, L., E-mail: vie@ujv.c [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Lahodova, Z. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Klupak, V. [Nuclear Research Institute Rez plc (Czech Republic); Sus, F. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Kucera, J. [Research Centre Rez Ltd. (Czech Republic); Nuclear Physics Institute, Academy of Sciences of the Czech Republic (Czech Republic); Kus, P.; Marek, M. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic)

2011-03-11

We have designed a new type of detectors, called transmutation detectors, which can be used primarily for neutron fluence measurement. The transmutation detector method differs from the commonly used activation detector method in evaluation of detector response after irradiation. Instead of radionuclide activity measurement using radiometric methods, the concentration of stable non-gaseous nuclides generated by transmutation in the detector is measured using analytical methods like mass spectrometry. Prospective elements and nuclear reactions for transmutation detectors are listed and initial experimental results are given. The transmutation detector method could be used primarily for long-term measurement of neutron fluence in fission nuclear reactors, but in principle it could be used for any type of radiation that can cause transmutation of nuclides in detectors. This method could also be used for measurement in accelerators or fusion reactors.

Transmutation detectors

International Nuclear Information System (INIS)

Viererbl, L.; Lahodova, Z.; Klupak, V.; Sus, F.; Kucera, J.; Kus, P.; Marek, M.

2011-01-01

We have designed a new type of detectors, called transmutation detectors, which can be used primarily for neutron fluence measurement. The transmutation detector method differs from the commonly used activation detector method in evaluation of detector response after irradiation. Instead of radionuclide activity measurement using radiometric methods, the concentration of stable non-gaseous nuclides generated by transmutation in the detector is measured using analytical methods like mass spectrometry. Prospective elements and nuclear reactions for transmutation detectors are listed and initial experimental results are given. The transmutation detector method could be used primarily for long-term measurement of neutron fluence in fission nuclear reactors, but in principle it could be used for any type of radiation that can cause transmutation of nuclides in detectors. This method could also be used for measurement in accelerators or fusion reactors.

Thermal simulations of the new design for the BELLE silicon vertex detector

International Nuclear Information System (INIS)

Dragic, J.

2000-01-01

Full text: The experienced imperfections of the BELLE silicon vertex detector, SVD1 motioned the design of a new detector, SVD2, which targets on improving the main weaknesses encountered in the old design. In this report we focus on tile thermal aspects of the SVD2 ladder, whereby sufficient cooling of the detector is necessary in order to minimise the detector leakage currents. It is estimated that reducing the temperature of the silicon detector from 25 deg C to 15 deg C would result in a 50% reduction in leak current. Further, cooling the detector would help minimize mechanical stresses from the thermal cycling. Our task is to ensure that the heat generated by the readout chips is conducted down the SVD hybrid unit effectively, such that the chip and the hybrid temperature does not overbear the SVD silicon sensor temperature. We considered the performance of two materials to act as a heat spreading plate which is glued between the two hybrids in order to improve the heat conductivity of the hybrid unit, namely Copper and Thermal Pyrolytic Graphite (TPG). The effects of other ladder components were also considered in order to enhance the cooling of the silicon detectors. Finite element analysis with ANSYS software was used to simulate the thermal conditions of the SVD2 hybrid unit, in accordance with the baseline design for the mechanical structure of the ladder. It was found that Cu was a preferred material as it achieved equivalent silicon sensor cooling (3.6 deg C above cooling point), while its mechanical properties rendered it a lot more practical. Suppressing, the thermal path via a rib support block, by increasing its thermal resistivity, as well as increasing thermal conductivity of the ribs in the hybrid region, were deemed essential in the effective cooling of the silicon sensors

Detector simulations with DD4hep

CERN Document Server

AUTHOR|(SzGeCERN)668365; Frank, Markus; Gaede, Frank-Dieter; Lu, Shaojun; Nikiforou, Nikiforos; Sailer, Andre

2017-01-01

Detector description is a key component of detector design studies, test beam analyses, and most of particle physics experiments that require the simulation of more and more different detector geometries and event types. This paper describes DD4hep, which is an easy-to-use yet flexible and powerful detector description framework that can be used for detector simulation and also extended to specific needs for a particular working environment. Linear collider detector concepts ILD, SiD and CLICdp as well as detector development collaborations CALICE and FCal have chosen to adopt the DD4hep geometry framework and its DDG4 pathway to Geant4 as its core simulation and reconstruction tools. The DDG4 plugins suite includes a wide variety of input formats, provides access to the Geant4 particle gun or general particles source and allows for handling of Monte Carlo truth information, e.g. by linking hits and the primary particle that caused them, which is indispensable for performance and efficiency studies. An extend...

Thermal Module Tests with Irradiated 070 Detectors.

CERN Document Server

HOWCROFT, C L F

1998-01-01

Four n-in-n detectors were irradiated at KEK to a fluence of 3*1014 protons cm-2. These were used to construct a thermal barrel module to 070 drawings with an A3-90 baseboard at the Rutherford Appleton Laboratory. Thermal testes were conducted on the module, examining the runaway point and the temperatures across the silicon. The results obtained were used to calculate the runaway point under ATLAS conditions. It was concluded that this module meets the specifications in the Technical Design Report, of 160 mW mm-2@ 0°C for runaway and less than 5°C across the silicon. The module was also compared to a Finite Element Analysis, and showed a good agreement.

Radiation detectors for reactors

International Nuclear Information System (INIS)

Balagi, V.

2005-01-01

Detection and measurement of radiation plays a vital role in nuclear reactors from the point of view of control and safety, personnel protection and process control applications. Various types of radiation are measured over a wide range of intensity. Consequently a variety of detectors find use in nuclear reactors. Some of these devices have been developed in Electronics Division. They include gas-filled detectors such as 10 B-lined proportional counters and chambers, fission detectors and BF 3 counters are used for the measurement of neutron flux both for reactor control and safety, process control as well as health physics instrumentation. In-core neutron flux instrumentation employs the use detectors such as miniature fission detectors and self-powered detectors. In this development effort, several indigenous materials, technologies and innovations have been employed to suit the specific requirement of nuclear reactor applications. This has particular significance in view of the fact that several new types of reactors such as P-4, PWR and AHWR critical facilities, FBTR, PFBR as well as the refurbishment of old units like CIRUS are being developed. The development work has sought to overcome some difficulties associated with the non-availability of isotopically enriched neutron-sensing materials, achieving all-welded construction etc. The present paper describes some of these innovations and performance results. (author)

Microprocessor-based accelerating power level detector

Energy Technology Data Exchange (ETDEWEB)

Nagpal, M.; Zarecki, W.; Albrecht, J.C.

1994-01-01

An accelerating power level detector was built using state-of-the-art microprocessor technology at Powertech Labs Inc. The detector will monitor the real power flowing in two 300 kV transmission lines out of Kemano Hydroelectric Generating Station and will detect any sudden loss of load due to a fault on either line under certain pre-selected power flow conditions. This paper discusses the criteria of operation for the detector and its implementation details, including digital processing, hardware, and software.

The principle of finiteness – a guideline for physical laws

International Nuclear Information System (INIS)

Sternlieb, Abraham

2013-01-01

I propose a new principle in physics-the principle of finiteness (FP). It stems from the definition of physics as a science that deals with measurable dimensional physical quantities. Since measurement results including their errors, are always finite, FP postulates that the mathematical formulation of legitimate laws in physics should prevent exactly zero or infinite solutions. I propose finiteness as a postulate, as opposed to a statement whose validity has to be corroborated by, or derived theoretically or experimentally from other facts, theories or principles. Some consequences of FP are discussed, first in general, and then more specifically in the fields of special relativity, quantum mechanics, and quantum gravity. The corrected Lorentz transformations include an additional translation term depending on the minimum length epsilon. The relativistic gamma is replaced by a corrected gamma, that is finite for v=c. To comply with FP, physical laws should include the relevant extremum finite values in their mathematical formulation. An important prediction of FP is that there is a maximum attainable relativistic mass/energy which is the same for all subatomic particles, meaning that there is a maximum theoretical value for cosmic rays energy. The Generalized Uncertainty Principle required by Quantum Gravity is actually a necessary consequence of FP at Planck's scale. Therefore, FP may possibly contribute to the axiomatic foundation of Quantum Gravity.

Aging: Learning to Live a Finite Life.

Science.gov (United States)

Baars, Jan

2017-10-01

Although biodemographic research informs us that life expectancies have risen impressively during the last century, this has not led to much interest in these new horizons of aging. The instrumentalist culture of late modern societies, including its health cure system, has clearly difficulties to relate to the elusive but inevitable limitations of finite life. Moreover, as most people can be expected to survive into old age, thinking about finitude is easily postponed and reserved for those who are "really old." Indeed, a meaningful and realistic understanding of aging needs to include a confrontation with the finitude of life. Instead of reducing aging to the opposite or continuation of vital adulthood, it should be seen as something with a potentially broad and deep significance: a process of learning to live a finite life. As a contribution to this cultural repositioning of aging, the article presents a philosophical exploration of finitude and finite life. Among the discussed topics are the Stoic and Epicurean ways of living with death but also the necessity to expand the meaning of "finitude" beyond mortality. Aging is foremost a process of living through changes that are largely beyond our control although they require active responding. Next, individualistic or existentialist interpretations are criticized because finite lives presuppose a social world in which they emerge and on which they depend. Unfortunately, aging, the most important experiential source of knowledge about what it is to live a finite life, is neglected by the same culture that needs its wisdom. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Self-Powered Neutron and Gamma Detectors for In-Core Measurements

International Nuclear Information System (INIS)

Strindehag, O.

1971-11-01

The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

Self-Powered Neutron and Gamma Detectors for In-Core Measurements

Energy Technology Data Exchange (ETDEWEB)

Strindehag, O

1971-11-15

The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

New Micromegas detectors in the CAST experiment

International Nuclear Information System (INIS)

Aune, S.; Braeuninger, H.; Dafni, T.; Fanourakis, G.; Ferrer Ribas, E.; Galan Lacarra, J.; Geralis, T.; Giomataris, I.; Iguaz, F.; Irastorza, I.G.; Kousouris, K.; Morales, J.; Mols, J.P.; Papaevangelou, T.; Pivovaroff, M.; Ruz, J.; Soufli, R.; Tomas, A.; Zachariadou, K.

2009-01-01

A low background Micromegas detector was operating at the sunrise side of the CERN Axion Solar Telescope (CAST) experiment during the previous data taking periods (2002-2006). This detector, constructed of low radioactivity materials, operated efficiently and achieved a background level, 5x10 -5 keV -1 cm -2 s -1 , in the 2-7 keV region. This performance was accomplished by exploiting the spatial and energy resolution of the detector as well as the time information contained in the pulse shape of the events. During the second phase of the experiment, the detector at the sunrise was replaced and upgraded by including a shielding. Moreover, the old time projection chamber (TPC) covering the sunset side of the experiment was replaced by two new Micromegas detectors. These detectors belong to the newest generation of Micromegas detectors: 'bulk' and 'microbulk'. Performances and advantages will be presented.

Electronics cooling of Phenix multiplicity and vertex detector

International Nuclear Information System (INIS)

Chen, Z.; Gregory, W.S.

1996-08-01

The Multiplicity and Vertex Detector (MVD) uses silicon strip sensors arranged in two concentric barrels around the beam pipe of the PHENIX detector that will be installed at Brookhaven National Laboratory. Each silicon sensor is connected by a flexible kapton cable to its own front-end electronics printed circuit board that is a multi-chip module or MCM. The MCMs are the main heat source in the system. To maintain the MVD at optimized operational status, the maximum temperature of the multi-chip modules must be below 40 C. Using COSMOS/M HSTAR for the Heat Transfer analysis, a finite element model of a typical MCM plate was created to simulate a 9m/s airflow and 9m/s mixed flow composed of 50% helium and 50% air respectively, with convective heat transfer on both sides of the plate. The results using a mixed flow of helium and air show that the average maximum temperature reached by the MCMs is 37.5 C. The maximum temperature which is represented by the hot spots on the MCM is 39.43 C for the helium and air mixture which meets the design temperature requirement 40 C. To maintain the Multiplicity and Vertex Detector at optimized operational status, the configuration of the plenum chamber, the power dissipated by the silicon chips, the fluid flow velocity and comparison on the MCM design parameters will be discussed

New mixed finite-element methods

International Nuclear Information System (INIS)

Franca, L.P.

1987-01-01

New finite-element methods are proposed for mixed variational formulations. The methods are constructed by adding to the classical Galerkin method various least-squares like terms. The additional terms involve integrals over element interiors, and include mesh-parameter dependent coefficients. The methods are designed to enhance stability. Consistency is achieved in the sense that exact solutions identically satisfy the variational equations.Applied to several problems, simple finite-element interpolations are rendered convergent, including convenient equal-order interpolations generally unstable within the Galerkin approach. The methods are subdivided into two classes according to the manner in which stability is attained: (1) circumventing Babuska-Brezzi condition methods; (2) satisfying Babuska-Brezzi condition methods. Convergence is established for each class of methods. Applications of the first class of methods to Stokes flow and compressible linear elasticity are presented. The second class of methods is applied to the Poisson, Timoshenko beam and incompressible elasticity problems. Numerical results demonstrate the good stability and accuracy of the methods, and confirm the error estimates

Introduction to nonlinear finite element analysis

CERN Document Server

Kim, Nam-Ho

2015-01-01

This book introduces the key concepts of nonlinear finite element analysis procedures. The book explains the fundamental theories of the field and provides instructions on how to apply the concepts to solving practical engineering problems. Instead of covering many nonlinear problems, the book focuses on three representative problems: nonlinear elasticity, elastoplasticity, and contact problems. The book is written independent of any particular software, but tutorials and examples using four commercial programs are included as appendices: ANSYS, NASTRAN, ABAQUS, and MATLAB. In particular, the MATLAB program includes all source codes so that students can develop their own material models, or different algorithms. This book also: ·         Presents clear explanations of nonlinear finite element analysis for elasticity, elastoplasticity, and contact problems ·         Includes many informative examples of nonlinear analyses so that students can clearly understand the nonlinear theory ·    ...

Finite time synchronization of memristor-based Cohen-Grossberg neural networks with mixed delays

OpenAIRE

Chen, Chuan; Li, Lixiang; Peng, Haipeng; Yang, Yixian

2017-01-01

Finite time synchronization, which means synchronization can be achieved in a settling time, is desirable in some practical applications. However, most of the published results on finite time synchronization don't include delays or only include discrete delays. In view of the fact that distributed delays inevitably exist in neural networks, this paper aims to investigate the finite time synchronization of memristor-based Cohen-Grossberg neural networks (MCGNNs) with both discrete delay and di...

Groebner Finite Path Algebras

OpenAIRE

Leamer, Micah J.

2004-01-01

Let K be a field and Q a finite directed multi-graph. In this paper I classify all path algebras KQ and admissible orders with the property that all of their finitely generated ideals have finite Groebner bases. MS

The HERMES recoil detector. Particle identification and determination of detector efficiency of the scintillating fiber tracker

Energy Technology Data Exchange (ETDEWEB)

Lu, Xianguo

2009-11-15

HERMES is a fixed target experiment using the HERA 27.6 GeV polarized electron/positron beams. With the polarized beams and its gas targets, which can be highly polarized, HERMES is dedicated to study the nucleon spin structure. One of its current physics programs is to measure deeply virtual Compton scattering (DVCS). In order to detect the recoiling proton the Recoil Detector was installed in the target region in the winter of 2005, taking data until the HERA-shutdown in the summer of 2007. The Recoil Detector measured energy loss of the traversing particles with its sub-detectors, including the silicon strip detector and the scintillating fiber tracker. This enables particle identification for protons and pions. In this work a systematic particle identification procedure is developed, whose performance is quantified. Another aspect of this work is the determination of the detector efficiency of the scintillating fiber tracker. (orig.)

Calibration of detector efficiency of neutron detector

International Nuclear Information System (INIS)

Guo Hongsheng; He Xijun; Xu Rongkun; Peng Taiping

2001-01-01

BF 3 neutron detector has been set up. Detector efficiency is calibrated by associated particle technique. It is about 3.17 x 10 -4 (1 +- 18%). Neutron yield of neutron generator per pulse (10 7 /pulse) is measured by using the detector

Workshop on detectors for third-generation synchrotron sources: Proceedings

International Nuclear Information System (INIS)

1994-12-01

The aims of the workshop were (1) to acquaint APS users with current R and D being carried out on detectors, (2) to identify new detector systems possible during the next five years, (3) to identify new detectors theoretically possible in the future, (4) to stimulate interactions between user groups and detector developers, and (5) to obtain recommendations from expert panels on technical issues needing resolution. Development of detectors at ESRF, Spring-8, BNL, CERN and LBL are included

Workshop on detectors for third-generation synchrotron sources: Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-01

The aims of the workshop were (1) to acquaint APS users with current R and D being carried out on detectors, (2) to identify new detector systems possible during the next five years, (3) to identify new detectors theoretically possible in the future, (4) to stimulate interactions between user groups and detector developers, and (5) to obtain recommendations from expert panels on technical issues needing resolution. Development of detectors at ESRF, Spring-8, BNL, CERN and LBL are included.

The Gerda Phase II detector assembly

Energy Technology Data Exchange (ETDEWEB)

Bode, Tobias; Schoenert, Stefan [Physik-Department E15, Technische Universitaet Muenchen (Germany); Schwingenheuer, Bernhard [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Collaboration: GERDA-Collaboration

2013-07-01

Phase II of the Gerda (Germanium Detector Array) experiment will continue the search for the neutrinoless double beta decay (0νββ) of {sup 76}Ge. Prerequisites for Phase II are an increased target mass and a reduced background index of < 10 {sup -3} cts/(keV.kg.yr). Major hardware upgrades to achieve these requirements are scheduled for 2013. They include the deployment of a new radio pure low mass detector assembly. The structural properties of available radio-pure materials and reduction of mass necessitate a change of the electrical contacting used to bias and read-out the detectors. The detector assembly design and the favored contacting solution are presented.

Finite time synchronization of memristor-based Cohen-Grossberg neural networks with mixed delays

Science.gov (United States)

2017-01-01

Finite time synchronization, which means synchronization can be achieved in a settling time, is desirable in some practical applications. However, most of the published results on finite time synchronization don’t include delays or only include discrete delays. In view of the fact that distributed delays inevitably exist in neural networks, this paper aims to investigate the finite time synchronization of memristor-based Cohen-Grossberg neural networks (MCGNNs) with both discrete delay and distributed delay (mixed delays). By means of a simple feedback controller and novel finite time synchronization analysis methods, several new criteria are derived to ensure the finite time synchronization of MCGNNs with mixed delays. The obtained criteria are very concise and easy to verify. Numerical simulations are presented to demonstrate the effectiveness of our theoretical results. PMID:28931066

Finite time synchronization of memristor-based Cohen-Grossberg neural networks with mixed delays.

Science.gov (United States)

Chen, Chuan; Li, Lixiang; Peng, Haipeng; Yang, Yixian

2017-01-01

Finite time synchronization, which means synchronization can be achieved in a settling time, is desirable in some practical applications. However, most of the published results on finite time synchronization don't include delays or only include discrete delays. In view of the fact that distributed delays inevitably exist in neural networks, this paper aims to investigate the finite time synchronization of memristor-based Cohen-Grossberg neural networks (MCGNNs) with both discrete delay and distributed delay (mixed delays). By means of a simple feedback controller and novel finite time synchronization analysis methods, several new criteria are derived to ensure the finite time synchronization of MCGNNs with mixed delays. The obtained criteria are very concise and easy to verify. Numerical simulations are presented to demonstrate the effectiveness of our theoretical results.

Finite time synchronization of memristor-based Cohen-Grossberg neural networks with mixed delays.

Directory of Open Access Journals (Sweden)

Chuan Chen

Full Text Available Finite time synchronization, which means synchronization can be achieved in a settling time, is desirable in some practical applications. However, most of the published results on finite time synchronization don't include delays or only include discrete delays. In view of the fact that distributed delays inevitably exist in neural networks, this paper aims to investigate the finite time synchronization of memristor-based Cohen-Grossberg neural networks (MCGNNs with both discrete delay and distributed delay (mixed delays. By means of a simple feedback controller and novel finite time synchronization analysis methods, several new criteria are derived to ensure the finite time synchronization of MCGNNs with mixed delays. The obtained criteria are very concise and easy to verify. Numerical simulations are presented to demonstrate the effectiveness of our theoretical results.

Detector Simulations with DD4hep

Science.gov (United States)

Petrič, M.; Frank, M.; Gaede, F.; Lu, S.; Nikiforou, N.; Sailer, A.

2017-10-01

Detector description is a key component of detector design studies, test beam analyses, and most of particle physics experiments that require the simulation of more and more different detector geometries and event types. This paper describes DD4hep, which is an easy-to-use yet flexible and powerful detector description framework that can be used for detector simulation and also extended to specific needs for a particular working environment. Linear collider detector concepts ILD, SiD and CLICdp as well as detector development collaborations CALICE and FCal have chosen to adopt the DD4hep geometry framework and its DDG4 pathway to Geant4 as its core simulation and reconstruction tools. The DDG4 plugins suite includes a wide variety of input formats, provides access to the Geant4 particle gun or general particles source and allows for handling of Monte Carlo truth information, eg. by linking hits and the primary particle that caused them, which is indispensable for performance and efficiency studies. An extendable array of segmentations and sensitive detectors allows the simulation of a wide variety of detector technologies. This paper shows how DD4hep allows to perform complex Geant4 detector simulations without compiling a single line of additional code by providing a palette of sub-detector components that can be combined and configured via compact XML files. Simulation is controlled either completely via the command line or via simple Python steering files interpreted by a Python executable. It also discusses how additional plugins and extensions can be created to increase the functionality.

LHC luminosity upgrade detector challenges

CERN Multimedia

CERN. Geneva; de Roeck, Albert; Bortoletto, Daniela; Wigmans, Richard; Riegler, Werner; Smith, Wesley H

2006-01-01

LHC luminosity upgrade: detector challenges The upgrade of the LHC machine towards higher luminosity (1035 cm -2s-1) has been studied over the last few years. These studies have investigated scenarios to achieve the increase in peak luminosity by an order of magnitude, as well as the physics potential of such an upgrade and the impact of a machine upgrade on the LHC DETECTORS. This series of lectures will cover the following topics: • Physics motivation and machine scenarios for an order of magnitude increase in the LHC peak luminosity (lecture 1) • Detector challenges including overview of ideas for R&D programs by the LHC experiments: tracking and calorimetry, other new detector developments (lectures 2-4) • Electronics, trigger and data acquisition challenges (lecture 5) Note: the much more ambitious LHC energy upgrade will not be covered

Signal processing for radiation detectors

CERN Document Server

Nakhostin, Mohammad

2018-01-01

This book provides a clear understanding of the principles of signal processing of radiation detectors. It puts great emphasis on the characteristics of pulses from various types of detectors and offers a full overview on the basic concepts required to understand detector signal processing systems and pulse processing techniques. Signal Processing for Radiation Detectors covers all of the important aspects of signal processing, including energy spectroscopy, timing measurements, position-sensing, pulse-shape discrimination, and radiation intensity measurement. The book encompasses a wide range of applications so that readers from different disciplines can benefit from all of the information. In addition, this resource: * Describes both analog and digital techniques of signal processing * Presents a complete compilation of digital pulse processing algorithms * Extrapolates content from more than 700 references covering classic papers as well as those of today * Demonstrates concepts with more than 340 origin...

Numerical analysis of some problems related to the mechanics of pneumatic tires: Finite deformation/rolling contact of a viscoelastic cylinder and finite deformation of cord-reinforced rubber composites

Science.gov (United States)

Oden, J. T.; Becker, E. B.; Lin, T. L.; Hsieh, K. T.

1984-01-01

The formulation and numerical analysis of several problems related to the behavior of pneumatic tires are considered. These problems include the general rolling contact problem of a rubber-like viscoelastic cylinder undergoing finite deformations and the finite deformation of cord-reinforced rubber composites. New finite element models are developed for these problems. Numerical results obtained for several representative cases are presented.

Self powered platinum flux detector application for shutdown system

International Nuclear Information System (INIS)

Su Guoquan

2005-01-01

This article introduce Neutron Flux Detector application in Candu Power Plant, including: design purpose, location in the site, dynamic compensation, differential compensation, detector assembly pressurized with high pure helium etc. And shielding grounding improvement is suggested because of detector signal and setpoint signal noise. (authors)

Operational experience of the ATLAS Pixel detector

CERN Document Server

Hirschbuehl, D; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience of the ATLAS Pixel Detector

CERN Document Server

Marcisovsky, M; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

The Determining Finite Automata Process

Directory of Open Access Journals (Sweden)

M. S. Vinogradova

2017-01-01

Full Text Available The theory of formal languages widely uses finite state automata both in implementation of automata-based approach to programming, and in synthesis of logical control algorithms.To ensure unambiguous operation of the algorithms, the synthesized finite state automata must be deterministic. Within the approach to the synthesis of the mobile robot controls, for example, based on the theory of formal languages, there are problems concerning the construction of various finite automata, but such finite automata, as a rule, will not be deterministic. The algorithm of determinization can be applied to the finite automata, as specified, in various ways. The basic ideas of the algorithm of determinization can be most simply explained using the representations of a finite automaton in the form of a weighted directed graph.The paper deals with finite automata represented as weighted directed graphs, and discusses in detail the procedure for determining the finite automata represented in this way. Gives a detailed description of the algorithm for determining finite automata. A large number of examples illustrate a capability of the determinization algorithm.

Radiation detectors laboratory; Laboratorio de detectores de radiacion

Energy Technology Data Exchange (ETDEWEB)

Ramirez J, F.J. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1997-07-01

The Radiation detectors laboratory was established with the assistance of the International Atomic Energy Agency which gave this the responsibility to provide its services at National and regional level for Latin America and it is located at the ININ. The more expensive and delicate radiation detectors are those made of semiconductor, so it has been put emphasis in the use and repairing of these detectors type. The supplied services by this laboratory are: selection consultant, detectors installation and handling and associated systems. Installation training, preventive and corrective maintenance of detectors and detection systems calibration. (Author)

Summability calculus a comprehensive theory of fractional finite sums

CERN Document Server

Alabdulmohsin, Ibrahim M

2018-01-01

This book develops the foundations of "summability calculus", which is a comprehensive theory of fractional finite sums. It fills an important gap in the literature by unifying and extending disparate historical results. It also presents new material that has not been published before. Importantly, it shows how the study of fractional finite sums benefits from and contributes to many areas of mathematics, such as divergent series, numerical integration, approximation theory, asymptotic methods, special functions, series acceleration, Fourier analysis, the calculus of finite differences, and information theory. As such, it appeals to a wide audience of mathematicians whose interests include the study of special functions, summability theory, analytic number theory, series and sequences, approximation theory, asymptotic expansions, or numerical methods. Richly illustrated, it features chapter summaries, and includes numerous examples and exercises. The content is mostly developed from scratch using only undergr...

Finite-lattice form factors in free-fermion models

International Nuclear Information System (INIS)

Iorgov, N; Lisovyy, O

2011-01-01

We consider the general Z 2 -symmetric free-fermion model on the finite periodic lattice, which includes as special cases the Ising model on the square and triangular lattices and the Z n -symmetric BBS τ (2) -model with n = 2. Translating Kaufman's fermionic approach to diagonalization of Ising-like transfer matrices into the language of Grassmann integrals, we determine the transfer matrix eigenvectors and observe that they coincide with the eigenvectors of a square lattice Ising transfer matrix. This allows us to find exact finite-lattice form factors of spin operators for the statistical model and the associated finite-length quantum chains, of which the most general is equivalent to the XY chain in a transverse field

The ALICE Silicon Pixel Detector System (SPD)

CERN Document Server

Kluge, A; Antinori, Federico; Burns, M; Cali, I A; Campbell, M; Caselle, M; Ceresa, S; Dima, R; Elias, D; Fabris, D; Krivda, Marian; Librizzi, F; Manzari, Vito; Morel, M; Moretto, Sandra; Osmic, F; Pappalardo, G S; Pepato, Adriano; Pulvirenti, A; Riedler, P; Riggi, F; Santoro, R; Stefanini, G; Torcato De Matos, C; Turrisi, R; Tydesjo, H; Viesti, G; PH-EP

2007-01-01

The ALICE silicon pixel detector (SPD) comprises the two innermost layers of the ALICE inner tracker system. The SPD includes 120 detector modules (half-staves) each consisting of 10 ALICE pixel chips bump bonded to two silicon sensors and one multi-chip read-out module. Each pixel chip contains 8192 active cells, so that the total number of pixel cells in the SPD is ≈ 107. The on-detector read-out is based on a multi-chip-module containing 4 ASICs and an optical transceiver module. The constraints on material budget and detector module dimensions are very demanding.

