Good Time Resolution Research Articles

EMG Signal Based Pattern Recognition of Grasping Movement Using MODWT And Weighted K- Nearest Neighbor

This study purposed and evaluates a method based on weighted K-NN classification of surface Electromyogram (sEMG) signals. The sEMG signal classification plays the key role in designing a prosthetic for amputee persons. Wavelet transform is new signal processing technique, which provides better resolution in time and frequency domain simultaneously. Due to these wavelet properties, it can be effectively used in processing the sEMG signal to determine certain amplitude changes at certain frequencies. This paper propose a Maximal overlap Discrete Wavelet Transform (MODWT) approach for Weighted K-NN classifier for classification of sEMG signals based Grasping movements. At level 5 signal decomposition using MODWT, useful resolution component of the sEMG signal is obtained. In this paper Time-domain (TD) features set is used, which shows a decent performance. In WKNN, use a square-inverse weighted technique to improve the performance of the K-NN. Hence, a novel feature set obtained from decomposed signal using MODWT is used to improve the performance of sEMG for classification. MODWT was used for de-noising and time scale feature extraction of sEMG signals. Several WKNN classifiers are tested to optimize classification accuracy and computational problems. PCA is use to reduce the size of the level 5 decomposed data. WKNN performance evaluation on K=10 values with or without PCA. Six hand grasping movements have been classified, results indicate that this method allows the classification of hand pattern recognition with high precision.

Inverse Low Gain Avalanche Detectors (iLGADs) for precise tracking and timing applications

Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 mm2; and a good timing resolution, around 20–30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100% fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented.

Bulk Micromegas fabrication at JINR

Bulk Micromegas detectors are well known for their good spatial and time resolution, and simplicity of manufacturing and maintenance. They are widely applied in various experiments. Recently, the infrastructure for Bulk Micromegas development was established at the Joint Institute for Nuclear Research. The fabrication technology is described in this article, as well as the performance of the first assembled prototype is presented.

A Novel DOI Positioning Algorithm for Monolithic Scintillator Crystals in PET Based on Gradient Tree Boosting

Monolithic crystals are examined as an alternative to segmented scintillator arrays in positron emission tomography (PET). Monoliths provide good energy, timing and spatial resolution including intrinsic depth of interaction (DOI) encoding. DOI allows reducing parallax errors (radial astigmatism) at off-center positions within a PET ring. We present a novel DOI-estimation approach based on the supervised machine learning algorithm gradient tree boosting (GTB). GTB builds predictive regression models based on sequential binary comparisons (decision trees). GTB models have been shown to be implementable in FPGA if the memory requirement fits the available resources. We propose two optimization scenarios for the best possible positioning performance: One restricting the available memory to enable a future FPGA implementation and one without any restrictions. The positioning performance of the GTB models is compared with a DOI estimation method based on a single DOI observable (SO) comparable to other methods presented in literature. For a 12 mm high monolith, we achieve an averaged spatial resolution of 2.15 mm and 2.12 mm FWHM for SO and GTB models, respectively. In contrast to SO models, GTB models show a nearly uniform positioning performance over the whole crystal depth.

Development of 3D trenched-electrode pixel sensors with improved timing performance

The high luminosities expected at collider experiments over the coming years will put stringent requirements on the vertex detectors used in these experiments. The increased pile up will require improved spatial and timing resolution to distinguish between particle tracks while also requiring the devices to have an increased radiation hardness. 3D sensors have already been proven as a viable technology with good radiation hardness due to the short distance between electrodes and are also capable of achieving the desired spatial resolution. 3D sensors have so far not been fully exploited to achieve good timing resolution due to the non-uniformity of the electric field in the sensors. The TIMESPOT project aims to develop a complete integrated system for tracking with high precision in both space and time. Novel 3D sensors are being developed for this purpose, providing the normal advantages of this technology (such as radiation hardness and low depletion voltage), with the trench geometry also providing more uniform electric and weighting fields, optimized for timing. TCAD simulations have been carried out to optimize the design of these sensors and to estimate their performance, finding a compromise between the capacitance and the intrinsic speed. Technological tests have also been carried out at FBK to determine the manufacturing constraints of these sensors. A first layout including pixel sensors compatible with the TIMEPIX read-out chip and several test structures has been prepared and production of the first batch of sensors is underway.

