Counting Interval Research Articles

A novel GM-APD array-based heterodyne imaging detection system supports large array multi-pixel parallel target motion state image detection

Existing laser active imaging detection methods are limited by the detection mechanism, which can only capture the intensity image and distance image of the target, and lack practical detection solutions for acquiring images of the target motion state characteristics (non-macroscopic centroid motion, such as rotation, rolling, and other motion characteristics around the centroid). In this paper, a detection method using Geiger mode avalanche photodiode (GM-APD) array detector for heterodyne imaging to obtain images of the target motion state is proposed. An innovative method based on photon counting time interval calculation (PCTIC) is proposed to obtain the Doppler frequency shift of the target echo for each GM-APD pixel, which effectively eliminates useless data unrelated to the signal. With limited data storage and processing speed, the heterodyne imaging performance has been effectively improved to achieve high-precision heterodyne imaging detection of very weak target echoes and to support heterodyne imaging detection of large arrays with more image pixels in parallel. Experiments show that the method can achieve video-level detection at an imaging resolution of 32×32, and with a paucity of echo photons (detection probability of echo is 0.0032), a millimetre-level velocimetry measurement error can be achieved by accumulating only 6 echo photons per image element. The system also shows good resistance to turbulence interference, with target motion state characteristics detected based on velocity images remaining virtually unaffected under turbulence conditions caused by strong flames. This advancement is crucial for target detection in complex working environments such as smart manufacturing and autonomous driving.

Automatic tracking of the energy spectrum areas of Po-218 and Po-214 at various temperatures

Radon and its decay products emit internal radiation in the respiratory system upon inhalation, which is a significant contributor to the development of lung cancer in humans. Accurate measurement of radon concentration is undoubtedly very important. Among the commonly used radon measurement methods, the electrostatic collection method stands out. This method involves counting the energy spectrum peaks of alpha particles, generated by the decay of radon daughters Po-218 and Po-214, which are collected on the surface of a semiconductor detector to determine radon concentration. According to experimental findings, measurements at different ambient temperatures cause Po-218 and Po-214 to peak drift. This drift adversely affects the accuracy of radon measurement using traditional methods. This study focuses on the characteristics of α-energy spectra from Po-218 and Po-214. It calculates the peak heights for all α-energy spectra and identifies the two peaks with the highest heights. Subsequently, an algorithm is developed to automatically track the peak positions of Po-218 and Po-214, accurately locating their counting intervals. The results demonstrate that the algorithm successfully achieves the desired outcomes through experiments conducted at different temperatures and measurement durations, thus validating its effectiveness. This method holds significant practical value in ensuring the accuracy of radon measurement.

ОЦЕНКА КАЧЕСТВА ДОЗИРОВАНИЯ ПРИМЕСНОГО КОМПОНЕНТА ЛЕНТОЧНЫМ ПИТАТЕЛЕМ

The necessity of separate supply of grain mixture components to the experimental trier in the study of the process of separating long impurities from wheat was established. It is proposed to use distribution boxes without a bottom with dimensions of 0.6×0.06×0.07 m and a screeder with adjustable gate reach to ensure uniform distribution of the impurity component. The structure of the total error in the dosing of the impurity component during the interval control of its flow has been established. The errors in counting time intervals and the reaction of the operator with measuring containers to the sound signal have the greatest weight. Relationships between the dosing quality indicators: the standard deviation (σ) and the coefficient of variation (ν) with the time interval for monitoring samples leaving the belt feeder with an impurity mass in the distribution box of 0.360 kg were established, while with a decrease in the time interval for monitoring samples (toot) ν increased . With a change in t from 25 to 5 s, ν of the sampled impurities increased by 5.25 times. Isolation of the two most significant errors by summing the masses of the impurity over repetitions eliminates the error of discrete dosing - the difference from equivalent distributed masses is 0.67 - 2.33%, which is quite acceptable for the continuous dosing of the impurity under study. with the mass of impurities in the distribution box mp = 0.725 kg. With an increase in mp by 2 times, the value of the coefficient of variation for the time interval for sampling samples tot = 5 s decreased by 1.94 times.

