Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Tl”

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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Thermoluminescence and the shock and reheating history of meteorites. IV - The induced TL properties of type 4-6 ordinary chondrites

The thermoluminescence (TL) properties were measured in 121 equilibrated H and L ordinary chondrites of which 33 H and 32 L were from Antarctica. It was found that the distribution of TL sensitivities for non-Antarctic L chondrites differs from that of non-Antarctic H chondrites, reflecting the well-known differences in shock history between L and H classes, the greater proportion of the former having suffered postmetamorphic shock. The data also show differences in TL sensitivity between Antarctic and non-Antarctic H chondrites, suggesting nontrivial differences in thermal history of these chondrites.

Haq, Munir↗
NASA NTRS1991

Chemical spray pyrolysis of Tl-Ba-Ca-Cu-O high-T(sub c) superconductors for high-field bitter magnets

The deposition of Tl-Ba-Ca-Cu-O thick films by spray pyrolyzing a Ba-Ca-Cu-O precursor film and diffusing thallium into the film to form the superconducting phase is examined. This approach was taken to reduce exposure to thallium and its health and safety hazards. The Tl-Ba-Ca-Cu-O system was selected because it has very attractive features which make it appealing to device and manufacturing engineering. Tl-Ba-Ca-Cu-O will accommodate a number of superconducting phases. This attribute makes it very forgiving to stoichiometric fluctuations in the bulk and film. It has excellent thermal and chemical stability, and appears to be relatively insensitive to chemical impurities. Oxygen is tightly bound into the systems, consequently there is no orthorhombic (conductor) to tetragonal (insulator) transition which would affect a component's lifetime. More significantly, the thallium based superconductors appear to have harder magnetic properties than the other high-Tc oxide ceramics. Estimates using magnetoresistance measurements indicate that at 77 K Tl2Ba2CaCu2O10 will have an upper critical field, H(sub c2) fo 26 Tesla for applied fields parallel to the c-axis and approximately 1000 Tesla for fields oriented in the a-b plane. Results to date have shown that superconducting films can be reproducibly deposited on 100 oriented MgO substrates. One film had a zero resistance temperature of 111.5 K. Furthermore, x ray diffraction analysis of the films showed preferential c-axis orientation parallel to the plane of the substrate. These results have now made it possible to consider the manufacture of a superconducting tape wire which can be configured into a topology useful for high-field magnet designs. The research which leads to the preparation of these films and plans for further development are reviewed.

Derochemont, L. Pierre↗
NASA NTRSDate not supplied

Designing the Imaging and Breadboard System for FBCE-TL Project

This presentation outlines the support work done on designing the imaging and breadboard system of the Transfer Line (TL) project, which is the third module for the Flow Boiling and Condensation Experiment (FBCE) operating in the Fluids Integrated Rack on-board the International Space Station (ISS). The goal of the FBCE is to serve as a facility for flow boiling and condensation investigating two-phase flow and heat transfer data in microgravity. The TL module aims use existing FBCE hardware to study cryogenic chilldown, a large component of cryogenic propellant tank transfer research. The TL test module will perform chilldown studies with normal-perfluorohexane (nPFH), a cryogenic simulant, flowing through a super-heated line, which is heated through the process of Joule-heating. SolidWorks and Creo were used to create electrically conductive pipe junctions that connect and seal several Indium Tin Oxide (ITO) coated sapphire tube sections together to allow for low leak probability fluid flow and circumferentially uniform electrical current density. It is necessary to understand and calculate the thermal expansion of the tubing sections such that the junctions would not leak at anticipated operating temperatures and pressures, would maintain electrical contact, and not crack the crystalline tubes. Optical imaging techniques were used to build an experimentally validated image remapping process for flight-like setups of cylindrical tubes. Then MATLAB was used to create an algorithm that distorts an image based on the refraction of light passing through the mediums we were imaging through to accurately visualize the cryogenic chilldown that is of scientific interest. This research will assist NASA to move forward with long-duration spaceflight missions where knowledge of efficient heat transfer processes becomes more critical.

