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1.
Track segment finding with CGEM-IT and matching to outer drift chamber tracks in the BESIII detector
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Xin-Hua Sun Liang-Liang Wang Ling-Hui Wu Xu-Dong Ju Qing-Lei Xiu Liao-Yuan Dong Ming-Yi Dong Wei-Dong Li Wei-Guo Li Huai-Min Liu Qun Ou-Yang Ye Yuan Yao Zhang 《中国物理C(英文版)》2016,40(9):096203-096203
The relative differences in coordinates of Cylindrical Gas Electron Multiplier Detector-based Inner Tracker(CGEM-IT) clusters are studied to search for track segments in CGEM-IT for the BESIII experiment.With the full simulation of single muon track samples, clear patterns are found and parameterized for the correct cluster combinations. The cluster combinations satisfying the patterns are selected as track segment candidates in CGEM-IT with an efficiency higher than 99%. The parameters of the track segments are obtained by a helix fitting.Some χ~2 quantities, evaluating the differences in track parameters between the track segments in CGEM-IT and the tracks found in the outer drift chamber, are calculated and used to match them. Proper χ~2 requirements are determined as a function of transverse momentum and the matching efficiency is found to be reasonable. 相似文献
2.
ZHANG Yi ZHANG Xiao-Dong WANG Wen-Xin YANG He-Run YANG Zheng-Cai HU Bi-Tao 《中国物理C(英文版)》2009,33(1):42-46
In this paper a two dimensional readout micromegas detector with a polyethylene foil as converter was simulated on GEANT4 toolkit and GARFIELD for fast neutron detection.A new track reconstruction method based on time coincidence technology was developed in the simulation to obtain the incident neutron position.The results showed that with this reconstruction method higher spatial resolution was achieved. 相似文献
3.
YAN Liang HE Kang-Lin LI Wei-Guo BIAN Jian-Ming FU Cheng-Dong HUANG Bin LIU Ying L Qi-Wen NING Fei-Peng SUN Sheng-Sen XU Min ZHANG Jian-Yong ZHU Yong-Sheng 《中国物理C(英文版)》2010,34(2)
In this paper,the kinematic fitting with the Lagrange multiplier method has been studied for BESⅢ experiment.First we introduce the Lagrange multiplier method and implement kinematic constraints.Then we present the performance of the kinematic fitting algorithm.With the kinematic fitting,we can improve the resolution of track parameters and reduce the background. 相似文献
4.
In this paper a two dimensional readout micromegas detector with a polyethylene foil as converter was simulated on GEANT4 toolkit and GARFIELD for fast neutron detection. A new track reconstruction method based on time coincidence technology was developed in the simulation to obtain the incident neutron position. The results showed that with this reconstruction method higher spatial resolution was achieved. 相似文献
5.
In this paper Micromegas has been designed to detect neutrons. The simulation of the spatial reso-lution of Micromegas as neutron detector is carried out by GEANT4 toolkit. The neutron track reconstruction method based on the time coincidence technology is employed in the present work. The influence of the flux of incident 14 MeV neutron and high gamma background on the spatial resolution is carefully studied. Our results show that the spatial resolution of the detector is sensitive to the neutron flux, but insensitive to the intensity of γ background if the neutron track reconstruction method proposed by our group is used. The γ insensitivity makes it possible for us to use the Micromegas detector under condition which has high γ-rays background. 相似文献
6.
YAN Liang HE Kang-Lin LI Wei-Guo BIAN Jian-Ming FU Cheng-Dong HUANG Bin LIU Ying NING Fei-Peng SUN Sheng-Sen XU Min ZHANG Jian-Yong ZHU Yong-Sheng 《中国物理C(英文版)》2010,34(2):204-209
In this paper, the kinematic fitting with the Lagrange multiplier method has been studied for BESⅢ experiment. First we introduce the Lagrange multiplier method and implement kinematic constraints. Then we present the performance of the kinematic fitting algorithm. With the kinematic fitting, we can improve the resolution of track parameters and reduce the background. 相似文献
7.
Ilias Stavrakas Dimos Triantis George Hloupis Konstantinos Moutzouris 《Central European Journal of Physics》2014,12(4):286-291
Specimens of polymer matrix — ceramic TiO2 filler composites were prepared. The contribution of the filler content on the electrical conductivity and energy storage properties of the samples was examined. I–V and Isothermal Polarization/Depolarization Current (IPC/IDC) measurements were conducted. Dc conductivity values directly calculated from the I–V curves exhibited excellent agreement with corresponding values derived from the IPC/IDC recordings. Standard models were employed for fitting the IPC/IDC data. In specific, the short and the very long depolarization times were fitted by use of power laws of different slopes, while the intermediate depolarization times were fitted as a sum of three exponential decays. The present study reveals a strong dependence of the depolarization and polarization processes, as well as of the dc conductivity, on the filler concentration. 相似文献
8.
