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Reduce the effects of Fabry-Perot interference and system dispersion in continuous wave terahertz coherence measurements with two optical-path differences

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OPTICS AND LASERS IN ENGINEERING 2020年 134卷 106234-106234页

作者： Lin, Qi Lin, Zhongxi Li, Yong Su, Hui Ma, Fusheng Chinese Acad Sci Fujian Inst Res Struct Matter 155 Yangqiao Rd West Fuzhou 350002 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Nanjing Normal Univ Ctr Quantum Transport & Thermal Energy Sci Sch Phys & Technol Jiangsu Key Lab Optoelect Technol Nanjing 210023 Peoples R China

For terahertz frequency domain spectrometers (THz-FDS), the effects of Fabry-Perot (FP) interference and system dispersion are inevitable, thus the typical data-analysis methods normally result in large errors in the measurement of the THz transmission spectrum and refractive index of samples. By using the phase relationship between two groups of acquired THz-FDS data with different optical paths, we present a new method to eliminate the system dispersion and reduce the impact of FP interference on the refractive index measurement with a relative error decreased from 6.8% to 2.5%.

关键词： THz-FDS data processing methods Fabry-Perot interference System dispersion Refractive index Transmission spectrum

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An improved path-tracking controller with mid-angle adaptive calibration for combine harvester

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JOURNAL OF INSTRUMENTATION 2020年第1期15卷

作者： Qiao, N. Wang, L. Zhu, W. Tang, X. Jin, C. Yaoming, L. Xu, L. Southeast Univ Key Lab Microinertial Instrument & Adv Nav Techno Sch Instrument Sci & Engn Minist Educ Nanjing 210096 Peoples R China Jiangsu Univ Key Lab Modern Agr Equipment & Technol Minist Educ Zhenjiang 212013 Jiangsu Peoples R China

The assisted driving system of combine harvester with the mid-angle error carries the path-tracking deviation and limits the harvesting efficiency. In the manual calibration method, the accuracy and convenience of mid-angle calibration are limited by the unreliable driving skills. This paper analyzes the trajectory of harvester and builds the error model of mid-angle. An improved path-tracking controller with mid-angle adaptive calibration is proposed. The new controller calculates the average lateral errors of harvester through an interval window adjusted by fuzzy controller. The mid-angle is calibrated and the path-tracking deviation is restrained by the increment PID model. To improve the calibration accuracy and convergence speed, the PID parameters are optimized by particle swarm optimization (PSO). However, the inertia weight of adaptive inertia weight PSO decreases too fast in path-tracking system, a high-order system. The improved PSO, proposed in this paper, combines the iteration number and feedback function as the inertia weight strategy and adapts inertia weight. The experiments demonstrate that the new controller can restrain the path-tracking deviation from 17.02 cm to -0.73 cm and improve the accuracy of harvesting.

关键词： data processing methods Pattern recognition cluster finding calibration and fitting methods

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Image processing for X-ray transmission radiography with 3D voxel detector

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JOURNAL OF INSTRUMENTATION 2011年第12期6卷 C12061-C12061页

作者： Jandejsek, I. Soukup, P. Jakubek, J. Czech Tech Univ Inst Expt & Appl Phys CZ-12800 Prague 2 Czech Republic

Presented paper deals with the image processing for the new 3D voxel detector. The detector is mainly intended for particle tracking applications, but it has also advantages in conventional X-ray transmission radiography. Imaging with such device brings benefits such as higher detection efficiency, presence of directional information and mapping of beam-hardening effects. To get these additional imaging possibilities, the raw image data acquired by the voxel detector have to be processed by a method of image matching based on the Lucas-Kanade algorithm in conjunction with a cross-correlation method. The main result of the image data processing is an assembled image ready for further analysis. The secondary outcome is the information about the geometry of the imaging setup (i.e. measured position of the detector relative to the X-ray source). Results together with evaluation of the techniques are demonstrated on images of real samples.

