Counting Efficiency Research Articles

The Contributions to Registration Efficiency of The Fast Neutron Reactions on The Nuclei of The Heavy Oxide Scintillators

The results of the study of the contributions of the interaction reactions of fast neutron sources of 239Pu-Be and 252Cf to the counting efficiency of registration by oxide scintillators CdWO4, ZnWO4, Bi4Ge3O12 and Gd2SiO5, presented. The amount of gamma quanta per input neutron emitted from final nuclei excited in the reactions of inelastic scattering (n, nʹγ)in, resonant scattering (n, n)res and capture (n, γ)res and radiation capture (n, γ)cap was measured. PMT R1307 operating in single-electron mode was used as a photodetector, the background rate was ~ 5*103 s-1. The measured efficiency ε for scintillators ø40x40 mm was 752 for ZWO, 532 for CWO, 37 for GSO, and 23 for BGO in "counts/neutron" units, measurement error rate ~ 3-5%. The formation of the detector response is influenced by the parameters of the scintillator nuclei, such as the values of the interaction cross sections in the resonance region, the density of nuclear levels of the final nuclei, the lifetime of excited nuclear states, the upper limit of the resonance region of the cross section, as well as the scintillation time and geometric parameters of the scintillators. A phenomenological model of the response of an oxide scintillator to fast neutrons is proposed.

Artificial intelligent identification of apatite fission tracks based on machine learning

Over the past half century, apatite fission track (AFT) thermochronometry has been widely used in the studies of thermal histories of Earth’s uppermost crust. The acquired thermal histories in turn can be used to quantify many geologic processes such as erosion, sedimentary burial, and tectonic deformation. However, the current practice of acquiring AFT data has major limitations due to the use of traditional microscopes by human operators, which is slow and error-prone. This study uses the local binary pattern feature based on the OpenCV cascade classifier and the faster region-based convolutional neural network model based on the TensorFlow Object Detection API, these two methods offer a means for the rapid identification and measurement of apatite fission tracks, leading to significant improvements in the efficiency and accuracy of track counting. We employed a training dataset consisting of 50 spontaneous fission track images and 65 Durango standard samples as training data for both techniques. Subsequently, the performance of these methods was evaluated using additional 10 spontaneous fission track images and 15 Durango standard samples, which resulted in higher Precision, Recall, and F1-Score values. Through these illustrative examples, we have effectively demonstrated the higher accuracy of these newly developed methods in identifying apatite fission tracks. This suggests their potential for widespread applications in future apatite fission track research.

Application of portable liquid scintillation counter for on-field measurement of tritium in aqueous samples during radiation emergency

Screening of aqueous samples for 3H contamination is required to decide suitability of water intended for human consumption during radiation emergency. BARC, Trombay has recently procured Portable Triathler liquid scintillation counter as a screening tool for on-site response to radiation emergency. For this purpose, parameters like, different available scintillators, scintillator to sample ratio and influence of different capacity scintillation vials were optimized for 3H concentration measurement. The study indicated that for 7 mL vials, the optimized scintillator to sample ratio was 4:1 for Optiphase Hisafe II, Ultima Gold Ultra Low Level Tritium, Aqualight AB and Dioxane based scintillators whereas for Ultima Gold AB and Optiphase Hisafe III scintillators it was 3:1. In case of 20 mL vials, the ratio was optimized to 8:1 for all the above mentioned six scintillators. Additionally, the effect of applying counting efficiency using calibration curves generated using distilled water and that obtained using optimized scintillator to sample ratio in various spiked water samples was also studied. Results in 3H concentration (2000–5700 Bq/mL) indicate about ±10% deviation using both the methods for commercially available scintillators. However, in case of Dioxane based scintillator, the deviation was higher (20%). For analysis of 3H concentration ∼200 Bq/mL using commercially available scintillators results in higher deviation of about 21% due to unreliable quench indicating parameter for count rate less than 4000. The study indicated that calibration curves constructed using optimized parameters are universally applicable for determination of 3H concentration in wide variety of water samples.

