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Studies of an X-ray imaging detector based on THGEM and ccd camera

Radiation Detection Technology and Methods 2018年第1期2卷 178-185页

作者： Zhi-Yuan Peng Yung-Ting Gu Yu-Guang Xie Wen-Qi Yan Hang Zhao Geng-Lan Li Jie-Chen Jiang Huan-Bo Feng Zhi-Gang Wang Jun-Guang Lv Tao Hu Li Zhou Guangxi University Nanning 530004GuangxiChina Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Particle Detection and Electronics Beijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Introduction The photons generated by the electron avalanche in gaseous detectors are known as the secondary scintillation light,of which the spectrum range is from ultraviolet to visible.So it is possible to collect directly the avalanche-induced photons in visible range by light sensors,such as charged-couple device(ccd).The optical readout is a new method for 2-D imaging of high spatial resolution based on the micro-pattern gaseous detectors(MPGDs).Purpose The traditional charge readout method for the MPGDs is complicated,expensive,and strongly depends on the technology of application-specific integrated circuit.In some cases,for example,low-frame-rate 2-D imaging,the optical readout has more advantages,such as simple,cheap and easy to use.Therefore,a gaseous detector was developed based on the thick gaseous electron multiplier(THGEM)and the ordinary scientific ccd camera as readout to realize the X-ray imaging instead of charge readout.Methods and materials The THGEMs with 60×60 mm^(2) sensitive area were developed to reach high gain,and the Ar+CF4 gas mixture was chosen for strong light emission.And so a general scientific ccd can be used for readout and replacing the intensified ccd,which is more expensive than general ccd.Results Some clear X-ray images were obtained by this optical readout THGEM detector,and the spatial resolution achieved is 275µm.It is indicated that this kind of detectors have promising imaging capability and great potential for practical application.

关键词： THGEM ccd camera Optical readout CF4 X-ray imaging

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New measuring method of fiber alignment in precision torsion pendulum experiments

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Chinese Physics B 2020年第8期29卷 162-167页

作者：王冰洁徐利曾维友王晴岚 College of Science Hubei University of Automotive and TechnologyShiyan 442002China

Testing the extreme weak gravitational forces between torsion pendulum and surrounding objects will indicate new physics which attracts many interests.In these measurements,the fiber alignment plays a crucial role in fulfilling high precision placement measurement,especially in measuring the deviation between the fiber and source mass or other objects.The traditional way of the fiber alignment requires to measure the component of the pendulum body and then transfer to the torsion fiber by some complicated calculations.A new method is reported here by using a ccd camera to get the projection image of the torsion fiber,which is a direct and no-contact measurement.Furthermore,the relative position change of the torsion fiber can also be monitored during the experiment.In our experiment,the alignment between the fiber and the center of the turntable has been operated as an example.Our result reaches the accuracy of several micrometers which is higher than the previous method.

关键词： torsion pendulum alignment ccd camera

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Application of ccd cameras to Investigations of Mixing on Boundaries of a Thermal Plasma Jet

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Plasma Science and Technology 2007年第6期9卷 743-746页

作者： J.HLINA J.SONSKY J.SLECHTA Institute of Thermomechanics Academy of Sciences of the Czech RepublicDolejskova 5182 00 Praha 8Czech Republic

Mixing of a thermal plasma jet with the surrounding atmosphere was studied using two ccd cameras （PCO SensiCam） situated detecting simultaneously the radiation of argon and nitrogen. The evaluation of image differences between two records showed that the location of regions on plasma jet boundaries characterised by stronger nitrogen radiation changes with the plasma flow rate. Close-to-laminar flow results in a small mixing rate and consequently low nitrogen optical emission on plasma jet boundaries. The increase of the flow rate leads to the formation of a relatively thick and stable layer on the boundaries characterised by strong nitrogen radiation. Further enhancement of the flow rate results in the formation of unstable regions of excited nitrogen molecules moving along the jet.