S. Moretto M. Lunardon A. Dainese A. Jacholkowski A. Rossi 《Indian Journal of Physics》2011,85(6):917-922
Tracking detectors in high-energy physics experiments require an accurate determination of a large number of alignment parameters
in order to allow a precise reconstruction of tracks and vertices. In addition to the initial optical survey, the use of tracks
in a special software alignment is essential. The methods in use for the alignment of the ALICE Inner Tracking System are
presented, starting from residual-based procedure to fitting systems with many thousands of parameters. The two methods are
reviewed and the preliminary results showed. 相似文献
9.
一种简便的计算层析系统X射线硬化校正方法 总被引:1,自引:0,他引:1
以实物拍摄为依据,用一种最简便的修正方法解决计算机X射线层析术成像时由于硬化效应引起的切片图灰度失真问题。用高性能数字X射线机FAXITRON MX-20(射线管焦点20μm,探测板灰度等级16位)对不同厚度的物体进行透射成像,测得对应的透射光强度,并利用新创的指数拟合法得到理想的拟合曲线,由此推导硬化效应的指数校正公式;最后利用实验室的微型计算机层析设备进行扇形束扫描,并逆投影重建生成计算层析断层图像,验证了该校正方法的实用性。该指数拟合法的误差不到常用的二阶多项式拟合法的1/3,对物体计算层析重构,硬化校正以前有明显的“杯状”伪迹,切片灰度不均匀,用指数法修正以后该伪迹消失,切片灰度均匀。 相似文献
10.
CHEN Chao-Qing DENG Yi-Wei LI Ru-Bai LIU Rong-Guang SHI Huan-Zhang WU Jian-Wu 《中国物理C(英文版)》1987,11(5):577-583
It is described that the function,structure, amplitude characteristics and results of cosmic ray test of a prototype of the central drift chamber for Beijing Spectrometer (BES). It was found that if appropriate high voltage is applied on the field wires homogeneous signal amplitude from different Layer of the chamber can be obtained. The drift velocity deduced by track reconstruction is 5.3cm/μs. The spatial resolution is about 134μm. 相似文献
11.
ZHANG Ya-Peng YAO Nan XIAO Zhi-Gang ZHENG Chuan XU Hu-Shan JIN Gen-Ming FAN Rui-Rui FU Fen YUE Se LIANG Jin-Jie CHEN Ruo-Fu SUN Zhi-Yu DUAN Li-Min YUAN Xiao-Hua XU Hua-Gen 《中国物理C(英文版)》2008,32(10)
The necessity of installing a forward tracking detector stack is discussed for the Hadron Physics LanzhoU Spectrometer(HPLUS).A local tracker is developed to solve the multi-track finding problem.The track candidates are searched iteratively via Hough Transform.The fake tracks are removed by a least square fitting process.With this tracker we have studied the feasibility of pp→pp + φ(→K+K-),a typical physical channel proposed on HPLUS.The single track momentum resolution due to the uncertainty of the positioning in FTD is 1.3%.The multiple scattering effect contributes about 20% to the momentum resolution in the FTD coverage.The width and the signal-to-background ratio of the reconstructed φ are 1.51 MeV and 4.36,respectively,taking into account the direct Kaon channel pp→pp+K+K- as background.The geometry coverage of FTD for φ events is about 85.4%.Based on the current fast simulation and estimation,the geometrical configuration of FTD meets the physical requirement of HPLUS under the current luminosity and multiplicity conditions.The tracker is applicable in the full simulation coming next and is extendable to other tracking component of HPLUS. 相似文献
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13.
In this paper Micromegas has been designed to detect neutrons. The simulation of the spatial resolution of Micromegas as neutron detector is carried out by GEANT4 toolkit. The neutron track reconstruction method based on the time coincidence technology is employed in the present work. The influence of the flux of incident 14 MeV neutron and high gamma background on the spatial resolution is carefully studied. Our results show that the spatial resolution of the detector is sensitive to the neutron flux, but insensitive to the intensity of γ background if the neutron track reconstruction method proposed by our group is used. The γ insensitivity makes it possible for us to use the Micromegas detector under condition which has high γ-rays background. 相似文献
14.
