Array Detector Research Articles

Characterizing electron-collecting CdTe for use in a 77 ns burst-rate imager.

The Keck-PAD (pixel array detector) was developed at Cornell as a burst-rate imager capable of recording images from successive electron bunches (153 ns period) from the Advanced Photon Source (APS). Both Si and hole-collecting Schottky CdTe have been successfully bonded to this ASIC (application-specific integrated circuit) and used with this frame rate. The facility upgrades at the APS will lower the bunch period to 77 ns, which will require modifications to the Keck-PAD electronics to image properly at this reduced period. In addition, operation at high X-ray energies will require a different sensor material having a shorter charge collection time. For the target energy of 40 keV for this project, simulations have shown that electron-collecting CdTe should allow >90% charge collection within 35 ns. This collection time will be sufficient to sample the signal from one frame and prepare for the next. 750 µm-thick electron-collecting Schottky CdTe has been obtained from Acrorad and bonded to two different charge-integrating ASICs developed at Cornell, the Keck-PAD and the CU-APS-PAD. Carrier mobility has been investigated using the detector response to single X-ray bunches at the Cornell High Energy Synchrotron Source and to a pulsed optical laser. The tests indicate that the collection time will meet the requirements for 77 ns imaging.

Porphyrin Production by Corynebacterium diphtheriae Strains from Clinical Isolates.

Porphyrins are intermediate metabolites involved in the biosynthesis of vital molecules, including heme, cobalamin, and chlorophyll. Bacterial porphyrins are known to be proinflammatory and are associated with biofilm formation. This study investigated porphyrin production by strains of Corynebacterium diphtheriae using emission spectroscopy, high-performance liquid chromatography with fluorescence detection, diode array detector, and mass spectrometry. Emission spectroscopy revealed characteristic porphyrin emission spectra in all strains, with coproporphyrin III predominating. Qualitative analysis by different chromatographic methods identified coproporphyrin III, uroporphyrin I, and protoporphyrin IX in all strains. Quantitative analysis revealed strain-dependent coproporphyrin III production. Further studies are required to investigate the relationship between porphyrin production and the virulence potential of Corynebacterium diphtheriae.

Highly sensitive diamond X-ray detector array for high-temperature applications

Diamond is a highly suitable material for X-ray detectors that can function effectively in harsh environments due to its unique properties, such as an ultrawide bandgap, high resistance to radiation, excellent carrier mobility, and remarkable chemical and thermal stability. However, the sensitivity of diamond X-ray detectors needs further improvement due to the relatively low X-ray absorption efficiency of diamond, and the exploration of single-crystal diamond array imaging remains unexplored. Herein, a 10×10 X-ray photodetector array was constructed from single-crystal diamond. To improve the sensitivity of the diamond X-ray detector, an asymmetric sandwich electrode structure was utilized. Additionally, trenches are created through laser cutting to prevent crosstalk between adjacent pixels. The diamond X-ray detector array shows exceptional performance, including a low detection limit of 4.9 nGy s-1, a sensitivity of 14.3 mC Gy-1 cm-2, and a light-dark current ratio of 18312, which are among the most favorable values ever reported for diamond X-ray detectors. Furthermore, these diamond X-ray detectors can operate at high temperatures up to 450 °C, making them suitable for development in harsh environments.

Comparison of Gamma Analysis using Two Different Commercially available 2D Array Detectors for Pre-treatment Verification of Volumetric Modulated Arc Therapy

Comparison of Gamma Analysis using Two Different Commercially available 2D Array Detectors for Pre-treatment Verification of Volumetric Modulated Arc Therapy

Toward a new classification Method: Fractal dimension applied to chromatographic wine data

A study of Argentine wines was carried out by direct injection of the samples without previous treatment in a high-performance liquid chromatography system coupled to a diode array detector (HPLC-DAD). The collected data, corresponding to six different varietals (Bonarda, Cabernet Sauvignon, Malbec, Merlot, Syrah, and Tempranillo), were processed with a new chemometric approach: determining the fractal dimension of principal components or fractal dimension analysis (FDA). A comparative study of the efficiency of the new proposed model to discriminate wine samples according to botanical origin was made with methods based on a linear multivariate resolution curve-alternating least squares model (MCR-ALS) previously reported. The results show that the fractal dimension analysis of the data improves the discrimination between all the varietals studied, allowing better discrimination in relation to other reported methodologies. Finally, a comparative analysis of the method’s sustainability was carried out using the Analytical Eco-Scale indicator. This analysis demonstrated that the method based on fractal analysis is a simple procedure that meets most of the Green Analytical Chemistry requirements.

