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At least 19 records

Unattended Monitoring of Uranium Holdup with Scintillating Fibers

This work evaluated the use of scintillating fiber (SciFi) radiation sensors as a cost-effective, unattended monitoring technique for uranium holdup accumulation in reprocessing equipment. With ruggedized packaging and an outer diameter of less than 1 cm, scintillating fibers offer deployment flexibility. Additionally, plastic scintillating fibers coupled with standard optical fibers provide an affordable option to monitor locations kilometers away from a localized control room or data acquisition (DAQ) system. These combinations of characteristics along with their relatively low manufacturing costs make scintillating fibers ideal for installation at key measurement points such as pipes, valves, and filtration systems.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗

Long-length Scintillating Fibers for Nuclear Waste Repositories (Conference Record)

This paper describes the fabrication, testing, and characterization of long-length, up to 50 m, scintillating fibers for the purpose of radiation monitoring in inaccessible radiological and nuclear waste repositories. The fabrication aspect was focused on ruggedizing the 1-mm diameter fiber and limiting external light interference for fibers. Testing and characterization were performed in a laboratory setting with radiation sources, a photosensor module and a multi-channel analyzer. Light attenuation was studied as a function of distance by analyzing both the spectrum and count rate. Additionally, the scintillating fibers were coupled to optical communication fibers (100 m) to extend the reach of the system. This paper also includes the optical spectrometry results from the sensitivity and response of the signal attenuation. Lastly, the paper covers the field testing of the scintillating fibers in a relevant environment.

47 - OTHER INSTRUMENTATION↗

Characterization and Evaluation of Scintillating Fiber System Components

Idaho National Laboratory is studying long scintillation fibers (SF) in a project called “TRIPWIRE” which aims to verify containment in inaccessible nuclear waste repositories. This system will continuously monitor ionizing radiation, electromagnetic fields, and seismic activity in the vicinity of nuclear waste. Previous experiments have determined a better alternative to long SF is to couple shorter SF to kilometer scale optical fiber (OF) to reach electronics far outside of the repository. Minor signal attenuation from coupling these fibers has been observed using optical spectrometry. This experiment characterized two photomultiplier tubes (PMT) to reduce this loss by matching their spectral response characteristics to the SF’s emission spectrum. The experiment created a comparison between the two PMTs showing results that suggest other characteristics are playing a major role in improving signal attenuation when the SF is coupled to OF.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗

Long-length Scintillating Fibers for Nuclear Geological Repositories

This research focuses on the usage of plastic scintillating fibers as ruggedized detectors in long-length sections coupled to long-length standard optical fiber segments for the purpose of radiation detection and monitoring. This technology addresses a need for monitoring radiation in difficult-to-access or inaccessible areas, such as monitoring: radioactive waste within geological repositories, nuclear material storage facilities, spent fuel dry storage areas, inaccessible areas within nuclear facilities including reactors and reprocessing facilities, decommissioning of nuclear facilities, and other similar areas. The fiber can be placed along the tunnels of a geological repository to monitor the radiation field along its length. This can detect an increase of radiation due to movement, leakage, or unexpected opening of the containers, as well as decrease in the radiation due to removal of material. These capabilities have been demonstrated at INL’s Radioactive Scrap Waste Facility by successfully detecting the removal of an interim storage containers from the storage area. The poster focuses on explaining the technology and its capability in monitoring deep geological repositories (DGRs), especially in the domain of safety and international safeguards. As more countries consider the development of DGRs, technologies such as the one being presented can help establish continuity of knowledge of the material, maintain public confidence, and ensure safe operation of the facility. Furthermore, the poster looks at the future steps of the technology and its potential role in the international safeguards regime.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗

Evaluation of the response to electrons and pions in the scintillating fiber and lead calorimeter for the future electron-ion collider

The performance of the Baby Barrel Electromagnetic Calorimeter (Baby BCAL) — a small-scale lead-scintillating-fiber (Pb/ScFi) prototype of the GlueX Barrel Electromagnetic Calorimeter (BCAL) — was tested in a dedicated beam campaign at the Fermilab Test Beam Facility (FTBF). This study provides a benchmark for the Pb/ScFi component of the future Barrel Imaging Calorimeter (BIC) in the ePIC detector at the Electron-Ion Collider (EIC). The detector response to electrons and pions was studied at beam energies between 4 and 10 GeV, extending previous GlueX tests to a higher energy regime. The calibrated detector exhibits good linearity within uncertainties, and its electron energy resolution meets EIC requirements. The data further constrain the constant term in the energy resolution to below 1.9%, improving upon previous constraints at lower energies. Simulations reproduce key features of the electron and pion data within the limitations of the collected dataset and the FTBF test environment. Electron-pion separation in the test beam setup was analyzed using multiple methods, incorporating varying degrees of beam-related effects. The inclusion of longitudinal shower profile information enhanced the separation performance, underscoring its relevance for the full-scale BIC in ePIC. These results provide essential benchmarks for the Pb/ScFi section of the future BIC, validating detector simulations and guiding optimization strategies for electron-pion discrimination.

