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Calibration of 22 gamma camera units was performed at 15 hospitals in southern and western Sweden to estimate 137Cs contamination in humans in a supine static geometry, with a new developed calibration protocol and phantom. The minimum detectable activities (MDAs) and the estimated committed effective doses (CEDs) were calculated for each calibration. Generic calibration factors were calculated for five predetermined groups based on the detector type and manufacturer. Group 1 and 2 included NaI-based gamma cameras from General Electrics (GEs) with a crystal thickness of 5/8′′ and 3/8′′ respectively. Group 3 and 4 included NaI-based gamma cameras from Siemens Healthineers with a crystal thickness of 3/8′′, with a similar energy window as the GE NaI-based cameras and a dual window respectively. Group 5 included semiconductor-based gamma cameras from GE with a CdZnTe (CZT) detector. The generic calibration factors were 60.0 cps kBq−1, 52.3 cps kBq−1, 50.3 cps kBq−1, 53.2 cps kBq−1 and 48.4 cps kBq−1 for group 1, 2, 3, 4, and 5 respectively. The MDAs ranged between 169 and 1130 Bq for all groups, with measurement times of 1–10 min, corresponding to a CED of 4.77–77.6 μ Sv. A dead time analysis was performed for group 1 and suggested a dead time of 3.17 μ s for 137Cs measurements. The dead time analysis showed that a maximum count rate of 232 kcps could be measured in the calibration geometry, corresponding to a CED of 108–263 mSv. It has been shown that semiconductor-based gamma cameras with CZT detectors are feasible for estimating 137Cs contamination. The generic calibration factors derived in this study can be used for gamma cameras of the same models in other hospitals, for measurements in the same measurement geometry. This will increase the measurement capability for estimating internal 137Cs contamination in the recovery phase following radiological or nuclear events. [ABSTRACT FROM AUTHOR]

The Sea-Bird 63 dissolved oxygen optode sensors used on various oceanographic platforms are known to drift over time. Corrections for drift are necessary for accurate dissolved oxygen measurements on the time scale of months to years. Here, drift on 14 Sea-Bird 63 dissolved oxygen optode sensors deployed on Spray underwater gliders over 5 years is described. The gliders with oxygen sensors were deployed regularly for 100-day missions as part of the California Underwater Glider Network (CUGN). A laboratory two-point calibration was performed on the oxygen sensor before and after glider deployment. Sensor drift during 100-day deployments was larger than during 100-day storage periods. Sensor behavior is modeled with a gain that asymptotically approaches 1.090 ± 0.005 with an e-folding time scale of 3.70 ± 0.361 years. At zero oxygen concentration, the sensor consistently reads around 3 μmol kg−1; a negative offset term is used in addition to the gain to correct the sensor oxygen. The correction procedure removes the error due to long time drift, one of the major sources of error, with an uncertainty of 0.5% (0.9% including outliers) or 0.5 μmol kg−1 depending on concentration, which improves the accuracy of the Sea-Bird 63 although uncertainty from other sources of error including the initial factory calibration and the sensor response time remain. Suggested procedures for implementing a two-point calibration procedure in the laboratory are discussed. Calibrations must be considered starting 6 months after initial factory calibration to keep error from sensor time drift under 1%. Significance Statement: Dissolved oxygen measurements are widely used in oceanography. The optode sensors used to measure dissolved oxygen are known to drift over time. Here, the characteristics of drift for the oxygen optode sensor from Sea-Bird Scientific are described using a two-point calibration at zero and full saturation. The calibration procedure can be applied to oxygen optode sensors deployed on a variety of platforms when it is impractical to complete a multipoint calibration. [ABSTRACT FROM AUTHOR]

Alpha particle detection performances of a Hamamatsu R1828-01 model and a RCA 6342A model photomultiplier tubes (PMT) were tested. For the sensitivity of the PMTs to alpha particles, an Eljen AJ-440 model ZnS(Ag) scintillator material in sheet form was used in front of their windows. To test their performances, the alpha peaks of an 241Am source and the energy resolution values of the detectors that composed of these PMTs were compared. It has been showed that R1828-01 model PMT utilized for fast timing measurements in radiation detection could be used in alpha particle detection efficiently. This work revealed its another advantageous feature in addition to existing specifications. [ABSTRACT FROM AUTHOR]

A heavy-ion collision facility called the cooler storage ring (CSR) external-target experiment (CEE) is scheduled in Lanzhou, China. The time measurement of the charged particles at the forward angle will be conducted by the external time-of-flight (eTOF) subsystem, which is built with multigap resistive plate chambers (MRPC). This work describes the tasks, performance criteria, detector layout, and prototype test results while outlining the technical design and development status of the CEE-eTOF wall. The effectiveness of the wall design has been validated using a FairRoot-based simulation, which is an essential part of the verification. With a 3.2 × 1.6 m 2 coverage, a 60 ps overall time resolution, and a 2.6 m distance from the collision point, the eTOF wall enables the particle identification, system triggering, and event selection in cooperation with other related detectors. A novel structure called sealed MRPC will be applied to the subsystem. The design considerations of this type, prototype test, and results are also described in this paper. [ABSTRACT FROM AUTHOR]

New transdermal biosensors measure analytes that diffuse from the bloodstream through the skin, making it important to reduce the system response time and understand measurement output. While highly customized models have been created for specific sensors, a generalized model for transdermal sensor systems is lacking. Here, a simple one-dimensional diffusion model was used to characterize the measurement system and classify biosensors as either flux types or concentration types. Results showed that flux-type sensors have significantly faster response times than concentration sensors. Furthermore, flux sensors do not measure concentration, but rather have an output measurement that is proportional to skin permeability. These findings should lead to an improved understanding of transdermal measurements and their relation to blood analyte concentration. In the realm of alcohol research, where the majority of commercially available sensors are flux types, our work advocates toward moving away from transdermal alcohol concentration as a metric, and instead suggests embracing transdermal alcohol flux as a more suitable alternative. [ABSTRACT FROM AUTHOR]