关键词： thermal plasma jet mixing ccd camera

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Fuelling and Diagnostics with Pellet Injection in the HL-1M Tokamak

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Plasma Science and Technology 2005年第6期7卷 3085-3091页

作者：彭利林曹建勇李波李立肖正贵郑银甲李承跃崔正英邓柏权严建成袁涛 Southwestern Institute of Physics Chengdu 610041 China

The pellet injection experiments for fuelling and diagnostics have been carried out on the HL-1M tokamak. The eight-pellet injector was installed on HL-1M. A reliable monitordetector and camera system was set up to take initial pellet photographs and measure the initial pellet speed and size. High fuelling efficiency of 60 % - 100 % and a density profile with a peaking factor of 1.8 - 2.0 were obtained. The maximum density close to 10^14/cm^3 in HL-1M was achieved with newly optimized combined fuelling techniques. Two typical models of pellet ablation have been utilized for simulative calculation of the ablation rates in HL-1M. In comparison with the distribution of the measured Hα emission intensity from the digital data of the ccd camera, the experimental result seems more optimistic for core fuelling than theoretical predictions by the two models. The safety factor profile q（r） has been extracted from the information provided by the ccd camera during the pellet injection. The reliability of the measured results depends mainly on the calibration of the imaging space position. Based on the calibration, the measured q-profile becomes more reasonable than those published previously for the same shot number and same photograph.

关键词： pellet injection core fuelling q - profile measurement ccd camera ablation simulation HL-1M tokamak

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Experimental Results from Bore Phenomenon in Open Cylindrical Channel under Precession

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Open Journal of Fluid Dynamics 2022年第1期12卷 69-85页

作者： Hajar Alshoufi Department of Hydraulic and Water Resources Engineering Budapest University of Technology and Economics Budapest Hungary

Experimental campaigns were carried out to extract results from the flow in an open cylindrical channel under precession. The bore or the hydraulic jump is the main concentration. The experimental results are varied;this includes velocity results and geometrical ones related to the depths, phases, and lengths. For the geometrical ones a Coupled-Charged Device camera (ccd) is used to extract pictures, those enable us to get quantitative and qualitative results. For the velocity results, Acoustic Doppler Velocimeter (ADV) is used to extract the velocity signals under the bore surface, after analyzing them it turned out that they have Cnoidal form, thus a new BBM model is derived, which is exactly as the one derived by Peregrine (1966), the only difference is the forcing gravity term, this model is solved analytically after omitting this gravity term as it is considered small, and the solution is compared with the real signals with good match. Finally, a new relationship that connects between the conjugate depths after and before the bore is derived which has time-space dependency due to the Centrifugal effect, it was also used and compared with some experimental results.

关键词： Bore Precession ccd camera ADV Velocimeter Cnoidal Waves

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An Introduction to 2-ccd Digital Particle Image Velocimetry System and Its Application in Ocean Engineering

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China Ocean Engineering 1997年第3期12卷 347-356页

作者： Daichin Timothy P.Dewhirst Ph.D.Candidate State Key Laboratory of Coastal and Offshore EngineeringDalian University of Technology(DUT)Dalian 116023Ph.D.CandidateDepartment of PhysicsUniversity of EdinburghEdinburghUK.

The basic principle of particle image velocinmetry (PIV) is described. When a PIV image is analyzed by the method of auto-correlation, there is a direction ambiguity of 180 degrees iii velocity measurement. The problem can be solved by using 'Image Shifting Technique', but this makes devices much complicated and difficult to control. A new arrangement of 2-ccd (Charge Coupled Device) fully digitized PIV system, which can also solve the problem successfully, is introduced in the paper. As an example of application of the system, an experimental result of flow field around a horizontal cylinder in wave is presented.

关键词： particle image velocimetry ccd camera cross-correlation

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Clastogenic ROS and biophotonics in precancerous diagnosis

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Frontiers in Biology 2018年第2期13卷 103-122页

作者： Muhammad Naveed Mohammad Raees Irfan Liaqat Mohammad Kashif Department of Biotechnology Faculty of Life Sciences University Central Punjab Lahore 54000 Pakistan Department of Biochemistry and Biotechnology University of Gujrat Pakistan 50700 Pakistan