Muon detectors and Micro-Pattern Gas Detectors

Almost all experimental apparatuses at existing colliders employ large muon systems located after all other subdetectors. Given the large size of most of the experimental detectors, the existing muon system has to cover areas of a few thousand square meters. It can be anticipated that future detectors at future colliders will be even larger in size. Therefore, for a practical reason of cost, the most suited detectors to realize these large muon systems are gas detectors. In particular, in recent years, Micro-Pattern Gas Detectors (MPGDs) have enjoyed very interesting developments, providing several new types of detectors with very good spacial and time resolution, high-rate capability and high radiation tolerance. MPGDs also have the distinct advantage of being, at least for some detectors and some parts of them, mass produceable by industry, since they employ materials and manufacturing procedures that are extensively used for Printed Circuit Boards (PCBs) production. A particularly innovative MPGD, the [Formula: see text]RWell, is described as a possible candidate to build large muon systems for future colliders. The results obtained so far with this new technology are reported.

Segmented YSO scintillation detectors as a new β-implant detection tool for decay spectroscopy in fragmentation facilities

A newly developed segmented YSO scintillator detector was implemented for the first time at the RI-beam Factory at RIKEN Nishina Center as an implantation-decay counter. The results from the experiment demonstrate that the detector is a viable alternative to conventional silicon-strip detectors with its good timing resolution and high detection efficiency for ${\rm \beta}$ particles. A Position-Sensitive Photo-Multiplier Tube (PSPMT) is coupled with a $48\times48$ segmented YSO crystal. To demonstrate its capabilities, a known short-lived isomer in $^{76}$Ni and the ${\rm \beta}$ decay of $^{74}$Co were measured by implanting those ions into the YSO detector. The half-lives and ${\rm \gamma}$-rays observed in this work are consistent with the known values. The ${\rm \beta}$-ray detection efficiency is more than 80~\% for the decay of $^{74}$Co.

Particle identification with DIRCs at PANDA

The DIRC technology (Detection of Internally Reflected Cherenkov light) offers an excellent possibility to minimize the form factor of Cherenkov detectors in hermetic high energy detectors. The PANDA experiment at FAIR in Germany will combine a barrel-shaped DIRC with a disc-shaped DIRC to cover an angular range of 5 to 140 degrees. Particle identification for pions and kaons with a separation power of 3 standard deviations or more will be provided for momenta between 0.5 GeV/c and 3.5 GeV in the barrel region and up to 4 GeV/c in the forward region. Even though the concept is simple, the design and construction of a DIRC is challenging. High precision optics and mechanics are required to maintain the angular information of the Cherenkov photons during multiple internal reflections and to focus the individual photons onto position sensitive photon detectors. These sensors must combine high efficiencies for single photons with low dark count rates and good timing resolution at high rates. The choice of radiation hard fused silica for the optical material and of MCP-PMT photon sensors is essential for DIRC detectors to survive in an environment of radiation and strong magnetic field. The two DIRC detectors differ in the focusing optics, in the treatment of chromatic dispersion and in the electronic readout systems. The technical design of the two DIRC detectors and their validation by testing prototypes in a mixed particle beam at CERN are presented.

Performance of a depth encoding PET detector module using light sharing and single-ended readout with SiPMs

Detectors with depth encoding capability, good energy resolution and good timing resolution are required to develop high performance whole body and total body PET scanners. In this work, an 8 × 8 LYSO array with crystal size of 3 × 3 × 20 mm3 was fabricated by using coupling materials that included 5 mm optical glue, 9 mm triangle ESR reflector and 6 mm rectangle ESR reflector from the top to the bottom in between adjacent crystals in one direction. The LYSO array was single-ended read out by an 8 × 8 SiPM array with one-to-one coupling. Row and column summing circuit was used to read out the SiPM signals. The depth of interaction (DOI) of the detector was measured with the depth dependent light sharing between adjacent crystals while maintaining acceptable energy resolution and timing resolution. The performance of the detector module was evaluated. All crystals can be clearly resolved from the measured flood histogram. An average DOI resolution of 4.62 mm and an average timing resolution of 518 ps are obtained for events with E > 400 keV. The average energy resolution of the detector is 13.5%. This work provides a cost-effective depth encoding detector module that can be used to build high performance whole body and total body PET scanners in the future.

Error Optimization in Electrical Power Quality Monitoring Data

In the application of electrical power quality control, the necessity for data processing becomes very important. The measurement data obtained is the latest data and measured in real time with good time resolution and with low error. The object of research is the quality of electric power, the research is about ways of measuring quality of electrical power to obtain accurate data in accordance with actual conditions. This method is capable of measuring data of electrical power quality that changes very quickly with a low error. This data is used as a basis for improving the quality of electric power accurately and accurately.

