Low-noise and low-power pixel sensor chip for gas pixel detectors

Topmetal-M2 is a large-area pixel sensor chip fabricated using the GSMC 130 nm CMOS process in 2021.The pixel array of Topmetal-M2 consists of pixels of 400 rows×512 columns with a pixel pitch of 45μm×45μm.The array is divided into 16 subarrays,with pixels of 400 rows×32 columns per subarray.Each pixel incorporates two charge sensors:a diode sensor and a Topmetal sensor.The in-pixel circuit primarily consists of a charge-sensitive amplifier for energy measurements,a discriminator with a peak-holding circuit,and a time-to-amplitude converter for time-of-arrival measurements.The pixel of Topmetal-M2 has a charge input range of~0-3 k e-,a voltage output range of~0-180 mV,and a charge-voltage conversion gain of~59.56μV∕e-.The average equivalent noise charge of Topmetal-M2,which includes the readout electronic system noise,is~43.45 e-.In the scanning mode,the time resolution of Topmetal-M2 is 1 LSB=1.25μs,and the precision is^()7.41μs.At an operating voltage of 1.5 V,Topmetal-M2 has a power consumption of~49 mW∕cm~2.In this article,we provide a comprehensive overview of the chip architecture,pixel working principles,and functional behavior of Topmetal-M2.Furthermore,we present the results of preliminary tests conducted on Topmetal-M2,namely,alpha-particle and soft X-ray tests.

CVTD: A Robust Car-Mounted Video Text Detector

Text perception is crucial for understanding the semantics of outdoor scenes,making it a key requirement for building intelligent systems for driver assistance or autonomous driving.Text information in car-mounted videos can assist drivers in making decisions.However,Car-mounted video text images pose challenges such as complex backgrounds,small fonts,and the need for real-time detection.We proposed a robust Car-mounted Video Text Detector(CVTD).It is a lightweight text detection model based on ResNet18 for feature extraction,capable of detecting text in arbitrary shapes.Our model efficiently extracted global text positions through the Coordinate Attention Threshold Activation(CATA)and enhanced the representation capability through stacking two Feature Pyramid Enhancement Fusion Modules(FPEFM),strengthening feature representation,and integrating text local features and global position information,reinforcing the representation capability of the CVTD model.The enhanced feature maps,when acted upon by Text Activation Maps(TAM),effectively distinguished text foreground from non-text regions.Additionally,we collected and annotated a dataset containing 2200 images of Car-mounted Video Text(CVT)under various road conditions for training and evaluating our model’s performance.We further tested our model on four other challenging public natural scene text detection benchmark datasets,demonstrating its strong generalization ability and real-time detection speed.This model holds potential for practical applications in real-world scenarios.

Study on the Performance of the GRANDProto300 Particle Detector Array by Simulation

The Giant Radio Array for Neutrino Detection(GRAND)is a proposed large-scale observatory designed to detect cosmic rays,gamma-rays,and neutrinos with energies exceeding 100 Pe V.The GRANDProto300 experiment is proposed as the early stage of the GRAND project,consisting of a hybrid array of radio antennas and scintillator detectors.The latter,as a mature and traditional detector,is used to cross-check the nature of the candidate events selected from radio observations.In this study,we developed a simulation software called G4GRANDProto300,based on the Geant4 software package,to optimize the spacing of the scintillator detector array and to investigate its effective area.The analysis was conducted at various zenith angles under different detector spacings,including 300,500,600,700,and 900 m.Our results indicate that,for large zenith angles used to search for cosmic-ray in the GRAND project,the optimized effective area is with a detector spacing of 500 m.The G4GRANDProto300 software that we developed could be used to further optimize the layout of the particle detector array in future work.

Countermeasure against blinding attack for single-photon detectors in quantum key distribution

Quantum key distribution(QKD),rooted in quantum mechanics,offers information-theoretic security.However,practi-cal systems open security threats due to imperfections,notably bright-light blinding attacks targeting single-photon detectors.Here,we propose a concise,robust defense strategy for protecting single-photon detectors in QKD systems against blinding attacks.Our strategy uses a dual approach:detecting the bias current of the avalanche photodiode(APD)to defend against con-tinuous-wave blinding attacks,and monitoring the avalanche amplitude to protect against pulsed blinding attacks.By integrat-ing these two branches,the proposed solution effectively identifies and mitigates a wide range of bright light injection attempts,significantly enhancing the resilience of QKD systems against various bright-light blinding attacks.This method forti-fies the safeguards of quantum communications and offers a crucial contribution to the field of quantum information security.