Detector Development for the abBA Experiment.

Science.gov (United States)

Seo, P-N; Bowman, J D; Mitchell, G S; Penttila, S I; Wilburn, W S

2005-01-01

We have developed a new type of field-expansion spectrometer to measure the neutron beta decay correlations (a, b, B, and A). A precision measurement of these correlations places stringent requirements on charged particle detectors. The design employs large area segmented silicon detectors to detect both protons and electrons in coincidence. Other requirements include good energy resolution (electron-backscattering events, and nearly unity efficiency. We report results of testing commercially available surface-barrier silicon detectors for energy resolution and timing performance, and measurement of the dead-layer thickness of ion-implanted silicon detectors with a 3.2 MeV alpha source.

Status of diamond particle detectors

Energy Technology Data Exchange (ETDEWEB)

Krammer, M.; Adam, W.; Friedl, M.; Hrubec, J.; Pernegger, H.; Pernicka, M. [Institut fuer Hochenergiephysik der Oesterr. Akademie d. Wissenschaften, Nikolsdorferg. 18, A-1050 Vienna (Austria); Bauer, C. [MPI fuer Kernphysik, D-69029 Heidelberg (Germany); Berdermann, E.; Stelzer, H. [GSI, Darmstadt (Germany); Bogani, F. [LENS, Florence (Italy); Borchi, E.; Bruzzi, M.; Sciortino, S. [University of Florence, Florence (Italy); Colledani, C.; Dulinski, W.; Husson, D.; LeNormand, F.; Riester, G.L.; Turchetta, R. [LEPSI, CRN Strasbourg (France); Conway, J.; Fish, D.; Schnetzer, S.; Stone, R.; Tesarek, R.; Thomson, G.B.; Walsh, A.M. [Rutgers University, Piscataway, NJ (United States); Dabrowski, W.; Kaplon, J.; Meier, D.; Roe, S.; Rudge, A.; Wedenig, R.; Weilhammer, P. [CERN, CH-1211 Geneva (Switzerland); Delpierre, P.; Hallewell, G. [CPPM, Marseille (France); Deneuville, A.; Cheeraert, E. [LEPES, Grenoble (France); Eijk, B.V.; Hartjes, F. [NIKHEF, Amsterdam (Netherlands); Fallou, A. [CPPM, Marseille (France); Foulon, F. [Centre d' Etudes de Saclay, 91191 Gif-Sur-Yvette (France); Gan, K.K.; Kagan, H.; Kass, R.; Trawick, M.; Zoeller, M. [The Ohio State University, Columbus, OH (United States); Grigoriev, E.; Knoepfle, K.T. [MPI fuer Kernphysik, D-69029 Heidelberg (Germany); Hall-Wilton, R. [Bristol University, Bristol (United Kingdom); Han, S.; Ziock, H. [Los Alamos National Laboratory, Research Division, Los Alamos, NM (United States); Kania, D. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Manfredi, P.F.; Re, V.; Speziali, V. [Universita di Pavia, Dipartimento di Elettronica, 27100 Pavia (Italy); Mishina, M. [FNAL, Batavia, IL (United States); Pan, L.S. [Sandia National Laboratory, Albuquerque, NM (United States); Roff, D.; Tapper, R.J. [Bristol University, Bristol (United Kingdom); Trischuk, W. [University of Toronto, Toronto (Canada)

1998-11-21

To continue the exciting research in the field of particle physics new accelerators and experiments are under construction. In some of these experiments, e.g. ATLAS and CMS at the Large Hadron Collider at CERN or HERA-B at DESY, the detectors have to withstand an extreme environment. The detectors must be radiation hard, provide a very fast signal, and be as thin as possible. The properties of CVD diamond allow to fulfill these requirements and make it an ideal material for the detectors close to the interaction region of these experiments, i.e. the vertex detectors or the inner trackers. The RD42 collaboration is developing diamond detectors for these applications. The program of RD42 includes the improvement of the charge collection properties of CVD diamond, the study of the radiation hardness and the development of low-noise radiation hard readout electronics. An overview of the progress achieved during the last years will be given. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Status of diamond particle detectors

International Nuclear Information System (INIS)

Krammer, M.; Adam, W.; Friedl, M.; Hrubec, J.; Pernegger, H.; Pernicka, M.; Bauer, C.; Berdermann, E.; Stelzer, H.; Bogani, F.; Borchi, E.; Bruzzi, M.; Sciortino, S.; Colledani, C.; Dulinski, W.; Husson, D.; LeNormand, F.; Riester, G.L.; Turchetta, R.; Conway, J.; Fish, D.; Schnetzer, S.; Stone, R.; Tesarek, R.; Thomson, G.B.; Walsh, A.M.; Dabrowski, W.; Kaplon, J.; Meier, D.; Roe, S.; Rudge, A.; Wedenig, R.; Weilhammer, P.; Delpierre, P.; Hallewell, G.; Deneuville, A.; Cheeraert, E.; Eijk, B.V.; Hartjes, F.; Fallou, A.; Foulon, F.; Gan, K.K.; Kagan, H.; Kass, R.; Trawick, M.; Zoeller, M.; Grigoriev, E.; Knoepfle, K.T.; Hall-Wilton, R.; Han, S.; Ziock, H.; Kania, D.; Manfredi, P.F.; Re, V.; Speziali, V.; Mishina, M.; Pan, L.S.; Roff, D.; Tapper, R.J.; Trischuk, W.

1998-01-01

To continue the exciting research in the field of particle physics new accelerators and experiments are under construction. In some of these experiments, e.g. ATLAS and CMS at the Large Hadron Collider at CERN or HERA-B at DESY, the detectors have to withstand an extreme environment. The detectors must be radiation hard, provide a very fast signal, and be as thin as possible. The properties of CVD diamond allow to fulfill these requirements and make it an ideal material for the detectors close to the interaction region of these experiments, i.e. the vertex detectors or the inner trackers. The RD42 collaboration is developing diamond detectors for these applications. The program of RD42 includes the improvement of the charge collection properties of CVD diamond, the study of the radiation hardness and the development of low-noise radiation hard readout electronics. An overview of the progress achieved during the last years will be given. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

A suitable low-order, eight-node tetrahedral finite element for solids

International Nuclear Information System (INIS)

Key, S.W.; Heinstein, M.S.; Stone, C.M.; Mello, F.J.; Blanford, M.L.; Budge, K.G.

1998-03-01

To use the all-tetrahedral mesh generation existing today, the authors have explored the creation of a computationally efficient eight-node tetrahedral finite element (a four-node tetrahedral finite element enriched with four mid-face nodal points). The derivation of the element's gradient operator, studies in obtaining a suitable mass lumping, and the element's performance in applications are presented. In particular they examine the eight-node tetrahedral finite element's behavior in longitudinal plane wave propagation, in transverse cylindrical wave propagation, and in simulating Taylor bar impacts. The element samples only constant strain states and, therefore, has 12 hour-glass modes. In this regard it bears similarities to the eight-node, mean-quadrature hexahedral finite element. Comparisons with the results obtained from the mean-quadrature eight-node hexahedral finite element and the four-node tetrahedral finite element are included. Given automatic all-tetrahedral meshing, the eight-node, constant-strain tetrahedral finite element is a suitable replacement for the eight-node hexahedral finite element in those cases where mesh generation requires an inordinate amount of user intervention and direction to obtain acceptable mesh properties

The radiation environment in the ATLAS inner detector

CERN Document Server

Dawson, I

2000-01-01

The radiation environment in the inner detector has been simulated using the particle transport program FLUKA with a recent description of the ATLAS experiment. Given in this paper are particle fluences and doses at positions relevant to the three inner detector subsystems; the Pixel, SCT and TRT detectors. In addition, studies are reported on in which (1) information concerning the optimization of the inner detector neutron-moderators is obtained and (2) the impact of including additional vacuum-equipment material is assessed. (19 refs).

Numerical experiment on finite element method for matching data

International Nuclear Information System (INIS)

Tokuda, Shinji; Kumakura, Toshimasa; Yoshimura, Koichi.

1993-03-01

Numerical experiments are presented on the finite element method by Pletzer-Dewar for matching data of an ordinary differential equation with regular singular points by using model equation. Matching data play an important role in nonideal MHD stability analysis of a magnetically confined plasma. In the Pletzer-Dewar method, the Frobenius series for the 'big solution', the fundamental solution which is not square-integrable at the regular singular point, is prescribed. The experiments include studies of the convergence rate of the matching data obtained by the finite element method and of the effect on the results of computation by truncating the Frobenius series at finite terms. It is shown from the present study that the finite element method is an effective method for obtaining the matching data with high accuracy. (author)

Detector and System Developments for LHC Detector Upgrades

CERN Document Server

Mandelli, Beatrice; Guida, Roberto; Rohne, Ole; Stapnes, Steinar

2015-05-12

The future Large Hadron Collider (LHC) Physics program and the consequent improvement of the LHC accelerator performance set important challenges to all detector systems. This PhD thesis delineates the studies and strategies adopted to improve two different types of detectors: the replacement of precision trackers with ever increasingly performing silicon detectors, and the improvement of large gaseous detector systems by optimizing their gas mixtures and operation modes. Within the LHC tracker upgrade programs, the ATLAS Insertable B-layer (IBL) is the first major upgrade of a silicon-pixel detector. Indeed the overall ATLAS Pixel Detector performance is expected to degrade with the increase of luminosity and the IBL will recover the performance by adding a fourth innermost layer. The IBL Detector makes use of new pixel and front-end electronics technologies as well as a novel thermal management approach and light support and service structures. These innovations required complex developments and Quality Ass...

Detector Unit

CERN Multimedia

1960-01-01

Original detector unit of the Instituut voor Kernfysisch Onderzoek (IKO) BOL project. This detector unit shows that silicon detectors for nuclear physics particle detection were already developed and in use in the 1960's in Amsterdam. Also the idea of putting 'strips' onto the silicon for high spatial resolution of a particle's impact on the detector were implemented in the BOL project which used 64 of these detector units. The IKO BOL project with its silicon particle detectors was designed, built and operated from 1965 to roughly 1977. Detector Unit of the BOL project: These detectors, notably the ‘checkerboard detector’, were developed during the years 1964-1968 in Amsterdam, The Netherlands, by the Natuurkundig Laboratorium of the N.V. Philips Gloeilampen Fabrieken. This was done in close collaboration with the Instituut voor Kernfysisch Onderzoek (IKO) where the read-out electronics for their use in the BOL Project was developed and produced.

Finite Element Modeling and Analysis of Nonlinear Impact and Frictional Motion Responses Including Fluid—Structure Coupling Effects

Directory of Open Access Journals (Sweden)

Yong Zhao

1997-01-01

Full Text Available A nonlinear three dimensional (3D single rack model and a nonlinear 3D whole pool multi-rack model are developed for the spent fuel storage racks of a nuclear power plant (NPP to determine impacts and frictional motion responses when subjected to 3D excitations from the supporting building floor. The submerged free standing rack system and surrounding water are coupled due to hydrodynamic fluid-structure interaction (FSI using potential theory. The models developed have features that allow consideration of geometric and material nonlinearities including (1 the impacts of fuel assemblies to rack cells, a rack to adjacent racks or pool walls, and rack support legs to the pool floor; (2 the hydrodynamic coupling of fuel assemblies with their storing racks, and of a rack with adjacent racks, pool walls, and the pool floor; and (3 the dynamic motion behavior of rocking, twisting, and frictional sliding of rack modules. Using these models 3D nonlinear time history dynamic analyses are performed per the U.S. Nuclear Regulatory Commission (USNRC criteria. Since few such modeling, analyses, and results using both the 3D single and whole pool multiple rack models are available in the literature, this paper emphasizes description of modeling and analysis techniques using the SOLVIA general purpose nonlinear finite element code. Typical response results with different Coulomb friction coefficients are presented and discussed.

Optimization of thermal systems based on finite-time thermodynamics and thermoeconomics

Energy Technology Data Exchange (ETDEWEB)

Durmayaz, A. [Istanbul Technical University (Turkey). Department of Mechanical Engineering; Sogut, O.S. [Istanbul Technical University, Maslak (Turkey). Department of Naval Architecture and Ocean Engineering; Sahin, B. [Yildiz Technical University, Besiktas, Istanbul (Turkey). Department of Naval Architecture; Yavuz, H. [Istanbul Technical University, Maslak (Turkey). Institute of Energy

2004-07-01

The irreversibilities originating from finite-time and finite-size constraints are important in the real thermal system optimization. Since classical thermodynamic analysis based on thermodynamic equilibrium do not consider these constraints directly, it is necessary to consider the energy transfer between the system and its surroundings in the rate form. Finite-time thermodynamics provides a fundamental starting point for the optimization of real thermal systems including the fundamental concepts of heat transfer and fluid mechanics to classical thermodynamics. In this study, optimization studies of thermal systems, that consider various objective functions, based on finite-time thermodynamics and thermoeconomics are reviewed. (author)

Finite-size scaling a collection of reprints

CERN Document Server

1988-01-01

Over the past few years, finite-size scaling has become an increasingly important tool in studies of critical systems. This is partly due to an increased understanding of finite-size effects by analytical means, and partly due to our ability to treat larger systems with large computers. The aim of this volume was to collect those papers which have been important for this progress and which illustrate novel applications of the method. The emphasis has been placed on relatively recent developments, including the use of the &egr;-expansion and of conformal methods.

Development of sodium leak detectors for PFBR

International Nuclear Information System (INIS)

Sylvia, J.I.; Rao, P. Vijayamohana; Babu, B.; Madhusoodanan, K.; Rajan, K.K.

2012-01-01

Highlights: ► Sodium leak detection system developed for PFBR using diverse principle. ► Miniature, remotely locatable diverse leak detector developed for Main Vessel. ► Mutual inductance type leak detectors designed and adapted for different locations. ► Sodium Ionisation detectors used for area monitoring. ► Crosswire type leak detector designed, developed and tested. - Abstract: The 500 MWe Prototype Fast Breeder Reactor (PFBR) is under advanced stage of construction at Kalpakkam near Chennai in India. The wide and high operating temperature, highly chemically active nature of sodium and its reaction with air make the sodium instrumentation complex over the conventional instrumentation. Over the years, traditional instruments such as wire type leak detectors, spark plug type leak detectors were developed and used in different sodium systems. The redundant and diverse leak detection method calls for development of special instrumentation for sodium systems which include sodium ionization (leak) detector for detecting minute sodium leak in addition to those systems based on mutual inductance principle. For detection of sodium leak from reactor Main Vessel (MV), diverse methods are used such as miniature, remotely locatable, Mutual Inductance type Leak Detector(MILD) and specially modified spark plug type leak detector. The design of MILD is suitably modified for detecting leak in double wall pipes and Diverse Safety Rod drive Mechanism (DSRDM). Steam/water leak in steam generator produces hydrogen and leads to high pressure and temperature in the system. Rupture disc is used as a safety device which punctures itself due to sudden pressure rise. To detect the discharge of sodium and its reaction products at the downstream of the rupture disc due to bursting of the rupture disc, cross wire type leak detector has been designed, developed and tested. The selection of the leak detection system depends on the location where leak has to be detected. This paper

A review of the developments of radioxenon detectors for nuclear explosion monitoring

Energy Technology Data Exchange (ETDEWEB)

Sivels, Ciara B.; McIntyre, Justin I.; Bowyer, Theodore W.; Kalinowski, Martin B.; Pozzi, Sara A.

2017-09-27

Developments in radioxenon monitoring since the implementation of the International Monitoring System are reviewed with emphasis on the most current technologies to improve detector sensitivity and resolution. The nuclear detectors reviewed include combinations of plastic and NaI(Tl) detectors, high purity germanium detectors, silicon detectors, and phoswich detectors. The minimum detectable activity and calibration methods for the various detectors are also discussed.

The Silicon Ministrip Detector of the DELPHI Very Forward Tracker

CERN Document Server

AUTHOR|(CDS)2067985

1996-01-01

The subject of this work is the design, test and construction of a new silicon tracking detector for the extreme forward region of the DELPHI experiment at LEP. I joined the Very Forward Tracker (VFT) Ministrip group in 1993, at a time when the upgrade of the DELPHI tracking system was proposed. My first task was to participate in the design of the ministrip detector for the VFT. This included the optimisation of the detector layout in simulations and the study of prototype detectors in the testbeam. In 1994 I became responsible for the tests and assembly' of the VFT ministrip detector at CERN. The main focus of my work was the study of the performance of a large variety of detectors in beam tests. This included the preparation of the test setup, the tests of different detectors and the analysis of the measurements. With these measurements it is possible to compare the advantages and disadvantages of various new layouts for large pitch silicon strip detectors. In particular the signal response and spatial res...

A finite landscape?

International Nuclear Information System (INIS)

Acharya, B.S.; Douglas, M.R.

2006-06-01

We present evidence that the number of string/M theory vacua consistent with experiments is finite. We do this both by explicit analysis of infinite sequences of vacua and by applying various mathematical finiteness theorems. (author)

Fractional finite Fourier transform.

Science.gov (United States)

Khare, Kedar; George, Nicholas

2004-07-01

We show that a fractional version of the finite Fourier transform may be defined by using prolate spheroidal wave functions of order zero. The transform is linear and additive in its index and asymptotically goes over to Namias's definition of the fractional Fourier transform. As a special case of this definition, it is shown that the finite Fourier transform may be inverted by using information over a finite range of frequencies in Fourier space, the inversion being sensitive to noise. Numerical illustrations for both forward (fractional) and inverse finite transforms are provided.

Monolithic active pixel radiation detector with shielding techniques

Energy Technology Data Exchange (ETDEWEB)

Deptuch, Grzegorz W.

2018-03-20

A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

The finite-difference and finite-element modeling of seismic wave propagation and earthquake motion

International Nuclear Information System (INIS)

Moszo, P.; Kristek, J.; Galis, M.; Pazak, P.; Balazovijech, M.

2006-01-01

Numerical modeling of seismic wave propagation and earthquake motion is an irreplaceable tool in investigation of the Earth's structure, processes in the Earth, and particularly earthquake phenomena. Among various numerical methods, the finite-difference method is the dominant method in the modeling of earthquake motion. Moreover, it is becoming more important in the seismic exploration and structural modeling. At the same time we are convinced that the best time of the finite-difference method in seismology is in the future. This monograph provides tutorial and detailed introduction to the application of the finite-difference, finite-element, and hybrid finite-difference-finite-element methods to the modeling of seismic wave propagation and earthquake motion. The text does not cover all topics and aspects of the methods. We focus on those to which we have contributed. (Author)

Spectral and spatial resolution properties of photon counting X-ray detectors like the Medipix-Detector

International Nuclear Information System (INIS)

Korn, A.

2007-01-01

The Medipix detector is a hybrid photon counting X-ray detector, consisting of an ASIC and a semiconducting layer as the sensor. This makes the Medipix a direct converting detector. A special feature of the Medipix is a signal processing circuit in every single pixel. This circuit amplifies the input signal triggered by a photon and then transforms the pulse into a digital signal. This early stage digitalisation is one of the main advantages of the detector, since no dark currents are integrated into the signal. Furthermore, the energy information of each single photon is partly preserved. The high number of pixels lends the detector a wide dynamic range, starting from single counts up to a rate of 1010 photons per cm2 and second. Apart from the many advantages, there are still some problems with the detector. Some effects lead to a deterioration of the energy resolution as well as the spatial resolution. The main reasons for this are two effects occuring in the detector, charge sharing and backscattering inside the detector. This study investigates the influence of those two effects on both the energy and spatial resolution. The physical causes of these effects are delineated and their impact on the detector output is examined. In contrast to high energy photon detectors, the repulsion of the charge carriers drifting inside the sensor must not be neglected in a detailed model of X-ray detectors with an energy range of 5 keV-200 keV. For the simulation of the Medipix using Monte Carlo simulations, the software ROSI was augmented. The added features allow a detailed simulation of the charge distribution, using the relevant physical effects that alter the distribution width during the drift towards the sensor electrodes as well further influences on the detector output, including electronical noise, threshold noise or the geometry of the detector. The measured energy and spatial resolution of several different models of Medipix is compared to the simulated

Finite-size scaling of survival probability in branching processes.

Science.gov (United States)

Garcia-Millan, Rosalba; Font-Clos, Francesc; Corral, Álvaro

2015-04-01

Branching processes pervade many models in statistical physics. We investigate the survival probability of a Galton-Watson branching process after a finite number of generations. We derive analytically the existence of finite-size scaling for the survival probability as a function of the control parameter and the maximum number of generations, obtaining the critical exponents as well as the exact scaling function, which is G(y)=2ye(y)/(e(y)-1), with y the rescaled distance to the critical point. Our findings are valid for any branching process of the Galton-Watson type, independently of the distribution of the number of offspring, provided its variance is finite. This proves the universal behavior of the finite-size effects in branching processes, including the universality of the metric factors. The direct relation to mean-field percolation is also discussed.

High-Order Entropy Stable Finite Difference Schemes for Nonlinear Conservation Laws: Finite Domains

Science.gov (United States)

Fisher, Travis C.; Carpenter, Mark H.

2013-01-01

Developing stable and robust high-order finite difference schemes requires mathematical formalism and appropriate methods of analysis. In this work, nonlinear entropy stability is used to derive provably stable high-order finite difference methods with formal boundary closures for conservation laws. Particular emphasis is placed on the entropy stability of the compressible Navier-Stokes equations. A newly derived entropy stable weighted essentially non-oscillatory finite difference method is used to simulate problems with shocks and a conservative, entropy stable, narrow-stencil finite difference approach is used to approximate viscous terms.

A novel method for assessing position-sensitive detector performance

International Nuclear Information System (INIS)

Clinthorne, N.H.; Rogers, W.L.; Shao, L.; Hero, A.O. III; Koral, K.F.

1989-01-01

A marked point process model of a position-sensitive detector is developed which includes the effects of detector efficiency, spatial response, energy response, and source statistics. The average mutual information between the incident distribution of γ rays and the detector response is derived and used as a performance index for detector optimization. A brief example is presented which uses this figure-of-merit for optimization of light guide dimensions for a modular scintillation camera

High precision detector robot arm system

Science.gov (United States)

Shu, Deming; Chu, Yong

2017-01-31

A method and high precision robot arm system are provided, for example, for X-ray nanodiffraction with an X-ray nanoprobe. The robot arm system includes duo-vertical-stages and a kinematic linkage system. A two-dimensional (2D) vertical plane ultra-precision robot arm supporting an X-ray detector provides positioning and manipulating of the X-ray detector. A vertical support for the 2D vertical plane robot arm includes spaced apart rails respectively engaging a first bearing structure and a second bearing structure carried by the 2D vertical plane robot arm.

High performance visual display for HENP detectors

International Nuclear Information System (INIS)

McGuigan, Michael; Smith, Gordon; Spiletic, John; Fine, Valeri; Nevski, Pavel

2001-01-01

A high end visual display for High Energy Nuclear Physics (HENP) detectors is necessary because of the sheer size and complexity of the detector. For BNL this display will be of special interest because of STAR and ATLAS. To load, rotate, query, and debug simulation code with a modern detector simply takes too long even on a powerful work station. To visualize the HENP detectors with maximal performance we have developed software with the following characteristics. We develop a visual display of HENP detectors on BNL multiprocessor visualization server at multiple level of detail. We work with general and generic detector framework consistent with ROOT, GAUDI etc, to avoid conflicting with the many graphic development groups associated with specific detectors like STAR and ATLAS. We develop advanced OpenGL features such as transparency and polarized stereoscopy. We enable collaborative viewing of detector and events by directly running the analysis in BNL stereoscopic theatre. We construct enhanced interactive control, including the ability to slice, search and mark areas of the detector. We incorporate the ability to make a high quality still image of a view of the detector and the ability to generate animations and a fly through of the detector and output these to MPEG or VRML models. We develop data compression hardware and software so that remote interactive visualization will be possible among dispersed collaborators. We obtain real time visual display for events accumulated during simulations

Simple classical model for Fano statistics in radiation detectors

Energy Technology Data Exchange (ETDEWEB)

Jordan, David V. [Pacific Northwest National Laboratory, National Security Division - Radiological and Chemical Sciences Group PO Box 999, Richland, WA 99352 (United States)], E-mail: David.Jordan@pnl.gov; Renholds, Andrea S.; Jaffe, John E.; Anderson, Kevin K.; Rene Corrales, L.; Peurrung, Anthony J. [Pacific Northwest National Laboratory, National Security Division - Radiological and Chemical Sciences Group PO Box 999, Richland, WA 99352 (United States)

2008-02-01

A simple classical model that captures the essential statistics of energy partitioning processes involved in the creation of information carriers (ICs) in radiation detectors is presented. The model pictures IC formation from a fixed amount of deposited energy in terms of the statistically analogous process of successively sampling water from a large, finite-volume container ('bathtub') with a small dipping implement ('shot or whiskey glass'). The model exhibits sub-Poisson variance in the distribution of the number of ICs generated (the 'Fano effect'). Elementary statistical analysis of the model clarifies the role of energy conservation in producing the Fano effect and yields Fano's prescription for computing the relative variance of the IC number distribution in terms of the mean and variance of the underlying, single-IC energy distribution. The partitioning model is applied to the development of the impact ionization cascade in semiconductor radiation detectors. It is shown that, in tandem with simple assumptions regarding the distribution of energies required to create an (electron, hole) pair, the model yields an energy-independent Fano factor of 0.083, in accord with the lower end of the range of literature values reported for silicon and high-purity germanium. The utility of this simple picture as a diagnostic tool for guiding or constraining more detailed, 'microscopic' physical models of detector material response to ionizing radiation is discussed.

Fast-timing methods for semiconductor detectors

International Nuclear Information System (INIS)

Spieler, H.

1982-03-01

The basic parameters are discussed which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter

Radon chamber for soil gas detectors

International Nuclear Information System (INIS)

Andersson, P.

1987-01-01

Swedish Geological Co (SGAB) has designed and constructed a chamber for the calibration of detectors and instruments intended for the measurement of radon-222 in soil gas. In the chamber radon detectors may be exposed in a model environment which simulates ground conditions with respect to radon concentration, temperature and humidity. Also included in the research project is the development of methods for calibration procedures, together with test measurements. In general, these measurements indicate that the radon detectors tested are sufficiently accurate and reliable for radon measurements in Swedish soils if they are calibrated in an environment which simulates ground conditions. (orig./HP)

NA62 cavern and sub-detectors 2017

CERN Multimedia

Graham, Connor

2017-01-01

The NA62 cavern, with the completed detector, during breaks in data taking in July 2017. Pictures from 05-07-17 by Dan Protopopescu and pictures from 08-07-17 by Connor Graham (Both Glasgow-affiliated). Includes pictures of the whole experiment, safety systems and sub-detector elements.

A suitable low-order, eight-node tetrahedral finite element for solids

Energy Technology Data Exchange (ETDEWEB)

Key, S.W.; Heinstein, M.S.; Stone, C.M.; Mello, F.J.; Blanford, M.L.; Budge, K.G.

1998-03-01

To use the all-tetrahedral mesh generation existing today, the authors have explored the creation of a computationally efficient eight-node tetrahedral finite element (a four-node tetrahedral finite element enriched with four mid-face nodal points). The derivation of the element`s gradient operator, studies in obtaining a suitable mass lumping, and the element`s performance in applications are presented. In particular they examine the eight-node tetrahedral finite element`s behavior in longitudinal plane wave propagation, in transverse cylindrical wave propagation, and in simulating Taylor bar impacts. The element samples only constant strain states and, therefore, has 12 hour-glass modes. In this regard it bears similarities to the eight-node, mean-quadrature hexahedral finite element. Comparisons with the results obtained from the mean-quadrature eight-node hexahedral finite element and the four-node tetrahedral finite element are included. Given automatic all-tetrahedral meshing, the eight-node, constant-strain tetrahedral finite element is a suitable replacement for the eight-node hexahedral finite element in those cases where mesh generation requires an inordinate amount of user intervention and direction to obtain acceptable mesh properties.

Inelastic analysis of finite length and depth cracked tubes

International Nuclear Information System (INIS)

Reich, M.; Gardner, D.; Prachuktam, S.; Chang, T.Y.

1977-01-01

Steam generator tube failure can at times result in reactor safety problems and subsequent premature reactor shutdown. This paper concerns itself with the prediction of the failure pressures for typical PWR steam generator tubes with longitudinal finite length and finite depth cracks. Only local plastic overload failure is considered since the material is non-notch sensitive. Non-linear finite element analyses are carried out to determine the burst pressures of steam generator tubes containing longitudinal cracks located on the outer surface of the tubes. The non-linearities considered herein include elastic-plastic material behaviour and large deformations. A non-proprietary general purpose non-linear finite element program, NFAP was adopted for the analysis. Due to the asymmetric nature of the cracks, two-dimensional as well as three-dimensional finite element analyses, were performed. The analysis clearly shows that for short cracks axial effects play a significant role. For long cracks, they are not important since two-dimensional conditions predominate and failure is governed by circumferential or hoop stress conditions. (Auth.)

