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Recent Progress in the Development of a-Se/CMOS Sensors for X-ray Detection. QUANTUM BEAM SCIENCE 2021. [DOI: 10.3390/qubs5040029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Amorphous selenium (a-Se) is a glass-former capable of deposition at high rates by thermal evaporation over a large area. It was chosen as a direct conversion material due to its appealing properties for imaging in both low and high X-ray energy ranges (<30 keV and <30 keV, respectively). It has a bandgap of 2.2 eV and can achieve high photodetection efficiency at short wavelengths less than 400 nm which makes it appealing for indirect conversion detectors. The integration of a-Se with readout integrated circuits started with thin-film transistors for digital flat panel X-ray detectors. With increasing applications in life science, biomedical imaging, X-ray imaging, high energy physics, and industrial imaging that require high spatial resolution, the integration of a-Se and CMOS is one direct way to improve the high-contrast visualization and high-frequency response. Over the past decade, significant improvements in a-Se/CMOS technologies have been achieved with improvements to modulation transfer function and detective quantum efficiency. We summarize recent advances in integrating and photon-counting detectors based on a-Se coupled with CMOS readout and discuss some of the shortcomings in the detector structure, such as low charge conversion efficiency at low electric field and high dark current at high electric field. Different pixel architectures and their performance will be highlighted.
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Ketelhut S, Büermann L, Hilgers G. Catalog of x-ray spectra of Mo-, Rh-, and W-anode-based x-ray tubes from 10 to 50 kV. Phys Med Biol 2021; 66. [PMID: 33902019 DOI: 10.1088/1361-6560/abfbb2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 04/26/2021] [Indexed: 11/11/2022]
Abstract
This work presents a comprehensive catalog of x-ray spectra measured from x-ray tubes with tungsten, molybdenum, and rhodium anodes generated at tube potentials between 10 and 50 kV in steps of 1 kV. They can serve as an input for dose calculations, image quality calculations, investigations of detector features, and validations of computational spectral models, among other things. The measurements are performed by means of a high-purity germanium detector-based spectrometer 1 m from the x-ray sources without any added filtration. The x-ray tubes are characterized by thin beryllium exit windows (0.15-4 mm); thus, for energies above 15 keV, the spectra recorded can be considered approximately unfiltered. This allows potential users of the catalog to computationally add any filter to the spectra in order to create special radiation qualities of their choice. To validate this option, a small number of spectra are recorded with filter materials in place whose purity and thickness are known with high precision. These spectra are compared to the corresponding spectra from the catalog obtained by means of computationally added filters. The two types of spectra agree extremely well. Several typical mammographic radiation qualities are selected to compare the spectra obtained from the catalog presented here with corresponding spectra obtained from other catalogs published by Booneet al(1997Med. Phys.241863-74) and Hernandezet al(2017Med. Phys.442148-60). In contrast to the work presented here, those spectra rely partly or fully on calculations. A quantitative comparison is made by means of typical x-ray quality descriptors such as the mean energy and the first and second half-value layer. The results obtained from the Boone catalog match those of the current catalog sufficiently well for the Mo- and Rh-anode-based spectra. However, significant differences up to 10 times the estimated uncertainties are found for the quality descriptors evaluated from the spectra of Hernandezet aland the W-anode based spectra of Booneet al.
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Affiliation(s)
| | - Ludwig Büermann
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Gerhard Hilgers
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
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Wang J, Chen L, Persson M, Rajbhandary PL, Kandlakunta P, Carini G, Fahrig R. Pulse pileup analysis for a double-sided silicon strip detector using variable pulse shapes. IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2019; 66:960-968. [PMID: 31327872 PMCID: PMC6640861 DOI: 10.1109/tns.2019.2917144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Due to pulse pileup, photon counting detectors (PCDs) suffer from count loss and energy distortion when operating in high count rate environments. In this paper, we studied the pulse pileup of a double-sided silicon strip detector (DSSSD) to evaluate its potential application in a mammography system. We analyzed the pulse pileup using pulses of varied shapes, where the shape of the pulse depends on the location of photon interaction within the detector. To obtain the shaped pulses, first, transient currents for photons interacting at different locations were simulated using a Technology Computer-Aided Design (TCAD) software. Next, the currents were shaped by a CR-RC2 shaping circuit, calculated using Simulink. After obtaining these pulses, both the different orders of pileup and the energy spectrum were calculated by taking into account the following two factors: 1) spatial distribution of photon interactions within the detector, and 2) time interval distribution between successive photons under a given photon flux. We found that for a DSSSD with thickness of 300 μm, pitch of 25 μm and strip length of 1 cm, under a bias voltage of 50 V, the variable pulse shape model predicts the fraction free of pileup can be > 90 % under a photon flux of 3.75 Mcps/mm2. The double-sided silicon-strip detector is a promising candidate for digital mammography applications.
