A new silicon avalanche photodiode photon counting detector module for astronomy

1990 ◽  
Vol 1 (6) ◽  
pp. 407-422 ◽  
Author(s):  
N. S. Nightingale
2020 ◽  
Vol 237 ◽  
pp. 07026
Author(s):  
Peng Ge ◽  
Cong Chen ◽  
Zhen Shang ◽  
Yanen Fan ◽  
Jingjing Guo ◽  
...  

Photon-counting detector array is very desired for high-resolution laser imaging based on direct time-of-flight measurement. Such systems have potential applications in remote sensing with long distances. We will perform three-dimensional imaging using a large InGaAs Geiger-mode avalanche photodiode array which has single-photon sensitivity. To improve the image quality with only a few photon detections, the photon counting imaging process is analyzed and a regularization method based on pixel spatial correlation is employed for image reconstruction. The performance of the method is compared with that of conventional maximum likelihood estimation on intensity and range image reconstructions of a building about six hundred meters away.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Petri Paakkari ◽  
Satu I. Inkinen ◽  
Miitu K. M. Honkanen ◽  
Mithilesh Prakash ◽  
Rubina Shaikh ◽  
...  

AbstractPhoton-counting detector computed tomography (PCD-CT) is a modern spectral imaging technique utilizing photon-counting detectors (PCDs). PCDs detect individual photons and classify them into fixed energy bins, thus enabling energy selective imaging, contrary to energy integrating detectors that detects and sums the total energy from all photons during acquisition. The structure and composition of the articular cartilage cannot be detected with native CT imaging but can be assessed using contrast-enhancement. Spectral imaging allows simultaneous decomposition of multiple contrast agents, which can be used to target and highlight discrete cartilage properties. Here we report, for the first time, the use of PCD-CT to quantify a cationic iodinated CA4+ (targeting proteoglycans) and a non-ionic gadolinium-based gadoteridol (reflecting water content) contrast agents inside human osteochondral tissue (n = 53). We performed PCD-CT scanning at diffusion equilibrium and compared the results against reference data of biomechanical and optical density measurements, and Mankin scoring. PCD-CT enables simultaneous quantification of the two contrast agent concentrations inside cartilage and the results correlate with the structural and functional reference parameters. With improved soft tissue contrast and assessment of proteoglycan and water contents, PCD-CT with the dual contrast agent method is of potential use for the detection and monitoring of osteoarthritis.


2020 ◽  
Vol 55 (4) ◽  
pp. 226-232
Author(s):  
Wei Zhou ◽  
Gregory J. Michalak ◽  
Jayse M. Weaver ◽  
Hao Gong ◽  
Lifeng Yu ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3081
Author(s):  
Xiaoli Sun ◽  
Daniel R. Cremons ◽  
Erwan Mazarico ◽  
Guangning Yang ◽  
James B. Abshire ◽  
...  

We report the development of a new type of space lidar specifically designed for missions to small planetary bodies for both topographic mapping and support of sample collection or landing. The instrument is designed to have a wide dynamic range with several operation modes for different mission phases. The laser transmitter consists of a fiber laser that is intensity modulated with a return-to-zero pseudo-noise (RZPN) code. The receiver detects the coded pulse-train by correlating the detected signal with the RZPN kernel. Unlike regular pseudo noise (PN) lidars, the RZPN kernel is set to zero outside laser firing windows, which removes most of the background noise over the receiver integration time. This technique enables the use of low peak-power but high pulse-rate lasers, such as fiber lasers, for long-distance ranging without aliasing. The laser power and the internal gain of the detector can both be adjusted to give a wide measurement dynamic range. The laser modulation code pattern can also be reconfigured in orbit to optimize measurements to different measurement environments. The receiver uses a multi-pixel linear mode photon-counting HgCdTe avalanche photodiode (APD) array with near quantum limited sensitivity at near to mid infrared wavelengths where many fiber lasers and diode lasers operate. The instrument is modular and versatile and can be built mostly with components developed by the optical communication industry.


2010 ◽  
Author(s):  
B. Dierickx ◽  
S. Bellis ◽  
N. Witvrouwen ◽  
B. Dupont ◽  
A. Defernez ◽  
...  

1993 ◽  
Vol 47 (5) ◽  
pp. 539-543 ◽  
Author(s):  
E. Neil Lewis ◽  
Patrick J. Treado ◽  
Ira W. Levin

A solid-state acousto-optic tunable filter (AOTF) is combined with krypton laser excitation (647 nm), holographic Raman filters, and photon-counting silicon avalanche photodiode (APD) detection to construct a miniaturized Raman spectrometer with no moving parts. The physically compact AOTF and the highly integrated APD provide a rugged, digitally controlled spectrometer of moderate spectral resolution and with a footprint comparable in size to a laboratory notebook. Instrument design details are considered and representative spectra are reported. Potential areas of application for this prototype Raman spectrometer are also discussed.


Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 848
Author(s):  
Matthias Wetzl ◽  
Evelyn Wenkel ◽  
Eva Balbach ◽  
Ebba Dethlefsen ◽  
Arndt Hartmann ◽  
...  

The primary objective of the study was to compare a spiral breast computed tomography system (SBCT) to digital breast tomosynthesis (DBT) for the detection of microcalcifications (MCs) in breast specimens. The secondary objective was to compare various reconstruction modes in SBCT. In total, 54 breast biopsy specimens were examined with mammography as a standard reference, with DBT, and with a dedicated SBCT containing a photon-counting detector. Three different reconstruction modes were applied for SBCT datasets (Recon1 = voxel size (0.15 mm)3, smooth kernel; Recon2 = voxel size (0.05 mm)3, smooth kernel; Recon3 = voxel size (0.05 mm)3, sharp kernel). Sensitivity and specificity of DBT and SBCT for the detection of suspicious MCs were analyzed, and the McNemar test was used for comparisons. Diagnostic confidence of the two readers (Likert Scale 1 = not confident; 5 = completely confident) was analyzed with ANOVA. Regarding detection of MCs, reader 1 had a higher sensitivity for DBT (94.3%) and Recon2 (94.9%) compared to Recon1 (88.5%; p < 0.05), while sensitivity for Recon3 was 92.4%. Respectively, reader 2 had a higher sensitivity for DBT (93.0%), Recon2 (92.4%), and Recon3 (93.0%) compared to Recon1 (86.0%; p < 0.05). Specificities ranged from 84.7–94.9% for both readers (p > 0.05). The diagnostic confidence of reader 1 was better with SBCT than with DBT (DBT 4.48 ± 0.88, Recon1 4.77 ± 0.66, Recon2 4.89 ± 0.44, and Recon3 4.75 ± 0.72; DBT vs. Recon1/2/3: p < 0.05), while reader 2 found no differences. Sensitivity and specificity for the detection of MCs in breast specimens is equal for DBT and SBCT when a small voxel size of (0.05 mm)3 is used with an equal or better diagnostic confidence for SBCT compared to DBT.


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