Distributed Brillouin fiber sensing based on spectrum line fitting and wavelet packet denoising 总被引:1,自引:0,他引:1
A novel signal processing method is proposed to improve the spatial resolution, frequency resolution and dynamic characteristics of BOTDR. For the BOTDR system with 50 ns pump pulse, by using spectrum line fitting technology based on Levenberg-Marquardt (LM) algorithm, the spatial resolution is improved from 5 m to 5 cm. Combination of LM fitting algorithm, a large frequency scanning interval is adopted without sacrificing measurement accuracy of the BOTDR system. It reduces the number of sampling points of Brillouin spectrum significantly. So, the fitting speed is improved greatly. This is the first time using a large scan interval to increase the spectrum line fitting speed. To improve the fitting speed, the difference between the reference and measured spectrum is used to estimate the variation of Brillouin frequency shift. The measured amplitude of Brillouin spectrum is used to estimate the width of region strain occurred. Finally, by using wavelet packet denoising technology, the spectra containing noise are fitted successfully. 相似文献
15.
Matrix inversion and least squares fitting have been used to recover two dimensional distribution functions from a small number of line integrals taken along chords across them. A self-consistent optimization procedure, free from reliance on comparison with a trial source function, for optimizing the configuration of these chords is described and used to demonstrate that an asymmetric arrangement usually leads to greater reconstruction accuracy than a regular array. Smoothing is incorporated by imposing auxiliary conditions relating to the second derivative ?2f of the source function f, and its effect on reconstruction accuracy and resolution is investigated. These methods are applied to the ten-channel far-infrared interferometer being prepared for use on JET. Electron denisty contour shapes can be identified rather sensitively if the source function contours belong to a predetermined family. 相似文献
16.
Muon tomography is a promising method in the detection and imaging of high Z material. In general, considering the quality of track reconstruction in imaging, a detector of good position resolution, high efficiency and large area is required. This paper presents the design and study of a prototype of position sensitive MRPC with 0.15 mm narrow gas gap and 2.54 mm strip readout. Through a cosmic-ray experiment, the performance of MRPC module is carefully observed and each channel is calibrated. Through an X ray experiment with a narrow slit, the position resolution is studied. The results show that the time resolution of the module can reach 61ps and the spatial resolution can reach 0.36 mm. 相似文献
17.
《中国物理C(英文版)》2017,(8)
We have studied optimization of the design of a barrel-shaped pixelated tracker for given spatial boundaries. The optimization includes choice of number of layers and layer spacing. Focusing on tracking performance only,momentum resolution is chosen as the figure of merit. The layer spacing is studied based on Gluckstern's method and a numerical geometry scan of all possible tracker layouts. A formula to give the optimal geometry for curvature measurement is derived in the case of negligible multiple scattering to deal with trajectories of very high momentum particles. The result is validated by a numerical scan method, which could also be implemented with any track fitting algorithm involving material effects, to search for the optimal layer spacing and to determine the total number of layers for the momentum range of interest under the same magnetic field. The geometry optimization of an inner silicon pixel tracker proposed for BESIII is also studied by using a numerical scan and these results are compared with Geant4-based simulations. 相似文献
18.
19.
Ahmad R Clymer B Vikram DS Deng Y Hirata H Zweier JL Kuppusamy P 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2007,184(2):246-257
The broad spectrum of spin probes used for electron paramagnetic resonance imaging (EPRI) result in poor spatial resolution of the reconstructed images. Conventional deconvolution procedures can enhance the resolution to some extent but obtaining high resolution EPR images is still a challenge. In this work, we have implemented and analyzed the performance of a postacquisition deblurring technique to enhance the spatial resolution of the EPR images. The technique consists of two steps; noniterative deconvolution followed by iterative deconvolution of the acquired projections which are then projected back using filtered backprojection (FBP) to reconstruct a high resolution image. Further, we have proposed an analogous technique for iterative reconstruction algorithms such as multiplicative simultaneous iterative reconstruction technique (MSIRT) which can be a method of choice for many applications. The performance of the suggested deblurring approach is evaluated using computer simulations and EPRI experiments. Results suggest that the proposed procedure is superior to the standard FBP and standard iterative reconstruction algorithms in terms of mean-square-error (MSE), spatial resolution, and visual judgment. Although the procedure is described for 2D imaging, it can be readily extended to 3D imaging. 相似文献