On measurement of the acoustic nonlinearity parameter using the finite amplitude insertion substitution (FAIS) technique

Science.gov (United States)

Zeqiri, Bajram; Cook, Ashley; Rétat, Lise; Civale, John; ter Haar, Gail

2015-04-01

The acoustic nonlinearity parameter, B/A, is an important parameter which defines the way a propagating finite amplitude acoustic wave progressively distorts when travelling through any medium. One measurement technique used to determine its value is the finite amplitude insertion substitution (FAIS) method which has been applied to a range of liquid, tissue and tissue-like media. Importantly, in terms of the achievable measurement uncertainties, it is a relative technique. This paper presents a detailed study of the method, employing a number of novel features. The first of these is the use of a large area membrane hydrophone (30 mm aperture) which is used to record the plane-wave component of the acoustic field. This reduces the influence of diffraction on measurements, enabling studies to be carried out within the transducer near-field, with the interrogating transducer, test cell and detector positioned close to one another, an attribute which assists in controlling errors arising from nonlinear distortion in any intervening water path. The second feature is the development of a model which estimates the influence of finite-amplitude distortion as the acoustic wave travels from the rear surface of the test cell to the detector. It is demonstrated that this can lead to a significant systematic error in B/A measurement whose magnitude and direction depends on the acoustic property contrast between the test material and the water-filled equivalent cell. Good qualitative agreement between the model and experiment is reported. B/A measurements are reported undertaken at (20 ± 0.5) °C for two fluids commonly employed as reference materials within the technical literature: Corn Oil and Ethylene Glycol. Samples of an IEC standardised agar-based tissue-mimicking material were also measured. A systematic assessment of measurement uncertainties is presented giving expanded uncertainties in the range ±7% to ±14%, expressed at a confidence level close to 95

Behaviour of aged and new flux detectors in Darlington reactors

Energy Technology Data Exchange (ETDEWEB)

Banica, C.; Foster, M., E-mail: Constantin.Banica@OPG.com [Ontario Power Generation, Darlington Nuclear, Bowmanville, Ontario (Canada)

2013-07-01

In-core neutron flux detectors are used for protective and safety functions in the Darlington NGS 'A' CANDU reactors. This paper presents new observations regarding the aging of flux detectors, including response to fuelling, response to unit shutdown and indicators of detector noise. Comparisons of detector signals before and after replacement confirm previous assumptions about aging effects. (author)

Calculating and optimizing inter-electrode capacitances of charge division microchannel plate detectors

Energy Technology Data Exchange (ETDEWEB)

Xing, Yan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Bo, E-mail: chenb@ciomp.ac.cn [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Zhang, Hong-Ji; Wang, Hai-Feng; He, Ling-Ping [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Jin, Fang-Yuan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2016-04-01

Based on the principle of charge division microchannel plate detectors, the inter-electrode capacitances of charge division anodes which are related to electronic noise of the charge sensitive amplifier and crosstalk effect of the anode are presented. Under all the requirements of charge division microchannel plate detectors such as the imaging linearity and spatial resolution, decreasing the inter-electrode capacitances is one way to improve the imaging performance. In this paper, we illustrate the simulation process of calculating the inter-electrode capacitances. Moreover, a Wedge and Strip (WSZ) anode is fabricated with the picosecond laser micromachining process. Comparing the simulated capacitances and measured capacitances, the three-dimensional finite element method is proved to be valid. Furthermore, by adjusting the design parameters of the anode, the effects of the substrate permittivity, insulation width and the size of pitch on the inter-electrode capacitances have been analysed. The structure of the charge division anode has been optimized based on the simulation data.

Operational experience with the ATLAS Pixel Detector

CERN Document Server

Ince, T; The ATLAS collaboration

2012-01-01

The ATLAS Pixel Detector is the innermost element of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

COMMISSIONING AND DETECTOR PERFORMANCE GROUPS

CERN Document Server

T. Camporesi

The major progress made during the last months has been in the consolidation of services for the +endcaps and three barrel wheels (YB+2, YB+1 and YB0): all subdetectors have now final power connections (including Detector Safety protection), the gas systems have been commissioned for all gas detectors (the recirculation is not yet activated for the RPC though) and detector cooling has also been commissioned. Their integration with final services is the necessary condition for being able to operate larger fractions the detector. Recent weeks have seen full HCAL, more than 50% of EB and full wheels of DTs and CSC being operated using final services. This has not yet translated into major progress of global integration due to major interruptions of central services, which have not allowed the necessary debugging and commissioning time to all the subdetec¬tors and central activities like DAQ and trigger. Moreover the running in of the final central services has introduced instabilities related to the co...

Detector module for gas monitor

International Nuclear Information System (INIS)

1980-01-01

The invention relates to radioactive source detector module for use in a gas monitor. It is adapted to contain the source and other detector components to allow sealed coupling of those components with other portions of the gas monitor. It is particularly concerned with the use of radioactive materials used as electron sources in gas monitors. The module is used to detect changes in electron flow caused by partial absorption of the electron capture gas flowing between two electrodes. The assembly includes a gas flow source, a gas receiver and an electronic assembly for receiving a signal from the detector. The radioactive source and electrodes are housed so that they are connected to the gas flow source so as to prevent accidental or undesired disconnection. It is designed so that the detector module may be removed or replaced into the gas monitor assemblies by untrained personnel so as to prevent exposure to the radioactive material. Full details are given. (U.K.)

Evaluation of detector efficiency through GUPIXWIN H value

Science.gov (United States)

Fernandes, F.; Niekraszewicz, L. A. B.; Amaral, L.; Dias, J. F.

2018-02-01

In this work we explore the capabilities of the GUPIXWIN software to introduce a simple and straightforward way to obtain the efficiency of X-ray detectors commonly used in PIXE (Particle-Induced X-ray Emission) experiments. To that end, all geometrical parameters of the experimental setup including details of the detector used to detect X-rays must be well known in order to calculate the solid angle subtended by the detector's crystal. The solid angle is calculated through a Monte Carlo program developed by Taylor and co-workers which is included in the GUPIXWIN software package. The H values are obtained from a set of experiments using standards. The results for the intrinsic efficiency of a Si(Li) detector are in good agreement with those obtained from Monte Carlo calculations and are compatible with a simple exponential law.

Silicon detectors

International Nuclear Information System (INIS)

Klanner, R.

1984-08-01

The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

Overview of DRS uncooled VOx infrared detector development

Science.gov (United States)

Li, Chuan; Han, C. J.; Skidmore, George

2011-06-01

Significant progress has been made over the past decade on uncooled focal plane array technologies and production capabilities. The detector pixel dimensions have continually decreased with an increase in pixel performance making large format, high-density array products affordable. In turn, this has resulted in the proliferation of uncooled IR detectors in commercial and military markets. Presently, uncooled detectors are widely used in firefighting, surveillance, industrial process monitoring, machine vision, and medical applications. Within the military arena, uncooled detectors are ubiquitous in Army soldier systems such as weapon sights, driver's viewers, and helmet-mounted sights. Uncooled detectors are also employed in airborne and ground surveillance sensors including unmanned aerial vehicles and robot vehicles.

Finite Boltzmann schemes

NARCIS (Netherlands)

Sman, van der R.G.M.

2006-01-01

In the special case of relaxation parameter = 1 lattice Boltzmann schemes for (convection) diffusion and fluid flow are equivalent to finite difference/volume (FD) schemes, and are thus coined finite Boltzmann (FB) schemes. We show that the equivalence is inherent to the homology of the

Development of a partitioned finite volume-finite element fluid-structure interaction scheme for strongly-coupled problems

CSIR Research Space (South Africa)

Suliman, Ridhwaan

2012-07-01

Full Text Available -linear deformations are accounted for. As will be demonstrated, the finite volume approach exhibits similar disad- vantages to the linear Q4 finite element formulation when undergoing bending. An enhanced finite volume approach is discussed and compared with finite...

Development of a detector control system for the serially powered ATLAS pixel detector at the HL-LHC

Energy Technology Data Exchange (ETDEWEB)

Puellen, Lukas

2015-02-10

In the years around 2020 the LHC will be upgraded to the HL-LHC. In terms of this upgrade, the ATLAS detector will also be upgraded. This also includes the pixel detector, the innermost of the sub-detectors in ATLAS. Thereby the powering concept of the pixel detector will be changed to reduce the material budget of the detector. From individual powering of each detector module, the concept changes to serial powering, where all modules of a powering group are connected in series. This change makes the development of a new detector control system (DCS) mandatory. Therefore, a new concept for the ATLAS pixel DCS is being developed at the University of Wuppertal. This concept is split into three paths: a safety path, a control path, and a diagnostics path. The safety path is a hard wired interlock system. The concept of this system will not differ significantly, compared to the interlock system of the current detector. The diagnostics path is embedded into the optical data read-out of the detector and will be used for detector tuning with high precision and granularity. The control path supervises the detector and provides a user interface to the hardware components. A concept for this path, including a prototype and proof-of-principle studies, has been developed in terms of this thesis. The control path consists of the DCS network, a read-out and controlling topology created by two types of ASICs: the DCS controller and the DCS chip. These ASICs measure and control all values, necessary for a safe detector operation in situ. This reduces the number of required cables and hence the material budget of the system. For the communication between these ASICs, two very fault tolerant bus protocols have been chosen: CAN bus carries data from the DCS computers, outside of the detector, to the DCS controllers at the edge of the pixel detector. For the communication between the DCS controller and the DCS chip, which is located close to each detector module, an enhanced I2C

Development of a detector control system for the serially powered ATLAS pixel detector at the HL-LHC

International Nuclear Information System (INIS)

Puellen, Lukas

2015-01-01

In the years around 2020 the LHC will be upgraded to the HL-LHC. In terms of this upgrade, the ATLAS detector will also be upgraded. This also includes the pixel detector, the innermost of the sub-detectors in ATLAS. Thereby the powering concept of the pixel detector will be changed to reduce the material budget of the detector. From individual powering of each detector module, the concept changes to serial powering, where all modules of a powering group are connected in series. This change makes the development of a new detector control system (DCS) mandatory. Therefore, a new concept for the ATLAS pixel DCS is being developed at the University of Wuppertal. This concept is split into three paths: a safety path, a control path, and a diagnostics path. The safety path is a hard wired interlock system. The concept of this system will not differ significantly, compared to the interlock system of the current detector. The diagnostics path is embedded into the optical data read-out of the detector and will be used for detector tuning with high precision and granularity. The control path supervises the detector and provides a user interface to the hardware components. A concept for this path, including a prototype and proof-of-principle studies, has been developed in terms of this thesis. The control path consists of the DCS network, a read-out and controlling topology created by two types of ASICs: the DCS controller and the DCS chip. These ASICs measure and control all values, necessary for a safe detector operation in situ. This reduces the number of required cables and hence the material budget of the system. For the communication between these ASICs, two very fault tolerant bus protocols have been chosen: CAN bus carries data from the DCS computers, outside of the detector, to the DCS controllers at the edge of the pixel detector. For the communication between the DCS controller and the DCS chip, which is located close to each detector module, an enhanced I2C

Rapid pulse annealing of CdZnTe detectors for reducing electronic noise

Science.gov (United States)

Voss, Lars; Conway, Adam; Nelson, Art; Nikolic, Rebecca J.; Payne, Stephen A.; Swanberg, Jr., Erik Lars

2018-05-01

A combination of doping, rapid pulsed optical and/or thermal annealing, and unique detector structure reduces or eliminates sources of electronic noise in a CdZnTe (CZT) detector. According to several embodiments, methods of forming a detector exhibiting minimal electronic noise include: pulse-annealing at least one surface of a detector comprising CZT for one or more pulses, each pulse having a duration of .about.0.1 seconds or less. The at least one surface may optionally be ion-implanted. In another embodiment, a CZT detector includes a detector surface with two or more electrodes operating at different electric potentials and coupled to the detector surface; and one or more ion-implanted CZT surfaces on or in the detector surface, each of the one or more ion-implanted CZT surfaces being independently connected to one of the two or more electrodes and the surface of the detector. At least two of the ion-implanted surfaces are in electrical contact.

Finite quantum field theories

International Nuclear Information System (INIS)

Lucha, W.; Neufeld, H.

1986-01-01

We investigate the relation between finiteness of a four-dimensional quantum field theory and global supersymmetry. To this end we consider the most general quantum field theory and analyse the finiteness conditions resulting from the requirement of the absence of divergent contributions to the renormalizations of the parameters of the theory. In addition to the gauge bosons, both fermions and scalar bosons turn out to be a necessary ingredient in a non-trivial finite gauge theory. In all cases discussed, the supersymmetric theory restricted by two well-known constraints on the dimensionless couplings proves to be the unique solution of the finiteness conditions. (Author)

Mobility and powering of large detectors. Moving large detectors

International Nuclear Information System (INIS)

Thompson, J.

1977-01-01

The possibility is considered of moving large lepton detectors at ISABELLE for readying new experiments, detector modifications, and detector repair. A large annex (approximately 25 m x 25 m) would be built adjacent to the Lepton Hall separated from the Lepton Hall by a wall of concrete 11 m high x 12 m wide (for clearance of the detector) and approximately 3 m thick (for radiation shielding). A large pad would support the detector, the door, the cryogenic support system and the counting house. In removing the detector from the beam hall, one would push the pad into the annex, add a dummy beam pipe, bake out the beam pipe, and restack and position the wall on a small pad at the door. The beam could then operate again while experimenters could work on the large detector in the annex. A consideration and rough price estimate of various questions and proposed solutions are given

Neutron detectors for the ESS diffractometers

Czech Academy of Sciences Publication Activity Database

Stefanescu, I.; Christensen, M.; Fenske, J.; Hall-Wilton, R.; Henry, P. F.; Kirstein, O.; Muller, M.; Nowak, G.; Pooley, D.; Raspino, D.; Rhodes, N.; Šaroun, Jan; Schefer, J.; Schooneveld, E.; Sykora, J.; Schweika, W.

2017-01-01

Roč. 12, JAN (2017), č. článku P01019. ISSN 1748-0221 R&D Projects: GA MŠk LM2015048 Institutional support: RVO:61389005 Keywords : instrumentation for neutron sources * neutron diffraction detectors * neutron detectors (cold, thermal, fast neutrons) Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.220, year: 2016

The Super-Kamiokande detector

International Nuclear Information System (INIS)

Fukuda, S.; Fukuda, Y.; Hayakawa, T.; Ichihara, E.; Ishitsuka, M.; Itow, Y.; Kajita, T.; Kameda, J.; Kaneyuki, K.; Kasuga, S.; Kobayashi, K.; Kobayashi, Y.; Koshio, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakayama, S.; Namba, T.; Obayashi, Y.; Okada, A.; Oketa, M.; Okumura, K.; Oyabu, T.; Sakurai, N.; Shiozawa, M.; Suzuki, Y.; Takeuchi, Y.; Toshito, T.; Totsuka, Y.; Yamada, S.; Desai, S.; Earl, M.; Hong, J.T.; Kearns, E.; Masuzawa, M.; Messier, M.D.; Stone, J.L.; Sulak, L.R.; Walter, C.W.; Wang, W.; Scholberg, K.; Barszczak, T.; Casper, D.; Liu, D.W.; Gajewski, W.; Halverson, P.G.; Hsu, J.; Kropp, W.R.; Mine, S.; Price, L.R.; Reines, F.; Smy, M.; Sobel, H.W.; Vagins, M.R.; Ganezer, K.S.; Keig, W.E.; Ellsworth, R.W.; Tasaka, S.; Flanagan, J.W.; Kibayashi, A.; Learned, J.G.; Matsuno, S.; Stenger, V.J.; Hayato, Y.; Ishii, T.; Ichikawa, A.; Kanzaki, J.; Kobayashi, T.; Maruyama, T.; Nakamura, K.; Oyama, Y.; Sakai, A.; Sakuda, M.; Sasaki, O.; Echigo, S.; Iwashita, T.; Kohama, M.; Suzuki, A.T.; Hasegawa, M.; Inagaki, T.; Kato, I.; Maesaka, H.; Nakaya, T.; Nishikawa, K.; Yamamoto, S.; Haines, T.J.; Kim, B.K.; Sanford, R.; Svoboda, R.; Blaufuss, E.; Chen, M.L.; Conner, Z.; Goodman, J.A.; Guillian, E.; Sullivan, G.W.; Turcan, D.; Habig, A.; Ackerman, M.; Goebel, F.; Hill, J.; Jung, C.K.; Kato, T.; Kerr, D.; Malek, M.; Martens, K.; Mauger, C.; McGrew, C.; Sharkey, E.; Viren, B.; Yanagisawa, C.; Doki, W.; Inaba, S.; Ito, K.; Kirisawa, M.; Kitaguchi, M.; Mitsuda, C.; Miyano, K.; Saji, C.; Takahata, M.; Takahashi, M.; Higuchi, K.; Kajiyama, Y.; Kusano, A.; Nagashima, Y.; Nitta, K.; Takita, M.; Yamaguchi, T.; Yoshida, M.; Kim, H.I.; Kim, S.B.; Yoo, J.; Okazawa, H.; Etoh, M.; Fujita, K.; Gando, Y.; Hasegawa, A.; Hasegawa, T.; Hatakeyama, S.; Inoue, K.; Ishihara, K.; Iwamoto, T.; Koga, M.; Nishiyama, I.; Ogawa, H.; Shirai, J.; Suzuki, A.; Takayama, T.; Tsushima, F.; Koshiba, M.; Ichikawa, Y.; Hashimoto, T.; Hatakeyama, Y.; Koike, M.; Horiuchi, T.; Nemoto, M.; Nishijima, K.; Takeda, H.; Fujiyasu, H.; Futagami, T.; Ishino, H.; Kanaya, Y.; Morii, M.; Nishihama, H.; Nishimura, H.; Suzuki, T.; Watanabe, Y.; Kielczewska, D.; Golebiewska, U.; Berns, H.G.; Boyd, S.B.; Doyle, R.A.; George, J.S.; Stachyra, A.L.; Wai, L.L.; Wilkes, R.J.; Young, K.K.; Kobayashi, H.

2003-01-01

Super-Kamiokande is the world's largest water Cherenkov detector, with net mass 50,000 tons. During the period April, 1996 to July, 2001, Super-Kamiokande I collected 1678 live-days of data, observing neutrinos from the Sun, Earth's atmosphere, and the K2K long-baseline neutrino beam with high efficiency. These data provided crucial information for our current understanding of neutrino oscillations, as well as setting stringent limits on nucleon decay. In this paper, we describe the detector in detail, including its site, configuration, data acquisition equipment, online and offline software, and calibration systems which were used during Super-Kamiokande I

Detectors for rare events

International Nuclear Information System (INIS)

Charpak, G.

1984-01-01

This chapter discusses the possibility of combining the advantages of photographic data retrieval with the flexibility of operation of conventional gaseous or liquid detectors operated with electronic data retrieval. Possible applications of the proposed detectors to such problems as nucleon decay, neutrinoelectron interaction, and the search for magnetic monopoles are examined. Topics considered include the photography of ionization patterns, the photography of ionization tracks with the multistep avalanche chambers, and exploiting the stimulated scintillation light. Two processes which give rise to the emission of light when ionizing electrons interact in gases under the influence of an electric field are described

Measurements for the energy calibration of the TANSY neutron detectors

International Nuclear Information System (INIS)

Drozdowicz, K.; Hoek, M.; Aronsson, D.

1990-05-01

The report describes measurements performed for the energy calibration of the TANSY neutron detectors (two arrays of 16 detectors each one). The calibration procedure determines four calibration parameters for each detector. Results of the calibration measurements are given and test measurements are presented. A relation of the neutron detector calibration parameters to producer's data for the photomulipliers is analysed. Also the tests necessary during normal operation of the TANSY neutron spectrometer are elaborated (passive and active tests). A method how to quickly get the calibration parameters for a spare detector in an array of the neutron detectors is included

The Cosmic Ray Tracking (CRT) detector system

International Nuclear Information System (INIS)

Bernloehr, K.; Gamp, S.; Hermann, G.; Hofmann, W.; Kihm, T.; Knoeppler, J.; Leffers, G.; Matheis, V.; Panter, M.; Trunk, U.; Ulrich, M.; Wolf, T.; Zink, R.; Heintze, J.

1996-01-01

The Cosmic Ray Tracking (CRT) project represents a study on the use of tracking detectors of the time projection chamber type to detect secondary cosmic ray particles in extensive air showers. In reconstructing the arrival direction of the primary cosmic ray particles, the CRT detectors take advantage of the angular correlation of secondary particles with the cosmic rays leading to these air showers. In this paper, the detector hardware including the custom-designed electronics system is described in detail. A CRT detector module provides an active area of 2.5 m 2 and allows to measure track directions with a precision of 0.4 circle . It consists of two circular drift chambers of 1.8 m diameter with six sense wires each, and a 10 cm thick iron plate between the two chambers. Each detector has a local electronics box with a readout, trigger, and monitoring system. The detectors can distinguish penetrating muons from other types of charged secondaries. A large detector array could be used to search for γ-ray point sources at energies above several TeV and for studies of the cosmic-ray composition. Ten detectors are in operation at the site of the HEGRA air shower array. (orig.)

A particle finite element method for machining simulations

Science.gov (United States)

Sabel, Matthias; Sator, Christian; Müller, Ralf

2014-07-01

The particle finite element method (PFEM) appears to be a convenient technique for machining simulations, since the geometry and topology of the problem can undergo severe changes. In this work, a short outline of the PFEM-algorithm is given, which is followed by a detailed description of the involved operations. The -shape method, which is used to track the topology, is explained and tested by a simple example. Also the kinematics and a suitable finite element formulation are introduced. To validate the method simple settings without topological changes are considered and compared to the standard finite element method for large deformations. To examine the performance of the method, when dealing with separating material, a tensile loading is applied to a notched plate. This investigation includes a numerical analysis of the different meshing parameters, and the numerical convergence is studied. With regard to the cutting simulation it is found that only a sufficiently large number of particles (and thus a rather fine finite element discretisation) leads to converged results of process parameters, such as the cutting force.

2011 ATLAS Detector Performance - ID and Forward detectors

CERN Document Server

Davies‎, E; The ATLAS collaboration; Abdel Khalek, S

2012-01-01

This poster describes the performance of 2 parts of ATLAS: - The Inner Detector which consists of 3 subdetectors: the Pixel detector, the SemiConductor Tracker (or SCT) and the Transition Radiation Tracker (or TRT). Here, we report on Pixel detector and SCT performance over 2011. - ALFA detector which will determine the absolute luminosity of the CERN LHC at the ATLAS Interaction Point (IP), and the total proton-proton cross section, by tracking elastically scattered protons at very small angles in the limit of the Coulomb Nuclear interference region.

Electromagnetic disturbance neutralizing radiation detector

International Nuclear Information System (INIS)

Gripentog, W.G.

1975-01-01

A radiation detector of the Neher-White type is described which automatically neutralizes induced negative charges on the electrometer tube control grid which shut off the electrometer tube. The detector includes means for establishing a voltage of one polarity in response to plate current and voltage of opposite polarity in response to an absence of plate current and means for connecting the control grid to a reference potential for draining the negative charge in response to the voltage of opposite polarity. (author)

A New Principle in Physics: the Principle 'Finiteness', and Some Consequences

International Nuclear Information System (INIS)

Sternlieb, Abraham

2010-01-01

In this paper I propose a new principle in physics: the principle of 'finiteness'. It stems from the definition of physics as a science that deals (among other things) with measurable dimensional physical quantities. Since measurement results, including their errors, are always finite, the principle of finiteness postulates that the mathematical formulation of 'legitimate' laws of physics should prevent exactly zero or infinite solutions. Some consequences of the principle of finiteness are discussed, in general, and then more specifically in the fields of special relativity, quantum mechanics, and quantum gravity. The consequences are derived independently of any other theory or principle in physics. I propose 'finiteness' as a postulate (like the constancy of the speed of light in vacuum, 'c'), as opposed to a notion whose validity has to be corroborated by, or derived theoretically or experimentally from other facts, theories, or principles.

Infrared detectors

CERN Document Server

Rogalski, Antonio

2010-01-01

This second edition is fully revised and reorganized, with new chapters concerning third generation and quantum dot detectors, THz detectors, cantilever and antenna coupled detectors, and information on radiometry and IR optics materials. Part IV concerning focal plane arrays is significantly expanded. This book, resembling an encyclopedia of IR detectors, is well illustrated and contains many original references … a really comprehensive book.-F. Sizov, Institute of Semiconductor Physics, National Academy of Sciences, Kiev, Ukraine

Ionization smoke detector and alarm system

International Nuclear Information System (INIS)

1974-01-01

An ionization smoke detector particularly suited to residential use is disclosed. The detector is battery-operated and is connected with a non-latching, pulsating alarm circuit. The detector has a sensing chamber formed by a perforated metallic shell and an electrode within which an insulated radiation source is centrally positioned to generate an ionization current for detecting smoke or other similar aerosols. The alarm circuit provides a pulsating alarm signal when smoke levels above a pre-determined value are sensed. The alarm circuit also includes a low voltage detection circuit for sounding the alarm when the end of useful battery life is approaching. (Auth.)

On finite quantum field theories

International Nuclear Information System (INIS)

Rajpoot, S.; Taylor, J.G.

1984-01-01

The properties that make massless versions of N = 4 super Yang-Mills theory and a class of N = 2 supersymmetric theories finite are: (I) a universal coupling for the gauge and matter interactions, (II) anomaly-free representations to which the bosonic and fermionic matter belong, and (III) no charge renormalisation, i.e. β(g) = 0. It was conjectured that field theories constructed out of N = 1 matter multiplets are also finite if they too share the above properties. Explicit calculations have verified these theories to be finite up to two loops. The implications of the finiteness conditions for N = 1 finite field theories with SU(M) gauge symmetry are discussed. (orig.)

Simulation of drift dynamics of arbitrary carrier distributions in complex semiconductor detectors

CERN Document Server

De Castro Manzano, Pablo

2014-01-01

An extensible open-source C++ software for the simulation of elec- trons and holes drift in semiconductor detectors of complex geometries has been developed in order to understand transient currents and charge collection efficiencies of arbitrary charge distributions. The simulation is based on Ramo’s theorem formalism to obtain induced currents in the electrodes. Efficient open source C++ numerical libraries are used to ob- tain the electric and weighting field using finite-element methods and to simulate the carrier transport. A graphical user interface is also provided. The tool has already been proved useful to model laser induced transient currents

Finite size scaling theory

International Nuclear Information System (INIS)

Rittenberg, V.

1983-01-01

Fischer's finite-size scaling describes the cross over from the singular behaviour of thermodynamic quantities at the critical point to the analytic behaviour of the finite system. Recent extensions of the method--transfer matrix technique, and the Hamiltonian formalism--are discussed in this paper. The method is presented, with equations deriving scaling function, critical temperature, and exponent v. As an application of the method, a 3-states Hamiltonian with Z 3 global symmetry is studied. Diagonalization of the Hamiltonian for finite chains allows one to estimate the critical exponents, and also to discover new phase transitions at lower temperatures. The critical points lambda, and indices v estimated for finite-scaling are given

3D IC for future HEP detectors

International Nuclear Information System (INIS)

Thom, J; Badman, R; Lipton, R; Johnson, M; Spiegel, L; Deptuch, G; Ye, Z; Heintz, U; Narain, M; Triphati, M; Kenney, C; Parker, S; Siddons, D P

2014-01-01

Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. We describe ongoing R and D efforts to demonstrate functionality of components of such detectors. This includes the study of integrated 3D electronics with active edge sensors to produce ''active tiles'' which can be tested and assembled into arrays of arbitrary size with high yield

The forward Detectors of the ATLAS experiment

CERN Document Server

Vittori, Camilla; The ATLAS collaboration

2017-01-01

In this poster, a review of the ATLAS forward detectors operating in the 2015-2016 data taking is given. This includes a description of LUCID, the preferred ATLAS luminosity provider; of the ALFA detector, aimed to measure elastically scattered protons at small angle for the total proton-proton cross section measurement; of the ATLAS Forward Proton project AFP, which was partially installed and took the first data in 2015, and of the Zero Degree Calorimeter ZDC built for the ATLAS Heavy Ions physics program. The near future plans for these detectors will also be addressed.

