Unfolding analysis of LaBr3:Ce gamma spectrum with a detector response matrix constructing algorithm based on energy resolution calibration

With respect to the gamma spectrum, the energy resolution improves with increase in energy. The counts of full energy peak change with energy, and this approximately complies with the Gaussian distribution. This study mainly examines a method to deconvolve the LaBr_3:Ce gamma spectrum with a detector response matrix constructing algorithm based on energy resolution calibration.In the algorithm, the full width at half maximum(FWHM)of full energy peak was calculated by the cubic spline interpolation algorithm and calibrated by a square root of a quadratic function that changes with the energy. Additionally, the detector response matrix was constructed to deconvolve the gamma spectrum. Furthermore, an improved SNIP algorithm was proposed to eliminate the background. In the experiment, several independent peaks of ^(152)Eu,^(137)Cs, and ^(60)Co sources were detected by a LaBr_3:Ce scintillator that were selected to calibrate the energy resolution. The Boosted Gold algorithm was applied to deconvolve the gamma spectrum. The results showed that the peak position difference between the experiment and the deconvolution was within ± 2 channels and the relative error of peak area was approximately within 0.96–6.74%. Finally, a ^(133) Ba spectrum was deconvolved to verify the efficiency and accuracy of the algorithm in unfolding the overlapped peaks.

Simulation study of energy resolution with changing pixel size for radon monitor based on Topmetal-Ⅱ^- TPC

In this paper, we study how pixel size influences energy resolution for a proposed pixelated detector—a high sensitivity, low cost, and real-time radon monitor based on a Topmetal-Ⅱ^- time projection chamber(TPC). This monitor was designed to improve spatial resolution for detecting radon alpha particles using Topmetal-Ⅱ^- sensors assembled by a 0.35 lm CMOS integrated circuit process.Owing to concerns that small pixel size might have the side effect of worsening energy resolution due to lower signalto-noise ratio, a Geant4-based simulation was used to investigate the dependence of energy resolution on pixel sizes ranging from 60 to 600 lm. A non-monotonic trend in this region shows the combined effect of pixel size and threshold on pixels, analyzed by introducing an empirical expression. Pixel noise contributes 50 keV full-width at half-maximum energy resolution for 400 lm pixel size at 1–4σ threshold that is comparable to the energy resolution caused by energy fluctuations in the TPC ionization process( ~20 keV). The total energy resolution after combining both factors is estimated to be 54 keV for a pixel size of 400 lm at 1–4σ threshold. The analysis presented in this paper would help choosing suitable pixel size for future pixelated detectors.

Areal density and spatial resolution of high energy electron radiography

Ultrafast imaging tools are of great importance for determining the dynamic density distribution in high energy density(HED)matter.In this work,we designed a high energy electron radiography(HEER)system based on a linear electron accelerator to evaluate its capability for imaging HED matter.40 MeV electron beams were used to image an aluminum target to study the density resolution and spatial resolution of HEER.The results demonstrate a spatial resolution of tens of micrometers.The interaction of the beams with the target and the beam transport of the transmitted electrons are further simulated with EGS5 and PARMELA codes,with the results showing good agreement with the experimental resolution.Furthermore,the experiment can be improved by adding an aperture at the Fourier plane.

Optimal Multi-Timescale Scheduling of Integrated Energy Systems with Hybrid Energy Storage System Based on Lyapunov Optimization

The economic operation of integrated energy system(IES)faces new challenges such as multi-timescale characteristics of heterogeneous energy sources,and cooperative operation of hybrid energy storage system(HESS).To this end,this paper investigates the multi-timescale rolling opti-mization problem for IES integrated with HESS.Firstly,the architecture of IES with HESS is established,a comparative analysis is conducted to evaluate the advantages of the HESS over a single energy storage system(SESS)in stabilizing power fluctuations.Secondly,the dayahead and real-time scheduling cost functions of IES are established,the day-ahead scheduling mainly depends on operation costs of the components in IES,the real-time optimal scheduling adopts the Lya-punov optimization method to schedule the battery and hydrogen energy storage in each time slot,so as to minimize the real-time average scheduling operation cost,and the problem of day-ahead and real-time scheduling error,which caused by the uncertainty of the energy storage is solved by online optimization.Finally,the proposed model is verified to reduce the scheduling operation cost and the dispatching error by performing an arithmetic example analysis of the IES in Shanghai,which provides a reference for the safe and stable operation of the IES.