One of the key properties of single-photon detectors is their recovery time, i.e., the time required for the detector to recover its nominal efficiency. In the case of superconducting nanowire single-photon detectors (SNSPDs), which can feature extremely short recovery times in free-running mode, a precise characterization of this recovery time and its time dynamics is essential for many quantum optics or quantum communication experiments. We introduce a fast and simple method to characterize precisely the recovery time of SNSPDs. It provides full information about the recovery of the efficiency in time for a single or several consecutive detections. We also show how the method can be used to gain insight into the behavior of the bias current inside the nanowire after a detection, which allows predicting the behavior of the detector and its efficiency in any practical experiment using these detectors. [ABSTRACT FROM AUTHOR]

Particle identification is an important feature of the future SPD (Spin Physics Detector) experiment at the NICA (Nuclotron-based Ion Collider fAcility) collider. In particular, the identification of particles with momenta up to a few GeV / c (with c the speed of light) by their time-of-flight facilitates the reconstruction of events of interest. The high time resolution of modern TOF (Time-Of-Flight) detectors demands the need to obtain the event collision time, t 0 , with comparable accuracy. While the determination of the collision time is feasible through the use of TOF signals supplemented by track reconstruction, it proves to be computationally expensive. In the presented study, a dedicated Genetic Algorithm is developed as a fast and accurate method to determine the proton–proton collision time by the measurements of the TOF detector at the SPD experiment. By using this reliable method for the t 0 determination we compare different approaches for the particle identification procedure based on TOF signals. [ABSTRACT FROM AUTHOR]

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The goal of the paper is the design of soft sensors for single input single output (SISO) nonlinear processes. This goal is of essential importance for process monitoring, fault detection and fault isolation. The observer-based technique, being a fruitful direction in soft sensor design, is followed to develop soft sensors for nonlinear processes with known dynamics and unknown physical parameters. A new and general approach, based on the identified I/O linear approximant system descriptions, around prespecified operating points, and a bank of switching linear observers, will be developed. The system property of the I/O reconstructability of the state space linear approximant of a nonlinear model is presented. The design of each observer is based on the I/O measurements and structural characteristics of the nonlinear process. Observer-oriented target areas are introduced, and the respective dense web principle is formulated. The design is completed by the design of a data-driven rule-based system, providing stepwise switching among the observers of the bank. The number of observers of the bank is equal to the number of the linear approximants of the nonlinear process model and is equal to the number of the respective target operating areas. The target operating areas are required to satisfy the dense web principle. The information provided by the soft sensor is the estimation of the non-measured variables of the process. The information used by the soft sensor is the identified I/O approximants of the process as well as the real time values of the measurement variables. The efficiency of the design scheme is illustrated through symbolic and numerical simulation results for a chemostat. The nonlinear model of the chemostat is initially approximated by a set of ten linear approximants. After, the I/O approximants are identified, the respective observers are designed and the target operating areas are determined, where several cases of the satisfaction of the dense web principle are investigated. The soft sensor is composed in terms of the designed observers. Simulation results illustrate the satisfactory performance of the designed soft sensor. [ABSTRACT FROM AUTHOR]

Traditional direction-finding systems are based on processing the outputs of multiple spatially separated antennas. The impinging signal Angle-of-Arrival (AOA) is estimated using the relative phase and amplitude of the multiple outputs that are sampled simultaneously. Here, we explore the potential of a single moving antenna to provide useful direction finding of a single transmitter. If the transmitted signal frequency is steady enough during the collection of data, a single antenna can be moved while tracking the phase changes to provide an Angle-of-Arrival measurement. The advantages of a single-antenna sensor include the sensor size, the lack of a need for multiple-receiver synchronization in time and frequency, the lack of mutual antenna coupling, and the cost of the system. However, a single-antenna sensor requires an accurate knowledge of its position during the data collection and it is challenged by transmitter phase instability, signal modulation, and transmitter movement during the measurement integration time. We analyze the performance of the proposed sensor, support the analysis with simulations and finally, present measurements performed by hardware configured to check the validity of the proposed single-antenna sensor. [ABSTRACT FROM AUTHOR]

The assessment of movement reaction time (RT) as a sideline assessment is a valuable biomarker for mild TBI or concussion. However, such assessments require controlled laboratory environments, which may not be feasible for sideline testing during a game. Body-worn wearable devices are advantageous as being cost-effective, easy to don and use, wirelessly transmit data, and ensure unhindered movement performance. This study aimed to develop a Drop-stick Test System (DTS) with a wireless inertial sensor and confirm its reliability for different standing conditions (Foam versus No Foam) and task types (Single versus Dual), and postures (Standing versus sitting). Fourteen healthy young participants (seven females, seven males; age 24.7 ± 2.6 years) participated in this study. The participants were asked to catch a falling stick attached to the sensor during a drop test. Reaction Times (RTs) were calculated from data for each trial from DTS and laboratory camera system (gold standard). Intraclass correlation coefficients (ICC 3,k) were computed to determine inter-instrument reliability. The RT measurements from participants using the camera system and sensor-based DTS showed moderate to good inter-instrument reliability with an overall ICC of 0.82 (95% CI 0.78–0.85). Bland–Altman plots and 95% levels of agreement revealed a bias where the DTS underestimated RT by approximately 50 ms. [ABSTRACT FROM AUTHOR]