imaging system↗
DOE OSTI2020

Materials Data on Tl(CuO)2 by Materials Project

Tl(CuO)2 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Cu+1.50+ sites. In the first Cu+1.50+ site, Cu+1.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.98 Å. In the second Cu+1.50+ site, Cu+1.50+ is bonded in a linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 1.83 Å. Tl1+ is bonded in an L-shaped geometry to two equivalent O2- atoms. Both Tl–O bond lengths are 2.48 Å. O2- is bonded in a 4-coordinate geometry to three Cu+1.50+ and one Tl1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(WO3)6 by Materials Project

Tl(WO3)6 crystallizes in the trigonal P-31m space group. The structure is three-dimensional. W+5.83+ is bonded to six O2- atoms to form WO6 octahedra that share corners with six equivalent WO6 octahedra and edges with two equivalent TlO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–29°. There is four shorter (1.93 Å) and two longer (1.96 Å) W–O bond length. Tl1+ is bonded to twelve equivalent O2- atoms to form TlO12 cuboctahedra that share edges with twelve equivalent WO6 octahedra. All Tl–O bond lengths are 3.37 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent W+5.83+ and one Tl1+ atom. In the second O2- site, O2- is bonded in a linear geometry to two equivalent W+5.83+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two equivalent W+5.83+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(CO)2 by Materials Project

CTlCO2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is two-dimensional and consists of four ethyne molecules and two TlCO2 sheets oriented in the (0, 0, 1) direction. In each TlCO2 sheet, there are two inequivalent Tl3+ sites. In the first Tl3+ site, Tl3+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Tl–O bond distances ranging from 2.67–2.84 Å. In the second Tl3+ site, Tl3+ is bonded in a 2-coordinate geometry to six O2- atoms. There are a spread of Tl–O bond distances ranging from 2.80–3.09 Å. There are two inequivalent C+0.50+ sites. In the first C+0.50+ site, C+0.50+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.27 Å) and one longer (1.28 Å) C–O bond length. In the second C+0.50+ site, C+0.50+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.27 Å) and one longer (1.28 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Tl3+ and one C+0.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Tl3+ and one C+0.50+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three Tl3+ and one C+0.50+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two Tl3+ and one C+0.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(Mo3Se4)2 by Materials Project

Tl(Mo3Se4)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Mo+2.50+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.53–2.81 Å. Tl1+ is bonded in a body-centered cubic geometry to eight Se2- atoms. There are two shorter (3.05 Å) and six longer (3.35 Å) Tl–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 10-coordinate geometry to three equivalent Mo+2.50+ and one Tl1+ atom. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to four equivalent Mo+2.50+ and one Tl1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(V3S4)4 by Materials Project

Tl(V3S4)4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are six inequivalent V+2.58+ sites. In the first V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.32–2.52 Å. In the second V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–54°. There are a spread of V–S bond distances ranging from 2.31–2.54 Å. In the third V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.32–2.55 Å. In the fourth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.33–2.51 Å. In the fifth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.33–2.51 Å. In the sixth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–54°. There are a spread of V–S bond distances ranging from 2.31–2.55 Å. Tl1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are two shorter (3.08 Å) and four longer (3.09 Å) Tl–S bond lengths. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to six V+2.58+ atoms to form distorted face-sharing SV6 pentagonal pyramids. In the second S2- site, S2- is bonded to six V+2.58+ atoms to form distorted face-sharing SV6 pentagonal pyramids. In the third S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four V+2.58+ atoms. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the fifth S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the sixth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four V+2.58+ atoms. In the seventh S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four V+2.58+ atoms. In the eighth S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(Mo3S4)2 by Materials Project

Tl(Mo3S4)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Mo+2.50+ is bonded to five S2- atoms to form a mixture of corner and edge-sharing MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.40–2.57 Å. Tl1+ is bonded in a body-centered cubic geometry to eight S2- atoms. There are two shorter (2.90 Å) and six longer (3.25 Å) Tl–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to three equivalent Mo+2.50+ and one Tl1+ atom. In the second S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent Mo+2.50+ and one Tl1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(CoSb3)16 by Materials Project