High-speed performance self-powered short wave ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)

High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with Pt contacts were demonstrated and their properties were studied in detail.Theκ(ε)-Ga_(2)O_(3)layers were deposited by the halide vapor phase epitaxy on patterned GaN templates with sapphire substrates.The spectral dependencies of the photoelectric properties of struc-tures were analyzed in the wavelength interval 200-370 nm.The maximum photo to dark current ratio,responsivity,detectiv-ity and external quantum efficiency of structures were determined as:180.86 arb.un.,3.57 A/W,1.78×10^(12) Hz^(0.5)∙cm·W^(-1) and 2193.6%,respectively,at a wavelength of 200 nm and an applied voltage of 1 V.The enhancement of the photoresponse was caused by the decrease in the Schottky barrier at the Pt/κ(ε)-Ga_(2)O_(3)interface under ultraviolet exposure.The detectors demon-strated could functionalize in self-powered mode due to built-in electric field at the Pt/κ(ε)-Ga_(2)O_(3)interface.The responsivity and external quantum efficiency of the structures at a wavelength of 254 nm and zero applied voltage were 0.9 mA/W and 0.46%,respectively.The rise and decay times in self-powered mode did not exceed 100 ms.

Determination of Benzo[a]pyrene in Edible Oil by High Performance Liquid Chromatography-Fluorescence Detector (HPLC-FL)

In this study, an optimized high performance liquid chromatography-fluorescence detector (HPLC-FL) method for the determination of benzo[a]pyrene in edible oil was established. HPLC was performed with Thermo Fisher Scientific C18 column (250 mm×4.6 mm, 5 μm) as the chromatographic column and acetonitrile and water as the mobile phase, and the excitation wavelength and emission wavelength of fluorescence detector were 286 and 430 nm, respectively. The response was high, and the linear range was 0.5-10.0 ng/ml. The lowest limit of detection was 0.11 ng/ml, and the average recovery was 92.5%. This method is suitable for quantitative analysis of benzo[a]pyrene content in edible oil.

宁夏水贫困地域分异的WPI-Geodetector测度与分析

水贫困是长期以来备受西北地区关注的焦点问题。以宁夏为典型案例,通过建立水贫困评价指标体系,采用WPI模型计算2011—2015年区域水贫困水平,并运用地理探测器诊断出水贫困分异的主导因素,揭示水贫困动力机制,总结出水贫困地域类型。结果表明:(1)水贫困指数时空分异显著。宁夏WPI值由2011年的0.393上升到2015年的0.404,水贫困呈现缓慢改善态势,但地区差距在扩大。(2)水贫困主导因素时空变化明显。从目标层看,资源系统对宁夏水贫困影响最大,但其决定力在变小;环境系统的决定力在增大;使用系统的决定力最小。从指标层看,年降水量等10个指标q值始终在0.8以上,而年径流深等7个指标对宁夏水贫困决定力在下降。从分地区看,银川市水贫困指数分异决定力q值>0.5的有6个指标,需要提高用水效率、降低用水压力和合理配置生态用水;石嘴山市水贫困指数分异决定力q值>0.5的有11个指标,客观表明作为资源型地区发展转型过程中的矛盾所在;吴忠市水贫困指数分异决定力q值>0.5的有13个指标,今后着力要加强用水效率、用水管理和水资源高效利用水平等的统筹协调;固原市水贫困指数分异决定力q值>0.5的有4个指标,重点要提高设施水平和污染治理能力;中卫市水贫困指数分异决定力q值>0.5的有15个指标,要突出提高用水效率和设施水平。(3)水贫困地域类型划分。在水资源共同约束背景下将研究区划分为途径(设施水平)约束型区域、能力—使用(用水管理—用水效率)约束型区域、环境(用水压力—生态环境)约束型区域等3种水贫困地域类型。

