Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “SIGNAL CONDITIONERS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Design of a signal conditioner for the Fermilab Magnet Test Facility

This thesis describes the design of a remotely-programmable signal conditioner for the harmonic measurement of accelerator magnets. A 10-channel signal conditioning circuit featuring bucking capabilities was designed from scratch and implemented to the level of the printed circuit board layout. Other system components were chosen from those available on the market. Software design was started with the definition of routine procedures. This thesis is part of an upgrade project for replacing obsolescent automated test equipment belonging to the Fermilab Magnet Test Facility. The design started with a given set of requirements. Using a top-down approach, all the circuits were designed and their expected performances were theoretically predicted and simulated. A limited prototyping phase followed. The printed circuit boards were laid out and routed using a CAD software and focusing the design on maximum electromagnetic interference immunity. An embedded board was selected for controlling and interfacing the signal conditioning circuitry with the instrumentation network. Basic low level routines for hardware access were defined. This work covered the entire design process of the signal conditioner, resulting in a project ready for manufacturing. The expected performances are in line with the requirements and, in the cases where this was not possible, approval of trade-offs was sought and received from the end users. Part I deals with the global structure of the signal conditioner and the subdivision in functional macro-blocks. Part II treats the hardware design phase in detail, covering the analog and digital circuits, the printed circuit layouts, the embedded controller and the power supply selection. Part III deals with the basic hardware-related routines to be implemented in the final software.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

NBSR reactor control room upgrade - 215

The maintenance and modernization of the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) reactor, known as the NBSR, is an ongoing process to endure until the eventual decommissioning of the reactor. As part of the renovation effort, the reactor control system is to be upgraded. Following some initial outsourcing efforts, the NBSR reactor control system upgrade has been restructured to be implemented by in-house means. The beginning stage of the upgrade involved the development of a simulator environment based on a PC system and digitization of the majority of nuclear reactor monitoring data. The NBSR reactor surveillance data consists of approximately thirteen hundred input/output points, including analog/digital sensor signals, signal conditioners, and relay logic. The aim of the current phase is to implement a new reactor data acquisition and display system (RDS) and lay out the infrastructure for the upgrade of the reactor control system (RCS). Key design criteria are to implement a reliable, redundant, diverse, modular and candid system where any complex digital manipulations are taken outside of the control room. Basically, the data analytics and custom codes are separated from reactor operation control and decision making logic. Furthermore, the new RDS is designed such that it could be maintained internally by NCNR personnel. The RDS is unique in design and modularity, minimizing custom codes and testing, making it ideal for research reactors. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2014

A Model-Based Approach to Scintillator/Photomultiplier System Characterization

Scintillator/photomultiplier systems are prevalent in many instruments to measure a variety on nuclear events. When gamma energy from a nuclear event irradiates the scintillator, event radiation interacts with the scintillator material generating photons which are detected by the photomultiplier tube (PMT). The PMT photoelectrons or photocathode current is amplified in the PMT by a number of dynode stages producing a total charge out for a given radiation flux into scintillator. The resulting current is converted to a voltage when passed through a typical load impedance. This voltage is attenuated and provided as input to a digitizer through a variety of signal conditioners (filters, amplifiers, receivers) before analog-to-digital conversion. In this report, we concentrate on the development of analytic models for the scintillator/photomultiplier system and develop both a (1) statistical simulator; and (2) a model-based signal processor to extract the desired signal information while rejecting the noise and uncertainty. We develop the model analytically, transform it to the model-based framework (state-space), and then use actual experimental data to fit the model and apply it to our processing problem.

42 ENGINEERING↗
DOE OSTI2010

Front-end Electronics for the ALICE Calorimeters

The ALICE calorimeters PHOS and EMCal are based on Avalanche Photo-Diode (APD) photosensors with Charge Sensitive Preamplifiers (CSP) for readout of the scintillating elements. The amplified signals are read out via 32-channel shaper/digitizer front-end electronics (FEE) with 14-bit effective dynamic range. The electronics is based on second order shapers with dual gain for each channel, getting digitized by ALTRO chips. Each APD channel is equipped with an individual 10-bit APD gain adjustment and 2 x 2 channel clusters generate a 100 ns shaped analog sums output (Fast OR) for the associated Trigger Region Units (TRU). The Fast OR signals are generated by first order shapers with a dynamic range of 12-bit given by the ADC in the TRU cards. Board controller firmware in the FPGA provides local monitoring and configuration of all parameters via the ALICE DCS system. The signal to noise ratio for MIP at 215 MeV is {approx}7 per channel with a noise level of 30 MeV at room temperature for a dynamic range of 80 GeV for PHOS, and the fast-OR RMS noise level is about 75 MeV for a dynamic range of 250 GeV for EMCal.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

Compton Imaging Capabilities of AGATA for Background Rejection

In this work we present the results of the test performed at the Laboratori Nazionali di Legnaro (LNL) aiming to characterize the capabilities of the AGATA detectors to discriminate between different gamma source locations. AGATA detectors are position sensitive to the interaction points through Pulse Shape Analysis allowing location of the gamma sources by using Compton imaging algorithm. The final goal is to increase the array sensitivity reducing the background originated outside the AGATA target.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