A high time resolution multi-gap resistive plate chamber

Research on a single cell Multi-gap Resistive Plate Chamber (MRPC) was carried out for the Time Of Flight detector (TOF) R and D of the STAR experi- ment. The property of the single chamber was tested with the test beam facility T10 at CERN in Geneva. The MRPC was scanned with the test beam to get the efficiency and time resolution at different position of the active area. The HV plateau was also measured. The time resolution is 65 ps which satisfies the requirement of STAR. The working mechanism of the MRPC is also explained.

Potential Impact of COP28 Resolution on Taiwan

After two weeks of discussions and consultations at the 28 th Conference of the Parties to the United Nations Framework Convention on Climate Change(COP28),states parties finally reached a series of important sustainable development resolutions and voluntary initiatives.In this paper,the possible impact of these resolutions on Taiwan was mainly discussed,and the relevant regulations and policies that the Taiwan government may enact were analyzed.

Improvement on Gamma Energy Resolution of Plastic Scintillator by Adding PMMA Light Guider or Chamfer

Traditional plastic scintillator has respectively low gamma energy resolution.Space radiation detection need the plastic scintillator to keep a relatively better energy resolution for gamma.Thus we did experiments to study how to get it enhanced by adding light guider and chamfer.A 9000 Bq radioactive source 60 Co has been utilized to make the experiment and results came that when keeping other conditions same,the height of poly methyl methacrylate(PMMA)light guider changes from 12 mm to 40 mm and the energy resolutions varied from 72.3%to63.5% respectively.Furthermore,another contrast experiment was made to decide whether plastic scintillator with light guiders or integrated chamfer can get better energy resolution.In conclusion the plastic scintillator with integrated chamfer got 55.0%.Through the study of adding light guider or chamfer to plastic scintillator,the gamma energy resolution has been improved greatly from 72.3%to 55.0%.

Simulation of a new hybrid MPGD with improved time resolution and decreased discharge probabilities using Garfield＋＋

In this work,a new hybrid MPGD consisting of two GEM foils and a metallic mesh was proposed.Based on the simulation studies,this design can significantly reduce the rise time of signal and has a better performance in respect of particle identification compared with the triple GEM design.The gain with various voltages setting was computed in order to provide us references for future experiment.The simulation results also show that the time and space resolution compared to the triple GEM detector are also improved.The time and space resolution of hybrid detector with Ar/CO_2(70/30) and Ar/isobutane(95/5) were investigated for various drift electric field intensities.This new hybrid detector shows excellent potential for both fundamental research and imaging applications.

Reconstruction of High Resolution Timescale in Weinan Loess Section of Late Quaternary

Seven samples of loess and paleosol collected from the major stratigraphic boundaries of the strata of the Weinan section, Shaanxi Province, are dated using the fine-grained TL technique.Based on the TL results and previously ages-published from this section, the polynomial fitting methods are applied to the development of the high resolution time scale for the Weinan loess section in the late Quaternary. According to this time scale, the ages of S0/L1, L1-1/L1-2, L1-4/L1-5, L1/S1 and S1/L2 stratigraphic boundary of Weinan section are 1. 1, 2. 5, 5. 1,7. 6 and 12. 8 ka B. P., which, with exception of the maximum difference between the ages of L1-4/ L1-5 and the ages of 3/4 stage boundary of the deep-sea oxygen isotopes, are generally consistent with the ages of 1/2, 2/3, 4/5 and 5/6 stage boundary of the deep-sea oxygen isotopes in the SPECMAP curve.

Improvement of energy resolution of x-ray transition-edge sensor using K-means algorithm and Wiener filter

We develop an x-ray Ti/Au transition-edge sensor(TES)with an Au absorber deposited on the center of TES and improved its energy resolution using the K-means clustering algorithm in combination with Wiener filter.We firstly extract the main parameters of each recorded pulse trace,which are adopted to classify these traces into several clusters in the K-means clustering algorithm.Then real traces are selected for energy resolution analysis.Following the baseline correction,the Wiener filter is used to improve the signal-to-noise ratio.Although the silicon underneath the TES has not been etched to reduce the thermal conductance,the energy resolution of the developed x-ray TES is improved from 94 eV to 44 eV at 5.9 keV.

