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Development of high-performance multichannel analyzer by using traditional pulse forming method and high-speed waveform sampling technology

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JOURNAL OF INSTRUMENTATION 2019年第5期14卷 T05003-T05003页

作者： Li, Gang Wan, Bo Li, Kun Chen, Zhi Han, Yu Yang, Daibo Zeng, Shaoli Nucl Power Inst China Sci & Technol Reactor Syst Design Technol Lab Chengdu 610213 Sichuan Peoples R China

A high performance multichannel analyzer (MCA) based on traditional used pulse forming method and high-speed waveform sampling technology was developed in this paper for spectra analysis and radioactive measurement. The self-developed MCA is composed of conditioning part and processing part. The conditioning part including pole-zero cancellation, polarity conversion, programmable amplification, active integral filter, baseline recovery and peak holding is adopted to realize amplification, Gauss shaping and peak holding functions, while the processing part mainly including dither circuit, 16-bit 100 MHz high speed ADC and FPGA is employed to make waveform sampling and spectra acquisition. The performance including the differential nonlinearity (DNL), integral nonlinearity (INL) and energy resolution are studied by using precision sliding pulse generator, NaI scintillator detector and radiation sources. The results show that the DNL and INL of the MCA are better than 1.06% and 0.09% respectively, and the energy resolution measured with NaI scintillator detector at 0.662 MeV is about 7.82%. In addition, the DNL value depends on the appropriate selection of dither channels, and the optimal dither channel is 64 for the self-developed MCA in this paper. At last, the overall performance of the self-developed MCA is compared with a commercially available NIM plug-in type MCA, the results indicate that the MCA designed in this paper is obviously better than the commercially available MCA.

关键词： Control and monitor systems online data processing methods Radiation monitoring Spectrometers

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Dual-energy materials characterization methods for laminography image enhancement based on photon counting detector

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JOURNAL OF INSTRUMENTATION 2019年第2期14卷 P02018-P02018页

作者： Ou, D. Schumacher, D. Zscherpel, U. Xiao, Y. Tsinghua Univ Dept Engn Phys Beijing 100084 Peoples R China Tsinghua Univ Minist Educ Key Lab Particle & Radiat Imaging Beijing Peoples R China Bundesanstalt Mat Forsch & Prufung BAM Berlin Germany

Laminography is a widely used NDT technique for large flat object which cannot be investigated by traditional computed tomography. However, due to the limited scanning angle of laminography, the reconstructed image has more artifact interference, which seriously affects the reconstructed image quality. Reducing artifacts of the laminography image and enhancing the images have become important research effort. In this paper, we present dual-energy materials characterization methods based on photon counting detectors to reduce artifacts and enhance image for laminography. The photon counting detector used in this study allows the setting of two independent energy thresholds in order to acquire dual-energy images for laminography from a single scan. The dual energy imaging methods of basis material decomposition (BMD) and weighted logarithmic subtraction (WLS) were studied in the paper with respect to laminography image enhancement. A fast decomposition algorithm on laminographic projection domain with approximating the inverse dual-energy equations to calculate the thickness of basic materials was used in the BMD dual-energy imaging methods. The experimental results show that the BMD method can characterize materials and enhance features of the basic material within the laminographic dataset. In the WLS method, a linear operation was applied on dual-energy images reconstruction directly, which can eliminate the attenuation of one specific material in the resultant image by setting an appropriate weighting factor. In our experiments. WLS method was used successfully to eliminate the strong artifacts generated by the special material and enhance the images. Dual-energy materials characterization methods based on photon counting detectors show potential applications in laminography.

关键词： data processing methods Inspection with x-rays X-ray detectors

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Refining scan positions in Ptychography through error minimisation and potential application of Machine Learning

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JOURNAL OF INSTRUMENTATION 2018年第6期13卷 C06002-C06002页

作者： Guzzi, F. Kourousias, G. Bille, F. Pugliese, R. Reis, C. Gianoncelli, A. Carrato, S. Univ Trieste Dept Engn & Architecture DIA Via A Valerio 10 I-34127 Trieste Italy Elettra Sincrotrone Trieste SCpA Str Statale 14AREA Sci Pk I-34149 Trieste Italy

Ptychography is an advanced technique whose latest developments have allowed for exceptionally high resolution in X-ray microscopy, as well as new setups that can even be lensless;the spatial resolution has already reached <5 nm in synchrotron beamlines. Still there are certain demanding requirements such as beam coherence and strong involvement of computational methods that make it a rather difficult technique to implement. In this paper we introduce a computational work-flow aiming at refining the individual probe positions of a ptychography scan. Indeed, the precision of those positions is of high importance as it impacts the reconstruction. Special setups using precise sample stages with nanopositioning and advanced interferometers are important;however, positioning errors still remain a problem for many operating laboratories. This paper examines the Structural Similarity Index as a suitable metric for evaluating the registration in alignment of individually reconstructed probes. Eventually it suggests the use of Machine Learning techniques as future direction in probe alignment. It also presents a new software tool for precise manual alignment and visualization. All the software developed during this research project is provided to the scientific community as open source.