BACKGROUND： Cancer is the leading cause of death worldwide. The application of biophotonics for diagnosing precancerous lesions is a major breakthrough in oncology and is associated with the expression of clastogenic bio-markers, such as reactive oxygen species （ROS）, namely, superoxide anion radicals, hydrogen peroxide, hydroxyl radicals, and lipid peroxidation products. These ROS are the major sources of ultra-weak biophotons emission; in addition, biophotons are emitted from other biomolecules, which are not associated with ROS. The precancerous phase is diagnosed on the basis ofbiophoton emission from biomarkers. The type of biophotons emitted depends on the structure of the clastogenic ROS. METHODS： ROS-based emission of ultra-weak photons can be detected using charge coupled device （ccd） cameras and photomultiplier tubes. Furthermore, spectroscopic and microscopic analysis can yield more advanced and definite results. RESULTS： The frequency and intensity of biophoton emission associated with each ROS provides information regarding the precancerous phase. Previous have attempted to show an association between precancerous growth and biophoton emission; however, their results were not conclusive. In this review, we have addressed multiple aspects of the molecular environment, especially light- matter interactions, to derive a successful theoretical relationship which may have the ability to diaganose the tumor at precancerous stage and to give the solutions of previous failures. This can be a major quantum leap toward precancerous diagnosis therapy. CONCLUSION： Biophotonics provides an advanced framework, for easily diagnosing cancer at its preliminary stage. The relationship between biophotons, clastogenic factors, and biochemical reactions in the cellular microenvironment can be understood successfully. The advancement in precancerous diagnosis will improve human health worldwide. The versatility of biophotonics can be used further for novel applications in biology, biochemistry, chemistry and social fields

关键词： biophotons ccd camera molecular environment oncology precancerous photomultiplier ROS

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Research on Range-gated Laser Active Illuminating Technology

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微计算机信息 2006年第19期 51-53页

作者： (Electric and electronic Engineering College,Changchun University of Technology,Changchun130012,China)Wang,Dongmei (Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130031,China) Wang,Dongmei Zhang,Tao Yan,Feng (Graduate School of Sciences Academy of China,, Beijing 100039) Wang,Dongmei Zhang,Tao Yan,Feng

The laser active illuminated imaging technology utilizes near - infrared laser as illuminated source, the objects are detected and imaging in weak brightness and long range. Synchronism control technology is the crucial technology in range- gated laser active imaging system. In this paper detailed expound on the principle of laser active imaging、laser emission system and receiver technology , at one time expound detailed on range- gated technology , finally analyzed developmental status and foreground in homeland and o- versea about laser active imaging.

关键词： Laser active imaging Range gate ccd camera

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MTF Measurement and Imaging Quality Evaluation of Digital camera with Slanted-edge Method

MTF Measurement and Imaging Quality Evaluation of Digital Ca...

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2010亚洲光电子会议光学设计和检验分会场

作者： ChunChang Xiang a,b,Xinhua Chen a,b,Yuheng Chen a,b,Jiankang Zhou a,b,Weimin Shen a,b(a.Institute of Modern Optical Technology,Soochow University,Suzhou 215006,China b.Jiangsu Key Laboratory of Modern Optical Technology,Suzhou 215006,China)

Modulation Transfer Function（MTF） is the spatial frequency response of imaging systems and now develops as an objective merit performance for evaluating both quality of lens and camera.Slanted-edge method and its principle for measuring MTF of digital camera are introduced in this paper.The setup and software for testing digital camera is respectively established and developed.Measurement results with different tilt angle of the knife edge are compared to discuss the influence of the tilt angle.Also carefully denoise of the knife edge image is performed to decrease the noise sensitivity of knife edge measurement.Comparisons have been made between the testing results gained by slanted-edge method and grating target technique,and their deviation is analyzed.

关键词： Modulation Transfer Function ccd camera grating target method slanted-edge method

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High Precision and Noise Resistance Estimation Based on Optimized GOI Algorithm for Rocket Nozzle

High Precision and Noise Resistance Estimation Based on Opti...

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第37届中国控制会议

作者： Xing Zhou Ju Huo Guiyang Zhang School of Electrical Engineering and Automation Harbin Institute of Technology School of Astronautics Harbin Institute of Technology

This paper is concerned with the rocket nozzle working environment with many interference factors, upon which a high precision and noise resistance algorithm for pose estimation is proposed. The optimized generalized orthogonal iterative（GOI） algorithm is utilized for iterative solution such that it avoids the poor convergence or convergence failure problem caused by the weak perspective projection. The proposed technique only needs to observe the rocket nozzle at different orientations and the objective function based on the collinear error is established, thus the estimated parameters can be obtained subsequently. Finally, simulation and practical experiments are carried out simultaneously. By using the improved algorithm, within a space of 2 m u2 m u4 m, the maximum static error of the swing angles is superior to 0.085 and the maximum dynamic error is less than 0.13°. The results verify the high accuracy and noise resistance performance of the proposed approach.

关键词： Binocular vision ccd camera pose estimation optimized GOI algorithm rocket nozzle

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