Pulse Shape Discrimination measurements using the TOFPET2 ASIC with the SensL J- series Silicon Photomultiplier for Pixelated Neutron Detector Readout
Abstract not provided.
Publications
Warhead COGNIZANT - NSARD FY21
Abstract not provided.
Deployment of a double scatter system for directional detection of background neutron radiation
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
The detection of special nuclear materials (SNM) requires the understanding of nuclear signatures that allow the discrimination against background. In particular, understanding neutron background characteristics such as count rates and energies and their correlations with environmental conditions and surroundings of measurement locations is important in enhancing SNM detection capabilities. The Mobile Imager of Neutrons for Emergency Responders (MINER) was deployed for 8 weeks in downtown San Francisco (CA) to study such neutron background characteristics in an urban environment. Of specific interest was the investigation of the impact of surrounding buildings on the neutron background count rates and to answer the question whether buildings act as absorber of neutrons or as sources via the so-called ship effect. MINER consists of 16 liquid scintillator detector elements and can be operated as a neutron spectrometer, as a neutron imager, or simply as a counter of fast neutrons. As expected, the neutron background rate was found to be inversely proportional to the atmospheric pressure. In the energy range where MINER is most sensitive, approximately 1–10 MeV, it was found that the shape of the detected background spectrum is similar to that of a detected fission spectrum, indicating the limited discrimination power of the neutron energy. The similarities between the detected background neutron spectrum and fission sources makes it difficult to discriminate SNM from background based solely on the energies observed. The images produced using maximum likelihood expectation maximization revealed that neutrons preferentially are coming from areas in the environment that have open sky, indicating that the surrounding buildings act as absorbers of neutrons rather than sources as expected by the ship effect. The inherent properties of a neutron scatter camera limit the achievable image quality and the effective deployment to systematically map neutron background signatures due to the low count rate.
Pixelated Silicon Photomultipler readout and organic scintillator detector assemblies
Abstract not provided.
Deployment of a double scatter system for directional detection of background neutron radiation
Abstract not provided.
Extension of the neutron scatter camera sensitivity to the ∼ 10-200 MeV neutron energy range
Review of Scientific Instruments
The Neutron Scatter Camera (NSC) is a neutron spectrometer and imager that has been developed and improved by the Sandia National Laboratories for several years. Built for special nuclear material searches, the instrument was configured by the design to reconstruct neutron sources within the fission energy range 1-10 MeV. In this work, we present modifications that attempt to extend the NSC sensitivity to neutron energies in the range ∼10-200 MeV and discuss the corresponding consequences for the event processing. We present simulation results that manifest important aspects of the NSC response to those intermediate energy neutrons. The simulation results also evidence that the instrument's spectroscopic capabilities severely deteriorate at those energies, mainly due to the uncertainties in measuring energy, time, and distance between the two neutron scattering interactions. This work is motivated by the need to characterize neutron fluxes at particle accelerators as they may represent important backgrounds for neutrino experiments.
Feasibility of Single-sided 3D elemental imaging
We present single-sided 3D image reconstruction and neutron spectrum of non-nuclear material interrogated with a deuterium-tritium neutron generator. The results presented here are a proof-of-principle of an existing technique previously used for nuclear material, applied to non-nuclear material. While we do see excess signatures over background, they do not have the expected form and are currently un-identified.
Source detection at 100 meter standoff with a time-encoded imaging system
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
We present the design, characterization, and testing of a laboratory prototype radiological search and localization system. The system, based on time-encoded imaging, uses the attenuation signature of neutrons in time, induced by the geometrical layout and motion of the system. We have demonstrated the ability to detect a ∼1mCi252Cf radiological source at 100m standoff with 90% detection efficiency and 10% false positives against background in 12min. This same detection efficiency is met at 15s for a 40m standoff, and 1.2s for a 20m standoff.
Quantitative Advanced Data Analysis for Neutron Scatter Cameras
Abstract not provided.
Additional capabilities of a compact neutron scatter camera: Active interrogation, time-correlated pulse-height multiplication measurements, and gamma imaging
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015
Our previous conference report on this instrument emphasized its use for fast-neutron imaging spectroscopy. We describe here its additional measurement capabilities, namely active interrogation, time-correlated pulse-height multiplication measurements, and gamma imaging.
Compact Neutron Scatter Camera Search Applications
Abstract not provided.
System Construction of the Stilbene Compact Neutron Scatter Camera
This report documents the construction of a stilbene-crystal-based compact neutron scatter camera. This system is essentially identical to the MINER (Mobile Imager of Neutrons for Emergency Responders) system previously built and deployed under DNN R&D funding,1 but with the liquid scintillator in the detection cells replaced by stilbene crystals. The availability of these two systems for side-by-side performance comparisons will enable us to unambiguously identify the performance enhancements provided by the stilbene crystals, which have only recently become commercially available in the large size required (3” diameter, 3” deep).
Emergency Response Demonstration: MINER (Mobile Imager of Neutrons for Emergency Responders) Measurements
Abstract not provided.
Compact Stilbene Neutron Scatter Camera
Abstract not provided.
Emergency Response Demonstration: MINER (Mobile Imager of Neutrons for Emergency Responders) Measurements
Abstract not provided.
MINER - A mobile imager of neutrons for emergency responders
2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014
Our research group has been developing a fast neutron imaging platform to enhance the capabilities of emergency responders in the localization and characterization of special nuclear material. This mobile imager of neutrons for emergency responders (MINER) is a compact neutron scatter camera optimized to provide omni-directional (4-Pi) imaging with only a ~twofold decrease in sensitivity compared to our much larger neutron scatter cameras. The system performance is tuned for fission energy neutron imaging and spectroscopy, and it also can function as a Compton camera for gamma imaging. Results will be presented relating to detector response as well as several measurement campaigns at external facilities.
Demonstration of two-dimensional time-encoded imaging of fast neutrons
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
We present a neutron detector system based on time-encoded imaging, and demonstrate its applicability toward the spatial mapping of special nuclear material. We demonstrate that two-dimensional fast-neutron imaging with 2° resolution at 2 m stand-off is feasible with only two instrumented detectors.
Fast Neutron Backgrounds for Anti-Neutrino Based Nuclear Reactor Monitoring as a Function of Overburden
Abstract not provided.
Feasibility Demonstration of Two-Dimensional Time-Encoded Fast Neutron Imaging Using a Single Detector Pixel
Abstract not provided.
Additional Capabilities of a Compact Neutron Scatter Camera: Active Interrogation Time-Correlated Pulse-Height Multiplication Measurements and Gamma Imaging
Abstract not provided.
Fast Neutron Backgrounds as a Function of Depth Underground
Abstract not provided.
NSC measurements at SNS
Abstract not provided.
MINER ? A Mobile Imager of Neutrons for Emergency Responders
Abstract not provided.
Comparsion of Stilbene neutron detection performance to EJ-309
Abstract not provided.
MINER - A Mobile Imager of Neutrons for Emergency Responders
Abstract not provided.
Results 1–25 of 73