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DOE OSTI2018

Role of Multiple Charge States of Ce in the Scintillation of AB O 3 Perovskites

Ce-activated A 2+ B 4+ O 3 perovskites represent a class of compounds currently under active exploration for their potential as scintillators. Depending on the chemistry and synthesis conditions, perovskites can crystallize in multiple crystal structures, and a Ce substitutional dopant in an ABO 3 perovskite can adopt different charge states (i.e., Ce 3+ or Ce 4+ ) as well as different substitutional sites (namely, the 12-fold-coordinated A site or the octahedrally coordinated B site). We use first-principles density-functional-theory- and hybrid-functional-based computations to study relative trends in the structure, energetics, and electronic structure of bulk ABO 3 perovskites, where A = Ca, Sr, or Ba and B = Hf or Zr. Subsequently, we consider the relative energetics of preferential solution sites for Ce as a function of charge states, chemical potential, and defect configurations. Our results reveal that while Ce 3+ or Ce 4+ defects can be thermodynamically stable, depending on the choice of the substitutional site and synthesis conditions (i.e., prevailing chemical potential), only Ce 3+ dopant at the A site leads to an electronic structure that can exhibit scintillation. Our comparative analysis shows that while the positions of the 5 d 1 and 4$\mathcal{f}$ levels of Ce 3+ as a dopant at the A site are favorably placed in the band structure, these levels are consistently higher for the Ce 4+ charge state and are unlikely to manifest any luminescence. The findings of this study are also discussed in relation to previously reported results and display excellent agreement with past experimental observations. In general, it is demonstrated that control of the Ce charge state and local chemical environment can be used—in addition to band-gap and band-edge engineering—to manipulate the relative position of scintillating states with respect to the valence-band maximum and conduction-band minimum. While this study specifically focuses on perovskites, the results (in particular, the relative alignment of the positions of the 5 d 1 and 4$\mathcal{f}$ levels of Ce dopant as a function of the activator’s charge state) are expected to be general and thus transferable to other chemistries.

36 MATERIALS SCIENCE↗

DOE OSTI2014

Role of Ce 4 + in the scintillation mechanism of codoped Gd 3 Ga 3 Al 2 O 12 : Ce

To control the time-response performance of widely used cerium-activated scintillators in cutting-edge medical-imaging devices, such as time-of-flight positron-emission tomography, a comprehensive understanding of the role of Ce valence states, especially stable Ce 4+ , in the scintillation mechanism is essential. However, despite some progress made recently, an understanding of the physical processes involving Ce 4+ is still lacking. The aim of this work is to clarify the role of Ce 4+ in scintillators by studying Ca 2+ codoped Gd 3 Ga 3 Al 2 O1 2 ∶Ce (GGAG∶Ce). By using a combination of optical absorption spectra and x-ray absorption near-edge spectroscopies, the correlation between Ca 2+ codoping content and the Ce 4+ fraction is seen. The energy-level diagrams of Ce 3+ and Ce 4+ in the Gd 3 Ga 3 Al 2 O 12 host are established by using theoretical and experimental methods, which indicate a higher position of the 5d 1 state of Ce 4+ in the forbidden gap in comparison to that of Ce 3+ . Underlying reasons for the decay-time acceleration resulting from Ca 2+ codoping are revealed, and the physical processes of the Ce 4+ -emission model are proposed and further demonstrated by temperature-dependent radioluminescence spectra under x-ray excitation.