This article presents the design and test results of a waveform sampling application-specific integrated circuit (ASIC) based on the switched capacitor array (SCA). It integrates eight differential-input channels, and each channel consists of a 256-cell capacitor array, 256 12-bit Wilkinson analog-to-digital converters (ADCs), and a serial data readout. A sampling rate of up to 5 Gsps is achieved with a low-jitter delay-locked loop (DLL). Two shared coarse counters running at the rising and falling edges of the reference clock are used to extend the time measurement range. Several crosstalk reduction strategies were adopted in the circuit design, especially in the clock generation circuit and the digitization circuit. The ASIC has been fabricated in 180-nm CMOS process. The test results show that the random noise is approximately 0.7-mV rms after the fixed-pattern noise correction and that the precision of waveform timing is better than 7-ps rms with the sampling interval correction. [ABSTRACT FROM AUTHOR]

High-throughput on-line Raman detection has become commonplace in pharmaceutical and PAT. This has increased the demand for efficient, parallel spectral detection. In this work, a method of adjusting the optical structure parameters through multi-field theory is proposed to realize the detector accepting two spectral information from the light source at the same time. By combining two Raman probes and two customized Y-fibers, Raman spectra of two samples at the same laser power can be acquired simultaneously online. Compared with the multi-channel Raman spectroscopy detection system based on microscope device and multiple Raman spectroscopy coupling system, the measurement time and cost are greatly reduced. Thus, dual-channel Raman spectroscopy detection devices provide a cost and time-saving method for modern high-throughput on-line Raman detection. [ABSTRACT FROM AUTHOR]

Positron annihilation age–momentum correlation (AMOC) spectroscopy is not only a critical approach to investigate positronium formation and annihilation, but also a powerful technique for materials science to characterize the chemical environment of pores. However, due to the long measurement time (several days to collect 10 million counts for one sample, at a low coincidence counting rate of approximately 20–40 cps) of a conventional non-beam-based AMOC spectrometer, AMOC technique has been rarely applied. In this work, based on the geometrical simulations of detectors using Geant4 program, we developed a new semi-digital AMOC spectrometer with two start detectors. After systematic optimizations of geometrical configurations of detectors, timebase of digital oscilloscope, and the energy windows of start and stop detectors, this instrument achieved the highest coincidence counting rate for a non-beam-based AMOC spectrometer (∼ 180 cps for a narrow stop energy window of 469–589 keV and the shaping time of HPGe detector at T HPGe shaping = 6 μ s , and ∼ 500 cps for a wide stop energy window of 104–589 keV and T HPGe shaping = 2 μ s). The drastic rise of coincidence counting rate will broaden the applications of AMOC spectrometers in positronium physics and materials characterization in future. • Simulations and experiments of the geometrical optimization of AMOC system were performed. • A method was proposed to merge PAL spectra with different channel widths. • Various basetime configurations that affect the counting rate of AMOC system were discussed. • The effects of energy windows of start and stop detectors on the counting rate of AMOC system were studied. • The highest coincidence counting rate was achieved for a non-beam-based AMOC spectrometer. [ABSTRACT FROM AUTHOR]

We report on the development of a custom particle detection system that aims to improve the detection capabilities of the ROSPHERE array. The detector is designed specifically for lifetime measurements using the in-beam Fast-timing method for nuclear states in nuclides produced in nuclear transfer reactions. An 80 x 3.6 mm disc of BC400 plastic scintillator was coupled to a sparse SiPM array readout connected to a dedicated Front End Electronics board. The detector was tested versus a conical LaBr 3 (Ce) coupled to a Hamamatsu PMT readout. The timing measurements resulted in a resolution of 896(5) ps. The detector design, characteristics, and performances are presented in this paper along with future improvements. [ABSTRACT FROM AUTHOR]

A novel Compton Scanner setup has been built, commissioned and operated at the Max-Planck-Institute for Physics in Munich to collect pulses from bulk events in high-purity germanium detectors for pulse shape studies. In this fully automated setup, the detector under test is irradiated from the top with 661.660 keV gammas, some of which Compton scatter inside the detector. The interaction points in the detector can be reconstructed when the scattered gammas are detected with a pixelated camera placed at the side of the detector. The wide range of accepted Compton angles results in shorter measurement times in comparison to similar setups where only perpendicularly scattered gammas are selected by slit collimators. In this paper, the construction of the Compton Scanner, its alignment and the procedure to reconstruct interaction points in the germanium detector are described in detail. The creation of a first pulse shape library for an n-type segmented point-contact germanium detector is described. The spatial reconstruction along the beam axis is validated by a comparison to measured surface pulses. A first comparison of Compton Scanner pulses to simulated pulses is presented to demonstrate the power of the Compton Scanner to test simulation inputs and models. [ABSTRACT FROM AUTHOR]

In this study, we propose tunable pH sensors based on the electric-double-layer transistor (EDLT) with time-dependent sensitivity characteristics. The EDLT is able to modulate the drain current by using the mobile ions inside the electrolytic gate dielectric. This property allows the implementation of a device with sensitivity characteristics that are simply adjusted according to the measurement time. An extended gate-type, ion-sensitive, field-effect transistor consisting of a chitosan/Ta2O5 hybrid dielectric EDLT transducer, and an SnO2 sensing membrane, were fabricated to evaluate the sensing behavior at different buffer pH levels. As a result, we were able to achieve tunable sensitivity by only adjusting the measurement time by using a single EDLT and without additional gate electrodes. In addition, to demonstrate the unique sensing behavior of the time-dependent tunable pH sensors based on organic–inorganic hybrid EDLT, comparative sensors consisting of a normal FET with a SiO2 gate dielectric were prepared. It was found that the proposed pH sensors exhibit repeatable and stable sensing operations with drain current deviations <1%. Therefore, pH sensors using a chitosan electrolytic EDLT are suitable for biosensor platforms, possessing tunable sensitivity and high-reliability characteristics. [ABSTRACT FROM AUTHOR]