Bio-inspired flat optics for directional 3D light detection and ranging

The eyes of arthropods, such as those found in bees and dragonflies, are sophisticated 3D vision tools that are composed of an array of directional microlenses. Despite the attempts in achieving artificial panoramic vision by mimicking arthropod eyes with curved microlens arrays, a wealth of issues related to optical aberrations and fabrication complexity have been reported. However, achieving such a wide-angle 3D imaging is becoming essential nowadays for autonomous robotic systems, yet most of the available solutions fail to simultaneously meet the requirements in terms of field of view, frame rate, or resistance to mechanical wear. Metasurfaces, or planar nanostructured optical surfaces, can overcome the limitation of curved optics, achieving panoramic vision and selective focusing of the light on a plane. On-chip vertical integration of directional metalenses on the top of a planar array of detectors enables a powerful bio-inspired LiDAR that is capable of 3D imaging over a wide field of view without using any mechanical parts. Implementation of metasurface arrays on imaging sensors is shown to have relevant industrial applications in 3D sensing that goes beyond the basic usage of metalenses for imaging.

Development of a toroidally resolved broadband ECE imaging system for measurement of turbulent fluctuations on the KSTAR.

The two electron cyclotron emission imaging (ECEI) systems installed at adjacent ports (G and H) on the KSTAR tokamak incorporate large-aperture mm-wave optics, broadband electronics, and high speed digitization (up to 1 MSa/s) for 2D and quasi-3D visualization of MHD-scale fluid dynamics. Recently, the ECEI systems have been proved to be capable of visualization of smaller scale fluctuations albeit with a limited spatiotemporal resolution and even capable of measurement of ion cyclotron harmonic waves by direct high-speed sampling of the ECE IF signals. A four-channel prototype subsystem with a higher sampling rate up to 16 GS/s has been integrated into the G-port ECEI system, enabling the measurement of plasma waves in the GHz range in the form of modulated ECE signals and characterization of high-frequency turbulence during the evolution of pedestal. To achieve higher toroidal resolution in the turbulence measurement, the H-port ECEI system is now being upgraded to have a toroidally dual detector array of 2(toroidal) × 12(vertical) × 8(radial) channel configuration and a high-speed subsystem of 2(toroidal) × 4 channel configuration. The new mm-wave optics has been designed via beam propagation simulation, and the measured performance of the fabricated lens indicates a toroidal resolution of 8-10cm depending on the focus position and zoom factor, allowing for the measurement of parallel wavenumber up to k‖ ∼ 0.8cm-1.

First measurements of energetic protons in Mega Amp Spherical Tokamak Upgrade (MAST-U).

First proton production rates from the d(d,p)t reaction in the Mega Amp Spherical Tokamak Upgrade (MAST-U) are measured. The data were taken during the MAST-U experimental campaign with an upgraded version of the proton detector (PD) previously used in MAST. The new detector array consists of three collimated silicon surface barrier detectors with a depletion depth of 300μm and a collimated 120μm thick diamond detector, mounted on the MAST-U reciprocating probe arm. This array measures the energies of unconfined energetic 3MeV protons and 1MeV tritons mainly produced by beam-thermal DD reactions during neutral beam injection heating. Diamond detectors have the potential to be uniquely suited to detect charged fusion products as they promise to be much more radiation resistant and much less sensitive to temperature variations compared to silicon-based detectors. Using silicon and diamond-based detectors simultaneously allowed us to directly compare the performance of these two detector types. PD particle rates measured during different plasma scenarios are presented and compared to neutron rates measured using the neutron camera upgrade and TRANSP predictions.

