Detector Design Research Articles

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.

TCAD Simulation of X-ray irradiated Si microstrip detector : Impact on full depletion voltage and leakage current

In the intense x-ray radiation environment at synchrotron sources, it is reported that the performance of the silicon pixel detectors degrades with an increasing x-ray dose up to 10 MGy. To study the impact of x-ray irradiation effects in the n-Fz Si microstrip detector, the microscopic radiation damage parameters of x-ray radiation were extracted from the current–voltage, and capacitance-voltage experiments on test Si microstrip detector. The damage parameters are implemented in Synopsys TCAD. In this paper, we have irradiated the test structure up to 10 MGy, and the results on full depletion voltage, and leakage current are compared with the TCAD simulation results. A very good agreement in between experimental and simulation results is observed in the leakage current for the non-irradiated, and 1 MGy irradiated detectors, where for high doses up to 10 MGy, experimental leakage current was fifty times higher than the simulated leakage current at full depletion voltage. The full depletion voltage in 0 MGy detector is also well matched with the simulation result, and further, it shows the full depletion voltage performance of x-ray irradiated detector. Finally, the new detector design specifications and process parameters are proposed for the optimum performance of the radiation hard p+n Si pixel detector equipped with guard rigs at cut edge for the next generation photon science applications.

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.

A Study on the Relation Between Voltage and Bilirubin Concentration in Artificial Blood Solution by Bilirubin Detector

This research project focuses on investigating the correlation between electric potential difference and bilirubin concentration within an artificial blood solution, utilizing the principles of light absorption. The bilirubin detector's design and construction incorporate a blue light source with a 460 nm wavelength and a green light source with a 560 nm wavelength, enabling interaction with bilirubin concentrations ranging from 2 to 14 mg/dl. Analysis of the project's outcomes revealed a direct relationship between the bilirubin detector's output voltage and the concentration of the bilirubin solution. Notably, an interaction with bilirubin was observed at the 460 nm wavelength, influencing light absorption. In cases of higher bilirubin concentration, light transmittance was diminished, leading to a heightened voltage difference. Conversely, lower bilirubin concentrations facilitated increased light transmission, resulting in a reduced voltage difference. This study contributes to a comprehensive understanding of bilirubin detection methodologies and their potential applications in medical diagnostics.

Scalable Detector Design for a High-Resolution Fast-Neutron Radiography Panel

Development of a scalable flat-panel neutron radiography device is needed to meet the nondestructive testing needs of a growing industrial market. Flood field images from a Cs-137 gamma source and a Cf-252 fission neutron source were generated using a detector composed of a 3-mm-thick sheet of EJ-200, and 3-mm-thick sheet of acrylic light spreader, an 8 times 8 array of SensL MICROFJ-60035-TSV SiPMs, and an IDEAS ROSSPAD readout module. The readout module can be tiled together with similar systems to create a panel of any size, and is only limited by the number of available Ethernet ports in a switching system. A collimated gamma line image demonstrated a 90% spatial resolution of approximately 0.47 line pairs per centimeter and a 10% spatial resolution of approximately 2.32 line pairs per centimeter. A neutron edge image demonstrated a 90% spatial resolution of approximately 0.70 line pairs per centimeter and a 10% spatial resolution of approximately 3.35 line pairs per centimeter. Both of these images show the ability to generate radiographs with sub-SiPM spatial resolution. Using these readout modules, a large-scale radiographic panel can be developed by tiling ROSSPAD modules together.

Detector system challenges of the wide‐field spectroscopic survey telescope (WST)

AbstractThe wide‐field spectroscopic survey telescope (WST) is proposed to become the next large optical/near infrared facility for the European southern observatory (ESO) once the extremely large telescope (ELT) has become operational. While the latter is optimized for unprecedented sensitivity and adaptive‐optics assisted image quality over a small field of view, WST addresses the need for large survey volumes in spectroscopy with the light‐collecting power of a 10‐m class telescope. Its unique layout will feature the combination of multi‐object and integral field spectroscopy simultaneously. For the intended capacity of this layout, a very large number of detectors are needed. The complexity of the detector systems presents a number of challenges that are discussed with a focus on novel approaches and innovative detector designs that can be expected to emerge over the anticipated 20‐year timeline of this project.