基于Geodetector的滇中岩溶区石漠化空间分布特征及影响因子分析

为探究滇中岩溶区石漠化在不同影响因子上的空间分布特征以及对影响因子定量归因,基于Landsat、DEM等遥感数据和社会经济数据,结合RS-GIS技术和地理探测器模型(Geodetector)获取石漠化信息和各影响因子的贡献率。结果表明:(1)滇中岩溶区石漠化总面积为3015.04 km^(2),占研究区总土地面积的5%,占岩溶面积的13.36%。(2)在不同岩性中,石漠化主要分布在碳酸盐岩与碎屑岩中,占总石漠化面积的62%;在不同土地利用方式中,石漠化主要分布在草地,占总石漠化面积的48.62%;在不同坡度下,石漠化主要分布在8°-15°范围内,占总石漠化面积的32.01%;从人口密度和第一生产总值看,石漠化主要分布在100-200人/km^(2)和>40×10^(8)元范围内,占总石漠化面积的比例分别为54.77%和44.33%。(3)地理探测器揭示了滇中岩溶区石漠化驱动因子的权重大小为:土地利用(q=0.42)>坡度(q=0.29)>岩性(q=0.17)>第一生产总值(q=0.14)>人口密度(q=0.14);交互探测器揭示了2个因子共同作用时,对石漠化形成的贡献率最大的是土地利用和坡度(q=0.58),其次是土地利用和岩性(q=0.50)。研究区石漠化在不同影响因子上的分布具有显著差异,人为和自然因素中最显著的影响因子分别是土地利用类型和坡度。

基于RFFLUS-InVEST-Geodetector耦合模型的平朔矿区生境质量时空演变及其影响因素

将土地利用模型(RFFLUS)、生态系统服务功能模型(InVEST)和地理探测器模型(Geodetector)耦合,分析平朔大型露采矿区1985—2025年土地利用变化,探索其生境质量的时空演变规律,并揭示影响生境质量的自然和人为因素。结果表明:(1)平朔矿区的主要土地利用类型为耕地、草地和建设用地;1985—2025年建设用地、草地面积增加,耕地大面积减少,耕地主要转为林地和草地,林地和水域减少较小。(2)生境质量等级分布与土地利用分布具有一致性,高质量生境主要分布于林地,低质量生境分布于建设用地;1985—2015年生境质量总体略有下降,煤矿开采是生境质量下降的主要原因;2025年仍存在生境下降风险,需要坚持生态复垦。(3)影响生境质量变化的主导影响因子是NDVI,其次为煤炭生产能力和GDP;在交互作用探测中,因子之间的交互作用均为增强,其中NDVI与GDP的交互作用最大。

基于贝叶斯时空层次模型(BSTHM)和地理探测器法(GeoDetector)对细菌性痢疾的环境风险评估

在全世界范围,细菌性痢疾是一个得到广泛关注的健康问题,具有显著的时空异质性,但大多数研究只是在某一区域单独实施了时间或空间层面的分析,其在不同地区的时空关联尚不清楚。考虑到山东省社会经济发展不平衡,东、中、西部差异明显,因此本研究首先利用贝叶斯时空层次模型(BSTHM)呈现山东省细菌性痢疾的时空异质性,其次利用地理探测器法(GeoDetector)分别从不同的区域(东、中、西部)来研究气象要素对此疾病的影响,且针对热点地区,量化社会经济要素及其两两的交互作用对其的解释力。结果表明,时间上,发病高峰出现在夏季。空间上,高风险地区主要分布在山东省东部和北部区县,且气象因子在不同地区对该病的影响也存在显著差异。山东省东部沿海地区最重要的两个主导因子是风速和日照时数,其解释力分别为0.28和0.22。山东省西部内陆地区前两个主导因子为平均温度和降水量,其解释力分别为0.47和0.32。山东省中部地区前两个主导因子为平均温度和风速,其解释力分别为0.66和0.48。本研究通过对山东省各个地区细菌性痢疾发病情况的时空异质性以及影响因素的分析发现,湿热的环境有利于细菌性痢疾的传播。另外,在热点地区,起主导作用的社会经济因子是第三产业比重,表明社会经济状况对细菌性痢疾的发病具有一定的影响作用,为本地区细菌性痢疾的控制和预防政策的制定提供理论依据,针对不同地区需要更具体的方案来预防、控制和分配医疗资源,以提高其疾病应对能力,减少该疾病造成的潜在损失。

