Thin Detectors Research Articles

ON IONIZATION LOSS DISTRIBUTION OF RELATIVISTIC PARTICLES IN THIN DETECTORS

Ionization energy loss distribution of high-energy charged particles in thin detectors is considered. Its modification due to the fact that a part of δ-electrons, kicked out from the atoms by the incident particles, escape from the detector and do not dispose of all their kinetic energy inside it, is estimated and shown to be negligibly small. The physical reasons for this are discussed. The parameters responsible for the magnitude of this modification are obtained.

Real-Time Radiation Beam Monitoring by Flexible Perovskite Thin Film Arrays.

Real-time and in-line transversal monitoring of ionizing radiation beams is a crucial task for several applications which span from medical treatments to particle accelerators in high energy physics. Here a flexible and large area device based on 2D hybrid perovskite thin films (phenylethylammonium lead bromide), fabricated onto a thin flexible polyimide substrate, able to map the transversal beam profile of high energy radiation beams is reported. The performance of this novel tool is here compared with the one offered by standard commercial large-area technology, namely radiochromic sheets. The great potential of this class of devices is demonstrated by successfully mapping in real-time a 5 MeV proton beam at fluxes between 108 and 1010 H+ s-1 cm-2, confirming the capability to operate in a radiation-harsh environment without output signal saturation issues. The versatility and scalability of here proposed detecting system are demonstrated by the development of a multipixel array able to map in real-time a 40 kVp X-ray beam spot (dose rate 8 mGy s-1). Perovskite thin film-based detectors are thus assessed as a very promising class of thin, flexible devices for real-time, in-line, large-area, conformable, reusable, transparent, and low-cost transversal beam monitoring of different ionizing radiation.

Alloy engineered cryotronically stable polymorphic strained photo detector functionalized by palladium enriched tin diselenide nanosheets

Scientists experience formidability in developing an advanced materials capable to withstand extreme environmental circumstances without sacrificing its fundamental properties. In this realm, solid-state devices utilizing 'metal dichalcogenide' materials offer significant advantages for cryogenic purposes, but rarely explored. In this study, thin film photodetectors (TFPDs) based on meta-materials of PdxSn1−xSe2 (x=0.0, 0.2, 0.5) nanosheets are introduced. Nanosheets are extracted from bulk via sonochemical exfoliation to fabricate TFPDs. Novel material Pd0.5Sn0.5Se2 grown by 50 % palladium enrichment in SnSe2 exhibits polymorphism comprising structural duality of hexagonal-orthorhombic phases. TFPDs based on PdxSn1−xSe2 (x=0.0, 0.2, 0.5) nanosheets display substantial photoresponse in which TFPD functionalised by Pd0.5Sn0.5Se2 nanosheets portrays superior photodetection. Raman peak demonstrates notable thermal-sensing through blue-shifting and sharpening under cryogenic-temperatures. Surprisingly, Pd0.5Sn0.5Se2 nanosheets based TFPD reveals considerable photodetection, achieving 0.52 mAW−1 responsivity at 10 K cryogenic-temperature. To the best of our knowledge, present investigation surpasses previous reports, highlighting a thin film-based photo detector that represents exceptional responsivity at 10 K cryogenic-temperature reported by us for the first time. As an outcome of present study, a TFPD based on Pd0.5Sn0.5Se2 nanosheets emerges as advanced cryotronic material for designing next-generation cryogenic photonic devices due to its higher steadiness, excellent reproducibility and operational efficiency at cryogenic-temperature of 10 K.

