Temat: photon counting - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: High speed signal processing for photon counting X-ray detection
Autorzy:: Shinomiya, B.
Koike, A.
Morii, H.
Okunoyama, T.
Neo, Y.
Mimura, H.
Aoki, T.
Tematy:: X-ray
CdTe
photon counting; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Powiązania:: https://bibliotekanauki.pl/articles/385292.pdf Link otwiera się w nowym oknie
Opis:: Recently practical X-ray measurement systems are demanded energy distinction function. Photon-counting CdTe semiconductor detectors have a high energy resolution in a low count rate condition at room temperature. However, the energy resolution is decreased by pile-up phenomenon in a high count rate condition. In conventional signal processing, processing time estimated X-ray photon energy from the pulse waveform is about tens of microseconds. This time is depended on the pulse decay time. This paper purposes to maintain the high energy resolution by changing the signal-processing algorithm, which derived the pulse rise height of the output waveform from the CdTe detector in a high count rate condition. As a result, the pulse rise time required to estimate the pulse rise height was short about 100 ns at incident X-ray energy 60 keV. As the result of energy spectrum by using this data, the FWHM of about 11keV (at 60 keV) when the count rate of 500 kcps. This result shows the possibility that the photon counting sensor has application for the high count rate imaging without decrease of the high energy resolution.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Digital subpixel algorithm for small pixel photon counting devices
Autorzy:: Krzyżanowska, Aleksandra
Otfinowski, Piotr
Tematy:: charge sharing
subpixel algorithm
hybrid pixel detectors
photon counting; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Powiązania:: https://bibliotekanauki.pl/articles/59112868.pdf Link otwiera się w nowym oknie
Opis:: Hybrid pixel detectors are segmented devices widely used for photon detection. They consist of a sensor and readout electronics bonded together. Due to their hybrid structure, sensors of different materials can be used to register a wide range of photon energies. Moreover, the devices working in a single photon counting (SPC) mode allow registering each incoming photon separately, providing noiseless imaging. The spatial resolution of the detectors and photon count rate registered per unit area can be improved by reducing pixel size. However, small-pixel devices suffer from charge sharing. The charge sharing between pixels can be observed if the charge cloud generated in the photon-sensor event spreads due to diffusion and repulsion. Several anti-charge-sharing algorithms exist and some have been successfully implemented inside the ASICs readout. Even though they allow the allocation of the event to the proper pixel and reconstruction of the total photon energy, the detector resolution is limited by the readout channel area which must be large enough to fit the complex mixed-mode functionality. The article presents the simulations of an alternative solution which can improve both spatial resolution and high-count-rate performance. In the authors’ approach, charge sharing is regarded as a positive effect which can be used to estimate the photon interaction position with subpixel resolution. The algorithm is evaluated to improve detection efficiency and required pixel area for implementation in deep submicron technologies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Time Correlated Single Photon Counting System for Optical Measurements
Autorzy:: Trybuła, A.
Domański, G.
Konarzewski, B.
Marzec, J.
Zaremba, K.
Kurjata, R.
Dziewiecki, M.
Smolnik, A.
Ziembicki, M.
Tematy:: time correlated single photon counting
photomultiplier tube
optical techniques; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226833.pdf Link otwiera się w nowym oknie
Opis:: The high sensitivity time correlated single photon counting system (with photomultiplier tube) for biomedical measurements was designed and tested. Photon time of flight through a parafine wax phantom was modeled by Monte Carlo simulation and next measured by the device. Mean time delay introduced by a phantom is in a good agreement with simulation results. The results presented in this paper demonstrate the feasibility of measuring the optical response with the device.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Simulation study on improving the spatial resolution of photon-counting hybrid pixel X-ray detectors
Autorzy:: Krzyżanowska, Aleksandra
Szczygieł, Robert
Tematy:: charge sharing
subpixel resolution
pixel detector
hit allocation
single photon counting; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Powiązania:: https://bibliotekanauki.pl/articles/2063889.pdf Link otwiera się w nowym oknie