Landslide susceptibility mapping using hybrid random forest with GeoDetector and RFE for factor optimization

The present study aims to develop two hybrid models to optimize the factors and enhance the predictive ability of the landslide susceptibility models.For this,a landslide inventory map was created with 406 historical landslides and 2030 non-landslide points,which was randomly divided into two datasets for model training(70%)and model testing(30%).22 factors were initially selected to establish a landslide factor database.We applied the GeoDetector and recursive feature elimination method(RFE)to address factor optimization to reduce information redundancy and collinearity in the data.Thereafter,the frequency ratio method,multicollinearity test,and interactive detector were used to analyze and evaluate the optimized factors.Subsequently,the random forest(RF)model was used to create a landslide susceptibility map with original and optimized factors.The resultant hybrid models GeoDetector-RF and RFE-RF were evaluated and compared by the area under the receiver operating characteristic curve(AUC)and accuracy.The accuracy of the two hybrid models(0.868 for GeoDetector-RF and 0.869 for RFE-RF)were higher than that of the RF model(0.860),indicating that the hybrid models with factor optimization have high reliability and predictability.Both RFE-RF GeoDetector-RF had higher AUC values,respectively 0.863 and 0.860,than RF(0.853).These results confirm the ability of factor optimization methods to improve the performance of landslide susceptibility models.

基于InVEST&GEO-detectors模型的会仙湿地生境质量变化及影响因素研究

喀斯特湿地是广泛分布在喀斯特地区的一种特殊的湿地类型,其生态地位举足轻重,探索喀斯特湿地生境质量变化的影响因素对喀斯特地区生态建设具有重要的意义。本文基于会仙湿地保护区2000和2020年的土地利用数据,通过InVEST模型评估会仙湿地保护区的生境质量,利用地理探测器探测影响会仙湿地保护区生境质量变化的自然和人为因素。研究结果表明:1)研究区2000至2020年建设用地明显扩张,草地和水体显著减少;2)会仙湿地保护区生境质量总体呈现下降的趋势,生境退化度有所上升,生境质量较差的区域主要集中在研究区的北部、中部和东北部;3)地理探测器识别出会仙湿地保护区生境质量空间变化受自然和人为因子的综合作用,主导影响因子是GDP(q为0.135),其次为夜间灯光指数(DMSP)(q为0.053);交互作用探测结果表明,各因子对生境质量影响呈现出双因子增强效果。研究结果有助于揭示会仙湿地保护区生境质量的时空演变过程,可针对会仙湿地生态建设的问题提出可行的应对策略。

基于PS-InSAR和GeoDetector的兰州主城区地表变形监测与驱动力分析

采用PS-InSAR技术,基于2014年12月-2017年1月的32幅Sentinel-1A卫星TOPS模式影像,获得兰州主城区地表的形变速率和时间序列形变量信息,利用GeoDetector对建成区、道路网密度、降水、气温、土地覆盖类型以及地质类型进行单因素和多因素交互的驱动力分析.结果表明,兰州市主城区地表形变速率介于-53.17~37.66 mm/a,总体较为稳定,多数区域(95.25%)的形变速率介于-5~5 mm/a.主城区地表变形是各影响因素的交互驱动,而不是单一因素的驱动,建成区∩道路网密度是主城区地表形变的主要影响因素.将GeoDetector方法应用于各驱动力对城市地表形变的解释力,为研究城市地表形变影响因素分析提供了新的思路.

Quantification of Effects of Natural Geographical Factors and Land-scape Patterns on Non-point Source Pollution in Watershed Based on Geodetector:Burhatong River Basin,Northeast China as An Example