关键词： data processing methods Analysis and statistical methods

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PymePix: a python library for SPIDR readout of Timepix3

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JOURNAL OF INSTRUMENTATION 2019年第10期14卷 P10003-P10003页

作者： Al-Refaie, A. F. Johny, M. Correa, J. Pennicard, D. Svihra, P. Nomerotski, A. Trippel, S. Kuepper, J. Deutsch Elektronen Synchrotron DESY Ctr Free Electron Laser Sci Notkestr 85 D-22607 Hamburg Germany Univ Hamburg Dept Phys Luruper Chaussee 149 D-22761 Hamburg Germany Deutsch Elektronen Synchrotron DESY Notkestr 85 D-22607 Hamburg Germany Czech Tech Univ Fac Nucl Sci & Phys Engn Dept Phys Brehova 78-7 Prague 11519 Czech Republic Univ Manchester Sch Nat Sci Dept Phys & Astron Brunswick St Manchester M13 9PL Lancs England Brookhaven Natl Lab Cosmol & Astrophys Grp Upton NY 11973 USA Univ Hamburg Ctr Ultrafast Imaging Luruper Chaussee 149 D-22761 Hamburg Germany

PymePix is a new Python 3 library that provides control and acquisition for the Timepix3-SPIDR hardware. The rich set of data-structures and intuitive routines reduces time and coding effort to quickly configure, acquire, and visualize data from Timepix3. The highly extensible high-performance data-pipeline allows for alteration of the Timepix3 datastream into a form that is convinient for the user. This library is intended to be easily inserted into a standard scientific software stack as well as to allow for more direct interaction of Timepix3 with interactive flavors of Python. Included with the library are two example programs using PymePix: pymepix-acq is a command line control and acquisition program that can capture UDP packets and decode them into pixels and triggers. The second is pymepixviewer, an online control and data-acquisition program for general use, but with features geared toward mass-spectroscopy and ion imaging.

关键词： data processing methods Instrumentation and methods for time-of-flight (TOF) spectroscopy Software architectures (event data models, frameworks and databases) Timing detectors

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Improving the spatial resolution of NICA/MPD ECAL with new reconstruction methods

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JOURNAL OF INSTRUMENTATION 2019年第5期14卷 P05010-P05010页

作者： Wang, F. Han, D. Wang, Y. Shen, C. Li, Yu Tyapkin, I Rumenova, D. B. Li, Y. Tsinghua Univ Dept Engn Phys Beijing 100084 Peoples R China Tsinghua Univ Key Lab Particle & Radiat Imaging Minist Educ Beijing 100084 Peoples R China JINR Joint Curie 6 Dubna 141980 Moscow Region Russia

A Shashlyk-type electromagnetic calorimeter(ECal) will be used in the Multi-purpose Detector at Nuclotron-based Ion Collider facility to study the properties of nuclear matter. In this experiment, the ECal detector is responsible for measuring the energy and position of the incident particles, and identifying them with the information obtained from itself and other detectors. This paper analyzes the position resolution of the Tsinghua ECal modules using the data from a beam test inDESY. Several reconstruction methods are studied in detail. With a deep learning based algorithm, the position resolution of the prototypes achieves less than 3.8 mmfor 1.6 GeV electron beam, which is improved by about 30% compared to that of traditional charge center of gravity method.

关键词： Analysis and statistical methods Calorimeters data processing methods

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Ultrasonic camera: a matrix-based real-time ultrasonic imaging system for immersion applications

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JOURNAL OF INSTRUMENTATION 2019年第11期14卷

作者： Tarpara, E. G. Jain, H. Kumar, N. P. Patankar, V. H. HBNI Mumbai Maharashtra India BARC Mumbai Maharashtra India

The novel matrix-based real-time ultrasonic imaging using an ultrasonic camera for immersion application has been proposed in this paper. The proposed ultrasonic camera provides real-time images of mechanical components and the image size is equal to the field of view of the developed matrix-based transducer assembly. For the matrix-based ultrasonic imaging, the addressing-based analog multiplexing scheme has been proposed in such a way that all channels of the specific row are selected simultaneously such as the transducer excitation, data acquisition, data processing and transferring operations are performed concurrently. Similarly, the same operations are performed for remaining all rows sequentially. The developed ultrasonic camera further supports dynamic on-line reconfiguration of the analog front-end hardware, real-time hardware/software-based data processing and data transfer operation. For the experimentation, the entire matrix-based (5 x 5) ultrasonic imaging system for immersion applications has been designed, developed and evaluated in the laboratory. Here we present the performance evaluation of the developed matrix-based ultrasonic camera system by acquiring the real-time images of the water-immersed mechanical objects.