Opis:: Hybrid pixel radiation detectors with a direct photon-to-charge conversion working in a single photon counting mode have gained increasing attention due to their high dynamic range and noiseless imaging. Since sensors of different materials can be attached to readout electronics, they enable work with a wide range of photon energies. The charge-sharing effect observed in segmented devices, such as hybrid pixel detectors, is a phenomenon that deteriorates both spatial resolution and detection efficiency. Algorithms that allow the detection of a photon irrespective of the charge-sharing effect are proposed to overcome these limitations. However, the spatial resolution of the detector can be further improved beyond the resolution determined by the pixel size if information about the chargé proportions collected by neighbouring pixels is used to approximate the interaction position. In the article, an approach to achieve a subpixel resolution in a hybrid pixel detector working in the single photon counting mode is described. Requirements and limitations of digital inter-pixel algorithms which can be implemented on-chip are studied. In the simulations, the factors influencing the detector resolution are evaluated, including size of a charge cloud, number of virtual pixel subdivisions, and detector parameters.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: A camera for scanning objects in motion based on an integrated detection system working in on-chip TDI mode
Autorzy:: Żołądź, Mirosław
Tematy:: x-rays
application-specific integrated circuit
single-photon counting
time domain integration; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Powiązania:: https://bibliotekanauki.pl/articles/59112883.pdf Link otwiera się w nowym oknie
Opis:: The paper presents an X-ray camera for testing moving objects. A typical application of such cameras is scanning products on an industrial production line. Currently, the most popular device detecting radiation in this type of camera consists of a pixel line based on scintillator detectors. Unfortunately, increasing its resolution automatically involves reducing the pixel size and reducing the signal-to-noise ratio. This is where the time domain integration method comes in handy, increasing the resolution without degrading the signal-to-noise ratio. The camera presented in this paper is based on an application-specific integrated circuit dedicated to this purpose. The application-specific integrated circuit core is a pixel matrix operating in a single-photon counting mode. Its architecture was designed to implement the time domain integration method and construct high-resolution cameras with a large scanning area. The article also describes the hardware and software of the application-specific integrated circuit readout system.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Autorzy:: Tokgoz, Nazime
Algin, Oktay
Cademartiri, Filippo
Opis:: Photon-counting detector computed tomography (PCD-CT) devices have recently been introduced into practice, despite photon-counting detector technology having been studied for many years. PCD-CT devices are expected to provide advantages in dose reduction, tissue specificity, artifact-free imaging, and multi-contrast demonstration capacity. Noise reduction and increased spatial resolution are expected using PCD-CT, even under challenging scanning conditions. Some experimental or preliminary studies support this hypothesis. This pictorial review illustrates the features of PCD-CT systems, particularly in the interventional field. PCD-CT offers superior image quality and better lesion discrimination than conventional CT techniques for various conditions. PCD-CT shows significant improvements in many aspects of vascular imaging. It is still in its early stages, and several challenges have been identified. Also, PCD-CT devices have some important caveats. The average cost of these devices is 3 to 4 times higher than conventional CT units. This additional cost must be justified by improved clinical benefits or reduced clinical harms. Further investigations will be needed to resolve these issues.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 7.

Tytuł:: Tomografia spektralna
Spectral tomography
Autorzy:: Pawałowski, Bartosz
Paluszyńska, Marta
Charmacińska, Magdalena
Bąk, Olga
Graczyk, Kinga
Świątek, Katarzyna
Wosicki, Maksymilian
Piotrowski, Tomasz
Tematy:: tomografia spektralna
tomografia dwuenergetyczna
tomografia komputerowa
tomografia zliczająca fotony
spectral tomography
dual energy tomography
computed tomography
photon counting tomography; Pokaż więcej
Wydawca:: Indygo Zahir Media
Powiązania:: https://bibliotekanauki.pl/articles/58906530.pdf Link otwiera się w nowym oknie
Opis:: W pracy przedstawiono podstawy fizyczne oraz metody realizacji obrazowania spektralnego w tomografii komputerowej. Opisano różnice między metodami zaimplementowanymi komercyjnie w różnych typach tomografów komputerowych. W oparciu o przegląd literaturowy wymieniono możliwe zastosowania tych metod oraz potencjalne zyski wynikające z ich stosowania w porównaniu z klasycznymi metodami obrazowania tomograficznego.
The study presents the physical basics and methods of performing spectral imaging in computed tomography (CT). The differences between the commercially implemented methods in various CT machines are described. Based on the literature review, possible applications of these methods and potential benefits resulting from their use in comparison with classical methods of CT imaging were listed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: A time-domain pulse amplitude and width discrimination method for photon counting
Autorzy:: del Mar Correa, M.
Pérez, F. R.