LCP Identification Method based on Pulse Shape Analysis

An improved LCP identification method based on Pulse shape analyses has been designed, the module 'Dual Pulse-Shape Analyzer' has been built and tested and resent experimental results of instrument utilizing have been presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

Digital Pulse Processing: A New Paradigm For Nuclear Instrumentation

In recent years, we have seen an impressive increase in the use of digital pulse processing in substitution of standard analog electronic modules for nuclear physics instrumentation. The main advantages of the new standard are compactness, no additional noise after digitization of the pre-amp signal, reliability (no cables and connectors), and possibility of easily reproducing the same tuning set up. Also, it opens new possibilities of pulse shape analysis, not possible with standard analog electronics.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

Bunch characteristics of an electron beam generated by a diamond secondary emitter amplifier

Electron bunches for high performance free electron lasers are subject to constraints on charge per bunch and pulse shape. A Diamond secondary emitter used in conjunction with a photocathode and drive laser has potential to enable a high brightness, high peak current photoinjector by increasing the effective quantum efficiency of the photocathode. A theoretical characterization of the bunches so produced has been heretofore absent. Using a combination of Monte Carlo and analytical models, the shape of the bunches, their transit time, and emission time constants are determined and shown to be sensitive to the accelerating field in the diamond flake, incident beam profile, doping, and surface conditions. Methods to allow for extension to regimes of technological interest in terms of diamond thickness, external field, and primary pulse shape are given.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2010

An analytical model for pulse shape and electrothermal stability in two-body transition-edge sensor microcalorimeters

High-resolution superconducting gamma-ray sensors show potential for the more accurate analysis of nuclear material. These devices are part of a larger class of microcalorimeters and bolometers based on transition edge sensors (TESs) that have two distinct thermal bodies. We derive the time domain behavior of the current and temperature for compound TES devices in the small signal limit and demonstrate the utility of these equations for device design and characterization. In particular, we use the model to fit pulses from our gamma-ray microcalorimeters and demonstrate how critical damping and electrothermal stability can be predicted.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

A New Method of Prompt Fission Neutron Energy Spectrum Unfolding

The prompt neutron emission in spontaneous fission of {sup 252}Cf has been investigated applying digital signal electronics along with associated digital signal processing algorithms. The goal was to find out the reasons of a long time existing discrepancy between theoretical calculations and the measurements of prompt fission neutron (PFN) emission dependence on the total kinetic energy (TKE) of fission fragments (FF). On the one hand the {sup 252}Cf(sf) reaction is one of the main references for nuclear data, on the other hand the understanding of PFN emission mechanism is very important for nuclear fission theory. Using a twin Frisch-grid ionization chamber for fission fragment (FF) detection and a NE213-equivalent neutron detector in total about 10{sup 7} fission fragment-neutron coincidences have been registered. Fission fragment kinetic energy, mass and angular distribution, neutron time-of-flight and pulse shape have been investigated using a 12 bit waveform digitizer. The signal waveforms have been analyzed using digital signal processing algorithms. For the first time the dependence of the number of emitted neutrons as a function of total kinetic energy (TKE) of the fragments is in very good agreement with theoretical calculations in the range of TKE from 140-220 MeV.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2010

Generation of Stable (3+1)-dimensional High-intensity Ultrashort Light Pulses

The spatiotemporal dynamics of high-intensity femtosecond laser pulses is studied within a rigorous physical model. The pulse propagation is described by the nonlinear envelope equation. The propagation and the material equations are solved self-consistently at realistic physical conditions. Self-compression of the pulse around single-cycle regime and dramatic increase of the pulse intensity is found. At certain conditions, the peak intensity, transversal width, time duration, and the spatiotemporal pulse shape remain stable with the propagation of the pulse, resembling a soliton formation process. This, to our knowledge, is the first simulation of high-intensity ultrashort soliton formation dynamics in the (3+1)-dimensional case.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Fine tuning of phase qubit parameters for optimization of fast single-pulse readout

We analyze a two-level quantum system, describing the phase qubit, during a single-pulse readout process by a numerical solution of the time-dependent Schroedinger equation. It has been demonstrated that the readout error has a minimum for certain values of the system's basic parameters. In particular, the optimization of the qubit capacitance and the readout pulse shape leads to significant reduction in the readout error. It is shown that in an ideal case the fidelity can be increased to almost 97% for 2 ns pulse duration and to 96% for 1 ns pulse duration.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Measurement Of The Neutron Spectrum Of A DD Electronic Neutron Generator