An alpha particle detector was constituted by favour of an MPPC (Multi-Pixel Photon Counter) using a ZnS(Ag) sheet named "spinthariscope." It was coupled to front side of the MPPC's window. Since obtained 226Ra alpha spectrum by the MPPC was highly noisy, a timing measurement method (constant fraction discrimination) was implemented to overcome this unfavourableness. Obtained results showed that the used timing method was quite successful for acquiring the noise discriminated alpha spectrum and improving the alpha peak energy resolution. It was concluded from this proposed experimental technique that an MPPC could be used as an alpha detector via a spinthariscope and improved the alpha peak resolution using the mentioned timing measurement method. [ABSTRACT FROM AUTHOR]

The process e + e - → n n ¯ is studied in the experiment at the VEPP-2000 e + e - collider with the SND detector. The technique of the time measurements in the multichannel NaI(Tl) electromagnetic calorimeter is used to select n n ¯ events. The value of the measured cross section in the center-of-mass energy range from 1.894 to 2 GeV varies from 0.5 to 0.35 nb. The effective neutron timelike form factor is derived from the measured cross section and compared with the proton form factor. The ratio of the neutron electric and magnetic form factors is obtained from the analysis of the antineutron polar angle distribution and found to be consistent with unity. [ABSTRACT FROM AUTHOR]

Fast fluorescence lifetime (FL) determination is a major factor for studying dynamic processes. To achieve a required precision and accuracy a certain number of photon counts must be detected. FL methods based on single-photon counting have strongly limited count rates because of the detector's pile-up issue and are suffering from long measurement times in the order of tens of seconds. Here, we present an experimental and Monte Carlo simulation-based study of how this limitation can be overcome using array detectors based on single-photon avalanche diodes (SPADs). We investigated the maximum count rate per pixel to determine FL with a certain precision and accuracy before pile-up occurs. Based on that, we derived an analytical expression to calculate the total measurement time which is proportional to the FL and inversely proportional to the number of pixels. However, a higher number of pixels drastically increases data rate. This can be counteracted by lowering the time resolution. We found that even with a time resolution of four times the FL, an accuracy of 10% can be achieved. Taken all together, FLs between 10 ns and 3 ns can be determined with a 300-pixel SPAD array detector with a measurement time and data rate less than 1 µs and 700 Mbit/s, respectively. This shows the enormous potential of SPAD array detector for high-speed applications requiring continuous data read out. [ABSTRACT FROM AUTHOR]

Resistive Plate Chambers (RPC) detectors play a crucial role in triggering events containing muons in the central region of ATLAS. In view of the High Luminosity-LHC program, the existing RPC system, consisting of six independent cylindrical detector layers each providing a full space time localization of hits, is currently undergoing a significant upgrade. In the next few years, 306 triplets of new generation RPCs will be installed in the innermost region of the ATLAS Muon Barrel Spectrometer, increasing from 6 to 9 the number of tracking layers, doubling the trigger lever arm. This allows a substantial enhancement of the present trigger redundancy, increasing the coverage from 76% to approximately 96%. Fitting new chambers in the narrow space left in ATLAS inner barrel was a challenge, achieved by optimizing RPC materials and thickness, featuring a 1 mm gas gap (instead of 2 mm), and 1.4 mm resistive electrodes (instead of 1.8 mm) while reaching an high rate capability. To achieve such results, a 100 ps precise Time-to-Digital Converter (TDC) has been integrated in the front-end electronics ASIC. The expected time resolution of a single 1 mm RPC gas gap is approximately 300 ps, and the possibility of a stand-alone Time of Flight measurement will have a huge impact on ATLAS searches for massive long-lived particles. An overview and the present status of the ATLAS RPC Phase-II project will be presented. [ABSTRACT FROM AUTHOR]

We have operated the MEG II pixelated timing counter maintaining its overall timing resolution at high level for precise timing measurement of positrons. Since its construction in 2017, the detector's pixels have shown degradation with high-rate beam irradiation and components (plastic scintillators, SiPMs) aging over time. In 2024, using new 960 SiPMs, we produced and mounted new 80 pixels onto the detector with estimation of the performance improvement. [ABSTRACT FROM AUTHOR]

Gamma detectors consisting of lanthanum bromide (LaBr 3) scintillator and silicon photomultiplier (SiPM) have extensive applications in various scientific fields. Accurate gamma energy measurement depends on accurate calibration of these detectors. While some studies have attempted detector self-calibration based on the natural background of LaBr 3 , these methods are limited to specific LaBr 3 crystals and lack generality. To address this limitation, this paper proposes a self-calibration method that solely utilizes the natural radioactivity of 138La. By solving for the maximum similarity between the test background from measurement and the standard spectrum obtained from the Geant4 simulation, the detector is effectively calibrated. Furthermore, the application of a series of energy spectrum processing algorithms simplifies the solution complexity of the maximum similarity problem. Experimental results from four different crystals at varying temperatures demonstrate calibration errors of less than 0.8% at 662 keV, highlighting the method's broad applicability and accuracy. Besides, the influence of the background measurement time and the natural environmental background on the self-calibration method are discussed in detail, further illustrating the value of the application. [ABSTRACT FROM AUTHOR]

Within the ATTRACT FASTPIX project, a monolithic pixel sensor demonstrator chip has been developed in a modified 180 n m CMOS imaging process, targeting sub-nanosecond timing measurements for single ionizing particles. It features a small collection electrode design on a 25 micron thick epitaxial layer and contains 32 mini matrices of 68 hexagonal pixels each, with pixel pitches ranging from 8.66 to 20 micron. Four pixels are transmitting an analog output signal and 64 are transmitting binary hit information. Various design variations are explored, aiming at accelerating the charge collection and making the timing of the charge collection more uniform over the pixel area. Signal treatment of the analog waveforms, as well as reconstruction of time and charge information, is carried out off-chip. This contribution introduces the design of the sensor and readout system and presents the first performance results for 10 μ m and 20 μ m pixel pitch achieved in measurements with particle beams. [ABSTRACT FROM AUTHOR]