Tematy:: field-programmable gate array
time-to-digital converter
spectroscopy
photomultiplier
photon counting
discriminator
after-pulsing
low-voltage differential signalling; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/220971.pdf Link otwiera się w nowym oknie
Opis:: This work shows a time-domain method for the discrimination and digitization of parameters of voltage pulses coming from optical detectors, taking into account the presence of electronic noise and afterpulsing. Our scheme is based on an FPGA-based time-to-digital converter as well as an adjustable-threshold comparator complemented with commercial elements. Here, the design, implementation and optimization of a multiphase TDC using delay lines shorter than a single clock period is also described. The performance of this signal processing system is discussed through the results from the statistical code density test, statistical distributions of measurements and information gathered from an optical detector. Unlike dual voltage threshold discriminators or constant-fraction discriminators, the proposed method uses amplitude and time information to define an adjustable discrimination window that enables the acquisition of spectra.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Detection of different types of salt present in natural water by the absortion – fluorescent probes.
Wykrywanie różnych typów soli występujących w wodach naturalnych przez sondy absorpcyjno-fluorescencyjne.
Autorzy:: Wrona, Beata
Opis:: There was synthesized a derivative of pyrazoloquinoline (2-[(2-hydroxyethyl)-(1,3,4-triphenyl-1H-pyrazolo[3,4-b]quinolin-6-ylmethyl)amino]ethanol (L1). This compound is known as a fluorescent indicator of cations. There were used fluorescent methods to determine concentrations of cations Ca2+, Na+ and boronic acid in acetonitrile solutions and also in solutions containing certain (small) addition of water. There was used TCSPC method – Time-Correlated Single Photon Counting, a method of correlated counting of individual photons, which allowed the measurement of fluorescence decay function and the stationary method using a spectrofluorimeter for measuring the intensity of fluorescence which allowed the quantitative description of the process of formation of complexes L1 with certain inorganic cations by the calibration curve showing the dependence of the fluorescence intensity as a function of analytical concentration of cations.
Zsyntetyzowano pochodną pyrazolochinoliny (2-[(2-hydroksyetyl)-(1,3,4-trifenyl-1H-pyrazolo[3,4-b]chinolin-6-ylmetyl)-amino]etanol (L1). Związek ten jest znany jako fluorescencyjny wskaźnik kationów. Zastosowano metody fluorescencyjne do oznaczania stężeń kationów Ca2+, Na+ i kwasu boronowego w roztworach acetonitrylowych oraz w roztworach zawierających pewien (niewielki) dodatek wody. Wykorzystano pomiary czasowo – rozdzielcze, czyli metodę czasowo skorelowanego zliczania pojedynczych fotonów, która pozwoliła na mierzenie funkcji zaniku fluorescencji, a także metodę stacjonarną z wykorzystaniem spektrofluorymetru, służącą do pomiaru intensywności fluorescencji, która umożliwiła opis ilościowy procesu tworzenia się kompleksów L1 z niektórymi kationami nieorganicznymi za pomocą krzywej wzorcowej, przedstawiającej zależność intensywności fluorescencji w funkcji analitycznego stężenia kationów.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Inne

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Skocz do pozycji: 10.

Tytuł:: Obrazowanie rentgenowskie – nie tylko pomiar osłabienia promieniowania
X-ray imaging – not only measuring the attenuation of radiation
Autorzy:: Skrzyński, Witold
Tematy:: obrazowanie rentgenowskie
detektory zliczające fotony
rozpraszanie wsteczne
wymuszona fluorescencja
obrazowanie kontrastowo-fazowe
X-ray imaging
photon counting detectors
backscatter
X-ray fluorescence
phase-contrast imaging; Pokaż więcej
Wydawca:: Indygo Zahir Media
Powiązania:: https://bibliotekanauki.pl/articles/985845.pdf Link otwiera się w nowym oknie
Opis:: Medyczne obrazowanie rentgenowskie jest oparte na pomiarze osłabienia wiązki promieniowania przechodzącej przez tkanki pacjenta. Osłabienie wiązki nie jest jednak jedynym efektem oddziaływania promieniowania w tkankach. Oprócz osłabienia obserwujemy rozproszenie (także wsteczne), tworzenie promieniowania charakterystycznego (wymuszona fluorescencja), a nawet zmianę fazy i załamanie fali elektromagnetycznej. Artykuł zawiera krótki przegląd literatury dotyczącej możliwych zastosowań tych zjawisk w obrazowaniu medycznym.
X-ray medical imaging is based on measuring the attenuation of the radiation beam passing through the patient’s tissues. However, beam attenuation is not the only effect of radiation interaction in tissues. In addition to attenuation, we can also observe scattering (including backscattering), creation of characteristic radiation (X-ray fluoerescence), and even phasechange and refraction of the electromagnetic wave. The article contains a brief review of the literature on the possible applications of these phenomena in medical imaging.
Dostawca treści:: Biblioteka Nauki

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