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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Structural, vibrational, thermal, and magnetic properties of mullite-type NdMnTiO 5 ceramic

Mullite-type $R$Mn 2 O 5 ($R$ = Y, rare-earth element) ceramics are of ongoing research attention because of their interesting crystal-chemical and magnetic properties. We report nuclear and magnetic structures of NdMnTiO 5 together with its spectroscopic, thermogravimetric, and magnetic properties. The polycrystalline sample is prepared by solid-state synthesis and characterized from neutron and X-ray powder diffraction data Rietveld refinements. NdMnTiO 5 crystallizes in the orthorhombic space group $Pbam$ with metric parameter $a$ = 755.20(1) pm, $b$ = 869.91(1) pm, $c$ = 582.42(1) pm, and $V$ = 382.62(1) 10 6 pm 3 . The Mn 3+ and Ti 4+ cations are observed to be located in the octahedral and pyramidal sites, respectively. The vibrational features in these polyhedral sites are characterized by Raman and Fourier transform infrared spectroscopes. The higher decomposition temperature of NdMnTiO 5 , compared to other $R$Mn 2 O 5 phases, is explained in terms of the higher bond strength of Ti-O bonds than those of Mn-O bonds. Temperature-dependent DC magnetic susceptibility suggests a paramagnetic to antiferromagnetic phase transition at 43(1) K. Inverse susceptibility in the paramagnetic region above 120 K follows the Curie-Weiss law, resulting in a magnetic moment of 6.33(1) μ B per formula unit. Neutron diffraction data collected at 7.5 K reveal that the magnetic moments of Nd 3+ and Mn 3+ in NdMnTiO 5 are incommensurately ordered with a propagation vector $k$ = (0, 0.238, 0.117).

36 MATERIALS SCIENCE↗
DOE OSTI2021

Spinning no-scale $${\mathcal {F}}$$-SU(5) in the right direction

Abstract The Fermi National Accelerator Laboratory (FNAL) recently announced confirmation of the Brookhaven National Lab (BNL) measurements of the $$g-2$$ g - 2 of the muon that uncovered a discrepancy with the theoretically calculated Standard Model value. We suggest an explanation for the combined BNL+FNAL 4.2 $$\sigma $$ σ deviation within the supersymmetric grand unification theory (GUT) model No-Scale $${\mathcal {F}}$$ F - $$SU(5)$$ S U ( 5 ) supplemented with a string derived TeV-scale extra $$10+\overline{10}$$ 10 + 10 ¯ vector-like multiplet and charged vector-like singlet $$(XE,XE^c)$$ ( X E , X E c ) , dubbed flippons. We introduced these vector-like particles into No-Scale Flipped SU (5) many years ago, and as a result, the renormalization group equation (RGE) running was immediately shaped to produce a distinctive and rather beneficial two-stage gauge coupling unification process to avoid the Landau pole and lift unification to the string scale, in addition to contributing through 1-loop to the light Higgs boson mass. The flippons have long stood ready to tackle another challenge, and now do so yet again, where the charged vector-like “lepton”/singlet couples with the muon, the supersymmetric down-type Higgs $$H_d$$ H d , and a singlet S , using a chirality flip to easily accommodate the muonic $$g-2$$ g - 2 discrepancy in No-Scale $${\mathcal {F}}$$ F - $$SU(5)$$ S U ( 5 ) . Considering the phenomenological success of this string derived model over the prior 11 years that remains accommodative of all presently available LHC limits plus all other experimental constraints, including no fine-tuning, and the fact that for the first time a Starobinsky-like inflationary model consistent with all cosmological data was derived from superstring theory in No-Scale Flipped SU (5), we believe it is imperative to reconcile the BNL+FNAL developments within the model space.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Perform Life Cycle Energy and GHG Emission Analysis, Select Candidate Refrigerant(s), Developing Heat Pump by Using Low-GWP Refrigerants and 5 mm Diameter Tubes

Reducing environmental impacts from the energy conversion systems has been an important research topic due to recent severe global climate changes. In residential buildings, the space heating and cooling are main energy consumers, which are relying on vapor compression based heat pumps. To mitigate the environmental impacts of residential systems, the heat pumps using low-GWP refrigerants and 5mm-tube heat exchangers are proposed to replace the conventional 9 mm or 7 mm tube heat exchangers. This research uses a simulation-based design method to optimize the refrigerant circuitries of a 5-ton low-GWP refrigerant heat pumps whose indoor and outdoor heat exchangers adopt 5 mm tubes. Heat pump systems using four commercially available low-GWP refrigerants (R454A, R454C, ARM20A and ARM20B) are optimized and compared with the baseline R410A system. The results indicate that directly replacing 9 mm tubes into 5mm tubes in the baseline systems induces heat pump performance degradation; by optimizing the 5 mm tube heat pumps with added tube rows, the system refrigerant charge is reduced up to 33% compared with the baseline; the optimized low-GWP 5 mm tube heat pumps offer the same or higher performance under both cooling and heating mode; that under cooling mode, the EER improvement is up to 10.7% and under heating mode the COP improvement is up to 3.4%; and a smart flow control device to maintain counter-flow circuitry pattern on both operating modes can improve the heating performance of 5 mm tube optimized system by up to 3.0%. In an effort to better understand the environmental impacts of these systems, life cycle climate performance (LCCP) evaluation method is used to assess the baseline and optimized systems. LCCP considers the direct and indirect emissions of the system over the course of its lifetime from manufacturing to disposal. Our analyses indicate that the optimized systems using 5mm tubes and low-GWP refrigerants can reduce life-cycle CO 2 emission significantly. And improving system efficiency is the most effective way to reduce the emission of low-GWP refrigerant systems. This report shows that using 5 mm diameter tubes in heat exchangers is a feasible approach to develop heat pumps with low-GWP refrigerants. Using the proposed design approach can yield higher system efficiency with lower environmental impact.

