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At least 1,117 records · Page 62
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Synthesis and luminescence of the BaFCl:Eu 2+ scintillator system

X-ray imaging capabilities play a vital role in the medical industry, thus incentivizing the need for advanced device development. BaFCl:Eu 2+ is a promising material for scintillating composites applicable to pixelated X-ray imaging technology. Crystalline Eu(II)-doped BaFCl was synthesized via flux growth techniques with commercial reagents. The synthesis yield was separated into particle size subsets, and photo-luminescence (PL) spectra were obtained for each particle size range. Under UV irradiation, electronic transitions centered at 365 nm, 390 nm, and 430 nm were observed. Particle sizes <38 μm showed a significant drop in the characteristic Eu 2+ ion emission and a more intense emission near 430 nm. X-ray diffraction (XRD) analysis revealed the presence of a secondary phase, Ba 12 F 19 Cl 5 , and demonstrated that the introduction of this phase is dependent on synthesis parameters.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Optical properties of BaFCl:Eu 2+ scintillating composites for X-ray imaging screens

The development of composite scintillating materials is necessary for the optimization of advanced pixelated X-ray imaging technology. Polycrystalline BaFCl:Eu 2+ was synthesized via a flux growth technique and its emission properties were characterized through photo-luminescence (PL) spectroscopy and time-correlated single photon counting (TCSPC). PL emission wavelengths were observed at 365 nm, 383 nm, and 430 nm under UV excitation. Composite pastes, consisting of BaFCl:Eu 2+ powder and NOA1665 UV-curable resin, were fabricated and subsequently analyzed through absorption and radio-luminescence (RL) spectroscopy. An interchange of transmissivity and light production, resulting from differences in the amount of solvent and resin in the composite, was observed in fabricated composites.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Weekly Update -- Scintillators and Mobile Imaging System

The Neutron Imaging (NI) project is developing innovative tools that will allow multimodal imaging and high-quality CT imaging of dense objects. To realize these goals a Flat Panel Detector (FPD) has been procured and novel scintillating materials are being investigated. A compact, mobile neutron imaging system is being designed and components procured

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Design and Evaluation of a Pixelated PSD-capable Scintillator Detector with SiPM Readout

We present the detector response comparison between a 10x10 pixellated array of scintillator read out with Anger logic using four 2" Hamamatsu R7724-100 super bialkali photomultiplier tubes (PMT) and a custom Silicon photomultiplier (SiPM) board consisting of 100 C-series 6x6 mm SiPMs from SensL. An array of these pixellated detectors are currently used in the Neutron Coded Aperture (NCA) imaging system. The energy, timing and pulse shape discrimination response using both readout schemes are presented, along with an analysis of multiple scatter events occurring within the block. An evaluation of the impact of photodetector readout on the overall detection efficiency and imaging accuracy is presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

A new scintillation hodoscope for CLAS12 and partial wave analysis of the channel yp &rarr; pK + K -

This thesis consists of two parts that have contributed to a new meson spectroscopy program, MesonEx, which is currently taking place in Hall B of the upgraded Thomas Jefferson National Accelerator Facility (JLab) in the USA. The first, hardware part, presents design, testing, construction and calibration of a fast-timing scintillation Hodoscope for a new Forward Tagger detector, that has been installed inside the upgraded CEBAF Large Acceptance Spectrometer (CLAS12) which is situated in the Hall B of JLab. The Forward Tagger is a key apparatus for measurement of quasi-real photoproduction of mesons in the MesonEx, and a necessary device for other new hadron spectroscopy programs. The second, software and analysis part, presents contributions to the general HAdron SPEctroscopy CenTre (HASPECT) analysis framework, that has been developed in preparation for the MesonEx data analysis. The software contribution consists of finalizing HASPECT simulation and analysis chains in a model-independent way, and developing a mass-independent partial wave analysis procedure. This procedure has been tested via analysis of the γ p &rarr; pK + K - channel from the g 11 a CLAS data, in the photon energy range E γ = 3.0-3.8 GeV and momentum transfer squared range -t = 0.6 - 0.7 (GeV/c 2 ) 2 . The first result of this analysis is the differential cross section for the &straightphi;(1020) resonance photoproduction. This result has been compared with a previous analysis result, and a good agreement has validated the developed analysis procedure. Furthermore, S , P and D partial waves have been extracted from the data set, using the same procedure, and ambiguous solutions for these partial waves have been calculated, using the method of Barrelet zeros which is for the first time applied to photoproduction of the K + and K - mesons on the proton. Distributions of the calculated solutions have been compared with the fit results. It is found that the physical solution contains contributions of the &straightphi;(1020) in the P -wave and the a 2(1320) in the D -wave.