Wu, Yuntao↗

DOE OSTI2017

Direct detection of sub-GeV dark matter with scintillating targets

We suggest a novel experimental concept for detecting MeV-to-GeV-mass dark matter, in which the dark matter scatters off electrons in a scintillating target and produces a signal of one or a few photons. New large-area photodetectors are needed to measure the photon signal with negligible dark counts, which could be constructed from transition edge sensor (TES) or microwave kinetic inductance detector (MKID) technology. Alternatively, detecting two photons in coincidence may allow the use of conventional photodetectors like photomultiplier tubes. Here we describe why scintillators may have distinct advantages over other experiments searching for a low ionization signal from sub-GeV dark matter, as there are fewer potential sources of spurious backgrounds. We discuss various target choices, but focus on calculating the expected dark matter-electron scattering rates in three scintillating crystals: sodium iodide (NaI), cesium iodide (CsI), and gallium arsenide (GaAs). Among these, GaAs has the lowest band gap (1.52 eV) compared to NaI (5.9 eV) or CsI (6.4 eV), which in principle allows it to probe dark matter masses as low as ~0.5 MeV, compared to ~1.5 MeV with NaI or CsI. We compare these scattering rates with those expected in silicon (Si) and germanium (Ge). The proposed experimental concept presents an important complementary path to existing efforts, and its potential advantages may make it the most sensitive direct-detection probe of dark matter down to MeV masses.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2019

Defect chemistry of Eu dopants in NaI scintillators studied by atomically resolved force microscopy

Activator impurities and their distribution in the host lattice play a key role in scintillation phenomena. In this work a combination of cross-sectional noncontact atomic force microscopy, x-ray photoelectron spectroscopy, and density-functional theory were used to study the distribution of Eu 2+ dopants in a NaI scintillator activated by 3% EuI 2 . A variety of Eu-based structures were determined in crystals subjected to different postgrowth treatments. Transparent crystals with good scintillation properties contained mainly small precipitates with a cubic crystal structure and a size below 4 nm. Upon annealing, Eu segregated toward the surface, resulting in the formation of an ordered hexagonal overlayer with a EuI 2 composition and a pronounced, unidirectional moiré pattern. Crystals with poor optical transparency showed a significant degree of mosaicity and the presence of precipitates. All observed crystals contained a very low concentration of Eu dopants present as isolated point defects; most of the europium was incorporated in larger structures.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2019

Neutron Imaging With Li-Glass Based Multicore SCIntillating FIber (SCIFI)

The improvement of neutron imaging towards and beyond the microscale is a well-documented need for the iterative characterization and modeling of numerous microstructured X-ray opaque materials. This work presents the recent progress in evaluating a SCIntillating FIber (SCIFI) proof-of-concept towards micron-level thermal neutron radiography. These SCIFIs are composed of 6 Li-enriched silicate glass cores doped with a Ce activator. The cores possess ~8.5 μm diameters and ~10 μm pitch following fiber drawing with a cladding glass into an all-solid multicore fiber. A polished 5 mm × 5 mm array of 100 microstructured multicore SCIFI pixels was fabricated into a 1 mm thick faceplate. The neutron efficiency and light yield of the faceplate are characterized as functions of the 7.38 weight percent of Li 2 O, thickness, and the 70% active volume. It was determined that approximately 39% of a thermal neutron (2 Å) beam can be absorbed by the faceplate. The 6 L i ( n , α ) t reaction is estimated to produce 7,700 ± 1,000 scintillation photons per event, referencing light collection from 241 Am irradiation of the faceplate. Simulations suggest that on average 17.5 ± 1.4% of these photons will be transported to an end of the fiber array for a thermal beam, with at least 7.2% of that total scintillation light being confined into the fiber cores in which it originated. The SCIFI faceplate was integrated into the Neutron Microscope (NM) at the Pulse OverLap DIffractometer (POLDI) beamline located at the Paul Scherrer Institut to image a Siemens star test object. Processed neutron radiographs acquired with the proof-of-concept faceplate resolved features at a state-of-the-art resolution of 16.1 ± 0.5 μm. The potential for even high resolution designs having smaller pitch or different cladding material is discussed.

47 OTHER INSTRUMENTATION↗

DOE OSTI2014

Radiation response of inorganic scintillators: Insights from Monte Carlo simulations

The spatial and temporal scales of hot particle thermalization in inorganic scintillators are critical factors determining the extent of second- and third-order nonlinear quenching in regions with high densities of electron-hole pairs, which, in turn, leads to the light yield nonproportionality observed, to some degree, for all inorganic scintillators. Therefore, kinetic Monte Carlo simulations were performed to calculate the distances traveled by hot electrons and holes as well as the time required for the particles to reach thermal energy following γ-ray irradiation. CsI, a common scintillator from the alkali halide class of materials, was used as a model system. Two models of quasi-particle dispersion were evaluated, namely, the effective mass approximation model and a model that relied on the group velocities of electrons and holes determined from band structure calculations. Both models predicted rapid electron-hole pair recombination over short distances (a few nanometers) as well as a significant extent of charge separation between electrons and holes that did not recombine and reached thermal energy. However, the effective mass approximation model predicted much longer electron thermalization distances and times than the group velocity model. Comparison with limited experimental data suggested that the group velocity model provided more accurate predictions. Nonetheless, both models indicated that hole thermalization is faster than electron thermalization and thus is likely to be an important factor determining the extent of third-order nonlinear quenching in high-density regions. The merits of different models of quasi-particle dispersion are also discussed.