关键词： Image filtering data processing methods Image reconstruction in medical imaging Pattern recognition, cluster finding, calibration and fitting methods

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Development of Adaptive Variable Boundary based Real Coded Genetic Algorithm for online optimization of beam excitation level for Indus-2 tune measurement system

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JOURNAL OF INSTRUMENTATION 2018年第7期13卷 P07028-1-P07028-13页

作者： Yadav, S. Puntambekar, T. A. Varde, P. V. Raja Ramanna Ctr Adv Technol Indore Madhya Pradesh India Homi Bhabha Natl Inst Training Sch Complex Bombay Maharashtra India Bhabha Atom Res Ctr Bombay Maharashtra India

Indus-2 is a synchrotron radiation source which is operational at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India. The betatron tune measurement system is an essential beam diagnostic system for smooth beam operation of Indus-2 which is based on swept frequency excitation method. In this method, a lookup table is used for adjustment of excitation signal level in the drive system and selection of reciver parameters such as sweep rate and bandwidth. It is observed that, beam excitation levels are required to be calibrated regularly due to change in the operating parameters of Indus-2. To cater this problem of re-calibration, a new tune measurement system for Indus-2 is developed based on optimal control method using genetic algorithm. Multiple parameters and multi-objective control were required to develop this system. A variant of genetic algorithm (GA) is developed for online control of this system. In this algorithm, real valued variables are used and their boundaries are adaptively modified during the online optimization, hence this variant of GA is called as Adaptive Variable Boundary based Real Coded Genetic Algorithm (AVB-RCGA). This system provides comparatively better results as compared to the old tune measurement system. The new tune measurement system is faster with better signal to noise ratio (SNR) for entire range of machine operation.

关键词： Beam-line instrumentation (beam position and profile monitors beam-intensity monitors bunch length monitors) Instrumentation for synchrotron radiation accelerators Accelerator Subsystems and Technologies data processing methods

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A density-based clustering algorithm for the CYGNO data analysis

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JOURNAL OF INSTRUMENTATION 2020年第12期15卷

作者： Baracchini, E. Benussi, L. Bianco, S. Capoccia, C. Caponero, M. Cavoto, G. Cortez, A. Costa, I. A. Di Marco, E. D'Imperio, G. Dho, G. Lacoangeli, F. Maccarrone, G. Marafini, M. Mazzitelli, G. Messina, A. Nobrega, R. A. Orlandi, A. Paoletti, E. Passamonti, L. Petrucci, F. Piccolo, D. Pierluigi, D. Pinci, D. Renga, F. Rosatelli, F. Russo, A. Saviano, G. Tesauroc, R. Tomassini, S. Gran Sasso Sci Inst I-67100 Laquila Italy Ist Nazl Fis Nucl Lab Nazl Gran Sasso Assergi Italy Ist Nazl Fis Nucl Lab Nazl Frascati I-00044 Frascati Italy ENEA Ctr Ric Frascati Frascati Italy Ist Nazl Fis Nucl Sez Roma I-00185 Rome Italy Sapienza Univ Roma Dipartimento Fis I-00185 Rome Italy Univ Fed Juiz de Fora Juiz De Fora Brazil Museo Stor Fis Piazza Viminale 1 I-00184 Rome Italy Ctr Studi & Ric Enrico Fermi Piazza Viminale 1 I-00184 Rome Italy Univ Roma TRE Dipartimento Matemat & Fis Rome Italy Ist Nazl Fis Nucl Sez Roma TRE Rome Italy Sapienza Univ Roma Dipartimento Ingn Chim Mat & Ambiente Rome Italy

Time Projection Chambers (TPCs) working in combination with Gas Electron Multipliers (GEMS) produce a very sensitive detector capable of observing low energy events. This is achieved by capturing photons generated during the GEM electron multiplication process by means of a high-resolution camera. The CYGNO experiment has recently developed a TPC Triple GEM detector coupled to a low noise and high spatial resolution CMOS sensor. For the image analysis, an algorithm based on an adapted version of the well-known DBSCAN was implemented, called iDBSCAN. In this paper a description of the iDBSCAN algorithm is given, including test and validation of its parameters, and a comparison with DBSCAN itself and a widely used algorithm known as Nearest Neighbor Clustering (NNC). The results show that the adapted version of DBSCAN is capable of providing full signal detection efficiency and very good energy resolution while improving the detector background rejection.