Coincident detection of Cherenkov light from higher energetic electrons using silicon photomultipliers

Due to their very fast signal rise time in the order of 1 ns, Silicon-Photomultipliers have become of increasing interest for many experiments that require very good timing resolution. With the prospect of an application in medical imaging techniques like a Compton Camera or TOF-PET, a coincident detection of Cherenkov photons from electrons in the MeV range in PMMA has been performed. A 4x4 SiPM-array was used for this purpose and a timing resolution of 242 ps has been achieved. A spatial sensitivity for an electron source location could be shown using accumulated coincident light signals. Obtained results are in good agreement with theoretical calculations taking fundamental detector and set-up properties into account. These measurements constitute an important step towards the feasibility of a successful electron detection in a Compton Camera.

Space charge polarization in irradiated single crystal CVD diamond

Single crystal CVD (scCVD) diamond is an attractive material for particle detection in high energy physics for its good time resolution and reported outstanding radiation tolerance. In addition to direct signal loss via charge carrier trapping, polarization effect, caused by non-homogeneous filling of trap defects, is a known cause of signal degradation in irradiated scCVD diamond. This phenomenon was studied by intentionally polarizing irradiated diamonds. Even the relatively lightly irradiated (1014 protons/cm2) diamonds exhibited strong enough polarization to collapse the electric field with moderate rate of 5 MeV alpha particles. The transient current measurements were reproduced with TCAD simulations. The hypothesis that the polarization is caused by single neutral defect type in the bulk, was tested using two generic models. Neither one has a satisfactory agreement with the measurement data, which indicates that trapping at the interfaces play a significant role in space charge polarization.

Simulation of a Fast Timing Micro-Pattern Gaseous Detector for TOF-PET and future accelerators

Simulation is a powerful tool for designing new detectors and guide the construction of new prototypes. Advances in photolithography and micro-electronics led to the development of a new family of devices named Micro-Pattern Gas Detectors (MPGDs) [1], with main features: flexible geometry; high rate capability (> MHz/cm2); excellent spatial resolution ( 100µ m); good time resolution (5-10 ns); and reduced radiation length. A new detector layout, named Fast Timing MPGD (FTM), has been recently proposed [2] that would combine both the high spatial resolution and high rate capability of the MPGDs, while improving the time resolution with nearly two orders of magnitude to ~100ps. However charged particle timing with gaseous detector time resolution below 100 ps has been established with another detection scheme [3], this approach might not be able to sustain high particle rates. This contribution investigates the use of the FTM technology for an innovative TOF-PET imaging detector and emphases the importance of full detector simulation to guide the design of the detector geometry and performance.

Observation of Short‐Period Ionospheric Disturbances Using a Portable Digital Ionosonde at Sanya

AbstractA number of ionosondes have been operated in China to detect ionospheric disturbances for many years. These ionosondes, however, are not very suitable for the short‐period (<15 min) disturbances due to their poor time resolutions (>5 min). During recent years, the Institute of Geology and Geophysics, Chinese Academy of Sciences, together with the South Central University for Nationalities has been developing a portable digital ionosonde (PDI) equipped with the capability to detect and characterize small‐scale/short‐period ionospheric disturbances and to be quickly assembled and set up at temporary field stations for low‐latitude campaign coordinated observations. The PDI uses a set of technologies (e.g., code multiplexing and antenna/transmitter matching) that allow it to obtain quality Doppler ionograms at a good time resolution with small transmitting antennas. A preliminary analysis of observations by the PDI at Sanya (18.3°N, 109.6°E) shows the presence of ionospheric disturbances with periods ranging between several and tens of minutes. Interestingly, the disturbances (with different periods) were found to simultaneously occur at different F region altitudes, for example, with periods of ~5 and 20 min below and above ~180 km, respectively. The absence of shorter‐period disturbance at higher altitude is consistent with acoustic gravity waves through the region with intrinsic periods above the Brunt‐Väisälä period. The short‐period disturbances observed in F region bottomside are not evident in total electron content. The results demonstrate the capability of PDI to detect ionospheric disturbances with temporal scales down to a few minutes in routine ionogram mode. Future prospects of PDI are outlined.

Development of the FTM technology for TOF-PET

Abstract Gas detector research focused in particular on the radiation induced processes leading to discharge breakdown led, thanks to advances in photolithography and micro-electronics, to the development of a family of resistant devices named Micro-Pattern Gas Detectors (MPGDs) (Titov and Ropelewski 2013, [1] ). The main features of the MPGDs are: a flexible geometry; a high rate capability ( > MHz/cm 2 ); an excellent spatial resolution ( μ m ) ; a good time resolution (5–10 ns); and a reduced radiation length. A new detector layout, named Fast Timing MPGD (FTM), has been recently proposed (De Oliveira and Maggi 2015, [2] ). The FTM would combine both the high spatial resolution and high rate capability of the MPGDs while improving the time resolution with nearly two orders of magnitude to ∼ 100 ps. This contribution studies the possibility to adapt the FTM technology for TOF-PET imaging.