Prange, Micah P.↗

DOE OSTI2014

SU-E-T-289: Scintillating Fiber Based In-Vivo Dose Monitoring System to the Rectum in Proton Therapy of Prostate Cancer: A Geant4 Monte Carlo Simulation

Purpose: To construct a dose monitoring system based on an endorectal balloon coupled to thin scintillating fibers to study the dose delivered to the rectum during prostate cancer proton therapy Methods: The Geant4 Monte Carlo toolkit version 9.6p02 was used to simulate prostate cancer proton therapy treatments of an endorectal balloon (for immobilization of a 2.9 cm diameter prostate gland) and a set of 34 scintillating fibers symmetrically placed around the balloon and perpendicular to the proton beam direction (for dosimetry measurements) Results: A linear response of the fibers to the dose delivered was observed within <2%, a property that makes them good candidates for real time dosimetry. Results obtained show that the closest fiber recorded about 1/3 of the dose to the target with a 1/r{sup 2} decrease in the dose distribution as one goes toward the frontal and distal top fibers. Very low dose was recorded by the bottom fibers (about 45 times comparatively), which is a clear indication that the overall volume of the rectal wall that is exposed to a higher dose is relatively minimized. Further analysis indicated a simple scaling relationship between the dose to the prostate and the dose to the top fibers (a linear fit gave a slope of −0.07±0.07 MeV per treatment Gy) Conclusion: Thin (1 mm × 1 mm × 100 cm) long scintillating fibers were found to be ideal for real time in-vivo dose measurement to the rectum for prostate cancer proton therapy. The linear response of the fibers to the dose delivered makes them good candidates of dosimeters. With thorough calibration and the ability to define a good correlation between the dose to the target and the dose to the fibers, such dosimeters can be used for real time dose verification to the target.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2014

SU-E-T-290: Secondary Dose Monitoring Using Scintillating Fibers in Proton Therapy of Prostate Cancer: A Geant4 Monte Carlo Simulation

Purpose: To monitor the secondary dose distribution originating from a water phantom during proton therapy of prostate cancer using scintillating fibers. Methods: The Geant4 Monte Carlo toolkit version 9.6.p02 was used to simulate prostate cancer proton therapy based treatments. Two cases were studied. In the first case, 8 × 8 = 64 equally spaced fibers inside three 4 × 4 × 2.54 cmm{sup 3} DuPont™ Delrin blocks were used to monitor the emission of secondary particles in the transverse (left and right) and distal regions relative to the beam direction. In the second case, a scintillating block with a thickness of 2.54 cm and equal vertical and longitudinal dimensions as the water phantom was used. Geometrical cuts were used to extract the energy deposited in each fiber and the scintillating block. Results: The transverse dose distributions from secondary particles in both cases agree within <5% and with a very good symmetry. The energy deposited not only gradually increases as one moves from the peripheral row fibers towards the center of the block (aligned with the center of the prostate) but also decreases as one goes from the frontal to distal region of the block. The ratio of the doses from the prostate to the ones in the middle two rows of fibers showed a linear relationship with a slope (−3.55±2.26) × 10−5 MeV per treatment Gy. The distal detectors recorded a very small energy deposited due to water attenuation. Conclusion: With a good calibration and the ability to define a good correlation between the dose to the external fibers and the prostate, such fibers can be used for real time dose verification to the target.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-D-206-06: Task-Specific Optimization of Scintillator Thickness for CMOS-Detector Based Cone-Beam Breast CT