Modeling and design of X-rays bidimensional detectors

International Nuclear Information System (INIS)

Quisbert, Elmer Paz Alcon

2000-03-01

In this work has been developed the scintillating fiber optic and semiconductor devices based 2-D detector design, modeling and performance evaluation using Monte Carlo methods, for high X-ray energy range (10-140 kV) radiography and tomography applications. These processes allowed us, also, the imaging system parameters and components optimization and appropriate detector design. The model estimated the detectors performance parameters (DQE, MTF and SNR), and radiation risk (in terms of mean absorbed dose in the patient) and to show up how the sequence of physical processes in X-ray detection influence the performance of this imaging PFOC detectors. In this way, the modeling of the detector includes the statistics of the spatial distribution of absorbed X-rays and of X-ray to light conversion, its transmission, and the light quanta conversion into electrons. Also contributions to noise from the detection system chain is included, mainly the CCD detector ambient noise. Performance prediction, based on calculation taken from simulations, illustrates how such detectors meet the exacting requirements of some medical and industrial applications. Also, it is envisaged that our modeling procedure of the imaging system will be suitable not only for investigating how the system components should be best designed but for CT and RD system performance prediction. The powerful techniques would enable us to give advice for future development, in this field, in search of more dose-efficient imaging systems. (author)

Computer modelling of position-sensitive scintillator detectors

International Nuclear Information System (INIS)

Schelten, J.; Kurz, R.; Kernforschungsanlage Juelich G.m.b.H.

1983-01-01

The essential properties of a two-dimensional PSD consisting of 7 x 7 circular PMs of diameter D = 68 mm, optically coupled to a glass block disperser of thickness H, and of a thin glass scintillator which is optically decoupled from the disperser are analyzed by computer-simulation of the detector geometry which determines the light distribution on rows and columns of PMs for a neutron capture event and the electronic signal handling which leads to the response function Q(x,y). The computer simulations were performed in order to investigate geometrical variations, such as PMs with a square photo-cathode, a hexagonal arrangement, the effect of the disperser thickness and of conical condensers in front of the PMs and edge-effects due to the finite size of the disperser. The linearity of the detector can be optimised by adjusting three smoothing parameters S, S' and S''. These parameters can be introduced if the signal processing, which determines a neutron event, is based on a course selection of three PM columns and three rows followed by a weighted pulse height division for a final determination of the x and y coordinates. This paper briefly describes the simulations and presents the calculated results which refer closely to the two-dimensional PSD which is being built in the Laboratory. (author)

Silicon Drift Detectors - A Novel Technology for Vertex Detectors

Science.gov (United States)

Lynn, D.

1996-10-01

Silicon Drift Detectors (SDD) are novel position sensing silicon detectors which operate in a manner analogous to gas drift detectors. Single SDD's were shown in the CERN NA45 experiment to permit excellent spatial resolution (pseudo-rapidity. Over the last three years we undertook a concentrated R+D effort to optimize the performance of the detector by minimizing the inactive area, the operating voltage and the data volume. We will present test results from several wafer prototypes. The charge produced by the passage of ionizing particles through the bulk of the detectors is collected on segmented anodes, with a pitch of 250 μm, on the far edges of the detector. The anodes are wire-bonded to a thick film multi-chip module which contains preamplifier/shaper chips and CMOS based switched capacitor arrays used as an analog memory pipeline. The ADC is located off-detector. The complete readout chain from the wafer to the DAQ will be presented. Finally we will show physics performance simulations based on the resolution achieved by the SVT prototypes.

CZT drift strip detectors for high energy astrophysics

DEFF Research Database (Denmark)

Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Caroli, E.

2010-01-01

Requirements for X- and gamma ray detectors for future High Energy Astrophysics missions include high detection efficiency and good energy resolution as well as fine position sensitivity even in three dimensions.We report on experimental investigations on the CZT drift detector developed DTU Space...

Self-powered flux detectors

International Nuclear Information System (INIS)

Shields, R.B.

1983-02-01

This bibliography attempts to cover the published literature on the class of radiation detectors most often referred to as 'self-powered'. For this purpose, self-powered detectors are defined as those that have two or more conducting electrodes separated by solid insulation and that generate a signal current without an external power source. Primary sensitivity is unrestricted, but it is usually to neutrons or gamma-rays. The main application is in the core of a nuclear reactor. All relevant facets of the subject are covered including: theory, experiment, development, design, manufacture, instrumentation and application. In addition to the usual reference information, various other designations are included where available, such as CONF-and abstract serial numbers. Where possible, a summary of the content is given with emphasis on specific results and conclusions. Indexing is by author and subject

Collisions of neutrons and of gamma rays in Bi4Ge3O12 (BGO) and NaI(Tl) scintillation detectors

International Nuclear Information System (INIS)

Kushneriuk, S.A.; Lone, M.A.; Hausser, O.; Wong, P.Y.

1983-06-01

The role of collision/escape probabilities in establishing the prompt response of bismuth germanate and NaI(Tl) scintillators is investigated. A possible approximation to the collision probability is discussed. Exact expressions for the probability of escape of radiation from finite, right circular cylindrical and rectangular parallelepiped-shaped detectors are derived from an exponential-like spatial distribution of the source in the detector medium and a parametrized angular distribution of emission of the source. Fairly extensive tables of collision probabilities calculated for these bodies are given. For purposes of comparison some results obtained previously in a Monte Carlo calculation are also presented and discussed

Interference coupling mechanisms in Silicon Strip Detectors - CMS tracker "wings" A learned lesson for SLHC

CERN Document Server

Arteche, F; Rivetta, C

2009-01-01

The identification of coupling mechanisms between noise sources and sensitive areas of the front-end electronics (FEE) in the previous CMS tracker sub-system is critical to optimize the design and integration of integrated circuits, sensors and power distribution circuitry for the proposed SLHC Silicon Strip Tracker systems. This paper presents a validated model of the noise sensitivity observed in the Silicon Strip Detector-FEE of the CMS tracker that allows quantifying both the impact of the noise coupling mechanisms and the system immunity against electromagnetic interferences. This model has been validated based on simulations using finite element models and immunity tests conducted on prototypes of the Silicon Tracker End-Caps (TEC) and Outer Barrel (TOB) systems. The results of these studies show important recommendations and criteria to be applied in the design of future detectors to increase the immunity against electromagnetic noise.

Small area detectors at the European XFEL

Science.gov (United States)

Turcato, M.; Gessler, P.; Hauf, S.; Kuster, M.; Meyer, M.; Nordgren, J.; Sztuk-Dambietz, J.; Youngman, C.

2014-05-01

The detectors to be used at the European XFEL have to deal with the unique time structure of the machine, delivering up to 2700 pulses, with a repetition rate of 4.5 MHz, ten times per second, the very high photon flux and the need to combine single-photon sensitivity and a large dynamic range. This represents a challenge not only for the large-area 2D imaging detectors but also for the smaller-area detectors and makes the use of standard commercial devices impossible. Dedicated solutions are therefore envisaged for small imaging- or strip-detectors. In this contribution the focus is put on two particular small-area detector solutions which are planned to be used at the European XFEL, a strip detector for hard X-rays (with energy 3 < E < 25 keV) and an imaging detector for soft X-rays (0.25 < E < 3 keV). Hard X-rays photon-beam diagnostics as well as hard X-ray absorption and emission spectroscopy at the European XFEL make use of strip detectors as detectors for beam spectrometers or as energy-dispersive detectors in combination with an energy-dispersive element. The European XFEL is establishing cooperation with the Paul Scherrer Institute in Villigen to develop a new version of the Gotthard detector best suited to the European XFEL needs. The use case and the required detector specifications are illustrated. Starting from the present detector version, the modifications planned to adapt it to the European XFEL running conditions are described. These include the capability of running at an increased rate and to provide a veto signal to the large 2D imaging detectors, in order to be able to remove non-interesting images already at early stages of the DAQ system. In another particular application, resonant inelastic X-ray scattering, a Micro-Channel Plate detector matched to a delay-line readout is foreseen to be used. In this case the European XFEL is aiming for a highly customized solution provided by the German company Surface Concept. The use case is described

Recent upgrades and performance of the CACTUS detector array

International Nuclear Information System (INIS)

Schiller, A.; Bergholt, L.; Guttormsen, M.

1998-03-01

The SCANDITRONIX MC-35 cyclotron laboratory, including the Oslo Cyclotron, has been in operation since 1980. The main auxiliary equipment consists of the multi-detector system CACTUS. During the last years, new, high efficiency Ge(HP) detectors were purchased and integrated in the CACTUS detector array. In this connection, the electronical setup was revised and altered. Several drawbacks of the old setup could be pointed out and eliminated. A test of the performance of all detector array elements was made with high accuracy. 27 refs

$\\delta$-Expansion at Finite Temperature

OpenAIRE

Ramos, Rudnei O.

1996-01-01

We apply the $\\delta$-expansion perturbation scheme to the $\\lambda \\phi^{4}$ self-interacting scalar field theory in 3+1 D at finite temperature. In the $\\delta$-expansion the interaction term is written as $\\lambda (\\phi^{2})^{ 1 + \\delta}$ and $\\delta$ is considered as the perturbation parameter. We compute within this perturbative approach the renormalized mass at finite temperature at a finite order in $\\delta$. The results are compared with the usual loop-expansion at finite temperature.

Life Finder Detectors: An Overview of Detector Technologies for Detecting Life on Other Worlds

Science.gov (United States)

Rauscher, Bernard J.; Domagal-Goldman, Shawn; Greenhouse, Matthew A.; Hsieh, Wen-Ting; McElwain, Michael W.; Moseley, Samuel H.; Noroozian, Omid; Norton, Tim; Kutyrev, Alexander; Rinehart, Stephen; stock, Joseph

2015-01-01

Future large space telescopes will seek evidence for life on other worlds by searching for spectroscopic biosignatures. Atmospheric biosignature gases include oxygen, ozone, water vapor, and methane. Non-biological gases, including carbon monoxide and carbon dioxide, are important for discriminating false positives. All of these gases imprint spectroscopic features in the UV through mid-IR that are potentially detectable using future space based coronagraphs or star shades for starlight suppression.Direct spectroscopic biosignature detection requires sensors capable of robustly measuring photon arrival rates on the order of 10 per resolution element per hour. Photon counting is required for some wavefront sensing and control approaches to achieve the requisite high contrast ratios. We review life finder detector technologies that either exist today, or are under development, that have the potential to meet these challenging requirements. We specifically highlight areas where more work or development is needed.Life finder detectors will be invaluable for a wide variety of other major science programs. Because of its cross cutting nature; UV, optical, and infrared (UVOIR) detector development features prominently in the 2010 National Research Council Decadal Survey, 'New Worlds, New Horizons in Astronomy and Astrophysics', and the NASA Cosmic Origins Program Technology Roadmap.

Finite spatial volume approach to finite temperature field theory

International Nuclear Information System (INIS)

Weiss, Nathan

1981-01-01

A relativistic quantum field theory at finite temperature T=β -1 is equivalent to the same field theory at zero temperature but with one spatial dimension of finite length β. This equivalence is discussed for scalars, for fermions, and for gauge theories. The relationship is checked for free field theory. The translation of correlation functions between the two formulations is described with special emphasis on the nonlocal order parameters of gauge theories. Possible applications are mentioned. (auth)

Material model for non-linear finite element analyses of large concrete structures

NARCIS (Netherlands)

Engen, Morten; Hendriks, M.A.N.; Øverli, Jan Arve; Åldstedt, Erik; Beushausen, H.

2016-01-01

A fully triaxial material model for concrete was implemented in a commercial finite element code. The only required input parameter was the cylinder compressive strength. The material model was suitable for non-linear finite element analyses of large concrete structures. The importance of including

Synthesis of hydrocode and finite element technology for large deformation Lagrangian computation

International Nuclear Information System (INIS)

Goudreau, G.L.; Hallquist, J.O.

1979-08-01

Large deformation engineering analysis at Lawrence Livermore Laboratory has benefited from a synthesis of computational technology from the finite difference hydrocodes of the scientific weapons community and the structural finite element methodology of engineering. Two- and three-dimensional explicit and implicit Lagrangian continuum codes have been developed exploiting the strengths of each. The explicit methodology primarily exploits the primitive constant stress (or one point integration) brick element. Similarity and differences with the integral finite difference method are discussed. Choice of stress and finite strain measures, and selection of hour glass viscosity are also considered. The implicit codes also employ a Cauchy formulation, with Newton iteration and a symmetric tangent matrix. A library of finite strain material routines includes hypoelastic/plastic, hyperelastic, viscoelastic, as well as hydrodynamic behavior. Arbitrary finite element topology and a general slide-line treatment significantly extends Lagrangian hydrocode application. Computational experience spans weapons and non-weapons applications

COMMISSIONING AND DETECTOR PERFORMANCE GROUPS (DPG)

CERN Multimedia

Darin Acosta

The pace of activity is high for the Detector Performance Groups now that the CMS experiment is complete for 2008 and LHC beams are imminent. This includes refinement of the data quality monitoring tools (including prompt offline analyses), triggers, reconstruction code, and calibration and alignment conditions. Notable since the last CMS Week has been the inclusion of the strip tracker into the global running in July and the inclusion of the pixel systems and ECAL endcaps in August. The following describes the highlights from each group. During the CRUZET3 global run in July (the third installment of the Cosmic Run at Zero Tesla exercise) the Silicon Strip tracker recorded data with all barrel detectors and one side of the end-cap wheels. The week-long data-taking period delivered about 300k tracks good for detector alignment and was an extremely valuable experience to test the reconstruction, calibration and alignment workflows in their final configuration. Events with tracks were selected in real-time at ...

The vertex detector for the Lepton/Photon collaboration

Energy Technology Data Exchange (ETDEWEB)

Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E. [Los Alamos National Lab., NM (United States)

1991-12-31

The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.

The vertex detector for the Lepton/Photon Collaboration

International Nuclear Information System (INIS)

Sullivan, J.P.; Boissevain, J.G.; Fox, D.; van Hecke, H.; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E.

1991-01-01

The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two concentric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity η distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed

Long-distance transmission of light in a scintillator-based radiation detector

Science.gov (United States)

Dowell, Jonathan L.; Talbott, Dale V.; Hehlen, Markus P.

2017-07-11

Scintillator-based radiation detectors capable of transmitting light indicating the presence of radiation for long distances are disclosed herein. A radiation detector can include a scintillator layer and a light-guide layer. The scintillator layer is configured to produce light upon receiving incident radiation. The light-guide layer is configured to receive light produced by the scintillator layer and either propagate the received light through the radiation detector or absorb the received light and emit light, through fluorescence, that is propagated through the radiation detector. A radiation detector can also include an outer layer partially surrounding the scintillator layer and light-guide layer. The index of refraction of the light-guide layer can be greater than the index of refraction of adjacent layers.

Spiral silicon drift detectors

International Nuclear Information System (INIS)

Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

1988-01-01

An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

NaI Detector Network at Aragats

International Nuclear Information System (INIS)

Avakyan, Karen; Arakelyan, Karen; Chilingarian, Ashot; Daryan, Ara; Kozliner, Lev; Mailyan, Bagrat; Hovsepyan, Gagik; Pokhsraryan, David; Sargsyan, David

2013-01-01

The Aragats Space Environmental Center (ASEC) provides monitoring of different species of secondary cosmic rays and consists of two high altitude research stations on Mt. Aragats in Armenia. Along with solar modulation effects, ASEC detectors register several coherent enhancements associated with thunderstorm activity. The experimental techniques used allowed for the first time to simultaneously measure fluxes of the electrons, muons, gamma rays, and neutrons correlated with thunderstorm activity. Ground-based observations by a complex of surface particle detectors, measuring in systematically and repeatable fashion, gamma quanta, electrons, muons and neutrons from atmospheric sources are necessary for proving the theory of particle acceleration and multiplication during thunderstorms. Energy spectra and correlations between fluxes of different particles, measured on Earth's surface address the important issues of research of the solar modulation effects and the atmospheric high-energy phenomena. In May 26 2011, launched 5 NaI(Tl) (thallium-doped sodium iodide) scintillation detectors and 1 plastic one in the new ASEC laboratory on Aragats to detect low energy gamma rays from the thunderclouds and short particle bursts. Including NaI(Tl) detectors in ASEC detectors system is of great importance for investigation thunderstorm phenomena because NaI(Tl) detectors have high efficiency of gamma ray detecting in comparison with plastic ones.

Radiation detectors laboratory

International Nuclear Information System (INIS)

Ramirez J, F.J.

1996-01-01

The National Institute for Nuclear Research has established a Radiation detector laboratory that has the possibility of providing to the consultants on the handling and applications of the nuclear radiation detectors. It has special equipment to repair the radiation detectors used in spectroscopy as the hyper pure Germanium for gamma radiation and the Lithium-silica for X-rays. There are different facilities in the laboratory that can become useful for other institutions that use radiation detectors. This laboratory was created to satisfy consultant services, training and repairing of the radiation detectors both in national and regional levels for Latin America. The laboratory has the following sections: Nuclear Electronic Instrumentation; where there are all kind of instruments for the measurement and characterization of detectors like multichannel analyzers of pulse height, personal computers, amplifiers and nuclear pulse preamplifiers, nuclear pulses generator, aleatories, computer programs for radiation spectra analysis, etc. High vacuum; there is a vacuum escape measurer, two high vacuum pumps to restore the vacuum of detectors, so the corresponding measurers and the necessary tools. Detectors cleaning; there is an anaerobic chamber for the detectors handling at inert atmosphere, a smoke extraction bell for cleaning with the detector solvents. Cryogenic; there are vessels and tools for handling liquid nitrogen which is used for cooling the detectors when they required it. (Author)

Comparison of natural and synthetic diamond X-ray detectors.

Science.gov (United States)

Lansley, S P; Betzel, G T; Metcalfe, P; Reinisch, L; Meyer, J

2010-12-01

Diamond detectors are particularly well suited for dosimetry applications in radiotherapy for reasons including near-tissue equivalence and high-spatial resolution resulting from small sensitive volumes. However, these detectors have not become commonplace due to high cost and poor availability arising from the need for high-quality diamond. We have fabricated relatively cheap detectors from commercially-available synthetic diamond fabricated using chemical vapour deposition. Here, we present a comparison of one of these detectors with the only commercially-available diamond-based detector (which uses a natural diamond crystal). Parameters such as the energy dependence and linearity of charge with dose were investigated at orthovoltage energies (50-250 kV), and dose-rate dependence of charge at linear accelerator energy (6 MV). The energy dependence of a synthetic diamond detector was similar to that of the natural diamond detector, albeit with slightly less variation across the energy range. Both detectors displayed a linear response with dose (at 100 kV) over the limited dose range used. The sensitivity of the synthetic diamond detector was 302 nC/Gy, compared to 294 nC/Gy measured for the natural diamond detector; however, this was obtained with a bias of 246.50 V compared to a bias of 61.75 V used for the natural diamond detector. The natural diamond detector exhibited a greater dependency on dose-rate than the synthetic diamond detector. Overall, the synthetic diamond detector performed well in comparison to the natural diamond detector.

The ATLAS Detector Safety System

CERN Multimedia

Helfried Burckhart; Kathy Pommes; Heidi Sandaker

The ATLAS Detector Safety System (DSS) has the mandate to put the detector in a safe state in case an abnormal situation arises which could be potentially dangerous for the detector. It covers the CERN alarm severity levels 1 and 2, which address serious risks for the equipment. The highest level 3, which also includes danger for persons, is the responsibility of the CERN-wide system CSAM, which always triggers an intervention by the CERN fire brigade. DSS works independently from and hence complements the Detector Control System, which is the tool to operate the experiment. The DSS is organized in a Front- End (FE), which fulfills autonomously the safety functions and a Back-End (BE) for interaction and configuration. The overall layout is shown in the picture below. ATLAS DSS configuration The FE implementation is based on a redundant Programmable Logical Crate (PLC) system which is used also in industry for such safety applications. Each of the two PLCs alone, one located underground and one at the s...

The status of detectors at the SSC

International Nuclear Information System (INIS)

Stefanski, R.

1990-09-01

The announcement of the location of the SSC at the site near Waxahachie, Texas was made in January, 1989. Since then a great many important steps have been taken toward the start of the new Laboratory. Some 900 people have been brought to the site as the starting nucleus of the staff that will ultimate number about 2200. A design baseline has been completed that includes a conceptual design for the accelerator, and the detectors. Also, the process has begun to determine the configuration of detectors that will be built for the SSC. This process has several steps, and now the first of these has been taken: The detector collaborations have submitted the Expression of Interest to the Laboratory. These were reviewed by Laboratory management and the Physics Advisory Committee in July, 1990 and recommendations were made to the collaborations. Decisions were deferred for all of the detectors. But perhaps the most significant recommendation was the request to reduce the size and cost of the general purpose detectors. The detector collaborations are now reviewing their initial designs to prepare for the Letters of Intent, the next step in the detector planning process. This is clearly a difficult and crucial step in that the redesign of the detectors must be done with minimal reduction in detector quality. It is an interesting time in the development of the new laboratory, and a crucial time for the ultimate physics that will be done at the SSC

The 150 ns detector project: Prototype preamplifier results

Science.gov (United States)

Warburton, W. K.; Russell, S. R.; Kleinfelder, Stuart A.

1994-08-01

The long-term goal of the 150 ns detector project is to develop a pixel area detector capable of 6 MHz frame rates (150 ns/frame). Our milestones toward this goal are: a single pixel, 1×256 1D and 8×8 2D detectors, 256×256 2D detectors and, finally, 1024 × 1024 2D detectors. The design strategy is to supply a complete electronics chain (resetting preamp, selectable gain amplifier, analog-to-digital converter (ADC), and memory) for each pixel. In the final detectors these will all be custom integrated circuits. The front-end preamplifiers are integrated first, since their design and performance are the most unusual and also critical to the project's success. Similarly, our early work is concentrated on devising and perfecting detector structures. In this paper we demonstrate the performance of prototypes of our integrated preamplifiers. While the final design will have 64 preamps to a chip, including a switchable gain stage, the prototypes were integrated 8 channels to a "Tiny Chip" and tested in 4 configurations (feedback capacitor Cf equal 2.5 or 4.0 pF, output directly or through a source follower). These devices have been tested thoroughly for reset settling times, gain, linearity, and electronic noise. They generally work as designed, being fast enough to easily integrate detector charge, settle, and reset in 150 ns. Gain and linearity appear to be acceptable. Current values of electronic noise, in double-sampling mode, are about twice the design goal of {2}/{3} of a single photon at 6 keV. We expect this figure to improve with the addition of the onboard amplifier stage and improved packaging. Our next test chip will include these improvements and allow testing with our first detector samples, which will be 1×256 (50 μm wide pixels) and 8×8 (1 mm 2 pixels) element detector on 1 mm thick silicon.

Radiation detector system having heat pipe based cooling

Science.gov (United States)

Iwanczyk, Jan S.; Saveliev, Valeri D.; Barkan, Shaul

2006-10-31

A radiation detector system having a heat pipe based cooling. The radiation detector system includes a radiation detector thermally coupled to a thermo electric cooler (TEC). The TEC cools down the radiation detector, whereby heat is generated by the TEC. A heat removal device dissipates the heat generated by the TEC to surrounding environment. A heat pipe has a first end thermally coupled to the TEC to receive the heat generated by the TEC, and a second end thermally coupled to the heat removal device. The heat pipe transfers the heat generated by the TEC from the first end to the second end to be removed by the heat removal device.

Prototype Performance of Novel Muon Telescope Detector at STAR

International Nuclear Information System (INIS)

Ruan, L.

2008-01-01

Research on a large-area, cost-effective Muon Telescope Detector (MTD) has been carried out for RHIC and for next generation detectors at future QCD Lab. We utilize state-of-the-art multi-gap resistive plate chambers with large modules and long readout strips in detector design. The results from cosmic ray and beam test will be presented to address intrinsic timing and spatial resolution for a Long-MRPC. The prototype performance of a novel muon telescope detector at STAR will be reported, including muon identification capability, timing and spatial resolution

Prototype performance of novel muon telescope detector at STAR

International Nuclear Information System (INIS)

Ruan, L.; Ames, V.

2011-01-01

Research on a large-area, cost-effective Muon Telescope Detector has been carried out for RHIC and for next generation detectors at future QCD Lab. We utilize state-of-the-art multi-gap resistive plate chambers with large modules and long readout strips in detector design. The results from cosmic ray and beam test will be presented to address intrinsic timing and spatial resolution for a Long-MRPC. The prototype performance of a novel muon telescope detector at STAR will be reported, including muon identification capability, timing and spatial resolution. (author)

Global-Local Finite Element Analysis of Bonded Single-Lap Joints

Science.gov (United States)

Kilic, Bahattin; Madenci, Erdogan; Ambur, Damodar R.

2004-01-01

Adhesively bonded lap joints involve dissimilar material junctions and sharp changes in geometry, possibly leading to premature failure. Although the finite element method is well suited to model the bonded lap joints, traditional finite elements are incapable of correctly resolving the stress state at junctions of dissimilar materials because of the unbounded nature of the stresses. In order to facilitate the use of bonded lap joints in future structures, this study presents a finite element technique utilizing a global (special) element coupled with traditional elements. The global element includes the singular behavior at the junction of dissimilar materials with or without traction-free surfaces.

On the growth of rank for subgroups of finitely generated groups

International Nuclear Information System (INIS)

Osin, D V

1999-01-01

In [1] and [2] the functions of rank growth were independently introduced and investigated for subgroups of a finitely generated free group. In the present paper the concept of growth of rank is extended to subgroups of an arbitrary finitely generated group G, and the dependence of the asymptotic behaviour of the above functions on the choice of a finite generating set in G is studied. For a broad class of groups (which includes, in particular, the free polynilpotent groups) estimates for the growth of rank for subgroups are obtained that generalize the wellknown Baumslag-Eidel'kind result on finitely generated normal subgroups. Some problems related to the realization of arbitrary functions as functions of rank growth for subgroups of soluble groups are treated

The finite element analysis program MSC Marc/Mentat a first introduction

CERN Document Server

Öchsner, Andreas

2016-01-01

Based on simple examples, this book offers a short introduction to the general-purpose finite element program MSC Marc, a specialized program for non-linear problems (implicit solver) distributed by the MSC Software Corporation, which is commonly used in academia and industry. Today the documentation of all finite element programs includes a variety of step-by-step examples of differing complexity, and in addition, all software companies offer professional workshops on different topics. As such, rather than competing with these, the book focuses on providing simple examples, often single-element problems, which can easily be related to the theory that is discussed in finite element lectures. This makes it an ideal companion book to classical introductory courses on the finite element method.

Excitations of Bose-Einstein condensates at finite temperatures

International Nuclear Information System (INIS)

Rusch, M.

2000-01-01

Recent experimental observations of collective excitations of Bose condensed atomic vapours have stimulated interest in the microscopic description of the dynamics of a Bose-Einstein condensate confined in an external potential. We present a finite temperature field theory for collective excitations of trapped Bose-Einstein condensates and use a finite-temperature linear response formalism, which goes beyond the simple mean-field approximation of the Gross-Pitaevskii equation. The effect of the non-condensed thermal atoms we include using perturbation theory in a quasiparticle basis. This presents a simple scheme to understand the interaction between condensate and non-condensed atoms and enables us to include the effect the condensate has on collision dynamics. At first we limit our treatment to the case of a spatially homogeneous Bose gas. We include the effect of pair and triplet anomalous averages and thus obtain a gapless theory for the excitations of a weakly interacting system, which we can link to well known results for Landau and Beliaev damping rates. A gapless theory for trapped systems with a static thermal component follows straightforwardly. We then investigate finite temperature excitations of a condensate in a spherically symmetric harmonic trap. We avoid approximations to the density of states and thus emphasise finite size aspects of the problem. We show that excitations couple strongly to a restricted number of modes, giving rise to resonance structure in their frequency spectra. Where possible we derive energy shifts and lifetimes of excitations. For one particular mode, the breathing mode, the effects of the discreteness of the system are sufficiently pronounced that the simple picture of an energy shift and width fails. Experiments in spherical traps have recently become feasible and should be able to test our detailed quantitative predictions. (author)

Detectors and flux instrumentation for future neutrino facilities

CERN Document Server

Abe, T.; Andreopoulos, C.; Ankowski, A.; Badertscher, A.; Battistoni, G.; Blondel, A.; Bouchez, J.; Bross, A.; Bueno, A.; Camilleri, L.; Campagne, Jean-Eric; Cazes, A.; Cervera-Villanueva, A.; De Lellis, G.; Di Capua, F.; Ellis, Malcolm; Ereditato, A.; Esposito, L.S.; Fukushima, C.; Gschwendtner, E.; Gomez-Cadenas, J.J.; Iwasaki, M.; Kaneyuki, K.; Karadzhov, Y.; Kashikhin, V.; Kawai, Y.; Komatsu, M.; Kozlovskaya, E.; Kudenko, Y.; Kusaka, A.; Kyushima, H.; Longhin, A.; Marchionni, A.; Marotta, A.; McGrew, C.; Menary, S.; Meregaglia, A.; Mezzeto, M.; Migliozzi, P.; Mondal, N.K.; Montanari, C.; Nakadaira, T.; Nakamura, M.; Nakumo, H.; Nakayama, H.; Nelson, J.; Nowak, J.; Ogawa, S.; Peltoniemi, J.; Pla-Dalmau, A.; Ragazzi, S.; Rubbia, A.; Sanchez, F.; Sarkamo, J.; Sato, O.; Selvi, M.; Shibuya, H.; Shozawa, M.; Sobczyk, J.; Soler, F.J.P.; Strolin, Paolo Emilio; Suyama, M.; Tanak, M.; Terranova, F.; Tsenov, R.; Uchida, Y.; Weber, A.; Zlobin, A.