Discovery of Very High Energy Gamma-Ray Emissions from the Low-luminosity AGN NGC 4278 by LHAASO

Abstract The first source catalog of the Large High Altitude Air Shower Observatory (LHAASO) reported the detection of a very high energy gamma-ray source, 1LHAASO J1219+2915. This Letter presents a further detailed study of the spectral and temporal behavior of this pointlike source. The best-fit position of the TeV source (R.A. = 185.°05 ± 0.°04, decl. = 29.°25 ± 0.°03) is compatible with NGC 4278 within ∼0.°03. Variation analysis shows an indication of variability on a timescale of a few months in the TeV band, which is consistent with low-frequency observations. Based on these observations, we report the detection of TeV γ-ray emissions from this low-luminosity active galactic nucleus. The observation by LHAASO's Water Cherenkov Detector Array during the active period has a significance level of 8.8σ with a best-fit photon spectral index Γ = 2.56 ± 0.14 and a flux f 1–10 TeV = (7.0 ± 1.1sta ± 0.35syst) × 10−13 photons cm−2 s−1, or approximately 5% of the Crab Nebula. The discovery of VHE gamma-ray emission from NGC 4278 indicates that compact, weak radio jets can efficiently accelerate particles and emit TeV photons.

Study of readout system for 3He linear position sensitive detectors

This study introduces a readout system for 3He linear position-sensitive detectors (LPSDs), tailored for the Small Angle Neutron Scattering (SANS) spectrometer of the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. Central to this system is the employment of a trapezoidal filter as the primary signal shaper, selected for its enhanced noise filtering capabilities and efficacy in mitigating ballistic deficit. Additionally, the integration of a digital CR filter aims to counteract baseline drift within trigger signals. This innovative architecture underwent validation via computer programs using experimental data, demonstrating superior performance in spatial resolution compared to conventional Gaussian filter-based approaches. Meanwhile, the improvement in spatial resolution comes with a narrower pulse width, promising a higher throughput at high count rates. When applied to a 16-tube detector module, the system achieved an average position resolution of 3.63 mm (FWHM) at the central region and 4.03 mm at the end regions. Furthermore, with a pusle width of 0.6 μs, the 96-tube detector array is promised to sustain a count rate over 1 Mcps.

Application of a kosmotrope (Na2CO3) and chaotrope (NaCl) in chemometric optimization of aqueous two-phase extraction of bioactive compounds in Hypoxis iridifolia.

Enterolactone, coumaric acid and vitexin are polyphenolic compounds present in a variety of fruits, vegetables, cereals and plants. These bioactive compounds are in high demand due to their antioxidant property in various tissues and organs. The purpose of this study was to develop a simultaneous extraction method, an aqueous two-phase extraction (ATPE) method, that would enable the extraction of these compounds from Hypoxis iridifolia. This environmentally friendly extraction method only applied water and ethanol as extraction solvents for these analytes from the plant matrix. After phase separation, the analytes were salted-out from the aqueous phase into the organic phase with the aid of a chaotrope (NaCl) or kosmotrope (Na2CO3). Thereafter, the analytes were withdrawn by a micro-pipette for analysis on the high-performance liquid chromatography-photodiode array detector. Optimization was conducted using a central composite design, where three parameters were examined which involved percentage ethanol, centrifugation time and salt type. Generally, the optimized conditions for extraction were an ethanol percentage of 100% and a centrifugation time of 10min, which yielded concentrations of 2942, 23,823 and 8881mg kg-1 for enterolactone, vitexin and coumaric acid, respectively, in the presence of a kosmotrope. The optimized conditions of extraction in the presence of chaotrope were an ethanol percentage of 66% and a centrifugation time of 10min with concentrations of 6727, 20,833 and 8618mg kg-1 for enterolactone, vitexin and coumaric acid, respectively. The ATPE method involving Na2CO3 was a better extractant of all the compounds studied relative to that of NaCl. The superior extraction capability of Na2CO3 in ATPE could serve as a prototype for the development of efficient extraction methods to meet the high demand for medicinal compounds derived from natural products.

Ultrasound-assisted matrix solid-phase extraction based on deep eutectic solvents and zinc oxide: Extraction and determination of six active ingredients in Ligustri Lucidi Fructus.