Purpose: To optimize the cesium iodide (CsI:Tl) scintillator thickness in a complimentary metal-oxide semiconductor (CMOS)-based detector for use in dedicated cone-beam breast CT. Methods: The imaging task considered was the detection of a microcalcification cluster comprising six 220µm diameter calcium carbonate spheres, arranged in the form of a regular pentagon with 2 mm spacing on its sides and a central calcification, similar to that in ACR-recommended mammography accreditation phantom, at a mean glandular dose of 4.5 mGy. Generalized parallel-cascades based linear systems analysis was used to determine Fourier-domain image quality metrics in reconstructed object space, from which the detectability index inclusive of anatomical noise was determined for a non-prewhitening numerical observer. For 300 projections over 2π, magnification-associated focal-spot blur, Monte Carlo derived x-ray scatter, K-fluorescent emission and reabsorption within CsI:Tl, CsI:Tl quantum efficiency and optical blur, fiberoptic plate transmission efficiency and blur, CMOS quantum efficiency, pixel aperture function and additive noise, and filtered back-projection to isotropic 105µm voxel pitch with bilinear interpolation were modeled. Imaging geometry of a clinical prototype breast CT system, a 60 kV Cu/Al filtered x-ray spectrum from 0.3 mm focal spot incident on a 14 cm diameter semi-ellipsoidal breast were used to determine the detectability index for 300–600 µm thick (75µm increments) CsI:Tl. The CsI:Tl thickness that maximized the detectability index was considered optimal. Results: The limiting resolution (10% modulation transfer function, MTF) progressively decreased with increasing CsI:Tl thickness. The zero-frequency detective quantum efficiency, DQE(0), in projection space increased with increasing CsI:Tl thickness. The maximum detectability index was achieved with 525µm thick CsI:Tl scintillator. Reduced MTF at mid-to-high frequencies for 600µm thick CsI:Tl lowered the detectability index than 525µm CsI:Tl. Conclusion: For the x-ray spectrum and imaging conditions considered, a 525µm thick CsI:Tl scintillator integrated with the CMOS detector is optimal for detecting microcalcification cluster. Funding support: Supported in part by NIH R01 CA195512. The contents are solely the responsibility of the authors and do not reflect the official views of the NIH or the NCI. Disclosures: SV, GV and AK - Research collaboration, Koning Corp., West Henrietta, NY.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-F-T-180: Evaluation of a Scintillating Screen Detector for Proton Beam QA and Acceptance Testing

Purpose: To test the performance of a commercial scintillating screen detector for acceptance testing and Quality Assurance of a proton pencil beam scanning system. Method: The detector (Lexitek DRD 400) has 40cm × 40cm field, uses a thin scintillator imaged onto a 16-bit scientific CCD with ∼0.5mm resolution. A grid target and LED illuminators are provided for spatial calibration and relative gain correction. The detector mounts to the nozzle with micron precision. Tools are provided for image processing and analysis of single or multiple Gaussian spots. Results: The bias and gain of the detector were studied to measure repeatability and accuracy. Gain measurements were taken with the LED illuminators to measure repeatability and variation of the lens-CCD pair as a function with f-stop. Overall system gain was measured with a passive scattering (broad) beam whose shape is calibrated with EDR film placed in front of the scintillator. To create a large uniform field, overlapping small fields were recorded with the detector translated laterally and stitched together to cover the full field. Due to the long exposures required to obtain multiple spills of the synchrotron and very high detector sensitivity, borated polyethylene shielding was added to reduce direct radiation events hitting the CCD. Measurements with a micro ion chamber were compared to the detector’s spot profile. Software was developed to process arrays of Gaussian spots and to correct for radiation events. Conclusion: The detector background has a fixed bias, a small component linear in time, and is easily corrected. The gain correction method was validated with 2% accuracy. The detector spot profile matches the micro ion chamber data over 4 orders of magnitude. The multiple spot analyses can be easily used with plan data for measuring pencil beam uniformity and for regular QA comparison.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-F-T-559: High-Resolution Scintillating Fiber Array for In-Vivo Real-Time SRS and SBRT Patient QA

