scholarly journals Photon-counting hexagonal pixel array CdTe detector: Spatial resolution characteristics for image-guided interventional applications

2016 ◽  
Vol 43 (5) ◽  
pp. 2118-2130 ◽  
Author(s):  
Srinivasan Vedantham ◽  
Suman Shrestha ◽  
Andrew Karellas ◽  
Linxi Shi ◽  
Matthew J. Gounis ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Photon Counting ◽  
Cdte Detector ◽  
Image Guided ◽  
Pixel Array

WE-G-204-03: Photon-Counting Hexagonal Pixel Array CdTe Detector: Optimal Resampling to Square Pixels

2015 ◽  
Vol 42 (6Part40) ◽  
pp. 3694-3694 ◽  
Author(s):  
S Shrestha ◽  
S Vedantham ◽  
A Karellas ◽  
R Bellazzini ◽  
G Spandre ◽  
...  
Keyword(s):  
Photon Counting ◽  
Cdte Detector ◽  
Pixel Array ◽  
Optimal Resampling

Measurements of charge sharing in a hybrid pixel photon counting CdTe detector

2021 ◽  
Vol 16 (12) ◽  
pp. C12027
Author(s):  
A. Krzyzanowska
Keyword(s):  
Spatial Resolution ◽  
Single Photon ◽  
Spectral Response ◽  
Photon Counting ◽  
Radiation Detectors ◽  
Charge Sharing ◽  
Single Photon Counting ◽  
X Ray ◽  
Cdte Detector ◽  
Wide Range

Abstract Hybrid pixel radiation detectors working in a single-photon counting mode have gained increasing attention due to their noiseless imaging and high dynamic range. Due to the fact that sensors of different materials can be attached to the readout circuit, they allow operation with a wide range of photon energies. The performance of the single photon counting detectors is limited by pile-up. To allow a detector to work under high flux conditions, the pixel size is reduced, which minimizes detector dead time. However, with smaller pixel sizes the charge sharing effect, a phenomenon that deteriorates both detection efficiency and spatial resolution is more profound. The influence of charge sharing on the detector performance can be quantified using parameterization of the s-curve obtained in the spectral response measurements. The article presents the measurements of the response function of a hybrid pixelated photon counting detector for certain primary energy, which corresponds to the probability of detecting a photon as a function of its energy deposition. The measurements were carried out using an X-ray tube by performing a threshold scan during illumination with X-ray photons of a 1.5 mm and 0.75 mm thick CdTe detector with 100 µm pixel pitch. The charge size cloud depends on the sensor material, the bias voltage, and the sensor thickness. Therefore, the experimental data from a sensor biased with different bias voltages are compared to the theoretical results based on a cascaded model of a single-photon counting segmented silicon detector. The study of the charge sharing influence on the spatial resolution of the CdTe detector will serve for a further study of the possible implementations of the algorithms achieving subpixel resolution, in which the charge sharing becomes the desired effect since the charge division in the pixels is used to interpolate the photon interaction position.

Evaluation and comparison of a CdTe based photon counting detector with an energy integrating detector for X-ray phase sensitive imaging of breast cancer

2021 ◽  
pp. 1-13
Author(s):  
Muhammad U. Ghani ◽  
Farid H. Omoumi ◽  
Xizeng Wu ◽  
Laurie L. Fajardo ◽  
Bin Zheng ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Spatial Resolution ◽  
Standard Dose ◽  
Photon Counting ◽  
High Energy ◽  
Edge Enhancement ◽  
X Ray ◽  
Photon Counting Detector ◽  
Phase Sensitive ◽  
Observer Studies

PURPOSE: To compare imaging performance of a cadmium telluride (CdTe) based photon counting detector (PCD) with a CMOS based energy integrating detector (EID) for potential phase sensitive imaging of breast cancer. METHODS: A high energy inline phase sensitive imaging prototype consisting of a microfocus X-ray source with geometric magnification of 2 was employed. The pixel pitch of the PCD was 55μm, while 50μm for EID. The spatial resolution was quantitatively and qualitatively assessed through modulation transfer function (MTF) and bar pattern images. The edge enhancement visibility was assessed by measuring edge enhancement index (EEI) using the acrylic edge acquired images. A contrast detail (CD) phantom was utilized to compare detectability of simulated tumors, while an American College of Radiology (ACR) accredited phantom for mammography was used to compare detection of simulated calcification clusters. A custom-built phantom was employed to compare detection of fibrous structures. The PCD images were acquired at equal, and 30% less mean glandular dose (MGD) levels as of EID images. Observer studies along with contrast to noise ratio (CNR) and signal to noise ratio (SNR) analyses were performed for comparison of two detection systems. RESULTS: MTF curves and bar pattern images revealed an improvement of about 40% in the cutoff resolution with the PCD. The excellent spatial resolution offered by PCD system complemented superior detection of the diffraction fringes at boundaries of the acrylic edge and resulted in an EEI value of 3.64 as compared to 1.44 produced with EID image. At MGD levels (standard dose), observer studies along with CNR and SNR analyses revealed a substantial improvement of PCD acquired images in detection of simulated tumors, calcification clusters, and fibrous structures. At 30% less MGD, PCD images preserved image quality to yield equivalent (slightly better) detection as compared to the standard dose EID images. CONCLUSION: CdTe-based PCDs are technically feasible to image breast abnormalities (low/high contrast structures) at low radiation dose levels using the high energy inline phase sensitive imaging technique.