In this study, we propose a novel strategy utilizing deep eutectic solvents (DESs) as both the extraction solvent and dispersing liquid, with nanometer zinc oxide (ZnO) serving as the adsorbent. This method incorporates ultrasound-assisted matrix solid phase dispersion (UA-MSPD) for the extraction of six active components (salidroside, echinacoside, acteoside, specnuezhenide, nuezhenoside G13, and oleanolic acid) from Ligustri Lucidi Fructus samples. The extracts were then analyzed using high-performance liquid chromatography equipped with a diode array detector. The effects of various parameters such as dispersant dosage, DESs volume, grinding time, ultrasonication duration, and eluent volume on extraction recovery were investigated and optimized using a central composite design under response surface methodology. The optimized conditions yielded detection limits ranging from 0.003 to 0.01mg/g and relative standard deviations of 8.7% or lower. Extraction recoveries varied between 93% and 98%. The method demonstrated excellent linearity for the analytes (R2 ≥ 0.9997). The simple, green, and efficient DESs/ZnO-UA-MSPD technique proved to be rapid, accurate, and reliable for extracting and analyzing the six active ingredients in Ligustri Lucidi Fructus samples.

HPLC-DAD method for simultaneous determination of gallic acid, catechins, and methylxanthines and its application in quantitative analysis and origin identification of green tea

The high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) was optimized for the simultaneous determination of 11 compounds, belonging to polyphenols (gallic acid and seven catechins) and methylxanthines (caffeine, theobromine, and theophylline). The results obtained for all the validation parameters of the HPLC-DAD method showed that the method is sensitive enough for routine analysis with basic chromatographic equipment, thus it has a significant potential to be highly applicable in common laboratory practice. The method was used in the analysis of 60 green tea infusions originating from four tea-producing countries. The dataset contributes to enhancing current data on green tea. The analysis of green tea extracts revealed significant differences depending on the origin of the samples. Linear Discriminant Analysis (LDA) was applied to test the accuracy of identification of the origin of the tea samples, based on the chemical composition of tea with a focus on polyphenolic compounds and methylxanthines analysed in this study. Based on cross-validation results, the model showed 93.75 % accuracy in the classification of green tea originating from Japan, China (Mainland), China (Taiwan) and South Korea.

Design and thermal simulation of the front-end module for STARLIGHT

This paper presents a front-end module emulator for SemiconducTor Array detectoR with Large dynamIc ranGe and cHarge inTegrating readout (STARLIGHT), a versatile hybrid silicon pixel detector with a high frame rate (≥10kHz) and serving as the first charge-integrating pixel detector for XFEL in China. The detector is intended for operation in a vacuum environment, with the front-end module generating a thermal power of up to 5.443 mW/mm2, presenting a significant challenge for thermal management. To assess the thermal management capabilities of the mechanical and PCB designs for the project, a thermal emulator was developed to replicate the heat generated by the ASIC. This was particularly crucial during the early stages of the project when the ASIC was not yet available, achieved by placing copper wires on the PCB. Subsequent thermal simulations were conducted and compared with the results obtained from the thermal emulator. The comparison shows that the experimental results are very close to the thermal simulation results, validating the thermal performance of the STARLIGHT front-end modules. These endeavors not only provide validation but also offer valuable insights to ensure the thermal efficiency of the STARLIGHT front-end modules.

Perspective of perovskite-based X-ray hybrid pixel array detectors

Compound semiconductors are playing a major role in the production of X-ray pixel detectors for the application in laboratories and beamlines at photon sources. The performance of these detectors has constantly been improved for the last decades but experiments are still limited by the properties of the detector material, especially under high flux illumination. The fast development of perovskite crystals opens the possibility for new materials to be used as highly efficient X-ray pixel detectors. The published data until now, of the transport properties, demonstrate the large potential of perovskite semiconductors. The achieved values are comparable with the ones of CdTe-based detectors. This paper presents potential perovskite-based detector materials and compares their performance with the state-of-the-art CdTe-based detectors. The perspectives of perovskite semiconductors are promising for the production of large area X-ray detectors but still some challenges remain.