关键词： data processing methods Image filtering Micropattern gaseous detectors (MSGC, GEM, THGEM, RETHGEM, MHSP, MICROPIC, MICROMEGAS, InGrid, etc) Pattern recognition cluster finding calibration and fitting methods

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Beam diagnostics with silicon pixel detector array at PADME experiment

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JOURNAL OF INSTRUMENTATION 2024年第1期19卷 C01016页

作者： Bertelli, S. Bossi, F. Di Giulio, C. Di Meco, E. Dimitrova, K. De Sangro, R. Domenici, D. Frankenthal, A. Ferrarotto, F. Finocchiaro, G. Foggetta, L. G. Garattini, M. Georgiev, G. Gianotti, P. Ivanov, S. Ivanov, Sv. Kozhuharov, V. Leonardi, E. Long, E. Mancini, M. Oceano, I. Oliva, F. Organtini, G. C. Piperno, G. Raggi, M. Sarra, I. Simeonov, R. Spadaro, T. Spiriti, E. Taruggi, C. Vilucchi, E. Valente, P. Variola, A. Sofia Univ 5 J Bourchier Str Sofia Bulgaria INFN LNF Via E Fermi 54 Frascati Italy INFN Sez Roma Rome Italy Sapienza Univ Rome Italy Princeton Univ Princeton NJ USA DESY Hamburg Germany Edingburgh Univ Edingburgh Scotland

During 2022 data taking (Run III) PADME searched for a resonant production and a visible decay of the X17 particle into e(+)e(-). A precise knowledge within 1% uncertainty of the number of positrons was required for the observation. To that purpose, an array of 2 x 6 Timepix3 (total of 512 x 1536 pixels) hybrid pixel detectors operated in data-streaming mode with ToA resolution of 1.56 ns for every pixel was employed. Two methods for data acquisition were developed. A frame-based method, integrating the number of hits for each individual pixel for a predefined period of time served for monitoring the beam conditions and to provide a rough estimation of the beam distribution and number of positrons. A data streaming mode exploiting the nanosecond time resolution of Timepix3 detector was used for precise characterization of the transverse beam profile and the distribution of the incident positrons within each bunch of similar to 200 ns duration.

关键词： Beam-line instrumentation (beam position and profile monitors beam-intensity monitors bunch length monitors) Particle tracking detectors Analysis and statistical methods data processing methods

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Quantitative proton magnetic resonance spectroscopy without water suppression

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JOURNAL OF INSTRUMENTATION 2009年第06期4卷 P06014-P06014页

作者： Ozdemir, M. S. De Deene, Y. Fieremans, E. Lemahieu, I. Univ Ghent IBBT IBiTech MEDISIP Dept Elect & Informat Syst B-9000 Ghent Belgium Ghent Univ Hosp Dept Radiotherapy B-9000 Ghent Belgium

The suppression of the abundant water signal has been traditionally employed to decrease the dynamic range of the NMR signal in proton MRS ((1)H MRS) in vivo. When using this approach, if the intent is to utilize the water signal as an internal reference for the absolute quantification of metabolites, additional measurements are required for the acquisition of the water signal. This can be prohibitively time-consuming and is not desired clinically. Additionally, traditional water suppression can lead to metabolite alterations. This can be overcome by performing quantitative 1H MRS without water suppression. However, the non-water-suppressed spectra suffer from gradient-induced frequency modulations, resulting in sidebands in the spectrum. Sidebands may overlap with the metabolites, which renders the spectral analysis and quantification problematic. In this paper, we performed absolute quantification of metabolites without water suppression. Sidebands were removed by utilizing the phase of an external reference signal of single resonance to observe the time-varying the static field fluctuations induced by gradient-vibration and deconvolving this phase contamination from the desired NMR signal. The quantification of metabolites was determined after sideband correction by calibrating the metabolite signal intensities against the recorded water signal. The method was evaluated by phantom and in vivo measurements in human brain. The maximum systematic error for the quantified metabolite concentrations was found to be 10.8%, showing the feasibility of the quantification after sideband correction.

关键词： data processing methods Simulation methods and programs MRI (whole body, cardiovascular, breast, others), MR-angiography (MRA) Medical-image reconstruction methods and algorithms, computer-aided so

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Exploiting unsupervised and supervised classification for segmentation of the pathological lung in CT

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JOURNAL OF INSTRUMENTATION 2009年第7期4卷 P07013-P07013页

作者： Korfiatis, P. Kalogeropoulou, C. Daoussis, D. Petsas, T. Adonopoulos, A. Costaridou, L. Univ Patras Sch Med Dept Med Phys Patras 26500 Greece Univ Hosp Patras Dept Radiol Patras 26500 Greece Univ Hosp Patras Dept Rheumatol Patras 26500 Greece

