MODEL OF PHYSICAL PROCESSES IN PRIMARY AND SECONDARY CONVERTERS OF THE DETECTOR

The level of development and application of radiation technologies is largely determined by the state of nuclear instrumentation. The advent of modern semiconductor sensors for the first time linked nuclear instrumentation and electronics into a single complex - semiconductor detector. It combines semiconductor primary converter of ionizing radiation (sensor), a secondary converter of information from the sensor (electronics) and software for processing this information, interconnected in terms of the problem being solved and parameters. The structural diagram of detector consists of two main parts: a primary converter of ionizing radiation (IR) energy into an electrical signal - a sensor; secondary converter of this electrical signal. The characteristics of detector are mainly determined by the physical properties of the semiconductor crystal as a sensitive element of the primary converter, as well as by the features of the process of recording an electrical signal. The process of registering an IR consists in converting a non-electrical quantity characterizing it into an electrical signal. In other words, this converts one type of energy - the energy of IR - into another, more convenient for processing and accumulating information. A current or voltage pulse arises in the radiation sensor directly as a result of ionization of its active medium - a semiconductor; this pulse carries extensive information. First of all, it is correlated with the moment of time of the nuclear process. In addition, the pulse marks the fact that radiation is emitted within the solid angle at which the sensor is visible from the source. Pulse amplitude is often a measure of the energy loss of radiation in the sensor. The pulse shape is different for different types of radiation, as well as for different areas and angles of radiation hitting the sensor. In this work, a model of a gamma radiation detector has been created as a single system of primary and secondary converters. It contains physical analysis and analytical presentation of the processes occurring in the CdZnTe-sensor and electronic preamplifier. It is shown that the charge collection in the sensor differs in time, which leads to a spread of signal pulses in duration and amplitude. In this regard, model shows the need to use a charge-sensitive preamplifier. The main advantage of the model is solution to problem of optimizing signal-to-noise ratio in detector.

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DETECTOR SIMULATION FOR RADIATION MONITORING SYSTEMS

Collection of scientific works of the Military Institute of Kyiv National Taras Shevchenko University ◽

10.17721/2519-481x/2020/68-01 ◽

2020 ◽

pp. 5-13 ◽

Cited By ~ 1

Author(s):

O.V. Banzak ◽

O.V. Maslov ◽

V.A. Mokritsky ◽

O.I. Leschenko

Keyword(s):

Gamma Radiation ◽

Radiation Detector ◽

Field Method ◽

Structural Defects ◽

Physical Analysis ◽

Radiation Sensor ◽

Mobility Of Charge Carriers ◽

A Charge ◽

Radiation Sensors ◽

Detector Simulation

In the work, a model of primary transducer - gamma radiation sensor has been created. It is based on the following properties of a semiconductor crystal: maximum quantum efficiency; maximum mobility of charge carriers; minimum density of structural defects; maximum values of resistivity and density. The combination of these properties provides significant sensor sensitivity with a minimum crystal size. The inconsistency of this combination must be eliminated both in the process of crystal fabrication (for example, a high-resistance crystal is obtained by the simultaneous use of purification, components, and compensating doping) and subsequent processing by the methods proposed in this work (thermal field method, ionization annealing). To register small signals, it is necessary to have minimal loss currents at sufficiently high voltages applied to the sensor. This means that the semiconductor material must be highly resistive. Among the known materials for gamma radiation sensors, single crystals of CdxZn1-xTe solid solutions have an optimal combination of the properties listed above and the possibilities of their production. The creation of a model gamma-radiation detector as a single system of primary and secondary converters is considered. It contains physical analysis and analytical presentation of processes occurring in CdZnTe-sensor and electronic preamplifier. It is shown that the charge collection in the sensor differs in time, which leads to a spread of signal pulses in duration and amplitude. In this regard, the model shows need to use a charge-sensitive preamplifier.