A Cuttler-Shalev (C-S){sup 3}He proportional counter has been used to measure the energy spectrum of neutrons from a portable deuterium-deuterium electronic neutron generator. To improve the analysis of results from the C-S detector digital pulse shape analysis techniques have been used to eliminate neutron recoil artifacts in the recorded data. Data was collected using a 8-GHz, 10-bit waveform digitizer with its full scale corresponding to approximately 6-MeV neutrons. The measurements were made with the detector axis perpendicular to the direction of ions in the ENG in a plane 0.5-m to the side of the ENG, measuring neutrons emitted at an angle from 87.3 deg. to 92.7 deg. with respect to the path of ions in the ENG. The system demonstrated an energy resolution of approximately 0.040 MeV for the thermal peak and approximately 0.13 MeV at the DD neutron energy. In order to achieve the ultimate resolution capable with this type of detector it is clear that a higher-precision digitizer will be needed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Multi-Channel Integrated Circuits For Use In Research With Radioactive Ion Beams

The Integrated Circuits Design Research Laboratory at Southern Illinois University Edwardsville (SIUE) has been collaborating over the past several years with the Nuclear Reactions Group at Washington University (WU) on the development of a family of custom, multi-channel Integrated Circuits (ICs). To date, the collaboration has successfully produced two micro-chips. The first was an analog shaped and peak sensing chip known as HINP16C (Heavy Ion Nuclear Physics--16 Channel). The second chip, christened PSD8C (Pulse Shape Discrimination--8 Channel), was designed to logically complement (in terms of detector types) the HINP16C chip. The HINP16C chip, for use with solid-state detectors, produces sparsified analog pulse trains for both linear (pulse height) and timing (relative to an external reference) signals. A shaper and peak detector are implemented in the linear branch, and a pseudo Constant-Fraction Discriminator (CFD) and Time-to-Voltage Converter (TVC) are implemented in the logic/timing branch. The internal and external gain options make the chip suitable for use in a wide variety of applications. PSD8C greatly simplifies the pulse-processing electronics needed for large arrays of scintillation detectors. As the PSD8C employs user-controlled, multi-region charge integration, particle identification is inherent in the design. Each of the three pulse-height sub-channels consists of a gated integrator with eight programmable charging rates and an externally programmable gate generator that defines the start (with 4 time ranges) and the width (with 4 time ranges) of the gate, relative to an external discriminator signal. Moreover, each channel on the chip also contains a TVC. This paper describes the design, capabilities, and features of the HINP16C and PSD8C ICs along with a description of how the chips are being used. It also discusses modifications and enhancements which have been made to both chips and their associated prototypical systems in order to improve ease of use and increase performance.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Nuclear Fission Investigation with Twin Ionization Chamber

The purpose of the present paper was to report the recent results, obtained in development of digital pulse processing mathematics for prompt fission neutron (PFN) investigation using twin ionization chamber (TIC) along with fast neutron time-of-flight detector (ND). Due to well known ambiguities in literature (see refs. [4, 6, 9 and 11]), concerning a pulse induction on TIC electrodes by FF ionization, we first presented detailed mathematical analysis of fission fragment (FF) signal formation on TIC anode. The analysis was done using Ramo-Shockley theorem, which gives relation between charged particle motion between TIC electrodes and so called weighting potential. Weighting potential was calculated by direct numerical solution of Laplace equation (neglecting space charge) for the TIC geometry and ionization, caused by FF. Formulae for grid inefficiency (GI) correction and digital pulse processing algorithms for PFN time-of-flight measurements and pulse shape analysis are presented and discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

Laser-induced modification of transparent crystals and glasses

We analyse the processes taking place in transparent crystals and glasses irradiated by ultrashort laser pulses in the regimes typical of various applications in optoelectronics and photonics. We consider some phenomena, which have been previously described by the authors within the different model representations: charging of the dielectric surface due to electron photoemission resulting in a Coulomb explosion; crater shaping by using an adaptive control of the laser pulse shape; optimisation of the waveguide writing in materials strongly resistant to laser-induced compaction under ordinary irradiation conditions. The developed models and analysis of the processes relying on these models include the elements of the solid-state physics, plasma physics, thermodynamics, theory of elasticity and plasticity. Some important experimental observations which require explanations and adequate description are summarised. (photonics and nanotechnology)

36 MATERIALS SCIENCE↗
DOE OSTI2011

Determining the parameters of the laser radiation intensity limiter based on a time-dependent equation of radiative transfer in a nonlinear medium

The effect of the radiation intensity limitation is described using the time-dependent radiative transfer equation taking into account the nonlinearity of the working material of the limiter, which makes it possible to abstract from specific microscopic mechanisms of interaction of radiation with matter. An expression is presented which describes both the deformation of the shape of the laser pulse propagating through a nonlinear medium and the output characteristic (dependence of the output energy on the energy of incident radiation) of the limiter at a known dependence of the absorption coefficient on the laser pulsed radiation intensity with a given pulse shape. A functional equation is derived to determine the dependence of the absorption coefficient on the intensity from the experimental output characteristic, which allows one to predict the limiter properties for different thicknesses of the working medium, as well as to effectively compare limiters of different types. (nonlinear optical phenomena)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