From crude oil to bitumen: Genetic variability in chemistry and its influence on viscoelastic of binders

The chemical composition and properties of bitumen are derived from crude oil, which directly influences its viscoelastic properties. Six different crude oil sources were examined to explore how crude oil characteristics impact bitumen. The bitumen was produced through in-house atmospheric decompression distillation, and aging tests were conducted on these samples. The chemical properties of the crude oils, virgin binders, and aged binders were analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Additionally, the separation and quantitative analysis of saturates, aromatics, resins, and asphaltenes (SARA) in crude oil and bitumen binders were carried out using Thin Layer Chromatography-Flame Ionization Detector (TLC-FID). Sweep tests on binders were conducted using a Dynamic Shear Rheometer (DSR). Master curves were created based on the CAM model and the 2S2P1D model to assess the dynamic viscoelastic properties of bitumen. The grey correlation method was employed to examine how bitumen chemical composition and properties affect its viscoelasticity. Results indicated that crude oil profoundly influences bitumen's chemical composition and properties. The functional group index and component content of bitumen are inherited from crude oil and are closely linked to the corresponding indices of crude oil. The functional group index, SARA, and colloidal stability coefficients of bitumen are intimately connected to the viscoelastic parameters of bitumen. The impact of the functional group index on the viscoelastic parameters is more pronounced than that of SARA content. This insight is crucial for guiding the selection of oil sources in bitumen production processes.

Preparation of Sn-Doped Ga2O3 Thin Films and MSM Ultraviolet Detectors Using Magnetron Co-Sputtering.

Sn-doped Ga2O3 thin films and metal-semiconductor-metal (MSM) ultraviolet detectors were prepared using the co-sputtering method to enhance their photoelectric performance. The results revealed that Sn doping can effectively change the optical and electrical properties of thin films, greatly improving the photoelectric responsiveness of the devices. Through microstructure testing results, all of the thin film structures were determined to be monoclinic beta phase gallium oxide. At a DC power of 30 W, the thickness of the Sn-doped thin film was 430 nm, the surface roughness of the thin film was 4.94 nm, and the carrier concentration, resistivity, and mobility reached 9.72 × 1018 cm-3, 1.60 × 10-4 Ω·cm, and 45.05 cm3/Vs, respectively. The optical results show that Sn doping clearly decreases the transmission of thin films and that the bandgap can decrease to 3.91 eV. Under 30 W DC power, the photo dark current ratio of the detector can reach 101, time responses of tr = 31 s and tf = 22.83 s were obtained, and the spectral responsivity reached 19.25 A/W.

The ATLAS experiment at the CERN Large Hadron Collider: a description of the detector configuration for Run 3

The ATLAS detector is installed in its experimental cavern at Point 1 of the CERN Large Hadron Collider. During Run 2 of the LHC, a luminosity of ℒ = 2 × 1034 cm-2 s-1 was routinely achieved at the start of fills, twice the design luminosity. For Run 3, accelerator improvements, notably luminosity levelling, allow sustained running at an instantaneous luminosity of ℒ = 2 × 1034 cm-2 s-1, with an average of up to 60 interactions per bunch crossing. The ATLAS detector has been upgraded to recover Run 1 single-lepton trigger thresholds while operating comfortably under Run 3 sustained pileup conditions. A fourth pixel layer 3.3 cm from the beam axis was added before Run 2 to improve vertex reconstruction and b-tagging performance. New Liquid Argon Calorimeter digital trigger electronics, with corresponding upgrades to the Trigger and Data Acquisition system, take advantage of a factor of 10 finer granularity to improve triggering on electrons, photons, taus, and hadronic signatures through increased pileup rejection. The inner muon endcap wheels were replaced by New Small Wheels with Micromegas and small-strip Thin Gap Chamber detectors, providing both precision tracking and Level-1 Muon trigger functionality. Trigger coverage of the inner barrel muon layer near one endcap region was augmented with modules integrating new thin-gap resistive plate chambers and smaller-diameter drift-tube chambers. Tile Calorimeter scintillation counters were added to improve electron energy resolution and background rejection. Upgrades to Minimum Bias Trigger Scintillators and Forward Detectors improve luminosity monitoring and enable total proton-proton cross section, diffractive physics, and heavy ion measurements. These upgrades are all compatible with operation in the much harsher environment anticipated after the High-Luminosity upgrade of the LHC and are the first steps towards preparing ATLAS for the High-Luminosity upgrade of the LHC. This paper describes the Run 3 configuration of the ATLAS detector.