42 ENGINEERING↗
DOE OSTI2024

Characterization of Mn 5 Ge 3 Contacts on a Shallow Ge/SiGe Heterostructure

Mn 5 Ge 3 is a ferromagnetic phase of the Mn-Ge system that is a potential contact material for efficient spin injection and detection. Here, we investigate the creation of Mn 5 Ge 3 -based contacts on a Ge/SiGe quantum well heterostructure via solid-state synthesis. X-ray diffraction spectra fitting indicates the formation of Mn 5 Ge 3 -based contacts on bulk Ge and Ge/SiGe. High-resolution scanning transmission electron microscopy imaging and energy dispersive X-ray spectroscopy verify the correct Mn 5 Ge 3 -based phase formation. Schottky diode measurements, transmission line measurements, and Hall measurements reveal that Mn 5 Ge 3 -based contacts serve as good p-type contacts for Ge/SiGe quantum well heterostructures due to having a low Schottky barrier height of 0.10 eV (extracted from a Mn 5 Ge 3 /n-Ge analogue) and a contact resistance in the order of 1 kΩ. Furthermore, we show that these electrical characteristics have a gate-voltage dependence, thereby providing tunability.

36 MATERIALS SCIENCE↗
DOE OSTI2025

The Importance of Solution Studies for the Structural Characterization of the Enterovirus 5’ Cloverleaf

Enteroviruses initiate genomic replication via a highly conserved mechanism that is controlled by an RNA platform, also known as the 5’ cloverleaf (5’CL). Here, we present a biophysical analysis of the 5’CL conformation of three enterovirus serotypes under various ionic conditions, utilizing CD spectroscopy, size-exclusion chromatography, and small-angle X-ray scattering. In general, a tendency toward a smaller monomeric hydrodynamic radius in the presence of salts was observed, but the exact structural signature of each 5’CL varied depending upon the serotype. Rhinovirus B14 (RVB14) exhibited at least two monomeric conformations and a low propensity for dimerization, while poliovirus 1 (PV1) showed a high propensity for dimerization, which was enhanced by the presence of salts. Enterovirus D70 was observed to be somewhat intermediate, with primarily a monomeric structure, but possessing some potential for dimerization. The equilibrium between the two monomeric and the dimeric conformations is also discussed. These results indicate that the 5’CL conformation may be more complex than the current literature suggests, thus underscoring the need for a combined crystal and solution approach for the accurate representation of the 5’CL conformation, and the conformation of other RNA structural elements, under native conditions.

Virology↗
NASA NTRS1986

The effect of altered 5-hydroxytryptamine levels on beta-endorphin

The purpose of the present study was to examine the effect of altering the concentration of 5-hydroxytryptamine (5-HT) on beta-endorphin (beta-Ep) content in the hypothalamus, thalamus, and periaqueductal gray (PAG)-rostral pons regions of the rat brain. The selective 5-HT reuptake inhibitor, fluoxetine (10 mg/kg), significantly lowered beta-Ep content in the hypothalamus and the PAG. Parachlorophenylalanine, which inhibits 5-HT synthesis, significantly elevated beta-Ep in all brain parts studied. Intracisternal injections of the neurotoxin 5-prime, 7-prime-dihydroxytryptamine with desmethylimipramine pretreatment significantly increased beta-Ep content in the hypothalamus and the PAG. In adrenalectomized rats, fluoxetine significantly decreased beta-Ep levels in the hypothalamus and increased the levels in the PAG. The results indicate that 5-HT may modulate the levels of brain beta-Ep.

