Crystal Detector Research Articles

Growth and Characterization of AgBiS2 Bulk Single Crystals for Near-Infrared Detectors

Growth and Characterization of AgBiS₂ Bulk Single Crystals for Near-Infrared Detectors

Evaluation of biventricular function by cadmium-zinc-telluride SPECT gated tomographic radionuclide angiography: Comparison to conventional SPECT.

We compared and analyzed the consistency and repeatability of left and right ventricular ((LV/RV) functions obtained by gated-equilibrium radionuclide ventriculography (ERNV) with cadmium-zinc-telluride single-photon emission computed tomography (CZT-SPECT) and conventional SPECT (C-SPECT) with sodium iodide crystal detectors. Seventy-seven patients were included in the retrospective study. Both C-SPECT and CZT-SPECT imaging were performed on the same day. Correlations and differences in LV/RV ejection fraction (LVEF and RVEF), peak ejection rate (PER), and peak filling rate (PFR) were compared between the 2 models. Cardiac magnetic resonance (CMR) was partially used as the gold standard, and ultrasound results were included for comparative analysis. Interobserver reproducibility of each parameter obtained by the 2 cameras was compared. Between the 2 cameras, there were no significant difference in LVEF, LVPER, LVPFR, and RVPER (P > .05) and there were in RVEF and RVPFR (P < .05 or .001). The correlations (R value) were 0.831 (LVEF, excellent), 0.619 (RVEF, good), 0.672 (LVPER, good), 0.700 (LVPFR, good), 0.463 (RVPER, normal), and 0.253 (RVPFR, poor). There were no significant difference between CMR and CZT-SPECT in LVEF (P > .05) while there were between CMR and both C-SPECT and ultrasound (P < .05). The correlations were all good (R = 0.660, 0.658, and 0.695). There were no significant difference between CMR and both C-SPECT and CZT-SPET in RVEF (P > .05) and the correlations were good (R = 0.771 and 0.745). For repeatability, the intraclass correlation coefficient of RVPFR by C-SPECT was good (intraclass correlation coefficient = 0.698) and excellent for the rest of the groups (0.823-0.989). The repeatability of LVEF and RVEF was better for CZT-SPECT than for C-SPECT. The repeatability of PER was better for both cameras than PFR. CZT-SPECT tomographic ERNV correlated well with C-SPECT planar ERNV in evaluation of biventricular systolic function and LV diastolic function. Compared with the "gold standard" CMR, both models had good correlation in measuring LV/RVEF. CZT-SPECT had better inter-group reproducibility than C-SPECT. The accuracy of RV diastolic function need further study. CZT-SPECT tomographic ERNV will play an important and unique role in the clinical application of accurate evaluation of biventricular function in the future.

Conservation of Food, Medicinal and Dyes Crops Based on Local Community Wisdom in Mareje Village, West Lombok

Mareje Village, located in Sheet District, West Lombok Regency, NTB, Indonesia, is one of five villages and sub-districts in the Sheet District area. Nature protection is carried out to care for and protect natural resources, including flora, fauna, ecosystems and the environment. It involves a series of actions to ensure the sustainability and balance of ecosystems and natural habitats. This research aims to identify various food, medicinal and dye plants that have long been part of the conservation practices of the Mareje Village community. The research method used is descriptive qualitative, with data collected through trusted online sources, as well as interviews and questionnaires with local residents. The research results show that the people of Mareje Village still rely on various plants as a source of food, dyes and medicine. This includes rice, corn, cassava, taro, long beans, peanuts, green beans, and sweet potatoes for food; turmeric, pandan, katuk leaves, butterfly pea flowers, and dragon fruit for coloring; as well as white binahong, cat's whiskers, castor leaves, Chinese betel leaves, katuk leaves, black turmeric, bridal flowers, and horsewhip for medicine.

Absorption Spectra of AlGaN/GaN Terahertz Plasmonic Crystals-Experimental Validation of Analytical Approach.

Absorption spectra of AlGaN/GaN grating-gate plasmonic crystals with a period from 1 µm to 2.5 µm were studied experimentally at T = 70 K using Fourier-transform infrared spectrometry. The plasmonic crystals exhibit distinct absorption lines of various plasmon harmonics across the 0.5 to 6 THz frequency range, tunable by gate voltage. Cumbersome and time-consuming electromagnetic simulations are usually needed to interpret or predict the grating-gate crystal spectra. In this work, we examine an analytical model and show that it can successfully describe the majority of existing experimental results. In this way, we demonstrate a new analytical platform for designing plasmonic crystals for THz filters, detectors, and amplifiers.