Reducing loss of significance in the computation of Earth-based two-way Doppler observables for small body missions

Two-way Doppler measurement is a typical Earth-based radiometric technique for interplanetary spacecraft navigation and gravity science investigation. The most widely used model for the computation of two-way Doppler observables is Moyer’s differenced-range Doppler (DRD) formula, which is based on a Schwarzschild approximation of the Solar-System space-time. However, the computation of range difference in DRD formula is sensitive to round-off errors due to approximate numbers defined by the norm IEEE754 in all PCs. This paper presented two updated models and their corresponding detailed instructions for the computation of the two-way Doppler observables so as to impair the effects of this type of numerical error. These two models were validated by two case studies related to the Rosetta mission—asteroid Lutetia flyby and comet 67P/Churyumov-Gerasimenko orbiting case. In these two cases, the numerical noise from the updated models can be reduced by two orders-of-magnitude in the computed two-way Doppler observables. The results showed an accuracy from better than 6 × 10−3 mm s−1 at 1 s counting time interval to better than 3 × 10−5 mm s−1 at 60 s counting time interval.

Gamma peak search and peak fitting algorithm for a low-resolution detector with applications in gamma spectroscopy

A Savitzky–Golay filtering for smoothing and peak search written in Python is presented in this paper alongside its applications in the list-mode digital data acquisition dual gamma–gamma coincidence bismuth germanate (BGO) detector. The study has demonstrated that the software provides a reliable and effective way to quantify trace amounts of 22Na and 7Be in aerosol samples collected at Resolute Bay, Canada with a critical limit of 3 mBq and 5 Bq respectively for a 20 h counting interval, which are believed to be the inherent limitations of the dual-BGO system.

Protective effect of vitamin D against hyperoxia-induced bronchopulmonary dysplasia in newborn mice

To investigate the protective effect of vitamin D (VD) against hyperoxia-induced bronchopulmonary dysplasia (BPD) in newborn mice and explore the mechanism. Thirty-six newborn mice were randomly divided into air + VD group, air + saline group, hyperoxia + VD group, and hyperoxia + saline group. In all the groups, saline or VD was administered on a daily basis via intramuscular injection. After 3 weeks of treatment, the mice were weighed and cardiac blood was collected for measurement of serum VD level using ELISA, and histological examination of the lungs was performed. Radial alveolar counting (RAC) and alveolar secondary interval volume density were measured using image analysis software. The expression levels of vascular endothelial cell growth factor (VEGF) and VEGF receptor 2 (VEGFR2) in the lung tissues were detected using Western blotting. The weight gain rate of the mice and the weight of the lungs were significantly higher in air + saline group and air + VD group than in the hyperoxia + saline group. The RAC was significantly lower in hyperoxic+saline group than that in hyperoxia+VD group (P < 0.001), and was significantly higher in hyperoxic+VD (125 times) than in hyperoxia + VD (1250 times) group (P < 0.01). The alveolar secondary protrusion count was significantly higher in hyperoxic+VD (1250 times) group than in hyperoxic+saline group (P < 0.001), and was significantly higher in hyperoxia+VD (125 times) group than in hyperoxia + VD (1250 times) group (P < 0.01). Compared with that in air + saline group, VEGFR2 expression was significantly lowered in hyperoxia+saline group (P < 0.05) and in air+VD group (P < 0.05); VEGFR2 expression was significantly higher in hyperoxia+VD (1250 times) group than in hyperoxia+saline group (P < 0.001) and hyperoxia+VD (125 times) group (P < 0.001); VEGFR2 expression was significantly higher in hyperoxia+VD (125 times) group than in hyperoxia+ saline group (P < 0.05). In newborn mice with BPD, VD supplement can increase the weight of the lungs and promote lung maturation, and a higher concentration of VD can better protect the lungs and promote the growth of pulmonary blood vessels.

Difference Distributions Applicable to Certain Health Physics Measurements.

