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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Quench Simulation and Validation for EIC Direct Wind Magnets

The Electron-Ion Collider (EIC), a new facility to be built in the United States at the U.S. Department of Energy’s Brookhaven National Laboratory in collaboration with Thomas Jefferson National Accelerator Facility-will be the only new particle collider in the U.S. for the next 10∼20 years. The EIC project will investigate the origin of mass and building blocks of the Universe. It will accelerate and collide beams of electrons with protons and nuclei. Unlike any collider that has ever existed before, both EIC’s particle beams will be polarized, meaning their spins will be aligned in a controlled way to allow for precision measurements. Different types of new superconducting magnets will be required near the interaction region (IR) of EIC. A 6-around-1 NbTi cable will be used for some of those new superconducting magnets. Given the relatively smaller conductors used for those direct wind magnets, the overall engineering current density will be 2–3 times higher in comparison to traditional collared superconducting magnets in other accelerator magnets. This is technically challenging and potentially represents high risks for quench protection. Here, in this paper we use different tools and methods for quench simulation for several EIC direct wind magnets. We also present results of a sensitivity study, exploring different material properties and Jc curves. This paper also discusses and validates the quench simulation results with measurement results from a small-scale serpentine magnet tested at BNL in October 2024.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Proton Quenching in Rare-Earth Inorganic Scintillators: GAGG:Ce and YSO:Ce

Scintillator detectors are an integral component of radiation detection systems for a variety of applications such as medical imaging, accelerator diagnostics, and space science. Typically, a scintillator detector’s response is characterized using gamma sources to understand the detection response to different types of radiation, including charged particle detection. However, there exists a nonlinearity of the amount of light produced from an incident gamma ray of specific energy and the light produced from an incident charged particle of the same energy. This important effect, known as quenching, must be accounted for to interpret energies from charged particles incident on detectors. In this article, we present results of quenching parameterization for two types of cerium-doped inorganic scintillators, Y2SiO5:Ce (YSO:Ce) and Gd3Al2Ga3O12:Ce (GAGG:Ce). We measured the light output from incident proton energies from 1 to 25 MeV using a 3-MV tandem accelerator and two reactions: Au(p,p)Au and 3He(d,p)⁴He. Using gamma-ray sources to calibrate the detectors, we compared the measured electron-equivalent energy versus the incident energy expected. Using an adaptation of the Birks semi-empirical formula, we extracted the Birks parameter (kB) to understand quenching. For one of the GAGG:Ce samples, the kB parameter of 0.0072 [g cm-2 MeV-1] is comparable to a similar study where the value of kB was 0.0065 [g cm-2 MeV-1]. For YSO:Ce, no other kB values were found in the literature. Three different types of GAGG:Ce were used to collect measurements of kB as a function of dopant concentration.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRSDate not supplied

Extinction of Solid Diffusion Flame in Microgravity: Details of Quenching and Blowoff Processes

Long duration microgravity experiments aboard the International Space Station determine diffusion flame extinction limits of PMMA spheres. Upon ignition from an electrically-heated coil, the 4-cm-diameter samples are exposed to forced flows ranging from 0.2 to 80 cm/s and an oxygen ranging from 13 to 28% in one atmosphere total pressure. Extinction is reached as oxygen concentration gradually decreases by natural depletion. Five extinction tests are presented at different flow velocities and oxygen concentrations. Quenching at low velocity is observed with the flame tip shrinking upstream and blowoff is observed when a hole forms in the flame at the forward flow stagnation point. However, these processes are not quasistatic. The quenching motion involves periodic flame tip pulsating toward downstream and shrinking upstream with a continually decreasing flame size at the end of each cycle. In blowoff, the flame base pulsates between the flame hole and the downstream location, although with far fewer cycles compared to quenching. The pulsations appear to be the result of a premixed flame front spreading into a combustible mixture. Two specific cases are discussed. In the first, at very low flow velocity (~ 0.4 cm/s) and elevated oxygen, self-sustained flame tip cyclic pulsations are observed for a lengthy period (~15 minutes). In the second case with a higher flow velocity (50 cm/s), the diffusion flame is stabilized at the shoulder of the spherical sample after local stagnation point blowoff. With steady decrease in ambient oxygen due to depletion, spinning flamelets are formed. The long-duration microgravity environment makes it possible to observe. these interesting and detailed extinction processes.

