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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Threat Sources for Creating Synthetic Urban Search Data

Equivalent point source energy emission distributions were computed for various threat sources for use in simulating the detector responses for urban search scenarios. The sources include standard isotopic sources used in detector testing, medical and industrial sources occasionally encountered in urban searches, and several types of special nuclear materials. Most of the equivalent point source distributions represent small sources inside some amount of shielding, but the special nuclear material sources represent volumetrically distributed sources in spheres of metal. Text-based inputs for emission distributions are available for the Monte Carlo transport codes Monte Carlo N-Particle, SCALE/MAVRIC, and Omnibus/Shift, any of which can easily be converted to other formats. These sources were developed for use in the Radiological Anomaly Detection and Identification (RADAI) project and the follow-on project, the RADAI-Extended project, sponsored by the National Nuclear Security Administration Office of Defense Nuclear Nonproliferation Research and Development.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Machine Learning for DUNE Supernova Trigger

One of the major scientific goals of the Deep Underground Neutrino Experiment (DUNE) is to detect and measure the neutrino flux from galactic core-collapse supernovae. These neutrinos, which exist in the low energy range of up to a few tens of MeV and are responsible for carrying away over 99% of the gravitational binding energy of the supernova, provide an opportunity to study the end of life evolution of massive stars, as well as unique properties and interactions of neutrinos. Because galactic supernovae are expected to occur only on the timespan of every few decades, it is crucial that DUNE is able to detect supernova neutrino interactions when they occur. However, detecting these supernova interactions requires sifting through a large amount of data, and DUNE detectors require a trigger to signal when supernova neutrino events occur. Machine learning provides a potential approach to creating this trigger. This project generates ADC and ground truth images of neutrino interactions in a LArTPC detector as simulated by the Model of Argon Reaction Low Energy Yields (MARLEY) to be used for machine learning. The eventual goal of this work is to facilitate DUNE s detection of supernova neutrino interactions by building a machine learning pipeline that will train the trigger algorithm.

Damish, Stephanie↗
DOE OSTI2024

Secondary Emission Detector Modules for High Energy Physics Experiments

The objectives of this Phase I SBIR project and the corresponding work plan consisted of detector geometry simulations and functional studies of pre-prototypes for both venetian-blind type and MEMS type. Modifications and improvements to the vacuum test station and data acquisition were also made throughout the project. In the final stages of this Phase I, we were able to do initial testing of devices built and we provide in this report the results of these measurements and all corresponding conclusions.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Light Output Fitting Software

Light output response of scintillators is crucial to the utilization of organic scintillators as effective tools in radiation detection and measurement. While the response is a continuous distribution, the light output corresponding to the maximum energy deposition is crucial in effectively understanding and simulating a detector. There are a variety of fits derived in literature that will vary for every detector material. The Light Output Response Fitter, or LORF Program is a python script designed to easily and quickly compute and plot fits for a variety of scintillator light output models. It includes a stopping power library constructed from SRIM including Organic Glass, EJ309, EJ301, Stilbene, EJ276, and their deuterated counterparts by default, with the ability for the user to add custom stopping power libraries. The user is also capable of importing the python package and utilizing its in-built functions as appropriate. Uses for this capability include plotting and computing a model with known parameters.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Characterization of Crystal Properties and Defects in CdZnTe Radiation Detectors

CdZnTe-based detectors are highly valued because of their high spectral resolution, which is an essential feature for nuclear medical imaging. However, this resolution is compromised when there are substantial defects in the CdZnTe crystals. In this study, we present a learning-based approach to determine the spatially dependent bulk properties and defects in semiconductor detectors. This characterization allows us to mitigate and compensate for the undesired effects caused by crystal impurities. We tested our model with computer-generated noise-free input data, where it showed excellent accuracy, achieving an average RMSE of 0.43% between the predicted and the ground truth crystal properties. In addition, a sensitivity analysis was performed to determine the effect of noisy data on the accuracy of the model.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1989

Temperature dependence of penetration depth in thin film niobium

A novel technique is presented which should allow precise determination of the temperature dependence of the inductance, and hence of the penetration depth, of superconducting niobium thin-film structures. Four niobium thin-film stripline inductors are arranged in a bridge configuration, and inductance differences are measured using a potentiometric technique with a SQUID (superconducting quantum interference device) as the null detector. Numerical simulations of the stripline inductances are presented which allow the performance of the measurement technique to be evaluated. The prediction of the two-fluid model for the penetration-depth temperature dependence is given for reduced temperatures of 0.3 to 0.9. The experimental apparatus and its resolution and accuracy are discussed.