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Organic semiconducting single crystals as solid-state sensors for ionizing radiation

Faraday Discussions ◽

10.1039/c4fd00102h ◽

2014 ◽

Vol 174 ◽

pp. 219-234 ◽

Cited By ~ 26

Author(s):

Beatrice Fraboni ◽

Andrea Ciavatti ◽

Laura Basiricò ◽

Alessandro Fraleoni-Morgera

Keyword(s):

Ionizing Radiation ◽

Single Crystals ◽

Organic Semiconductors ◽

Signal To Noise Ratio ◽

Low Cost ◽

Radiation Detectors ◽

Direct Conversion ◽

Electrical Signal ◽

Ambient Atmosphere ◽

High Radiation

So far, organic semiconductors have been mainly proposed as detectors for ionizing radiation in the indirect conversion approach, i.e. as scintillators, which convert ionizing radiation into visible photons, or as photodiodes, which detect visible photons coming from a scintillator and convert them into an electrical signal. The direct conversion of ionizing radiation into an electrical signal within the same device is a more effective process than indirect conversion, since it improves the signal-to-noise ratio and it reduces the device response time. We report here the use of Organic Semiconducting Single Crystals (OSSCs) as intrinsic direct ionizing radiation detectors, thanks to their stability, good transport properties and large interaction volume. Ionizing radiation X-ray detectors, based on low-cost solution-grown OSSCs, are here shown to operate at room temperature, providing a stable linear response with increasing dose rate in the ambient atmosphere and in high radiation environments.

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Adaptive identification methods of nonlinear random electrical signal

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209349 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 431-438

Author(s):

Jian Liu ◽

Lihui Wang ◽

Zhengqi Tian

Keyword(s):

Wavelet Transform ◽

Electric Vehicle ◽

Signal To Noise Ratio ◽

Sudden Change ◽

Electrical Signal ◽

Signal Recognition ◽

State Variable ◽

Signal Characteristics ◽

The Matrix ◽

Kalman Filter Algorithm

The nonlinearity of the electric vehicle DC charging equipment and the complexity of the charging environment lead to the complex and changeable DC charging signal of the electric vehicle. It is urgent to study the distortion signal recognition method suitable for the electric vehicle DC charging. Focusing on the characteristics of fundamental and ripple in DC charging signal, the Kalman filter algorithm is used to establish the matrix model, and the state variable method is introduced into the filter algorithm to track the parameter state, and the amplitude and phase of the fundamental waves and each secondary ripple are identified; In view of the time-varying characteristics of the unsteady and abrupt signal in the DC charging signal, the stratification and threshold parameters of the wavelet transform are corrected, and a multi-resolution method is established to identify and separate the unsteady and abrupt signals. Identification method of DC charging distortion signal of electric vehicle based on Kalman/modified wavelet transform is used to decompose and identify the signal characteristics of the whole charging process. Experiment results demonstrate that the algorithm can accurately identify ripple, sudden change and unsteady wave during charging. It has higher signal to noise ratio and lower mean root mean square error.

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Nuclear instrumentation. Thickness measurement systems utilizing ionizing radiation. Definitions and test methods

10.3403/01326711 ◽

1998 ◽

Keyword(s):

Ionizing Radiation ◽

Thickness Measurement ◽

Test Methods ◽

Measurement Systems ◽

Nuclear Instrumentation

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Fiber optic ionizing radiation detector

IEEE Transactions on Nuclear Science ◽

10.1109/23.159686 ◽

1992 ◽

Vol 39 (4) ◽

pp. 674-679 ◽

Cited By ~ 3

Author(s):

J.J. Suter ◽

J.C. Poret ◽

M. Rosen

Keyword(s):

Ionizing Radiation ◽

Fiber Optic ◽

Radiation Detector

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Combined Near-Infrared Raman Microprobe and Laser Trapping System: Application to the Analysis of a Single Organic Microdroplet in Water

Applied Spectroscopy ◽

10.1366/0003702981943789 ◽

1998 ◽

Vol 52 (3) ◽

pp. 339-342 ◽

Cited By ~ 26

Author(s):

Katsuhiro Ajito

Keyword(s):