Investigation of Deconvolution Method with Adaptive Point Spread Function Based on Scintillator Thickness in Wavelet Domain.

In recent years, indirect digital radiography detectors have been actively studied to improve radiographic image performance with low radiation exposure. This study aimed to achieve low-dose radiation imaging with a thick scintillation detector while simultaneously obtaining the resolution of a thin scintillation detector. The proposed method was used to predict the optimal point spread function (PSF) between thin and thick scintillation detectors by considering image quality assessment (IQA). The process of identifying the optimal PSF was performed on each sub-band in the wavelet domain to improve restoration accuracy. In the experiments, the edge preservation index (EPI) values of the non-blind deblurred image with a blurring sigma of σ = 5.13 pixels and the image obtained with optimal parameters from the thick scintillator using the proposed method were approximately 0.62 and 0.76, respectively. The coefficient of variation (COV) values for the two images were approximately 1.02 and 0.63, respectively. The proposed method was validated through simulations and experimental results, and its viability is expected to be verified on various radiological imaging systems.

Monitoring of carbon ion therapeutic beams with thin silicon sensors

Single ion counting in particle therapy may lead to new beam monitoring systems, enabling innovative delivery strategies that are faster and more sensitive than those currently used in clinics. Previous studies carried out by the University and the National Institute of Nuclear Physics (INFN) of Turin have demonstrated the feasibility of using thin silicon detectors to count single protons in clinical beams. The aim of this work is to report the performance of a strip-segmented 60-μm thick silicon PIN sensor used for single carbon ion discrimination. All measurements were performed using the CNAO synchrotron at different beam energies covering the clinical energy range (115–399 MeV/u). Signals from the sensor strips were read using a custom amplifier board and sampled with a 5 GS/s digitizer. The carbon ion signals were analyzed in terms of amplitude, duration, and deposited charge at different sensor bias voltages.

High-energy electron measurements with thin Si detectors

A technique for measuring high-energy electrons using Si detectors of various thicknesses that are much smaller than the range of the examined electrons is presented. The advantages of the method are discussed on the basis of electron–positron pair creation recently studied in deuteron–deuteron fusion reactions at very low energies. Careful Geant4 Monte Carlo simulations enabled to identify the main spectral contributions of emitted electrons and positrons resulting from the energy loss mechanisms and scattering processes within the target, detector and their holders. Significant changes in the intensity of the detected electrons, depending on the detector thickness and the thicknesses of absorption foils placed in the front of the detector could be observed. The corresponding correction factors have been calculated and can be used for different applications in basic and applied research.

Energy painting: helium-beam radiography with thin detectors and multiple beam energies

Objective. Compact ion imaging systems based on thin detectors are a promising prospect for the clinical environment since they are easily integrated into the clinical workflow. Their measurement principle is based on energy deposition instead of the conventionally measured residual energy or range. Therefore, thin detectors are limited in the water-equivalent thickness range they can image with high precision. This article presents our energy painting method, which has been developed to render high precision imaging with thin detectors feasible even for objects with larger, clinically relevant water-equivalent thickness (WET) ranges. Approach. A detection system exclusively based on pixelated silicon Timepix detectors was used at the Heidelberg ion-beam therapy center to track single helium ions and measure their energy deposition behind the imaged object. Calibration curves were established for five initial beam energies to relate the measured energy deposition to WET. They were evaluated regarding their accuracy, precision and temporal stability. Furthermore, a 60 mm × 12 mm region of a wedge phantom was imaged quantitatively exploiting the calibrated energies and five different mono-energetic images. These mono-energetic images were combined in a pixel-by-pixel manner by averaging the WET-data weighted according to their single-ion WET precision (SIWP) and the number of contributing ions. Main result. A quantitative helium-beam radiograph of the wedge phantom with an average SIWP of 1.82(5) % over the entire WET interval from 150 mm to 220 mm was obtained. Compared to the previously used methodology, the SIWP improved by a factor of 2.49 ± 0.16. The relative stopping power value of the wedge derived from the energy-painted image matches the result from range pullback measurements with a relative deviation of only 0.4 %. Significance. The proposed method overcomes the insufficient precision for wide WET ranges when employing detection systems with thin detectors. Applying this method is an important prerequisite for imaging of patients. Hence, it advances detection systems based on energy deposition measurements towards clinical implementation.