Tl(CoSb3)16 is Skutterudite-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are five inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six Sb+0.69- atoms to form CoSb6 octahedra that share corners with six CoSb6 octahedra and a faceface with one TlSb12 cuboctahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of Co–Sb bond distances ranging from 2.53–2.55 Å. In the second Co2+ site, Co2+ is bonded to six Sb+0.69- atoms to form corner-sharing CoSb6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are one shorter (2.53 Å) and five longer (2.54 Å) Co–Sb bond lengths. In the third Co2+ site, Co2+ is bonded to six Sb+0.69- atoms to form corner-sharing CoSb6 octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are two shorter (2.53 Å) and four longer (2.54 Å) Co–Sb bond lengths. In the fourth Co2+ site, Co2+ is bonded to six Sb+0.69- atoms to form corner-sharing CoSb6 octahedra. The corner-sharing octahedral tilt angles are 52°. All Co–Sb bond lengths are 2.54 Å. In the fifth Co2+ site, Co2+ is bonded to six Sb+0.69- atoms to form CoSb6 octahedra that share corners with six CoSb6 octahedra and faces with two equivalent TlSb12 cuboctahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are two shorter (2.54 Å) and four longer (2.55 Å) Co–Sb bond lengths. Tl1+ is bonded to twelve Sb+0.69- atoms to form TlSb12 cuboctahedra that share faces with eight CoSb6 octahedra. There are four shorter (3.40 Å) and eight longer (3.41 Å) Tl–Sb bond lengths. There are sixteen inequivalent Sb+0.69- sites. In the first Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ atoms. In the second Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ atoms. In the third Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ atoms. In the fourth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ and one Tl1+ atom. In the fifth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ and one Tl1+ atom. In the sixth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ atoms. In the seventh Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ atoms. In the eighth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two Co2+ atoms. In the ninth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ atoms. In the tenth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ atoms. In the eleventh Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ atoms. In the twelfth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ and one Tl1+ atom. In the thirteenth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ atoms. In the fourteenth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ atoms. In the fifteenth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ atoms. In the sixteenth Sb+0.69- site, Sb+0.69- is bonded in a 2-coordinate geometry to two equivalent Co2+ and one Tl1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(V3S4)4 by Materials Project

Tl(V3S4)4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent V+2.58+ sites. In the first V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.32–2.54 Å. In the second V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.33–2.55 Å. In the third V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.32–2.53 Å. In the fourth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.33–2.55 Å. In the fifth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.33–2.55 Å. In the sixth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.33–2.53 Å. In the seventh V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.33–2.55 Å. In the eighth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.33–2.54 Å. In the ninth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.33–2.55 Å. In the tenth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.33–2.54 Å. In the eleventh V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.33–2.54 Å. In the twelfth V+2.58+ site, V+2.58+ is bonded to six S2- atoms to form a mixture of face, edge, and corner-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–S bond distances ranging from 2.33–2.55 Å. Tl1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are three shorter (3.03 Å) and three longer (3.19 Å) Tl–S bond lengths. There are sixteen inequivalent S2- sites. In the first S2- site, S2- is bonded to six V+2.58+ atoms to form distorted face-sharing SV6 pentagonal pyramids. In the second S2- site, S2- is bonded to six V+2.58+ atoms to form distorted face-sharing SV6 pentagonal pyramids. In the third S2- site, S2- is bonded to six V+2.58+ atoms to form distorted face-sharing SV6 pentagonal pyramids. In the fourth S2- site, S2- is bonded to six V+2.58+ atoms to form distorted face-sharing SV6 pentagonal pyramids. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to four V+2.58+ atoms. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the seventh S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the eighth S2- site, S2- is bonded in a 4-coordinate geometry to four V+2.58+ atoms. In the ninth S2- site, S2- is bonded in a 4-coordinate geometry to four V+2.58+ atoms. In the tenth S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the eleventh S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the twelfth S2- site, S2- is bonded in a 4-coordinate geometry to four V+2.58+ atoms. In the thirteenth S2- site, S2- is bonded in a 4-coordinate geometry to four V+2.58+ atoms. In the fourteenth S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the fifteenth S2- site, S2- is bonded in a 5-coordinate geometry to four V+2.58+ and one Tl1+ atom. In the sixteenth S2- site, S2- is bonded in a 4-coordinate geometry to four V+2.58+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