Flame quenching↗
DOE OSTI2025

Self‐Trapped Hole Migration and Defect‐Mediated Thermal Quenching of Luminescence in α‐ and β‐Ga 2 O 3

Gallium oxide (Ga 2 O 3 ) is a promising ultrawide bandgap semiconductor for next-generation power electronics and optoelectronic devices. Here, temperature-dependent and polarization-resolved photoluminescence excitation spectroscopy data, complemented by hybrid-functional first-principles calculations, are presented, and a microscopic model is derived that explains the interplay of hole migration, defect trapping, and carrier recombination at defects underlying thermal quenching phenomena in α- and β-Ga 2 O 3 . In α-Ga 2 O 3 , the UV emission is attributed to self-trapped holes, while the blue luminescence arises from defect-related processes, including gallium split vacancies and their defect complexes. Calculations reveal an energy barrier of 88 meV for self-trapped hole migration in α-Ga 2 O 3 , consistent with activation energies from temperature-dependent photoluminescence. This enables efficient trapping by defects, enhancing blue luminescence and quenching UV emission. In β-Ga 2 O 3 , a higher migration barrier of 0.36 eV reduces the defect trapping, allowing the UV self-trapped hole emission to remain intense, with blue luminescence emerging only at elevated temperatures. These results establish a direct link between self-trapped hole migration, defect trapping, and thermal quenching of emission in both phases. The insights advance the understanding of carrier dynamics in ultrawide bandgap oxides and may guide defect engineering for high-performance functional devices.

Hajizadeh, Nima [Leibniz-Institut im Forschungsver↗
DOE OSTI2025

Non-linear dynamics of jet quenching

We develop a comprehensive analytic framework for jet quenching in QCD media, based on a medium-induced parton cascade sourced by collinear virtual splittings. We show that the energy flow out of the jet cone, driven by turbulent gluon cascades, is governed by a non-linear rate equation that resums gluon splittings at arbitrary angles and is enhanced by the medium length, L. The solution of this equation sets the initial condition for a non-linear DGLAP-like evolution equation, which describes the collinear early vacuum cascade resolved by the medium at angles exceeding the medium resolution angle, θ c . For asymptotic jet energies, the medium-induced cascade displays an exponential behavior that generalizes the Poisson-like distribution of parton energy loss. This formulation enables the resummation of leading contributions in α s ln(1/R), and α s ln(R/θ c ), and powers of α s L. We briefly explore the limit of strong quenching, where analytic treatments are feasible, offering insights into the impact of parton cascades on jet quenching. These results provide guidance for future numerical simulations and analytical investigations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Crystallographic stability of the BCC phase during quenching of metastable beta titanium alloy Ti-5553 and comparison of structural criteria for the predictive capability of α” martensite

This work evaluates the compositional standard currently developed for Ti-5553 powder and explores the metastable β region for sensitivity to martensitic formation during rapid quenching from the melt. Ti-5553 is a beta-stabilized titanium alloy that is increasingly being used in additive manufacturing applications. A series of alloys within the Ti-5553 compositional space was processed using two-piston spat quenching to perform rapid solidification and quenching for each of these alloy compositions. Typical empirical models such as molybdenum equivalency are not able to fully separate the retained BCC and martensitic compositions. Further, the use of thermodynamic data to estimate the transformation energy needed to form martensite can differentiate the alloys and provide a metric to further develop compositional limits for metastable beta titanium alloy development.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Uranyl fluorescence in acidic solution: quenching effects by tetramethylammonium (TMA + )

The quenching of uranyl luminescence by various cation species was studied in aqueous media at low pH. Solutions with different nitrate salts, held at constant uranyl nitrate, nitric acid, and ion concentration, were tested to examine the quenching effects of the cations from the nitrate salts. Alkali metal (Li + , Na + , Rb + ) and quaternary ammonium cations (NH 4 + ), (CH 3 ) 4 N + (TMA + ), (C 2 H 5 ) 4 N + (TEA + ) were investigated. Solutions containing TMA + reduced the lifetime of uranyl fluorescence significantly more than the other cations. Uranyl emission spectra also showed that TMA + increased the complex formation between uranyl and nitrate ions. Fluorescence decay lifetime measurements for most solutions yielded values between 1.4–1.9 μs at 20 °C, while 1.8 M TMA + reduced the lifetime of uranyl fluorescence to 0.6 μs. Decay rate versus concentration data (Stern–Volmer plots) indicated a dynamic quenching process with increasing fluorescence decay rates at higher cation concentrations for Li + , TMA + , and TEA + . The temperature dependencies of the decay rates and the kinetics in D 2 O were also examined.