Range-based target localization combines the range measurements and appropriate algorithms [such as time of arrival (TOA)] to determine the real-time position of a moving target not only in a satellite-denied environment but also for high-precision applications in an open (i.e., satellite-available) environment. However, the measurements from sensors always suffer from uncertainties, such as noises, outliers, dropouts, and biases, which make measurements not reliable enough to directly utilize in positioning. This article is, therefore, concerned with two kinds of sensor correction problems: 1) attenuating the noises, removing the outliers, and completing the dropouts and 2) identifying the discredited sensors and forbidding them from use. Specifically, we model a range measurement time series from a ranging sensor as a nonstationary stochastic process and then use a local polynomial to regress the mean function in an online manner. The derivatives of the mean function are identified as the state variables in the state space, and the Kalman filter is used to estimate the states. We will show that: 1) the proposed method is simple yet effective in denoising the measurements and correcting the outliers/dropouts with very high accuracy and precision and 2) the defined and estimated states can clearly reflect the pattern of one type of nonspecific anomaly contained in the range time series, which enables the recognition of the dysfunctional sensors. [ABSTRACT FROM AUTHOR]

This paper presents results of the development of a small-sized free release monitor designed for the release of materials, various hand tools, equipment and instruments of nuclear enterprises and laboratories staff that weight up to 50 kg, from radiation control. To increase the registration sensitivity of controlled radionuclides, 12 scintillation units based on a 3" x 3" sized NaI (Tl) crystal were used as gamma-radiation detectors. Volume of the measuring chamber of the monitor amounted to 200 L, the chosen thickness of the low-background shielding was 50 mm. The values of the minimum detectable activity of the designed monitor for the point sources 123I, 131I, 99mTc, 18F were better than 100 Bq with measurement time not exceeding 60 seconds. [ABSTRACT FROM AUTHOR]

In this study, we propose effective monitoring equipment intended for monitoring the underground tunnel of illegal excavation (such as theft, jailbreak, and smuggling). It mainly detects the microseismic information produced by underground excavation in a short distance to detect the status of underground excavation. Based on the arrival time difference principle, the positioning mathematical models of the 5-1-1 layout method, 4-3 layout method, and 7-0-0 layout method are established, respectively. In the research process, the measurement and the placement error caused by the installation of a seismic detector are joined into the detectors. Simulation results show that the relative error and its average value are obtained when mining outside the monitoring area. The experiment results demonstrate that, first, the depth positioning error is positively affected by the number of seismic detectors. Then, the relative error of plane positioning can be reduced when the installation distance among detectors is increased. Finally, the main causes of location error include time measurement error, propagation velocity difference caused by terrain, and the performance of detector hardware. The array of a ground motion detector has a weak influence on it. These emerging trends will have profound impacts on application of an underground excavation system. [ABSTRACT FROM AUTHOR]

In picosecond timing detectors, the time over threshold (TOT) of detector signals is normally required to be measured to enhance the front-edge timing precision. The extremely narrow pulsewidth of these detector signals has posed challenges to the design of time-to-digital converters (TDCs) based on field programmable gate arrays (FPGAs) for TOT measurement. In this article, an FPGA-based tapped-delay-line (TDL)-type TDC is proposed to simultaneously measure the arrival time and TOT time of nuclear pulses. By propagating the hit signal along a single TDL, the proposed bubble-proof encoding scheme can extract the time information of two transitions of hit signal in one measurement. The minimum measurable TOT time is proved to be limited only by the electrical characteristics of low-voltage differential signaling (LVDS) receivers of FPGAs. Through the performance evaluation on the prototype with a Virtex Ultrascale + FPGA, where the minimum measurable TOT time can be as low as 370 ps, the rms precision reaches 3.0 ps for TOT time measurement. Given the pulsewidths ranging from 0.4 to 1.5 ns, the measured TOT time is highly consistent with the direct readout values from the oscilloscope in a wide temperature range. To apply the TDC into a microchannel plate photomultiplier tube (MCP-PMT)-based timing detector, the front-end electronics board with a dual-threshold TOT measurement is constructed. The joint beam test results show that the coincidence time resolution of two identical detector channels can be improved from 36.5 to 10.3 ps, which demonstrates the significance of TOT measurement to modern picosecond timing detectors. [ABSTRACT FROM AUTHOR]

An automatic target monitoring method based on photographs taken by a CMOS photo-camera has been developed for the MEG II detector. The technique could be adapted for other fixed-target experiments requiring good knowledge of their target position to avoid biases and systematic errors in measuring the trajectories of the outcoming particles. A CMOS-based, high resolution, high radiation tolerant, and high magnetic field resistant photo-camera was mounted inside the MEG II detector at the Paul Scherrer Institute (Switzerland). MEG II is used to search for lepton flavor violation in muon decays. The photogrammetric method's challenges, affecting measurements of low momentum particles' tracks, are the high magnetic field of the spectrometer, high radiation levels, tight space constraints, and the need to limit the material budget in the tracking volume. The camera is focused on the dot pattern drawn on the thin MEG II target, about 1 m away from the detector endcaps where the photo-camera is placed. Target movements and deformations are monitored by comparing images of the dots taken at various times during the measurement. The images are acquired with a Raspberry board and analyzed using custom software. Global alignment to the spectrometer is guaranteed by corner cubes placed on the target support. As a result, the target monitoring fulfills the needs of the experiment. [ABSTRACT FROM AUTHOR]