Soliman, Karam F. A.↗
NASA NTRS1986

Role of 5-hydroxytryptamine in the regulation of brain neuropeptides in normal and diabetic rat

The effect of 5-hydroxytryptamine (5-HT) alteration on brain dopamine (DA), norepinephrine (NE), beta-endorphin (beta-E), and immunoreactive insulin was studied in Sprague-Dawley diabetic and control rats. Diabetes was induced using alloxan (45 mg/kg), 15 days prior to sacrificing. Both control and diabetic animals were treated with either p-chlorophenylalanine (PCPA, 300 mg/kg) three days prior to sacrificing or fluoxetine (10 mg/kg) twice daily for three days. PCPA treatment significantly decreased brain content of 5-HT and 5-hydroxyindolel acetic acid, while it caused significant increase and decrease in brain beta-E and insulin levels, respectively, in both normal and diabetic rat. Meanwhile, the administration of fluoxetine resulted in significant increase in brain content of 5-HT, DA, NE and insulin but significant decline of beta-E in diabetic and saline control rats. The results of this experiment indicate that 5-HT may be regulating both beta-E and insulin regardless of the availability of pancreatic insulin.

Kolta, Malak G.↗
NASA NTRS1992

Asteroid-type orbit evolution near the 5:2 resonance

In this case of the 5:2 commensurability with the motion of Jupiter, an asteroid can reach the orbits of Mars, Earth, and Venus when eccentricity e is greater than 0.41, 0.65, and 0.74, respectively. For individual fictitious asteroids, Ipatov and Yoshikawa obtained a growth in e from 0.15 to 074-0.76. Rates of changes in orbital orientations are different for Mars, Earth, Venus, and the asteroid. Therefore, for corresponding values of e, the asteroid could encounter these planets and leave the gap at those encounters. In order to investigate this hypothesis of the 5:2 Kirkwood gap formation, Ipatov studied the regions of initial data for which the eccentricities of asteroids located near the 5:2 commensurability exceeded 0.41 during evolution. The orbit evolution for 500 fictitious asteroids was investigated by numerical integration of the complete (unaveraged) equations of motion for the three-body problem (Sun-Jupiter-asteroid). The equations of motion were integrated in the time intervals T is greater than or equal to 5(10)(exp 3)t(sub J) (t(sub J) is the heliocentric orbital period of Jupiter) in the planar model, T is greater than or equal to 10(exp 4)t(sub J) at initial inclination 5 deg is less than or equal to i(sub 0) is less than or equal to 20 deg and T = 10(exp 5)t(sub J) at i(sub 0) = 40 deg. The larger interval T was taken at i(sub 0) = 40 deg because in this case for the majority of runs maximum values of e and i were reached in the time delta(t) is greater than 2(10)(exp 4)t(sub J).

Ipatov, S. I.↗
NASA NTRS1994

Spectral and correlated timing behaviour of GX 5-1

We have analyzed the X-ray spectral and fast timing behavior of the Z-source GX 5-1 using X-ray color-color diagrams (CDs), hardness-intensity diagrams (HIDs) and power spectra. We used all EXOSAT ME data on GX 5-1, a total of seven observations during 1983-1985. We detect, for the first time in GX 5-1, secular motion of the well-known 'Z' pattern through the CDs and HIDs. This behavior resembles Cyg X-2, but in GX 5-1 has a smaller amplitude. We find that the power spectra do not change when the 'Z' moves, and are only dependent on the position inside the 'Z'. We also report, for the first time in GX 5-1, indications of flaring-branch (FB) like behavior, both during one of our EXOSAT observations, and during observations done with Ginga. As the secular changes of the position of the 'Z' pattern in the CD and HID are relatively small we investigated in detail the systematic changes in the EXOSAT ME detectors using the only bright and steady X-ray 'standard star', the Crab Nebula. Finally, we determined an intrinsic CD of GX 5-1 (i.e. a soft photon flux-ratio versus hard photon flux-ratio diagram) in a model independent way, by applying a first order correction for the detector efficiency. It is shown, using data of the Crab Nebula, that this method works reasonably well for the determination of intrinsic colors.

Kuulkers, E.↗
NASA NTRS2007

The UDF05 Follow-up of the HUDF: I. The Faint-End Slope of the Lyman-Break Galaxy Population at zeta approx. 5

We present the UDF05 project, a HST Large Program of deep ACS (F606W, F775W, F850LP, and NICMOS (Fll0W, Fl60W) imaging of three fields, two of which coincide with the NICP1-4 NICMOS parallel observations of the Hubble Ultra Deep Field (HUDF). In this first paper we use the ACS data for the NICP12 field, as well as the original HUDF ACS data, to measure the UV Luminosity Function (LF) of z approximately 5 Lyman Break Galaxies (LBGs) down to very faint levels. Specifically, based on a V - i, i - z selection criterion, we identify a sample of 101 and 133 candidate z approximately 5 galaxies down to z(sub 850) = 28.5 and 29.25 magnitudes in the NICP12 field and in the HUDF, respectively. Using an extensive set of Monte Carlo simulations we derive corrections for observational biases and selection effects, and construct the rest-frame 1400 Angstroms LBG LF over the range M(sub 1400) = [-22.2, -17.1], i.e. down to approximately 0.04 L(sub *) at z = 5. We show that: (i) Different assumptions for the SED distribution of the LBG population, dust properties and intergalactic absorption result in a 25% variation in the number density of LBGs at z = 5 (ii) Under consistent assumptions for dust properties and intergalactic absorption, the HUDF is about 30% under-dense in z = 5 LBGs relative to the NICP12 field, a variation which is well explained by cosmic variance; (iii) The faint-end slope of the LF is independent of the specific assumptions for the input physical parameters, and has a value of alpha approximately -1.6, similar to the faint-end slope of the LF that has been measured for LBGs at z = 3 and z = 6. Our study therefore supports no variation in the faint-end of the LBG LF over the whole redshift range z = 3 to z = 6. The comparison with theoretical predictions suggests that (a,) the majority of the stars in the z = 5 LBG population are produced with a Top-Heavy IMF in merger-driven starbursts, and that (b) possibly, either the fraction of stellar mass produced in starburst, or the fraction of high mass stars in the bursts is increased towards the bright end of the LF.