This paper discusses calculational methods for the determination of the difference distributions associated with certain health physics measurements. These measurements include the check-source response counts relative to an initial reference count, the Albatross (i.e., HPI model 2080B) neutron tube counts relative to the gamma tube counts, and those that involve the use of the automatic background subtraction feature of portable health physics instrumentation. Examples are provided that illustrate the methods for a few specific measurements. For the comparison of a daily source count to its previously determined reference value, minimum counts for various scenarios were presented in order to reliably meet required tolerance limits of ±10% and ±20%. In either case, it was found beneficial that the initial reference readings be established using a counting interval of longer length than the daily interval. For the comparison of Albatross neutron counts to the gamma counts, it was seen that the relative error in the difference distribution was still related to that of the parent distribution. It was seen, therefore, that an effective way of reducing the gamma influence on the Albatross was to increase the counting interval used, hence yielding a significantly larger mean count per interval. For the automatic background subtraction feature, it was noted that net count values near 0 counts would almost always have the negative values of the difference distribution truncated to 0 counts by commercially available off-the-shelf instrumentation, whereas significant net count values would be displayed correctly but with a larger associated variance than the gross count itself. This paper therefore also provides a technical basis for the necessary source strength of a check source in order to meet daily limits, the gamma field limitations of the HPI 2080B Albatross, as well as the consequences of automatic background subtraction.

An Alternative Approach to Estimating Instrument Decision Thresholds for Clearance of Personal Property From Accelerator Facilities.

Personal property exposed to particle beams and stray radiation at high-energy particle accelerators may contain induced volumetric radioactivity. At both the Brookhaven National Laboratory's (BNL) Collider-Accelerator and National Synchrotron Light Source II Facilities this radioactivity contains both gamma-emitting and beta-emitting radionuclides. The US Department of Energy (US DOE) recently published Technical Standard 6004-2016. This standard provides radionuclide-specific volumetric screening levels (Bq g) below which accelerator materials are eligible for clearance and release from radiological control. The standard also establishes several approaches for decision-making relative to the clearance process implemented, one of which is the "Indistinguishable from Background" (IFB) approach. BNL implements the IFB approach for survey of potentially activated accelerator materials. Radiological control technicians perform on-contact measurements using portable scintillators that are sensitive to gamma and x-ray radiation. Instrument decision thresholds are usually estimated by measuring total background counts over a pre-determined counting interval using an integrating count-rate instrument and then applying an appropriate confidence level factor. Measurement results obtained in a low background area are then directly compared to these detection thresholds. This paper presents an alternative statistical approach using logistic regression for estimating instrument decision thresholds for small-mass items using the IFB method and compares them to established release criteria. On-contact Micro-R meter measurements are correlated with analytical data obtained for activated materials weighing 0.3 kg to 3 kg. Analytical sample results show that Co and Na accounted for more than 90% of total sample radioactivity. Co and Na emit high-energy gamma rays and are both group one radionuclides as defined in DOE-6004-2016. For this size material the results show that the probability of detecting residual volumetric radioactivity at the Group One screening level concentration of 0.11 Bq g under normal field conditions is about 68%. This increases to 95% at 0.16 Bq g. The 95% confidence interval is 0.09 Bq g to 0.23 Bq g. Grouping low-mass items during the survey process could mitigate this concern if all items are expected to have similar activity concentrations.

Fruit and seeds biometry and germination of Psidium cauliflorum Landrum & Sobral

The biometric characterization of fruits and seeds, obtaining optimum temperatures and photoperiods for germi­nation and the definition of numbers and counting intervals in the germination tests of Psidium cauliflorum were the objectives of this work. Fruits were obtained from four matrices located in the Environmental Protection Area of Lago de Pedra do Cavalo, in Sao Goncalo dos Campos-BA. The following temperatures were tested: 25 °C; 30 °C; and 25-30 °C, in addition to three light conditions: absence of light; 8 h photoperiod; and 12 h photoperiod. One kilogram of fruit contains about 260 fruits and 1.344 seeds. Germination performance was higher at the alternating temperatures of 25-30 °C, in the presence of light (8 h photoperiod). The germination test lasted 77 days, with the first count at 21 days and subsequent counts at 15 day-intervals.