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Affiliation(s)
- Jinghui Wang
- J. Wang was with the Department of Radiology, Stanford University, Stanford, CA 94305 USA. He is now with the Department of Radiation Oncology, Stanford University, Stanford, CA 94305 USA
| | - Linchuan Chen
- L. Chen was with the Department of Computer Science and Engineering, The Ohio State University, Columbus OH 43210 USA. He is now with Google, 1600 Amphitheatre Parkway, Mountain View, CA 94043 USA
| | - Mats Persson
- M. Persson is with the Department of Bioengineering, Stanford University, Stanford, California 94305 USA
| | - Paurakh L Rajbhandary
- P. L. Rajbhandary was with Department of Bioengineering, Stanford University, Stanford, CA 94305 USA
| | - Praneeth Kandlakunta
- P. Kandlakunta is with the Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 USA
| | - Gabriella Carini
- G. Carini was with the SLAC National Accelerator Laboratory, Menlo Park, CA 94025 USA. She is now with the Brookhaven National Laboratory, Upton, NY 11973 USA
| | - Rebecca Fahrig
- R. Fahrig was with the Department of Radiology, Stanford University, Stanford, CA 94305 USA. She is now with Siemens Healthcare GmbH, Erlangen, 91052 Germany, also with Pattern Recognition Lab, Friedrich-Alexander-University, Erlangen-Nuremberg, 91052 Germany
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Hong X, Zhou J, Ni S, Ma Y, Yao J, Zhou W, Liu Y, Wang M. Counting-loss correction for X-ray spectroscopy using unit impulse pulse shaping. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:505-513. [PMID: 29488930 DOI: 10.1107/s1600577518000322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/05/2018] [Indexed: 06/08/2023]
Abstract
High-precision measurement of X-ray spectra is affected by the statistical fluctuation of the X-ray beam under low-counting-rate conditions. It is also limited by counting loss resulting from the dead-time of the system and pile-up pulse effects, especially in a high-counting-rate environment. In this paper a detection system based on a FAST-SDD detector and a new kind of unit impulse pulse-shaping method is presented, for counting-loss correction in X-ray spectroscopy. The unit impulse pulse-shaping method is evolved by inverse deviation of the pulse from a reset-type preamplifier and a C-R shaper. It is applied to obtain the true incoming rate of the system based on a general fast-slow channel processing model. The pulses in the fast channel are shaped to unit impulse pulse shape which possesses small width and no undershoot. The counting rate in the fast channel is corrected by evaluating the dead-time of the fast channel before it is used to correct the counting loss in the slow channel.
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Affiliation(s)
- Xu Hong
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
| | - Jianbin Zhou
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
| | - Shijun Ni
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
| | - Yingjie Ma
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
| | - Jianfeng Yao
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
| | - Wei Zhou
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
| | - Yi Liu
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
| | - Min Wang
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, No.1 the Third Section East, Er Xianqiao Road, Chengdu, Sichuan 610059, People's Republic of China
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Liang AK, Koniczek M, Antonuk LE, El-Mohri Y, Zhao Q, Street RA, Lu JP. Performance of in-pixel circuits for photon counting arrays (PCAs) based on polycrystalline silicon TFTs. Phys Med Biol 2016; 61:1968-85. [PMID: 26878107 DOI: 10.1088/0031-9155/61/5/1968] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Photon counting arrays (PCAs), defined as pixelated imagers which measure the absorbed energy of x-ray photons individually and record this information digitally, are of increasing clinical interest. A number of PCA prototypes with a 1 mm pixel-to-pixel pitch have recently been fabricated with polycrystalline silicon (poly-Si)-a thin-film technology capable of creating monolithic imagers of a size commensurate with human anatomy. In this study, analog and digital simulation frameworks were developed to provide insight into the influence of individual poly-Si transistors on pixel circuit performance-information that is not readily available through empirical means. The simulation frameworks were used to characterize the circuit designs employed in the prototypes. The analog framework, which determines the noise produced by individual transistors, was used to estimate energy resolution, as well as to identify which transistors contribute the most noise. The digital framework, which analyzes how well circuits function in the presence of significant variations in transistor properties, was used to estimate how fast a circuit can produce an output (referred to as output count rate). In addition, an algorithm was developed and used to estimate the minimum pixel pitch that could be achieved for the pixel circuits of the current prototypes. The simulation frameworks predict that the analog component of the PCA prototypes could have energy resolution as low as 8.9% full width at half maximum (FWHM) at 70 keV; and the digital components should work well even in the presence of significant thin-film transistor (TFT) variations, with the fastest component having output count rates as high as 3 MHz. Finally, based on conceivable improvements in the underlying fabrication process, the algorithm predicts that the 1 mm pitch of the current PCA prototypes could be reduced significantly, potentially to between ~240 and 290 μm.