Assessing the position of the Bragg peak (BP) in hadron radiotherapy utilizing prompt-gamma imaging (PGI) presents many challenges in terms of detector physics. Gamma detectors with the capability of extracting the best energy, timing, and spatial information from each gamma interaction, as well as with high detection efficiency and count rate performance, are needed for this application. In this work we present the characterization of a pixel Čerenkov charge induction (CCI) thallium bromide (TlBr) detector in terms of energy and and electron drift time for its potential use in PGI. The CCI TlBr detector had dimensions of 4 × 4 × 5 mm3 and one of its electrodes was segmented in pixels with 1.7 mm pitch. A silicon photomultiplier (SiPM) was optically coupled to one of the faces of the TlBr slab to read out the Čerenkov light promptly emitted after the interaction of a gamma ray. The detector was operated stand-alone and the 1.275 prompt gammas from a 22Na radioactive source were used for the study. The electron drift time was obtained by combining the Čerenkov and charge induction signals and then used as a measure of the depth of interaction. The electron mobility in TlBr was estimated as ∼27 cm2 V−1 s−1. Energy resolutions between 3.4% and 4.0% at 1.275 MeV were obtained after depth-correction. These values improved to 3.0%–3.3% when events with drift times of 3–6 μs were selected. These results show the potential of pixel CCI TlBr detectors to resolve gamma interactions in the detector with mm-like accuracy in 3D and with excellent energy resolution. Previous studies with CCI TlBr devices have shown a timing resolution of <400 ps full width at half maximum when detecting 511 keV gamma rays, therefore, the timing accuracy is expected to improve with the increased energy of the gamma rays in PGI. While other important detector characteristics such as count rate capability remain to be studied, results from this work combined with other preliminary data show pixel CCI detectors can simultaneously provide excellent energy, timing, and spatial resolution performance and are a very promising option for PGI in hadron therapy. [ABSTRACT FROM AUTHOR]

The sensor bias estimation problem is crucial in autonomous driving systems for perception and target tracking. This work considers the bias estimation for two collocated synchronized sensors with slowly varying additive biases. The differences between the two sensors' observations are used to eliminate the target state. Consequently, the bias estimation is independent of the target-state estimation. The biases' observability condition is met when the two sensors' biases are Ornstein--Uhlenbeck stochastic processes with different time constants. The bias models, including the time constants and measurement noises, can be identified based on a sample autocorrelation or using the maximum-likelihood estimation technique. A maximumlikelihood measurement fusion technique is introduced for the biascompensated observations. Simulation results, for several scenarios with various bias model parameters, prove the consistency of the estimator. It is shown that the uncertainties of biases are significantly reduced by the estimation algorithm presented. The sensitivity of the proposed algorithm is also tested with mismatched filters as well as the estimated bias models. Finally, the benefits of bias estimation in measurement fusion are evaluated. [ABSTRACT FROM AUTHOR]

We present an experimental demonstration of additive point source localization (APSL), a sparse parametric imaging algorithm that reconstructs the 3-D positions and activities of multiple gamma-ray point sources. Using a handheld gamma-ray detector array and up to four 8 μ Ci 137Cs gamma-ray sources, we performed both source-search and source-separation experiments in an indoor laboratory environment. In the majority of the source-search measurements, APSL reconstructed the correct number of sources with position accuracies of ~20 cm and activity accuracies (unsigned) of ~20%, given measurement times of 2 to 3 min and distances of closest approach (to any source) of ~20 cm. In source-separation measurements where the detector could be moved freely about the environment, APSL was able to resolve two sources separated by 75 cm or more given only ~60 s of measurement time. In these source-separation measurements, APSL produced larger total activity errors of ~40%, but obtained source-separation distances accurate to within 15 cm. We also compare our APSL results against traditional maximum likelihood-expectation maximization (ML-EM) reconstructions and demonstrate improved image accuracy and interpretability using APSL over ML-EM. These results indicate that APSL is capable of accurately reconstructing gamma-ray source positions and activities using measurements from existing detector hardware. [ABSTRACT FROM AUTHOR]

The overall performance of complex industrial systems using control and optimization strategies is often hampered by the lack of available measurements of key quality variables. The development of a soft sensor is a solution that allows for the necessary process information to be made available. Due to the nonlinear characteristics of industrial processes, a new soft sensor development approach that incorporates infrequent, variable time delayed measurements is proposed. Based on the fast-sampled measurement and the nonlinear, first principles model, the frequent and delay-free key performance indicator (KPI) estimation is realized using the square-root unscented Kalman filter (SR-UKF). Then, a modified Kalman Filter (MKF) algorithm is proposed to deal with those infrequent, but accurate measurements, whose values are variably delayed in time. These two types of estimates are fused and optimized to give an optimal, reliable KPI estimate based on the distributed state fusion UKF filter algorithm. The performance and effectiveness of the proposed approach are demonstrated by an experimental application for alumina concentration monitoring in the aluminum electrolysis industry. [ABSTRACT FROM AUTHOR]

In view of its importance to applications in high-energy physics, nuclear security, and time-of-flight positron emission tomography (TOF-PET), the time resolution of 0.5% benzophenone-quenched EJ-232Q plastic scintillators of various lengths was studied using a fast waveform digitizer and fast photomultiplier tubes (PMTs). The scintillator sizes were 5 mm × 5 mm × 10, 25, 50, 75, or 100 mm. First, the timing measurements were performed by using a single PMT reading out one end. The degradation in time resolution with increasing scintillator length was studied. The irradiation geometry was also observed to have a nonnegligible impact on the time resolution due to the variation of depth-of-interaction (DOI) positions, especially for the scintillators with a high aspect ratio. Second, two PMTs were employed for a dual-sided readout. This readout together with the mean time method was demonstrated to be an effective approach to improve the timing performance since th. DOI-related effect was considerably mitigated. A time resolution of 79 ± 1 ps (full-width at half-maximum) has been achieved for the 5 × 5 × 10 mm3 scintillator. The 5 × 5 × 100 mm3 scintillator can still provide a time resolution as good as 172 ± 1 ps. The energy range used for each was between 340 and 450 keVee. In addition, the time information from individual PMTs in a dual-sided readout was able to show a time resolution almost identical to that determined with the mean-time-based technique after correcting for the DOI variation for the 100-mm-long scintillator. [ABSTRACT FROM AUTHOR]