The upgraded summing NaI(Tl) (SuN++) absorption spectrometer

Simulations of astrophysical processes require a plethora of nuclear physics input. In particular, models of neutron-capture nucleosynthesis like the s, i, and r processes require β-decay information and experimentally constrained neutron-capture reaction rates. Past experiments with the 4π Summing NaI(Tl) (SuN) total absorption spectrometer have provided these physics quantities. Here, we outline an upgrade of SuN to SuN++, where 20 new segments (12 NaI(Tl) and 8 CeBr 3 ) have been integrated into the pre-existing SuN total absorption spectrometer to provide increased energy and time resolution in β-decay experiments. The details of the newly upgraded SuN++ total absorption spectrometer are discussed with results from the commissioning experiment at the Facility for Rare Isotope Beams (FRIB) utilizing a 70 Cu beam.

CeBr3↗
DOE OSTI2020

Crystal growth and scintillation properties of pure and Tl-doped Cs 3 Cu 2 I 5

Here, the Bridgman crystal growth and scintillation properties of both undoped and Tl-doped Cs 3 Cu 2 I 5 are presented. This material is very attractive for gamma and X-ray detection applications, with a density of 4.53 g/cm 3 and effective atomic number of 51.9. Undoped Cs 3 Cu 2 I 5 had a light yield of 41,500 photons/MeV, with an energy resolution of 4.4% at 662 keV. Thallium doping at 0.5 mol % resulted in a much-improved scintillation response, in which light yield increased to 98,200 photons/MeV and energy resolution reduced to 3.3% at 662 keV. The X-ray excited emission is centered at 442 nm for the undoped and 500 nm for the Tl-doped crystals. The undoped emission is broad, typical of excitonic emission, while thallium doping results in an even broader band with features of both the undoped and thallium defect-mediated emissions.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Reaction losses of charged particles in CsI(Tl) crystals

To efficiently detect energetic light charged particles, it is common to use arrays of energy-loss telescopes involving two or more layers of detection media. As the energy of the particles increases, thicker layers are usually needed. However, carrying out measurements with thick-telescopes may require corrections for the losses due to nuclear reactions induced by the incident particles on nuclei within the detector and for the scattering of incident particles out of the detector, without depositing their full energy in the active material. In this paper, we develop a method for measuring such corrections and determine the reaction and out-scattering losses for data measured with the silicon-CsI(Tl) telescopes of the newly developed HiRA10 array. Here, the extracted efficiencies are in good agreement with model predictions using the GEANT4 reaction loss algorithm for Z = 1 and Z = 2 isotopes. After correcting for the HiRA10 geometry, we obtain a general function that describes the loss of efficiency due to reaction losses in CsI(Tl) crystals as a function of range.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Enhanced Neutron and γ-Ray Detection via 6 Li Substitution in Undoped and Tl-Doped Zero-Dimensional Perovskite Cs 3 Cu 2 I 5 Scintillators

Radiation detectors are crucial in a wide variety of research and commercial applications, such as oil and gas exploration, medical imaging, nuclear nonproliferation, and homeland security. Neutron and gamma-ray detectors are fundamental components in portal monitors at ports and border crossings, bolstering national security against radiological threats. This study presents a dual-mode scintillator, undoped and Tl-doped 6 Li-Cs 3 Cu 2 I 5 , and demonstrates its potential as a promising material for simultaneous thermal neutron and gamma-ray detection. We explore the Bridgman growth of both undoped and thallium doped Li → Cu and Li → Cs substitutional systems with various Li doping levels and assess their impact on scintillation properties. Under 662 keV gamma-ray excitation, the undoped crystals had light yields up to 35,900 ph/MeV, with energy resolutions down to 4.5%. The Tl-doped crystals performed better than the undoped crystals with light yields peaking at 65,900 ph/MeV and energy resolutions as low as 3.5%. When exposed to a moderated 252 Cf excitation source, our crystals had light yields between 102,900 and 167,200 photons per thermal neutron capture, with a full energy thermal neutron peak reaching 3 MeV in gamma equivalent energy. Pulse shape discrimination studies reveal well-separated gamma and neutron events, resulting in Figure-Of-Merit (FOM) as high as 3.7. Furthermore, these findings highlight the potential of Li-doped Cs 3 Cu 2 I 5 as a viable candidate for next-generation dual-mode scintillators.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