Efficient and precise cell counting for RNAi screening of Orientia tsutsugamushi infection using deep learning techniques

Acquiring fluorescent scrub typhus images obtained through RNA interference screening for the analysis of 60 different human genes and 18 control genes poses challenges due to nonuniform or clumped cells and variations in image quality, rendering image processing (IP) counting inadequate. This study addresses three key questions concerning the application of deep learning methods to this dataset. Firstly, it explores the potential for object detection (OD) models to replace instance segmentation (IS) models in cell counting, striking a balance between accuracy and computational efficiency. Object detection models, including Faster R-CNN, You Only Look Once (YOLO), and Adaptive Training Sample Selection (ATSS) with reduced backbone sizes, outperform the instance segmentation model (Mask Region-Based Convolutional Neural Network: Mask R-CNN, Cascade Mask-RCNN) with both deep and shallow backbones. Notably, ATSS with Resnet-50 achieves an impressive mean average precision of 0.884 in just 33.1 milliseconds. Secondly, reducing the feature extractor size enhances cell counting efficiency, with OD models featuring reduced backbones demonstrating improved performance and faster processing. Finally, deep learning, especially OD models with shallow backbones, outperforms IP methods in both absolute and relative cell counting. This study demonstrates the potential for OD models to replace IS models, the efficiency gains achieved through the reduction of feature extractors, and the superiority of DL over IP in cell counting tasks.

Determination of carbon-14 in marine biota using oxidation combustion and gel suspension liquid scintillation counting

In this study, we report a new analytical method for determination of 14C in marine biota utilizing oxidation combustion separation combined with CaCO3 suspension of precipitates for liquid scintillation counting (LSC). The main factors affecting the oxidation combustion efficiency of tube combustion furnace and the counting efficiency of the LSC were systematically investigated and optimized. Under the optimal combustion conditions, the combustion recovery of carbon ranged from 85.6 % to 92.4 % for five marine samples. And the method achieved a detection limit of 0.13 Bq/g for 14C and repeatability of 3.9–9.1 %. The analytical turnover time was 6 h, and up to six samples could be processed simultaneously. Assessment of uncertainty components showed that the uncertainty in counting was the largest contributor, followed by combustion recovery and counting efficiency. The developed method enables reliable measurement of 14C in marine biota, providing valuable analytical tool for risk assessment purposes.

PSXI-12 In Vitro Assessment of Binding Agents as an Alternative to Activated Charcoal for the Prevention of Boar Taint

Abstract Boar taint is an off odor and flavor that occurs once meat from uncastrated male pigs is heated, and results from the deposition of androstenone in the fat. Androstenone circulates between the liver and gut via the enterohepatic circulation, where it can be recirculated back to the liver or deposited in the fat. Previous studies from our lab have demonstrated that adding activated charcoal (AC) to feed is effective at disrupting enterohepatic circulation and preventing boar taint; however, AC is expensive and currently not approved for use as a feed additive. Spent filter aid (SFA) is a byproduct of corn syrup production, contains up to 33% diatomaceous earth (DE), and can be used as an energy source. DE and biochar have been used to bind toxins in the gastrointestinal tract and have a high surface area and porosity like that of AC. Additionally, biochar is approved and used as a feed additive in cattle production, and both biochar and SFA are available at a much lower cost. Therefore, the objective of this study was to evaluate the androstenone binding efficiency of SFA and biochar in vitro to assess their suitability as potential dietary treatments for preventing boar taint. AC, biochar and SFA were incubated for 30 minutes at 37℃ with radiolabeled androstenone, estrone sulphate (E1S), or estrone (E1) dissolved in buffer. Following incubation, the unbound radioactive steroid fraction was quantified using a scintillation counter and binding efficiency was calculated using a modified Michaelis-Menten equation. Statistical analysis was conducted with a 2-way ANOVA in SAS with Tukey-Kramer’s post hoc test. The binding efficiency (Bmax/K) of AC was greater than both biochar (P < 0.0001) and SFA (P < 0.0001). However, the maximum binding (Bmax) of androstenone by AC (97.30% ± 0.44) was 13% greater than that of biochar (84.53% ± 0.79) and nearly double that of SFA (50.50% ± 0.22). Of the binding agents tested, SFA had some selective binding for androstenone as the Bmax for androstenone was greater than both E1S (P < 0.0001) and E1 (P = 0.0013). These results suggest that biochar may be a suitable alternative to AC for use as a feed additive as it can bind high concentrations of androstenone, and its binding characteristics were most like AC. Future animal studies are needed to evaluate the effects in vivo to assess the efficacy of biochar as a dietary treatment for boar taint.