Oesch, P. A.↗
NASA NTRS2018

The Salinity Retrieval Algorithms for the NASA Aquarius Version 5 and SMAP Version 3 Releases

The Aquarius end-of-mission (Version 5) salinity data set was released in December 2017. This article gives a comprehensive overview of the main steps of the Level 2 salinity retrieval algorithm. In particular, we will discuss the corrections for wind induced surface roughness, atmospheric oxygen absorption, reflected galactic radiation and side-lobe intrusion from land surfaces. Most of these corrections have undergone major updates from previous versions, which has helped mitigating temporal and zonal biases. Our article also discusses the ocean target calibration for Aquarius Version 5. We show how formal error estimates for the Aquarius retrievals can be obtained by perturbing the input to the algorithm. The performance of the Aquarius Version 5 salinity retrievals is evaluated against salinity measurements from the ARGO network and the HYCOM model. When stratified as function of sea surface temperature or sea surface wind speed, the difference between Aquarius Version 5 and ARGO is within +/-0.1 psu. The estimated global RMS uncertainty for monthly 100 km averages is 0.128 psu for the Aquarius Version 5 retrievals. Finally, we show how the Aquarius Version 5 salinity retrieval algorithm is adapted to retrieve salinity from the Soil-Moisture Active Passion (SMAP) mission.

retrieval algorithm↗
NASA NTRS2018

The Salinity Retrieval Algorithms for the NASA Aquarius Version 5 and SMAP Version 3 Releases

The Aquarius end-of-mission (Version 5) salinity data set was released in December 2017. This article gives a comprehensive overview of the main steps of the Level 2 salinity retrieval algorithm. In particular, we will discuss the corrections for wind induced surface roughness, atmospheric oxygen absorption, reflected galactic radiation and side-lobe intrusion from land surfaces. Most of these corrections have undergone major updates from previous versions, which has helped mitigating temporal and zonal biases. Our article also discusses the ocean target calibration for Aquarius Version 5. We show how formal error estimates for the Aquarius retrievals can be obtained by perturbing the input to the algorithm. The performance of the Aquarius Version 5 salinity retrievals is evaluated against salinity measurements from the ARGO network and the HYCOM model. When stratified as function of sea surface temperature or sea surface wind speed, the difference between Aquarius Version 5 and ARGO is within +-0.1 psu. The estimated global RMS uncertainty for monthly 100 km averages is 0.128 psu for the Aquarius Version 5 retrievals. Finally, we show how the Aquarius Version 5 salinity retrieval algorithm is adapted to retrieve salinity from the Soil-Moisture Active Passion (SMAP) mission.