Monte Carlo analyses and experimental investigation of the vanadium self-powered neutron detector in 60Co source and research pulsed reactor

As the online monitoring apparatus in the reactor, self-powered neutron detectors (SPNDs) have a great potential for development in nuclear energy. To further characterize the SPND response in the actual radiation field, some irradiation experiments and Monte Carlo analyses based on the 60Co gamma-rays source and a research pulsed reactor were performed. During the experiments, the current signals were measured with various reactor irradiation facilities. A series of experimental phenomena, such as the negative current effect of the gamma rays, shutdown attenuation current, and the difference in detector sensitivity, are described and theoretically explained by using a numerical model GEANT4-SPND, an in-house Monte Carlo toolkit for SPND simulation based on Geant4. The numerical model proves to be highly effective in restoring the experimental results for the detector response current, the signal prompt proportion, and the current trend. This work has not only validated the existing calculation method but also provided reference radiation field parameters and detector experimental data for the future development and verification of sensor models. Besides, the analyses results have provided some insights into the study of the mechanism and optimization of detector design.

Spektr–UF Mission Spectrograph Space Qualified CCD Detector Subsystem

Spektr–UF (World Space Observatory Ultraviolet, WSO-UV) is a Russian-led international collaboration aiming to develop a large space-borne 1.7 m Ritchey–Chretién telescope with science instruments to study the Universe in ultraviolet wavelengths. The WSO-UV spectrograph (WUVS) consists of three channels: two high-resolution channels (R = 50,000) with spectral ranges of 115–176 nm and 174–310 nm, and a low-resolution (R = 1000) channel with a spectral range of 115–305 nm. Each of the three channels has an almost identical custom detector consisting of a CCD inside a vacuum enclosure, and drive electronics. The main challenges of the WUVS detectors are to achieve high quantum efficiency in the FUV-NUV range, to provide low readout noise (3 e− at 50 kHz) and low dark current (<12 e−/pixel/hour), to operate with integral exposures of up to 10 h and to provide good photometric accuracy. A custom vacuum enclosure and three variants of a custom CCD272-64 sensor with different UV AR coatings optimised for each WUVS channel were designed. The enclosure prevents contamination and maintains the CCD at the operating temperature of −100 ∘C, while the temperature of the WUVS optical bench is +20 ∘C. A camera electronics box (CEB) that houses the CCD drive electronics was developed. Digital correlated double sampling technology allows for extremely low readout noise and flexible frequency for normal and binned pixel readout modes. This paper presents the WUVS detector design drivers, methods for extending the service life of the CCD sensors working with low signals in a space radiation environment and the key calculated parameters and results of the engineering qualification model qualification campaign.

Monte Carlo model of a prototype flat-panel detector for multi-energy applications in radiotherapy.

The incorporation of multi-energy capabilities into radiotherapy flat-panel detectors offers advantages including enhanced soft tissue visualization by reduction of signal from overlapping anatomy such as bone in 2D image projections; creation of virtual monoenergetic images for 3D contrast enhancement, metal artefact reduction and direct acquisition of relative electron density. A novel dual-layer on-board imager offering dual energy processing capabilities is being designed. As opposed to other dual-energy implementation techniques which require separate acquisition with two different x-ray spectra, the dual-layer detector design enables simultaneous acquisition of high and low energy images with a single exposure. A computational framework is required to optimize the design parameters and evaluate detector performance for specific clinical applications. In this study, we report on the development of a Monte Carlo (MC) model of the imager including model validation. The stack-up of the dual-layer imager (DLI) was implemented in GEANT4 Application for Tomographic Emission (GATE). The DLI model has an active area of 43×43 cm2 , with top and bottom Cesium Iodide (CsI) scintillators of 600 and 800μm thickness, respectively. Measurement of spatial resolution and imaging of dedicated multi-material dual-energy (DE) phantoms were used to validate the model. The modulation transfer function (MTF) of the detector was calculated for a 120 kVp x-ray spectrum using a 0.5mm thick tantalum edge rotated by 2.5o . For imaging validation, the DE phantom was imaged using a 140 kVp x-ray spectrum. For both validation simulations, corresponding measurements were done using an initial prototype of the imager. Agreement between simulations and measurement was assessed using normalized root mean square error (NRMSE) and 1D profile difference for the MTF and phantom images respectively. Further comparison between measurement and simulation was made using virtual monoenergetic images (VMIs) generated from basis material images derived using precomputed look-up tables. The MTF of the bottom layer of the dual-layer model shows values decreasing more quickly with spatial frequency, compared to the top layer, due to the thicker bottom scintillator thickness and scatter from the top layer. A comparison with measurement shows NRMSE of 0.013 and 0.015 as well as identical MTF50 of 0.8 mm1 and 1.0 mm1 for the top and bottom layer respectively. For the DE imaging of the DE-phantom, although a maximum deviation of 3.3% is observed for the 10mm aluminum and Teflon inserts at the top layer, the agreement for all other inserts is less than 2.2% of the measured value at both layers. Material decomposition of simulated scatter-free DE images gives an average accuracy in PMMA and aluminum composition of 4.9% and 10.3% for 11-30mm PMMA and 1-10mm aluminum objects respectively. A comparison of decomposed values using scatter containing measured and simulated DE images shows good agreement within statistical uncertainty. Validation using both MTF and phantom imaging shows good agreement between simulation and measurements. With the present configuration of the digital prototype, the model can generate material decomposed images and virtual monoenergetic images.