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Affiliation(s)
- Albert K Liang
- Department of Radiation Oncology, University of Michigan, Argus I Building, 519 W. William Street, Ann Arbor, MI 48109, USA
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X-ray tube spectra measurement and correction using a CdTe detector and an analytic response matrix for photon energies up to 160 keV. RADIAT MEAS 2016. [DOI: 10.1016/j.radmeas.2015.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abbene L, Gerardi G. High-rate dead-time corrections in a general purpose digital pulse processing system. JOURNAL OF SYNCHROTRON RADIATION 2015; 22:1190-201. [PMID: 26289270 PMCID: PMC4542454 DOI: 10.1107/s1600577515013776] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 07/20/2015] [Indexed: 05/09/2023]
Abstract
Dead-time losses are well recognized and studied drawbacks in counting and spectroscopic systems. In this work the abilities on dead-time correction of a real-time digital pulse processing (DPP) system for high-rate high-resolution radiation measurements are presented. The DPP system, through a fast and slow analysis of the output waveform from radiation detectors, is able to perform multi-parameter analysis (arrival time, pulse width, pulse height, pulse shape, etc.) at high input counting rates (ICRs), allowing accurate counting loss corrections even for variable or transient radiations. The fast analysis is used to obtain both the ICR and energy spectra with high throughput, while the slow analysis is used to obtain high-resolution energy spectra. A complete characterization of the counting capabilities, through both theoretical and experimental approaches, was performed. The dead-time modeling, the throughput curves, the experimental time-interval distributions (TIDs) and the counting uncertainty of the recorded events of both the fast and the slow channels, measured with a planar CdTe (cadmium telluride) detector, will be presented. The throughput formula of a series of two types of dead-times is also derived. The results of dead-time corrections, performed through different methods, will be reported and discussed, pointing out the error on ICR estimation and the simplicity of the procedure. Accurate ICR estimations (nonlinearity < 0.5%) were performed by using the time widths and the TIDs (using 10 ns time bin width) of the detected pulses up to 2.2 Mcps. The digital system allows, after a simple parameter setting, different and sophisticated procedures for dead-time correction, traditionally implemented in complex/dedicated systems and time-consuming set-ups.
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Affiliation(s)
- Leonardo Abbene
- Dipartimento di Fisica e Chimica, University of Palermo, Viale delle Scienze, Edificio 18, Palermo 90128, Italy
- Correspondence e-mail:
| | - Gaetano Gerardi
- Dipartimento di Fisica e Chimica, University of Palermo, Viale delle Scienze, Edificio 18, Palermo 90128, Italy
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Dwiecki K, Neunert G, Nogala-Kałucka M, Polewski K. Fluorescence quenching studies on the interaction of catechin-quinone with CdTe quantum dots. Mechanism elucidation and feasibility studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 149:523-530. [PMID: 25978020 DOI: 10.1016/j.saa.2015.04.100] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
Changes of the photoluminescent properties of QD in the presence of oxidized catechin (CQ) were investigated by absorption, steady-state fluorescence, fluorescence lifetime and dynamic light scattering measurements. Photoluminescence intensity and fluorescence lifetime was decreasing with increasing CQ concentration. Dynamic light scattering technique found the hydrodynamic diameter of QD suspension in water is in range of 45 nm, whereas in presence of CQ increased to mean values of 67 nm. Calculated from absorption peak position of excition band indicated on average QD size of 3.2 nm. Emission spectroscopy and time-resolved emission studies confirmed preservation of electronic band structure in QD-CQ aggregates. On basis of the presented results, the elucidated mechanism of QD fluorescence quenching is a result of the interaction between QD and CQ due to electron transfer and electrostatic attraction. The results of fluorescence quenching of water-soluble CdTe quantum dot (QD) capped with thiocarboxylic acid were used to implement a simple and fast method to determine the presence of native antioxidant quinones in aqueous solutions. Feasibility studies on this method carried out with oxidized catechin showed a linear relation between the QD emission and quencher concentration, in range from 1 up to 200 μM. The wide linear range of concentration dependence makes it possible to apply this method for the fast and sensitive detection of quinones in solutions.