Purpose: A high-resolution scintillating fiber detector was built for in-vivo real-time patient specific quality assurance (QA). The detector is designed for stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) to monitor treatment delivery and detect real-time deviations from planned dose to increase patient safety and treatment accuracy. Methods: The detector consists of two high-density scintillating fiber arrays layered to form an X-Y grid which can be attached to the accessory tray of a medical linac for SBRT and cone SRS treatment QA. Fiber arrays consist of 128 scintillating fibers embedded within a precision-machined, high-transmission polymer substrate with 0.8mm pitch. The fibers are coupled on both ends to high-sensitivity photodetectors and the output is recorded through a high-speed analog-to-digital converter to capture the linac pulse sequence as treatment delivery progresses. The detector has a software controlled 360 degree rotational system to capture angular beam projections for high-resolution beam profile reconstruction. Results: The detector was validated using SRS cone sizes from 6mm to 34mm and MLC defined field sizes from 5×5mm2 to 100×100mm2. The detector output response is linear with dose and is dose rate independent. Each field can be reconstructed accurately with a spatial resolution of 0.8mm and the current beam output is displayed every 50msec. Dosimetric errors of 1% with respect to the treatment plan can be identified and clinically significant deviations from the expected treatment can be displayed in real-time to alert the therapists. Conclusion: The high resolution detector is capable of reconstructing beam profiles in real-time with submillimeter resolution and 1% dose resolution. This system has the ability to project in-vivo both spatial and dosimetric errors during SBRT and SRS treatments when only a non-clinically significant fraction of the intended dose was delivered. The device has the potential to establish new standards for in-vivo patient specific QA.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

A scintillator-based approach to monitor secondary neutron production during proton therapy

Here, the primary objective of this work is to measure the secondary neutron field produced by an uncollimated proton pencil beam impinging on different tissue-equivalent phantom materials using organic scintillation detectors. Additionally, the Monte Carlo code mcnpx-PoliMi was used to simulate the detector response for comparison to the measured data. Comparison of the measured and simulated data will validate this approach for monitoring secondary neutron dose during proton therapy. Proton beams of 155- and 200-MeV were used to irradiate a variety of phantom materials and secondary particles were detected using organic liquid scintillators. These detectors are sensitive to fast neutrons and gamma rays: pulse shape discrimination was used to classify each detected pulse as either a neutron or a gamma ray. The mcnpx-PoliMi code was used to simulate the secondary neutron field produced during proton irradiation of the same tissue-equivalent phantom materials. As a result, an experiment was performed at the Loma Linda University Medical Center proton therapy research beam line and corresponding models were created using the mcnpx-PoliMi code. The authors’ analysis showed agreement between the simulations and the measurements. The simulated detector response can be used to validate the simulations of neutron and gamma doses on a particular beam line with or without a phantom. In conclusion, the authors have demonstrated a method of monitoring the neutron component of the secondary radiation field produced by therapeutic protons. The method relies on direct detection of secondary neutrons and gamma rays using organic scintillation detectors. These detectors are sensitive over the full range of biologically relevant neutron energies above 0.5 MeV and allow effective discrimination between neutron and photon dose. Because the detector system is portable, the described system could be used in the future to evaluate secondary neutron and gamma doses on various clinical beam lines for commissioning and prospective data collection in pediatric patients treated with proton therapy.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2014

Recording of relativistic particles in thin scintillators

Results of investigating an assembly of thin scintillators and silicon photomultipliers for registering relativistic particles with the minimum ionization are presented. A high efficiency of registering relativistic particles using an Ej-212 plastic scintillator, BSF-91A wavelength-shifting fiber (Saint-Gobain), and a silicon photomultiplier (Hamamtsu) is shown. The measurement results are used for creating a scintillation hodoscope of the magnetic spectrometer for registering γ quanta in the GlueX experiment.