Persinger, Thomas D. [Argonne National Laboratory ↗
DOE OSTI2026

Quench Propagation On Rare-Earth Barium Copper Oxide (REBCO) Tape

Rare Earth Barium Copper Oxide (REBCO) is a high‑temperature superconducting material that has zero electrical resistance. A quench occurs when a section of the superconductor suddenly transitions to a resistive state after exceeding its critical current. This localized loss of superconductivity generates a voltage rise, serving as an essential signal for quench detection and protection. While capable of carrying extremely high currents, REBCO is mechanically brittle and have slow quench propagation which makes voltage change difficult to detect.

Ju, Han [Northwestern U.]↗
DOE OSTI2025

SAGAbg. III. Environmental Stellar Mass Functions, Self-quenching, and the Stellar-to-halo Mass Relation in the Dwarf Galaxy Regime

Recent efforts have extended our view of the number and properties of satellite galaxies beyond the Local Group firmly down to M ⋆ ∼ 10 6 M ⊙ . A similarly complete view of the field dwarf population has lagged behind. Using the background galaxy sample from the Satellites Around Galactic Analogs (SAGA) survey at z < 0.05, we take inventory of the dwarf population down to M ⋆ ∼ 5 × 10 6 M ⊙ using three metrics: the stellar mass function (SMF) as a function of environment, the stellar-to-halo mass relation (SHMR) of dwarf galaxies inferred via abundance matching, and the quenched fraction of highly isolated dwarfs. We find that the low-mass SMF shape shows minimal environmental dependence, with the field dwarf SMF described by a low-mass power-law index of α 1 = −1.44 ± 0.09 down to M ⋆ ∼ 5 × 10 6 M ⊙ , and that the quenched fraction of isolated dwarfs drops monotonically to f q ∼ 10 −3 at M ⋆ ∼ 10 8.5 M ⊙ . Though slightly steeper than estimates from H I kinematic measures, our inferred SHMR agrees with literature measurements of satellite systems, consistent with minimal environmental dependence of the SHMR in the probed mass range. Finally, although most contemporary cosmological simulations against which we compare accurately predict the SAGAbg-SMF SHMR, we find that big-box cosmological simulations largely overpredict isolated galaxy quenched fractions via a turnaround in f q (M ⋆ ) at 10 8 ≲ M ⋆ /M ⊙ ≲ 10 9 , underscoring the complexities in disentangling the drivers of galaxy formation and the need for systematic multidimensional observations of the dwarf population across environments.

Kado-Fong, Erin [Yale Univ., New Haven, CT (United↗
NASA NTRS1972

Measurements of O(1 D) quenching rates in the F-region

In-situ determinations of the quenching of O(1 D) atoms by N2 and O2 molecules were made from observations of 6300 A nightglow intensity enhancements produced by the Platteville 1.6 MW transmitter. The heating of F-region electrons near the point of reflection of the RF wave leads to electron impact excitation of oxygen atoms to the O(1 D) state. It is shown that the resulting region of enhance 6300 A emission is localized to the region of electron energy absorption for heating at the lower altitudes. At 225 km the measured time constants for intensity buildup following transmitter turn-on and for intensity decay following turn-off are identical and equal to (13 plus or minus 1) sec. Time constants varying from 30 to 80 sec are found for the altitude range 260 to 300 km. The inferred quenching coefficient for the whole altitude range, 225 to 300 km, is 4.4 + 2 or - 1 x 10 to the minus 11th power cu cm/sec at 950 K, in good agreement with laboratory data. The quenching frequency obtained at 225 km, when referred to the altitude 120 km, is equal to (21 plus or minus 2)/sec, in agreement with less direct ionospheric determinations.

Sipler, D. P.↗
NASA NTRS1974

Strengthening silicon carbide by quenching

Quenching was used to form compressive surface layers in hot-pressed silicon carbide. The presence of the compressive stresses was verified by slotted rod tests. The slotted rod tip deflection was retained at temperatures to at least 1380 C, showing that the stresses are not relieved immediately at elevated temperatures. The flexural strength and impact resistance of specimens quenched from moderate temperatures (2000 C) were increased. Frequently, specimens quenched from higher temperatures were weakened by thermal shock damage.