Primary standardization and half-life determination of [formula omitted]Ac at NRC

A solution of 225Ac was standardized by NRC using the triple-to-double coincidence ratio (TDCR) method. The counting efficiencies were calculated assuming a counting efficiency of 100% for alpha decays and those calculated using the MICELLE2 Monte Carlo code for beta decays and was approximately 500% for the NRC TDCR system. The relative uncertainty for the activity concentration was determined to be 0.25%. This agreed with measurements performed using gamma spectroscopy and a predicted calibration factor for the Vinten 671 ionization chamber as calculated using an EGSnrc model, implementing radioactive decay. Finally, the half-life of 225Ac was determined from long-term measurements using ionization chambers and liquid scintillation counting. The NRC measured half-life for 225Ac was found to be 9.914(4) days and is consistent within an expanded uncertainty coverage of k = 2 with the most recent (Kossert et al., 2020; Pommé et al., 2012) measurements of this decay parameter.

Automated Spot Counting in Microbiology.

Biological samples are routinely analyzed for microbe concentration. The samples are diluted, loaded onto established host cell cultures, and incubated. If infectious agents are present in the samples, they form circular spots that do not contain the host cells. Each spot is assumed to be originated from a single microbial unit such as a bacterial colony forming unit or viral plaque forming unit. The undiluted sample concentration is estimated by counting the spots and back-calculating. Counting the number of spots by trained technicians is currently the gold standard but it is laborious, subjective, and hard to scale. This paper presents a new automated algorithm for spot counting, Localized and Sequential Thresholding (LoST). Validation studies showed that LoST performance was comparable with manual counting and outperformed several existing tools on images with overlapping spots. The LoST algorithm employs sequential thresholding through a two-stage segmentation and borrows information across all images from the same dilution series to fine-tune the count and identify right censoring. The algorithm increases the efficiency of the spot counting and the quality of the downstream analysis, especially when coupled with an appropriate statistical serial dilution model to enhance the undiluted sample concentration estimation procedure.

A spherical neutron long counter for 4[formula omitted] neutron detection in the energy range of 0.01 eV to 20 MeV

Neutron detection using a long counter is the most commonly used method for accurate neutron flux measurement. It is desirable to design a long counter with a flat energy response and a consistent angular response. This requires counters to have neutron-energy-independent efficiency over a wide range of energies and a very slight dependence on the direction of neutron incidence in the 4π space. In this work, we designed a spherical neutron long counter using the Monte Carlo method, with a model consisting of a polyethylene ball, built-in air rings, and boron carbide material. The internal air rings enhance the energy response of thermal neutrons, spherical polyethylene improves the energy response of fast neutrons, and boron carbide material solves the problem of high local neutron energy response. We analyzed the energy response, angular response, and detection efficiency of long counters using neutron sources such as Pu–Be and Am–Be. The results show that the neutron energy response is relatively flat in the energy region of 0.01 eV to 20 MeV, the angular response is consistent in 2π space, and the maximum relative angular response deviation in 4π space is no more than 16.5%. We focus on the applicability of long counters in complex neutron fields, such as scattered neutron fields, and provide a reference for their use of long counters in neutron detection.

Machine Vision Method for Quantitative Statistics Analysis of Industrial Product Images