GAMMA SPECTRUM STABILIZATION FOR ENVIRONMENTAL RADIATION MONITORING STATIONS USING NAI(TL) DETECTOR

Abstract Gamma spectrum measured by an NaI(Tl) detector is known to be unstable with the in situ temperature. In the present work, an advanced method has been applied to stabilize the gamma spectrum measured by the NaI(Tl) detector at environmental radiation monitoring (ERM) stations. The method is based on experimental data obtained under controlled conditions in laboratory. In the temperature range from 4 to 45°C, the relative deviation of the peak positions within the stabilized gamma spectrum is less than 2%. To test this method in a real scenario, it has been integrated into the ERM station at the Military Institute of Chemical and Environmental Engineering in Hanoi, Vietnam. The results show that the proposed method is ready for a real application.

Hung, Dinh Tien↗
DOE OSTI2022

Isomers in Tl 203 and core excitations built on a five-nucleon-hole structure

Isomers with three- and five-nucleon-hole configurations have been established in 203 Tl These include newly identified levels with a three-nucleon-hole structure: I π = (15/2 – ) with T 1/2 = 7.9(5) ns and I π = (35/2 – ) with T 1/2 = 4.0(5) ns. In addition, five-nucleon-hole states have also been established: I π = (39/2 – ) with T 1/2 = 1.9(2) ns and I π = (49/2 + ) with T 1/2 = 3.4(4) ns. The previously determined long-lived decay, T 1/2 = 6.6(3) μs from this work, is associated with isomerism of the I π = (29/2 + ) state. Levels above this long-lived isomer have been identified through a delayed-prompt γ–γ coincidence measurement. Five-nucleon-hole states with excitation energies E x ≈ 7 MeV have been established as well as possible octupole excitations of the 208Pb core built on these levels. Furthermore, the level scheme of 203 Tl is extended up to E x ≈ 11 MeV with the inclusion of 25 new transitions. Empirical and shell-model calculations have been performed to aid in the description of the observed states which are found to be of intrinsic character.

190 ≤ A ≤ 219↗
DOE OSTI2020

Particlelike Phonon Propagation Dominates Ultralow Lattice Thermal Conductivity in Crystalline Tl 3 VSe 4

We explore the microscopic mechanisms of ultralow lattice thermal conductivity ($\kappa_{l}$) in Tl$_{3}$VSe$_{4}$~by combining a first-principles density-functional theory (DFT) based framework of anharmonic lattice dynamics with the Peierls-Boltzmann transport equation (PBTE) for phonons. We include contributions of the three- and four-phonon scattering processes to the phonon lifetimes as well as the temperature-dependent anharmonic renormalization of phonon energies arising from an unusually strong quartic anharmonicity in Tl$_{3}$VSe$_{4}$. In contrast to a recent report by Mukhopadhyay~\etal [\textcolor{blue}{Science 360, 1455 (2018)}] which suggested that a significant contribution to $\kappa_{l}$ arises from random walks among uncorrelated oscillators, we show that particle-like propagation of phonon excitations can successfully explain the experimentally observed ultralow $\kappa_{l}$. Our results are also supported by explicit calculations of the off-diagonal terms of the heat-current operator, which are found to be small and indicate that wave-like tunneling of heat-carrying vibrations is of minor importance. Our results (i) resolve the discrepancy between the theoretical and experimental $\kappa_{l}$, (ii) offer new insights into the minimum $\kappa_{l}$ achievable in \TlVSe, and (iii) highlight the importance of high-order anharmonicity in low-$\kappa_{l}$ systems. The methodology demonstrated here may be used to resolve the discrepancies between the experimentally measured and the theoretically calculated $\kappa_{l}$ in skutterides and perovskites, as well as to understand the glasslike $\kappa_{l}$ in complex crystals with strong anharmonicity, leading towards the goal of rational design of new materials.

36 MATERIALS SCIENCE↗