Clinical comparative study with a large-area amorphous silicon flat-panel detector: image quality and visibility of anatomic structures on chest radiography.

PubMed

Fink, Christian; Hallscheidt, Peter J; Noeldge, Gerd; Kampschulte, Annette; Radeleff, Boris; Hosch, Waldemar P; Kauffmann, Günter W; Hansmann, Jochen

2002-02-01

The objective of this study was to compare clinical chest radiographs of a large-area, flat-panel digital radiography system and a conventional film-screen radiography system. The comparison was based on an observer preference study of image quality and visibility of anatomic structures. Routine follow-up chest radiographs were obtained from 100 consecutive oncology patients using a large-area, amorphous silicon flat-panel detector digital radiography system (dose equivalent to a 400-speed film system). Hard-copy images were compared with previous examinations of the same individuals taken on a conventional film-screen system (200-speed). Patients were excluded if changes in the chest anatomy were detected or if the time interval between the examinations exceeded 1 year. Observer preference was evaluated for the image quality and the visibility of 15 anatomic structures using a five-point scale. Dose measurements with a chest phantom showed a dose reduction of approximately 50% with the digital radiography system compared with the film-screen radiography system. The image quality and the visibility of all but one anatomic structure of the images obtained with the digital flat-panel detector system were rated significantly superior (p < or = 0.0003) to those obtained with the conventional film-screen radiography system. The image quality and visibility of anatomic structures on the images obtained by the flat-panel detector system were perceived as equal or superior to the images from conventional film-screen chest radiography. This was true even though the radiation dose was reduced approximately 50% with the digital flat-panel detector system.

Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

NASA Astrophysics Data System (ADS)

Ravindran, V. R.; Sreelakshmi, C.; Vibin, Vibin

2008-09-01

The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ravindran, V. R.; Sreelakshmi, C.; Vibin

2008-09-26

The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CTmore » image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.« less

Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: visibility of simulated microcalcifications.

PubMed

Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C

2013-10-01

To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150-160, 160-180, and 180-200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200-212 and 212-224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224-250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160-180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat

A novel technique for ventriculoperitoneal shunting by flat panel detector CT-guided real-time fluoroscopy

PubMed Central

Kobayashi, Shinya; Ishikawa, Tatsuya; Mutoh, Tatsushi; Hikichi, Kentaro; Suzuki, Akifumi

2012-01-01

Background: Surgical placement of a ventriculoperitoneal shunt (VPS) is the main strategy to manage hydrocephalus. However, the failure rate associated with placement of ventricular catheters remains high. Methods: A hybrid operating room, equipped with a flat-panel detector digital subtraction angiography system containing C-arm cone-beam computed tomography (CB-CT) imaging, has recently been developed and utilized to assist neurosurgical procedures. We have developed a novel technique using intraoperative fluoroscopy and a C-arm CB-CT system to facilitate accurate placement of a VPS. Results: Using this novel technique, 39 consecutive ventricular catheters were placed accurately, and no ventricular catheter failures were experienced during the follow-up period. Only two patients experienced obstruction of the VPS, both of which occurred in the extracranial portion of the shunt system. Conclusion: Surgical placement of a VPS assisted by flat panel detector CT-guided real-time fluoroscopy enabled accurate placement of ventricular catheters and was associated with a decreased need for shunt revision. PMID:23226605

Development of 10B-Based 3He Replacement Neutron Detectors

NASA Astrophysics Data System (ADS)

King, Michael J.; Gozani, Tsahi; Hilliard, Donald B.

2011-12-01

Radiation portal monitors (RPM) are currently deployed at United States border crossings to passively inspect vehicles and persons for any emission of neutrons and/or gamma rays, which may indicate the presence of unshielded nuclear materials. The RPM module contains an organic scintillator with 3He proportional counters to detect gamma rays and thermalized neutrons, respectively. The supply of 3He is rapidly dwindling, requiring alternative detectors to provide the same function and performance. Our alternative approach is one consisting of a thinly-coated 10B flat-panel ionization chamber neutron detector that can be deployed as a direct drop-in replacement for current RPM 3He detectors. The uniqueness of our approach in providing a large-area detector is in the simplicity of construction, scalability of the unit cell detector, ease of adaptability to a variety of applications and low cost. Currently, Rapiscan Laboratories and Helicon Thin Film Systems have designed and developed an operational 100 cm2 multi-layer prototype 10BB-based ionization chamber.

TU-E-217BCD-06: Cone Beam Breast CT with a High Resolution Flat Panel Detector-Improvement of Calcification Visibility.

PubMed

Shen, Y; Zhong, Y; Lai, C; Wang, T; Shaw, C

2012-06-01

To investigate the advantage of a high resolution flat panel detector for improving the visibility of microcalcifications (MCs) in cone beam breast CT Methods: A paraffin cylinder was used to simulate a 100% adipose breast. Calcium carbonate grains, ranging from 125-140 μm to 224 - 250 μm in size, were used to simulate the MCs. Groups of 25 same size MCs were embedded at the phantom center. The phantom was scanned with a bench-top CBCT system at various exposure levels. A 75μm pitch flat panel detector (Dexela 2923, Perkin Elmer) with 500μm thick CsI scintillator plate was used as the high resolution detector. A 194 μm pitch detector (Paxscan 4030CB, Varian Medical Systems) was used for reference. 300 projection images were acquired over 360° and reconstructed. The images were reviewed by 6 readers. The MC visibility was quantified as the fraction of visible MCs and averaged for comparison. The visibility was plotted as a function of the estimated dose level for various MC sizes and detectors. The MTFs and DQEs were measured and compared. For imaging small (200 μm and smaller) MCs, the visibility achieved with the 75μm pitch detector was found to be significantly higher than those achieved with the 194μm pitch detector. For imaging larger MCs, there was little advantage in using the 75μm pitch detector. Using the 75μm pitch detector, MCs as small as 180 μm could be imaged to achieve a visibility of 78% with an isocenter tissue dose of ∼20 mGys versus 62% achieved with the 194 μm pitch detector at the same dose level. It was found that a high pitch flat panel detector had the advantages of extending its imaging capability to higher frequencies thus helping improve the visibility when used to image small MCs. This work was supported in part by grants CA104759, CA13852 and CA124585 from NIH-NCI, a grant EB00117 from NIH-NIBIB, and a subcontract from NIST-ATP. © 2012 American Association of Physicists in Medicine.

Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

PubMed Central

Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C.

2013-01-01

Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Methods: Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. Results: The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150–160, 160–180, and 180–200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200–212 and 212–224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224–250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160–180 μm MCs as compared to 28% visibility achieved by

Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen

2013-10-15

Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer).Methods: Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widelymore » used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used.Results: The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150–160, 160–180, and 180–200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200–212 and 212–224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224–250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160–180 μm MCs as compared to 28% visibility

Basic performance and stability of a CdTe solid-state detector panel.

PubMed

Tsuchiya, Katsutoshi; Takahashi, Isao; Kawaguchi, Tsuneaki; Yokoi, Kazuma; Morimoto, Yuuichi; Ishitsu, Takafumi; Suzuki, Atsurou; Ueno, Yuuichirou; Kobashi, Keiji

2010-05-01

We have developed a prototype gamma camera system (R1-M) using a cadmium telluride (CdTe) detector panel and evaluated the basic performance and the spectral stability. The CdTe panel consists of 5-mm-thick crystals. The field of view is 134 x 268 mm comprising 18,432 pixels with a pixel pitch of 1.4 mm. Replaceable small CdTe modules are mounted on to the circuit board by dedicated zero insertion force connectors. To make the readout circuit compact, the matrix read out is processed by dedicated ASICs. The panel is equipped with a cold-air cooling system. The temperature and humidity in the panel were kept at 20 degrees C and below 70% relative humidity. CdTe polarization was suppressed by the bias refresh technique to stabilize the detector. We also produced three dedicated square pixel-matched collimators: LEGP (20 mm-thick), LEHR (27 mm-thick), and LEUHR (35 mm-thick). We evaluated their basic performance (energy resolution, system resolution, and sensitivity) and the spectral stability in terms of short-term (several hours of continuous acquisition) and long-term (infrequent measurements over more than a year) activity. The intrinsic energy resolution (FWHM) acquired with Tc-99m (140.5 keV) was 6.6%. The spatial resolutions (FWHM at a distance of 100 mm) with LEGP, LEHR, and LEUHR collimators were 5.7, 4.9, and 4.2 mm, and the sensitivities were 71, 39, and 23 cps/MBq, respectively. The energy peak position and the intrinsic energy resolution after several hours of operation were nearly the same as the values a few minutes after the system was powered on; the variation of the peak position was <0.2%, and that of the resolution was about 0.3%. Infrequent measurements conducted over a year showed that the variations of the energy peak position and the intrinsic energy resolution of the system were at a similar level to those described above. The basic performance of the CdTe-gamma camera system was evaluated, and its stability was verified. It was shown that the

Cosmic Ray Detector

Science.gov Websites

A picture of our detector with the front panel removed. Normally the electronic board is located on the the front lucite panel. Below is a picture of a completed detector being held by Colleen Twitty

Development of a real-time digital radiography system using a scintillator-type flat-panel detector

NASA Astrophysics Data System (ADS)

Ikeda, Shigeyuki; Suzuki, Katsumi; Ishikawa, Ken; Okajima, Kenichi

2001-06-01

In order to study the advantage and remaining problems of FPD (flat panel detector) for clinical use by the real-time DR (digital radiography) system, we developed a prototype system using a scintillator type FPD and which was compared with previous I.I.-CCD type real-time DR. We replaced the X- ray detector of DR-2000X from I.I.-4M (4 million pixels)-CCD camera to the scintillator type dynamic FPD(7' X 9', 127 micrometers ), which can take both radiographic and fluoroscopic images. We obtained the images of head and stomach phantoms, and discussed about the image quality with medical doctors.