Self-healing spiral phase contrast imaging

Spiral phase contrast imaging alleviates the information load by extracting the geometric features of objects and is one of the most representative branches of instant imaging processing. The self-healing capacity of edge detectors can enhance their robustness to obstacles in practical applications. Here, a self-healing spiral phase contrast imaging scheme is proposed and experimentally demonstrated by a liquid crystal edge detector combining a spiral phase, an axicon phase, and a lens phase. The spiral phase is encoded into a liquid crystal by photopatterning. Self-healing contrast imaging is characterized by a series of edge images of both high-contrast amplitude-type and low-contrast phase-type objects. This work extends the self-healing capacity of these detectors to instant imaging processing and paves the way for optical applications with self-healing features.

Freezing non-radiative recombination in high-performance CsPbBr3 single crystal x-ray detector

Though CsPbBr3 single crystals (SCs) possess intriguing photoelectronic properties for x/γ-ray detection, the serious ion migration and high thermally activated carrier concentration at room temperature (RT), typically associated with defect states in CsPbBr3 crystals, result in a high dark current and drift of baseline, hindering their potential applications. In this investigation, liquid nitrogen cooling is proposed to freeze deep-level defects in CsPbBr3 SCs, thereby suppressing the ion migrations and decreasing the thermally excited carrier concentration. Utilizing photoluminescence (PL) and time-resolved PL spectra, coupled with theoretical models for photoexcitation and photoemission processes, the freezing of deep-level defects at liquid nitrogen temperature (LNT) is confirmed, which is conducive to decreasing non-radiative recombination. At LNT, the CsPbBr3 SC exhibits a higher resistivity of 4.95 × 1011 Ω cm and a higher mobility–lifetime product of 9.54 × 10−3 cm2 V−1, in contrast to the RT values of 3.86 × 109 Ω cm and 3.67 × 10−3 cm2 V−1, respectively. Furthermore, the x-ray detector at LNT exhibits a high sensitivity of 9309 μC Gyair−1 cm−2 and an impressively low detection limit of 0.054 nGy s−1, which offers a route for obtaining highly sensitive x-ray detectors for applications including ultra-low dose radiation imaging.

PNIPAM microgel coatings of LiF crystal radiation detectors

Thin films of poly(N-isopropylacrylamide) (PNIPAM) microgels have recently attracted significant attention as promising candidates for creating switchable interfaces in biomedical and biotechnological applications. In this study, microgel films are proposed as smart coatings for photoluminescent solid-state radiation detectors based on lithium fluoride (LiF). Understanding the impact of the solid substrate is crucial for customising and refining microgel coatings for specific applications. To investigate the effects of surface quality, microgel size, and particle concentration on the properties of microgel films, PNIPAM microgels were spin-coated onto LiF crystal surfaces and characterised through wettability measurements, UV-Vis-NIR spectrophotometry, and Atomic Force Microscopy. This approach enabled effective control over the optical and morphological properties of the films, paving the way for the development of hybrid and potentially biocompatible radiation detectors using PNIPAM microgel films.

Investigation of X-rays Beams Uniformity in Radiotherapeutic Tumor Treatment Procedure Using LuAG:Ce Crystal Detectors.

In this study, Ce3+-doped Lu3Al5O12 garnet (LuAG) crystal detectors, with a density of ρ = 6 g/cm3 and an effective atomic number Zeff = 62, are proposed as promising materials for radiotherapy applications. This type of detector demonstrates excellent uniformity of structural and optical properties, high thermoluminescence (TL) light yield, optimal position of main TL glow peaks at temperatures around 245-295 °C, and high radiation stability. The set of TL detectors made from LuAG:Ce single crystal was used to evaluate the uniformity of dose and energy spectra of X-ray radiation from a clinical accelerator with 6 MV and 15 MV beams at the Department of Medical Physics, Oncology Center in Bydgoszcz, Poland, and γ-rays from a 60Co source at the National Institute of Oncology in Warsaw. The LuAG:Ce crystal detectors demonstrated highly promising results for registering X-ray radiation from accelerators with both 6 MV and 15 MV electron beams, as well as γ-rays from a 60Co source with energies of 1.17 and 1.33 MeV.