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Affiliation(s)
- Krzysztof Dwiecki
- Poznan Life Sciences University, Department of Biotechnology and Food Analysis, 60-637 Poznan, ul. Mazowiecka 34, Poland
| | - Grażyna Neunert
- Poznan Life Sciences University, Department of Physics, 60-637 Poznan, ul. Wojska Polskiego 38/42, Poland
| | - Małgorzata Nogala-Kałucka
- Poznan Life Sciences University, Department of Biotechnology and Food Analysis, 60-637 Poznan, ul. Mazowiecka 34, Poland
| | - Krzysztof Polewski
- Poznan Life Sciences University, Department of Physics, 60-637 Poznan, ul. Wojska Polskiego 38/42, Poland.
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Tanguay J, Yun S, Kim HK, Cunningham IA. Detective quantum efficiency of photon-counting x-ray detectors. Med Phys 2015; 42:491-509. [DOI: 10.1118/1.4903503] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Sullivan SZ, Schmitt PD, Muir RD, DeWalt EL, Simpson GJ. Digital deconvolution filter derived from linear discriminant analysis and application for multiphoton fluorescence microscopy. Anal Chem 2014; 86:3508-16. [PMID: 24559143 PMCID: PMC3983021 DOI: 10.1021/ac404150d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
![]()
A digital filter derived from linear
discriminant analysis (LDA)
is developed for recovering impulse responses in photon counting from
a high speed photodetector (rise time of ∼1 ns) and applied
to remove ringing distortions from impedance mismatch in multiphoton
fluorescence microscopy. Training of the digital filter was achieved
by defining temporally coincident and noncoincident transients and
identifying the projection within filter-space that best separated
the two classes. Once trained, data analysis by digital filtering
can be performed quickly. Assessment of the reliability of the approach
was performed through comparisons of simulated voltage transients,
in which the ground truth results were known a priori. The LDA filter was also found to recover deconvolved impulses for
single photon counting from highly distorted ringing waveforms from
an impedance mismatched photomultiplier tube. The LDA filter was successful
in removing these ringing distortions from two-photon excited fluorescence
micrographs and through data simulations was found to extend the dynamic
range of photon counting by approximately 3 orders of magnitude through
minimization of detector paralysis.
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Affiliation(s)
- Shane Z Sullivan
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
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Abbene L, Gerardi G, Principato F, Sordo SD, Raso G. Direct measurement of mammographic X-ray spectra with a digital CdTe detection system. SENSORS (BASEL, SWITZERLAND) 2012; 12:8390-404. [PMID: 22969406 PMCID: PMC3436035 DOI: 10.3390/s120608390] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 11/16/2022]
Abstract
In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate X-ray spectroscopy in mammography (1-30 keV). The DPP system performs a height and shape analysis of the detector pulses, sampled and digitized by a 14-bit, 100 MHz ADC. We show the results of the characterization of the detection system both at low and high photon counting rates by using monoenergetic X-ray sources and a nonclinical X-ray tube. The detection system exhibits excellent performance up to 830 kcps with an energy resolution of 4.5% FWHM at 22.1 keV. Direct measurements of clinical molybdenum X-ray spectra were carried out by using a pinhole collimator and a custom alignment device. A comparison with the attenuation curves and the half value layer values, obtained from the measured and simulated spectra, from an ionization chamber and from a solid state dosimeter, also shows the accuracy of the measurements. These results make the proposed detection system a very attractive tool for both laboratory research, calibration of dosimeters and advanced quality controls in mammography.
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Affiliation(s)
- Leonardo Abbene
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
| | - Gaetano Gerardi
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
| | - Fabio Principato
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
| | - Stefano Del Sordo
- INAF/IASF Palermo, Via Ugo La Malfa 153, Palermo 90146, Italy; E-Mail:
| | - Giuseppe Raso
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
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