2009-01-01

This report summarises the conclusions from the detector group of the International Scoping Study of a future Neutrino Factory and Super-Beam neutrino facility. The baseline detector options for each possible neutrino beam are defined as follows: 1. A very massive (Megaton) water Cherenkov detector is the baseline option for a sub-GeV Beta Beam and Super Beam facility. 2. There are a number of possibilities for either a Beta Beam or Super Beam (SB) medium energy facility between 1-5 GeV. These include a totally active scintillating detector (TASD), a liquid argon TPC or a water Cherenkov detector. 3. A 100 kton magnetized iron neutrino detector (MIND) is the baseline to detect the wrong sign muon final states (golden channel) at a high energy (20-50 GeV) neutrino factory from muon decay. A 10 kton hybrid neutrino magnetic emulsion cloud chamber detector for wrong sign tau detection (silver channel) is a possible complement to MIND, if one needs to resolve degeneracies that appear in the $\\delta$-$\\theta_{13}$...

Mesh-size errors in diffusion-theory calculations using finite-difference and finite-element methods

International Nuclear Information System (INIS)

Baker, A.R.

1982-07-01

A study has been performed of mesh-size errors in diffusion-theory calculations using finite-difference and finite-element methods. As the objective was to illuminate the issues, the study was performed for a 1D slab model of a reactor with one neutron-energy group for which analytical solutions were possible. A computer code SLAB was specially written to perform the finite-difference and finite-element calculations and also to obtain the analytical solutions. The standard finite-difference equations were obtained by starting with an expansion of the neutron current in powers of the mesh size, h, and keeping terms as far as h 2 . It was confirmed that these equations led to the well-known result that the criticality parameter varied with the square of the mesh size. An improved form of the finite-difference equations was obtained by continuing the expansion for the neutron current as far as the term in h 4 . In this case, the critical parameter varied as the fourth power of the mesh size. The finite-element solutions for 2 and 3 nodes per element revealed that the criticality parameter varied as the square and fourth power of the mesh size, respectively. Numerical results are presented for a bare reactive core of uniform composition with 2 zones of different uniform mesh and for a reactive core with an absorptive reflector. (author)

Study of the 2004 End-Cap beam tests of the ATLAS detector

CERN Document Server

Bieri, Marco

The ATLAS detector is an all-purpose detector to study high-ener gy proton–proton colli- sions. ATLAS is located at the LHC (Lar ge Hadron Collider) at CERN in Gene va, Switzer - land. Before first data taking, man y beam tests have been carried out in order to fully understand each detector component. The studies in this thesis will concentrate on the 2004 beam test of the entire combined end-cap calorimeter system. The first section of this thesis outlines particle selection in the incoming test beam, eliminating contamination in order to have an accurate calibration environment. The remainder of the thesis focuses on detector calibration and performance studies, including signal-to-ener gy calibration con- stant determination, and various detector ener gy summation methods studying their effect on response. Ov erall detector ener gy sharing characteristics including the response of dead detector regions is also presented.

Multiphase poroelastic finite element models for soft tissue structures

International Nuclear Information System (INIS)

Simon, B.R.

1992-01-01

During the last two decades, biological structures with soft tissue components have been modeled using poroelastic or mixture-based constitutive laws, i.e., the material is viewed as a deformable (porous) solid matrix that is saturated by mobile tissue fluid. These structures exhibit a highly nonlinear, history-dependent material behavior; undergo finite strains; and may swell or shrink when tissue ionic concentrations are altered. Give the geometric and material complexity of soft tissue structures and that they are subjected to complicated initial and boundary conditions, finite element models (FEMs) have been very useful for quantitative structural analyses. This paper surveys recent applications of poroelastic and mixture-based theories and the associated FEMs for the study of the biomechanics of soft tissues, and indicates future directions for research in this area. Equivalent finite-strain poroelastic and mixture continuum biomechanical models are presented. Special attention is given to the identification of material properties using a porohyperelastic constitutive law ans a total Lagrangian view for the formulation. The associated FEMs are then formulated to include this porohyperelastic material response and finite strains. Extensions of the theory are suggested in order to include inherent viscoelasticity, transport phenomena, and swelling in soft tissue structures. A number of biomechanical research areas are identified, and possible applications of the porohyperelastic and mixture-based FEMs are suggested. 62 refs., 11 figs., 3 tabs

Finite rate chemistry for USA-series codes - rormulation and applications

International Nuclear Information System (INIS)

Palaniswamy, S.; Chakravarthy, S.R.; Ota, D.K.

1989-01-01

The USA-series of CFD codes are based on unified solution algorithms including explicit and implicit formulations, factorization and relaxation approaches, time marching and space marching methodologies, etc., in order to be able to solve a very wide class of CFD problems using a single framework. Euler or Navier-Stokes equations are solved using a finite-volume treatment with upwind Total Variation Diminishing discretization for the inviscid terms. Recently, these codes have been enlarged to also unify different aerothermodynamic options (perfect gas, real gas including equilibrium and nonequlibrium chemistry). This paper describes aspects of the finite-rate-chemistry capability. 27 references

Recent developments in radiation detectors and instruments

International Nuclear Information System (INIS)

Das, Debashis

2016-01-01

Radiation detector is the key component in precise and accurate measurement of the nuclear radiations. The detectors deployed for radiation measurements in broadly classified sectors of Energy, Security, Discovery Science and Health and Environments are in general specific to their applications. The nuclear reactors as well as the fuel processing including waste management in energy sector require wide range/variety of detectors and the instruments for safe and precise generation of power. The security sector has gained importance in radiation monitoring in the present security perspective and there are many challenges in development of detector technology. The Discovery Science or the mega science projects viz CERN, Fermilab, GANIL, INO, MACE telescope, ITER etc have continuously generated new demand on detector related technologies that have been also found to be useful in other applications. Similarly, the health and environment monitoring have been also evolving with new technologies and techniques to address the requirement's arising in projects of new nuclear programs

Representation theory of finite monoids

CERN Document Server

Steinberg, Benjamin

2016-01-01

This first text on the subject provides a comprehensive introduction to the representation theory of finite monoids. Carefully worked examples and exercises provide the bells and whistles for graduate accessibility, bringing a broad range of advanced readers to the forefront of research in the area. Highlights of the text include applications to probability theory, symbolic dynamics, and automata theory. Comfort with module theory, a familiarity with ordinary group representation theory, and the basics of Wedderburn theory, are prerequisites for advanced graduate level study. Researchers in algebra, algebraic combinatorics, automata theory, and probability theory, will find this text enriching with its thorough presentation of applications of the theory to these fields. Prior knowledge of semigroup theory is not expected for the diverse readership that may benefit from this exposition. The approach taken in this book is highly module-theoretic and follows the modern flavor of the theory of finite dimensional ...

Quantitative comparison using Generalized Relative Object Detectability (G-ROD) metrics of an amorphous selenium detector with high resolution Microangiographic Fluoroscopes (MAF) and standard flat panel detectors (FPD).

Science.gov (United States)

Russ, M; Shankar, A; Jain, A; Setlur Nagesh, S V; Ionita, C N; Scott, C; Karim, K S; Bednarek, D R; Rudin, S

2016-02-27

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25 μ m pixel pitch, and 1000 μ m thick a-Se layer operating at 10V/ μ m bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-prewhitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal-spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide breakthrough abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices.

Nilpotent -local finite groups

Science.gov (United States)

Cantarero, José; Scherer, Jérôme; Viruel, Antonio

2014-10-01

We provide characterizations of -nilpotency for fusion systems and -local finite groups that are inspired by known result for finite groups. In particular, we generalize criteria by Atiyah, Brunetti, Frobenius, Quillen, Stammbach and Tate.

Radiation effects on light sources and detectors

International Nuclear Information System (INIS)

Barnes, C.E.

1985-01-01

The rapidly expanding field of optoelectronics includes a wide variety of both military and non-military applications in which the systems must meet radiation exposure requirements. Herein, we review the work on radiation effects on sources and detectors for such optoelectronic systems. For sources the principal problem is permanent damage-induced light output degradation, while for detectors it is ionizing radiation-induced photocurrents

Compound Semiconductor Radiation Detector

International Nuclear Information System (INIS)

Kim, Y. K.; Park, S. H.; Lee, W. G.; Ha, J. H.

2005-01-01

In 1945, Van Heerden measured α, β and γ radiations with the cooled AgCl crystal. It was the first radiation measurement using the compound semiconductor detector. Since then the compound semiconductor has been extensively studied as radiation detector. Generally the radiation detector can be divided into the gas detector, the scintillator and the semiconductor detector. The semiconductor detector has good points comparing to other radiation detectors. Since the density of the semiconductor detector is higher than that of the gas detector, the semiconductor detector can be made with the compact size to measure the high energy radiation. In the scintillator, the radiation is measured with the two-step process. That is, the radiation is converted into the photons, which are changed into electrons by a photo-detector, inside the scintillator. However in the semiconductor radiation detector, the radiation is measured only with the one-step process. The electron-hole pairs are generated from the radiation interaction inside the semiconductor detector, and these electrons and charged ions are directly collected to get the signal. The energy resolution of the semiconductor detector is generally better than that of the scintillator. At present, the commonly used semiconductors as the radiation detector are Si and Ge. However, these semiconductor detectors have weak points. That is, one needs thick material to measure the high energy radiation because of the relatively low atomic number of the composite material. In Ge case, the dark current of the detector is large at room temperature because of the small band-gap energy. Recently the compound semiconductor detectors have been extensively studied to overcome these problems. In this paper, we will briefly summarize the recent research topics about the compound semiconductor detector. We will introduce the research activities of our group, too

Pulse shape analysis optimization with segmented HPGe-detectors

Energy Technology Data Exchange (ETDEWEB)

Lewandowski, Lars; Birkenbach, Benedikt; Reiter, Peter [Institute for Nuclear Physics, University of Cologne (Germany); Bruyneel, Bart [CEA, Saclay (France); Collaboration: AGATA-Collaboration

2014-07-01

Measurements with the position sensitive, highly segmented AGATA HPGe detectors rely on the gamma-ray-tracking GRT technique which allows to determine the interaction point of the individual gamma-rays hitting the detector. GRT is based on a pulse shape analysis PSA of the preamplifier signals from the 36 segments and the central electrode of the detector. The achieved performance and position resolution of the AGATA detector is well within the specifications. However, an unexpected inhomogeneous distribution of interaction points inside the detector volume is observed as a result of the PSA even when the measurement is performed with an isotropically radiating gamma ray source. The clustering of interaction points motivated a study in order to optimize the PSA algorithm or its ingredients. Position resolution results were investigated by including contributions from differential crosstalk of the detector electronics, an improved preamplifier response function and a new time alignment. Moreover the spatial distribution is quantified by employing different χ{sup 2}-minimization procedures.

Experiences with radiation portal detectors for international rail transport

International Nuclear Information System (INIS)

Stromswold, David C.; McCormick, Kathleen R.; Todd, Lindsay C.; Ashbaker, Eric D.; Evans, J.C.

2006-01-01

Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm x 10-cm x 41-cm) and a PVT panel with a 41 cm x 173 cm x 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars creates a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site the trains carried inter-modal containers that had been unloaded from ships, and at the other site the trains contained bulk cargo or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting program GADRAS/FitToDB from Sandia National Laboratories. For much of the NORM the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases

Cherenkov Ring Imaging Detector front-end electronics

International Nuclear Information System (INIS)

Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Marshall, D.; Muller, D.; Nagamine, T.; Oxoby, G.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Suekane, F.; Toge, N.; Va'Vra, J.; Williams, S.; Wilson, R.J.; Whitaker, J.S.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Morrison, R.; Witherell, M.; Yellin, S.; Coyle, P.; Coyne, D.; Spencer, E.; d'Oliveira, A.; Johnson, R.A.; Martinez, J.; Nussbaum, M.; Santha, A.K.S.; Shoup, A.; Stockdale, I.; Jacques, P.; Plano, R.; Stamer, P.; Abe, K.; Hasegawa, K.; Yuta, H.

1990-10-01

The SLD Cherenkov Ring Imaging Detector use a proportional wire detector for which a single channel hybrid has been developed. It consists of a preamplifier, gain selectable amplifier, load driver amplifier, power switching, and precision calibrator. For this hybrid, a bipolar, semicustom integrated circuit has been designed which includes video operational amplifiers for two of the gain stages. This approach allows maximization of the detector volume, allows DC coupling, and enables gain selection. System tests show good noise performance, calibration precision, system linearity, and signal shape uniformity over the full dynamic range. 10 refs., 8 figs

Fast timing methods for semiconductor detectors. Revision

International Nuclear Information System (INIS)

Spieler, H.

1984-10-01

This tutorial paper discusses the basic parameters which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter

The GRANDE detector

International Nuclear Information System (INIS)

Adams, A.; Bond, R.; Coleman, L.; Rollefson, A.; Wold, D.; Bratton, C.B.; Gurr, H.; Kropp, W.; Nelson, M.; Price, L.R.; Reines, F.; Schultz, J.; Sobel, H.; Svoboda, R.; Yodh, G.; Burnett, T.; Chaloupka, V.; Wilkes, R.J.; Cherry, M.; Ellison, S.B.; Guzik, T.G.; Wefel, J.; Gaidos, J.; Loeffler, F.; Sembroski, G.; Wilson, C.; Goodman, J.; Haines, T.J.; Kielczewska, D.; Lane, C.; Steinberg, R.; Lieber, M.; Nagle, D.; Potter, M.; Tripp, R.

1990-01-01

In this paper we present a detector facility which meets the requirements outlined above for a next-generation instrument. GRANDE (Gamma Ray and Neutrino DEtector) is an imaging, water Cerenkov detector, which combines in one facility an extensive air shower array and a high-energy neutrino detector. (orig.)

Coupled porohyperelastic mass transport (PHEXPT) finite element models for soft tissues using ABAQUS.

Science.gov (United States)

Vande Geest, Jonathan P; Simon, B R; Rigby, Paul H; Newberg, Tyler P

2011-04-01

Finite element models (FEMs) including characteristic large deformations in highly nonlinear materials (hyperelasticity and coupled diffusive/convective transport of neutral mobile species) will allow quantitative study of in vivo tissues. Such FEMs will provide basic understanding of normal and pathological tissue responses and lead to optimization of local drug delivery strategies. We present a coupled porohyperelastic mass transport (PHEXPT) finite element approach developed using a commercially available ABAQUS finite element software. The PHEXPT transient simulations are based on sequential solution of the porohyperelastic (PHE) and mass transport (XPT) problems where an Eulerian PHE FEM is coupled to a Lagrangian XPT FEM using a custom-written FORTRAN program. The PHEXPT theoretical background is derived in the context of porous media transport theory and extended to ABAQUS finite element formulations. The essential assumptions needed in order to use ABAQUS are clearly identified in the derivation. Representative benchmark finite element simulations are provided along with analytical solutions (when appropriate). These simulations demonstrate the differences in transient and steady state responses including finite deformations, total stress, fluid pressure, relative fluid, and mobile species flux. A detailed description of important model considerations (e.g., material property functions and jump discontinuities at material interfaces) is also presented in the context of finite deformations. The ABAQUS-based PHEXPT approach enables the use of the available ABAQUS capabilities (interactive FEM mesh generation, finite element libraries, nonlinear material laws, pre- and postprocessing, etc.). PHEXPT FEMs can be used to simulate the transport of a relatively large neutral species (negligible osmotic fluid flux) in highly deformable hydrated soft tissues and tissue-engineered materials.

Detectors - Electronics

International Nuclear Information System (INIS)

Bregeault, J.; Gabriel, J.L.; Hierle, G.; Lebotlan, P.; Leconte, A.; Lelandais, J.; Mosrin, P.; Munsch, P.; Saur, H.; Tillier, J.

1998-01-01

The reports presents the main results obtained in the fields of radiation detectors and associated electronics. In the domain of X-ray gas detectors for the keV range efforts were undertaken to rise the detector efficiency. Multiple gap parallel plate chambers of different types as well as different types of X → e - converters were tested to improve the efficiency (values of 2.4% at 60 KeV were reached). In the field of scintillators a study of new crystals has been carried out (among which Lutetium orthosilicate). CdTe diode strips for obtaining X-ray imaging were studied. The complete study of a linear array of 8 CdTe pixels has been performed and certified. The results are encouraging and point to this method as a satisfying solution. Also, a large dimension programmable chamber was used to study the influence of temperature on the inorganic scintillators in an interval from -40 deg. C to +150 deg. C. Temperature effects on other detectors and electronic circuits were also investigated. In the report mentioned is also the work carried out for the realization of the DEMON neutron multidetector. For neutron halo experiments different large area Si detectors associated with solid and gas position detectors were realized. In the frame of a contract with COGEMA a systematic study of Li doped glasses was undertaken aiming at replacing with a neutron probe the 3 He counters presently utilized in pollution monitoring. An industrial prototype has been realised. Other studies were related to integrated analog chains, materials for Cherenkov detectors, scintillation probes for experiments on fundamental processes, gas position sensitive detectors, etc. In the field of associated electronics there are mentioned the works related to the multidetector INDRA, data acquisition, software gamma spectrometry, automatic gas pressure regulation in detectors, etc

Evaluation of Concrete Cylinder Tests Using Finite Elements

DEFF Research Database (Denmark)

Saabye Ottosen, Niels

1984-01-01

Nonlinear axisymmetric finite element analyses are performed on the uniaxial compressive test of concrete cylinders. The models include thick steel loading plates, and cylinders with height‐to‐diameter ratios (h/d) ranging from 1‐3 are treated. A simple constitutive model of the concrete is emplo......Nonlinear axisymmetric finite element analyses are performed on the uniaxial compressive test of concrete cylinders. The models include thick steel loading plates, and cylinders with height‐to‐diameter ratios (h/d) ranging from 1‐3 are treated. A simple constitutive model of the concrete...... uniaxial strength the use of geometrically matched loading plates seems to be advantageous. Finally, it is observed that for variations of the element size within limits otherwise required to obtain a realistic analysis, the results are insensitive to the element size....

Radially dependent photopeak efficiency model for Si(Li) detectors

Energy Technology Data Exchange (ETDEWEB)

Cohen, D D [Australian Inst. of Nuclear Science and Engineering, Lucas Heights

1980-12-15

A simple five parameter model for the efficiency of a Si(Li) detector has been developed. It was found necessary to include a radially dependent efficiency even for small detectors. The model is an extension of the pioneering work of Hansen et al. but correction factors include more up to date data and explicit equations for the mass attenuation coefficients over a wide range of photons energies. Four of the five parameters needed are generally supplied by most commercial manufacturers of Si(Li) detectors. /sup 54/Mn and /sup 241/Am sources have been used to calibrate a Si(Li) to approx. +-3% over the energy range 3-60 keV.

Commissioning of the Absolute Luminosity For ATLAS Detector at the LHC

DEFF Research Database (Denmark)

Jakobsen, Sune

To determine the total cross section and absolute luminosity in the ATLAS detector at the LHC via pp scattering under very small angles, a dedicated sub-detector called ALFA has been made. Several performance evaluation tests including a test beam campaign lead to improvements of the detector...

Finite flavour groups of fermions

International Nuclear Information System (INIS)

Grimus, Walter; Ludl, Patrick Otto

2012-01-01

We present an overview of the theory of finite groups, with regard to their application as flavour symmetries in particle physics. In a general part, we discuss useful theorems concerning group structure, conjugacy classes, representations and character tables. In a specialized part, we attempt to give a fairly comprehensive review of finite subgroups of SO(3) and SU(3), in which we apply and illustrate the general theory. Moreover, we also provide a concise description of the symmetric and alternating groups and comment on the relationship between finite subgroups of U(3) and finite subgroups of SU(3). Although in this review we give a detailed description of a wide range of finite groups, the main focus is on the methods which allow the exploration of their different aspects. (topical review)

Semiconductor radiation detectors. Device physics

International Nuclear Information System (INIS)

Lutz, G.

2007-01-01

Starting from basic principles, the author, whose own contributions to these developments have been significant, describes the rapidly growing field of modern semiconductor detectors used for energy and position measurement radiation. This development was stimulated by requirements in elementary particle physics where it has led to important scientific discoveries. It has now spread to many other fields of science and technology. The book is written in a didactic way and includes an introduction to semiconductor physics. The working principles of semiconductor radiation detectors are explained in an intuitive way, followed by formal quantitative analysis. Broad coverage is also given to electronic signal readout and to the subject of radiation damage. The book is the first to comprehensively cover the semiconductor radiation detectors currently in use. It is useful as a teaching guide and as a reference work for research and applications. (orig.)

Comparison of phoswich and ARSA-type detectors for radioxenon measurements

International Nuclear Information System (INIS)

Ward, R.M.; Biegalski, S.R.F.; Hennig, W.

2009-01-01

The monitoring of atmospheric radioxenon to ensure compliance with the Comprehensive Nuclear Test Ban Treaty (CTBT) has driven the development of improved detectors for measuring xenon, including the development of a phoswich detector. This detector uses only one PMT to detect β-γ coincidence, thus greatly reducing the bulk and electronics of the detector in comparison to the ARSA-type detector. In this experiment, 135 Xe was produced through neutron activation and a phoswich detector was used to attain spectra from the gas. These results were compared to similar results from an ARSA-type β-γ coincidence spectrum. The spectral characteristics and resolution were compared for the coincidence and beta spectra. Using these metrics, the overall performance of the phoswich detector for β-γ coincidence of radioxenon was evaluated. (author)

Advances in dynamic relaxation techniques for nonlinear finite element analysis

International Nuclear Information System (INIS)

Sauve, R.G.; Metzger, D.R.

1995-01-01

Traditionally, the finite element technique has been applied to static and steady-state problems using implicit methods. When nonlinearities exist, equilibrium iterations must be performed using Newton-Raphson or quasi-Newton techniques at each load level. In the presence of complex geometry, nonlinear material behavior, and large relative sliding of material interfaces, solutions using implicit methods often become intractable. A dynamic relaxation algorithm is developed for inclusion in finite element codes. The explicit nature of the method avoids large computer memory requirements and makes possible the solution of large-scale problems. The method described approaches the steady-state solution with no overshoot, a problem which has plagued researchers in the past. The method is included in a general nonlinear finite element code. A description of the method along with a number of new applications involving geometric and material nonlinearities are presented. They include: (1) nonlinear geometric cantilever plate; (2) moment-loaded nonlinear beam; and (3) creep of nuclear fuel channel assemblies

Finite volume form factors in the presence of integrable defects

International Nuclear Information System (INIS)

Bajnok, Z.; Buccheri, F.; Hollo, L.; Konczer, J.; Takacs, G.

2014-01-01

We developed the theory of finite volume form factors in the presence of integrable defects. These finite volume form factors are expressed in terms of the infinite volume form factors and the finite volume density of states and incorporate all polynomial corrections in the inverse of the volume. We tested our results, in the defect Lee–Yang model, against numerical data obtained by truncated conformal space approach (TCSA), which we improved by renormalization group methods adopted to the defect case. To perform these checks we determined the infinite volume defect form factors in the Lee–Yang model exactly, including their vacuum expectation values. We used these data to calculate the two point functions, which we compared, at short distance, to defect CFT. We also derived explicit expressions for the exact finite volume one point functions, which we checked numerically. In all of these comparisons excellent agreement was found

Domain decomposition based iterative methods for nonlinear elliptic finite element problems

Energy Technology Data Exchange (ETDEWEB)

Cai, X.C. [Univ. of Colorado, Boulder, CO (United States)

1994-12-31

The class of overlapping Schwarz algorithms has been extensively studied for linear elliptic finite element problems. In this presentation, the author considers the solution of systems of nonlinear algebraic equations arising from the finite element discretization of some nonlinear elliptic equations. Several overlapping Schwarz algorithms, including the additive and multiplicative versions, with inexact Newton acceleration will be discussed. The author shows that the convergence rate of the Newton`s method is independent of the mesh size used in the finite element discretization, and also independent of the number of subdomains into which the original domain in decomposed. Numerical examples will be presented.

Operational Experience with the ATLAS Pixel Detector at LHC

CERN Document Server

Keil, M

2013-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus crucial for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via front-end chips bump-bonded to 1744 n-on-n silicon substrates. In this paper results from the successful operation of the Pixel Detector at the LHC will be presented, including calibration procedures, detector performance and measurements of radiation damage. The detector performance is excellent: more than 95% of the pixels are operational, noise occupancy and hit efficiency exceed the des...

Portable triple silicon detector telescope spectrometer for skin dosimetry

CERN Document Server

Helt-Hansen, J; Christensen, P

1999-01-01

The features of a newly developed portable beta telescope spectrometer are described. The detector probe uses three silicon detectors with the thickness: 50 mu m/150 mu m/7000 mu m covered by a 2 mu m thick titanium window. Rejection of photon contributions from mixed beta/photon exposures is achieved by coincidence requirements between the detector signals. The silicon detectors, together with cooling aggregate, bias supplies, preamplifiers and charge generation for calibration are contained in a handy detector probe. Through a 3- or 10-m cable the detector unit is connected to a compact, portable processing unit including a laptop computer executing control, monitor, histogram and display tasks. The use of digital signal processing at an early stage of the signal chain has facilitated the achievement of a compact, low-weight device. 256 channels are available for each of the three detectors. The LabVIEW sup T sup M software distributed by National Instruments was used for all program developments for the sp...

Organic Scintillator Detector Response Simulations with DRiFT

Energy Technology Data Exchange (ETDEWEB)

Andrews, Madison Theresa [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bates, Cameron Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mckigney, Edward Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rising, Michael Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pinilla, Maria Isabel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Solomon, Jr., Clell Jeffrey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sood, Avneet [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-12-19

Accurate detector modeling is a requirement to design systems in many non-proliferation scenarios; by determining a Detector’s Response Function (DRF) to incident radiation, it is possible characterize measurements of unknown sources. DRiFT is intended to post-process MCNP® output and create realistic detector spectra. Capabilities currently under development include the simulation of semiconductor, gas, and (as is discussed in this work) scintillator detector physics. Energy spectra and pulse shape discrimination (PSD) trends for incident photon and neutron radiation have been reproduced by DRiFT.

Instrumentation for Kinetic-Inductance-Detector-Based Submillimeter Radio Astronomy

Science.gov (United States)

Duan, Ran

A substantial amount of important scientific information is contained within astronomical data at the submillimeter and far-infrared (FIR) wavelengths, including information regarding dusty galaxies, galaxy clusters, and star-forming regions; however, these wavelengths are among the least-explored fields in astronomy because of the technological difficulties involved in such research. Over the past 20 years, considerable efforts have been devoted to developing submillimeter- and millimeter-wavelength astronomical instruments and telescopes. The number of detectors is an important property of such instruments and is the subject of the current study. Future telescopes will require as many as hundreds of thousands of detectors to meet the necessary requirements in terms of the field of view, scan speed, and resolution. A large pixel count is one benefit of the development of multiplexable detectors that use kinetic inductance detector (KID) technology. This dissertation presents the development of a KID-based instrument including a portion of the millimeter-wave bandpass filters and all aspects of the readout electronics, which together enabled one of the largest detector counts achieved to date in submillimeter-/millimeter-wavelength imaging arrays: a total of 2304 detectors. The work presented in this dissertation has been implemented in the MUltiwavelength Submillimeter Inductance Camera (MUSIC), a new instrument for the Caltech Submillimeter Observatory (CSO).

Process allowing the spectral compensation of semi-conductor nuclear detector

International Nuclear Information System (INIS)

L'Hote, J.P.

1987-01-01

The process includes a discriminator whose threshold level is applied to the detector during a fixed time and is externally controlled by a pre-programmed system; the different threshold levels and their application time to the detector are fixed by the nature of the used detector and by the tolerance allowed on the spectral response. The measurements made for each threshold level are corrected by a coefficient depending on the nature of the used detector and the tolerance on the spectral response [fr

Finite element computation of plasma equilibria

International Nuclear Information System (INIS)

Rivier, M.