More, N.↗
NASA NTRS1990

HEAO 1 A-2 low-energy detector X-ray spectra of the Cygnus Loop

The Cygnus Loop supernova remnant was observed by the A-2 low-energy detector (LED) proportional counters on the HEAO 1 satellite. Recent improvements to the non-X-ray background rejection and detector response simulation have allowed production of the most accurate spectra of the Cygnus Loop to date. Three separate regions of the Cygnus Loop were observed. Single-temperature, Raymond-Smith models are inadequate to describe the spectra, but two component model fits are good. Temperature, column density, and emission measure variations across the Cygnus Loop are found. These results are interpreted and compared with previous work.

Leahy, D. A.↗
NASA NTRS1992

HEAO-1 analysis of Low Energy Detectors (LED)

The activities at Penn State University are described. During the period Oct. 1990 to Dec. 1991 work on HEAO-1 analysis of the Low Energy Detectors (LED) concentrated on using the improved detector spectral simulation model and fitting diffuse x-ray background spectral data. Spectral fitting results, x-ray point sources, and diffuse x-ray sources are described.

Nousek, John A.↗
NASA NTRS2001

LDCM Preliminary Thermal Trades

The expected cost of adding thermal bands to the next generation Landsat Data Continuity Mission (LDCM) could be significant. This viewgraph presentation investigates both traditional cooled cross-track scanners and new architectures (cooled and uncooled) which could enable a low cost thermal capability. The presentation includes surveys of applications of Landsat thermal data and the architecture of thermal instruments. It also covers new thermal architecture sensor trades, ALI Architecture with Uncooled TIR Detectors, and simulated thermal imagery.

Ryan, Robert↗
NASA NTRS2006

Sensor And Method For Detecting A Superstrate

Method and apparatus are provided for determining a superstrate on or near a sensor, e.g., for detecting the presence of an ice superstrate on an airplane wing or a road. In one preferred embodiment, multiple measurement cells are disposed along a transmission line. While the present invention is operable with different types of transmission lines, construction details for a presently preferred coplanar waveguide and a microstrip waveguide are disclosed. A computer simulation is provided as part of the invention for predicting results of a simulated superstrate detector system. The measurement cells may be physically partitioned, nonphysically partitioned with software or firmware, or include a combination of different types of partitions. In one embodiment, a plurality of transmission lines are utilized wherein each transmission line includes a plurality of measurement cells. The plurality of transmission lines may be multiplexed with the signal from each transmission line being applied to the same phase detector. In one embodiment, an inverse problem method is applied to determine the superstrate dielectric for a transmission line with multiple measurement cells.

Arndt, G. Dickey↗
DOE OSTI2018

Temporal and Spatial Shaping of X-Ray Free-Electron Lasers

The x-ray free-elec­tron laser is the bright­est source of x-rays, with a peak bright­ness ten or­ders of mag­ni­tude higher than con­ven­tional syn­chro­tron ra­di­a­tion sources. Much like con­ven­tional lasers, XFELs are ex­tremely flex­i­ble ma­chines and the prop­er­ties of the x-rays can be con­trolled by ac­cu­rately ma­nip­u­lat­ing the las­ing medium, i.e. the elec­tron beam. In my talk I will dis­cuss past and pre­sent re­search on shap­ing the tem­po­ral prop­er­ties of the x-rays at the Linac Co­her­ent Light Source (LCLS). I will dis­cuss the two-color FEL modes and their ap­pli­ca­tions in user ex­per­i­ments. Fi­nally I will pre­sent our re­sults on laser-shap­ing of x-ray pulses and our plans for at­tosec­ond op­er­a­tion in the soft x-ray regime.

ion, electron, laser, simulation, detector↗
DOE OSTI2023

Comparison of Measured and Simulated Neutron Counting with 3He Detectors and the Subcritical Water-Moderated UO2 7uPCX Assembly