The Large Imaging Spectrometer for Solar Accelerated Nuclei (LISSAN): A next-generation solar gamma-ray spectroscopic imaging instrument concept

We present the Large Imaging Spectrometer for Solar Accelerated Nuclei (LISSAN), a new solar dedicated satellite instrument concept. LISSAN relies on an indirect Fourier imaging technique valid over an energy range from 40 keV up to 100 MeV. Spatial information is encoded into 15 moiré patterns by 15 pairs of slightly offset grids (bigrids) separated by a fixed distance enabling a predicted spatial resolution of 10”. The time, location, and energy of each incoming photon is recorded via a pixelated gadolinium aluminium gallium garnet (GAGG) crystal scintillator detector placed in alignment with each bigrid, therefore providing simultaneous imaging and spectroscopy from the same imaging system. X-ray and gamma-ray emission are key diagnostics of electron and ion acceleration, respectively. However, despite being a fundamental process that occurs throughout the Universe, particularly in the solar atmosphere, only one resolved gamma-ray image of ion acceleration in a solar flare has ever been achieved. LISSAN will shed new light on this process by providing spectral resolution better than 1.5% FWHM at 6.1 MeV, an imaging effective area at 2.2 MeV of 100 cm2 (more than 25 times greater than past missions such as RHESSI) and a 10 s cadence. Thanks to these significant advances over the previous satellite-based solar detectors, LISSAN will provide reliable imaging and the spectral characterization of both electron and ion acceleration in solar eruptive events simultaneously for the first time, enabling to it to answer several important open questions regarding solar particle acceleration and the initiation of space weather events.

X-ray spectrum estimation from the transmission method using the radioluminescence of an Al2O3:C crystal

The X-ray spectrum of X-ray tube is crucial for radiation dose calculations. Due to the high photon flux, it is difficult to directly measure the primary spectrum of X-ray tube. Transmission measurement is one of indirect method used to determine the primary spectrum of X-ray tube. Although the method is experimentally simple, X-ray spectrum estimation from transmission method is a seriously ill-conditioned problem. In this paper, a new transmission measurement instrument with an the Al2O3:C crystal detector is proposed. Real-time dose rate attenuation data from transmission method are collected by using the radioluminescence(RL) of the Al2O3:C crystal. The expectation-maximization (EM) method is applied for X-ray spectrum estimation from transmission method. The method is demonstrated on typical simulated spectra of 80,100,120,140 and 160 kV from X-ray tubes. The X-ray spectra are simulated with the Monte Carlo code Geant4. The EM method is successfully applied to seriously ill-conditioned and under determined estimation problems. The results showed that the X-ray spectrum estimation method is a robust technique for estimating the primary spectrum of X-ray tube, and that the new instrument for transmission measurements can be used to accurately estimate X-ray spectrum.

COSMONAUT: A COmpact spectrometer for measurements of neutrons at the ASDEX upgrade tokamak.

A COmpact Spectrometer for Measurements Of Neutrons at the ASDEX Upgrade Tokamak (COSMONAUT) has been developed for spectroscopy measurements of the 2.45MeV neutron emission from deuterium plasmas at the ASDEX Upgrade. The instrument is based on a CLYC-7 inorganic scintillator, whereby the detection of fusion neutrons occurs via their interaction with 35Cl nuclei in the detector crystal, leading to a peak in the detector response function and providing excellent neutron/gamma-ray discrimination capabilities. The diagnostics is installed along a radial line of sight and makes use of a digital system to record time resolved data for the whole duration of the discharge. Measurements in ASDEX Upgrade plasmas with neutral beam injection have been carried out and are successfully interpreted using state-of-the-art modeling codes. Next step applications of the diagnostics are in experiments aimed at generating energetic particles by ion cyclotron resonance heating schemes. In these scenarios, COSMONAUT will provide unique information on the acceleration of deuterons beyond the beam injection energy and on their confinement, for comparison with modeling.