Delineation of lung fields in presence of diffuse lung diseases (DLPDs), such as interstitial pneumonias (IP), challenges segmentation algorithms. To deal with IP patterns affecting the lung border an automated image texture classification scheme is proposed. The proposed segmentation scheme is based on supervised texture classification between lung tissue ( normal and abnormal) and surrounding tissue ( pleura and thoracic wall) in the lung border region. This region is coarsely defined around an initial estimate of lung border, provided by means of Markov Radom Field modeling and morphological operations. Subsequently, a support vector machine classifier was trained to distinguish between the above two classes of tissue, using textural feature of gray scale and wavelet domains. 17 patients diagnosed with IP, secondary to connective tissue diseases were examined. Segmentation performance in terms of overlap was 0.924 +/- 0.021, and for shape differentiation mean, rms and maximum distance were 1.663 +/- 0.816, 2.334 +/- 1.574 and 8.0515 +/- 6.549 mm, respectively. An accurate, automated scheme is proposed for segmenting abnormal lung fields in HRC affected by IP

关键词： data processing methods Pattern recognition, cluster finding, calibration and fitting methods Computerized Tomography (CT) and Computed Radiography (CR)

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The ALICE experiment at the CERN LHC

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JOURNAL OF INSTRUMENTATION 2008年第08期3卷 S08002-S08002页

作者： Aamodt, K. Quintana, A. Abrahantes Achenbach, R. Acounis, S. Adamova, D. Adler, C. Aggarwal, M. Agnese, F. Rinella, G. Aglieri Ahammed, Z. Ahmad, A. Ahmad, N. Ahmad, S. Akindinov, A. Akishin, P. Aleksandrov, D. Alessandro, B. Alfaro, R. Alfarone, G. Alici, A. Alme, J. Alt, T. Altinpinar, S. Amend, W. Andrei, C. Andres, Y. Andronic, A. Anelli, G. Anfreville, M. Angelov, V. Anzo, A. Anson, C. Anticic, T. Antonenko, V. Antonczyk, D. Antinori, F. Antinori, S. Antonioli, P. Aphecetche, L. Appelshaeuser, H. Aprodu, V. Arba, M. Arcelli, S. Argentieri, A. Armesto, N. Arnaldi, R. Arefiev, A. Arsene, I. Asryan, A. Augustinus, A. Awes, T. C. Aeysto, J. Azmi, M. Danish Bablock, S. Badala, A. Badyal, S. K. Baechler, J. Bagnasco, S. Bailhache, R. Bala, R. Baldisseri, A. Baldit, A. Ban, J. Barbera, R. Barberis, P. -L. Barbet, J. M. Barnaefoldi, G. Barret, V. Bartke, J. Bartos, D. Basile, M. Basmanov, V. Bastid, N. Batigne, G. Batyunya, B. Baudot, J. Baumann, C. Bearden, I. Becker, B. Belikov, J. Bellwied, R. Belmont-Moreno, E. Belogianni, A. Belyaev, S. Benato, A. Beney, J. L. Benhabib, L. Benotto, F. Beoe, S. Berceanu, I. Bercuci, A. Berdermann, E. Berdnikov, Y. Bernard, C. Berny, R. Berst, J. D. Bertelsen, H. Betev, L. Bhasin, A. Baskar, P. Bhati, A. Bianchi, N. Bielcik, J. Bielcikova, J. Bimbot, L. Blanchard, G. Blanco, F. Blanco, F. Blau, D. Blume, C. Blyth, S. Boccioli, M. Bogdanov, A. Boggild, H. Bogolyubsky, M. Boldizsar, L. Bombara, M. Bombonati, C. Bondila, M. Bonnet, D. Bonvicini, V. Borel, H. Borotto, F. Borshchov, V. Bortoli, Y. Borysov, O. Bose, S. Bosisio, L. Botje, M. Boettger, S. Bourdaud, G. Bourrion, O. Bouvier, S. Braem, A. Braun, M. Braun-Munzinger, P. Bravina, L. Bregant, M. Bruckner, G. Brun, R. Bruna, E. Brunasso, O. Bruno, G. E. Bucher, D. Budilov, V. Budnikov, D. Buesching, H. Buncic, P. Burns, M. Burachas, S. Busch, O. Bushop, J. Cai, X. Caines, H. Calaon, F. Caldogno, M. Cali, I. Camerini, P. Campagnolo, R. Campbell, M. Cao, X. Capitani, G. P. Romeo, G. Cara Cardenas-Montes, M. Carduner, H. Carena, F. Lund Univ Div Expt High Energy Phys Lund Sweden Univ Oslo Dept Phys Oslo Norway Ctr Aplicac Tecnol & Desarrollo Nucl CEADEN Madrid Spain Ctr Aplicac Tecnol & Desarrollo Nucl CEADEN Havana Cuba Heidelberg Univ Kirchhoff Inst Phys Heidelberg Germany Univ Nantes CNRS IN2P3 Ecol Mines NantesSUBATECH Nantes France Acad Sci Czech Republ Inst Nucl Phys CZ-25068 Rez Czech Republic Heidelberg Univ Inst Phys D-6900 Heidelberg Germany Panjab Univ Dept Phys Chandigarh 160014 India Univ Strasbourg CNRS IN2P3 IPHC Strasbourg France CERN European Org Nucl Res CH-1211 Geneva Switzerland Ctr Variable Energy Cyclotron Kolkata India Aligarh Muslim Univ Dept Phys Aligarh 202002 Uttar Pradesh India Inst Theoret & Expt Phys Moscow 117259 Russia Joint Inst Nucl Res Dubna Russia Russian Res Ctr Kurchatov Inst Moscow Russia Sezione Ist Nazl Fis Nucl Turin Italy Univ Nacl Autonoma Mexico Inst Fis Mexico City 01000 DF Mexico Univ Bologna Dipartimento Fis Bologna Italy Sezione Ist Nazl Fis Nucl Bologna Italy Univ Bergen Dept Phys Bergen Norway Gesell Schwerionenforsch mbH GSI D-6100 Darmstadt Germany Goethe Univ Frankfurt Inst Kernphys D-6000 Frankfurt Germany Natl Inst Phys & Nucl Engn Bucharest Romania CEA DAPNIA Ctr Etudes Nucl Saclay France Creighton Univ Omaha NE 68178 USA Rudjer Boskovic Inst Zagreb Croatia Sezione Ist Nazl Fis Nucl Padua Italy Sezione Ist Nazl Fis Nucl Cagliari Italy Politecn & Sez INFN Bari Italy Univ Santiago de Compostela IGFAE Santiago De Compostela Spain St Petersburg State Univ V Fock Inst Phys St Petersburg Russia Oak Ridge Natl Lab Oak Ridge TN USA Univ Jyvaskyla Helsinki Finland Sezione Ist Nazl Fis Nucl Catania Italy Univ Jammu Dept Phys Jammu 180004 India Univ Blaise Pascal CNRS IN2P3 LPC Clermont Ferrand France Slovak Acad Sci Inst Expt Phys Kosice 04353 Slovakia Safarik Univ Fac Sci Kosice Slovakia Univ Catania Dipartmento Fis Catania Italy Hungarian Acad Sci KFKI Res Inst Particle & Nucl Ph