Scanning DMA data analysis II. Integrated DMA-CPC instrument response and data inversion

Analysis of scanning electrical mobility spectrometer (SEMS) or SMPS data requires coupling the scanning differential mobility analyzer (DMA) transfer function with the response functions for the instrument plumbing and the detector. In the limit of plug flow (uniform velocity) within the DMA, the scanning DMA transfer function has the same form as that for constant voltage. Most SEMS/SMPS data analysis uses this model, though previous studies have shown that boundary layers distort the transfer function during scanning DMA measurements. Part I determined the instantaneous transfer function during scanning of the TSI Model 3081 A long column DMA by modeling the flows, fields, and particle trajectories within the actual DMA geometry. This study (Part II) combines that transfer function with empirical data on the efficiencies and delay time distributions of the plumbing and detector of the SEMS/SMPS to determine the instantaneous rate at which particles are counted, and integrates the count rate over the finite counting time interval to obtain the integrated SEMS/SMPS response function. Simulations using this geometrical model are compared with those obtained using traditional, idealized DMA models for scan rates ranging from slow (240 s) to very fast (10 s), and with measurements of monodisperse calibration aerosols. Data inversion studies show that both increasing and decreasing voltage scans can be used to determine the particle size distribution, even with fast scans.

Towards near real-time SEMS size distribution measurements under up-scan operation

Near real-time particle size distribution measurements with a scanning electrical mobility spectrometer (SEMS) requires a fast scan DMA operation. The classification characteristics of the DMA when operated with an up-scan voltage can be established from calculations of particle arrival-times at the sample port of the DMA. This approach, referred to as the arrival-time transfer function (ATF) calculation approach, has been shown to accurately calculate DMA mobility transfer functions under up-scan operation for a range of scan times. Fast SEMS operation, however, are further complicated by downstream effects of particle smearing, plumbing delays (offset time) and counting time interval of the particle counter. These effects have thus far been quantified empirically. In this paper, a theoretical framework is proposed to minimize empirical corrections. The effects of particle smearing, plumbing delays (offset time) and counting time interval are incorporated in determining SEMS transfer functions, which are then used to predict the signal response to a known upstream size distribution under different operating conditions. The predicted signals are then validated with experimental data with scan times as fast 5 s. Using the calculated SEMS transfer functions and a regularization-based inversion algorithm, we are able to accurately invert SEMS signals from a scan as fast as 5 s. Our proposed SEMS transfer function calculation approach, thus, suggests that near real-time, accurate size distributions may be possible with SEMS measurements.

GEANT4 investigation of 40K and 222Rn interference effects on actinide detection sensitivities of CEMRC BEGe lung detectors

Internal dosimetry measurements of trans-uranic (TRU) radionuclides within the human body can be accomplished by γ-ray spectroscopy using high-purity germanium detectors. While measurements are typically conducted inside shielded chambers in order to minimize the background detector signal, the presence of radioactive 40K within the body cannot be removed, which produces a high-energy γ ray at 1461 keV. The 40K, in addition to airborne 222Rn, contributes to the radiation field within the chamber that increases to the minimum detectable activity that can be achieved in practice.The objective of the present work is to estimate the contributions from 40K internal to the human body and airborne 222Rn to the background signal in a lung counter germanium detector array using GEANT4 simulations, with a focus on TRU isotope energy region (17–59 keV). The investigations consisted of three main simulations:1.Simulating the γ-ray flux at the geometric center of the CEMRC counting chamber arising from a 25 nCi source of 40K from (a) a point source, and (b) a source distributed throughout a BOMAB phantom.2.Simulating the response of the CEMRC BEGe detectors arising from a 25 nCi source of 40K from (a) a point source, and (b) a source distributed throughout a BOMAB phantom.3.Simulating the response of the CEMRC BEGe detectors to the environmental background in the counting chamber, consisting of airborne 222Rn (0–4 pCi/L) and 40K (0–160 nCi) internal to the human body.The results are used to investigate the 40K background contribution to a routine spectrum recorded by the lung detectors at the CEMRC Internal Dosimetry laboratory over a typical half hour counting interval used in the dosimetry of radiological workers. The minimum detectable activity was calculated for various 222Rn and 40K activities and compared to experimentally determined values. The contribution of cosmic rays was not included in this investigation.