The potential of a TeV-scale muon-ion collider

We propose the development of a novel muon-proton and muon-nucleus collider facility at the TeV scale that is capable of performing precision deep inelastic scattering measurements in new regimes and providing a rich program in nuclear and particle physics. Such a facility could seed, or leverage, the development of a muon-antimuon collider and make use of the existing hadron accelerator infrastructure when sited at a facility such as Brookhaven National Laboratory, Fermilab, or CERN. We discuss the possible energy and luminosity design parameters for several collider configurations, and illustrate the science potential with several studies on deep inelastic scattering kinematics, Higgs and vector boson production, top quark production, and beyond Standard Model leptoquark production. Detector design considerations and a possible road map toward development are also given.

Design and Evaluation of a Near-Sensor Magneto-Electric FET-Based Event Detector

Design and Evaluation of a Near-Sensor Magneto-Electric FET-Based Event Detector

Spectroscopy at LHCb: experimental overview

The large dataset collected in proton-proton collisions at the LHC allows precision studies and discovery of new states in the field of conventional and exotic heavy-hadron spectroscopy; both are crucial to understand QCD dynamics and binding rules. This is possible due to high luminosity, high b/c-hadron production cross-section and the unique, dedicated design of the LHCb detector, optimised to reconstruct b/c-hadron decays. The latest results on conventional and exotic spectroscopy from LHCb are presented.

An Improved Design of Absolute-value Detector by Using Optimized Ripple Adder

Absolute-value detector (AVD) is one of the most basic bit-operating devices, which compares the magnitude of two inputs. However, the traditional 4-bit AVD is not only time-consuming but also has a high energy consumption. This paper uses a hybrid design to optimize the 4-bit AVD by introducing an improved ripple adder in the absolute value extraction part, which then can be less energy-consuming and requires fewer transistors. The paper divides the design of AVD into an absolute value extraction part and a comparator. The input (2’s complement) can be positive or negative numbers in the absolute value extraction part. By observing the most significant bit (MSB) of the input, the design can determine the sign of input and output magnitude. For the comparator, this paper uses a logic of step-by-step comparison from the most to the least significant bits. Then, this paper finds the minimum delay of the design by critical path analysis and gate sizing. The final delay is set at 1.5 times its minimum. Device voltage optimization is applied for calculating the energy consumption. Finally, with 1.5 times the minimum delay, the energy consumption is 40% less than the consumption when the delay is the minimum.

Design of magnetic flux leakage detector for mine wire rope

At present, the online detection technology of wire rope damage in coal mine hoisting needs to be improved. Given the large number of detection elements and high detection cost in the wire rope detection device, the magnetic flux leakage detection device of the wire rope damage detection system is designed. The magnetic sensor is selected. At the same time, in order to improve the strength of the magnetic leakage field at the defect and reduce the number of magnetic sensors, a magnetic focusing device is designed. The finite element simulation shows that the magnetic focusing device can effectively improve the sensitivity of defect detection. The above research provides the basis for the design of steel wire rope damage detection systems and is of great significance to ensure the safe and efficient operation of mine hoisting equipment.

On the PMU Placement Optimization for the Detection of False Data Injection Attacks

The graph signal processing (GSP) approaches could facilitate the design of detectors for false data injection attacks (FDIAs) on smart grids. However, enhancing the performance of FDIA detection by optimizing the placement of phasor measurement units (PMUs) on smart grids remains an open problem. We formulate herein the detection of FDIAs as a binary hypothesis testing problem within the Grid-GSP framework and develop a subspace-based projection detection (SPD) algorithm, incorporating a quasi-optimal PMU placement strategy and two double thresholds. The proposed quasi-optimal PMU placement strategy enhances the performance of the SPD in FDIA detection. We further propose to enhance the SPD with the dynamic double threshold for high dynamic load profiles beyond a simple yet efficient static double threshold. Illustrative simulations based on the IEEE 118 bus test grid and the ERCOT dataset validate the superior performance of the proposed quasi-optimal PMU placement strategy along with the two double thresholds.