Performance analysis of a CsI-based flat panel detector in a cone beam variable resolution x-ray system

NASA Astrophysics Data System (ADS)

Dahi, Bahram; Keyes, Gary S.; Rendon, David A.; DiBianca, Frank A.

2007-03-01

A new Cone-Beam CT (CBCT) system is introduced that uses the concept of Variable Resolution X-ray (VRX) detection, which has previously been demonstrated to significantly increase spatial resolution for small objects. An amorphous silicon Flat Panel Detector (FPD) with a CsI scintillator (PaxScan 2020, Varian, Salt Lake City, UT) is coupled with a micro-focus x-ray tube (35 - 80 kVp, 10 - 250 μA) to form a CBCT. The FPD is installed on a rotating arm that can be adjusted to any angle θ, called the VRX angle, between 90° and 0° with respect to the x-ray direction. A VRX angle of 90° for the detector corresponds to a conventional CBCT whereas a VRX angle of 30° means that the detector is tilted 90° - 30° = 60° from its perpendicular position. Tilting the FPD in this manner reduces both the line-spread function width and the sampling distance by a factor of sin(θ), thereby increasing detector spatial resolution proportionately. An in-house phantom is used to measure the MTF of the reconstructed CT images using different VRX angles. An increase by a factor of 1.67 +/- 0.007 is observed in the MTF cutoff frequency at 30° compared to 90° in images acquired at 75 kVp. Expected theoretical value for this case is 2.0. The new Cone-Beam Variable Resolution X-ray (CB-VRX) CT system is expected to significantly improve the images acquired from small objects - such as small animals - while exploiting the opportunities offered by a conventional CBCT.

Ultra-thin plasma panel radiation detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedman, Peter S.

An ultra-thin radiation detector includes a radiation detector gas chamber having at least one ultra-thin chamber window and an ultra-thin first substrate contained within the gas chamber. The detector further includes a second substrate generally parallel to and coupled to the first substrate and defining a gas gap between the first substrate and the second substrate. The detector further includes a discharge gas between the substrates and contained within the gas chamber, where the discharge gas is free to circulate within the gas chamber and between the first and second substrates at a given gas pressure. The detector further includesmore » a first electrode coupled to one of the substrates and a second electrode electrically coupled to the first electrode. The detector further includes a first discharge event detector coupled to at least one of the electrodes for detecting a gas discharge counting event in the electrode.« less

Attic Retrofits Using Nail-Base Insulated Panels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mallay, David; Kochkin, Vladimir

This project developed and demonstrated a roof/attic energy retrofit solution using nail-base insulated panels for existing homes where traditional attic insulation approaches are not effective or feasible. Nail-base insulated panels (retrofit panels) consist of rigid foam insulation laminated to one face of a wood structural panel. The prefabricated panels are installed above the existing roof deck during a reroofing effort.

High efficiency proportional neutron detector with solid liner internal structures

DOEpatents

Kisner, Roger Allen; Holcomb, David Eugene; Brown, Gilbert M.

2014-08-05

A tube-style neutron detector, a panel-style neutron detector incorporating a plurality of tube-style neutron detectors, and a panel-style neutron detector including a plurality of anode wires are provided. A plurality of channels is provided in a neutron detector such that each channel has an inner surface of a coating layer including a neutron-absorbing material. A wire anode is provided at end of each channel so that electrons generated by a charged daughter particle generated by a neutron are collected to detect a neutron-matter interaction. Moderator units can be incorporated into a neutron detector to provide improved detection efficiencies and/or to determine neutron energy spectrum. Gas-based proportional response from the neutron detectors can be employed for special nuclear material (SNM) detection. This neutron detector can provide similar performance to .sup.3He-based detectors without requiring .sup.3He and without containing toxic, flammable, or high-pressure materials.

[Change in process management by implementing RIS, PACS and flat-panel detectors].

PubMed

Imhof, H; Dirisamer, A; Fischer, H; Grampp, S; Heiner, L; Kaderk, M; Krestan, C; Kainberger, F

2002-05-01

Implementation of radiological information systems (RIS) and picture archiving and communicating systems (PACS) results in significant changes of workflow in a radiological department. Additional connection with flat-panel detectors leads to a shortening of the work process. RIS and PACS implementation alone reduces the complete workflow by 21-80%. With flatpanel technology the image production process is further shortened by 25-30%. The workflow-steps are changed from original 17-12 with the implementation of RIS and PACS and to 5 with the integrated use of flatpanels. This clearly recognizable advantages in the workflow need an according financial investment. Several studies could show that the capitalisation-factor calculated over eight years is positive, with a gain range between 5-25%. Whether the additional implementation of flatpanel detectors results also in a positive capitalisation over the years, cannot be estimated exactly, at the moment, because the experiences are too short. Particularly critical are the interfaces, which needs a constant quality control. Our flatpanel detector-system is fixed, special images--as we have them in about 3-5% of all cases--need still conventional filmscreen or phosphorplate-systems. Full-spine and long-leg examinations cannot be performed with sufficient exactness. Without any questions implementation of integrated RIS, PACS and flatpanel detector-system needs excellent training of the employees, because of the changes in workflow etc. The main profits of such an integrated implementation are an increase in quality in image and report datas, easier handling--there are almost no more cassettes necessary--and excessive shortening of workflow.

Technical Note: A Feasibility Study of Using the Flat Panel Detector on Linac for the kV X-ray Generator Test.

PubMed

Cai, Bin; Dolly, Steven; Kamal, Gregory; Yaddanapudi, Sridhar; Sun, Baozhou; Goddu, S Murty; Mutic, Sasa; Li, Hua

2018-04-28

To investigate the feasibility of using kV flat panel detector on linac for consistency evaluations of kV X-ray generator performance. An in-house designed aluminum (Al) array phantom with six 9×9 cm 2 square regions having various thickness was proposed and used in this study. Through XML script-driven image acquisition, kV images with various acquisition settings were obtained using the kV flat panel detector. Utilizing pre-established baseline curves, the consistency of X-ray tube output characteristics including tube voltage accuracy, exposure accuracy and exposure linearity were assessed through image quality assessment metrics including ROI mean intensity, ROI standard deviation (SD) and noise power spectrums (NPS). The robustness of this method was tested on two linacs for a three-month period. With the proposed method, tube voltage accuracy can be verified through conscience check with a 2% tolerance and 2 kVp intervals for forty different kVp settings. The exposure accuracy can be tested with a 4% consistency tolerance for three mAs settings over forty kVp settings. The exposure linearity tested with three mAs settings achieved a coefficient of variation (CV) of 0.1. We proposed a novel approach that uses the kV flat panel detector available on linac for X-ray generator test. This approach eliminates the inefficiencies and variability associated with using third party QA detectors while enabling an automated process. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Source strength verification and quality assurance of preloaded brachytherapy needles using a CMOS flat panel detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golshan, Maryam, E-mail: maryam.golshan@bccancer.bc.ca; Spadinger, Ingrid; Chng, Nick

2016-06-15

Purpose: Current methods of low dose rate brachytherapy source strength verification for sources preloaded into needles consist of either assaying a small number of seeds from a separate sample belonging to the same lot used to load the needles or performing batch assays of a subset of the preloaded seed trains. Both of these methods are cumbersome and have the limitations inherent to sampling. The purpose of this work was to investigate an alternative approach that uses an image-based, autoradiographic system capable of the rapid and complete assay of all sources without compromising sterility. Methods: The system consists of amore » flat panel image detector, an autoclavable needle holder, and software to analyze the detected signals. The needle holder was designed to maintain a fixed vertical spacing between the needles and the image detector, and to collimate the emissions from each seed. It also provides a sterile barrier between the needles and the imager. The image detector has a sufficiently large image capture area to allow several needles to be analyzed simultaneously.Several tests were performed to assess the accuracy and reproducibility of source strengths obtained using this system. Three different seed models (Oncura 6711 and 9011 {sup 125}I seeds, and IsoAid Advantage {sup 103}Pd seeds) were used in the evaluations. Seeds were loaded into trains with at least 1 cm spacing. Results: Using our system, it was possible to obtain linear calibration curves with coverage factor k = 1 prediction intervals of less than ±2% near the centre of their range for the three source models. The uncertainty budget calculated from a combination of type A and type B estimates of potential sources of error was somewhat larger, yielding (k = 1) combined uncertainties for individual seed readings of 6.2% for {sup 125}I 6711 seeds, 4.7% for {sup 125}I 9011 seeds, and 11.0% for Advantage {sup 103}Pd seeds. Conclusions: This study showed that a flat panel detector dosimetry

Aging of imaging properties of a CMOS flat-panel detector for dental cone-beam computed tomography

NASA Astrophysics Data System (ADS)

Kim, D. W.; Han, J. C.; Yun, S.; Kim, H. K.

2017-01-01

We have experimentally investigated the long-term stability of imaging properties of a flat-panel detector in conditions used for dental x-ray imaging. The detector consists of a CsI:Tl layer and CMOS photodiode pixel arrays. Aging simulations were carried out using an 80-kVp x-ray beam at an air-kerma rate of approximately 5 mGy s-1 at the entrance surface of the detector with a total air kerma of up to 0.6 kGy. Dark and flood-field images were periodically obtained during irradiation, and the mean signal and noise levels were evaluated for each image. We also evaluated the modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). The aging simulation showed a decrease in both the signal and noise of the gain-offset-corrected images, but there was negligible change in the signal-to-noise performance as a function of the accumulated dose. The gain-offset correction for analyzing images resulted in negligible changes in MTF, NPS, and DQE results over the total dose. Continuous x-ray exposure to a detector can cause degradation in the physical performance factors such the detector sensitivity, but linear analysis of the gain-offset-corrected images can assure integrity of the imaging properties of a detector during its lifetime.