Feasibility of beta-particle radioguided surgery for a variety of “nuclear medicine” radionuclides

PurposeBeta-particle radioguided tumor resection may potentially overcome the limitations of conventional gamma-ray guided surgery by eliminating, or at least minimizing, the confounding effect of counts contributed by activity in adjacent normal tissues. The current study evaluates the clinical feasibility of this approach for a variety of radionuclides. Nowadays, the only β- radioisotope suited to radioguided surgery is 90Y. Here, we study the β- probe prototype capability to different radionuclides chosen among those used in nuclear medicine. MethodsThe counting efficiency of our probe prototype was evaluated for sources of electrons and photons of different energies. Such measurements were used to benchmark the Monte Carlo (MC) simulation of the probe behavior, especially the parameters related to the simulation of the optical photon propagation in the scintillation crystal. Then, the MC simulation was used to derive the signal and the background we would measure from a small tumor embedded in the patient body if one of the selected radionuclides is used. ResultsBased on the criterion of detectability of a 0.1 ml tumor for a counting interval of 1 s and an administered activity of 3 MBq/kg, the current probe yields a detectable signal over a wide range of Standard Uptake Values (SUVs) and tumor-to-non-tumor activity-concentration ratios (TNRs) for 31Si, 32P, 97Zr, and 188Re. Although efficient counting of 83Br, 133I, and 153Sm proved somewhat more problematic, the foregoing criterion can be satisfied for these isotopes as well for sufficiently high SUVs and TNRs.

Investigation of the factors affecting the consistency of short-period traffic counts

The main intent of this study is to investigate the accuracy of short-duration traffic counts conducted during winter months. The investigation is based on 11-year sample data collected using permanent traffic counters at various locations in Alberta, Canada. Four types of road sites: commuter, regional commuter, rural long-distance, and recreational sites are studied. The sample data constitute six different durations of counts (12-, 24-, 48-, 72-, 96-h, and 1 week) taken during summer and winter months. The coefficient of variation (CV) is used as the relative measure of deviation for counts of different durations to measure the accuracy of short-period traffic counts. The study results indicate that 48-h count seems to be the most cost-effective counting interval during both summer and winter months. It is also found that the lowest values of CV result for counts taken at commuter sites, and the highest values are observed for recreational sites. Frequent changes in temperature and other weather events cause significant variation in traffic volume, which results in an increase in CV values for counts taken during winter months. The application of an adjustment factor to remove the effect of cold and snow from short-period counts is also included in this study. Introduced adjustment factors can reduce the values of CV for all counts taken during winter months. The findings of this study can lead highway agencies to improve the cost-effectiveness of their short-period traffic counting programs.

Study of a M/T Method of Variable Sampling Period and its Implementation Based on STM32 MPUs

In this paper, a new M/T method of variable sampling period is introduced for speed measurements by optical incremental encoders. In this method, we estimated the number of encoder pulses to count in next counting interval at the end of every sample period, so the sampling intervals were variable. Both encoder pulse and high frequency clock pulse were counted in the variable intervals and the counting of clock pulses begins and ends at the exact rising age of the encoder pulse. Through this method, the error is only one clock pulse which is much shorter than encoder pulse, which guarantees a more accurate speed measurement and rapid response of motor system.

Investigating the time dynamics of photon sequences scattered by tracer particles immersed in a polymeric gel

By dynamic light scattering, we study the effects of spatial confinement of tracer colloidal particles immersed in polyacrylamide networks on the time dynamics of sequences of elapsed times of scattered photons. We vary the degree of particles spatial confinement by changing the concentration of crosslinker in solution, from 0 to 2% in monomer mass fraction, which allows us to change the elasticity of the polymer gel. By calculating the Allan factor of the point processes of scattered photons arrival times, we are able to characterize the statistical properties of the scattering process. For all the samples we find that: i) the statistics of the photon arrival times is not Poissonian but clusterized in a certain counting time interval; ii) the time dynamics of the photon sequences is fractal in an ample range of counting times, from ∼10−3 to ∼10−1 s, with scaling exponents ranging between ∼1.7 and ∼1.0; iii) the crosslinking density of the polymer network, and thus, the system elasticity is correlated with the value of the fractal exponent. The value of the fractal exponent decreases as the system elasticity, or tracer's spatial confinement, increases.