Tolstukhin, I A.↗

DOE OSTI2025

Scintillating glass for precision calorimetry in nuclear physics

High-performance scintillator materials are needed for particle identification and measurements of energy and momentum of electromagnetic particles in modern nuclear physics experiments. As an example, the US Electron-Ion Collider, a unique collider with diverse physics topics, requires electromagnetic calorimetry enabling high-quality electron identification and detection in the momentum range of 0.3 to tens of GeV. The highest resolution in electromagnetic calorimeters can be provided by homogeneous materials, e.g., lead tungstate crystals. Inorganic glass scintillators have been investigated as an attractive and cost-effective alternative to crystals, that is also easier and faster to manufacture in mass production. In this paper, we discuss progress in the fabrication and characterization of recent scintillating glass samples on both test bench and beam tests. Further, the results are well-reproduced by simulation and are discussed in the context of the Electron-Ion Collider experimental requirements and bench-marked against lead tungstate crystals.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2018

Temperature Quenching in LAB based liquid scintillator

The effect of temperature changes on the light output of LAB based liquid scintillator is investigated in a range from –5 C to 30 °C with a-particles and electrons in a small scale setup. Two PMTs observe the scintillator liquid inside a cylindrically shaped aluminum cuvette that is heated or cooled and the temperature dependent PMT sensitivity is monitored and corrected. The a-emitting isotopes in dissolved radon gas and in natural Samarium (bound to a LAB solution) excite the liquid scintillator mixtures and changes in light output with temperature variation are observed by fitting light output spectra. Furthermore, also changes in light output by compton electrons, which are generated from external calibration g-ray sources, is analysed with varying temperature. Assuming a linear behaviour, a combined negative temperature coefficient of (–0:29 0:01) % /°C is found. Considering hints for a particle type dependency, electrons show (–0:17 0:02) % /°C, whereas the temperature dependency seems stronger for a-particles, with (–0:35 0:03) % /°C. Furthermore, due to a high sampling rate, a pulse shape analysis can be performed and shows an enhanced slow decay component at lower temperatures, pointing to reduced non-radiative triplet state de-excitations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2014

Intuitive model for the scintillations of a partially coherent beam

We developed an intuitive model for the scintillation index of a partially coherent beam in which essentially the only critical parameter is the properly defined Fresnel number equal to the ratio of the “working” aperture area to the area of the Fresnel zone. The model transpired from and is supported by numerical simulations using Rytov method for weak fluctuations regime and Tatarskii turbulence spectrum with inner scale. The ratio of the scintillation index of a partially coherent beam to that of a plane wave displays a characteristic minimum, the magnitude of which and its distance from the transmitter are easily explained using the intuitive model. Furthermore, a theoretical asymptotic is found for the scintillation index of a source with decreasing coherence at this minimum.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2014

Advanced plastic scintillators for fast neutron discrimination

The present work addresses the need for solid-state, fast neutron discriminating scintillators that possess higher light yields and faster decay kinetics than existing organic scintillators. These respective attributes are of critical importance for improving the gamma-rejection capabilities and increasing the neutron discrimination performance under high-rate conditions. Two key applications that will benefit from these improvements include large-volume passive detection scenarios as well as active interrogation search for special nuclear materials. Molecular design principles were employed throughout this work, resulting in synthetically tailored materials that possess the targeted scintillation properties.

36 MATERIALS SCIENCE↗

DOE OSTI2015

LiCaAIF 6 :Eu Scintillator Family Neutron Detection (Final Report)

The proposed work was based on a learning cycle format with three parts, (1) Modeling, (2) Growth, (3) Characterization, to investigate the family of colquiriite scintillators and various activating dopants as efficiently and effectively as possible. Under this research methodology, each of these functions would feed information to the next. Each iteration around the cycle was expected to improve results and provide clues to the best path forward for the next iteration. However, it was realized that this research model is not robust and unable to handle setbacks at any one of the functions. Unfortunately, the project suffered setbacks in the “Growth” function and progress in the other functions was severely restricted. Of course, numerous alternative paths were trialed within the growth function to enable progress, but these required addition time and resources which in the end only provided limited progress. After reviewing the project as a whole, it can be concluded that the research model used was indeed too fragile for this sort of research and a more robust plan should be utilized in the future. As a whole though, significant progress was made toward understanding the barriers toward realizing the benefits of this family of scintillators through modeling. Various paths forward were postulated, but limited growth and synthesis capabilities prevented experimental validation. Experimentally, it was found that the synthesis and growth of colquiriite scintillators requires special considerations for its thermodynamic and chemical properties. These were overcome in the end and a new, lower cost growth method realized, but too late to have a significant impact in validating modeling hypotheses.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