Quantitative comparison using Generalized Relative Object Detectability (G-ROD) metrics of an amorphous selenium detector with high resolution Microangiographic Fluoroscopes (MAF) and standard flat panel detectors (FPD).

PubMed

Russ, M; Shankar, A; Jain, A; Setlur Nagesh, S V; Ionita, C N; Scott, C; Karim, K S; Bednarek, D R; Rudin, S

2016-02-27

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25 μ m pixel pitch, and 1000 μ m thick a-Se layer operating at 10V/ μ m bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-prewhitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal-spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide breakthrough abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices.

Reliability and validity of soft copy images based on flat-panel detector in pneumoconiosis classification: comparison with the analog radiographs.

PubMed

Lee, Won-Jeong; Choi, Byung-Soon

2013-06-01

The aim of this study was to evaluate the reliability and validity of soft copy images based on flat-panel detector of digital radiography (DR-FPD soft copy images) compared to analog radiographs (ARs) in pneumoconiosis classification and diagnosis. DR-FPD soft copy images and ARs from 349 subjects were independently read by four-experienced readers according to the International Labor Organization 2000 guidelines. DR-FPD soft copy images were used to obtain consensus reading (CR) by all readers as the gold standard. Reliability and validity were evaluated by a κ and receiver operating characteristic analysis, respectively. In small opacity, overall interreader agreement of DR-FPD soft copy images was significantly higher than that of ARs, but it was not significantly different in large opacity and costophrenic angle obliteration. In small opacity, agreement of DR-FPD soft copy images with CR was significantly higher than that of ARs with CR. It was also higher than that of ARs with CR in pleural plaque and thickening. Receiver operating characteristic areas were not different significantly between DR-FPD soft copy images and ARs. DR-FPD soft copy images showed accurate and reliable results in pneumoconiosis classification and diagnosis compared to ARs. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

Quantitative comparison using generalized relative object detectability (G-ROD) metrics of an amorphous selenium detector with high resolution microangiographic fluoroscopes (MAF) and standard flat panel detectors (FPD)

NASA Astrophysics Data System (ADS)

Russ, M.; Shankar, A.; Jain, A.; Setlur Nagesh, S. V.; Ionita, C. N.; Scott, C.; Karim, K. S.; Bednarek, D. R.; Rudin, S.

2016-03-01

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25μm pixel pitch, and 1000μm thick a-Se layer operating at 10V/μm bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-pre-whitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal- spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide break- through abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices.

Quantitative comparison using Generalized Relative Object Detectability (G-ROD) metrics of an amorphous selenium detector with high resolution Microangiographic Fluoroscopes (MAF) and standard flat panel detectors (FPD)

PubMed Central

Russ, M.; Shankar, A.; Jain, A.; Setlur Nagesh, S. V.; Ionita, C. N.; Scott, C.; Karim, K. S.; Bednarek, D. R.; Rudin, S.

2017-01-01

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25μm pixel pitch, and 1000μm thick a-Se layer operating at 10V/μm bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-prewhitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal-spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide breakthrough abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices. PMID:28615795

Performance of mobile digital X-ray fluoroscopy using a novel flat panel detector for intraoperative use.

PubMed

Jeong, Chang-Won; Ryu, Jong-Hyun; Joo, Su-Chong; Jun, Hong-Young; Heo, Dong-Woon; Lee, Jinseok; Kim, Kyong-Woo; Yoon, Kwon-Ha

2015-01-01

Technologies employing digital X-ray devices are developed for mobile settings. To develop a mobile digital X-ray fluoroscopy (MDF) for intraoperative guidance, using a novel flat panel detector to focus on diagnostics in outpatient clinics, operating and emergency rooms. An MDF for small-scale field diagnostics was configured using an X-ray source and a novel flat panel detector. The imager enabled frame rates reaching 30 fps in full resolution fluoroscopy with maximal running time of 5 minutes. Signal-to-noise (SNR), contrast-to-noise (CNR), and spatial resolution were analyzed. Stray radiation, exposure radiation dose, and effective absorption dose were measured for patients. The system was suitable for small-scale field diagnostics. SNR and CNR were 62.4 and 72.0. Performance at 10% of MTF was 9.6 lp/mm (53 μ m) in the no binned mode. Stray radiation at 100 cm and 150 cm from the source was below 0.2 μ Gy and 0.1 μ Gy. Exposure radiation in radiography and fluoroscopy (5 min) was 10.2 μ Gy and 82.6 mGy. The effective doses during 5-min-long fluoroscopy were 0.26 mSv (wrist), 0.28 mSv (elbow), 0.29 mSv (ankle), and 0.31 mSv (knee). The proposed MDF is suitable for imaging in operating rooms.

Smile effect detection for dispersive hypersepctral imager based on the doped reflectance panel

NASA Astrophysics Data System (ADS)

Zhou, Jiankang; Liu, Xiaoli; Ji, Yiqun; Chen, Yuheng; Shen, Weimin

2012-11-01

Hyperspectral imager is now widely used in many regions, such as resource development, environmental monitoring and so on. The reliability of spectral data is based on the instrument calibration. The smile, wavelengths at the center pixels of imaging spectrometer detector array are different from the marginal pixels, is a main factor in the spectral calibration because it can deteriorate the spectral data accuracy. When the spectral resolution is high, little smile can result in obvious signal deviation near weak atmospheric absorption peak. The traditional method of detecting smile is monochromator wavelength scanning which is time consuming and complex and can not be used in the field or at the flying platform. We present a new smile detection method based on the holmium oxide panel which has the rich of absorbed spectral features. The higher spectral resolution spectrometer and the under-test imaging spectrometer acquired the optical signal from the Spectralon panel and the holmium oxide panel respectively. The wavelength absorption peak positions of column pixels are determined by curve fitting method which includes spectral response function sequence model and spectral resampling. The iteration strategy and Pearson coefficient together are used to confirm the correlation between the measured and modeled spectral curve. The present smile detection method is posed on our designed imaging spectrometer and the result shows that it can satisfy precise smile detection requirement of high spectral resolution imaging spectrometer.

Extra-oral dental radiography for disaster victims using a flat panel X-ray detector and a hand-held X-ray generator.

PubMed

Ohtani, M; Oshima, T; Mimasaka, S

2017-12-01

Forensic odontologists commonly incise the skin for post-mortem dental examinations when it is difficult to open the victim's mouth. However, it is prohibited by law to incise dead bodies without permission in Japan. Therefore, we attempted using extra-oral dental radiography, using a digital X-ray equipment with rechargeable batteries, to overcome this restriction. A phantom was placed in the prone position on a table, and three plain dental radiographs were used per case: "lateral oblique radiographs" for left and right posterior teeth and a "contact radiograph" for anterior teeth were taken using a flat panel X-ray detector and a hand-held X-ray generator. The resolving power of the images was measured by a resolution test chart, and the scattered X-ray dose was measured using an ionization chamber-type survey meter. The resolving power of the flat panel X-ray detector was 3.0 lp/mm, which was less than that of intra-oral dental methods, but the three extra-oral plain dental radiographs provided the overall dental information from outside of the mouth, and this approach was less time-consuming. In addition, the higher dose of scattered X-rays was laterally distributed, but the dose per case was much less than that of intra-oral dental radiographs. Extra-oral plain dental radiography can be used for disaster victim identification by dental methods even when it is difficult to open the mouth. Portable and rechargeable devices, such as a flat panel X-ray detector and a hand-held X-ray generator, are convenient to bring and use anywhere, even at a disaster scene lacking electricity and water.

X-ray light valve (XLV): a novel detectors' technology for digital mammography

NASA Astrophysics Data System (ADS)

Marcovici, Sorin; Sukhovatkin, Vlad; Oakham, Peter

2014-03-01

A novel method, based on X-ray Light Valve (XLV) technology, is proposed for making good image quality yet inexpensive flat panel detectors for digital mammography. The digital mammography markets, particularly in the developing countries, demand quality machines at substantially lower prices than the ones available today. Continuous pressure is applied on x-ray detectors' manufacturers to reduce the flat panel detectors' prices. XLV presents a unique opportunity to achieve the needed price - performance characteristics for direct conversion, x-ray detectors. The XLV based detectors combine the proven, superior, spatial resolution of a-Se with the simplicity and low cost of liquid crystals and optical scanning. The x-ray quanta absorbed by a 200 μm a-Se produce electron - hole pairs that move under an electric field to the top and bottom of a-Se layer. This 2D charge distribution creates at the interface with the liquid crystals a continuous (analog) charge image corresponding to the impinging radiation's information. Under the influence of local electrical charges next to them, the liquid crystals twist proportionally to the charges and vary their light reflectivity. A scanning light source illuminates the liquid crystals while an associated, pixilated photo-detector, having a 42 μm pixel size, captures the light reflected by the liquid crystals and converts it in16 bit words that are transmitted to the machine for image processing and display. The paper will describe a novel XLV, 25 cm x 30 cm, flat panel detector structure and its underlying physics as well as its preliminary performance measured on several engineering prototypes. In particular, the paper will present the results of measuring XLV detectors' DQE, MTF, dynamic range, low contrast resolution and dynamic behavior. Finally, the paper will introduce the new, low cost, XLV detector based, digital mammography machine under development at XLV Diagnostics Inc.

Wood-based panels : supply, trade and consumption

Treesearch

Henry Spelter

2000-01-01

Preliminary figures of wood-based panels consumption in Europe show a small increase in 1999 to 52.1 million m3 a new record level. However, according to the European Panel Federation (EPF), real consumption taking into account particle board stock changes, was higher due to the recovery of markets in the second half of 1999. Particle board is the main panel in Europe...