47 OTHER INSTRUMENTATION↗

Low Energy Muon Beam Diagnostics: Scintillating Fiber Profile Monitor

The MeV Test Area (MTA) houses the 400 MeV H- Beam at the end of the Linac and a secondary beamline of muons and pions created from hitting a Tungsten target. The MTA is in the Irradiation Test Area (ITA), where experiments involve studying the effects of radiation on materials in the MTA beam. There is a need for a retractable detector to monitor the secondary beam’s intensity and coarse profile. The SFPM was chosen when considering factors like ability to measure low rates and handle high intensities. The plan was to test different scintillating fibers & Silicon Photomultiplier (SiPM) models to figure out which combination gives the best signals, and gain familiarity with the detector assembly, operation, and data acquisition software before using with final detectors in beamline. The SiPM circuit has been tested with a LED pulser successfully. The immediate steps that follow will be to set the SiPM up on the monitor with three different types of optical fibers, use the Caen software to configure the best mode of data acquisition, and proceed with an offline source test using Strontium-90. Once the most efficient measurement method is clear, they will be ready for use in the beamline.

Leith, Justin↗

Low Energy Muon Beam Diagnostics - Scintillating Fiber Profile Monitor (SFPM)

The MeV Test Area (MTA) houses the 400 MeV H^− Beam at the end of the Linac and a secondary beamline of muons and pions created from hitting a Tungsten target. The MTA is in the Irradiation Test Area (ITA), where experiments involve studying the effects of radiation on materials in the MTA beam. There is a need for a retractable detector to monitor the secondary beam s intensity and coarse profile. The SFPM was chosen when considering factors like ability to measure low rates and handle high intensities. The plan was to test different scintillating fibers & Silicon Photomultiplier (SiPM) models to figure out which combination gives the best signals, and gain familiarity with the detector assembly, operation, and data acquisition software before using with final detectors in beamline. The SiPM circuit has been tested with a LED pulser successfully. The immediate steps that follow will be to set the SiPM up on the monitor with three different types of optical fibers, use the Caen software to configure the best mode of data acquisition, and proceed with an offline source test using Strontium-90. Once the most efficient measurement method is clear, they will be ready for use in the beamline.

Leith, Justin↗

Fact Sheet - Long-length Scintillating Fibers for Radiation Detection

As the world looks to underground geological repositories for storing nuclear waste, technologies to safeguard the material are needed. An example of a project that developed a new technology is Tripwire. Tripwire proposes a multi-sensor system approach for geological spent nuclear fuel repositories that relies of radiation, vibration, and electromagnetic detection. Tripwire was developed by the Applied Radiation Measurements and Systems (ARMS) group at INL and sponsored by the National Nuclear Security Administration (NNSA). The ARMS group performs research and development, testing and evaluation, operational support, and training focused on applied ionizing radiation detection and measurement. Application areas include nuclear engineering for advanced reactors and fuel cycle operations, nuclear nonproliferation, nuclear counterproliferation, nuclear forensics, and arms control and disarmament.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗

The GlueX beamline and detector

The GlueX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 $μs$. The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. Here, we describe the photon beam, the GlueX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Progress of Tripwire: Multi-Modal Distributed Sensing for Repository Verification

This project is developing and demonstrating a multi-modal sensor system, TRIPWIRE, for containment verification in inaccessible radiological and nuclear waste repositories. The TRIPWIRE system will continuously monitor ionizing radiation and electromagnetic fields in the vicinity of emplaced nuclear materials buried in a repository, reporting on disturbances with a real-time alarm control station. The system will use long-length scintillating fiber bundles (SFBs) to perform area radiation monitoring; these will be coupled to kilometer-scale multimodal optical communication fibers – all light sensors and electronic components used with this system will be located above ground. Electromagnetic fields, and changes in local dielectric conditions caused by intrusion and soil movement, will be monitored using commercial grade, ported "leaky" coaxial cables (PCCs), with control electronics also located above ground. This paper documents the results of the simulations and modeling efforts that have helped identify the optimal placement of the SFBs. Additionally, the paper includes the current progress on the multi-modal SFB-PCC system, including the fabrication of long-length (>3-m) fibers and their coupling to optical fibers.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗

Parameters of fast and high-yield InAs/GaAs quantum dot semiconductor scintillator

InAs quantum dots (QDs) embedded into a waveguiding GaAs semiconductor matrix may produce scintillation detectors with exceptional speed and yield, making them valuable for nuclear security, medical imaging, and high energy physics applications. In this work, we developed thick (~25 μm) epitaxial heterostructres with high luminescence efficiency composed of self-assembled nano-engineered InAs QDs grown by molecular beam epitaxy. Here, the bulk GaAs acts as a stopping material for incident particles and as a waveguide when layer-transferred onto a low-index substrate. Waveguiding and self-absorption (< 1 cm –1 ) were studied using photoluminescence with scanning laser excitation and modeled with ray optics approximation and geometrical coupling of high-index waveguide to a collection fiber. Scintillating signals from α-particles were analyzed with an external photodiode (PD) and an integrated PD which provided an improved optical coupling. The mean charge collected by the integrated PD corresponded to 3 × 10 4 photoelectrons per 1 MeV of deposited energy, or ~13% of the theoretically achievable light yield. Combined with the previously measured QD scintillation time of 0.3-0.6 ns, this makes the InAs/GaAs QD heterostructures the fastest high yield scintillation material reported.