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This pap

关键词： Instrumentation for heavy-ion accelerators Instrumentation for particle accelerators and storage rings - high energy Cherenkov and transition radiation Gaseous detectors Liquid detectors Photon detectors for UV, visible and IR photons Scintillators, scintillation and light emission processes Solid state detectors Calorimeters Cherenkov detectors dE/dx detectors Gamma detectors Large detector systems for particle and astroparticle physics Particle identification methods Particle tracking detectors Photon detectors for UV, visible and IR photons Spectrometers Time projection chambers Timing detectors Transition radiation detectors Analysis and statistical methods Computing data processing methods data reduction methods Pattern recognition, cluster finding, calibration and fitting methods Simulation methods and programs Software architectures Detector alignment and calibration methods Detector cooling and thermo-stabilization Detector design and construction technologies and materials Detector grounding Manufacturing Overall mechanics design Special cables Voltage distributions

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Searching for a particle of unknown mass and lifetime in the presence of an unknown non-monotonic background

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JOURNAL OF INSTRUMENTATION 2015年第6期10卷 2015 JINST 10 P06002-2015 JINST 10 P06002页

作者： Williams, M. MIT Nucl Sci Lab Cambridge MA 02139 USA

Many extensions to the Standard Model of particle physics hypothesize the existence of new low-mass particles. Typically there are few theoretical constraints on the mass or lifetime of such particles. This requires the experimentalist to perform a search in which both the mass and lifetime of the particle are unknown. Such searches for low-mass particles are complicated by the possible presence of resonances and other non-monotonic backgrounds. This paper presents a simple and fast approach to assigning significance and setting limits in such searches.

关键词： Analysis and statistical methods data processing methods

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