High performance DAQ for muon spectroscopy experiments

The main features of the Data AcQuisition systems for the FAMU (on muonic atom physics) and CHNET_TANDEM (on the development of nondestructive techniques to archaeometry) INFN projects will be described. Both the experiments exploit the RIKEN-RAL Muon Facility beam of (20,120)MeV∕c muons and the same experimental setup, which includes a wide range of detectors: HPGe detectors for high resolution spectroscopy; LaBr3 scintillators, with both PMT and SiPM readout, for fast and high time resolution spectroscopy; several layers of 32 SiPM readout scintillating fibers for beam monitoring with good spatial and time resolution. The performance of the DAQ in terms of conditioning and processing of such a large number of different detector signals, data storage and analysis and a few examples of the results will be presented.

Machine Learning for Waveform Spectral Analysis on Nuclear Explosion Signal and Performance of Broadband Vertical Component

Machine learning of nuclear explosion signal waveform is core component to realize the characteristics of signal. The processing of waveform explosion signal is broadly used for analysis of real time explosion signal. The numerous wavelet filters are developed by spectral synthesis using machine learning python to realize the signal characteristics. Our paper aims to generate the performance of nuclear explosion signal and processing the waveform from seismic sensor by using Continuous Wavelet Transform (CWT). CWT is also clearly to identify of spectral amplitudes and frequency-energy from component of signal seismic performed by Broadband Network in Indonesia. Finally, by machine learning python allows good time resolution for identified and performed of seismic signal from broadband which deployed in Indonesia.

Sparse time-frequency representation based on multiwindow discrete Gabor transform

The multiwindow discrete Gabor transform (M-DGT) is an important time-frequency analysis tool in many applications. In this paper, sparse time-frequency representation (TFR) based on M-DGT with sparse regularization theory is presented. The M-DGT is first formulated as a convex constrained optimization model by minimizing the objective function with a mixed [Formula: see text]–[Formula: see text] norm of the M-DGT coefficients. Then, an iterative algorithm based on the split Bergman method is utilized to compute the sparse Gabor time-frequency spectrum of the analyzed signal. According to the Heisenberg uncertainty principle, using an analysis window with good time resolution in M-DGT will lead to the Gabor TFR with high frequency resolution and vice versa. To obtain the sparse TFR with good time-frequency resolution (or concentration), the sparse spectra of M-DGT can be combined by the arithmetic average or the geometric average. Numerical experiments clearly show that the proposed method is an effective and powerful tool for analyzing nonstationary signals, by which the high time-frequency concentration (or resolution) of the Gabor time-frequency spectrum can be obtained as compared to traditional M-DGT.

A standalone simulation framework of the MRPC detector read out in waveforms

Dedicated detector simulations are very important for the success of high energy physics experiments. They not only bring benefits to the optimization of the detectors, but can also improve the precision of the physics results. To design a Multi-gap Resistive Plate Chamber (MRPC) with a very good time resolution, a detailed monte-carlo simulation of the detector is needed and described in this paper. The simulation can produce detector signal waveforms which contain a complete information about the events. The detector performance filled with different gas mixtures is studied, and comparisons between simulation and experimental results show a good agreement.

Gradient Tree Boosting-Based Positioning Method for Monolithic Scintillator Crystals in Positron Emission Tomography

Monolithic crystals are considered as an alternative for complex segmented scintillator arrays in positron emission tomography systems. Monoliths provide high sensitivity, good timing, and energy resolution while being cheaper than highly segmented arrays. Furthermore, monoliths enable intrinsic depth of interaction capabilities and good spatial resolutions (SRs) mostly based on statistical calibrations. To widely translate monoliths into clinical applications, a time-efficient calibration method and a positioning algorithm implementable in system architecture such as field-programmable gate arrays (FPGAs) are required. We present a novel positioning algorithm based on gradient tree boosting (GTB) and a fast fan beam calibration requiring less than 1 h per detector block. GTB is a supervised machine learning technique building a set of sequential binary decisions (decision trees). The algorithm handles different sets of input features, their combinations and partially missing data. GTB models are strongly adaptable influencing both the positioning performance and the memory requirement of trained positioning models. For an FPGA-implementation, the memory requirement is the limiting aspect. We demonstrate a general optimization and propose two different optimization scenarios: one without compromising on positioning performance and one optimizing the positioning performance for a given memory restriction. For a 12 mm high LYSO-block, we achieve an SR better than 1.4 mm FWHM.