Composite panels based on woven sandwich-fabric preforms

NASA Astrophysics Data System (ADS)

van Vuure, Aart Willem

A new type of sandwich material was investigated, based on woven sandwich-fabric preforms. Because of the integrally woven nature of the sandwich-fabric the skin-core debonding resistance of panels and structures based on the preform is very high. As the sandwich-fabrics are produced by a large scale textile weaving process (velvet weaving or distance weaving) and already a preform of a sandwich is available, the cost of the final panel or structure can potentially stay limited. Most attention in this work is focussed on the mechanical performance of sandwich-fabric panels. The high skin-core debonding resistance was verified and also indications were found of a good damage tolerance. Both unfoamed and foamed panels were evaluated and compared with existing sandwich panels. Microstructural parameters investigated for unfoamed cores are pile length, pile density, woven pile angles, degree of pile stretching, tilt angles of the piles induced during panel production and resin content and distribution. For foamed panels it is especially the foam density which has an important influence. There appears to be a synergistic effect between piles and foam in the sandwich core, leading to very acceptable mechanical properties. For panels for (semi) structural applications, foaming is almost indispensable once the panel thickness is higher than about 15 mm. To understand the behaviour of foamed panels, attention was paid to the modelling of the mechanics of pure foam. The foam microstructure was modelled with the model of an anisotropic tetrakaidecahedron. The mechanical properties of unfoamed panels were modelled with the help of finite elements. A detailed geometrical description of the core layout was made which was incorporated into a preprocessing program for a finite element code. Attention is paid to the production of panels based on the woven preforms. A newly developed Adhesive Foil Stretching process was investigated. Also the foaming of panels was studied. A lot of

SU-E-I-25: Performance Evaluation of a Proposed CMOS-Based X-Ray Detector Using Linear Cascade Model Analysis.

PubMed

Jain, A; Bednarek, D; Rudin, S

2012-06-01

The need for high-resolution, dynamic x-ray imaging capability for neurovascular applications has put an ever increasing demand on x-ray detector technology. Present state-of-the-art detectors such as flat panels have limited resolution and noise performance. A linear cascade model analysis was used to estimate the theoretical performance for a proposed CMOS-based detector. The proposed CMOS-based detector was assumed to have a 300-micron thick HL type CsI phosphor, 35-micron pixels, a variable gain light image intensifier (LU), and 400 electron readout noise. The proposed detector has a CMOS sensor coupled to an LII which views the output of the CsI phosphor. For the analysis the whole imaging chain was divided into individual stages characterized by one of the basic processes (stochastic/deterministic blurring, binomial selection, quantum gain, additive noise). Standard linear cascade modeling was used for the propagation of signal and noise through the stages and an RQA5 spectrum was assumed. The gain, blurring or transmission of different stages was either measured or taken from manufacturer's specifications. The theoretically calculated MTF and DQE for the proposed detector were compared with a high-resolution, high-sensitive Micro-Angio Fluoroscope (MAF), predecessor of the proposed detector. Signal and noise for each of the 19 stages in the complete imaging chain were calculated and showed improved performance. For example, at 5 cycles/mm the MTF and DQE were 0.08 and 0.28, respectively, for the CMOS detector compared to 0.05 and 0.07 for the MAF detector. The proposed detector will have improved MTF and DQE and slimmer physical dimension due to the elimination of the large fiber-optic taper used in the MAF. Once operational, the proposed CMOS detector will serve as a further improvement over standard flat panel detectors compared to the MAF which is already receiving a very positive reception by neuro-vascular interventionalists. (Support:NIH-Grant R01EB

Performance evaluation of a retrofit digital detector-based mammography system.

PubMed

Marshall, Nicholas W; van Ongeval, Chantal; Bosmans, Hilde

2016-02-01

A retrofit flat panel detector was integrated with a GE DMR+ analog mammography system and characterized using detective quantum efficiency (DQE). Technical system performance was evaluated using the European Guidelines protocol, followed by a limited evaluation of clinical image quality for 20 cases using image quality criteria in the European Guidelines. Optimal anode/filter selections were established using signal difference-to-noise ratio measurements. Only small differences in peak DQE were seen between the three anode/filter settings, with an average value of 0.53. For poly(methyl methacrylate) (PMMA) thicknesses above 60 mm, the Rh/Rh setting was the optimal anode/filter setting. The system required a mean glandular dose of 0.54 mGy at 30 kV Rh/Rh to reach the Acceptable gold thickness limit for 0.1 mm details. Imaging performance of the retrofit unit with the GE DMR+ is notably better than of powder based computed radiography systems and is comparable to current flat panel FFDM systems. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

[Flat-panel detector technology -State-of-the-art and future prospects-].

PubMed

Yamazaki, Tatsuya

2002-01-01

A flat-panel detector (FPD) is a long-awaited technology to implement the digital X-ray imaging technology into the radiological department. This paper describes the state-of-the-art technology and future prospects on the FPD technology. State-of-the-art technology was reviewed taking the CXDI series as an example. Several FPD-based systems have been introduced into the Japanese market since CXDI-11 opened it in November 1998. Accompanying CXDI-C2 for control, CXDI-22 for table position and CXDI-31 for portable, the CXDI series fulfills the requirement of the radiography room being a fully digitalized room. The FPD on the CXDI series is comprised of a scintillator (Gd(2)O(2)S:Tb(3+)) as a primary sensor in which the X-ray is captured and an amorphous silicon detector (LANMIT) as a secondary sensor in which the fluorescent light is detected. Since the scintillator is identical to that of the screen-film systems, it can be said as proven, durable and chemically stable and it is expected to produce the same image quality as the screen-film systems. CXDI-31, a portable FPD-based system, was developed targeting thinner dimensions, lightweight, durability and high spatial resolution. Thoroughly re-designing the mechanical structure and reducing the power consumption at the readout IC realized thinner dimensions. Introducing the portable note PC technologies successfully combined lightweight with durability. Improving the sensor process and re-designing the layout made the sensor high resolution without compromising the signal-to-noise ratio. Future prospects were overviewed in the aspect of technology and applications. Sensitivity, spatial resolution, frame rate and portability were described as the upcoming technology. Increasing gain and reducing noise will realize higher sensitivity, especially by adopting the PbI(2), HgI(2) or such photoconductor materials as the primary sensor. Pixelized amplifier will also achieve higher sensitivity. Layered sensor designed such

Cervical soft tissue imaging using a mobile CBCT scanner with a flat panel detector in comparison with corresponding CT and MRI data sets.

PubMed

Heiland, Max; Pohlenz, Philipp; Blessmann, Marco; Habermann, Christian R; Oesterhelweg, Lars; Begemann, Philipp C; Schmidgunst, Christian; Blake, Felix A S; Püschel, Klaus; Schmelzle, Rainer; Schulze, Dirk

2007-12-01

The aim of this study was to evaluate soft tissue image quality of a mobile cone-beam computed tomography (CBCT) scanner with an integrated flat-panel detector. Eight fresh human cadavers were used in this study. For evaluation of soft tissue visualization, CBCT data sets and corresponding computed tomography (CT) and magnetic resonance imaging (MRI) data sets were acquired. Evaluation was performed with the help of 10 defined cervical anatomical structures. The statistical analysis of the scoring results of 3 examiners revealed the CBCT images to be of inferior quality regarding the visualization of most of the predefined structures. Visualization without a significant difference was found regarding the demarcation of the vertebral bodies and the pyramidal cartilages, the arteriosclerosis of the carotids (compared with CT), and the laryngeal skeleton (compared with MRI). Regarding arteriosclerosis of the carotids compared with MRI, CBCT proved to be superior. The integration of a flat-panel detector improves soft tissue visualization using a mobile CBCT scanner.

Large area x-ray detectors for cargo radiography

NASA Astrophysics Data System (ADS)

Bueno, C.; Albagli, D.; Bendahan, J.; Castleberry, D.; Gordon, C.; Hopkins, F.; Ross, W.

2007-04-01

Large area x-ray detectors based on phosphors coupled to flat panel amorphous silicon diode technology offer significant advances for cargo radiologic imaging. Flat panel area detectors provide large object coverage offering high throughput inspections to meet the high flow rate of container commerce. These detectors provide excellent spatial resolution when needed, and enhanced SNR through low noise electronics. If the resolution is reduced through pixel binning, further advances in SNR are achievable. Extended exposure imaging and frame averaging enables improved x-ray penetration of ultra-thick objects, or "select-your-own" contrast sensitivity at a rate many times faster than LDAs. The areal coverage of flat panel technology provides inherent volumetric imaging with the appropriate scanning methods. Flat panel area detectors have flexible designs in terms of electronic control, scintillator selection, pixel pitch, and frame rates. Their cost is becoming more competitive as production ramps up for the healthcare, nondestructive testing (NDT), and homeland protection industries. Typically used medical and industrial polycrystalline phosphor materials such as Gd2O2S:Tb (GOS) can be applied to megavolt applications if the phosphor layer is sufficiently thick to enhance x-ray absorption, and if a metal radiator is used to augment the quantum detection efficiency and reduce x-ray scatter. Phosphor layers ranging from 0.2-mm to 1-mm can be "sandwiched" between amorphous silicon flat panel diode arrays and metal radiators. Metal plates consisting of W, Pb or Cu, with thicknesses ranging from 0.25-mm to well over 1-mm can be used by covering the entire area of the phosphor plate. In some combinations of high density metal and phosphor layers, the metal plate provides an intensification of 25% in signal due to electron emission from the plate and subsequent excitation within the phosphor material. This further improves the SNR of the system.