HIGH-RESOLUTION NUMERICAL SIMULATION OF WIND ENERGY RESOURCE IN HAINAN PROVINCE AND ITS OFFSHORE WATERS

With high resolution （1 kin）, the distribution of wind energy resources in Hainan province and over its offshore waters is numerically simulated by using the Wind Energy Simulation Toolkit （WEST） model developed by Meteorological Research Branch of Environment Canada. Compared with observations from eight coastal anemometric towers and 18 existing stations in the province, the simulations show good reproduction of the real distribution of wind resources in Hainan and over its offshore waters, with the relative error of annual mean wind speed being no more than 9% at the 70-m level. Moreover, based on the simulated results of WEST grids that are closest to where the eight wind towers are located, the annual mean wind speeds are further estimated by using the Danish software Wasp （Wind Atlas Analysis and Application Program）. The estimated results are then compared with the observations from the towers. It shows that the relative error is also less than 9%. Therefore, WEST and WEST＋WAsP will be useful tools for the assessment of wind energy resources in high resolution and selection of wind farm sites in Hainan province and over its offshore waters.

Conformal Multi-resolution Time-Domain Method for Scattering Curved Dielectric Objects

A conformal multi-resolution time-domain( CMRTD) method is presented for modeling curved objects. The effective dielectric constant and area weighting are used to derive the update equations of CMRTD. The backward scattering bistatic radar cross sections( RCS) of the dielectric cylinder and ellipsoid are used to validate the proposed method. The results show that the proposed conformal method is more accurate to deal with the complex curved objects in electromagnetic simulations.

Impacts of Increasing Model Resolutions and Shortening Forecast Lead Times on QPFs in South China During the Rainy Season

This study investigated the impacts of increasing model resolutions and shortening forecast lead times on the quantitative precipitation forecast(QPF)for heavy-rainfall events over south China during the rainy seasons in 2013-2020.The control experiment,where the analysis-forecast cycles run with model resolutions of about 3 km,was compared to a lower-resolution experiment with model resolutions of about 9 km,and a longer-term experiment activated 12 hours earlier.Rainfall forecasting in the presummer rainy season was significantly improved by improving model resolutions,with more improvements in cases with stronger synoptic-scale forcings.This is partially attributed to the improved initial conditions(ICs)and subsequent forecasts for low-level jets(LLJs).Forecasts of heavy rainfall induced by landfalling tropical cyclones(TCs)benefited from increasing model resolutions in the first 6 hours.Forecast improvements in rainfall due to shortening forecast lead times were more significant at earlier(1-6 h)and later(7-12 h)lead times for cases with stronger and weaker synoptic-scale forcings,respectively,due to the area-and case-dependent improvements in ICs for nonprecipitation variables.Specifically,significant improvements mainly presented over the northern South China Sea for low-level onshore wind of weak-forcing cases but over south China for LLJs of strong-forcing cases during the presummer rainy season,and over south China for all the nonprecipitation variables above the surface during the TC season.However,some disadvantages of higher-resolution and shorter-term forecasts in QPFs highlight the importance of developing ensemble forecasting with proper IC perturbations,which include the complementary advantages of lower-resolution and longer-term forecasts.

Analysis and optimization of energy resolution of neutron-TPC

Neutron-TPC(n TPC)is a fast neutron spectrometer based on GEM-TPC(Gas Electron Multiplier-Time Projection Chamber)and expected to be used in nuclear physics,nuclear reactor operation monitoring,and thermonuclear fusion plasma diagnostics.By measuring the recoiled proton energy and slopes of the proton tracks,the incident neutron energy can be deduced.It has higher n/γseparation ability and higher detection efficiency than conventional neutron spectrometers.In this paper,neutron energy resolution of n TPC is studied using the analytical method.It is found that the neutron energy resolution is determined by 1)the proton energy resolution(σEp/Ep),and 2)standard deviation of slopes of the proton tracks caused by multiple Coulomb scattering(σk(scattering))and by the track fitting accuracy(σk(fit)).Suggestions are made for optimizing energy resolution of n TPC.Proper choices of the cut parameters of reconstructed proton scattering angles(θcut),the number of fitting track points(N),and the working gas help to improve the neutron energy resolution.

Runge-Kutta Multi-resolution Time-Domain Method for Modeling 3D Dielectric Curved Objects

A conformal Runge-Kutta multi-resolution time-domain(C-RKMRTD)method is present and applied to model and analyze curved objects.Compared with the non-conformal method,the proposed method is more accurate.The scattering analyses of the cylinder and ellipsoid are presented to validate the proposed method.The numerical results demonstrate that the proposed scheme perform better than the MRTD method and other higher order methods with a higher accuracy.