calibration↗
DOE OSTI2020

Materials Data on Ba3Sr5Co3(CuO4)5 by Materials Project

Ba3Sr5Co3(CuO4)5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.75–3.10 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–2.93 Å. In the third Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–2.92 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.74–2.93 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–3.03 Å. In the sixth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–2.98 Å. In the seventh Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–3.01 Å. In the eighth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.73–2.92 Å. In the ninth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–2.96 Å. In the tenth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–2.95 Å. In the eleventh Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.74–2.95 Å. In the twelfth Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.68–3.20 Å. There are twenty inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.22 Å. In the second Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.57–2.95 Å. In the third Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–3.03 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.51–3.10 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–3.00 Å. In the sixth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.52–2.99 Å. In the seventh Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.08 Å. In the eighth Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–3.25 Å. In the ninth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.52–2.90 Å. In the tenth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.50–3.04 Å. In the eleventh Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.52–3.07 Å. In the twelfth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.54–3.05 Å. In the thirteenth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.50–3.07 Å. In the fourteenth Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–3.16 Å. In the fifteenth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.01 Å. In the sixteenth Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.54–3.23 Å. In the seventeenth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.52–3.06 Å. In the eighteenth Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.58–3.26 Å. In the nineteenth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–2.87 Å. In the twentieth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.05 Å. There are twelve inequivalent Co4+ sites. In the first Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one CoO6 octahedra, a cornercorner with one CuO6 octahedra, corners with two CoO5 square pyramids, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 2–4°. There are a spread of Co–O bond distances ranging from 1.83–2.35 Å. In the second Co4+ site, Co4+ is bonded to five O2- atoms to form distorted CoO5 square pyramids that share a cornercorner with one CoO6 octahedra, a cornercorner with one CuO6 octahedra, corners with two CoO5 square pyramids, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 3–8°. There are a spread of Co–O bond distances ranging from 1.82–2.27 Å. In the third Co4+ site, Co4+ is bonded to five O2- atoms to form distorted CoO5 square pyramids that share a cornercorner with one CoO6 octahedra, a cornercorner with one CuO6 octahedra, corners with two CoO5 square pyramids, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 4–7°. There are a spread of Co–O bond distances ranging from 1.83–2.20 Å. In the fourth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with three CoO6 octahedra, and a cornercorner with one CuO4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–7°. There are a spread of Co–O bond distances ranging from 1.88–2.19 Å. In the fifth Co4+ site, Co4+ is bonded to five O2- atoms to form distorted CoO5 square pyramids that share a cornercorner with one CoO6 octahedra, a cornercorner with one CuO6 octahedra, corners with two CoO5 square pyramids, and a cornercorner with one CuO4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–10°. There are a spread of Co–O bond distances ranging from 1.83–2.19 Å. In the sixth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with three CoO6 octahedra, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 2–8°. There are a spread of Co–O bond distances ranging from 1.86–2.28 Å. In the seventh Co4+ site, Co4+ is bonded to five O2- atoms to form distorted CoO5 square pyramids that share a cornercorner with one CoO6 octahedra, corners with three CoO5 square pyramids, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 8°. There are a spread of Co–O bond distances ranging from 1.83–2.15 Å. In the eighth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two CoO6 octahedra, corners with two CuO6 octahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 5–6°. There are a spread of Co–O bond distances ranging from 1.87–2.19 Å. In the ninth Co4+ site, Co4+ is bonded to five O2- atoms to form CoO5 square pyramids that share a cornercorner with one CoO6 octahedra, corners with three CoO5 square pyramids, and a cornercorner with one CuO4 tetrahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Co–O bond distances ranging from 1.83–2.15 Å. In the tenth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two CoO6 octahedra, corners with two CuO6 octahedra, and corners with two CuO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 5–8°. There are a spread of Co–O bond distances ranging from 1.86–2.19 Å. In the eleventh Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one CoO6 octahedra, corners with three CoO5 square pyramids, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 4°. There are a spread of Co–O bond distances ranging from 1.80–2.38 Å. In the twelfth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two CoO6 octahedra, corners with two CuO6 octahedra, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Co–O bond distances ranging from 1.88–2.31 Å. There are twenty inequivalent Cu+2.40+ sites. In the first Cu+2.40+ site, Cu+2.40+ is bonded to six O2- atoms to form CuO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with three CoO6 octahedra, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 5–8°. There are a spread of Cu–O bond distances ranging from 1.96–2.36 Å. In the second Cu+2.40+ site, Cu+2.40+ is bonded to six O2- atoms to form CuO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with three CoO6 octahedra, and corners with two CuO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Cu–O bond distances ranging from 2.01–2.14 Å. In the third Cu+2.40+ site, Cu+2.40+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share a cornercorner with one CoO6 octahedra, corners with three CoO5 square pyramids, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 2°. There are a spread of Cu–O bond distances ranging from 1.95–2.60 Å. In the fourth Cu+2.40+ site, Cu+2.40+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with two CoO6 octahedra, corners with two CuO6 octahedra, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 2–5°. There are a spread of Cu–O bond distances ranging from 1.96–2.32 Å. In the fifth Cu+2.40+ site, Cu+2.40+ is bonded to four O2- atoms to form CuO4 trigonal pyramids that share a cornercorner with one CoO6 octahedra, a cornercorner with one CuO6 octahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 12–21°. There are a spread of Cu–O bond distances ranging from 1.84–1.91 Å. In the sixth Cu+2.40+ site, Cu+2.40+ is bonded to four O2- atoms to form CuO4 tetrahedra that share corners with two CuO6 octahedra, a cornercorner with one CuO4 tetrahedra, and a cornercorner with one CuO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 18–21°. There are a spread of Cu–O bond distances ranging from 1.84–1.92 Å. In the seventh Cu+2.40+

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca8Al3(FeO4)5 by Materials Project