Potential of Orthosiphon aristatus Blume Miq as Larvicide and Repellent (Review)

Background: The tropical climate in Indonesia can potentially predispose to various diseases caused by mosquitoes, one of which is Dengue Hemorrhagic Fever (DHF). Prevention by eradication of mosquito larvae (with larvicide) and mosquito bites (with repellent) is a strategic countermeasure to control DHF disease vectors. Larvicide and synthetic repellent use also can cause the development of resistance against the larvicide and thereby hurt humans. Therefore, it is necessary to find natural alternatives that are safe and more effective. One plant that has potential as a natural larvicide and repellent is the cat's whisker white-purple variety (Orthosiphon aristatus). The main secondary metabolite groups in white-purple cat whiskers are flavonoids and phenolics, and both groups are thought to have potential as larvicide and repellent. Objective: This review aimed to analyze the potential of white-purple cat plants as larvicides and repellents. Methods: Journal searches in this review came from primary data sources on the internet. Journal searches were conducted using search engines such as Google Scholar, PubMed, and ScienceDirect. In this review, the prediction of the activity of the active compounds in cat's whiskers (sinensetin and rosmarinic acid) as larvicides was also carried out in an in silico study. Results: The rosmarinic acid and sinensetin contained in cat's whiskers plants have the potential as larvicide and repellent Conclusion: Based on the literature search, flavonoid, and phenolic compounds have potential as larvicides and repellent. The larvicide and repellent mechanisms of the two secondary metabolites are of concern because they can cause certain disorders in the central nervous system through skin absorption or breathing

High-performance oxygen terminated synthetic single crystal diamond detector for high gamma dose rate measurement

A high-performance oxygen terminated synthetic single crystal diamond (SCD) detector (4.5 × 4.5 × 0.5 mm3) is presented. The SCD detector exhibits an extremely low leakage current value of 0.29 pA/mm2 with an electric field of 0.3 V/μm. The charge collection spectrum measured with a238Pu source (5.48 MeV α-particles) irradiation shows that the electron and hole charge collection efficiency (CCE) reach as high as 99.1% and 98.9%, with an energy resolution as low as 2.87% and 2.53%, respectively, compared to Si detector. The SCD detector shows excellent radiation hardness and stability under 60Co γ-ray irradiation with a dose rate of 12.737 kGy/h at 150 V bias and is able to withstand a cumulative dose of up to at least 9.3 kGy. The detector output in current mode is linearly related to the dynamic dose rate (0.409 Gy/h-12.737 kGy/h). Similarly, the counting rate of the detector in counting mode exhibits a strong linear variation within the range of 2.6 mGy/h-1269.36 Gy/h. Our results fully indicate that our fabricated SCD detector can be potentially applied to harsh γ irradiation scenarios, which is of guiding significance on real-time dose monitoring.

Modelling Gd-diamond and Gd-SiC neutron detectors

A custom Monte Carlo (MC) computer model was developed to simulate thermal neutron absorption in, and subsequent photon and electron emission from, natural Gd with a view to using the material as a neutron conversion layer for neutron detectors. The MC code also modelled photon and electron detection with two dissimilar detectors: a thick (500 μm) single crystal diamond detector; and a thin (5.15 μm) commercial off the shelf (COTS) 4H–SiC photodiode detector. The detectors’ quantum detection efficiencies (QE) for hard X-rays and γ-rays were relatively low in comparison to their QE for electrons, thus making it possible to collect electron spectra from the Gd layer neutron conversion products which were not overwhelmed by photon emissions from the Gd. The MC code was utilised to determine the optimal thickness of Gd for the efficient detection of a thermal neutron flux. These radiation hard and spectroscopic detectors paired with natural Gd could find utility as robust and compact thermal neutron detectors for nuclear science and engineering, space science, and other applications.

Growth and production of cat's whiskers plant biomass (Orthosiphon aristatus Bl. Miq.) In various accessions and harvest intervals

Cat's whiskers plant is an ornamental plant used as a medicinal plant. The part of the cat's whiskers plant used is leaves. Accessions and harvest intervals are essential for increasing optimal yields to plant biomass growth and results. This study aims to determine the effect of differences in accession, intervals, and interactions between accession differences and intervals on the growth and production of a cat's whiskers biomass. The design used in this study is a complete group design of being randomized with two treatment factors. The first factor has two treatment levels: white flowering accessions (A1) and purple flowering accessions (A2). The second factor is a harvest interval with four treatment levels, namely a 1-week harvest interval (P1), two weeks (P2), three weeks (P3), and six weeks (P4). The results showed that accession treatment significantly affected the number of books, number of branches, flowering ages, leaf fresh weight, leaf dry weight, and leaf simplicia yields. Harvest interval treatment significantly affects the height of the shoots, number of shoots, number of branches, number of leaves, flowering ages, leaf fresh weight, stem fresh weight, flower fresh weight, leaf dry weight, stem dry weight, flower dry weight, and leaf simplicia yield. Accession interactions with harvest intervals significantly affect the height of the shoots, number of shoots, number of branches, number of leaves, flower fresh weight, stem dry weight, and leaf simplicia yields.