Changes in natural geographic features and landscape patterns directly influence the hydrology and non-point source pollution processes in the watershed;however,to slow down non-point source pollution,it is necessary to distinguish their effects.But the non-point source pollution process is interactional as a result of multiple factors,and the collinearity between multiple independent variables limits our ability of reason diagnosis.Thus,taking the Burhatong River Basin,Northeast China as an example,the methods of hydrological simulation,geographic detectors,and redundancy analysis have been combined to determine the impact of natural geographic features and landscape patterns on non-point source pollution in the watershed.The Soil&Water Assessment Tool(SWAT)has been adopted to simulate the spatial and temporal distribution characteristics of total nitrogen and total phosphorus in the watershed.The results show that the proportions of agricultural land and forest area and the location-weighted landscape contrast index(LWLI)are the main indicators influencing the rivers total nitrogen and total phosphorus.The interaction of these indicators with natural geographic features and landscape configuration indicators also significantly influences the changes in total nitrogen(TN)and total phosphorus(TP).Natural geographical features and landscape patterns have different comprehensive effects on non-point source pollution in the dry and wet seasons.TN and TP loads are affected mainly by the change in landscape pattern,especially in the wet season.Although the ecological restoration program has improved forest coverage,the purification effect of increased forest coverage on the water quality in the watershed may be offset by the negative impact of increased forest fragmentation.The high concentration and complexity of farmland patches increase the risk of non-point source pollution spread to a certain extent.

基于Geodetector的山区耕地种植生产空间优化--以昭通市为例

为研究面向种植业生产适宜性的区域差异及其定量化评价。针对西南山区种植业生产适宜性的特殊问题,引入了地理探测器空间分析方法科学量化耕地种植生产适宜性评价指标权重,探索了提高山区耕地种植生产适宜性定量评价的科学性和准确性。以云南省昭通市为例,基于地理探测器模型科学量化各评价指标对耕地种植生产适宜性的贡献度,确定了其评价权重,结合加权叠加模型对昭通市山区耕地种植生产适宜性进行了评价,并对山区种植业生产空间进行了优化分析。结果表明:①通过地理探测可以科学定量评价指标对耕地种植生产适宜性的贡献度依次为:积温>年降水量>土壤厚度>坡度>土壤有机质>高程>地形起伏度,且能实现耕地种植生产适宜性准确定量评价;②昭通市现状耕地面积是4651.9 km^(2),耕地种植生产适宜区面积为4550.31 km^(2),通过优化调整后耕地生产空间面积为4741.18 km^(2),既能提出耕地空间分布优化方案,又能有效挖掘耕地生产空间潜力;③昭通市现状耕地中不适宜区主要受生态、坡度、土壤环境容量以及建设占用等因素的影响。研究结果可为山区农业生产合理开发利用和规划管理提供科学支撑。

Application of geodetector in sensitivity analysis of reference crop evapotranspiration spatial changes in Northwest China

Reference crop evapotranspiration(ET0)is an important parameter in the research of farmland irrigation management,crop water demand estimation and water balance in scarce data areas,therefore,it is very important to study the factors affecting the spatial variation of ET0.In this paper,the Penman-Monteith formula was used to calculate ET0 which is the dependent variable of elevation(Elev),daily maximum temperature(T_(max)),daily minimum temperature(Tmin),daily average temperature(T_(mean)),wind speed(U_(2)),sunshine duration(SD)and relative humidity(RH).The sensitivity analysis of ET0 was performed using a Geodetector method based on spatial stratified heterogeneity.The applicability of Geodetector in sensitivity analysis of ET0 was verified by comparing it with existing research results.Results show that RH,Tmax,SD,and Tmean are the main factors affecting ET0 in Northwest China,and RH has the best explanatory power for the spatial distribu‐tion of ET0.Geodetector has a unique advantage in sensitivity analysis,because it can analyze the synergistic effect of two factors on the change of ET0.The interactive detector of Geodetector revealed that the synergistic effect of RH and Tmean on ET0 is very significant,and can explain 89%of the spatial variation of ET0.This research provides a new method for sensitivity analysis of ET0 changes.

Study on the gamma rays and neutrons energy response optimization of a scintillating fiber detector for EAST with Geant4

A new scintillating fiber detector inside magnetic shielding tube was designed and assembled for use in the next round of fusion experiments in the experimental advanced superconducting tokamak to provide D–T neutron yield with time resolution.In this study,Geant4 simulations were used to obtain the pulse height spectra for ideal signals produced when detecting neutrons and gamma rays of multiple energies.One of the main sources of interference was found to be low-energy neutrons below 10–5 MeV,which can generate numerous secondary particles in the detector components,such as the magnetic shielding tube,leading to high-amplitude output signals.To address this issue,a compact thermal neutron shield containing a 1-mm Cd layer outside the magnetic shielding tube and a 5-mm inner Pb layer was specifically designed.Adverse effects on the measurement of fast neutrons and the shielding effect on gamma rays were considered.This can suppress the height of the signals caused by thermal neutrons to a level below the height corresponding to neutrons above 4 MeV because the yield of the latter is used for detector calibration.In addition,the detector has relatively flat sensitivity curves in the fast neutron region,with the intrinsic detection efficiencies(IDEs)of approximately 40%.For gamma rays with energies that are not too high(<8 MeV),the IDEs of the detector are only approximately 20%,whereas for gamma rays below 1 MeV,the response curve cuts off earlier in the low-energy region,which is beneficial for avoiding counting saturation and signal accumulation.