Ca8Al3(FeO4)5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.85 Å. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.92 Å. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.84 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.91 Å. In the fifth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.87 Å. In the sixth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.97 Å. In the seventh Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.98 Å. In the eighth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.86 Å. There are five inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four AlO6 octahedra and corners with two FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 11–12°. There are a spread of Fe–O bond distances ranging from 1.98–2.15 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one AlO6 octahedra, and corners with two FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–38°. There are a spread of Fe–O bond distances ranging from 1.87–1.96 Å. In the third Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with two AlO6 octahedra and corners with two FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–34°. There are a spread of Fe–O bond distances ranging from 1.88–1.96 Å. In the fourth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one AlO6 octahedra, and corners with two FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–38°. There are a spread of Fe–O bond distances ranging from 1.86–1.96 Å. In the fifth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with two AlO6 octahedra and corners with two FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–34°. There are a spread of Fe–O bond distances ranging from 1.88–1.96 Å. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and corners with two FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 10–12°. There are a spread of Al–O bond distances ranging from 1.90–2.06 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and corners with two FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 10–12°. There are a spread of Al–O bond distances ranging from 1.88–2.07 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four AlO6 octahedra and corners with two FeO4 tetrahedra. The corner-sharing octahedral tilt angles are 10°. There are a spread of Al–O bond distances ranging from 1.90–2.05 Å. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Fe3+, and one Al3+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+, one Fe3+, and one Al3+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+, one Fe3+, and one Al3+ atom. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Fe3+, and one Al3+ atom. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Fe3+, and one Al3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and two Fe3+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Fe3+, and one Al3+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and two Fe3+ atoms. In the ninth O2- site, O2- is bonded to four Ca2+ and two Al3+ atoms to form distorted OCa4Al2 octahedra that share a cornercorner with one OCa4Al2 octahedra, corners with four OCa2Fe2 tetrahedra, an edgeedge with one OCa4Al2 octahedra, and faces with three OCa4Al2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the tenth O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+, one Fe3+, and one Al3+ atom. In the eleventh O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+, one Fe3+, and one Al3+ atom. In the twelfth O2- site, O2- is bonded to four Ca2+ and two Al3+ atoms to form distorted OCa4Al2 octahedra that share a cornercorner with one OCa4Al2 octahedra, corners with four OCa2Fe2 tetrahedra, an edgeedge with one OCa4Al2 octahedra, and faces with three OCa4Al2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the thirteenth O2- site, O2- is bonded to four Ca2+ and two Al3+ atoms to form distorted OCa4Al2 octahedra that share a cornercorner with one OCa4Al2 octahedra, corners with four OCa2Fe2 tetrahedra, an edgeedge with one OCa4Al2 octahedra, and faces with three OCa4Al2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the fourteenth O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+, one Fe3+, and one Al3+ atom. In the fifteenth O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+, one Fe3+, and one Al3+ atom. In the sixteenth O2- site, O2- is bonded to four Ca2+ and two Al3+ atoms to form distorted OCa4Al2 octahedra that share a cornercorner with one OCa4Al2 octahedra, corners with four OCa2Fe2 tetrahedra, an edgeedge with one OCa4Al2 octahedra, and faces with three OCa4Al2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the seventeenth O2- site, O2- is bonded to two Ca2+ and two Fe3+ atoms to form distorted OCa2Fe2 tetrahedra that share corners with six OCa4Al2 octahedra and corners with two OCa2Fe2 tetrahedra. The corner-sharing octahedra tilt angles range from 24–77°. In the eighteenth O2- site, O2- is bonded to two Ca2+ and two Fe3+ atoms to form distorted OCa2Fe2 tetrahedra that share corners with two OCa4Al2 octahedra and corners with two OCa2Fe2 tetrahedra. The corner-sharing octahedra tilt angles range from 23–62°. In the nineteenth O2- site, O2- is bonded to two Ca2+ and two Fe3+ atoms to form distorted OCa2Fe2 tetrahedra that share corners with six OCa4Al2 octahedra and corners with two OCa2Fe2 tetrahedra. The corner-sharing octahedra tilt angles range from 23–77°. In the twentieth O2- site, O2- is bonded to two Ca2+ and two Fe3+ atoms to form distorted OCa2Fe2 tetrahedra that share corners with two OCa4Al2 octahedra and corners with two OCa2Fe2 tetrahedra. The corner-sharing octahedra tilt angles range from 48–77°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na26(Ge3Au8)5 by Materials Project