Toward real-time, volumetric dosimetry for FLASH-capable clinical synchrocyclotrons using protoacoustic imaging.

Fast low angle shot hyperfractionation (FLASH) radiotherapy (RT) holds promise for improving treatment outcomes and reducing side effects but poses challenges in radiation delivery accuracy due to its ultra-high dose rates. This necessitates the development of novel imaging and verification technologies tailored to these conditions. Our study explores the effectiveness of proton-induced acoustic imaging (PAI) in tracking the Bragg peak in three dimensions and in real time during FLASH proton irradiations, offering a method for volumetric beam imaging at both conventional and FLASH dose rates. We developed a three-dimensional (3D) PAI technique using a 256-element ultrasound detector array for FLASH dose rate proton beams. In the study, we tested protoacoustic signal with a beamline of a FLASH-capable synchrocyclotron, setting the distal 90% of the Bragg peak around 35mm away from the ultrasound array. This configuration allowed us to assess various total proton radiation doses, maintaining a consistent beam output of 21 pC/pulse. We also explored a spectrum of dose rates, from 15 Gy/s up to a FLASH rate of 48 Gy/s, by administering a set number of pulses. Furthermore, we implemented a three-dot scanning beam approach to observe the distinct movements of individual Bragg peaks using PAI. All these procedures utilized a proton beam energy of 180 MeV to achieve the maximum possible dose rate. Our findings indicate a strong linear relationship between protoacoustic signal amplitudes and delivered doses (R2=0.9997), with a consistent fit across different dose rates. The technique successfully provided 3D renderings of Bragg peaks at FLASH rates, validated through absolute Gamma index values. The protoacoustic system demonstrates effectiveness in 3D visualization and tracking of the Bragg peak during FLASH proton therapy, representing a notable advancement in proton therapy quality assurance. This method promises enhancements in protoacoustic image guidance and real-time dosimetry, paving the way for more accurate and effective treatments in ultra-high dose rate therapy environments.

On-site sensing for aflatoxicosis poisoning via ultraviolet excitable aptasensor based on fluorinated ethylene propylene strip: a promising forensic tool

The environmental contamination by extremophile Aspergillus species, i.e., Aflatoxin B1, is hardly controllable in Southeast Asia and Sub-Saharan Africa, which lack handling resources and controlled storage facilities. Acute aflatoxicosis poisoning from aflatoxin-prone dietary staples could cause acute hepatic necrosis, acute liver failure, and death. Here, as the cheaper, more straightforward, and facile on-site diagnostic kit is needed, we report an ultraviolet-excitable optical aptasensor based on a fluorinated ethylene propylene film strip. Molecular dynamics on the aptamer.AFB1 complex revealed that the AFB1 to the aptamer increases the overall structural stability, suggesting that the aptamer design is suitable for the intended application. Under various influencing factors, the proposed label-free strategy offers a fast 20-min on-site fabrication simplicity and 19-day shelf-life. The one-pot incubation provides an alternative to catalytic detection and exhibited 4 times reusability. The recovery of crude brown sugar, processed peanuts, and long-grain rice were 102.74 ± 0.41 (n = 3), 86.90 ± 3.38 (n = 3), and 98.50 ± 0.42 (n = 3), comparable to High-Performance Liquid Chromatography-Photodiode Array Detector results. This study is novel owing to the peculiar UV-active spectrum fingerprint and the convenient use of hydrophobic film strips that could promote breakthrough innovations and new frontiers for on-site/forensic detection of environmental pollutants.

Exploring Conventional and Green Extraction Methods for Enhancing the Polyphenol Yield and Antioxidant Activity of Hyssopus officinalis Extracts.