A sensor uncertainty evaluation model that meets international GUM standards can provide a theoretical foundation for optimizing sensor structure parameters. In this study, a field type circle time-grating sensor was taken as the research object to build an effective uncertainty evaluation model. First, four main uncertainty sources of the field type circle time-grating sensor were found by deducing the mathematical expression of angle measurement and analyzing the sensor uncertainty sources. Second, the transitive relations between the main uncertainty sources and synthetic uncertainty were analyzed and deduced, respectively. Finally, an uncertainty evaluation model with all the main uncertainty sources was built based on modern uncertainty theory. A field type circle time-grating sensor with 72 poles was tested to verify the effectiveness of the proposed uncertainty evaluation model. The results indicated that the evaluation process in the experiment meets the international GUM standards. The peak-to-peak value of the measurement error for the whole week of the field type time grating in this study was 12.09′′. This value was in agreement with the 12.73′′ calculated from the formula of measurement uncertainty evaluation of the field type time grating, which can be used for the actual evaluation of field time grating measurement uncertainty. Moreover, the analysis results can provide a theoretical basis for the optimal design of the time grating sensor structure. [ABSTRACT FROM AUTHOR]

According to the new European Union Basic Safety Standards (EU-BSS), preparation of the National Radon Action Plan is obligatory for the Member States. One of the plan's aims is to carry out an indoor radon survey to identify radon-prone areas. In the radon surveys, track detector methods are used. At the University of Pannonia (Veszprém, Hungary), a new scanner-based detector evaluation system has been developed. For the application of the new system, the selection of appropriate parameters is necessary. In this study, selection of the applied track detectors and setting of the etching conditions have been carried out. Two different types of allyl diglycol carbonate (ADC or CR-39) track detectors were investigated, taking into account the detector's background and response during the exposure (determination of calibration factor). The Baryotrak's background track density (0–1.5 tracks mm−2) was lower than that of the 0.8–4 tracks mm−2. The response of the Tastrak was higher, but the deviation of the calibration factor was much higher (1.2–5.3 × 10−3 tracks mm−2/(Bq day m−3)) than in the case of the Baryotrak (1.4–2.8 × 10−3 tracks mm−2/(Bq day m−3)). After the systematic review of the etching system, a new method was developed. For the determination of the optimal track diameter, the argon fluoride (ArF) laser was applied to create tracks with diameters in the range of 10–100 μm. The optimum track size was in the range of 40–60 μm. On this basis, new etching conditions were determined: 6.25 M NaOH solution, a temperature of 90°C, and time period of 8 hours. [ABSTRACT FROM AUTHOR]

Optical sensors are useful tools for rapid and periodic assessment of plant nutritional status. However, the utility and potential of these sensors may be reduced if their readings change throughout the day. Therefore, this study aimed to assess the effects of time of day on measurements of the SPAD-502 chlorophyll meter and the GreenSeeker throughout the bean crop cycle. The treatments consisted of time of day for sensor measurements (8:00, 12:00, and 16:00 h) throughout six dates over the crop cycle. The results showed that measurements from the SPAD-502 and the GreenSeeker significantly changed according to time of day. The SPAD index at 16:00 h showed the lowest coefficient of variation (CV, 2.5%) and was on average, 3.05 ± 0.43, and 1.12 ± 0.25 SPAD units higher when compared to readings obtained at 8:00 and 12:00 h. Differently, the NDVI from the GreenSeeker showed the lowest CV (4.34%) at 8:00 h and was, on average, 0.06 ± 0.028 and 0.03 ± 0.01 units higher than measurements taken at 16:00 h and 12:00 h, respectively. Furthermore, the different times of sensor measurements present variations in air temperature and solar radiation, which directly influence the leaf water content and paraheliotropic movements. Thus, the indices from both sensors tend to show a high variability during different times of the day. Therefore, it is essential to create a consistent sampling protocol to reduce the variability of sensor measurements during the crop cycle. [ABSTRACT FROM AUTHOR]

In order to further improving noise performance and achieving higher spatial resolution for bio-magnetic sensing, there is a tendency to develop a multi-channel integrated system for micro magnetic sensors. In this study, we have developed a high resolution programmable oversampling MI sensor system, as a unit module for multi-channel integrated bio-sensor system, based on Pk-pk VD-type MI magnetometer. We have achieved a high field detection sensitivity with good linearity, and a noise level lower than 1 pT/Hz1/2, by utilizing the time-differential measurement in each MI element for suppressing the low frequency noise components and increasing the stability of sensor system. Meanwhile, the proposed MI sensor system can be easily enlarged into multi-channel system, and is more suitable for integration and mass production. Furthermore, we have successfully achieved the real time R peak and T wave measurements of magnetocardiography (MCG) via new MI sensor system, with a high real time signal-to-noise ratio (SNR) of about 20 dB. We have at the first time achieved the clear P wave measurements of MCG using MI sensor, in an unshielded environment. The real time MCG measurements via new MI sensor system at room temperature, in an unshielded environment, will contribute to the diagnosis of heart disease. [ABSTRACT FROM AUTHOR]

We present the development and discuss the performance of a compact scintillating fiber detector for the Mu3e experiment for accurate time measurements at very high particle rates. Mu3e is a new experiment under preparation at the Paul Scherrer Institut (PSI) to search for charged Lepton Flavor Violation in the neutrinoless muon decay μ + → e + e − e + with a projected sensitivity of 1 0 − 16 using the most intense continuous surface muon beam in the world. A very thin scintillating fiber detector (thickness < 0. 2 % of a radiation length X 0) with a time resolution of about 250 ps, efficiency around 97%, and spatial resolution of ∼ 100 μ m has been developed. The SciFi detector is read out with multi-channel silicon photomultiplier arrays at both ends to achieve the best timing performance. Different scintillating fiber types have been evaluated and various assembly procedures have been tested to achieve the best performance. [ABSTRACT FROM AUTHOR]