Na26(Au8Ge3)5 is alpha-derived structured and crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. there are eleven inequivalent Na sites. In the first Na site, Na is bonded in a 12-coordinate geometry to three Na, nine Au, and three Ge atoms. There are a spread of Na–Na bond distances ranging from 3.06–3.56 Å. There are a spread of Na–Au bond distances ranging from 3.10–3.36 Å. There are a spread of Na–Ge bond distances ranging from 3.27–3.35 Å. In the second Na site, Na is bonded in a 12-coordinate geometry to two Na, nine Au, and three Ge atoms. The Na–Na bond length is 3.46 Å. There are a spread of Na–Au bond distances ranging from 3.09–3.38 Å. There are a spread of Na–Ge bond distances ranging from 3.27–3.38 Å. In the third Na site, Na is bonded in a 10-coordinate geometry to two equivalent Na, ten Au, and three Ge atoms. Both Na–Na bond lengths are 3.06 Å. There are a spread of Na–Au bond distances ranging from 3.10–3.21 Å. There are a spread of Na–Ge bond distances ranging from 3.19–3.27 Å. In the fourth Na site, Na is bonded in a 4-coordinate geometry to nine Au and four Ge atoms. There are a spread of Na–Au bond distances ranging from 3.08–3.27 Å. There are two shorter (3.11 Å) and two longer (3.27 Å) Na–Ge bond lengths. In the fifth Na site, Na is bonded in a 11-coordinate geometry to two equivalent Na, eight Au, and five Ge atoms. Both Na–Na bond lengths are 3.16 Å. There are four shorter (3.10 Å) and four longer (3.17 Å) Na–Au bond lengths. There are a spread of Na–Ge bond distances ranging from 3.10–3.18 Å. In the sixth Na site, Na is bonded in a 11-coordinate geometry to two Na, ten Au, and three Ge atoms. Both Na–Na bond lengths are 3.00 Å. There are a spread of Na–Au bond distances ranging from 3.10–3.33 Å. There are one shorter (3.18 Å) and two longer (3.41 Å) Na–Ge bond lengths. In the seventh Na site, Na is bonded in a 5-coordinate geometry to four Na, nine Au, and three Ge atoms. The Na–Na bond length is 3.31 Å. There are a spread of Na–Au bond distances ranging from 3.13–3.53 Å. There are one shorter (3.26 Å) and two longer (3.35 Å) Na–Ge bond lengths. In the eighth Na site, Na is bonded in a 5-coordinate geometry to one Na, nine Au, and two equivalent Ge atoms. There are a spread of Na–Au bond distances ranging from 3.13–3.50 Å. Both Na–Ge bond lengths are 3.41 Å. In the ninth Na site, Na is bonded in a 5-coordinate geometry to four Na, eight Au, and four Ge atoms. The Na–Na bond length is 3.49 Å. There are a spread of Na–Au bond distances ranging from 3.10–3.49 Å. There are a spread of Na–Ge bond distances ranging from 3.25–3.58 Å. In the tenth Na site, Na is bonded in a 5-coordinate geometry to one Na, seven Au, and three Ge atoms. There are a spread of Na–Au bond distances ranging from 3.08–3.28 Å. There are one shorter (3.27 Å) and two longer (3.37 Å) Na–Ge bond lengths. In the eleventh Na site, Na is bonded in a 7-coordinate geometry to seven Au and three Ge atoms. There are a spread of Na–Au bond distances ranging from 3.09–3.25 Å. There are one shorter (3.36 Å) and two longer (3.37 Å) Na–Ge bond lengths. There are fourteen inequivalent Au sites. In the first Au site, Au is bonded in a 12-coordinate geometry to five Na, one Au, and one Ge atom. The Au–Au bond length is 2.87 Å. The Au–Ge bond length is 2.55 Å. In the second Au site, Au is bonded in a 12-coordinate geometry to five Na, one Au, and one Ge atom. The Au–Au bond length is 2.88 Å. The Au–Ge bond length is 2.56 Å. In the third Au site, Au is bonded in a 1-coordinate geometry to five Na, one Au, and one Ge atom. The Au–Au bond length is 2.88 Å. The Au–Ge bond length is 2.53 Å. In the fourth Au site, Au is bonded in a 12-coordinate geometry to five Na, one Au, and one Ge atom. The Au–Au bond length is 2.90 Å. The Au–Ge bond length is 2.55 Å. In the fifth Au site, Au is bonded in a 1-coordinate geometry to five Na, one Au, and one Ge atom. The Au–Au bond length is 2.92 Å. The Au–Ge bond length is 2.55 Å. In the sixth Au site, Au is bonded to twelve Au atoms to form AuAu12 cuboctahedra that share corners with two equivalent GeNa6Au6 cuboctahedra. In the seventh Au site, Au is bonded in a 12-coordinate geometry to six Na, three Au, and three Ge atoms. There are one shorter (2.82 Å) and two longer (2.89 Å) Au–Au bond lengths. There are a spread of Au–Ge bond distances ranging from 2.61–2.96 Å. In the eighth Au site, Au is bonded in a 12-coordinate geometry to six Na, four Au, and two Ge atoms. There are a spread of Au–Au bond distances ranging from 2.82–3.09 Å. There are one shorter (2.59 Å) and one longer (2.82 Å) Au–Ge bond lengths. In the ninth Au site, Au is bonded in a 12-coordinate geometry to six Na, three Au, and three Ge atoms. There are one shorter (2.90 Å) and one longer (2.91 Å) Au–Au bond lengths. There are a spread of Au–Ge bond distances ranging from 2.59–2.90 Å. In the tenth Au site, Au is bonded in a 12-coordinate geometry to six Na, three Au, and three Ge atoms. There are one shorter (2.91 Å) and one longer (2.95 Å) Au–Au bond lengths. There are a spread of Au–Ge bond distances ranging from 2.60–2.88 Å. In the eleventh Au site, Au is bonded in a 12-coordinate geometry to six Na, four Au, and two Ge atoms. There are one shorter (2.90 Å) and one longer (3.02 Å) Au–Au bond lengths. There are one shorter (2.55 Å) and one longer (2.68 Å) Au–Ge bond lengths. In the twelfth Au site, Au is bonded in a 12-coordinate geometry to six Na, four Au, and two Ge atoms. The Au–Au bond length is 3.08 Å. There are one shorter (2.56 Å) and one longer (2.64 Å) Au–Ge bond lengths. In the thirteenth Au site, Au is bonded in a 3-coordinate geometry to seven Na, five Au, and two Ge atoms. The Au–Au bond length is 2.75 Å. There are one shorter (3.16 Å) and one longer (3.21 Å) Au–Ge bond lengths. In the fourteenth Au site, Au is bonded in a 1-coordinate geometry to seven Na, four equivalent Au, and one Ge atom. The Au–Ge bond length is 2.49 Å. There are seven inequivalent Ge sites. In the first Ge site, Ge is bonded in a 11-coordinate geometry to six Na and five Au atoms. In the second Ge site, Ge is bonded in a 12-coordinate geometry to five Na and five Au atoms. In the third Ge site, Ge is bonded in a 11-coordinate geometry to six Na and five Au atoms. In the fourth Ge site, Ge is bonded in a 12-coordinate geometry to six Na and six Au atoms. In the fifth Ge site, Ge is bonded to six Na and six Au atoms to form distorted GeNa6Au6 cuboctahedra that share a cornercorner with one AuAu12 cuboctahedra and an edgeedge with one GeNa6Au6 cuboctahedra. In the sixth Ge site, Ge is bonded in a 1-coordinate geometry to seven Na and five Au atoms. In the seventh Ge site, Ge is bonded in a 12-coordinate geometry to three Na, four Au, and one Ge atom. The Ge–Ge bond length is 2.70 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Indium segregation in Gd 5 (Si, Ge) 4 magnetocaloric materials