Increasing the accuracy and temporal resolution of two-filter radon–222 measurements by correcting for the instrument response

Abstract. Dual-flow-loop two-filter radon detectors have a slow time response, which can affect the interpretation of their output when making continuous observations of near-surface atmospheric radon concentrations. While concentrations are routinely reported hourly, a calibrated model of detector performance shows that ∼ 40 % of the signal arrives more than an hour after a radon pulse is delivered. After investigating several possible ways to correct for the detector's slow time response, we show that a Bayesian approach using a Markov chain Monte Carlo sampler is an effective method. After deconvolution, the detector's output is redistributed into the appropriate counting interval and a 10 min temporal resolution can be achieved under test conditions when the radon concentration is controlled. In the case of existing archived observations, collected under less ideal conditions, the data can be retrospectively reprocessed at 30 min resolution. In one case study, we demonstrate that a deconvolved radon time series was consistent with the following: measurements from a fast-response carbon dioxide monitor; grab samples from an aircraft; and a simple mixing height model. In another case study, during a period of stable nights and days with well-developed convective boundary layers, a bias of 18 % in the mean daily minimum radon concentration was eliminated by correcting for the instrument response.

Binary Interval Search: a scalable algorithm for counting interval intersections

The comparison of diverse genomic datasets is fundamental to understand genome biology. Researchers must explore many large datasets of genome intervals (e.g. genes, sequence alignments) to place their experimental results in a broader context and to make new discoveries. Relationships between genomic datasets are typically measured by identifying intervals that intersect, that is, they overlap and thus share a common genome interval. Given the continued advances in DNA sequencing technologies, efficient methods for measuring statistically significant relationships between many sets of genomic features are crucial for future discovery. We introduce the Binary Interval Search (BITS) algorithm, a novel and scalable approach to interval set intersection. We demonstrate that BITS outperforms existing methods at counting interval intersections. Moreover, we show that BITS is intrinsically suited to parallel computing architectures, such as graphics processing units by illustrating its utility for efficient Monte Carlo simulations measuring the significance of relationships between sets of genomic intervals. https://github.com/arq5x/bits.

A Reconfigurable Multichannel Capacitive Sensor Array Interface

The design of a reconfigurable capacitive sensor array interface comprised of a subsystem able to read an array of capacitive-type sensors and an embedded processor is described. Each sensor is connected to a ring oscillator, which translates capacitive changes into a variable-frequency pulse train. An in-depth analysis of the oscillator behavior including all parasitic elements has been performed, and the use of a Schmitt trigger at the inverter chain is proposed to assure oscillation for capacitance values ranging from 1 to 1500 pF. The oscillation frequency is estimated by using a 16-b counter and the appropriate user-defined counting interval ranging from a few microseconds to several seconds in order to achieve maximum accuracy within the entire capacitance range. The 2-B word thus produced can be sent to a host computer through a serial or parallel interface for further processing. To demonstrate the concept, a 16-channel interface has been described in a hardware description language and implemented on a complex programmable logic device. Measurement of two different capacitive pressure sensors developed in-house reveals frequency sensitivity values of -252.1 and -9.54 Hz/fF, which are in good agreement with the expected values derived by the analytic relations.

Statistical properties of several models of fractional random point processes

Statistical properties of several models of fractional random point processes have been analyzed from the counting and time interval statistics points of view. Based on the criterion of the reduced variance, it is seen that such processes exhibit nonclassical properties. The conditions for these processes to be treated as conditional Poisson processes are examined. Numerical simulations illustrate part of the theoretical calculations.