Stankovic, Ivana↗
DOE OSTI2012

Secondary Emission Chamber Calibration with Scintillator (V.1.0)

We report on a study of the behavior of a secondary emission chamber (SEC) when placed in a beam of high energy charged particles. We show the dependence of the SEC signal on the charge and velocity of the primary beam particles when using protons, and Iron ions. We calibrate the response of the SEC to ions by first using a plastic scintillator to count particles traversing the SEC, and transfer the calibration to an ion chamber that can operate at a high enough rate to characterize the SEC. The calibration is determined for the two different ion species and two different energies

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Scintillators

As concerns about the illicit movement of radioactive materials across international borders increase, so too has the need for increased protection of those borders both foreign and domestic. The challenge is not only to detect hidden radioactive materials, but also to distinguish them from legitimate radionuclides such as radio-pharmaceuticals that are often transported across borders and shipped throughout a country. With more than 600 U.S. border sites to protect, screening imported radioactive material requires a careful balance of high throughput and high search efficiency. However, these requirements are difficult to meet as rapid screening operations leave less time for radiation detectors to efficiently evaluate materials. In support of border security, Sandia developed organic glass scintillators.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Design of a Cryogenic Scintillation Neutrino Detector at the Spallation Neutron Source

We successfully verified in the following three aspects the feasibility of using a cryogenic scintillating crystal-based neutrino detector at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, for the detection of low-mass dark matter particles and non-standard neutrino interactions (NSIs), as part of the detector R&D effort of the COHERENT experiment. First, we demonstrated the possibility of using silicon photomultipliers (SiPMs) at cryogenic temperatures to replace traditional photomultiplier tubes (PMTs) as light sensors. Second, we verified that the high light yield of undoped CsI crystals measured above 13 keVee at 77 K still holds down to 5.9 keVee. Third, we successfully measured nuclear quenching factor of undoped cryogenic CsI at the Triangle Universities Nuclear Laboratory with the help from our Duke collaborators. The first achievement resulted in a publication in European Physics Journal C. The second resulted in an arXiv pre-print, which is under journal review. The last one indicates that the performance of the proposed detector may be better than what was assumed in the literature. The analysis is in the final stage and will result in another journal publication. In addition, two graduate students involved in this project graduated with master’s degrees during the project period. Both decided to continue their research as PhD students. One open-source data analysis code package was created and is publicly available on GitHub. A set of tutorials about Monte Carlo simulation of radiation interacting with detectors were created on YouTube, receiving more than 100,000 views.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Application of the Cohn-alpha Method on Bare Highly Enriched Uranium Using Organic Scintillators [Poster]

The prompt neutron decay constant (α), can be used to calculate the lifetime of prompt fission chains within a multiplying system and verify reactor startup and shutdown. We analyze a fast, bare system consisting of highly enriched uranium (93% 235 U) hemisphere shells known as the Measurements of Uranium Subcritical and Critical (MUSiC). We measured the system with a three by-four array of organic scintillators (OSCAR) to obtain the gamma-ray and fast neutron signals. Pulse shape discrimination was used to isolate the neutron time series data. The Cohn-α method was used to estimate α for 3 supercritical measurements of Configurations 8 MUSiC. We use these estimates to linearly extrapolate α at delayed critical. These values can be compared to highly detailed simulations in MCNP6.2.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

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↗
DOE OSTI2025

Multiple Phase Screen Scintillation Code Execution and Examples

The phenomenon of random fluctuations in the amplitude and phase of received transionospheric radio frequency (RF) signals is well known and documented. For wide band signals, sometimes a set of frequencies in the the band or even the whole band can suffer degradation or complete drop out at the receiver. The former is known as frequency selective scintillation where only a fraction of the signal bandwidth is affected, whereas the latter is known as flat fading.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Upgrade to Fixed and Translating Scintillation-Based Loss Detector System in the Fermilab Drift Tube Linac

The closed-off structure of the Fermilab Drift Tube Linac precludes a robust array of instrumentation from directly monitoring the H- beam that is accelerated from 750 keV to 116 MeV. To improve beam tuning and op-erational assessment of Drift Tube Linac performance, scintillator-based loss monitors were previously installed along the exterior of the first two accelerating cavities to assess low energy beam losses. Here we present a recent upgrade to the loss monitor system, including significant improvements in analog signal processing to address baseline-interfering noise; digitization of the signals to enable regular operational use and tuning; and a new remote operation upgrade of the translating loss monitor with precise positioning of the loss monitor along its nine-foot track. Data from the fixed and translating de-tectors collected under varying beam conditions validate the utility of the upgrade.

Chen, Erin V. [Fermilab] (ORCID:0000000215467899)↗
DOE OSTI2026

Performance and long-term stability of the ICARUS-T600 scintillation light detection system

The ICARUS-T600 Liquid Argon (LAr) Time Projection Chamber (TPC) is presently used as a far detector of the Short Baseline Neutrino (SBN) program at Fermilab (USA) to search for a possible LSND-like sterile neutrino signal at $\Delta m^2 \sim 1 eV^2$ with the Booster Neutrino Beam (BNB). A light detection system, based on 360 large area Photo-Multiplier Tubes (PMTs), has been realized for ICARUS-T600 to detect VUV photons produced after the passage of ionizing particles in LAr. This system is fundamental for the TPC operation, providing an efficient trigger and contributing to the 3D reconstruction of events. Moreover, since the detector is exposed to a huge flux of cosmic rays due to its shallow depths operations, the light detection system allows for the time reconstruction of events, contributing to the identification and to the selection of neutrino interactions within the BNB spill gate. Long-term behavior of PMT gains and timing resolution, demonstrate the robustness and reliability of the ICARUS scintillation light detection system and provide valuable input for the design and operation of future large-scale liquid argon detectors.

Raselli, Gian Luca [INFN, Perugia] (ORCID:00000002↗