Real-Time Rendering of Dynamic Clouds Using Multi-Resolution Adaptive Grids

The multi-resolution adaptive grids method is proposed to solve the problems of inefficiency in the previous grid-based methods,and it can be used in clouds simulation as well as the interactive simulation between objects and clouds.Oriented bounding box(OBB)hierarchical trees of objects are established,and the resolutions of global and local grids can be selected automatically.The motion equations of fluid dynamics are simplified.Upwind difference is applied to ensure the stability of the simulation process during the discrete process of partial differential equations.To solve the speed problem of existed phase functions,the improved phase function is applied to the illumination calculation of clouds.Experimental results show that the proposed methods can promote the simulation efficiency and meet the need for the simulation of large-scale clouds scene.Real-time rendering of clouds and the interaction between clouds and objects have been realized without preprocessing stage.

Experimental investigation on synergetic prediction of granite rockburst using rock failure time and acoustic emission energy

The frequent occurrence of rockburst and the difficulty in predicting were considered in deep engineering and underground engineering.In this work,laboratory experiments on rockburst under true triaxial conditions were carried out with granite samples.Combined with the deformation characteristics of granite,acoustic emission(AE)technology was well applied in revealing the evolution law of micro-cracks in the process of rockburst.Based on the comprehensive analysis of acoustic emission parameters such as impact,ringing and energy,the phased characteristics of crack propagation and damage evolution in granite were obtained,which were consistent with the stages of rock deformation and failure.Subsequently,based on the critical point theory,the accelerated release characteristics of acoustic emission energy during rockburst were analyzed.Based on the damage theory,the damage evolution model of rock under different loading conditions was proposed,and the prediction interval of rock failure time was ascertained concurrently.Finally,regarding damage as an intermediate variable,the synergetic prediction model of rock failure time was constructed.The feasibility and validity of model were verified.

Readout electronics for a high-resolution soft X-ray spectrometer based on silicon drift detector

The readout electronics for a prototype soft X-ray spectrometer based on silicon drift detector(SDD),for precisely measuring the energy and arrival time of X-ray photons is presented in this paper.The system mainly consists of two parts,i.e.,an analog electronics section(including a pre-amplifier,a signal shaper and filter,a constant fraction timing circuit,and a peak hold circuit)and a digital electronics section(including an ADC and a TDC).Test results with X-ray sources show that an energy dynamic range of 1-10 keV with an integral nonlinearity of less than 0.1%can be achieved,and the energy resolution is better than 160 eV @ 5.9 keV FWHM.Using a waveform generator,test results also indicate that time resolution of the electronics system is about 3.7 ns,which is much less than the transit time spread of SDD(<100 ns)and satisfies the requirements of future applications.

An Approximation to Energy Dissipation in Time Domain Simulation of Sloshing Waves Based on Linear Potential Theory

This paper proposes a new approximation to energy dissipation in time domain simulation of sloshing waves by use of a linear potential theory. The boundary value problem is solved by the NURBS （non-uniform rational B-spline） higher-order panel method, in which a time-domain Green function is employed. The energy dissipation is modeled by changing the boundary condition on solid boundaries. Model experiments are carried out in a partially filled rectangular tank with forced horizontal motion. Sloshing-induced internal pressures and horizontal force obtained numerically and experimentally are compared with each other. It is observed that the present energy dissipation approximation can help produce a fair agreement between experimental forces and those of numerical simulations.

Resolution Enhancement in Ultrasonic TOFD Imaging by Combining Sparse Deconvolution and Synthetic Aperture Focusing Technique(Sparse-SAFT)

The shallow subsurface defects are difficult to be identified and quantified by ultrasonic time-of-flight diffraction(TOFD)due to the low resolution induced by pulse width and beam spreading.In this paper,Sparse-SAFT is proposed to improve the time resolution and lateral resolution in TOFD imaging by combining sparse deconvolution and synthetic aperture focusing technique(SAFT).The mathematical model in the frequency domain is established based on the l1 and l2 norm constraints,and the optimization problem is solved for enhancing time resolution.On this basis,SAFT is employed to improve lateral resolution by delay-and-sum beamforming.The simulated and experimental results indicate that the lateral wave and tip-diffracted waves can be decoupled with Sparse-SAFT.The shallow subsurface defects with a height of 3.0 mm at the depth of 3.0 mm were detected quantitatively,and the relative measurement errors of flaw heights and depths were no more than 10.3%.Compared to conventional SAFT,the time resolution and lateral resolution are enhanced by 72.5 and 56%with Sparse-SAFT,respectively.Finally,the proposed method is also suitable for improving resolution to detect the defects beyond dead zone.