Chemical substitution is one of the most efficient tools to tune and optimize magnetic and magnetocaloric properties of the giant magnetocaloric materials. In particular, Indium substitutions could be useful both for tuning properties of these interesting intermetallic materials and to unveil their local-scale behavior across the magnetostructural transition via hyperfine techniques. Hence, in order to investigate the effect of Indium additions on the crystal structure, micro-structure, magnetic and magnetocaloric properties, a series of In-containing samples derived from the base Gd 5 Si 1.2 Ge 2.8 stoichiometry were prepared. Here, the major findings are that while In is insoluble in the 5:4 phase, it will instead promote the emergence of the impurity 5:3 phase and segregates into this phase. Hence, In leads to major crystallographic changes, which enhance atomic disorder and disrupt the Si to Ge ratio in the 5:4 phase. Subsequently, a higher 5:4 unit cell volume and a lower magnetic ordering temperature are found in the In-substituted samples. Finally, the magnetocaloric properties of the In-substituted samples reveal a detrimental effect on the maximum magnetic entropy change.

36 MATERIALS SCIENCE↗
DOE OSTI2020

TlSr 2 I 5 :Eu 2+ - A new high density scintillator for gamma-ray detection

In this paper we report on the scintillation properties of TlSr 2 I 5 doped with Eu 2+ , a novel thallium-containing high-resolution scintillator for gamma-ray spectroscopy. Here, small diameter, good quality crystals of TlSr 2 I 5 :Eu (TSI) with different Eu 2+ concentrations were grown by the vertical Bridgman method. X-ray diffraction measurements show that single crystals of TSI belong to the monoclinic system with space group P2 1 /c. TlSr 2 I 5 has a density of 5.32 g/cm 3 and effective Z of 60. The X-ray excited emission of Eu 2+ doped TlSr 2 I 5 features a broad emission band peaking between 460–470 nm. The light yield of TlSr 2 I 5 crystal doped with 1% Eu 2+ is measured to be ~72,000 ph/MeV with an energy resolution of 2.8% at 662 keV. The scintillation decay time which is characteristic of Eu 2+ shows two components, with 90% of the light in a ~500 ns component and the rest in a longer component of ~3 μs.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Polarizing 3 He via metastability exchange optical pumping using a 1.2 mbar sealed cell at magnetic fields up to 5 T

Here, we report high nuclear polarization of 1.2 mbar 3 He gas in a sealed cell in magnetic fields up to 5 T using Metastability Exchange Optical Pumping (MEOP). The creation of a highly polarized 3 He gas target for use in the 5 T field of Jefferson Lab’s CLAS12 spectrometer would enable new studies of spin-dependent asymmetries on the neutron. We describe a systematic study which was conducted for the first time up to the full 5 T field required for the final target design to evaluate the effects of discharge intensity, pump laser power, and optical pumping transition schemes on nuclear polarization and pumping rates. Steady-state polarizations up to 86% in magnetic fields between 2 and 5 T were achieved, with a discharge-on relaxation time of 898 s at 5 T. These results underscore the potential of MEOP for high-field applications in nuclear physics experiments.

3He polarization↗