An experiment designed to compare neutron noise analysis techniques on subcritical assemblies using differing neutron detector designs was developed as a collaborative effort between the Institut de radioprotection et de surete nucleaire (IRSN), Los Alamos (LANL), Lawrence Livermore (LLNL), and Sandia National Laboratories. This experiment has the final goal of characterizing neutron noise analysis accuracy in determining multiplication in light water systems for various neutron detection systems. This experiment utilized the Seven Percent Critical Experiment (7uPCX) facility at Sandia National Laboratories. The 7uPCX is an assembly designed to investigate light water systems with fuel enrichment above 5% and is able to use square or hex grid plates with varying pitches.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Machine Learning for DUNE Supernova Trigger

One of the major scientific goals of the Deep Underground Neutrino Experiment (DUNE) is to detect and measure the neutrino flux from galactic core-collapse supernovae. These neutrinos, which exist in the low energy range of up to a few tens of MeV and are responsible for carrying away over 99% of the gravitational binding energy of the supernova, provide an opportunity to study the end of life evolution of massive stars, as well as unique properties and interactions of neutrinos. Because galactic supernovae are expected to occur only on the timespan of every few decades, it is crucial that DUNE is able to detect supernova neutrino interactions when they occur. However, detecting these supernova interactions requires sifting through a large amount of data, and DUNE detectors require a trigger to signal when supernova neutrino events occur. Machine learning provides a potential approach to creating this trigger. This project generates ADC and ground truth images of neutrino interactions in a LArTPC detector as simulated by the Model of Argon Reaction Low Energy Yields (MARLEY) to be used for machine learning. The eventual goal of this work is to facilitate DUNE s detection of supernova neutrino interactions by building a machine learning pipeline to train the trigger algorithm.

Damish, Stephanie↗
DOE OSTI2023

DRiFT - Release 2.1.0: Organic Scintillators and Gas Detectors

DRiFT (a Detector Response Function Toolkit) is LANL-developed software that post-processes output from the extensively validated radiation transport code, MCNP, and generates realistic nuclear instrumentation response. DRiFT is designed to be flexible, enabling users to specify detector type and many experimental settings, as well as accommodating the addition of their own desired features. The focus of this release is on organic scintillator, gas detector, and associated capabilities, while semiconductor features are still under development. Organic scintillators are widely used in the areas of nuclear safeguards and nuclear non-proliferation efforts. DRiFT has several diagnostic and detector physics features relevant to detailed scintillator simulations including: tracking source particle information, scintillation light production, the effects of PMT quantum efficiency and gain, and digitizer settings. Users can select responses from many scintillator and PMT types supported natively by DRiFT, or add their own by following the instructions in this document. DRiFT also has several diagnostic and detector physics features relevant to neutron gas detector simulations including: gas detector wall effects, inactive areas at the end of detector tubes, and effects of a preamplifier. We acknowledge that DRiFT is under active development, bug reports and general questions and comments should be directed to Madison Andrews, madison@lanl.gov. This manual is divided into four parts: I) An overview of DRiFT, including how to obtain and install the executable, II) A description of the detector physics related to scintillators available, III) a description of more general DRiFT features the user may find useful, and IV) a description of the test suite and examples made available with the code release.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Monte Carlo Simulation of Background and Source Measurements with CSG and CAD Geometries

Detecting radioactive sources in an urban environment is difficult due to the large magnitude and variability of the background radiation. To support the search mission of the National Nuclear Security Administration, a project was undertaken to determine if first-principles modeling and simulation could be used to accurately predict the response of radiation detectors in urban environments. This study demonstrates that the simulated detector responses to photon radiation from both an isotopic source and the background compare well to benchmark-quality measurements in a large urban-like test environment. Simulation results using a traditional combinatorial solid geometry and a CAD model generated from LiDAR measurements gave very similar detector responses. With this validation, further simulations could be used to predict detector responses for various situations in real urban settings.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2012

Intelligent Detector Design

As the complexity and resolution of imaging detectors increases, the need for detailed simulation of the experimental setup also becomes more important. Designing the detectors requires efficient tools to simulate the detector response and reconstruct the events. We have developed efficient and flexible tools for detailed physics and detector response simulation as well as event reconstruction and analysis. The primary goal has been to develop a software toolkit and computing infrastructure to allow physicists from universities and labs to quickly and easily conduct physics analyses and contribute to detector research and development. The application harnesses the full power of the Geant4 toolkit without requiring the end user to have any experience with either Geant4 or C++, thereby allowing the user to concentrate on the physics of the detector system.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