The study of heavy-ion reactions in the Fermi energy regime requires detection systems covering a high portion of the solid angle and using several identification techniques. Silicon detectors are widely used in this field. The so called E − T o F identification technique combines the energy and time of arrival of ions stopped in the detector to perform mass identification and calculate the velocity. However, when dealing with time measurements non-linear effects in detector and electronics responses have to be taken into account. We present an empirical method, as developed in the case of CHIMERA multi-detector, describing these non-linear effects and allowing for mass identification of ions stopped in the silicon detector by means of a semi-automatic procedure. Correlation between the non-linear effects affecting the ToF technique and the rise-time of the silicon detector signal will also be presented and discussed. [ABSTRACT FROM AUTHOR]

We have developed a prototype multi-gap Resistive Plate Chamber (RPC) for a time-of-flight (TOF) detector at the J-PARC π 20 beam line. It is a double stack RPC with five 0.26-mm gas gaps in each stack. Its readout strips are 25 mm wide and 940 mm long. We have also developed an amplifier board which can be used for TOF-RPCs in general and carried out a beam test to evaluate the performance of the RPC and this new board. Timing measurements and a time-walk correction using a time-over-threshold (TOT) method were found to work well without stretching signals. We obtained time resolutions of 60-70 ps when the test particle's position was determined using 5 mm × 10 mm trigger detectors and 65-80 ps without this position determination. [ABSTRACT FROM AUTHOR]

The use of precise time-of-flight (ToF) detectors for measurements of diffractive and electromagnetic processes in proton–proton collisions is discussed. The performance of background rejection exploiting the ToF measurements of the forward protons is derived. Influence of additional timing measurements delivered by the central detectors is presented and the possible gain is studied. [ABSTRACT FROM AUTHOR]

In this paper we report simulation results of a study aiming to optimize parameters of a detector that uses low-gain avalanche detectors (LGAD) for high-precision timing measurements. The detector is assumed to be composed of a 50 μ m LGAD sensor coupled to front-end readout electronics which is used to measure the time of arrival of minimum ionizing particles. The simulation includes modeling of signal fluctuations in the LGAD sensor, variations of the analog bandwidth and signal-to-noise ratio (SNR) of the front-end electronics, time bin quantization, and radiation damage of the LGAD sensors. Two approaches to measure the timestamp are considered: leading edge and constant fraction. Simulated LGAD pulses before irradiation, and after irradiation with neutron fluences of 5 × 1 0 14 n/cm 2 and 1 × 1 0 15 n/cm 2 , are studied. The time resolution for a 50 μ m LGADs was found to be 35 ps for front-end electronics bandwidths larger than 350 MHz and SNRs larger than 30. The time resolution at SNR of 30 for fluences of 5 × 1 0 14 n/cm 2 and 1 × 1 0 15 n/cm 2 were found to be 31 ps and 37 ps, respectively. [ABSTRACT FROM AUTHOR]

We investigated fluctuations of well-being by using a smartphone-based mobile experience sampling method (real-time and multiple time point measurements in the field using smartphones). Moreover, temperature, longitude, latitude, altitude, wind speed, rainfall, and further environment-based indicators were included as predictors either from smartphone sensors or from open-access Internet databases. Overall, a total of 213 participants reported on their well-being (over 14 days; three measurements per day; 8,000+ well-being judgments). We were able to replicate and refine past research about the dynamics of well-being fluctuations during the day (low in the morning, high in the evening) and over the course of a week (low just before the beginning of the week, highest near the end of the week). We also show what kind of benefits empirical researchers can gain for their research using smartphones and their built-in sensors by combining these measures with data from open-access databases. [ABSTRACT FROM AUTHOR]

Fast-timing measurements at the focal plane of a separator can suffer from poor timing resolution. This is due to the variations in time-of-flight (ToF) for photons travelling to a given detector, which arise from the changes in the implantation positions of the recoil nuclei emitting the γ rays of interest. In order to minimise these effects on timing measurements, a procedure is presented that improves fast-timing data by performing ToF corrections on an event-by-event basis. This method was used to correct data collected with an array of eight LaBr 3 detectors, which detected γ rays from spatially distributed 138Gd recoil-implants at the focal plane of the Recoil-Ion-Transport-Unit (RITU) spectrometer. The Generalised Centroid Difference (GCD) method was used to extract a lifetime from data in conjunction with a new procedure to calibrate the time walk. The lifetime of the first 2 + state in 138Gd, populated by the decay of the K π = 8 − isomeric state, was measured to be 229(24) ps using the ToF-corrected data, which is consistent within three standard deviations to the literature value. The results together with Monte-Carlo simulations show that the ToF correction procedure reduced the uncertainty in the measured lifetimes by 3 % in the case of the spatially distributed nuclei at the focal plane of RITU. However, ∼ 12 % has been estimated for a similar experiment when using a larger focal plane i.e. the Super-FRS at the FAIR facility. [ABSTRACT FROM AUTHOR]

Multi-function radar(MFR) is a system that uses various functions such as detection, tracking, and classification. To operate the functions in real-time, the detection stage in MFR usually uses radar signals for short measurement time. We can utilize several conventional detectors in the MFR system to detect low radar cross section maritime targets in the sea-clutter; however, the detectors, which have been developed to be effective for radar signals measured for a longer time, may be inappropriate for MFR. In this study, we proposed a modelling technique of sea-clutter short measurement time. We combined the modeled sea-clutter signal with the maritime-target signal, which was obtained by the numerical analysis method. Using this combined model, we exploited four independent detectors and analyzed the detection performances. [ABSTRACT FROM AUTHOR]