High-speed UV imaging of elves and lightning from space: first simultaneous detections from the Mini-EUSO and ASIM instruments

2020 ◽  
Author(s):  
Matteo Battisti ◽  
Enrico Arnone ◽  
Mario Bertaina ◽  
Marco Casolino ◽  
Olivier Chanrion ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Speed ◽  
Multispectral Imaging ◽  
Gamma Ray ◽  
Single Photon ◽  
Uv Light ◽  
Photon Counting ◽  
Space Station ◽  
Wide Field ◽  
First Time

<p>The search for the physical mechanisms of lightning, transient luminous events and terrestrial gamma-ray flashes is receiving an extraordinary support by new space observations that have recently become available. Next to lightning detectors on geostationary satellites, new low orbit experiments are giving an unprecedented insight in the very source of these processes. Looking at the physics behind these new observations requires however to have a variety of different instruments covering the same event, and this is proving extremely challenging. Here, we present observations of UV emissions of elves and lightning taken for the first time simultaneously from the two instruments Mini-EUSO and ASIM operating on the international space station. Mini-EUSO was designed to perform observations of the UV-light night emission from Earth. It is a wide field of view telescope (44°x44° square FOV) installed for the first time on October 2019 inside the Zvezda Module of the ISS, looking nadir through a UV transparent window. Its optical system consists of two Fresnel lenses for light collection. The light is focused onto an array of 36 multi-anode photomultiplier tubes (MAPMT), for a total of 2304 pixels. Each pixel has a footprint on ground of ~5.5 km. The instrument is capable of single-photon counting on three different timescales: a 2.5 microsecond (D1) and a 320 microsecond (D2) timescale with a dedicated trigger system, and a 40.96ms timescale (D3) used to produce a continuous monitoring of the UV emission from the Earth. ASIM is an experiment dedicated to lightning and atmospheric processes. Its Modular Multispectral Imaging Array (MMIA) is made of an array of 3 high speed photometers probing different wavelength sampling at rates up to 100 kHz, and 2 Electron Multiplication Charge Coupled Devices (EM-CCDs) with a sub-km spatial resolution with an 80° FOV and recording up to 12 frames per second. Mini-EUSO detected several bright atmospheric events like lightning and elves, with a few km spatial resolution and different time resolutions, probing therefore different stages of the electromagnetic phenomena. Observations from Mini-EUSO were simultaneously captured by ASIM instruments, allowing for the first time to compare and complement the capabilities of the two instruments with a time inter-calibration based on unambiguous series of lightning detections.</p>

Centroiding algorithms and spatial resolution of photon counting detectors with cross-strip anodes

2003 ◽  
Author(s):  
Anton S. Tremsin ◽  
John V. Vallerga ◽  
Oswald H. W. Siegmund ◽  
Jeff S. Hull
Keyword(s):  
Spatial Resolution ◽  
Photon Counting ◽  
Photon Counting Detectors

scholarly journals The potential benefits of using higher X-ray energies for macromolecular crystallography

2019 ◽  
Vol 26 (4) ◽  
pp. 922-930 ◽  
Author(s):  
Joshua L. Dickerson ◽  
Elspeth F. Garman
Keyword(s):  
Photon Counting ◽  
Incident Beam ◽  
Macromolecular Crystallography ◽  
Silicon Detectors ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cdte Detector ◽  
Potential Benefits ◽  
Incident Beam Energy ◽  
First Time

Using X-ray energies higher than those normally used (5–15 keV) for macromolecular X-ray crystallography (MX) at synchrotron sources can theoretically increase the achievable signal as a function of dose and reduce the rate of radiation damage. In practice, a major stumbling block to the use of higher X-ray energy has been the reduced quantum efficiency of silicon detectors as the X-ray energy increases, but hybrid photon-counting CdTe detectors are optimized for higher X-ray energies, and their performance has been steadily improving. Here the potential advantages of using higher incident beam energy together with a CdTe detector for MX are explored, with a particular focus on the advantages that higher beam energies may have for MX experiments with microbeams or microcrystals. Monte Carlo simulations are presented here which for the first time include the efficiency responses of some available X-ray detectors, as well as the possible escape of photoelectrons from the sample and their entry from surrounding material. The results reveal a `sweet spot' at an incident X-ray energy of 26 keV, and show a greater than factor of two improvement in diffraction efficiency at this energy when using microbeams and microcrystals of 5 µm or less.

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