Operational performance characteristics of the WISH detector array on the ISIS spallation neutron source

NASA Astrophysics Data System (ADS)

Duxbury, D.; Khalyavin, D.; Manuel, P.; Raspino, D.; Rhodes, N.; Schooneveld, E.; Spill, E.

2014-12-01

The performance of the position sensitive neutron detector array of the WISH diffractometer is discussed. WISH (Wide angle In a Single Histogram) is one of the seven instruments currently available for users on the second target station (TS2) of the ISIS spallation neutron source, and is used mainly for magnetic studies of materials. WISH is instrumented with an array of 10 detector panels, covering an angular range of 320o, orientated in two semi-cylindrical annuli around a central sample position at a radius of 2.2m. In total the 10 detector panels are composed of 1520 3He based position sensitive detector tubes. Each tube has an active length of one metre, a diameter of 8mm and is filled with 3He at 15 bar. The specification for the WISH detectors included a neutron detection efficiency of 50% at a neutron wavelength of 1Å with good gamma rejection. A position resolution better than 8 mm FWHM along the length of the tubes was also required which has been met experimentally. Results obtained from the detector arrays showing pulse height and positional information both prior to and post installation are shown. The first 5 of the 10 detector panels have been operational since 2009, and comparable diffraction data from powder and single crystal samples taken from the remaining 5 panels (installation completed in 2013) shows that we have a detector array with a highly stable performance which is easily assembled and maintained. Finally some real user data is shown, highlighting the excellent quality of data attainable with this instrument.

Modulation transfer function of partial gating detector by liquid crystal auto-controlling light intensity

NASA Astrophysics Data System (ADS)

Yang, Xusan; Tang, Yuanhe; Liu, Kai; Liu, Hanchen; Gao, Haiyang; Li, Qing; Zhang, Ruixia; Ye, Na; Liang, Yuan; Zhao, Gaoxiang

2008-12-01

Based on the electro-optical properties of liquid crystal, we have designed a novel partial gating detector. Liquid crystal can be taken to change its own transmission according to the light intensity outside. Every single pixel of the image is real-time modulated by liquid crystal, thus the strong light is weakened and low light goes through the detector normally .The purpose of partial-gating strong light (>105lx) can be achieved by this detector. The modulation transfer function (MTF) equations of the main optical sub-systems are calculated in this paper, they are liquid crystal panels, linear fiber panel and CCD array detector. According to the relevant size, the MTF value of this system is fitted out. The result is MTF= 0.518 at Nyquist frequency.

Syndromic Panel-Based Testing in Clinical Microbiology.

PubMed

Ramanan, Poornima; Bryson, Alexandra L; Binnicker, Matthew J; Pritt, Bobbi S; Patel, Robin

2018-01-01

The recent development of commercial panel-based molecular diagnostics for the rapid detection of pathogens in positive blood culture bottles, respiratory specimens, stool, and cerebrospinal fluid has resulted in a paradigm shift in clinical microbiology and clinical practice. This review focuses on U.S. Food and Drug Administration (FDA)-approved/cleared multiplex molecular panels with more than five targets designed to assist in the diagnosis of bloodstream, respiratory tract, gastrointestinal, or central nervous system infections. While these panel-based assays have the clear advantages of a rapid turnaround time and the detection of a large number of microorganisms and promise to improve health care, they present certain challenges, including cost and the definition of ideal test utilization strategies (i.e., optimal ordering) and test interpretation. Copyright © 2017 American Society for Microbiology.

Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

NASA Astrophysics Data System (ADS)

Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

2012-04-01

In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

Use and imaging performance of CMOS flat panel imager with LiF/ZnS(Ag) and Gadox scintillation screens for neutron radiography

NASA Astrophysics Data System (ADS)

Cha, B. K.; kim, J. Y.; Kim, T. J.; Sim, C.; Cho, G.; Lee, D. H.; Seo, C.-W.; Jeon, S.; Huh, Y.

2011-01-01

In digital neutron radiography system, a thermal neutron imaging detector based on neutron-sensitive scintillating screens with CMOS(complementary metal oxide semiconductor) flat panel imager is introduced for non-destructive testing (NDT) application. Recently, large area CMOS APS (active-pixel sensor) in conjunction with scintillation films has been widely used in many digital X-ray imaging applications. Instead of typical imaging detectors such as image plates, cooled-CCD cameras and amorphous silicon flat panel detectors in combination with scintillation screens, we tried to apply a scintillator-based CMOS APS to neutron imaging detection systems for high resolution neutron radiography. In this work, two major Gd2O2S:Tb and 6LiF/ZnS:Ag scintillation screens with various thickness were fabricated by a screen printing method. These neutron converter screens consist of a dispersion of Gd2O2S:Tb and 6LiF/ZnS:Ag scintillating particles in acrylic binder. These scintillating screens coupled-CMOS flat panel imager with 25x50mm2 active area and 48μm pixel pitch was used for neutron radiography. Thermal neutron flux with 6x106n/cm2/s was utilized at the NRF facility of HANARO in KAERI. The neutron imaging characterization of the used detector was investigated in terms of relative light output, linearity and spatial resolution in detail. The experimental results of scintillating screen-based CMOS flat panel detectors demonstrate possibility of high sensitive and high spatial resolution imaging in neutron radiography system.

Luminance uniformity compensation for OLED panels based on FPGA

NASA Astrophysics Data System (ADS)

Ou, Peng; Yang, Gang; Jiang, Quan; Yu, Jun-Sheng; Wu, Qi-Peng; Shang, Fu-Hai; Yin, Wei; Wang, Jun; Zhong, Jian; Luo, Kai-Jun

2009-09-01

Aiming at the problem of luminance uniformity for organic lighting-emitting diode (OLED) panels, a new brightness calculating method based on bilinear interpolation is proposed. The irradiance time of each pixel reaching the same luminance is figured out by Matlab. Adopting the 64×32-pixel, single color and passive matrix OLED panel as adjusting luminance uniformity panel, a new circuit compensating scheme based on FPGA is designed. VHDL is used to make each pixel’s irradiance time in one frame period written in program. The irradiance brightness is controlled by changing its irradiance time, and finally, luminance compensation of the panel is realized. The simulation result indicates that the design is reasonable.

Flat-panel-detector chest radiography: effect of tube voltage on image quality.

PubMed

Uffmann, Martin; Neitzel, Ulrich; Prokop, Mathias; Kabalan, Nahla; Weber, Michael; Herold, Christian J; Schaefer-Prokop, Cornelia

2005-05-01

To compare the visibility of anatomic structures in direct-detector chest radiographs acquired with different tube voltages at equal effective doses to the patient. The study protocol was approved by the institutional internal review board, and written informed consent was obtained from all patients. Posteroanterior chest radiographs of 48 consecutively selected patients were obtained at 90, 121, and 150 kVp by using a flat-panel-detector unit that was based on cesium iodide technology and automated exposure control. Monte Carlo simulations were used to verify that the effective dose for all kilovoltage settings was equal. Five radiologists subjectively and independently rated the delineation of anatomic structures on hard-copy images by using a five-point scale. They also ranked image quality in a blinded side-by-side comparison. Average ranking scores were compared by using one-way analysis of variance with repeated measures. Data were analyzed for the entire patient group and for two patient subgroups that were formed according to body mass index (BMI). The visibility scores of most anatomic structures were significantly superior with the 90-kVp images (mean score, 3.11), followed by the 121-kVp (mean score, 2.95) and 150-kVp images (mean score, 2.80). Differences did not reach significance (P > .05) only for the delineation of the peripheral vessels, the heart contours, and the carina. This was also true for the subgroup of patients (n = 24) with a BMI greater than and the subgroup of patients (n = 24) with a BMI less than the mean BMI (26.9 kg/m(2)). At side-by-side comparison, the readers rated 90-kVp images as having superior image quality in the majority of image triplets; the percentage of 90-kVp images rated as "first choice" ranged from 60% (29 of 48 patients) to 90% (43 of 48 patients), with a median of 88% (42 of 48 patients), among the readers. Delineation of most anatomic structures and overall image quality were ranked superior in digital

[Comparison of noise characteristics of direct and indirect conversion flat panel detectors].

PubMed

Murai, Masami; Kishimoto, Kenji; Tanaka, Katsuhisa; Oota, Kenji; Ienaga, Akinori

2010-11-20

Flat-panel detector (FPD) digital radiography systems have direct and indirect conversion systems, and the 2 conversion systems provide different imaging performances. We measured some imaging performances [input-output characteristic, presampled modulation transfer function (presampled MTF), noise power spectrum (NPS)] of direct and indirect FPD systems. Moreover, some image samples of the NPSs were visually evaluated by the pair comparison method. As a result, the presampled MTF of the direct FPD system was substantially higher than that of the indirect FPD system. The NPS of the direct FPD system had a high value for all spatial frequencies. In contrast, the NPS of the indirect FPD system had a lower value as the frequency became higher. The results of visual evaluations showed the same tendency as that found for NPSs. We elucidated the cause of the difference in NPSs in a simulation study, and we determined that the cause of the difference in the noise components of the direct and indirect FPD systems was closely related to the presampled MTF.

Percutaneous foot joint needle placement using a C-arm flat-panel detector CT.