关键词： data acquisition circuits data processing methods Detection of defects Digital electronic circuits

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From the bottom to the top - reconstruction of t(t)over-bar events with deep learning

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JOURNAL OF INSTRUMENTATION 2019年第11期14卷

作者： Erdmann, J. Kallage, T. Kroeninger, K. Nackenhorst, O. TU Dortmund Lehrstuhl Expt Phys 4 Otto Hahn Str 4a D-44227 Dortmund Germany

The reconstruction of top-quark pair-production (t (t) over bar) events is a prerequisite for many top-quark measurements. We use a deep neural network, trained with Monte-Carlo simulated events, to reconstruct t (t) over bar decays in the lepton+jets final state. Comparing our approach to a widely-used kinematic fit, we find significant improvements in the correct assignment of jets to the partons from the decay, and we study the reconstruction performance of several kinematic top-quark properties. We document our workflow for the optimisation of the hyperparameters of the deep neural network. This workflow can be followed by experimental collaborations to retrain the network taking into account their detailed detector simulations.

关键词： Analysis and statistical methods data processing methods

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Design of the Guide Tube Calibration System for the JUNO experiment

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JOURNAL OF INSTRUMENTATION 2019年第9期14卷 T09005-T09005页

作者： Guo, Yuhang Zhang, Qingmin Zhang, Feiyang Xiao, Mengjiao Liu, Jianglai Qu, Eryuan Xi An Jiao Tong Univ Sch Nucl Sci & Technol Xian 710049 Shaanxi Peoples R China Shanghai Jiao Tong Univ Sch Phys & Astron Shanghai 200240 Peoples R China Univ Maryland Dept Phys College Pk MD 20742 USA Peking Univ Ctr High Energy Phys Beijing 100871 Peoples R China

The hangmen Underground Neutrino Observatory (JUNO) is designed to determine the neutrino mass hierarchy using a 20 kton liquid scintillator detector. To calibrate the detector boundary effect, the Guide Tube Calibration System (GTCS) has been designed to deploy a radioactive source along a given longitude on the outer surface of the detector. In this paper, we studied the physics case of this system via simulation, which leads to a mechanical design.

关键词： Detector alignment and calibration methods (lasers, sources, particle-beams) data processing methods Neutrino detectors Large detector systems for particle and astroparticle physics

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A digital pulse shortening method for the mitigation of pulse pile-up effect in scintillation radiation detectors

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JOURNAL OF INSTRUMENTATION 2019年第4期14卷

作者： Nakhostin, M. Taggart, M. P. Sellin, P. J. Univ Surrey Dept Phys Guildford GU2 7XH Surrey England

The pulse pile-up effect can significantly degrade the spectroscopic performance of scintillation radiation detectors at high counting rates. This paper reports on a digital pulse processing method for shortening the duration of scintillation pulses, thereby alleviating the pulse pile-up effect. The method operates based on replacing the decay-time constant of the scintillation pulses with a shorter decay-time constant. The details of the digital algorithm are presented and the performance of the method at a high counting rate of 795 kHz is experimentally examined with a NaI(Tl) detector. The effects of the pulse shortening on the spectroscopic performance of the system are also discussed.

关键词： data processing methods Digital signal processing (DSP) Scintillators and scintillating fibres and light guides

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Classification of unexploded ordnance-like targets with characteristic response in transient electromagnetic sensing

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JOURNAL OF INSTRUMENTATION 2019年第10期14卷 P10011-P10011页

作者： Chen, S. Jiang, H. Zhu, J. Qiu, Y. Zhang, S. Sci & Technol Near Surface Detect Lab Tonghuixi Rd Wuxi 214035 Jiangsu Peoples R China Jilin Univ Coll Elect Sci & Engn Qianjin St Changchun 130012 Jilin Peoples R China

Characteristic response parameterized in time-dependent target intrinsic polarizabilities can be used to discriminate unexploded ordnance (UXO) from harmless items. This study explains the measurement, analysis, and classification of UXO-like targets against data collected under laboratory-type conditions with a specially designed transient electromagnetic (TEM) system. After a brief description of the single dipole model and TEM system, the characteristic responses of all UXO-like targets have been measured with an improved long straight solenoid. The influence of the target shape and size on characteristic response is analyzed. Results show that targets of the same shape share similar power law function decay rate at an early time. The larger the target size is, the greater the response will be. The characteristic response for harmless targets decays faster than the UXOs, leading to a considerable difference in a later time, which can be used for target classification. When the characteristic response is parameterized as kt(-beta)e(-gamma) t in 100 ms, targets can be effectively separated with the fitted parameters k, beta and gamma. However, when fitted in 10 ms, the fitted parameter gamma may be thousands of times than the one fitted in 100 ms, resulting in classification failure. The normalized response combined with the fitting parameter beta can be used for target classification to overcome the instability of fitted parameter gamma in 10 ms. Finally, all UXOs are completely separated from harmless targets within 10 ms.

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

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