Development of diamond detector as fast neutron spectroscopy in the EAST tokamak

We report in this paper the development of the single crystal diamond detector as a fast neutron spectroscopy in the EAST tokamak. The diamond detector is used to detect the fast neutron directly without any neutron converter during the deuterium-deuterium fusion experiment, then the neutron energy spectrum is reconstructed from the recorded continuous scattered spectrum by using a deconvolution algorithm. The results indicate the capability of the diamond spectroscopy which can be used directly to monitor the fast neutron flux and energy spectrum in the EAST tokamak.

A comprehensive calculation of the Primakoff process andthe solar axion flux

The Primakoff process plays a crucial role in axion productionin astrophysical environments and laboratories. Given the rising interestin axion physics and many on-going experimental activities, we conducta comprehensive calculation of this process and carefully examineseveral aspects that have been neglected in the literature. In particular,our calculation is valid for axions with significantly large masses,which would be of importance to axion searches utilizing crystal andliquid xenon detectors. We present the most updated calculation ofthe Primakoff solar axion flux, with a simple parametrization thatis applicable to a broad range of axion masses up to a few tens ofkeV. Our code is publicly available at GitHub.

Improved modeling of detector response effects in phonon-based crystal detectors used for dark matter searches

Improved modeling of detector response effects in phonon-based crystal detectors used for dark matter searches

Combining PET and Compton imaging with edge-on CZT detectors for enhanced diagnostic capabilities

The key metrics for positron emission tomography (PET) imaging devices include the capability to capture the maximum available amount of annihilation photon information while generating high-quality images of the radiation distribution. This capability carries clinical implications by reducing scanning time for imaging, thus reducing radiation exposure for patients. However, imaging quality is degraded by positron range effects and the non-collinearity of positron annihilation photons. Utilizing an edge-on configuration of cadmium zinc telluride (CZT) detector crystals offers a potential solution to increase PET sensitivity. The high cross-section of CZT and its capacity to detect both 511 keV annihilation gammas and high-energy prompt gammas, along with multiple photon interaction events, contribute to this increased sensitivity. In this study, we propose a dual-panel edge-on CZT detector system comprised of 4 &amp;times; 4 &amp;times; 0.5 cm3 CZT detectors, with panel dimensions of 20 &amp;times; 15 cm2 and a thickness of 4 cm. In this study, we demonstrate the increased sensitivity of our imaging system due to the detection of the Compton kinematics of high-energy gammas originating from prompt-gamma-emitting isotopes. This was achieved using Monte Carlo simulations of a prompt-gamma-emitting isotope,72As, with mean positron ranges &gt;3 mm. Our system&amp;rsquo;s dynamic energy range, capable of detecting gammas up to 1.2 MeV, allows it to operate in a dual-mode fashion as both a Compton camera (CC) and standard PET. By presenting reconstructions of 72As, we highlight the absence of positron range effects in CC reconstructions compared to PET reconstructions. In addition, we evaluate the system&amp;rsquo;s increased sensitivity resulting from its ability to detect high-energy prompt gammas.

Simultaneous measurements for fast neutron flux and tritium production rate using pulse shape discrimination and single crystal CVD diamond detector

This paper presents the development of a simultaneous measurement method for fast neutron energy spectra and tritium production rates within mixed radiation fields using a single crystal chemical vapour deposition diamond detector combined with a lithium fluoride (LiF) foil. The method involves the separation of pulses with rectangular shapes and the determination of the depth position within the single crystal diamond (SCD) struck by fast neutrons or nuclear reaction products including recoil tritons from the LiF foil based on pulse width, extracting pulse events occurred at the specific bulk region and the surface region of the SCD. Subsequently, unfolding techniques were employed to analyse the energy deposition spectrum of pulses at the specific bulk region which are induced only by fast neutrons, allowing the deduction of the fast neutron energy spectrum. To evaluate the tritium production rate, the energy deposition spectrum of pulses from events occurring at the SCD surface facing the LiF foil was analysed. By estimating the energy deposition spectrum solely induced by fast neutrons striking the SCD surface and subtracting it from the energy deposition spectrum of events at the SCD surface, the contribution of energetic ions, such as recoil tritons generated by the 6Li(n,α)3H reaction in the LiF foil, was determined. The fast neutron flux and tritium production rate obtained through this study were consistent with particle transport calculations, demonstrating the successful development of a method suitable for performance testing of fusion reactor blankets.