1977-01-01

The applicability of the finite element method is investigated for the numerical solution of the nonlinear Grad-Shafranov equation with free boundary for the flux function of a plasma at equilibrium. This method is based on the case of variational principles and finite dimensional subspaces whose elements are piecewise polynomial functions obtained by a Lagrange type interpolation procedure over a triangulation of the domain. Two cases of plasma pressure (exponential and quadratic including a vacuum region) were examined. In both cases the nonuniqueness of the solutions was shown in exhibiting a deeper solution in the case of exponential pressure function, and a non-constant solution for a quadratic pressure function. In order to get this ''other'' solution, two linearization methods were tested with two different constraints. Different cross sections are investigated

Management of disused smoke detectors

International Nuclear Information System (INIS)

Lacroix, J.P.

2001-01-01

Full text: Smoke detectors containing radioisotopes with long half-life (such as 241 Am and 239 Pu), are widely used all over the world. Very small activities are required for this application but in each country, the smoke detectors are present by thousands. The volume of the radioactive sources being so small compared to the overall volume of the device, the volume reduction is the only responsible option for their management and storage. These sources, collected as such, require deep geological repository that so far are not operational anywhere. The conditioning and the packaging should try to meet the requirement for future repository. The National Institute for Radioelements, in Belgium, (IRE) has acquired a wide experience in the field of handling, conditioning and storage of disused smoke detectors and lightning preventers mainly based on 241 Am sources. Up to now, more than forty different types of smoke detectors were dismantled in the IRE facilities representing a total amount of more than 30,000 items. This report presents a practical management option for disused smoke detectors sources and provides an example of specific technical procedure for 241 Am sources handling and conditioning for long term storage. This management option does not request heavy infrastructure. For this reason this practical approach can be implemented in every waste treatment facility including those in the developing countries. (author)

A Vertex and Tracking Detector System for CLIC

CERN Document Server

AUTHOR|(SzGeCERN)718101

2017-01-01

The physics aims at the proposed future CLIC high-energy linear $e^+e^−$ collider pose challenging demands on the performance of the detector system. In particular the vertex and tracking detectors have to combine precision measurements with robustness against the expected high rates of beam-induced backgrounds. The requirements include ultra-low mass, facilitated by power pulsing and air cooling in the vertex-detector region, small cell sizes and precision hit timing at the few-ns level. A detector concept meeting these requirements has been developed and an integrated R&D program addressing the challenges is progressing in the areas of ultra-thin sensors and readout ASICs, interconnect technology, mechanical integration and cooling.

Finite Element Analysis of Circular Plate using SolidWorks

International Nuclear Information System (INIS)

Kang, Yeo Jin; Jhung, Myung Jo

2011-01-01

Circular plates are used extensively in mechanical engineering for nuclear reactor internal components. The examples in the reactor vessel internals are upper guide structure support plate, fuel alignment plate, lower support plate etc. To verify the structural integrity of these plates, the finite element analyses are performed, which require the development of the finite element model. Sometimes it is very costly and time consuming to make the model especially for the beginners who start their engineering job for the structural analysis, necessitating a simple method to develop the finite element model for the pursuing structural analysis. Therefore in this study, the input decks are generated for the finite element analysis of a circular plate as shown in Fig. 1, which can be used for the structural analysis such as modal analysis, response spectrum analysis, stress analysis, etc using the commercial program Solid Works. The example problems are solved and the results are included for analysts to perform easily the finite element analysis of the mechanical plate components due to various loadings. The various results presented in this study would be helpful not only for the benchmark calculations and results comparisons but also as a part of the knowledge management for the future generation of young designers, scientists and computer analysts

Detector Control System for the AFP detector in ATLAS experiment at CERN

Science.gov (United States)

Banaś, E.; Caforio, D.; Czekierda, S.; Hajduk, Z.; Olszowska, J.; Seabra, L.; Šícho, P.

2017-10-01

The ATLAS Forward Proton (AFP) detector consists of two forward detectors located at 205 m and 217 m on either side of the ATLAS experiment. The aim is to measure the momenta and angles of diffractively scattered protons. In 2016, two detector stations on one side of the ATLAS interaction point were installed and commissioned. The detector infrastructure and necessary services were installed and are supervised by the Detector Control System (DCS), which is responsible for the coherent and safe operation of the detector. A large variety of used equipment represents a considerable challenge for the AFP DCS design. Industrial Supervisory Control and Data Acquisition (SCADA) product Siemens WinCCOA, together with the CERN Joint Control Project (JCOP) framework and standard industrial and custom developed server applications and protocols are used for reading, processing, monitoring and archiving of the detector parameters. Graphical user interfaces allow for overall detector operation and visualization of the detector status. Parameters, important for the detector safety, are used for alert generation and interlock mechanisms.

Parallel iterative procedures for approximate solutions of wave propagation by finite element and finite difference methods

Energy Technology Data Exchange (ETDEWEB)

Kim, S. [Purdue Univ., West Lafayette, IN (United States)

1994-12-31

Parallel iterative procedures based on domain decomposition techniques are defined and analyzed for the numerical solution of wave propagation by finite element and finite difference methods. For finite element methods, in a Lagrangian framework, an efficient way for choosing the algorithm parameter as well as the algorithm convergence are indicated. Some heuristic arguments for finding the algorithm parameter for finite difference schemes are addressed. Numerical results are presented to indicate the effectiveness of the methods.

Silicon Telescope Detectors

CERN Document Server

Gurov, Yu B; Sandukovsky, V G; Yurkovski, J

2005-01-01

The results of research and development of special silicon detectors with a large active area ($> 8 cm^{2}$) for multilayer telescope spectrometers (fulfilled in the Laboratory of Nuclear Problems, JINR) are reviewed. The detector parameters are listed. The production of totally depleted surface barrier detectors (identifiers) operating under bias voltage two to three times higher than depletion voltage is described. The possibility of fabrication of lithium drifted counters with a very thin entrance window on the diffusion side of the detector (about 10--20 $\\mu$m) is shown. The detector fabrication technique has allowed minimizing detector dead regions without degradation of their spectroscopic characteristics and reliability during long time operation in charge particle beams.

Finite Discrete Gabor Analysis

DEFF Research Database (Denmark)

Søndergaard, Peter Lempel

2007-01-01

frequency bands at certain times. Gabor theory can be formulated for both functions on the real line and for discrete signals of finite length. The two theories are largely the same because many aspects come from the same underlying theory of locally compact Abelian groups. The two types of Gabor systems...... can also be related by sampling and periodization. This thesis extends on this theory by showing new results for window construction. It also provides a discussion of the problems associated to discrete Gabor bases. The sampling and periodization connection is handy because it allows Gabor systems...... on the real line to be well approximated by finite and discrete Gabor frames. This method of approximation is especially attractive because efficient numerical methods exists for doing computations with finite, discrete Gabor systems. This thesis presents new algorithms for the efficient computation of finite...

Finite-Element Modeling of Timber Joints with Punched Metal Plate Fasteners

DEFF Research Database (Denmark)

Ellegaard, Peter

2006-01-01

The focus of this paper is to describe the idea and the theory behind a finite-element model developed for analysis of timber trusses with punched metal plate fasteners (nail plates). The finite-element model includes the semirigid and nonlinear behavior of the joints (nonlinear nail and plate...... elements) and contact between timber beams, if any (bilinear contact elements). The timber beams have linear-elastic properties. The section forces needed for design of the joints are given directly by the finite-element model, since special elements are used to model the nail groups and the nail plate...... the behavior of the joints very well at lower load levels. At higher load levels the stiffness is overestimated due to development of cracks in the timber and the linear-elastic timber properties in the finite-element model....

Search for Physics beyond the Standard Model with the ATLAS detector and the development of radiation detectors

CERN Document Server

Silver, Yiftah

We are investigating a radiation detector based on plasma display panel technology, the principal component of plasma television displays. This Plasma Panel Sensor (PPS) technology is a variant of micro-pattern gas radiation detectors. Based on the properties of existing plasma display panels, we expect eventually to be able to build a sealed array of plasma discharge gas cells to detect ionizing radiation with fast rise time of less than 10ns and high spatial resolution using a pixel pitch of less than 100 micrometer. In this thesis I shall describe our program of testing plasma display panels as detectors, including simulations, design and the first laboratory and beam studies that demonstrate the detection of cosmic ray muons, beta rays and medium energy protons. The ATLAS detector is used to search for high-mass resonances, in particular heavy neutral gauge bosons (Z') and excited states of Kaluza-Klein γ/Z bosons decaying to an electron-positron pair or a muon-antimuon pair. Results are presented based ...

Recommended activation detector cross sections (RNDL-82)

International Nuclear Information System (INIS)

Bondars, Kh.Ya.; Lapenas, A.A.

1984-01-01

The results of the comparison between measured and calculated average cross sections in 5 benchmark experiments are presented. Calculations have been based on the data from 10 libraries of evaluated cross sections. The recommended library (RNDL-82) of the activation detector cross sections has been created on the basis of the comparison. RNDL-82, including 26 reactions, and the basic characteristics of the detectors are presented. (author)

High-energy detector

Science.gov (United States)

Bolotnikov, Aleksey E [South Setauket, NY; Camarda, Giuseppe [Farmingville, NY; Cui, Yonggang [Upton, NY; James, Ralph B [Ridge, NY

2011-11-22

The preferred embodiments are directed to a high-energy detector that is electrically shielded using an anode, a cathode, and a conducting shield to substantially reduce or eliminate electrically unshielded area. The anode and the cathode are disposed at opposite ends of the detector and the conducting shield substantially surrounds at least a portion of the longitudinal surface of the detector. The conducting shield extends longitudinally to the anode end of the detector and substantially surrounds at least a portion of the detector. Signals read from one or more of the anode, cathode, and conducting shield can be used to determine the number of electrons that are liberated as a result of high-energy particles impinge on the detector. A correction technique can be implemented to correct for liberated electron that become trapped to improve the energy resolution of the high-energy detectors disclosed herein.

Review of the Radiation Environment in the Inner Detector

CERN Document Server

Dawson, I

2000-01-01

The radiation environment in the inner detector has been simulated using the particle transport program FLUKA with a recent description of the ATLAS experiment. Given in this note are particle fluences and doses at positions relevant to the PIXEL, SCT and TRT detectors. In addition, studies are reported on in which 1) information concerning the optimisation of the inner detector neutron-moderators is obtained and 2) the impact of including additional vacuum-equipment is assessed.

Massively Parallel Finite Element Programming

KAUST Repository

Heister, Timo; Kronbichler, Martin; Bangerth, Wolfgang

2010-01-01

Today's large finite element simulations require parallel algorithms to scale on clusters with thousands or tens of thousands of processor cores. We present data structures and algorithms to take advantage of the power of high performance computers in generic finite element codes. Existing generic finite element libraries often restrict the parallelization to parallel linear algebra routines. This is a limiting factor when solving on more than a few hundreds of cores. We describe routines for distributed storage of all major components coupled with efficient, scalable algorithms. We give an overview of our effort to enable the modern and generic finite element library deal.II to take advantage of the power of large clusters. In particular, we describe the construction of a distributed mesh and develop algorithms to fully parallelize the finite element calculation. Numerical results demonstrate good scalability. © 2010 Springer-Verlag.

Massively Parallel Finite Element Programming

KAUST Repository

Heister, Timo

2010-01-01

Today\\'s large finite element simulations require parallel algorithms to scale on clusters with thousands or tens of thousands of processor cores. We present data structures and algorithms to take advantage of the power of high performance computers in generic finite element codes. Existing generic finite element libraries often restrict the parallelization to parallel linear algebra routines. This is a limiting factor when solving on more than a few hundreds of cores. We describe routines for distributed storage of all major components coupled with efficient, scalable algorithms. We give an overview of our effort to enable the modern and generic finite element library deal.II to take advantage of the power of large clusters. In particular, we describe the construction of a distributed mesh and develop algorithms to fully parallelize the finite element calculation. Numerical results demonstrate good scalability. © 2010 Springer-Verlag.

Operating Instructions for the Cryogenics in the Liquid Argon Detector at CIEMAT; Operacion de la Criogenia del Detector de Argon Liquido del CIEMAT

Energy Technology Data Exchange (ETDEWEB)

Romero, L; Leal, M D; Prado, M del; Ramirez, J L

2009-12-19

Ciemat has wide experience in designing and developing gaseous particle detectors. It has taken part in the building of experiments for CERN accelerators, constructing shares of the muon chambers for L3 experiment in LEP and CMS experiment in LHC. Recently, new concepts for particle detectors have been developed, as a natural evolution from the ones built at Ciemat. These new radiation detectors use liquefied noble gases as active media. A testing system for these kind of liquefied argon detectors has been built at Ciemat, and includes a supporting cryogenic system for the liquefaction and maintenance of the liquid argon needed for operating the detector. This document describes the technical features of this cryogenic system. Besides the documentation of the cryogenic system, this technical report can be of help for the management and upgrading of the detector. As well as an introduction, the report includes the following chapters: The second one is a description of the cryogenics and gas systems. The third chapter shows the controlling electronics. The fourth chapter deals with the important topic that is security, its systems and protocols. The fifth describes the cryogenic operations possible in this equipment. The report is completed with diagrams, schemes, pictures and tables for the easier management of the setup. (Author)

Nuclear radiation detectors

International Nuclear Information System (INIS)

Kapoor, S.S.; Ramamurthy, V.S.

1986-01-01

The present monograph is intended to treat the commonly used detectors in the field of nuclear physics covering important developments of the recent years. After a general introduction, a brief account of interaction of radiation with matter relevant to the processes in radiation detection is given in Chapter II. In addition to the ionization chamber, proportional counters and Geiger Mueller counters, several gas-filled detectors of advanced design such as those recently developed for heavy ion physics and other types of studies have been covered in Chapter III. Semiconductor detectors are dealt with in Chapter IV. The scintillation detectors which function by sensing the photons emitted by the luminescence process during the interaction of the impinging radiation with the scintillation detector medium are described in Chapter V. The topic of neutron detectors is covered in Chapter VI, as in this case the emphasis is more on the method of neutron detection rather than on detector type. Electronic instrumentation related to signal pulse processing dealt with in Chapter VII. The track etch detectors based on the visualization of the track of the impinging charge particle have also been briefly covered in the last chapter. The scope of this monograph is confined to detectors commonly used in low and medium energy nuclear physics research and applications of nuclear techniques. The monograph is intended for post-graduate students and those beginning to work with the radiation detectors. (author)

Radiation detectors laboratory

International Nuclear Information System (INIS)

Ramirez J, F.J.

1997-01-01

The Radiation detectors laboratory was established with the assistance of the International Atomic Energy Agency which gave this the responsibility to provide its services at National and regional level for Latin America and it is located at the ININ. The more expensive and delicate radiation detectors are those made of semiconductor, so it has been put emphasis in the use and repairing of these detectors type. The supplied services by this laboratory are: selection consultant, detectors installation and handling and associated systems. Installation training, preventive and corrective maintenance of detectors and detection systems calibration. (Author)

Advanced Detectors for Nuclear, High Energy and Astroparticle Physics

CERN Document Server

Das, Supriya; Ghosh, Sanjay

2018-01-01

The book presents high-quality papers presented at a national conference on ‘Advanced Detectors for Nuclear, High Energy and Astroparticle Physics’. The conference was organized to commemorate 100 years of Bose Institute. The book is based on the theme of the conference and provides a clear picture of basics and advancement of detectors for nuclear physics, high-energy physics and astroparticle physics together. The topics covered in the book include detectors for accelerator-based high energy physics; detectors for non-accelerator particle physics; nuclear physics detectors; detection techniques in astroparticle physics and dark matter; and applications and simulations. The book will be a good reference for researchers and industrial personnel working in the area of nuclear and astroparticle physics.

Ionization dual-zone static detector having single radioactive source

International Nuclear Information System (INIS)

Ried, L. Jr.; Wade, A.L.

1977-01-01

This ionization detector or combustion product detector includes a single radioactive source located in an ionization chamber, and the ionization chamber includes portions comprising a reference zone and a signal zone. Electrical circuitry connected to the reference and signal zones provides an output signal directly related to changes in voltages across the signal zone in relation to the amount of particulates of combustion present in the ionization chamber

On fracture in finite strain gradient plasticity

DEFF Research Database (Denmark)

Martínez Pañeda, Emilio; Niordson, Christian Frithiof

2016-01-01

In this work a general framework for damage and fracture assessment including the effect of strain gradients is provided. Both mechanism-based and phenomenological strain gradient plasticity (SGP) theories are implemented numerically using finite deformation theory and crack tip fields are invest......In this work a general framework for damage and fracture assessment including the effect of strain gradients is provided. Both mechanism-based and phenomenological strain gradient plasticity (SGP) theories are implemented numerically using finite deformation theory and crack tip fields...... are investigated. Differences and similarities between the two approaches within continuum SGP modeling are highlighted and discussed. Local strain hardening promoted by geometrically necessary dislocations (GNDs) in the vicinity of the crack leads to much higher stresses, relative to classical plasticity...... in the multiple parameter version of the phenomenological SGP theory. Since this also dominates the mechanics of indentation testing, results suggest that length parameters characteristic of mode I fracture should be inferred from nanoindentation....

Amorphous silicon radiation detectors

Science.gov (United States)

Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

1992-01-01

Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

Experiences with radiation portal detectors for international rail transport

Science.gov (United States)

Stromswold, D. C.; McCormick, K.; Todd, L.; Ashbaker, E. D.; Evans, J. C.

2006-08-01

Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm × 10-cm × 41-cm) and a PVT panel with a 41 cm × 173 cm × 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars creates a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site, the trains carried inter-modal containers that had been unloaded from ships, and at the other site, the trains contained bulk cargo in tanker cars and hopper cars or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting portion of the program GADRAS developed at Sandia National Laboratories. For most of the NORM, the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases.

Biset functors for finite groups

CERN Document Server

Bouc, Serge

2010-01-01

This volume exposes the theory of biset functors for finite groups, which yields a unified framework for operations of induction, restriction, inflation, deflation and transport by isomorphism. The first part recalls the basics on biset categories and biset functors. The second part is concerned with the Burnside functor and the functor of complex characters, together with semisimplicity issues and an overview of Green biset functors. The last part is devoted to biset functors defined over p-groups for a fixed prime number p. This includes the structure of the functor of rational representations and rational p-biset functors. The last two chapters expose three applications of biset functors to long-standing open problems, in particular the structure of the Dade group of an arbitrary finite p-group.This book is intended both to students and researchers, as it gives a didactic exposition of the basics and a rewriting of advanced results in the area, with some new ideas and proofs.

Silicon microstrip detectors on 6'' technology

CERN Document Server

Bölla, G; Günther, M; Martignon, G; Bacchetta, N; Bisello, D; Leonardi, G L; Lucas, T; Wilburn, C

1999-01-01

The fabrication of microstrip detectors on 4'' high-resistivity wafers that allow for a maximum workable area of about 42 cm sup 2 has been well established. Using 6'' wafers the workable area increases up to 100 cm sup 2 (more than twice the area of a 4'' wafer) allowing a larger number of detectors to be processed at the same time on the same wafer resulting in a sizable reduction of cost. After a prototyping stage, the CDF silicon tracker upgrade is now receiving final production sensors from Micron Semiconductor Ltd. The performance of double-sided single-metal small stereo angle sensors for the CDF SVXII and ISL detectors has been studied. Results include probe station measurements and test beam results. The problems encountered from prototyping to the final devices are described. A brief overview of the response of the sensors to irradiation with gamma-rays and p sup + up to a dose of 0.5 Mrad (well above the doses expected during Run II of the Tevatron) is included. (author)

Empirical observations on the aging of flux detectors at Darlington

Energy Technology Data Exchange (ETDEWEB)

Banica, C. [Ontario Power Generation, Darlington Nuclear, Bowmanville, Ontario (Canada); Slovak, R. [Ontario Power Generation, IMandCS, Pickering, Ontario (Canada)

2011-07-01

In-core neutron flux detectors are used for protective and safety functions in the Darlington CANDU reactors. This paper presents observations to date regarding aging of detectors, including recent measurements of prompt fractions and lead cable behaviour during a reactor power rundown. Linear models have been used to estimate and predict the prompt fraction evolution in time using independent variables such as the integrated neutron flux at the detector location, the length of the detector lead cable and the residual current at near-zero flux. (author)

Hybrid finite difference/finite element solution method development for non-linear superconducting magnet and electrical circuit breakdown transient analysis

International Nuclear Information System (INIS)

Kraus, H.G.; Jones, J.L.

1986-01-01

The problem of non-linear superconducting magnet and electrical protection circuit system transients is formulated. To enable studying the effects of coil normalization transients, coil distortion (due to imbalanced magnetic forces), internal coil arcs and shorts, and other normal and off-normal circuit element responses, the following capabilities are included: temporal, voltage and current-dependent voltage sources, current sources, resistors, capacitors and inductors. The concept of self-mutual inductance, and the form of the associated inductance matrix, is discussed for internally shorted coils. This is a Kirchhoff's voltage loop law and Kirchhoff's current node law formulation. The non-linear integrodifferential equation set is solved via a unique hybrid finite difference/integral finite element technique. (author)

Operational issues of present ATLAS strip detector

CERN Document Server

Yacoob, S; The ATLAS collaboration

2013-01-01

Current results from the successful operation of the Semi-Conductor Tracker (SCT) Detector at the LHC and its status after three years of operation is presented. This note reports on the operation of the detector including an overview of the issues we encountered and the observation of significant increases in leakage currents from bulk damage due to non-ionising radiation, there have been a small number of significant changes effecting detector operation since the contribution to the previous conference in the series [1]. The main emphasis is given to the tracking performance of the SCT and the data quality during the many months of data-taking (the LHC delivered 47 pb

Drift Chambers detectors; Detectores de deriva

Energy Technology Data Exchange (ETDEWEB)

Duran, I; Martinez laso, L

1989-07-01

We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs.

Introduction to finite temperature and finite density QCD

International Nuclear Information System (INIS)

Kitazawa, Masakiyo

2014-01-01

It has been pointed out that QCD (Quantum Chromodynamics) in the circumstances of medium at finite temperature and density shows numbers of phenomena similar to the characteristics of solid state physics, e.g. phase transitions. In the past ten years, the very high temperature and density matter came to be observed experimentally at the heavy ion collisions. At the same time, the numerical QCD analysis at finite temperature and density attained quantitative level analysis possible owing to the remarkable progress of computers. In this summer school lecture, it has been set out to give not only the recent results, but also the spontaneous breaking of the chiral symmetry, the fundamental theory of finite temperature and further expositions as in the following four sections. The first section is titled as 'Introduction to Finite Temperature and Density QCD' with subsections of 1.1 standard model and QCD, 1.2 phase transition and phase structure of QCD, 1.3 lattice QCD and thermodynamic quantity, 1.4 heavy ion collision experiments, and 1.5 neutron stars. The second one is 'Equilibrium State' with subsections of 2.1 chiral symmetry, 2.2 vacuum state: BCS theory, 2.3 NJL (Nambu-Jona-Lasinio) model, and 2.4 color superconductivity. The third one is 'Static fluctuations' with subsections of 3.1 fluctuations, 3.2 moment and cumulant, 3.3 increase of fluctuations at critical points, 3.4 analysis of fluctuations by lattice QCD and Taylor expansion, and 3.5 experimental exploration of QCD phase structure. The fourth one is 'Dynamical Structure' with 4.1 linear response theory, 4.2 spectral functions, 4.3 Matsubara function, and 4.4 analyses of dynamical structure by lattice QCD. (S. Funahashi)

HPGe detectors long time behaviour in high-resolution γ spectrometry

International Nuclear Information System (INIS)

Sajo-Bohus, L.; Rosso, D.; Sajo Castelli, A.M.; Napoli, D.R.; Fioretto, E.; Menegazzo, R.; Barros, H.; Ur, C.A.; Palacios, D.; Liendo, J.

2011-01-01

A large set of data on long term performance of n-type HPGe detectors used in GASP, EUROBALL and CLARA γ spectrometers, as well as environmental measurements have been collected over two decades. In this paper a detailed statistical analysis of this data is given and detector long term behaviour is provided to the scientific community. We include failure, failure mode, repair frequency, repair outcome and its influence in the energy efficiency and energy resolution. A remarkable result is that the life span distribution is exponential. A detector's failure is a memory-less process, where a previous failure does not influence the upcoming one. Repaired spectrometers result in high reliability with deep implications in the management of large scale high-resolution gamma spectrometry related projects. Findings show that on average, detectors initial counting efficiency is slightly lower (∼2%) than that reported by the manufacturers and the repair process (including annealing) does not affect significantly the energy efficiency, even after a long period of use. Repaired detector energy resolution statistics show that the probability, that a repaired detector will be at least as good as it was originally, is more than 3/4.

X-CSIT: a toolkit for simulating 2D pixel detectors

Science.gov (United States)

Joy, A.; Wing, M.; Hauf, S.; Kuster, M.; Rüter, T.

2015-04-01

A new, modular toolkit for creating simulations of 2D X-ray pixel detectors, X-CSIT (X-ray Camera SImulation Toolkit), is being developed. The toolkit uses three sequential simulations of detector processes which model photon interactions, electron charge cloud spreading with a high charge density plasma model and common electronic components used in detector readout. In addition, because of the wide variety in pixel detector design, X-CSIT has been designed as a modular platform so that existing functions can be modified or additional functionality added if the specific design of a detector demands it. X-CSIT will be used to create simulations of the detectors at the European XFEL, including three bespoke 2D detectors: the Adaptive Gain Integrating Pixel Detector (AGIPD), Large Pixel Detector (LPD) and DePFET Sensor with Signal Compression (DSSC). These simulations will be used by the detector group at the European XFEL for detector characterisation and calibration. For this purpose, X-CSIT has been integrated into the European XFEL's software framework, Karabo. This will further make it available to users to aid with the planning of experiments and analysis of data. In addition, X-CSIT will be released as a standalone, open source version for other users, collaborations and groups intending to create simulations of their own detectors.

Segmentation of the Outer Contact on P-Type Coaxial Germanium Detectors

Energy Technology Data Exchange (ETDEWEB)

Hull, Ethan L.; Pehl, Richard H.; Lathrop, James R.; Martin, Gregory N.; Mashburn, R. B.; Miley, Harry S.; Aalseth, Craig E.; Hossbach, Todd W.

2006-09-21

Germanium detector arrays are needed for low-level counting facilities. The practical applications of such user facilities include characterization of low-level radioactive samples. In addition, the same detector arrays can also perform important fundamental physics measurements including the search for rare events like neutrino-less double-beta decay. Coaxial germanium detectors having segmented outer contacts will provide the next level of sensitivity improvement in low background measurements. The segmented outer detector contact allows performance of advanced pulse shape analysis measurements that provide additional background reduction. Currently, n-type (reverse electrode) germanium coaxial detectors are used whenever a segmented coaxial detector is needed because the outer boron (electron barrier) contact is thin and can be segmented. Coaxial detectors fabricated from p-type germanium cost less, have better resolution, and are larger than n-type coaxial detectors. However, it is difficult to reliably segment p-type coaxial detectors because thick (~1 mm) lithium-diffused (hole barrier) contacts are the standard outside contact for p-type coaxial detectors. During this Phase 1 Small Business Innovation Research (SBIR) we have researched the possibility of using amorphous germanium contacts as a thin outer contact of p-type coaxial detectors that can be segmented. We have developed amorphous germanium contacts that provide a very high hole barrier on small planar detectors. These easily segmented amorphous germanium contacts have been demonstrated to withstand several thousand volts/cm electric fields with no measurable leakage current (<1 pA) from charge injection over the hole barrier. We have also demonstrated that the contact can be sputter deposited around and over the curved outside surface of a small p-type coaxial detector. The amorphous contact has shown good rectification properties on the outside of a small p-type coaxial detector. These encouraging

Chemochromic Hydrogen Leak Detectors

Science.gov (United States)

Roberson, Luke; Captain, Janine; Williams, Martha; Smith, Trent; Tate, LaNetra; Raissi, Ali; Mohajeri, Nahid; Muradov, Nazim; Bokerman, Gary

2009-01-01

At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or

Cryogenic detectors

International Nuclear Information System (INIS)

Zehnder, A.