First measurements with a new β-electron detector for spectral shape studies

The shape of the electron spectrum emitted in β decay carries a wealth of information about nuclear structure and fundamental physics. In spite of that, few dedicated measurements have been made of β-spectrum shapes. In this work we present a newly developed detector for β electrons based on a telescope concept. A thick plastic scintillator is employed in coincidence with a thin silicon detector. The first measurements employing this detector have been carried out with mono-energetic electrons from the high-energy resolution electron-beam spectrometer at Bordeaux. Here we report on the good reproduction of the experimental spectra of mono-energetic electrons using Monte Carlo simulations. This is a crucial step for future experiments, where a detailed Monte Carlo characterization of the detector is needed to determine the shape of the β-electron spectra by deconvolution of the measured spectra with the response function of the detector. A chamber to contain two telescope assemblies has been designed for future β-decay experiments at the Ion Guide Isotope Separator On-Line facility in Jyväskylä, aimed at improving our understanding of reactor antineutrino spectra.

Plasmon enhanced luminescence of Tb/Eu co-doped film by Au NRs-PVA nanocomposite film.

Plasmonic nanostructures have great potential for improving the radiation properties of emitters. Here, the plasmonic Au nanorods-PVA nanocomposite films are used to uniformly improve the photoluminescence of Tb/Eu co-doped PMMA film within the local micro-region. Under the excitation of 292 nm, the maximum enhancement factor is 37.2-fold for emission at 612 nm and 21.6-fold for emission at 545 nm. Moreover, the finite different time domain simulations are developed to further explain the experimental results. It is indicated that the modulation of luminescence can be attributed to the increase of the local density of optical states through the Purcell effect and the improvement of the energy transfer efficiency between Tb and Eu. Under the excitation of 360 nm, the maximum enhancement factor is about 71.5-fold. In this case, the Au nanorods are mainly used for modulating the emission process at 612 nm, which deduced a greater enhancement factor at 612 nm. This study provides a deep understanding of the interactions between rare earth ions co-doped materials and plasmonic nanostructures, building a bridge to fabricate a useful platform for several applications, such as thin film-based detectors and sensors.

Optimization Method to Predict Optimal Noise Reduction Parameters for the Non-Local Means Algorithm Based on the Scintillator Thickness in Radiography.

The resulting image obtained from an X-ray imaging system depends significantly on the characteristics of the detector. In particular, when an X-ray image is acquired by thinning the detector, a relatively large amount of noise inevitably occurs. In addition, when a thick detector is used to reduce noise in X-ray images, blurring increases and the ability to distinguish target areas deteriorates. In this study, we aimed to derive the optimal X-ray image quality by deriving the optimal noise reduction parameters based on the non-local means (NLM) algorithm. The detectors used were of two thicknesses (96 and 140 μm), and images were acquired based on the IEC 62220-1-1:2015 RQA-5 protocol. The optimal parameters were derived by calculating the edge preservation index and signal-to-noise ratio according to the sigma value of the NLM algorithm. As a result, a sigma value of the optimized NLM algorithm (0.01) was derived, and this algorithm was applied to a relatively thin X-ray detector system to obtain appropriate noise level and spatial resolution data. The no-reference-based blind/referenceless image spatial quality evaluator value, which analyzes the overall image quality, was best when using the proposed method. In conclusion, we propose an optimized NLM algorithm based on a new method that can overcome the noise amplification problem in thin X-ray detector systems and is expected to be applied in various photon imaging fields in the future.