PubMed

Wiewiorski, Martin; Takes, Martin Thanh Long; Valderrabano, Victor; Jacob, Augustinus Ludwig

2012-03-01

Image guidance is valuable for diagnostic injections in foot orthopaedics. Flat-detector computed tomography (FD-CT) was implemented using a C-arm, and the system was tested for needle guidance in foot joint injections. FD-CT-guided joint infiltration was performed in 6 patients referred from the orthopaedic department for diagnostic foot injections. All interventions were performed utilising a flat-panel fluoroscopy system utilising specialised image guidance and planning software. Successful infiltration was defined by localisation of contrast media depot in the targeted joint. The pre- and post-interventional numeric analogue scale (NAS) pain score was assessed. All injections were technically successful. Contrast media deposit was documented in all targeted joints. Significant relief of symptoms was noted by all 6 participants. FD-CT-guided joint infiltration is a feasible method for diagnostic infiltration of midfoot and hindfoot joints. The FD-CT approach may become an alternative to commonly used 2D-fluoroscopically guidance.

Flat Panel Space Based Space Surveillance Sensor

NASA Astrophysics Data System (ADS)

Kendrick, R.; Duncan, A.; Wilm, J.; Thurman, S. T.; Stubbs, D. M.; Ogden, C.

2013-09-01

Traditional electro-optical (EO) imaging payloads consist of an optical telescope to collect the light from the object scene and map the photons to an image plane to be digitized by a focal plane detector array. The size, weight, and power (SWaP) for the traditional EO imager is dominated by the optical telescope, driven primarily by the large optics, large stiff structures, and the thermal control needed to maintain precision free-space optical alignments. We propose a non-traditional Segmented Planar Imaging Detector for EO Reconnaissance (SPIDER) imager concept that is designed to substantially reduce SWaP, by at least an order of magnitude. SPIDER maximizes performance by providing a larger effective diameter (resolution) while minimizing mass and cost. SPIDER replaces the traditional optical telescope and digital focal plane detector array with a densely packed interferometer array based on emerging photonic integrated circuit (PIC) technologies. Lenslets couple light from the object into a set of waveguides on a PIC. Light from each lenslet is distributed among different waveguides by both field angle and optical frequency, and the lenslets are paired up to form unique interferometer baselines by combining light from different waveguides. The complex spatial coherence of the object (for each field angle, frequency, and baseline) is measured with a balanced four quadrature detection scheme. By the Van-Cittert Zernike Theorem, each measurement corresponds to a unique Fourier component of the incoherent object intensity distribution. Finally, an image reconstruction algorithm is used to invert all the data and form an image. Our approach replaces the large optics and structures required by a conventional telescope with PICs that are accommodated by standard lithographic fabrication techniques (e.g., CMOS fabrication). The standard EO payload integration and test process which involves precision alignment and test of optical components to form a diffraction

61. Upper panel in cornerpower panel lcpa lower panel in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

61. Upper panel in corner-power panel lcpa lower panel in corner-oxygen regeneration unit, at right-air conditioner control panel, on floor-bio-pack 45 for emergency breathing, looking northwest - Ellsworth Air Force Base, Delta Flight, Launch Control Facility, County Road CS23A, North of Exit 127, Interior, Jackson County, SD

Imaging responses of on-site CsI and Gd2O2S flat-panel detectors: Dependence on the tube voltage

NASA Astrophysics Data System (ADS)

Jeon, Hosang; Chung, Myung Jin; Youn, Seungman; Nam, Jiho; Lee, Jayoung; Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Ho Kyung

2015-07-01

One of the emerging issues in radiography is low-dose imaging to minimize patient's exposure. The scintillating materials employed in most indirect flat-panel detectors show a drastic change of X-ray photon absorption efficiency around their K-edge energies that consequently affects image quality. Using various tube voltages, we investigated the imaging performance of most popular scintillators: cesium iodide (CsI) and gadolinium oxysulfide (Gd2O2S). The integrated detective quantum efficiencies (iDQE) of four detectors installed in the same hospital were evaluated according to the standardized procedure IEC 62220-1 at tube voltages of 40 - 120 kVp. The iDQE values of the Gd2O2S detectors were normalized by those of CsI detectors to exclude the effects of image postprocessing. The contrast-to-noise ratios (CNR) were also evaluated by using an anthropomorphic chest phantom. The iDQE of the CsI detector outperformed that of the Gd2O2S detector over all tube voltages. Moreover, we noted that the iDQE of the Gd2O2S detectors quickly rolled off with decreasing tube voltage under 70 kVp. The CNRs of the two scintillators were similar at 120 kVp. At 60 kVp, however, the CNR of Gd2O2S was about half that of CsI. Compared to the Gd2O2S detectors, variations in the DQE performance of the CsI detectors were relatively immune to variations in the applied tube voltages. Therefore, we claim that Gd2O2S detectors are inappropriate for use in low-tube-voltage imaging (e.g., extremities and pediatrics) with low patient exposure.

A nonlinear lag correction algorithm for a-Si flat-panel x-ray detectors

PubMed Central

Starman, Jared; Star-Lack, Josh; Virshup, Gary; Shapiro, Edward; Fahrig, Rebecca

2012-01-01

Purpose: Detector lag, or residual signal, in a-Si flat-panel (FP) detectors can cause significant shading artifacts in cone-beam computed tomography reconstructions. To date, most correction models have assumed a linear, time-invariant (LTI) model and correct lag by deconvolution with an impulse response function (IRF). However, the lag correction is sensitive to both the exposure intensity and the technique used for determining the IRF. Even when the LTI correction that produces the minimum error is found, residual artifact remains. A new non-LTI method was developed to take into account the IRF measurement technique and exposure dependencies. Methods: First, a multiexponential (N = 4) LTI model was implemented for lag correction. Next, a non-LTI lag correction, known as the nonlinear consistent stored charge (NLCSC) method, was developed based on the LTI multiexponential method. It differs from other nonlinear lag correction algorithms in that it maintains a consistent estimate of the amount of charge stored in the FP and it does not require intimate knowledge of the semiconductor parameters specific to the FP. For the NLCSC method, all coefficients of the IRF are functions of exposure intensity. Another nonlinear lag correction method that only used an intensity weighting of the IRF was also compared. The correction algorithms were applied to step-response projection data and CT acquisitions of a large pelvic phantom and an acrylic head phantom. The authors collected rising and falling edge step-response data on a Varian 4030CB a-Si FP detector operating in dynamic gain mode at 15 fps at nine incident exposures (2.0%–92% of the detector saturation exposure). For projection data, 1st and 50th frame lag were measured before and after correction. For the CT reconstructions, five pairs of ROIs were defined and the maximum and mean signal differences within a pair were calculated for the different exposures and step-response edge techniques. Results: The LTI

Pillar-structured neutron detector based multiplicity system

NASA Astrophysics Data System (ADS)

Murphy, John W.; Shao, Qinghui; Voss, Lars F.; Kerr, Phil L.; Fabris, Lorenzo; Conway, Adam M.; Nikolic, Rebecca J.

2018-01-01

This work demonstrates the potential of silicon pillars filled with boron-10 as a sensor technology for a compact and portable neutron multiplicity system. Solid-state, semiconductor based neutron detectors may enable completely new detector form factors, offer an alternate approach to helium-3 based systems, and reduce detector weight and volume requirements. Thirty-two pillar-structured neutron detectors were assembled into a system with an active area of over 20 cm2 and were used in this work to demonstrate the feasibility of this sensor technology as a potential replacement for helium-3 based gas detectors. Multiplicity measurements were successfully carried out using a californium-252 neutron source, in which the source mass, system efficiency, and die-away time were determined. This demonstration shows that these solid-state detectors could allow for a more compact and portable system that could be used for special nuclear material identification in the field.

Musculoskeletal imaging with a prototype photon-counting detector.

PubMed

Gruber, M; Homolka, P; Chmeissani, M; Uffmann, M; Pretterklieber, M; Kainberger, F

2012-01-01

To test a digital imaging X-ray device based on the direct capture of X-ray photons with pixel detectors, which are coupled with photon-counting readout electronics. The chip consists of a matrix of 256 × 256 pixels with a pixel pitch of 55 μm. A monolithic image of 11.2 cm × 7 cm was obtained by the consecutive displacement approach. Images of embalmed anatomical specimens of eight human hands were obtained at four different dose levels (skin dose 2.4, 6, 12, 25 μGy) with the new detector, as well as with a flat-panel detector. The overall rating scores for the evaluated anatomical regions ranged from 5.23 at the lowest dose level, 6.32 at approximately 6 μGy, 6.70 at 12 μGy, to 6.99 at the highest dose level with the photon-counting system. The corresponding rating scores for the flat-panel detector were 3.84, 5.39, 6.64, and 7.34. When images obtained at the same dose were compared, the new system outperformed the conventional DR system at the two lowest dose levels. At the higher dose levels, there were no significant differences between the two systems. The photon-counting detector has great potential to obtain musculoskeletal images of excellent quality at very low dose levels.