1987-01-01

Presently the development of new large scale detector systems, used in very high energy physics experiments, is very active. In the low energy range, the introduction of charge coupled devices allows improved spacial and energy resolution. In the keV region, high resolution can only be achieved via the well established diffraction spectrometers with the well-known disadvantage of a small throughput. There exist no efficient detectors for non-ionizing radiation such as coherent nuclear scattering of weakly interacting particles. The development of high resolution solid state detectors in the keV-region with the possibility of nuclear recoil detection is therefore highly desired. Such detectors applied in astro and particle physics would thus allow one to obtain new information not achievable otherwise. Three types of cryogenic detectors exist: Calorimeters/Bolometers. This type is sensitive to the produced excess phonons and measures the deposited energy by detecting the heat pulses. Excess charge carriers should be used to produce phonons. Tunneling junctions. This type is sensitive to excess charge produced by the Cooper pair breakup. Excess phonons should be used to break up Cooper pairs. Superheated superconducting granules (SSG). An SSG detector consists of granules, the metastability of which is disturbed by radiation. The Meissner effect then causes a change in the field distribution of the applied external field, which can be detected. The present paper discusses the basic principle of calorimetric and tunneling junction detectors and some of their applications. 26 refs., 7 figs., 1 tab

Design, calibration, and performance of the MINERvA detector

Energy Technology Data Exchange (ETDEWEB)

Aliaga, L. [Department of Physics, College of William and Mary, Williamsburg, VA 23187 (United States); Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima, Perú (Peru); Bagby, L.; Baldin, B. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Baumbaugh, A. [Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima, Perú (Peru); Bodek, A.; Bradford, R. [University of Rochester, Rochester, NY 14610 (United States); Brooks, W.K. [Departamento de Física, Universidad Técnica Federico Santa María, Avda. España 1680, Casilla 110-V, Valparaíso (Chile); Boehnlein, D. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Boyd, S. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Budd, H. [University of Rochester, Rochester, NY 14610 (United States); Butkevich, A. [Institute for Nuclear Research of the Russian Academy of Sciences, 117312 Moscow (Russian Federation); Martinez Caicedo, D.A.; Castromonte, C.M. [Hampton University, Department of Physics, Hampton, VA 23668 (United States); Christy, M.E. [Department of Physics, University of Minnesota – Duluth, Duluth, MN 55812 (United States); Chvojka, J. [University of Rochester, Rochester, NY 14610 (United States); Motta, H. da [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro, RJ 22290-180 (Brazil); and others

2014-04-11

The MINERvA experiment is designed to perform precision studies of neutrino-nucleus scattering using ν{sub μ} and ν{sup ¯}{sub μ} neutrinos incident at 1–20 GeV in the NuMI beam at Fermilab. This article presents a detailed description of the MINERvA detector and describes the ex situ and in situ techniques employed to characterize the detector and monitor its performance. The detector is composed of a finely segmented scintillator-based inner tracking region surrounded by electromagnetic and hadronic sampling calorimetry. The upstream portion of the detector includes planes of graphite, iron and lead interleaved between tracking planes to facilitate the study of nuclear effects in neutrino interactions. Observations concerning the detector response over sustained periods of running are reported. The detector design and methods of operation have relevance to future neutrino experiments in which segmented scintillator tracking is utilized.

Silicon Technologies for the CLIC Vertex Detector

CERN Document Server

Spannagel, Simon

2017-01-01

CLIC is a proposed linear e$^+$e$^−$ collider designed to provide particle collisions at center-of-mass energies of up to 3 TeV. Precise measurements of the properties of the top quark and the Higgs boson, as well as searches for Beyond the Standard Model physics require a highly performant CLIC detector. In particular the vertex detector must provide a single point resolution of only a few micrometers while not exceeding the envisaged material budget of around 0.2%$~X_0$ per layer. Beam-beam interactions and beamstrahlung processes impose an additional requirement on the timestamping capabilities of the vertex detector of about 10 ns. These goals can only be met by using novel techniques in the sensor and ASIC design as well as in the detector construction. The R&D program for the CLIC vertex detector explores various technologies in order to meet these demands. The feasibility of planar sensors with a thickness of 50–150$~\\mu$m, including different active edge designs, are evaluated using Timepix3 A...

Laminated Amorphous Silicon Neutron Detector (pre-print)

International Nuclear Information System (INIS)

McHugh, Harry; Branz, Howard; Stradins, Paul; Xu, Yueqin

2009-01-01

An internal R and D project was conducted at the Special Technologies Laboratory (STL) of National Security Technologies, LLC (NSTec), to determine the feasibility of developing a multi-layer boron-10 based thermal neutron detector using the amorphous silicon (AS) technology currently employed in the manufacture of liquid crystal displays. The boron-10 neutron reaction produces an alpha that can be readily detected. A single layer detector, limited to an approximately 2-micron-thick layer of boron, has a theoretical sensitivity of about 3%; hence a thin multi-layer device with high sensitivity can theoretically be manufactured from single layer detectors. Working with National Renewable Energy Laboratory (NREL), an AS PiN diode alpha detector was developed and tested. The PiN diode was deposited on a boron-10 coated substrate. Testing confirmed that the neutron sensitivity was nearly equal to the theoretical value of 3%. However, adhesion problems with the boron-10 coating prevented successful development of a prototype detector. Future efforts will include boron deposition work and development of integrated AS signal processing circuitry.

Electronics for the Si detectors in APEX

International Nuclear Information System (INIS)

Wilt, P.R.; Betts, R.R.; Freer, M.

1994-01-01

APEX (ATLAS Positron EXperiment), a collaborative effort of ANL, FSU, MSU/NSCL, Princeton, Queen's, Rochester, Washington and Yale, is an experiment to study positron and electron production in very heavy ion collisions. The electrons and positrons are detected with two detector arrays, each consisting of 216 1 mm thick Si PIN diodes, and their energy and time-of-flight are measured. The number of detectors and limited space made it necessary to develop a system that could efficiently process and transfer signals from the detectors to the charge sensing ADC's and data readout electronics as well as monitor the condition of the detectors. The discussion will cover the electronics designed for the Si detectors, including the charge amplifier, ''Mother board'' for the charge amplifiers, 8 channel Shaper, 16 channel Constant Fraction Discriminator (CFD), 16 channel Peak-to-FERA (PTF) and the integration of the CFD and PTF with Charge sensing ADC's. Function and performance of the individual modules as well as the system as a whole will be discussed

Modelling drawbeads with finite elements and verification

NARCIS (Netherlands)

Carleer, B.D.; Carleer, B.D.; Vreede, P.T.; Vreede, P.T.; Louwes, M.F.M.; Louwes, M.F.M.; Huetink, Han

1994-01-01

Drawbeads are commonly used in deep drawing processes to control the flow of the blank during the forming operation. In finite element simulations of deep drawing the drawbead geometries are seldom included because of the small radii; because of these small radii a very large number of elements is

Designs and finite geometries

CERN Document Server

1996-01-01

Designs and Finite Geometries brings together in one place important contributions and up-to-date research results in this important area of mathematics. Designs and Finite Geometries serves as an excellent reference, providing insight into some of the most important research issues in the field.

Digital readouts for large microwave low-temperature detector arrays

International Nuclear Information System (INIS)

Mazin, Benjamin A.; Day, Peter K.; Irwin, Kent D.; Reintsema, Carl D.; Zmuidzinas, Jonas

2006-01-01

Over the last several years many different types of low-temperature detectors (LTDs) have been developed that use a microwave resonant circuit as part of their readout. These devices include microwave kinetic inductance detectors (MKID), microwave SQUID readouts for transition edge sensors (TES), and NIS bolometers. Current readout techniques for these devices use analog frequency synthesizers and IQ mixers. While these components are available as microwave integrated circuits, one set is required for each resonator. We are exploring a new readout technique for this class of detectors based on a commercial-off-the-shelf technology called software defined radio (SDR). In this method a fast digital to analog (D/A) converter creates as many tones as desired in the available bandwidth. Our prototype system employs a 100MS/s 16-bit D/A to generate an arbitrary number of tones in 50MHz of bandwidth. This signal is then mixed up to the desired detector resonant frequency (∼10GHz), sent through the detector, then mixed back down to baseband. The baseband signal is then digitized with a series of fast analog to digital converters (80MS/s, 14-bit). Next, a numerical mixer in a dedicated integrated circuit or FPGA mixes the resonant frequency of a specified detector to 0Hz, and sends the complex detector output over a computer bus for processing and storage. In this paper we will report on our results in using a prototype system to readout a MKID array, including system noise performance, X-ray pulse response, and cross-talk measurements. We will also discuss how this technique can be scaled to read out many thousands of detectors

Thermal Properties of the Silicon Microstrip Endcap Detector

CERN Document Server

Feld, Lutz; Hammarström, R

1998-01-01

Irradiated silicon detectors must be cooled in order to guarantee stable short and long term operation. Using the SiF1 milestone prototype we have performed a detailed analysis of the thermal properties of the silicon microstrip endcap detector. The strongest constraint on the cooling system is shown to be set by the need to avoid thermal runaway of the silicon detectors. We show that, taking into account the radiation damage to the silicon after 10 years of LHC operation and including some safety margin, the detector will need a cooling fluid temperature of around -20 C. The highest temperature on the silicon will then be in the range -15 C to -10 C. This sets an upper limit on the ambient temperature in the tracker volume.

Reverse Engineering Integrated Circuits Using Finite State Machine Analysis

Energy Technology Data Exchange (ETDEWEB)

Oler, Kiri J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miller, Carl H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-04-12

In this paper, we present a methodology for reverse engineering integrated circuits, including a mathematical verification of a scalable algorithm used to generate minimal finite state machine representations of integrated circuits.

The DELPHI Detector (DEtector with Lepton Photon and Hadron Identification)

CERN Multimedia

Crawley, B; Munich, K; Mckay, R; Matorras, F; Joram, C; Malychev, V; Behrmann, A; Van dam, P; Drees, J K; Stocchi, A; Adam, W; Booth, P; Bilenki, M; Rosenberg, E I; Morton, G; Rames, J; Hahn, S; Cosme, G; Ventura, L; Marco, J; Tortosa martinez, P; Monge silvestri, R; Moreno, S; Phillips, H; Alekseev, G; Boudinov, E; Martinez rivero, C; Gitarskiy, L; Davenport, M; De clercq, C; Firestone, A; Myagkov, A; Belous, K; Haider, S; Hamilton, K M; Lamsa, J; Rahmani, M H; Malek, A; Hughes, G J; Peralta, L; Carroll, L; Fuster verdu, J A; Cossutti, F; Gorn, L; Yi, J I; Bertrand, D; Myatt, G; Richard, F; Shapkin, M; Hahn, F; Ferrer soria, A; Reinhardt, R; Renton, P; Sekulin, R; Timmermans, J; Baillon, P

2002-01-01

% DELPHI The DELPHI Detector (Detector with Lepton Photon and Hadron Identification) \\\\ \\\\DELPHI is a general purpose detector for physics at LEP on and above the Z$^0$, offering three-dimensional information on curvature and energy deposition with fine spatial granularity as well as identification of leptons and hadrons over most of the solid angle. A superconducting coil provides a 1.2~T solenoidal field of high uniformity. Tracking relies on the silicon vertex detector, the inner detector, the Time Projection Chamber (TPC), the outer detector and forward drift chambers. Electromagnetic showers are measured in the barrel with high granularity by the High Density Projection Chamber (HPC) and in the endcaps by $ 1 ^0 $~x~$ 1 ^0 $ projective towers composed of lead glass as active material and phototriode read-out. Hadron identification is provided mainly by liquid and gas Ring Imaging Counters (RICH). The instrumented magnet yoke serves for hadron calorimetry and as filter for muons, which are identified in t...

The physics and technology of Si and Ge detectors

International Nuclear Information System (INIS)

Stab, Lucien

Semiconductor physics fundamentals are recalled (energy levels in crystalline solids, level population, charge carrier transport) as an introduction to studying NP junction at thermal equilibrium, or reversly biased. The fabrication of semiconductor detectors including surface barrier detectors, implanted junctions, and lithium-drifted semiconductors is discussed [fr

Socio-economic applications of finite state mean field games

KAUST Repository

Gomes, Diogo A.

2014-10-06

In this paper, we present different applications of finite state mean field games to socio-economic sciences. Examples include paradigm shifts in the scientific community or consumer choice behaviour in the free market. The corresponding finite state mean field game models are hyperbolic systems of partial differential equations, for which we present and validate different numerical methods. We illustrate the behaviour of solutions with various numerical experiments,which show interesting phenomena such as shock formation. Hence, we conclude with an investigation of the shock structure in the case of two-state problems.

Optimization of Finite-Differencing Kernels for Numerical Relativity Applications

Directory of Open Access Journals (Sweden)

Roberto Alfieri

2018-05-01

Full Text Available A simple optimization strategy for the computation of 3D finite-differencing kernels on many-cores architectures is proposed. The 3D finite-differencing computation is split direction-by-direction and exploits two level of parallelism: in-core vectorization and multi-threads shared-memory parallelization. The main application of this method is to accelerate the high-order stencil computations in numerical relativity codes. Our proposed method provides substantial speedup in computations involving tensor contractions and 3D stencil calculations on different processor microarchitectures, including Intel Knight Landing.

Design and fabrication of a self-powered neutron detector

International Nuclear Information System (INIS)

Garcia Garcia, Florencio.

1979-01-01

Self powered neutron detectors are becoming more and more popular in reactor instrumentation. A fast response detector of this type was made at the Reactor Division, La Reina Nuclear Center in Santiago. Cobalt wire was the emitter, teflon the insulator and a stainless steel tubing was the collector. The overall dimensions of the detector are 6 mms diameter and 700 mms length. The irradiation tests, carried out at the Center's 5 Mw research reactor showed a very reasonably linear relation between current supplied by the detector and thermal neutron flux, over a range extending from 10 10 to 10 13 n/cm 2 x seg. These tests also showed a good agreement between calculated and measured current. The models used for the calculation of current are fully explained and they include some improvements over those that have been published recently. An important conclusion for the case of the cobalt detectors is that the wire's diameter must be at least 1 mm. in order to have a neutron induced current bigger than the parasitic components generated by indirect processes. Calculations for other emitters such as vanadium, silver and rhodum are also included. (EC)

A hybrid finite-volume and finite difference scheme for depth-integrated non-hydrostatic model

Science.gov (United States)

Yin, Jing; Sun, Jia-wen; Wang, Xing-gang; Yu, Yong-hai; Sun, Zhao-chen

2017-06-01

A depth-integrated, non-hydrostatic model with hybrid finite difference and finite volume numerical algorithm is proposed in this paper. By utilizing a fraction step method, the governing equations are decomposed into hydrostatic and non-hydrostatic parts. The first part is solved by using the finite volume conservative discretization method, whilst the latter is considered by solving discretized Poisson-type equations with the finite difference method. The second-order accuracy, both in time and space, of the finite volume scheme is achieved by using an explicit predictor-correction step and linear construction of variable state in cells. The fluxes across the cell faces are computed in a Godunov-based manner by using MUSTA scheme. Slope and flux limiting technique is used to equip the algorithm with total variation dimensioning property for shock capturing purpose. Wave breaking is treated as a shock by switching off the non-hydrostatic pressure in the steep wave front locally. The model deals with moving wet/dry front in a simple way. Numerical experiments are conducted to verify the proposed model.

Comparison of natural and synthetic diamond X-ray detectors

International Nuclear Information System (INIS)

Lansley, S. P.; Betzel, G.T.; Meyer, J.; Metcalf, P.; Reinisch, L.

2010-01-01

Full text: Diamond detectors are particularly well suited for dosimetry applications in radiotherapy for reasons including near-tissue equivalence and high-spatial resolu tion resulting from small sensitive volumes. However, these detectors have not become commonplace due to high cost and poor availability arising from the need for high quality diamond. We have fabricated relatively cheap detectors from commercially-available synthetic diamond fabricated using chemical vapour deposition. Here, we present a comparison of one of these detectors with the only commercially-available diamond-based detector (which uses a natural diamond crystal). Parameters such as the energy dependence and linearity of charge with dose were investigated at orthovoltage energies (50-250 kY), and dose-rate dependence of charge at linear accelerator energy (6 MY). The energy dependence of a synthetic diamond detector was similar to that of the natural diamond detector, albeit with slightly less variation across the energy range. Both detectors displayed a linear response S. P. Lansley () . G. T. Betzel . J. Meyer Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand e-mail: stuart.lansley canterbury.ac.nz S. P. Lansley The Macdiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, New Zealand P. Metcalfe Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia L. Reinisch Department of Physical and Earth Sciences, Jacksonville State University, Jacksonville, AL, USA with dose (at 100 kY) over the limited dose range used. The sensitivity of the synthetic diamond detector was 302 nC/Gy, compared to 294 nC/Gy measured for the natural diamond detector; however, this was obtained with a bias of 246.50 Y compared to a bias of 61.75 Y used for the natural diamond detector. The natural diamond detector exhibited a greater dependency on dose-rate than the syn thetic diamond detector. Overall

Analysis of the TMI-2 source range detector response

International Nuclear Information System (INIS)

Carew, J.F.; Diamond, D.J.; Eridon, J.M.

1980-01-01

In the first few hours following the TMI-2 accident large variations (factors of 10-100) in the source range (SR) detector response were observed. The purpose of this analysis was to quantify the various effects which could contribute to these large variations. The effects evaluated included the transmission of neutrons and photons from the core to detector and the reduction in the multiplication of the Am-Be startup sources, and subsequent reduction in SR detector response, due to core voiding. A one-dimensional ANISN slab model of the TMI-2 core, core externals, pressure vessel and containment has been constructed for calculation of the SR detector response and is presented

The hardware of the ATLAS Pixel Detector Control System

International Nuclear Information System (INIS)

Henss, T; Andreani, A; Boek, J; Boyd, G; Citterio, M; Einsweiler, K; Kersten, S; Kind, P; Lantzsch, K; Latorre, S; Maettig, P; Meroni, C; Sabatini, F; Schultes, J

2007-01-01

The innermost part of the ATLAS (A Toroidal LHC ApparatuS) experiment, which is currently under construction at the LHC (Large Hadron Collider), will be a silicon pixel detector comprised of 1744 individual detector modules. To operate these modules, the readout electronics, and other detector components, a complex power supply and control system is necessary. The specific powering and control requirements, as well as the custom made components of our power supply and control systems, are described. These include remotely programmable regulator stations, the power supply system for the optical transceivers, several monitoring units, and the Interlock System. In total, this comprises the Pixel Detector Control System (DCS)

International Large Detector. Letter of intent

Energy Technology Data Exchange (ETDEWEB)

Stoeck, Holger [Sydney Univ., NSW (Australia). Falkiner High Energy Physics Group; Bergauer, Thomas; Dragicevic, Marko [Oesterreichische Akademie der Wissenschaften, Vienna (AT). Inst. fuer Hochenergiephysik] (and others)

2010-07-01

own goals of detector technology development. Members of the detector concept groups participate in the R and D collaborations and make sure that the detector technologies are successfully applied to the detector concept designs. By the creation of the ILD concept group, the application efforts became more focused. Currently, the ILD management includes subdetector contacts who are also key members of the detector R and D collaborations. This scheme is working efficiently such that we can finish basic R and D in time for the Technical Design Report which is envisaged around 2012. Overall, the ILD group structure is efficient while keeping exibility and openness. Even though we are still short on person power and funding at this time, we believe that we are well positioned to successfully complete a technical design for a detector at the International Linear Collider. The ILD group is firmly committed to the ILD project. (orig.)

International Large Detector. Letter of intent

International Nuclear Information System (INIS)

Stoeck, Holger; Bergauer, Thomas; Dragicevic, Marko

2010-01-01

own goals of detector technology development. Members of the detector concept groups participate in the R and D collaborations and make sure that the detector technologies are successfully applied to the detector concept designs. By the creation of the ILD concept group, the application efforts became more focused. Currently, the ILD management includes subdetector contacts who are also key members of the detector R and D collaborations. This scheme is working efficiently such that we can finish basic R and D in time for the Technical Design Report which is envisaged around 2012. Overall, the ILD group structure is efficient while keeping exibility and openness. Even though we are still short on person power and funding at this time, we believe that we are well positioned to successfully complete a technical design for a detector at the International Linear Collider. The ILD group is firmly committed to the ILD project. (orig.)

Detector applications

International Nuclear Information System (INIS)

Pehl, R.H.

1977-10-01

Semiconductor detectors are now applied to a very wide range of problems. The combination of relatively low cost, excellent energy resolution, and simultaneous broad energy-spectrum analysis is uniquely suited to many applications in both basic and applied physics. Alternative techniques, such as magnetic spectrometers for charged-particle spectroscopy, while offering better energy resolution, are bulky, expensive, and usually far more difficult to use. Furthermore, they do not directly provide the broad energy-spectrum measurements easily accomplished using semiconductor detectors. Scintillation detectors, which are approximately equivalent to semiconductor detectors in convenience and cost, exhibit 10 to 100 times worse energy resolution. However, their high efficiency and large potential size recommend their use in some measurements

On determining dead layer and detector thicknesses for a position-sensitive silicon detector

Science.gov (United States)

Manfredi, J.; Lee, Jenny; Lynch, W. G.; Niu, C. Y.; Tsang, M. B.; Anderson, C.; Barney, J.; Brown, K. W.; Chajecki, Z.; Chan, K. P.; Chen, G.; Estee, J.; Li, Z.; Pruitt, C.; Rogers, A. M.; Sanetullaev, A.; Setiawan, H.; Showalter, R.; Tsang, C. Y.; Winkelbauer, J. R.; Xiao, Z.; Xu, Z.

2018-04-01

In this work, two particular properties of the position-sensitive, thick silicon detectors (known as the "E" detectors) in the High Resolution Array (HiRA) are investigated: the thickness of the dead layer on the front of the detector, and the overall thickness of the detector itself. The dead layer thickness for each E detector in HiRA is extracted using a measurement of alpha particles emitted from a 212Pb pin source placed close to the detector surface. This procedure also allows for energy calibrations of the E detectors, which are otherwise inaccessible for alpha source calibration as each one is sandwiched between two other detectors. The E detector thickness is obtained from a combination of elastically scattered protons and an energy-loss calculation method. Results from these analyses agree with values provided by the manufacturer.

A Minor Modification of Leading Edge Discriminator Circuitry with a Delay Line for Baseline Restoration of Scintillation Detectors

International Nuclear Information System (INIS)

Izumi, N

2003-01-01

Multi-channel neutron time-of-flight detector arrays LaNSA, T-ion, Medusa, and Mandala, have been used for neutron spectroscopy in inertial confinement fusion experiments. These multi-channel neutron detector arrays consist of many identical scintillation detectors (842 ∼ 1024 channel), data acquisition electronics (discriminators, time-to digital converters, and controller). Each detector element is operated in neutron counting mode. Time-of-flight of individual detected neutrons are recorded by time to digital converters. The energy of each detected neutrons is determined from its time-of-flight. The accurate time measurement (Δt ∼ 0.5 ns) and straightforward statistical features of the data obtained with these systems provides good integrity and reliability. The elements detector used in these systems are organic scintillators coupled with photo multiplier tubes. A scintillation detector operated in particle-counting mode requires finite recovery time after each detection event. The recovery time is determined by the time responses of scintillators, photo multiplier tubes, and the dead times of following discriminators and time-to digital converters. The harsh gamma ray background environment of fast ignitor experiments requires detectors that have fast recovery times. In high intensity laser experiments (I > 10 19 W/cm 2 ), strong gamma ray bursts are produced by relativistic laser plasma interactions. Prior to the neutron signal, these strong gamma ray bursts hit the detectors and interfere with the detection of following neutron signals. In these situations, the recovery time of the system after preceding gamma ray bursts is determined mainly by the base line shift of the PMT signal (due to slower decay components of scintillators ''after glow''). Discriminators cannot detect following signal pulses until the proceeding burst decays below its threshold voltage. The base line shift caused by the after glow prolongs the recovery time of the discriminators

Structural weights analysis of advanced aerospace vehicles using finite element analysis

Science.gov (United States)

Bush, Lance B.; Lentz, Christopher A.; Rehder, John J.; Naftel, J. Chris; Cerro, Jeffrey A.

1989-01-01

A conceptual/preliminary level structural design system has been developed for structural integrity analysis and weight estimation of advanced space transportation vehicles. The system includes a three-dimensional interactive geometry modeler, a finite element pre- and post-processor, a finite element analyzer, and a structural sizing program. Inputs to the system include the geometry, surface temperature, material constants, construction methods, and aerodynamic and inertial loads. The results are a sized vehicle structure capable of withstanding the static loads incurred during assembly, transportation, operations, and missions, and a corresponding structural weight. An analysis of the Space Shuttle external tank is included in this paper as a validation and benchmark case of the system.

ɛ-connectedness, finite approximations, shape theory and coarse graining in hyperspaces

Science.gov (United States)

Alonso-Morón, Manuel; Cuchillo-Ibanez, Eduardo; Luzón, Ana

2008-12-01

We use upper semifinite hyperspaces of compacta to describe ε-connectedness and to compute homology from finite approximations. We find a new connection between ε-connectedness and the so-called Shape Theory. We construct a geodesically complete R-tree, by means of ε-components at different resolutions, whose behavior at infinite captures the topological structure of the space of components of a given compact metric space. We also construct inverse sequences of finite spaces using internal finite approximations of compact metric spaces. These sequences can be converted into inverse sequences of polyhedra and simplicial maps by means of what we call the Alexandroff-McCord correspondence. This correspondence allows us to relate upper semifinite hyperspaces of finite approximation with the Vietoris-Rips complexes of such approximations at different resolutions. Two motivating examples are included in the introduction. We propose this procedure as a different mathematical foundation for problems on data analysis. This process is intrinsically related to the methodology of shape theory. This paper reinforces Robins’s idea of using methods from shape theory to compute homology from finite approximations.

The Era of Kilometer-Scale Neutrino Detectors

Directory of Open Access Journals (Sweden)

Francis Halzen

2013-01-01

Full Text Available Neutrino astronomy beyond the Sun was first imagined in the late 1950s; by the 1970s, it was realized that kilometer-scale neutrino detectors were required. The first such instrument, IceCube, transforms a cubic kilometer of deep and ultra-transparent Antarctic ice into a particle detector. KM3NeT, an instrument that aims to exploit several cubic kilometers of the deep Mediterranean sea as its detector medium, is in its final design stages. The scientific missions of these instruments include searching for sources of cosmic rays and for dark matter, observing Galactic supernova explosions, and studying the neutrinos themselves. Identifying the accelerators that produce Galactic and extragalactic cosmic rays has been a priority mission of several generations of high-energy gamma-ray and neutrino telescopes; success has been elusive so far. Detecting the gamma-ray and neutrino fluxes associated with cosmic rays reaches a new watershed with the completion of IceCube, the first neutrino detector with sensitivity to the anticipated fluxes. In this paper, we will first revisit the rationale for constructing kilometer-scale neutrino detectors. We will subsequently recall the methods for determining the arrival direction, energy and flavor of neutrinos, and will subsequently describe the architecture of the IceCube and KM3NeT detectors.

Report on Advanced Detector Development

Energy Technology Data Exchange (ETDEWEB)

James K. Jewell

2012-09-01

Neutron, gamma and charged particle detection improvements are key to supporting many of the foreseen measurements and systems envisioned in the R&D programs and the future fuel cycle requirements, such as basic nuclear physics and data, modeling and simulation, reactor instrumentation, criticality safety, materials management and safeguards. This task will focus on the developmental needs of the FCR&D experimental programs, such as elastic/inelastic scattering, total cross sections and fission neutron spectra measurements, and will leverage a number of existing neutron detector development efforts and programs, such as those at LANL, PNNL, INL, and IAC as well as those at many universities, some of whom are funded under NE grants and contracts. Novel materials and fabrication processes combined with state-of-the-art electronics and computing provide new opportunities for revolutionary detector systems that will be able to meet the high precision needs of the program. This work will be closely coordinated with the Nuclear Data Crosscut. The Advanced Detector Development effort is a broadly-focused activity that supports the development of improved nuclear data measurements and improved detection of nuclear reactions and reactor conditions. This work supports the design and construction of large-scale, multiple component detectors to provide nuclear reaction data of unprecedented quality and precision. Examples include the Time Projection Chamber (TPC) and the DANCE detector at LANL. This work also supports the fabrication and end-user application of novel scintillator materials detection and monitoring.

Detector Control System for the AFP detector in ATLAS experiment at CERN

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00211068; The ATLAS collaboration; Caforio, Davide; Czekierda, Sabina; Hajduk, Zbigniew; Olszowska, Jolanta; Oleiro Seabra, Luis Filipe; Sicho, Petr

2017-01-01

The ATLAS Forward Proton (AFP) detector consists of two forward detectors located at 205 m and 217 m on either side of the ATLAS experiment. The aim is to measure the momenta and angles of diffractively scattered protons. In 2016, two detector stations on one side of the ATLAS interaction point were installed and commissioned. The detector infrastructure and necessary services were installed and are supervised by the Detector Control System (DCS), which is responsible for the coherent and safe operation of the detector. A large variety of used equipment represents a considerable challenge for the AFP DCS design. Industrial Supervisory Control and Data Acquisition (SCADA) product Siemens WinCCOA, together with the CERN Joint Control Project (JCOP) framework and standard industrial and custom developed server applications and protocols are used for reading, processing, monitoring and archiving of the detector parameters. Graphical user interfaces allow for overall detector operation and visualization of the det...