Test of 116CdWO4 and Li2MoO4 scintillating bolometers in the CROSS underground facility with upgraded detector suspension

In preparation for the CROSS experiment to search for double-beta (2β) decay of 100Mo, we upgraded a low-background facility at the Canfranc underground laboratory (Spain) by installing a magnetic damping-based detector suspension inside a pulse-tube cryostat. We tested the suspension in low-temperature (15 mK) measurements with two scintillating bolometers made of large-volume crystals of 116CdWO4 (reference of the set-up) and Li2MoO4 (R&D of the CLYMENE project in view of the CUPID 2β experiment), each coupled to a thin Ge bolometric light detector. Despite the evidence of a residual pulse-tube-induced noise, picked up by cabling, we achieved high performance with all tested devices. In particular, the energy resolution for 2615 keV γ-ray measured with both 116CdWO4 and Li2MoO4 bolometers is ∼6 keV FWHM, among the best-reported results for thermal detectors based on such compounds representing a great interest to searches for 2β decay in 116Cd (Q-value is 2813 keV) and 100Mo (3034 keV) respectively. Highly efficient particle identification (α vs. β/γ) is achieved also with the scintillating bolometer made of a low light yield crystal (Li2MoO4), thanks to the low noise (10 eV RMS) exhibited by the light detector exploiting the Neganov-Trofimov-Luke effect for signal amplification. We also found a rather high level of radiopurity in the Li2MoO4 crystal; only traces of 210Po and 226Ra were detected (∼0.1 mBq/kg each), while the 228Th activity is expected to be at least an order of magnitude lower, as well as a 40K activity is below 6 mBq/kg.

The Migration of Organic Chlorine Pesticide Residues in the Composition of the Soil Samples from Mirzaabad, Gulistan and Boyovut Districts of Syrdarya Region

The thin layer chromatography gas chromatography ECD detector was employed to evaluate soil samples and wheat stalks collected during the spring season for the presence of chlorine organic pesticides, namely DDT, DDE, DDD, HCH alpha, and gamma isomers. The study revealed that the uppermost concentration of pesticides is constrained within the depth interval of 0–10(20) cm, with their infiltration extending to a depth of 2.0–2.5 m. The initial investigation focused on examining the dynamics and movement of OCP, including substances such as DDT, DDD, DDE, alpha HCH, and gamma HCH, throughout the Syrdarya region. This page provides an overview of organochlorine pesticides, their residual presence, their application in agricultural regions, and the constituent makeup of wheat stalks. In April 2023, a collection of samples was obtained from several districts within the Syrdarya region. Subsequently, a comprehensive analysis was conducted on a total of 15 samples. The gas chromatography technique with an electron capture detector (GC/ECD) was employed for the investigation of organic chlorine insecticides. The isolation and quantification of organic chlorine insecticides with low to medium polarity were achieved using a capillary column.

New vertex reconstruction algorithm for measuring gamma-rays with the AMS tracker

Gamma-ray polarization is one of the most promising tools to probe the universe at extreme conditions and search for new physics. The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station. With its high accuracy thin silicon strip detectors and permanent magnet, AMS is unique to study the polarization of high energy gamma-rays. The detection of gamma-rays above a few hundreds of MeV typically utilize the electron–positron pair production process, and the key step is to reconstruct the vertex where gamma-ray converts into the electron–positron pair. We present a new vertex reconstruction algorithm that is based on an extended cellular automaton to determine the direction and energy information of gamma-rays from the electron and positron trajectories in the AMS tracker. The vertex reconstruction efficiency is significantly improved with the presented algorithm over the entire energy range above 100 MeV and reaches >90% above 1 GeV. The fake rate is drastically reduced over the entire energy range and is reduced from ∼10% to ∼3% at 200 MeV. The presented algorithm will thus provide the basis for measuring gamma-ray polarization with AMS.