Hyssopus officinalis L. (HO) is, as one of the most prevalently utilized plants, used in traditional medicine to cure various diseases as well as the in food and cosmetic industries. Moreover, HO is a rich source of polyphenols with potent antioxidant properties. However, the studies on the extraction of such compounds from HO are scanty and sparse. This study aims to optimize the extraction of polyphenols and maximize the antioxidant activity in HO extracts. A comprehensive experimental design was employed, encompassing varied extraction parameters to determine the most effective ones. Alongside conventional stirring (ST), two green approaches, the ultrasonic treatment (US) and the pulsed electric field (PEF), were explored, either alone or in combination. The extracted polyphenolic compounds were identified with a high-performance liquid chromatography-diode array detector (HPLC-DAD). According to the results, the employment of ST along with an ethanolic solvent at 80 °C for 150 min seems beneficial in maximizing the extraction of polyphenols from HO, resulting in extracts with enhanced antioxidant activity. The total polyphenol was noted at 70.65 ± 2.76 mg gallic acid equivalents (GAE)/g dry weight (dw) using the aforementioned techniques, and the antioxidant activity was noted as 582.23 ± 16.88 μmol ascorbic acid equivalents (AAE)/g dw (with FRAP method) and 343.75 ± 15.61 μmol AAE/g dw (with the DPPH method). The as-prepared extracts can be utilized in the food and cosmetics industries to bestow or enhance the antioxidant properties of commercial products.

Effects of different postharvest drying processes on flavonoid content and enzymatic activity of Styphnolobium japonicum (L.) Schott flowers for industrial and medicinal use

Traditionally, fresh S. japonicum flowers (SJF) and S. japonicum flowers buds (SJFB) are dried prior to further processing and use. Here, we investigated the ways in which drying techniques, including sun drying (SD), steam drying (STD), microwave drying (MD), hot air drying (HAD, 40 °C, 60 °C, 80 °C, 100 °C), and freeze drying (FD), alter the flavonoid composition of freshly-harvested SJF and SJFB. The flavonoid content of dried samples was determined by Ultra High Performance Liquid Chromatography-Diode Array Detector (UPLC-DAD). Overall, different drying techniques had significantly different effects on the RU content, ranging from 10.63 % (HAD-80 °C) to 34.13 % (HAD-100 °C) in SJF and from 18.91 % (HAD-100 °C) to 29.16 % (HAD-40 °C) and 30.53 % (SD) in SJFB. To clarify the mechanism by which drying affects the RU content of S. japonicum flowers, we studied the activity of a rutin-hydrolyzing enzyme (RHE) isolated from SJF and SJFB using multiple separation and assay methods. According to the Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) results, the apparent molecular weight of the purified RHE was approximately 38 kDa. According to UPLC-DAD, RHE catalyzes the production of quercetin (QU) from rutin (RU), but not from other flavonoid glycosides. Drying fresh SJF and SJFB at low and high temperatures can inhibit RHE activity and prevent RU hydrolysis. Therefore, subjecting freshly-harvest SJF to HAD-100 °C, and freshly-harvest SJFB to SD or HAD-40 °C, can greatly increase the RU content. In particular, HAD is viable for large-scale application due to its simplicity and industrial feasibility.

Validation and measurement uncertainty of analytical methods for various azo dye adulterants in Curcuma longa L.

Food adulteration involving the illegal addition of dyes to foodstuffs has become an alarming issue in recent years. This study developed and validated a high-performance liquid chromatography (HPLC)-DAD (diode array detector) method for the simultaneous determination of nine azo dyes (Butter Yellow, Sudan Orange G, Para Red, Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red 7B, and Scarlet 808). Moreover, a qualitative analysis method using liquid chromatography-tandem mass spectrometry was developed to more accurately identify peaks detected in HPLC-DAD. The calibration curve represented good linearity (r2≥0.9998) over the measured concentration range of 0.5-25mg/kg. limit of detection and limit of quantification were 0.01-0.04 and 0.04-0.12mg/kg, respectively. Accuracy and precision were 96.0-102.6 and 0.16-2.01 (relative standard deviation%), respectively. Additionally, the measurement uncertainty and HorRat value were estimated. Several Curcuma longa L. distributed in Korea were collected and monitored for azo dye contaminants. PRACTICAL APPLICATION: The proposed HPLC-DAD method represents a significant advancement in the field, offering a reliable means of quantifying azo dyes and identifying their presence even at trace levels in adulterated turmeric. This not only contributes to ensuring the safety and integrity of turmeric products but also establishes precedent for robust analytical techniques in addressing food safety challenges.