To address the problems of unstable accuracy, low efficiency, and subjective influence of manual counting, a machine vision-based method to count the quantity of tobacco shreds is proposed for the first time. In this paper, the complex tobacco shred image is obtained by backlight imaging. The adaptive threshold segmentation method is used to segment tobacco shreds. The pixel area of the tobacco shred area is calculated by connected domain labelling. Second, independent tobacco shreds and adhesive tobacco shreds were identified based on the pixel area, and the quantity of segmented tobacco shreds was counted for the first time. Subsequently, in complex scenarios (such as tobacco shreds adhesive and overlapping), an image is usually obtained by manually drawing the contours of the adhesive and overlapping tobacco shreds on the basis of primary statistics. Finally, different individuals are distinguished, segmentation is completed, and tobacco shred quantity statistics are realised. The experimental results show that the average accuracy is 100.0 % for quantitative statistics of independent tobacco shred images. For tobacco shred images with adhesive and overlapping interference, the minimum accuracy is 90 %, and the accuracy increases with the increase in tobacco shred quantity. Furthermore, the efficiency of the tobacco shred quantity statistics conducted by the method in this paper was only affected by complex scenarios. Compared to artificial processing, the efficiency was increased by more than 100 %. The work in this paper can provide the technical basis for measuring the dimensions of tobacco shreds.

Pressure-dependent performance of two CEN-specified condensation particle counters

Abstract. One of the most important parameters to quantify an aerosol is the particle number concentration. Condensation particle counters (CPCs) are commonly used to measure the aerosol number concentration in the nanometer size range. To compare the data from different measurement stations and campaigns, it is important to harmonize the instrument specifications, which is why the CEN/TS 16976:2016 technical specification was introduced for CPCs. Therein, the parameters of the CEN CPC are specified for standard pressure and temperature. However, CEN CPCs are used in various surroundings, on high mountains or on airplanes, where they are exposed to low-pressure conditions. Here, we present the pressure-dependent performance (including the concentration linearity and counting efficiency) of two different models of CEN CPCs, the Grimm 5410 CEN and the TSI 3772 CEN. We found that their performance at 1000 and 750 hPa was in accordance with the CEN technical specifications. Below 500 hPa, the performance decreased for both CPC models, but the decrease was different for the two models. To gain insight into the performance of the two CPC models, we performed a simulation study. This study included simulations of the saturation profiles and calculations of internal particle losses within the CPCs. The simulations reproduced the overall performance decrease with decreasing pressure and reveal that the internal structure of the CPC has a significant influence on the performance. We anticipate our publication to provide a deeper understanding of the counting efficiency of CPCs and their pressure dependence. Our findings might be a starting point for new standards that include the pressure-dependent performance, or they could help in designing new CPCs.

Design of a high counting efficiency sensor for 1.0 cubic feet per minute laser particle counter.

Based on the theory of Mie scattering, an optical sensor for a 1.0 cubic feet per minute laser particle counter is developed in this paper. First, an illumination optical path relying on aspherical lens and cylindrical lens for laser shaping was designed, and a narrow optical spot with the illumination in the vertical direction of the photosensitive area approximately distributed as a flat top was obtained. Second, the scattering light path was designed by using the theory of Mie scattering and geometric optics method. Then, the structure of the sampling air path was designed with reference to the principle of Laval nozzle, and the particle flow trajectory was verified by simulation using the fluid dynamics software Ansys Fluent. Finally, the performance of the optical sensor was measured with polystyrene latex (PSL) particles, and the results showed that the counting efficiency of the 0.3μm particle size channel met the requirement of 50% ± 20% and the 0.5μm particle size channel met the requirement of 100% ± 10%, which complied with the ISO 21501-4 standard.

An Advanced Optimization Method to Minimize the Detection Limit of Liquid Scintillation Counter to Measure Low-Level Tritium Activity in Groundwater

In arid regions, the tritium concentration in groundwater is typically very low and often falls below the minimum detectable activity (MDA) of the conventional liquid scintillation counter (LSC). Therefore, to measure the tritium activity concentration, it is necessary to lower the detection limit so that the scintillation counter can detect it. In the present study, several methods are discussed which are effective at lowering the detectable activity of tritium. One of these methods is to enrich the tritium activity concentration by ten- to fortyfold of the initial concentration of the tritium. Twelve spiked samples with known amounts of tritium, five with high concentrations and seven with low concentrations, were enriched by the electrolysis process. The results indicated that enriching the tritium levels in groundwater lowers the MDA value. Other methods are minimizing background radiation using low-background materials for sample containers, increasing the measurement efficiency of the scintillation counter and counting time, and shielding the sample from environmental radiation using the shutter option in LSC. Moreover, reducing the number of interfering contaminants in the sample can lower the uncertainty in measuring the tritium concentration in the water sample, which is beneficial for detecting low-level tritium in water to ensure public health and safety.