Characteristics of thin p-MCz Si Microstrip Detector Irradiated upto a mixed fluence of 1017neq./cm2for the FCC

Silicon microstrip detectors can be used for the precise particle tracking in the inner tracking region of the detector used in the future high luminosity collider experiment. In the future experiments, hadron collider provides higher luminosities on the strip detector, and therefore, a detector requires very high radiation hardness. Within CERNRD50collaboration, MCz Si is identified as a prime radiation hard material for the fabrication of the p-Si microstrip detector. In this paper, we have used the experimentally verified four level deep-trap mixed irradiation model for p-MCz Si to investigate the effect of heavy irradiations up to a mixed fluence of 1017n eq./cm2 on the full depletion voltage, leakage current, and charge collection efficiency using SRH and CCE modelling.The changes in the characteristics were evaluated, and effect of the traps on the macroscopic performance of the detectors and possible improvement in the design and semiconductor technology of the p-Mcz silicon microstrip detector.

Application of graphene gas sensor technological convergence PSO-SVM in distribution transformer insulation condition monitoring and fault diagnosis

This study aims to improve the real-time monitoring and fault diagnosis of distribution transformers by utilizing a combination of five thin film gas detectors, these detectors include metal-modified graphene composite films and SnO2/RGO humidity sensors, which were prepared using the hydrothermal method. The experiment focused on investigating humidity and main fault characteristic gases that can reflect the insulation status of transformers. Additionally, a gas sensor array was constructed using a deep confidence neural network model. Based on the analysis of dissolved gas in transformer oil, the study extensively discusses the insulation fault diagnosis model and constructs the transformer fault diagnosis model using various methods including TRM, Particle swarm optimization support vector machine. The results demonstrated that the SnO2/RGO thin film humidity sensor exhibited high humidity sensitivity, and the other thin film gas sensors also exhibited good sensitivity. The average accuracy of the three classification methods mentioned is 80%, 92%, and 96%, respectively. These findings highlighted that the vector machine model not only improved the fault diagnosis accuracy but also possessed the characteristics of fewer parameters and a fast rate of convergence. Consequently, it effectively addressed the issue of early diagnosis of potential transformer faults. This study was of significant practical importance for ensuring the secure operation of the power grid.

Analysis of absorption signal and noise in thin phosphor detectorsfor high-energy transmission radiography

We investigated the detective quantum efficiency (DQE) of thin gadoliniumoxysulfide phosphor-based flat-panel detectors (FPDs) using cascaded-systemsanalysis and Monte Carlo (MC) simulations for applications in megavoltage(MV) x-ray industrial imaging. We decomposed the DQE formula into(dose-independent) upper-limit DQE and (dose-dependent) DQE-reductionfactors. We obtained the absorbed energy distributions (AEDs) forvarious x-ray detector designs and photon energies using MC simulationsand applied the AED analysis to the DQE formula. The investigationsexamined include the x-ray-detector-only DQE and the effect of thecoupling efficiency between the x-ray detector and readout panel,including electronic noise, on the upper-limit DQE. This study confirmsthat the design of the metal build-up layer on the phosphor is effectivefor MV imaging and emphasizes the importance of designing the readoutpanel to maintain the upper-limit DQE. We expect the proposed DQEanalysis to be suitable for designing and evaluating FPDs for high-energynondestructive x-ray testing.

Study of Proton Radiation Damage Effects in Si microstrip Detector for New and Fast Tracking System of pCT

A new and fast radiation hard p-Si micro strip detector requires for the high proton imaging performance using the Proton Computed Tomography (pCT) system. Silicon trackers of the pCT have been measured the actual proton dose delivered to the cancer patient during the medical treatment. In this paper, several proton cancer doses up to 9.62x 1014 neq,/cm2 are used for the SRH modelling of the full depletion voltage and leakage current at 293 K of the Si micro-strip detector using microscopic radiation damage model. Radiation hard thin (150μm) p-type MCz Si micro strip detector design is proposed for the pCT that can work up to 800V for very high-irradiated proton cancer doses.