The value of using heterogeneous detector groups for the development of time-of-flight (TOF) positron emission tomography (PET) systems.

Objective. Much recent attention on positron emission tomography (PET) is the development of time-of-flight (TOF) systems with ever-improving coincidence time resolution (CTR). This is because, when all other factors remain the same, a better CTR leads to images of better statistics and effectively increases the sensitivity of the system. However, detector designs that aggressively improve the CTR often compromise the detection efficiency (DE) and offset the benefit gained. Under this circumstance, in developing a TOF PET system it may be beneficial to employ heterogeneous detector groups to balance the overall CTR and DE of the system. In this study, we examine the potential value of this system design strategy by considering two-dimensional systems that assume several representative ways of mixing two detector groups.Approach. The study is based on computer simulation and specifically considers medium time-resolution (MTR) detectors that have a 528 ps CTR and high time-resolution (HTR) detectors that have a 100 ps CTR and a DE that is 0.7 times that of the MTR detector. We examine contrast recovery, noise, and subjective quality of the resulting images under various ways of mixing the MTR and HTR detectors.Main results. With respect to the traditional configuration that adopts only the HTR detectors, symmetric heterogeneous configurations may offer comparable or better images while using considerably fewer HTRs. On the other hand, asymmetric heterogeneous configurations may allow the use of only a few HTRs for improving image quality locally.Significance. This study demonstrates the value of the proposed system-level design strategy of using heterogeneous detector groups for achieving high effective system sensitivity by factoring into the tradeoff between the CTR and DE of the detector.

Advanced detector and data pipeline design to fully utilize experiments at next-generation synchrotron sources

Advanced detector and data pipeline design to fully utilize experiments at next-generation synchrotron sources

Emission of coherent spin waves from a helimagnetic layer embedded within a ferromagnetic matrix

We have studied the Schlömann emission of exchange spin waves by a microwave driven helimagnetic layer containing integer and half-integer numbers of turns into surrounding semi-infinite ferromagnetic media. Analytical expressions of the emitted spin-wave’s amplitude and phase are obtained in closed form. For the case of a half-integer number of turns, we propose a method for applying the driving magnetic field so that the emission has an asymmetric (nonreciprocal) character, controlled by the polarization of the driving magnetic field. Our results can be used both in the design of polarization-sensitive magnonic detectors of microwaves and in using microwaves to characterize the microscopic configuration of non-collinear magnetic materials.

New detector design of STORNI neutron imaging facility at RA-6 research reactor

The paper describes an upgrade of the neutron imaging facility at the RA-6 research reactor in Argentina. The RA-6 reactor is mainly used for education and training. Still, it is also equipped with several research facilities such as a neutron boron capture therapy facility, neutron activation analysis facility and neutron imaging facility. In 2022, the detection system of the neutron imaging facility was upgraded with the use of an astronomical CMOS camera and a 3D-printed housing. The upgrade was focused on improvements to the optical components resulting in better image quality and spatial resolution.

Conceptual design of a sorption-based cryochain for the ETpathfinder

Next-generation gravitational wave detectors, including the Einstein Telescope [1][2], aim to achieve amplitude-spectral-density strain sensitivities on the order 10−24m/Hz[3]. In the low-frequency band such sensitivities can only be obtained when thermal noise, mainly stemming from the mirror coating, is reduced by employing cryogenic cooling techniques for the mirrors. The optical surface of the mirror should not vibrate with strain noise amplitude spectral densities above 10−20m/Hz for the cryogenic mirrors in the Einstein Telescope [3]. The ETpathfinder research facility [4][5], aims to facilitate the development and testing of critical new technologies required for the design and operation of future gravitational wave detectors. A key enabling technology for the design and operation of such advanced interferometers is the cryogenic system that cools the main optics to a temperature of approximately 10 K. Given the stringent requirements on vibrational noise for these optics, the cryogenic cooling under continuous operation should be essentially vibration free. Joule-Thomson cryocoolers using sorption compressors are known to generate an absolute minimum of vibrational noise during operation. We propose a modular cryochain design comprised of a system of sorption compressors and Joule-Thomson cold stages fitting the ETpathfinder project requirements. In this paper, we present the conceptual design of the cooler chain that is based on a parallel cascade arrangement of a 40 K neon stage, a 15 K hydrogen stage and a 8 K helium stage. The operating parameters of the sorption-based cooler chain are selected via a hybrid modeling workflow, aiming to optimize performance and other design considerations within an envelope of acceptable design parameters.