Gruver, R. M.↗
NASA NTRS1976

A stop-restart solid propellant study with salt quench

Experiments were conducted to gain insight into the unsatisfactory performance of the salt quench system of solid propellants in earlier studies. Nine open-air salt spray tests were conducted and high-speed cinematographic coverage was obtained of the events. It is shown that the salt spray by the detonator is generally a two-step process yielding two different fractions. The first fraction consists of finely powdered salt and moves practically unidirectionally at a high velocity (thousand of feet per second) while the second fraction consists of coarse particles and moves randomly at a low velocity (a few feet per second). Further investigation is required to verify the speculation that a lower quench charge ratio (weight of salt/propellant burning area) than previously employed may lead to an efficient quench

Kumar, R. N.↗
NASA NTRS1985

Quenching Effects on Iron Site Partitioning in the Apollo 17 Orange Glass Composition

Mare petrogenesis and the structure of the lunar interior were studied. Analyses of the spectral signatures of glasses was useful to remote sensing applications in areas of the moon where glass is in significant proportions in the lunar soil. The studies provided information on Fe site occupancies in glasses, which are used to construe oxygen fugacities at the lunar surface. Data were obtained through work on synthetic analogues of lunar glasses. However, recent Mossbauer studies of an Apollo 15 green glass composition have shown that synthetic glasses are extremely sensitive to variations in quenching media. Glass structure and Fe(3+)/Fe(2+) ratios are strongly controlled by quenching conditions, which may mask the effects of the original glass' formation temperature or oxygen partial pressure. Synthetic glasses were often run at low fugacities on Pt wires. The effects of quench media on the Apollo 17 orange glass composition are considered.

Dyar, M. D.↗
NASA NTRS1986

Temperature dependent electronic quenching of OH(A 2 Sigma +, v-prime = 0) between 230 and 310 K

The present study is concerned with the electronic quenching of OH(A 2 Sigma +, v-prime = 0) at and below room temperature, taking into account the use of laser-induced fluorescence (LIF) in a low pressure flow cell for H2, CO2, O2, and N2 colliders. The reasons for the selection of the temperature range and the collision partners are related to the quantitative calibration of OH detection techniques in the troposphere, and to considerations of electronic quenching dynamics. Attention is given to production and rotational distribution, temperature measurements, and temperature dependent quenching rate constants.

Copeland, R. A.↗
NASA NTRS1986

Electronic energy transfer and quenching in copolymers of styrene and 2-(2-prime-hydroxy -5-prime-vinylphenyl)-2H-benzotriazole Photochemical processes in polymeric systems. X

Intensity and lifetime quenching of the polystyrene monomer and excimer fluorescence emission by a pendant quencher have been studied in the solid state and in solution for a series of copolymers of styrene and 2-(2-prime-hydroxy-5-prime-vinylphenyl)-2H-benzotriazole. Two mechanisms of quenching have been identified. One involves interception of the migrating monomer excitation by the quencher, and the other involves a single-step Foerster energy-transfer process from the excimer traps to a quencher. The relative efficiencies of these two quenching mechanisms in the solid state and in solution have been compared and related to the efficiency of electronic energy migration. An estimate of the excimer trap concentration in solid polystyrene is also reported.

Coulter, D. R.↗
NASA NTRS1986

The quenching rate of O(1D) by O(3P)

The rate coefficient for the quenching of O(1D) by O(3P) has recently been calculated by Yee et al. (1985). Their results indicate that quenching by atomic oxygen should not be ignored in the analysis of the 6300 A emission airglow. Data obtained by the Visible Airglow Experiment on board the AE satellites have been reanalyzed to determine the quenching rate of O(1D) by atomic oxygen. The results of this analysis are presented.

Abreu, V. J.↗
NASA NTRS1988

Collisional quenching of cometary emission in the 18 centimeter OH transitions

A model of collisional quenching of the OH 2Pi(3/2) J = 3/2 Lambda doublet in cometary comae is presented. It is found that collisions with ions and electrons in the outer coma have a strong quenching effect on the Swings-effect inversion of the Lambda doublet that is responsible for the OH radio emission at 18 cm wavelength. For the conditions of Halley's comet, collisional quenching should lead radio observers to systematically underestimate the OH parent production rate by a factor of approximately 3 relative to its actual value, and in general, radio-derived production rates should always be less than or equal to UV-derived production rates, which are relatively unaffected by this process. The observation that UV production rates exceed those derived by radio techniques is well known; the direct measurement of this ratio, using a consistent coma model, should provide information about the ion and electron content of the cometary coma.

Schloerb, F. Peter↗
NASA NTRS1990

Quenching of A 2Sigma(+) OH at 300 K by several colliders

Quenching cross sections, sigma(Q), were measured for A 2Sigma(+) OH for a variety of colliders, using the pressure dependence of time-resolved laser-induced fluorescence to obtain quenching cross sections. The OH radicals, produced in a discharge or by photolysis, were maintained in the excited state at 300 K by an Ar buffer bath. It was found that quenching by CF4 and C2F6 the cross sections are very small. For Kr and Ze, the sigma(Q) values were found to be 8 and 27 sq A, respectively. For O2, sigma(Q) was 18 sq A, and for H2O, sigma(Q) was 80 sq A.

Wysong, Ingrid J.↗