Characterisation of a self-sustained, water-based condensation particle counter for aircraft cruising pressure level operation

Abstract. Aerosol particle number concentration measurements are a crucial part of aerosol research. Vertical profile measurements and high-altitude/low-pressure performance of the respective instruments become more important for remote sensing validation and a vital tool for the observation of climate variables. This study tests the new, commercially available water condensation particle counter (MAGIC 210-LP) for the deployment at aircraft cruising pressure levels that the European research infrastructure IAGOS (In-service Aircraft for a Global Observing System; http://www.iagos.org, last access: 2 May 2023) is aiming for by operating measurement instrumentation onboard passenger aircraft. We conducted laboratory experiments for conditions to simulate passenger aircraft flight altitude at operation pressure. We demonstrate that this type of water condensation particle counter shows excellent agreement with a butanol-based instrument used in parallel. A Faraday cup aerosol electrometer serves as the reference instrument. Experiments are performed with test aerosol ammonium sulfate and fresh combustion soot at pressure levels ranging from 700 to 200 hPa. For soluble particles like ammonium sulfate, the 50 % detection efficiency cut-off diameter (D50) is around 5 nm and does not differ significantly for all performed experiments. For non-soluble fresh soot particles, the D50 cut-off diameter of approximately 10 nm does not vary substantially as a function of pressure, whereas the 90 % detection efficiency cut-off diameter D90 increases from 19 nm at 700 hPa to 37 nm at 200 hPa. The overall counting efficiency for particles larger than 40 nm reaches 100 % for working pressures of 200 hPa and higher.

Efficiency calibration and optimization of a liquid scintillation spectrometer for low level 55Fe and 63Ni measurements

An experimental study on the counting efficiency, background, and Lower Limit of Detection (LLD) of a liquid scintillation spectrometer was carried out for establishing a measurement technique suitable for low level activity measurements of 55Fe and 63Ni in environmental samples. The spectrometer's response, using two scintillators (PerkinElmer Optiphase Hisafe 3 and Meridian Prosafe HC+) and glass and plastic vials, was studied. Colour and chemical quenching effects were also investigated for both scintillators and vials. Finally, a spectrum integration window selection method able to reduce the LLD through a Figure of Merit (FOM) optimization, was tested. Efficiency and LLD curves were obtained for both scintillators and types of vials with this technique.

A bilateral comparison between LNHB and PTB to determine the activity concentration of the same 125I solution

A bilateral comparison to determine the activity concentration of the same 125I solution was organized. As electron-capture radionuclide with a rather high atomic number, 125I must be regarded as difficult to measure. The situation is partly exacerbated by the fact that some established standardization methods, like photon-photon coincidence counting, can no longer be applied due to the unavailability of appropriate equipment and expertise.One aim of this work is to compare modern liquid scintillation counting methods for the standardization of 125I. Both participating metrology institutes have used their custom-built triple-to-double-coincidence ratio (TDCR) counters and the determined activity concentrations are in excellent agreement even though the ways to analyze the data and to compute counting efficiencies were widely independent. The results also agree with the outcome of 4π-γ counting that was carried out at LNHB.In both laboratories, the measurements were complemented by measurements with several secondary standardization methods which even allow to establish a link to the CCRI(II)–K2.I-125(2) comparison started in 2004. A good agreement between the TDCR results and the key comparison reference value of the 2004/2005 comparison was obtained.

A new working fluid for condensation particle counters for use in sensitive working environments