Design of the solar X-ray detector for the Macao Science Satellite-1B

The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection unit and a hard X-ray detection unit.Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators,two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector),and a processing circuit.Compared with similar instruments,the energy range of the SXD is wider(1–600 ke V)and the energy resolution is better(150 e V at 5.9 ke V,12%at 59.5 ke V,and 3%at 662 keV).

Large area^(3)He tube array detector with modular design for multi‑physics instrument at CSNS

The multi-physics instrument(MPI)is the first user cooperative instrument at the China Spallation Neutron Source(CSNS).It was designed to explore the structures of complex materials at multiple scales based on the neutron total scattering technique.This imposes the requirements for the detector,including a high detection efficiency to reduce the measurement time and a large solid angle coverage to cover a wide range of momentum transfers.To satisfy these demands,a large-area array of 3He-filled linear position-sensitive detectors(LPSDs)was constructed,each with a diameter of 1 inch and pressure of 20 atm.It uses an orbicular layout of the detector and an eight-pack module design for the arrangement of 3He LPSDs,covering a range of scattering angles from 3°to 170°with a total detector area of approximately 7 m2.The detector works in air,which is separated from the vacuum environment to facilitate installation and maintenance.The characteristics of the MPI detector were investigated through Monte Carlo(MC)simulations using Geant4 and experimental measurements.The results suggest that the detectors are highly efficient in the wavelength range of the MPI,and an efficiency over 25%is achievable for above 0.1 A neutrons.A minimal position resolution of 6.4 mm full width at half maximum(FWHM)along the tube length was achieved at a working voltage of 2200 V,and a deviation below 2 mm between the real and measured positions was attained in the beam experiment.The detector module exhibited good consistency and an excellent counting rate capacity of up to 80 kHz,which satisfied the requirements of experiments with a high event rate.Observations of its operation over the past year have shown that the detector works steadily in sample experiments,which allows the MPI to serve the user program successfully.

Review: Practical Use of a Neurophysiological Detector and the Protocol for High-Performance Liquid Chromatography

The main aim for discovery and development of the neurophysiological detector was detection of the production’ seats and criminal use of poisons in warfare. Phosphor-organic (PO) substances with acetylcholinesterase-blocking effects are prohibited in warfare by international law (Geneva Protocol. https://www.un.org/disarmament/wmd/bio/1925-geneva-protocol/). Monitoring PO analogs with acetylcholinesterase-blocking effects and their degradation products in water and soil can provide clues to unlawful production sites and the possible use of POs in warfare. Attempts to analyze POs by derivatization have had a low ability to detect them. A neurophysiological detector (NPD)-high-performance liquid chromatography (HPLC) system was developed for specific detection with high detection ability. The first official presentation of our NPD was at the 3rd International Symposium on Separation in BioSciences SBS 2003: A 100 Years of Chromatography, May 13-18, 2003, in Moscow, Russia. The NPD in connection to HPLC was developed 14 years before the presentation at the SBS in 2003. Initially, NPD combined with an HPLC system was developed for intelligence services and only for use in monitoring and espionage against the unlawful production of neuroparalytic agents, as explained in this article. NPD combined with an HPLC system was developed in Umeå, Sweden, in 1987-89;the protocol was further developed in Statens Plantevern Institutt, Ås, Norway, in 1990-92. NPD may have great utility during the current period of active warfare in Europe. The initial challenge was detecting unlawful production and use of PO compounds and their metabolites that can potentially block acetylcholinesterase. The sensor in NPD can detect and monitor substances such as tabun, soman, and modern PO poisons used in military applications. This article describes the history of the development of NPD and its aim as a sensitive sensor in detecting PO substances with acetylcholinesterase-blocking effects.