Raman Spectrum ◽

Near Infrared ◽

Laser Light ◽

Signal To Noise Ratio ◽

Peak Height ◽

Laser Spot ◽

Laser Trapping ◽

Raman Microprobe ◽

A Charge ◽

Nir Laser

A combined Raman microprobe and laser trapping system using near-infrared (NIR) laser light was developed for the investigation of single organic microdroplets. The NIR laser light is noninvasive and reduces fluorescence interference in the Raman spectrum for organic molecules. The focused laser beam used for the laser trapping of a microdroplet serves simultaneously as the laser microprobe for Raman measurement. With this system, the focused laser spot is about 1 μm in diameter, which is small enough for the laser trapping of a single toluene microdroplet in water. The system also makes it possible to visualize a focused laser spot together with a laser-trapped microdroplet by using holographic notch filters. The Raman spectrum for a single laser-trapped toluene microdroplet can be obtained from below 100 cm−1 to above 3000 cm−1 with a charge-coupled device (CCD) detector. Fluorescence interference in the Raman spectrum is completely removed by using NIR laser light. The signal-to-noise ratio (SNR), defined as the ratio of the peak height to the standard deviation of the baseline noise in the spectrum, exceeded 250 for the 1003 cm−1 band of a toluene microdroplet at 1 s, which is sufficient to allow identification of the molecular species of a microdroplet.

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Advances in Monte-Carlo code TRIPOLI-4®’s treatment of the electromagnetic cascade

EPJ Web of Conferences ◽

10.1051/epjconf/201817001008 ◽

2018 ◽

Vol 170 ◽

pp. 01008

Author(s):

Davide Mancusi ◽

Alice Bonin ◽

François-Xavier Hugot ◽

Fadhel Malouch

Keyword(s):

Monte Carlo ◽

Nuclear Reactor ◽

Thick Target ◽

Monte Carlo Code ◽

Reactor Physics ◽

Validation And Verification ◽

Electron Positron ◽

A Charge ◽

Charge Deposition ◽

Nuclear Instrumentation

TRIPOLI-4® is a Monte-Carlo particle-transport code developed at CEA-Saclay (France) that is employed in the domains of nuclear-reactor physics, criticality-safety, shielding/radiation protection and nuclear instrumentation. The goal of this paper is to report on current developments, validation and verification made in TRIPOLI-4 in the electron/positron/photon sector. The new capabilities and improvements concern refinements to the electron transport algorithm, the introduction of a charge-deposition score, the new thick-target bremsstrahlung option, the upgrade of the bremsstrahlung model and the improvement of electron angular straggling at low energy. The importance of each of the developments above is illustrated by comparisons with calculations performed with other codes and with experimental data.

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Optical spatial modulation design

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2019.0195 ◽

2020 ◽

Vol 378 (2169) ◽

pp. 20190195 ◽

Cited By ~ 2

Author(s):

T. Cogalan ◽

H. Haas ◽

E. Panayirci

Keyword(s):

Mimo Systems ◽

Direct Detection ◽

Signal To Noise Ratio ◽

Multiple Input Multiple Output ◽

Pulse Amplitude ◽

Visible Light Communication ◽

Performance Model ◽

Spatial Modulation ◽

Error Performance ◽

Led Array

Visible light communication (VLC) systems are inherently signal-to-noise ratio (SNR) limited due to link budget constraints. One favourable method to overcome this limitation is to focus on the pre-log factors of the channel capacity. Multiple-input multiple-output (MIMO) techniques are therefore a promising avenue of research. However, inter-channel interference in MIMO limits the achievable capacity. Spatial modulation (SM) avoids this limitation. Furthermore, the performance of MIMO systems in VLC is limited by the similarities among spatial channels. This limitation becomes particularly severe in intensity modulation/direct detection (IM/DD) systems because of the lack of phase information. The motivation of this paper is to propose a system that results in a multi-channel transmission system that enables reliable multi-user optical MIMO SM transmission without the need for a precoder, power allocation algorithm or additional optics at the receiver. A general bit error performance model for the SM system is developed for an arbitrary number of light-emitting diodes (LEDs) in conjunction with pulse amplitude modulation. Based on this model, an LED array structure is designed to result in spatially separated multiple channels by manipulating the transmitter geometry. This article is part of the theme issue ‘Optical wireless communication’.

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