Abstract. The working fluid of a condensation particle counter (CPC) is one of its essential characteristics. Butanol is commonly used as the working fluid in alcohol-based CPCs due to its proven performance for various applications and for a wide range of working conditions over the past almost 5 decades. At the same time, butanol has several disadvantages, including its strong and unpleasant odour, negative effects when inhaled over prolonged periods and flammability, making it troublesome to use in places with strict safety regulations. In this work, we propose addressing these negative issues by replacing butanol with dimethyl sulfoxide (DMSO), a substance that has not been used as a CPC working fluid to date. DMSO is an odourless, non-flammable and non-toxic substance that is easily accessible and inexpensive. During thorough experiments, this new substitute working fluid has proven to be stable with respect to its performance for CPCs and storage. We show that DMSO behaves in an equivalent manner to butanol when used to operate a CPC in terms of the instrument's counting efficiency, D50 cut-off diameter (the diameter at which 50 % of the particles are counted with respect to a reference) and concentration linearity. In addition, we have demonstrated this for operating pressures ranging from ambient pressure down to 200 hPa without the need for any safety precautions. Our new working fluid was tested on three CPC units representing two different models, almost always in side-by-side measurements. So far, we have achieved the best results with operating temperatures of 40 ∘C for the CPC's saturator and 5 ∘C for its condenser. To address a less desirable property of DMSO, it could be mixed with a slight amount of water to decrease its freezing point significantly. When mixed accordingly, the substance remains a liquid, even in work environments with temperatures ≤ −10 ∘C, without any impact on the CPC's counting efficiency performance.

Effect of Durian By-Product on Nutrition Intake, Productivity, and Physiological Conditions of Kacang Goats (Capra aegagrus hircus)

The native plant of mainland Asia, Durian, presents a considerable opportunity to be used as animal feed due to the high by-product production, with almost 70% of every durian fruit being waste. This presents an excellent opportunity to repurpose durian skin and seeds as animal feed. An experiment was conducted to evaluate the impact of durian by-product on the productivity and physiological condition of kacang goats. The research was conducted from September to November 2020 at the Experimental Cage owned by CV. Prima BREED, Palu City, Central Sulawesi Province. The research cages were stage cages, with a size of 2 x 10 m, and one animal was placed in each cage. A total of 18 Peanut goats were divided into 3 treatment levels and 6 replications according to a completely randomized design. The study found that the nutritional intake of durian by-product in the form of rind and seed flour as much as 0.5% in the feed affected the carcass percentage, the amount of red blood cell, hemoglobin level, and hematocrit value but had no effect on body weight gain, dry matter consumption, feed use efficiency, carcass weight, weight and percentage of non-edible carcasses, body temperature, respiration frequency, pulse frequency, and white blood cell count of kacang goats. This indicates that the utilization of 0.5% durian by-product (seeds and rind) in feed did not have a negative effect on the productivity and physiological condition of kacang goats, making it a viable option for animal feed.

Development of a 2D digital proton–proton scattering technique for hydrogen depth profiling

Measuring hydrogen concentration and determining its depth profile in different substrates has always been a major challenge for material science. Proton–proton scattering is a nondestructive technique for hydrogen analysis in thin samples. In this paper, the development of a 2D coincidence proton–proton spectroscopy was performed using a 3 MeV Van de Graaff accelerator. In the presented technique, the coincidence recording of the proton–proton scattering events by a waveform digitizer provides the sum‐difference energy spectrum of the correlated events. By determining the proton energy loss in the sample, the hydrogen depth profile was extracted. To correct the error in the counting efficiency due to the multiple scattering, the Monte Carlo simulation was performed using the Corteo code. The performance of the technique was tested by measuring the concentration of hydrogen on both sides of a thin layer of aluminum. The results confirmed that the established technique is sensitive enough to separate the hydrogen peaks of these two thin layers.

How to Improve the Efficiency of Check-In Counter: A Counter-Sharing Method

Improving the efficiency of check-in counters is a significant concern for airport operation management departments and airline companies. However, the existing studies mainly optimize the counter allocation based on the number of counters and airport demands, which needs more exploration on improving the utilization rate of check-in counters under the condition of unchanged resource allocation. In this paper, we propose a counter-sharing method to improve check-in efficiency by sharing the idle check-in counters in the adjacent check-in area. In the proposed counter-sharing method, we first define the passenger’s total walking distance and waiting time for queues as the metrics, then reassign the check-in areas and adjust the internal departure sequence of flights to maximize the counter-sharing rate. The numerical results indicate that the proposed counter-sharing method can improve the efficiency of check-in counters and reduce the passenger’s total walking distance and waiting time in the queue during the check-in process, which can enhance the airport’s operation efficiency and competitiveness.