36 MATERIALS SCIENCE↗

Performance of Scintillation Detectors Based on Quantum Dots in a Semiconductor Matrix (Final Technical Report)

InAs Quantum Dots (QDs) embedded into GaAs semiconductor waveguide have unique scintillation properties, valuable for nuclear security, medical imaging, and high energy physics. In this work, we developed thick (~25um) epitaxial heterostructres with high luminescence efficiency composed of self-assembled nano-engineered InAs QDs grown by molecular beam epitaxy. In this type of detector, the GaAs matrix acts as a stopping material for charged particles or photons generating electrons captured by the QDs acting as luminescence centers. The QD medium is designed to provide fast capture of electrons into QDs (few ps), high QD luminescence efficiency at room temperature (>50%), and strong red-shift of photoluminescence (PL) from the GaAs absorption edge (>250nm). Typical devices consist of a 10-25um thick GaAs layer with embedded sheets of modulation p-type doped InAs QDs and an InGaAs photodetector tuned to the QD emission wavelength. The thick GaAs layer acts also as a waveguide when layer-transferred onto a low-index substrate. Waveguiding and self-absorption (~1cm -1 ) were studied using photoluminescence with scanning laser excitation and modeled with ray optics approximation and geometrical coupling of high-index waveguide to a collection fiber. Scintillating signals from α-particles were analyzed with both an external photodiode (PD) and an integrated PD which provided an improved optical coupling. In the former case, the external InGaAs PD was air-coupled to the scintillator and had the light collection efficiency of about 1% corresponding to limited light extraction through a planar interface with air due to total internal reflection. The mean charge collected by the integrated PD was in the range of (3÷5)×10 4 photoelectrons per 1 MeV of deposited energy, or ~13-20% of the theoretically achievable light yield. Timing of the integrated device was measured by wire-bonding it to the input of an 8 GHz IC. The scintillation response shows an extremely fast 0.3-0.6 ns decay constant and about 40-70 ps time resolution, limited by the system noise. The combined light yield and decay time makes the InAs/GaAs QD heterostructures the fastest high yield scintillation material reported making it valuable for high energy physics and medical imaging applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

A profile monitor for proton radiography experiments at the Los Alamos Neutron Science Center

The Proton Radiography (pRad) facility at the Los Alamos Neutron Science Center utilizes pulses of protons delivered by the 800 MeV linear accelerator to produce a series of radiographic images to study the dynamic behavior of materials under extreme conditions. Radiographs taken with an empty field of view, or beam pictures, are used to normalize transmission. However, because the center of the proton beam shifts between pulses, an in situ method for measuring beam position is required to normalize images for beam movement to perform absolute radiography. The beam profile monitor described here uses an array of scintillating fibers positioned in the beam path to produce light proportional to beam intensity across the beam cross section. This light is detected using fast photodiodes and a digital oscilloscope, providing a response time of several nanoseconds—suitable for measuring the 50-ns proton pulses used in pRad. The profile monitor achieves a measured position precision of 40 μm and an intensity precision of 0.7%, allowing for beam movement corrections to be applied to images, thereby improving data accuracy and image quality.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Erratum: Production and validation of scintillating structural components from low-background Poly(ethylene naphthalate)

Regretfully, the author list of the original paper did not contain the members of the groups being responsible for the HPGe screening, Radon emanation measurement and ICPMS surface characterization works. As the work performed is to be considered more than “just service work”, the authors together with the members of these groups have decided to amend the authors list. At publication the following authors were not included in the author list: • From Pacific Northwest National Laboratory, Richland, WA, U.S.A.: E.W. Hoppe, I.J. Arnquist, K.P. Hobbs, A.D. French, M.L. diVacri • From INFN, Laboratori Nazionali del Gran Sasso, 67100 Assergi, Italy: M. Laubenstein • From M. Smoluchowski Institute of Physics, Jagiellonian University, 30-348 Krakow, Poland: G. Zuzel The metadata of the present erratum are already correct.

99 GENERAL AND MISCELLANEOUS↗

TRIPWIRE – Deployment and Field-Testing Report

TRIPWIRE is a multi-modal system for containment verification in inaccessible radiological and nuclear waste repositories. The sensing modes are focused on radiation, electromagnetic and vibration. The radiation detection component has been developed over the last three years at Idaho National Laboratory (INL). This development has focused on the fabrication, characterization, and testing of long-length (greater than 10-m) plastic scintillating fibers. This fiscal year, the focus of TRIPWIRE has been on field testing and demonstration of the radiation sensing component in a relevant environment. After reviewing the static storage facilities at INL, the Radioactive Scrap Waste Facility (RSWF) south storage area outside the Materials and Fuels Complex (MFC) was selected due to its periodic changes in configuration and inventory. This report summarizes the research outcomes for the work performed in fiscal year (FY) 2023.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