Strip detector for the ATLAS detector upgrade for the High-Luminosity LHC

CERN Document Server

Veloce, Laurelle Maria; The ATLAS collaboration

2017-01-01

The ATLAS experiment is currently preparing for an upgrade of the tracking system in the course of the High Luminosity LHC, scheduled for 2025. The expected radiation damage at an integrated luminosity of 3000fb-1 will require the tracking detectors to withstand hadron fluencies to over 1x1016 1 MeV neutron equivalent per cm2. With the addition of increased readout rates, the existing Inner Detector will have to be replaced by an all-silicon Inner Tracker (ITk) with a pixel detector surrounded by a strip detector. The ITk strip detector consists of a four-layer barrel and a forward region composed of six discs on each side of the barrel. The current prototyping phase has resulted in the ITk Strip Detector Technical Design Report (TDR), which starts the pre-production readiness phase at the involved institutes. In this contribution we present the design of the ITk Strip Detector and current status of R&D of various detector components.

Silicon radiation detectors

International Nuclear Information System (INIS)

Lutz, G.

1995-01-01

An introduction to and an overview of function principles and properties of semiconductor radiation detectors is attempted. The paper is addressed to people interested in detector development but not already experts in the field of semiconductor detectors. (orig.)

Towards a data and detector characterization robot for gravitational wave detectors

CERN Document Server

Mohanty, S D

2002-01-01

A change of non-astrophysical origin in the detector state or in the statistical nature of data while an interferometer is in lock reflects an abnormality. The change can manifest itself in many forms: transients, drifts in noise power spectral density, change in cross correlation between channels, etc. We advance the idea of an algorithm for detecting such change points whose design goal is reliable performance, i.e. a known false alarm rate, even when statistically unmodelled data such as those from the physical environmental monitors are included. Reliability is important since following up on such change points could be fairly labour intensive. Such an algorithm need not be simply a collection of isolated independent monitors running in parallel. We present the first design steps towards building this detector characterization robot along with some preliminary results and outline some possibilities for the future.

Smile detectors correlation

Science.gov (United States)

Yuksel, Kivanc; Chang, Xin; Skarbek, Władysław

2017-08-01

The novel smile recognition algorithm is presented based on extraction of 68 facial salient points (fp68) using the ensemble of regression trees. The smile detector exploits the Support Vector Machine linear model. It is trained with few hundreds exemplar images by SVM algorithm working in 136 dimensional space. It is shown by the strict statistical data analysis that such geometric detector strongly depends on the geometry of mouth opening area, measured by triangulation of outer lip contour. To this goal two Bayesian detectors were developed and compared with SVM detector. The first uses the mouth area in 2D image, while the second refers to the mouth area in 3D animated face model. The 3D modeling is based on Candide-3 model and it is performed in real time along with three smile detectors and statistics estimators. The mouth area/Bayesian detectors exhibit high correlation with fp68/SVM detector in a range [0:8; 1:0], depending mainly on light conditions and individual features with advantage of 3D technique, especially in hard light conditions.

Modeling Charge Collection in Detector Arrays

Science.gov (United States)

Hardage, Donna (Technical Monitor); Pickel, J. C.

2003-01-01

A detector array charge collection model has been developed for use as an engineering tool to aid in the design of optical sensor missions for operation in the space radiation environment. This model is an enhancement of the prototype array charge collection model that was developed for the Next Generation Space Telescope (NGST) program. The primary enhancements were accounting for drift-assisted diffusion by Monte Carlo modeling techniques and implementing the modeling approaches in a windows-based code. The modeling is concerned with integrated charge collection within discrete pixels in the focal plane array (FPA), with high fidelity spatial resolution. It is applicable to all detector geometries including monolithc charge coupled devices (CCDs), Active Pixel Sensors (APS) and hybrid FPA geometries based on a detector array bump-bonded to a readout integrated circuit (ROIC).

Flipping Undergraduate Finite Mathematics: Findings and Implications

Science.gov (United States)

Guerrero, Shannon; Beal, Melissa; Lamb, Chris; Sonderegger, Derek; Baumgartel, Drew

2015-01-01

This paper reports on a research project that investigated the effects of a flipped instructional approach on student attitudes and achievement in a lower division university-level Finite Mathematics course. The project employed a mixed-methods design that included content exams, an attitude survey, open-ended student responses, observations, and…

Pion-induced damage in silicon detectors

CERN Document Server

Bates, S; Glaser, M; Lemeilleur, F; León-Florián, E; Gössling, C; Kaiser, B; Rolf, A; Wunstorf, R; Feick, H; Fretwurst, E; Lindström, G; Moll, Michael; Taylor, G; Chilingarov, A G

1995-01-01

The damage induced by pions in silicon detectors is studied for positive and negative pions for fluence up to 10(14)cm-2 and 10(13) cm-2 respectively. Results on the energy dependence of the damage in the region of 65-330 MeV near to the  resonance are presented. The change in detector characteristics such as leakage current, charge collection efficiency and effective impurity concentration including long-term annealing effects have been studied. Comparisons to neutron and proton-induced damage are presented and discussed.

The solenoidal detector collaboration silicon detector system

International Nuclear Information System (INIS)

Ziock, H.J.; Gamble, M.T.; Miller, W.O.; Palounek, A.P.T.; Thompson, T.C.

1992-01-01

Silicon tracking systems (STS) will be fundamental components of the tracking systems for both planned major SSC experiments. The STS is physically a small part of the central tracking system and the calorimeter of the detector being proposed by the Solenoidal Detector Collaboration (SDC). Despite its seemingly small size, it occupies a volume of more than 5 meters in length and 1 meter in diameter and is an order of magnitude larger than any silicon detector system previously built. The STS will consist of silicon microstrip detectors and possibly silicon pixel detectors. The other two components are an outer barrel tracker, which will consist of straw tubes or scintillating fibers; and an outer intermediate angle tracker, which will consist of gas microstrips. The components are designed to work as an integrated system. Each componenet has specific strengths, but is individually incapable of providing the overall performance required by the physics goals of the SSC. The large particle fluxes, the short times between beam crossing, the high channel count, and the required very high position measurement accuracy pose challenging problems that must be solved. Furthermore, to avoid degrading the measurements, the solutions must be achieved using only a minimal amount of material. An additional constraint is that only low-Z materials are allowed. If that were not difficlut enough, the solutions must also be affordable

Verification of Orthogrid Finite Element Modeling Techniques

Science.gov (United States)

Steeve, B. E.

1996-01-01

The stress analysis of orthogrid structures, specifically with I-beam sections, is regularly performed using finite elements. Various modeling techniques are often used to simplify the modeling process but still adequately capture the actual hardware behavior. The accuracy of such 'Oshort cutso' is sometimes in question. This report compares three modeling techniques to actual test results from a loaded orthogrid panel. The finite element models include a beam, shell, and mixed beam and shell element model. Results show that the shell element model performs the best, but that the simpler beam and beam and shell element models provide reasonable to conservative results for a stress analysis. When deflection and stiffness is critical, it is important to capture the effect of the orthogrid nodes in the model.

The OSMOND detector

Energy Technology Data Exchange (ETDEWEB)

Bateman, J.E. [Technology Dept. Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX (United Kingdom); Dalgliesh, R. [ISIS Dept. Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX (United Kingdom); Duxbury, D.M., E-mail: dom.duxbury@stfc.ac.uk [Technology Dept. Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX (United Kingdom); Helsby, W.I. [Science and Technology Facilities Council, Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington WA4 4AD (United Kingdom); Holt, S.A.; Kinane, C.J. [ISIS Dept. Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX (United Kingdom); Marsh, A.S. [Diamond Light Source LTD, Harwell Science and Innovation Campus, Diamond House, Chilton, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Rhodes, N.J.; Schooneveld, E.M. [ISIS Dept. Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX (United Kingdom); Spill, E.J.; Stephenson, R. [Technology Dept. Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX (United Kingdom)

2013-01-11

The development and testing of the Off Specular MicrOstrip Neutron Detector (OSMOND) is described. Based on a microstrip gas chamber the aim of the project was to produce a high counting rate detector capable of replacing the existing rate limited scintillator detectors currently in use on the CRISP reflectometer for off specular reflectometry experiments. The detector system is described together with results of neutron beam tests carried out at the ISIS spallation neutron source.

One dimensional detector for X-ray diffraction with superior energy resolution based on silicon strip detector technology

International Nuclear Information System (INIS)

Dąbrowski, W; Fiutowski, T; Wiącek, P; Fink, J; Krane, H-G

2012-01-01

1-D position sensitive X-ray detectors based on silicon strip detector technology have become standard instruments in X-ray diffraction and are available from several vendors. As these devices have been proven to be very useful and efficient further improvement of their performance is investigated. The silicon strip detectors in X-ray diffraction are primarily used as counting devices and the requirements concerning the spatial resolution, dynamic range and count rate capability are of primary importance. However, there are several experimental issues in which a good energy resolution is important. The energy resolution of silicon strip detectors is limited by the charge sharing effects in the sensor as well as by noise of the front-end electronics. The charge sharing effects in the sensor and various aspects of the electronics, including the baseline fluctuations, which affect the energy resolution, have been analyzed in detail and a new readout concept has been developed. A front-end ASIC with a novel scheme of baseline restoration and novel interstrip logic circuitry has been designed. The interstrip logic is used to reject the events resulting in significant charge sharing between neighboring strips. At the expense of rejecting small fraction of photons entering the detector one can obtain single strip energy spectra almost free of charge sharing effects. In the paper we present the design considerations and measured performance of the detector being developed. The electronic noise of the system at room temperature is typically of the order of 70 el rms for 17 mm long silicon strips and a peaking time of about 1 μs. The energy resolution of 600 eV FWHM has been achieved including the non-reducible charge sharing effects and the electronic noise. This energy resolution is sufficient to address a common problem in X-ray diffraction, i.e. electronic suppression of the fluorescence radiation from samples containing iron or cobalt while irradiated with 8.04 ke

Recent advances in self-powered flux detector development for CANDU reactors

International Nuclear Information System (INIS)

Allan, C.J.; Drewell, N.H.; Hall, D.S.

1983-01-01

The characteristics of self-powered flux detectors used in CANDU reactors are reviewed. Detectors with emitters of vanadium, platinum, platinum-clad Inconel and Inconel are used. Data on dynamic response, relative neutron and gamma-ray sensitivities, and burnout, obtained both from experiments and from the Monte Carlo code ICARES, are presented. Since the response of a detector depends on the relative magnitudes of the various current-producing mechanisms, the operating principles of self-powered detectors are briefly reviewed. Current research programmes are discussed. These include modifying the design of the platinum-clad Inconel detector in order to match its dynamic response to that of the fuel power and developing a prompt-responding flux-mapping detector. (author)

Virtual point detector: On the interpolation and extrapolation of scintillation detectors counting efficiencies

International Nuclear Information System (INIS)

Presler, Oren; German, Uzi; Pushkarsky, Vitaly; Alfassi, Zeev B.

2006-01-01

The concept of transforming the detector volume to a virtual point detector, in order to facilitate efficiency evaluations for different source locations, was proposed in the past for HPGe and Ge(Li) detectors. The validity of this model for NaI(Tl) and BGO scintillation detectors was studied in the present work. It was found that for both scintillation detectors, the point detector model does not seem to fit too well to the experimental data, for the whole range of source-to-detector distances; however, for source-to-detector cap distances larger than 4 cm, the accuracy was found to be high. A two-parameter polynomial expression describing the dependence of the normalized count rate versus the source-to-detector distance was fitted to the experimental data. For this fit, the maximum deviations are up to about 12%. These deviations are much smaller than the values obtained by applying the virtual point concept, even for distances greater than 4 cm, thus the polynomial fitting is to be preferred for scintillation detectors

Novel Front-end Electronics for Time Projection Chamber Detectors

CERN Document Server

García García, Eduardo José

This work has been carried out in the European Organization for Nuclear Research (CERN) and it was supported by the European Union as part of the research and development towards the European detector the (EUDET) project, specifically for the International Linear Collider (ILC). In particle physics there are several different categories of particle detectors. The presented design is focused on a particular kind of tracking detector called Time Projection Chamber (TPC). The TPC provides a three dimensional image of electrically charged particles crossing a gaseous volume. The thesis includes a study of the requirements for future TPC detectors summarizing the parameters that the front-end readout electronics must fulfill. In addition, these requirements are compared with respect to the readouts used in existing TPC detectors. It is concluded that none of the existing front-end readout designs fulfill the stringent requirements. The main requirements for future TPC detectors are high integration, an increased n...

Detector trends

International Nuclear Information System (INIS)

Charpak, G.

1986-01-01

The author describes briefly the development of detectors for high energy physics experiments. Especially considered are semiconductor microstrip detectors, drift tubes, holographic bubble chambers, scintillating fiber optics, and calorimeters. (HSI).

Dual concentric crystal low energy photon detector

Science.gov (United States)

Guilmette, R.A.

A photon detector for biological samples includes a block of NaI(T1) having a hole containing a thin walled cylinder of CsI(T1). At least three photo multiplier tubes are evenly spaced around the parameter of the block. Biological samples are placed within the hole, and emissions which are sensed by at least two of the photo multipliers from only the NaI(T1) detector are counted.

Nonlinear Legendre Spectral Finite Elements for Wind Turbine Blade Dynamics: Preprint

Energy Technology Data Exchange (ETDEWEB)

Wang, Q.; Sprague, M. A.; Jonkman, J.; Johnson, N.

2014-01-01

This paper presents a numerical implementation and examination of new wind turbine blade finite element model based on Geometrically Exact Beam Theory (GEBT) and a high-order spectral finite element method. The displacement-based GEBT is presented, which includes the coupling effects that exist in composite structures and geometric nonlinearity. Legendre spectral finite elements (LSFEs) are high-order finite elements with nodes located at the Gauss-Legendre-Lobatto points. LSFEs can be an order of magnitude more efficient that low-order finite elements for a given accuracy level. Interpolation of the three-dimensional rotation, a major technical barrier in large-deformation simulation, is discussed in the context of LSFEs. It is shown, by numerical example, that the high-order LSFEs, where weak forms are evaluated with nodal quadrature, do not suffer from a drawback that exists in low-order finite elements where the tangent-stiffness matrix is calculated at the Gauss points. Finally, the new LSFE code is implemented in the new FAST Modularization Framework for dynamic simulation of highly flexible composite-material wind turbine blades. The framework allows for fully interactive simulations of turbine blades in operating conditions. Numerical examples showing validation and LSFE performance will be provided in the final paper.

DETECTORS: Vienna - beyond the wire

International Nuclear Information System (INIS)

Krammer, Manfred; Regler, Meinhard

1995-01-01

presentations. Both ATLAS and CMS demonstrated different approaches to mastering the difficulties of covering large areas with precise detectors capable of resolving consecutive bunches. Proposed techniques included thin gap chambers, straw drift tubes, pressurized drift tubes, resistive plate chambers...

Monte Carlo simulated corrections for beam commissioning measurements with circular and MLC shaped fields on the CyberKnife M6 System: a study including diode, microchamber, point scintillator, and synthetic microdiamond detectors

Science.gov (United States)

Francescon, P.; Kilby, W.; Noll, J. M.; Masi, L.; Satariano, N.; Russo, S.

2017-02-01

Monte Carlo simulation was used to calculate correction factors for output factor (OF), percentage depth-dose (PDD), and off-axis ratio (OAR) measurements with the CyberKnife M6 System. These include the first such data for the InCise MLC. Simulated detectors include diodes, air-filled microchambers, a synthetic microdiamond detector, and point scintillator. Individual perturbation factors were also evaluated. OF corrections show similar trends to previous studies. With a 5 mm fixed collimator the diode correction to convert a measured OF to the corresponding point dose ratio varies between  -6.1% and  -3.5% for the diode models evaluated, while in a 7.6 mm  ×  7.7 mm MLC field these are  -4.5% to  -1.8%. The corresponding microchamber corrections are  +9.9% to  +10.7% and  +3.5% to  +4.0%. The microdiamond corrections have a maximum of  -1.4% for the 7.5 mm and 10 mm collimators. The scintillator corrections are  15%, reducing to    d max were  M6 Systems and retrospectively checking estimated corrections used previously. We recommend the PDD and OAR corrections are used to guide detector selection and inform the evaluation of results rather than to explicitly correct measurements.

Design and performance of a cesium iodide detector

Energy Technology Data Exchange (ETDEWEB)

Adams, T.; Bishop, J.M.; Cady, R. [Notre Dame Univ., IN (United States)] [and others

1996-01-11

The design, construction, and performance of a 198-element CsI detector built for Brookhaven experiment E852 is described. Design considerations for the array included such factors as rate, magnetic field, sensitivity and acceptance. Signals were obtained with a photodiode/preamplifier combination using PIN photodiodes. Data were taken over the course of two runs during the summers of 1993 and 1994. A calibration procedure using halo muons is described. The gain, energy resolution, and position resolution of the detector are discussed. Finally, the ability of the detector to be used as a low energy photon veto is illustrated using the data. (orig.).

Relativistic finite-temperature Thomas-Fermi model

Science.gov (United States)

Faussurier, Gérald

2017-11-01

We investigate the relativistic finite-temperature Thomas-Fermi model, which has been proposed recently in an astrophysical context. Assuming a constant distribution of protons inside the nucleus of finite size avoids severe divergence of the electron density with respect to a point-like nucleus. A formula for the nuclear radius is chosen to treat any element. The relativistic finite-temperature Thomas-Fermi model matches the two asymptotic regimes, i.e., the non-relativistic and the ultra-relativistic finite-temperature Thomas-Fermi models. The equation of state is considered in detail. For each version of the finite-temperature Thomas-Fermi model, the pressure, the kinetic energy, and the entropy are calculated. The internal energy and free energy are also considered. The thermodynamic consistency of the three models is considered by working from the free energy. The virial question is also studied in the three cases as well as the relationship with the density functional theory. The relativistic finite-temperature Thomas-Fermi model is far more involved than the non-relativistic and ultra-relativistic finite-temperature Thomas-Fermi models that are very close to each other from a mathematical point of view.

Electromagnetic radiation detector

Science.gov (United States)

Benson, Jay L.; Hansen, Gordon J.

1976-01-01

An electromagnetic radiation detector including a collimating window, a cathode member having a photoelectric emissive material surface angularly disposed to said window whereby radiation is impinged thereon at acute angles, an anode, separated from the cathode member by an evacuated space, for collecting photoelectrons emitted from the emissive cathode surface, and a negatively biased, high transmissive grid disposed between the cathode member and anode.

Geometrically Unfitted Finite Element Methods and Applications : Proceedings of the UCL Workshop 2016

CERN Document Server

Burman, Erik; Larson, Mats; Olshanskii, Maxim

2017-01-01

This book provides a snapshot of the state of the art of the rapidly evolving field of integration of geometric data in finite element computations. The contributions to this volume, based on research presented at the UCL workshop on the topic in January 2016, include three review papers on core topics such as fictitious domain methods for elasticity, trace finite element methods for partial differential equations defined on surfaces, and Nitsche’s method for contact problems. Five chapters present original research articles on related theoretical topics, including Lagrange multiplier methods, interface problems, bulk-surface coupling, and approximation of partial differential equations on moving domains. Finally, two chapters discuss advanced applications such as crack propagation or flow in fractured poroelastic media. This is the first volume that provides a comprehensive overview of the field of unfitted finite element methods, including recent techniques such as cutFEM, traceFEM, ghost penalty, and aug...

Finite element model for heat conduction in jointed rock masses

International Nuclear Information System (INIS)

Gartling, D.K.; Thomas, R.K.

1981-01-01

A computatonal procedure for simulating heat conduction in a fractured rock mass is proposed and illustrated in the present paper. The method makes use of a simple local model for conduction in the vicinity of a single open fracture. The distributions of fractures and fracture properties within the finite element model are based on a statistical representation of geologic field data. Fracture behavior is included in the finite element computation by locating local, discrete fractures at the element integration points

DEPFET-detectors: New developments

Energy Technology Data Exchange (ETDEWEB)

Lutz, G. [MPI Semiconductor Laboratory, Max Planck Institut fuer Physik, Otto Hahn Ring 6, D 81739 Munich (Germany)]. E-mail: gerhard.lutz@cern.ch; Andricek, L. [MPI Semiconductor Laboratory, Max Planck Institut fuer Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Eckardt, R. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Haelker, O. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Hermann, S. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Lechner, P. [MPI Semiconductor Laboratory, PNSensor GmbH, Otto Hahn Ring 6, D 81739 Munich (Germany); Richter, R. [MPI Semiconductor Laboratory, Max Planck Institut fuer Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Schaller, G. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Schopper, F. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Soltau, H. [MPI Semiconductor Laboratory, PNSensor GmbH, Otto Hahn Ring 6, D 81739 Munich (Germany); Strueder, L. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Treis, J. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Woelfl, S. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Zhang, C. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany)

2007-03-01

The Depleted Field Effect Transistor (DEPFET) detector-amplifier structure forms the basis of a variety of detectors being developed at the MPI semiconductor laboratory. These detectors are foreseen to be used in astronomy and particle physics as well as other fields of science. The detector developments are described together with some intended applications. They comprise the X-ray astronomy missions XEUS and SIMBOL-X as well as the vertex detector of the planned International Linear Collider (ILC). All detectors are produced in the MPI semiconductor laboratory that has a complete silicon technology available.

DEPFET-detectors: New developments

International Nuclear Information System (INIS)

Lutz, G.; Andricek, L.; Eckardt, R.; Haelker, O.; Hermann, S.; Lechner, P.; Richter, R.; Schaller, G.; Schopper, F.; Soltau, H.; Strueder, L.; Treis, J.; Woelfl, S.; Zhang, C.

2007-01-01

The Depleted Field Effect Transistor (DEPFET) detector-amplifier structure forms the basis of a variety of detectors being developed at the MPI semiconductor laboratory. These detectors are foreseen to be used in astronomy and particle physics as well as other fields of science. The detector developments are described together with some intended applications. They comprise the X-ray astronomy missions XEUS and SIMBOL-X as well as the vertex detector of the planned International Linear Collider (ILC). All detectors are produced in the MPI semiconductor laboratory that has a complete silicon technology available

Finite time thermodynamics of power and refrigeration cycles

CERN Document Server

Kaushik, Shubhash C; Kumar, Pramod

2017-01-01

This book addresses the concept and applications of Finite Time Thermodynamics to various thermal energy conversion systems including heat engines, heat pumps, and refrigeration and air-conditioning systems. The book is the first of its kind, presenting detailed analytical formulations for the design and optimisation of various power producing and cooling cycles including but not limited to: • Vapour power cycles • Gas power cycles • Vapour compression cycles • Vapour absorption cycles • Rankine cycle coupled refrigeration systems Further, the book addresses the thermoeconomic analysis for the optimisation of thermal cycles, an important field of study in the present age and which is characterised by multi-objective optimization regarding energy, ecology, the environment and economics. Lastly, the book provides the readers with key techniques associated with Finite Time Thermodynamics, allowing them to understand the relevance of irreversibilitie s associated with real processes and the scientific r...

An analysis of the control hierarchy modelling of the CMS detector control system

Energy Technology Data Exchange (ETDEWEB)

Hwong, Yi-Ling; et al.

2011-01-01

The supervisory level of the Detector Control System (DCS) of the CMS experiment is implemented using Finite State Machines (FSM), which model the behaviours and control the operations of all the sub-detectors and support services. The FSM tree of the whole CMS experiment consists of more than 30.000 nodes. An analysis of a system of such size is a complex task but is a crucial step towards the improvement of the overall performance of the FSM system. This paper presents the analysis of the CMS FSM system using the micro Common Representation Language 2 (mcrl2) methodology. Individual mCRL2 models are obtained for the FSM systems of the CMS sub-detectors using the ASF+SDF automated translation tool. Different mCRL2 operations are applied to the mCRL2 models. A mCRL2 simulation tool is used to closer examine the system. Visualization of a system based on the exploration of its state space is enabled with a mCRL2 tool. Requirements such as command and state propagation are expressed using modal mu-calculus and checked using a model checking algorithm. For checking local requirements such as endless loop freedom, the Bounded Model Checking technique is applied. This paper discusses these analysis techniques and presents the results of their application on the CMS FSM system.

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Keil, M; The ATLAS collaboration

2012-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC and its status after three years of operation will be presented, including calibration procedures, timing optimization and detector performance. The detector performance is excellent: ~96 % of the pixels are operational, noise occupancy and hit efficiency e...

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Keil, M; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Hirschbuehl, D; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.7% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Lapoire, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Lapoire, C; The ATLAS collaboration

2012-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as B-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification.

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Keil, M

2012-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper results from the successful operation of the Pixel Detector at the LHC will be presented, including calibration procedures, timing optimization and detector performance. The detector performance is excellent: approximately 97% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Ince, T; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.8% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel detector at the LHC

CERN Document Server

Deluca, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5\\% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, ...

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Lange, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump- bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, a...

Operational experience with the ATLAS Pixel detector at the LHC

CERN Document Server

Deluca, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Supersymmetric theories and finiteness

International Nuclear Information System (INIS)

Helayel-Neto, J.A.

1989-01-01

We attempt here to present a short survey of the all-order finite Lagrangian field theories known at present in four-and two-dimensional space-times. The question of the possible relevance of these ultraviolet finite models in the formulation of consistent unified frameworks for the fundamental forces is also addressed to. (author)

Position-sensitive superconductor detectors

International Nuclear Information System (INIS)

Kurakado, M.; Taniguchi, K.

2016-01-01

Superconducting tunnel junction (STJ) detectors and superconducting transition- edge sensors (TESs) are representative superconductor detectors having energy resolutions much higher than those of semiconductor detectors. STJ detectors are thin, thereby making it suitable for detecting low-energy X rays. The signals of STJ detectors are more than 100 times faster than those of TESs. By contrast, TESs are microcalorimeters that measure the radiation energy from the change in the temperature. Therefore, signals are slow and their time constants are typically several hundreds of μs. However, TESs possess excellent energy resolutions. For example, TESs have a resolution of 1.6 eV for 5.9-keV X rays. An array of STJs or TESs can be used as a pixel detector. Superconducting series-junction detectors (SSJDs) comprise multiple STJs and a single-crystal substrate that acts as a radiation absorber. SSJDs are also position sensitive, and their energy resolutions are higher than those of semiconductor detectors. In this paper, we give an overview of position-sensitive superconductor detectors.

A Polyethylene Moderator Design for Auxiliary Ex-core Neutron Detector

International Nuclear Information System (INIS)

Lee, Hwan Soo; Shin, Ho Cheol; Bae, Seong Man

2012-01-01

The moderator of detector assembly in ENFMS (Excore Neutron Flux Monitoring System) plays a key role for slowing down from fast neutron to thermal neutron at outside of reactor vessel. Since neutron monitoring detector such as BF3, fission chamber detectors mostly responds to thermal neutron, moderator should be included to neutron detector assembly to detect more efficiently. Generally, resin has been used for moderator of detector in ENFMS of OPR1000 and APR1400, because resin has stable thermal resistance, availability and high neutron moderation characteristics due to the light atomic materials. In case of an auxiliary ex-core neutron detector, the polyethylene is suggested that polyethylene has a better moderator rather than resin, then, the amounts of moderator are reduced. This is important thing for auxiliary ex-core detector equipment at reactor, because the auxiliary equipment should affect minimally to another system. In this study, polyethylene moderator is designed for auxiliary ex-core neutron detector. To find out the optimal thickness of polyethylene moderator, preliminary simulation and experiments are performed. And sensitivity simulation for detector moderator at actual reactor is performed by DORT code

Superconducting Detectors for Superlight Dark Matter.

Science.gov (United States)

Hochberg, Yonit; Zhao, Yue; Zurek, Kathryn M

2016-01-08

We propose and study a new class of superconducting detectors that are sensitive to O(meV) electron recoils from dark matter-electron scattering. Such devices could detect dark matter as light as the warm dark-matter limit, m(X)≳1  keV. We compute the rate of dark-matter scattering off of free electrons in a (superconducting) metal, including the relevant Pauli blocking factors. We demonstrate that classes of dark matter consistent with terrestrial and cosmological or astrophysical constraints could be detected by such detectors with a moderate size exposure.

A first course in finite elements

CERN Document Server

Fish, Jacob

2007-01-01

Developed from the authors, combined total of 50 years undergraduate and graduate teaching experience, this book presents the finite element method formulated as a general-purpose numerical procedure for solving engineering problems governed by partial differential equations.  Focusing on the formulation and application of the finite element method through the integration of finite element theory, code development, and software application, the book is both introductory and self-contained, as well as being a hands-on experience for any student. This authoritative text on Finite Elements:Adopts

Features of finite quantum field theories