Active Well Counting Using New PSD Plastic Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hausladen, Paul; Newby, Jason; McElroy, Robert Dennis

This report presents results and analysis from a series of proof-of-concept measurements to assess the suitability of segmented detectors constructed from Eljen EJ-299-34 PSD-plastic scintillator with pulse-shape discrimination capability for the purposes of quantifying uranium via active neutron coincidence counting. Present quantification of bulk uranium materials for international safeguards and domestic materials control and accounting relies on active neutron coincidence counting systems, such as the Active Well Coincidence Counter (AWCC) and the Uranium Neutron Coincidence Collar (UNCL), that use moderated He-3 proportional counters along with necessarily low-intensity 241Am(Li) neutron sources. Scintillation-based fast-neutron detectors are a potentially superior technology to themore » existing AWCC and UNCL designs due to their spectroscopic capability and their inherently short neutron coincidence times that largely eliminate random coincidences and enable interrogation by stronger sources. One of the past impediments to the investigation and adoption of scintillation counters for the purpose of quantifying bulk uranium was the commercial availability of scintillators having the necessary neutron-gamma pulse-shape discrimination properties only as flammable liquids. Recently, Eljen EJ-299-34 PSD-plastic scintillator became commercially available. The present work is the first assessment of an array of PSD-plastic detectors for the purposes of quantifying bulk uranium. The detector panel used in the present work was originally built as the focal plane for a fast-neutron imager, but it was repurposed for the present investigation by construction of a stand to support the inner well of an AWCC immediately in front of the detector panel. The detector panel and data acquisition of this system are particularly well suited for performing active-well fast-neutron counting of LEU and HEU samples because the active detector volume is solid, the 241Am

Noise, sampling, and the number of projections in cone-beam CT with a flat-panel detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Z.; Gang, G. J.; Siewerdsen, J. H., E-mail: jeff.siewerdsen@jhu.edu

2014-06-15

Purpose: To investigate the effect of the number of projection views on image noise in cone-beam CT (CBCT) with a flat-panel detector. Methods: This fairly fundamental consideration in CBCT system design and operation was addressed experimentally (using a phantom presenting a uniform medium as well as statistically motivated “clutter”) and theoretically (using a cascaded systems model describing CBCT noise) to elucidate the contributing factors of quantum noise (σ{sub Q}), electronic noise (σ{sub E}), and view aliasing (σ{sub view}). Analysis included investigation of the noise, noise-power spectrum, and modulation transfer function as a function of the number of projections (N{sub proj}),more » dose (D{sub tot}), and voxel size (b{sub vox}). Results: The results reveal a nonmonotonic relationship between image noise andN{sub proj} at fixed total dose: for the CBCT system considered, noise decreased with increasing N{sub proj} due to reduction of view sampling effects in the regime N{sub proj} <∼200, above which noise increased with N{sub proj} due to increased electronic noise. View sampling effects were shown to depend on the heterogeneity of the object in a direct analytical relationship to power-law anatomical clutter of the form κ/f {sup β}—and a general model of individual noise components (σ{sub Q}, σ{sub E}, and σ{sub view}) demonstrated agreement with measurements over a broad range in N{sub proj}, D{sub tot}, and b{sub vox}. Conclusions: The work elucidates fairly basic elements of CBCT noise in a manner that demonstrates the role of distinct noise components (viz., quantum, electronic, and view sampling noise). For configurations fairly typical of CBCT with a flat-panel detector (FPD), the analysis reveals a “sweet spot” (i.e., minimum noise) in the rangeN{sub proj} ∼ 250–350, nearly an order of magnitude lower in N{sub proj} than typical of multidetector CT, owing to the relatively high electronic noise in FPDs. The analysis

Pillar-structured neutron detector based multiplicity system

DOE PAGES

Murphy, John W.; Shao, Qinghui; Voss, Lars F.; ...

2017-10-04

This work demonstrates the potential of silicon pillars filled with boron-10 as a sensor technology for a compact and portable neutron multiplicity system. Solid-state, semiconductor based neutron detectors may enable completely new detector form factors, offer an alternate approach to helium-3 based systems, and reduce detector weight and volume requirements. Thirty-two pillar-structured neutron detectors were assembled into a system with an active area of over 20 cm 2 and were used in this work to demonstrate the feasibility of this sensor technology as a potential replacement for helium-3 based gas detectors. Multiplicity measurements were successfully carried out using a californium-252more » neutron source, in which the source mass, system efficiency, and die-away time were determined. As a result, this demonstration shows that these solid-state detectors could allow for a more compact and portable system that could be used for special nuclear material identification in the field.« less

Performance Study of an aSi Flat Panel Detector for Fast Neutron Imaging of Nuclear Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumann, M.; Mauerhofer, E.; Engels, R.

Radioactive waste must be characterized to check its conformance for intermediate storage and final disposal according to national regulations. For the determination of radio-toxic and chemo-toxic contents of radioactive waste packages non-destructive analytical techniques are preferentially used. Fast neutron imaging is a promising technique to assay large and dense items providing, in complementarity to photon imaging, additional information on the presence of structures in radioactive waste packages. Therefore the feasibility of a compact Neutron Imaging System for Radioactive waste Analysis (NISRA) using 14 MeV neutrons is studied in a cooperation framework of Forschungszentrum Juelich GmbH, RWTH Aachen University and Siemensmore » AG. However due to the low neutron emission of neutron generators in comparison to research reactors the challenging task resides in the development of an imaging detector with a high efficiency, a low sensitivity to gamma radiation and a resolution sufficient for the purpose. The setup is composed of a commercial D-T neutron generator (Genie16GT, Sodern) with a surrounding shielding made of polyethylene, which acts as a collimator and an amorphous silicon flat panel detector (aSi, 40 x 40 cm{sup 2}, XRD-1642, Perkin Elmer). Neutron detection is achieved using a general propose plastic scintillator (EJ-260, Eljen Technology) linked to the detector. The thermal noise of the photodiodes is reduced by employing an entrance window made of aluminium. Optimal gain and integration time for data acquisition are set by measuring the response of the detector to the radiation of a 500 MBq {sup 241}Am-source. Detector performance was studied by recording neutron radiography images of materials with various, but well known, chemical compositions, densities and dimensions (Al, C, Fe, Pb, W, concrete, polyethylene, 5 x 8 x 10 cm{sup 3}). To simulate gamma-ray emitting waste radiographs in presence of a gamma-ray sources ({sup 60}Co, {sup 137}Cs

Image reconstruction in cone-beam CT with a spherical detector using the BPF algorithm

NASA Astrophysics Data System (ADS)

Zuo, Nianming; Zou, Yu; Jiang, Tianzi; Pan, Xiaochuan

2006-03-01

Both flat-panel detectors and cylindrical detectors have been used in CT systems for data acquisition. The cylindrical detector generally offers a sampling of a transverse image plane more uniformly than does a flat-panel detector. However, in the longitudinal dimension, the cylindrical and flat-panel detectors offer similar sampling of the image space. In this work, we investigate a detector of spherical shape, which can yield uniform sampling of the 3D image space because the solid angle subtended by each individual detector bin remains unchanged. We have extended the backprojection-filtration (BPF) algorithm, which we have developed previously for cone-beam CT, to reconstruct images in cone-beam CT with a spherical detector. We also conduct computer-simulation studies to validate the extended BPF algorithm. Quantitative results in these numerical studies indicate that accurate images can be obtained from data acquired with a spherical detector by use of our extended BPF cone-beam algorithms.

Indirect flat-panel detector with avalanche gain: Fundamental feasibility investigation for SHARP-AMFPI (scintillator HARP active matrix flat panel imager)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao Wei; Li Dan; Reznik, Alla

2005-09-15

An indirect flat-panel imager (FPI) with avalanche gain is being investigated for low-dose x-ray imaging. It is made by optically coupling a structured x-ray scintillator CsI(Tl) to an amorphous selenium (a-Se) avalanche photoconductor called HARP (high-gain avalanche rushing photoconductor). The final electronic image is read out using an active matrix array of thin film transistors (TFT). We call the proposed detector SHARP-AMFPI (scintillator HARP active matrix flat panel imager). The advantage of the SHARP-AMFPI is its programmable gain, which can be turned on during low dose fluoroscopy to overcome electronic noise, and turned off during high dose radiography to avoidmore » pixel saturation. The purpose of this paper is to investigate the important design considerations for SHARP-AMFPI such as avalanche gain, which depends on both the thickness d{sub Se} and the applied electric field E{sub Se} of the HARP layer. To determine the optimal design parameter and operational conditions for HARP, we measured the E{sub Se} dependence of both avalanche gain and optical quantum efficiency of an 8 {mu}m HARP layer. The results were used in a physical model of HARP as well as a linear cascaded model of the FPI to determine the following x-ray imaging properties in both the avalanche and nonavalanche modes as a function of E{sub Se}: (1) total gain (which is the product of avalanche gain and optical quantum efficiency); (2) linearity; (3) dynamic range; (4) gain nonuniformity resulting from thickness nonuniformity; and (5) effects of direct x-ray interaction in HARP. Our results showed that a HARP layer thickness of 8 {mu}m can provide adequate avalanche gain and sufficient dynamic range for x-ray imaging applications to permit quantum limited operation over the range of exposures needed for radiography and fluoroscopy.« less

Uterine Artery Embolization for Leiomyomata: Optimization of the Radiation Dose to the Patient Using a Flat-Panel Detector Angiographic Suite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sapoval, Marc, E-mail: marc.sapoval2@egp.aphp.fr; Pellerin, Olivier; Rehel, Jean-Luc

The purpose of this study was to assess the ability of low-dose/low-frame fluoroscopy/angiography with a flat-panel detector angiographic suite to reduce the dose delivered to patients during uterine fibroid embolization (UFE). A two-step prospective dosimetric study was conducted, with a flat-panel detector angiography suite (Siemens Axiom Artis) integrating automatic exposure control (AEC), during 20 consecutive UFEs. Patient dosimetry was performed using calibrated thermoluminescent dosimeters placed on the lower posterior pelvis skin. The first step (10 patients; group A) consisted in UFE (bilateral embolization, calibrated microspheres) performed using the following parameters: standard fluoroscopy (15 pulses/s) and angiography (3 frames/s). The secondmore » step (next consecutive 10 patients; group B) used low-dose/low-frame fluoroscopy (7.5 pulses/s for catheterization and 3 pulses/s for embolization) and angiography (1 frame/s). We also recorded the total dose-area product (DAP) delivered to the patient and the fluoroscopy time as reported by the manufacturer's dosimetry report. The mean peak skin dose decreased from 2.4 {+-} 1.3 to 0.4 {+-} 0.3 Gy (P = 0.001) for groups A and B, respectively. The DAP values decreased from 43,113 {+-} 27,207 {mu}Gy m{sup 2} for group A to 9,515 {+-} 4,520 {mu}Gy m{sup 2} for group B (P = 0.003). The dose to ovaries and uterus decreased from 378 {+-} 238 mGy (group A) to 83 {+-} 41 mGy (group B) and from 388 {+-} 246 mGy (group A) to 85 {+-} 39 mGy (group B), respectively. Effective doses decreased from 112 {+-} 71 mSv (group A) to 24 {+-} 12 mSv (group B) (P = 0.003). In conclusion, the use of low-dose/low-frame fluoroscopy/angiography, based on a good understanding of the AEC system and also on the technique during uterine fibroid embolization, allows a significant decrease in the dose exposure to the patient.« less

Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment

PubMed Central

Pjontek, Rastislav; Önenköprülü, Belgin; Scholz, Bernhard; Kyriakou, Yiannis; Schubert, Gerrit A; Othman, Ahmed; Wiesmann, Martin; Brockmann, Marc A

2016-01-01

Background Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. Objective To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. Methods Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. Results MAR improved the assessability of the brain parenchyma and small vessels (diameter <1 mm) in the neighborhood of metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. Conclusions When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips. PMID:26346458

HVI-Test Setup for Debris Detector Verification

NASA Astrophysics Data System (ADS)

Bauer, Waldemar; Romberg, Oliver; Wiedemann, Carsten; Putzar, Robin; Drolshagen, Gerhard; Vorsmann, Peter

2013-08-01

Risk assessment concerning impacting space debris or micrometeoroids with spacecraft or payloads can be performed by using environmental models such as MASTER (ESA) or ORDEM (NASA). The validation of such models is performed by comparison of simulated results with measured data. Such data can be obtained from ground-based or space-based radars or telescopes, or by analysis of space hardware (e.g. Hubble Space Telescope, Space Shuttle Windows), which are retrieved from orbit. An additional data source is in-situ impact detectors, which are purposed for the collection of space debris and micrometeoroids impact data. In comparison to the impact data gained by analysis of the retrieved surfaces, the detected data contains additional information regarding impact time and orbit. In the past, many such in-situ detectors have been developed, with different measurement methods for the identification and classification of impacting objects. However, existing detectors have a drawback in terms of data acquisition. Generally the detection area is small, limiting the collected data as the number of recorded impacts has a linear dependence to the exposed area. An innovative impact detector concept is currently under development at the German Aerospace Centre (DLR) in Bremen, in order to increase the surface area while preserving the advantages offered by dedicated in-situ impact detectors. The Solar Generator based Impact Detector (SOLID) is not an add-on component on the spacecraft, making it different to all previous impact detectors. SOLID utilises existing subsystems of the spacecraft and adapts them for impact detection purposes. Solar generators require large panel surfaces in order to provide the spacecraft with sufficient energy. Therefore, the spacecraft solar panels provide a perfect opportunity for application as impact detectors. Employment of the SOLID method in several spacecraft in various orbits would serve to significantly increase the spatial coverage

DQE simulation of a-Se x-ray detectors using ARTEMIS

NASA Astrophysics Data System (ADS)

Fang, Yuan; Badano, Aldo

2016-03-01

Detective Quantum Efficiency (DQE) is one of the most important image quality metrics for evaluating the spatial resolution performance of flat-panel x-ray detectors. In this work, we simulate the DQE of amorphous selenium (a-Se) xray detectors with a detailed Monte Carlo transport code (ARTEMIS) for modeling semiconductor-based direct x-ray detectors. The transport of electron-hole pairs is achieved with a spatiotemporal model that accounts for recombination and trapping of carriers and Coulombic effects of space charge and external applied electric field. A range of x-ray energies has been simulated from 10 to 100 keV. The DQE results can be used to study the spatial resolution characteristics of detectors at different energies.

Aerosol-based detectors for liquid chromatography.

PubMed

Magnusson, Lars-Erik; Risley, Donald S; Koropchak, John A

2015-11-20

Aerosol-based detectors developed within the last few decades have increasingly addressed the need for sensitive, universal liquid chromatography detection in a wide variety of applications. Herein, we review the operating principles, instrumentation, analytical characteristics, and recent applications of the three general types of such detectors: evaporative light scattering detection (ELSD), condensation nucleation light scattering detection (CNLSD); commercially known as the nano-quantity analyte detector (NQAD), and charged aerosol detection (CAD). Included is a comparative evaluation of the operational and analytical characteristics of these detectors. Copyright © 2015 Elsevier B.V. All rights reserved.

Towards a high sensitivity small animal PET system based on CZT detectors (Conference Presentation)

NASA Astrophysics Data System (ADS)

Abbaszadeh, Shiva; Levin, Craig

2017-03-01

Small animal positron emission tomography (PET) is a biological imaging technology that allows non-invasive interrogation of internal molecular and cellular processes and mechanisms of disease. New PET molecular probes with high specificity are under development to target, detect, visualize, and quantify subtle molecular and cellular processes associated with cancer, heart disease, and neurological disorders. However, the limited uptake of these targeted probes leads to significant reduction in signal. There is a need to advance the performance of small animal PET system technology to reach its full potential for molecular imaging. Our goal is to assemble a small animal PET system based on CZT detectors and to explore methods to enhance its photon sensitivity. In this work, we reconstruct an image from a phantom using a two-panel subsystem consisting of six CZT crystals in each panel. For image reconstruction, coincidence events with energy between 450 and 570 keV were included. We are developing an algorithm to improve sensitivity of the system by including multiple interaction events.

High Strength Wood-based Sandwich Panels reinforced with fiberglass and foam

Treesearch

Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

2014-01-01

Mechanical analysis is presented for new high-strengthsandwich panels made from wood-based phenolic impregnated laminated paper assembled with an interlocking tri-axial ribbed core. Four different panel configurations were tested, including panels with fiberglass fabric bonded to both outside faces with self-expanding urethane foam used to fill the ribbed core. The...

Image quality and radiation dose on digital chest imaging: comparison of amorphous silicon and amorphous selenium flat-panel systems.

PubMed

Bacher, Klaus; Smeets, Peter; Vereecken, Ludo; De Hauwere, An; Duyck, Philippe; De Man, Robert; Verstraete, Koenraad; Thierens, Hubert

2006-09-01

The aim of this study was to compare the image quality and radiation dose in chest imaging using an amorphous silicon flat-panel detector system and an amorphous selenium flat-panel detector system. In addition, the low-contrast performance of both systems with standard and low radiation doses was compared. In two groups of 100 patients each, digital chest radiographs were acquired with either an amorphous silicon or an amorphous selenium flat-panel system. The effective dose of the examination was measured using thermoluminescent dosimeters placed in an anthropomorphic Rando phantom. The image quality of the digital chest radiographs was assessed by five experienced radiologists using the European Guidelines on Quality Criteria for Diagnostic Radiographic Images. In addition, a contrast-detail phantom study was set up to assess the low-contrast performance of both systems at different radiation dose levels. Differences between the two groups were tested for significance using the two-tailed Mann-Whitney test. The amorphous silicon flat-panel system allowed an important and significant reduction in effective dose in comparison with the amorphous selenium flat-panel system (p < 0.0001) for both the posteroanterior and lateral views. In addition, clinical image quality analysis showed that the dose reduction was not detrimental to image quality. Compared with the amorphous selenium flat-panel detector system, the amorphous silicon flat-panel detector system performed significantly better in the low-contrast phantom study, with phantom entrance dose values of up to 135 muGy. Chest radiographs can be acquired with a significantly lower patient radiation dose using an amorphous silicon flat-panel system than using an amorphous selenium flat-panel system, thereby producing images that are equal or even superior in quality to those of the amorphous selenium flat-panel detector system.

Performance Evaluation of Large Aperture 'Polished Panel' Optical Receivers Based on Experimental Data

NASA Technical Reports Server (NTRS)

Vilnrotter, Victor

2013-01-01

Recent interest in hybrid RF/Optical communications has led to the development and installation of a "polished-panel" optical receiver evaluation assembly on the 34-meter research antenna at Deep-Space Station 13 (DSS-13) at NASA's Goldstone Communications Complex. The test setup consists of a custom aluminum panel polished to optical smoothness, and a large-sensor CCD camera designed to image the point-spread function (PSF) generated by the polished aluminum panel. Extensive data has been obtained via realtime tracking and imaging of planets and stars at DSS-13. Both "on-source" and "off-source" data were recorded at various elevations, enabling the development of realistic simulations and analytic models to help determine the performance of future deep-space communications systems operating with on-off keying (OOK) or pulse-position-modulated (PPM) signaling formats with photon-counting detection, and compared with the ultimate quantum bound on detection performance for these modulations. Experimentally determined PSFs were scaled to provide realistic signal-distributions across a photon-counting detector array when a pulse is received, and uncoded as well as block-coded performance analyzed and evaluated for a well-known class of block codes.

New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy

PubMed Central

Rudin, Stephen; Kuhls, Andrew T.; Yadava, Girijesh K.; Josan, Gaurav C.; Wu, Ye; Chityala, Ravishankar N.; Rangwala, Hussain S.; Ciprian Ionita, N.; Hoffmann, Kenneth R.; Bednarek, Daniel R.

2011-01-01

New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 × 20 cm can be obtained where the images have pixel-resolution of 100 µm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 µR detector exposure per frame. Because of the flexible voltage controlled gain of the LA’s and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels. PMID:21297904

New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy

NASA Astrophysics Data System (ADS)

Rudin, Stephen; Kuhls, Andrew T.; Yadava, Girijesh K.; Josan, Gaurav C.; Wu, Ye; Chityala, Ravishankar N.; Rangwala, Hussain S.; Ionita, N. Ciprian; Hoffmann, Kenneth R.; Bednarek, Daniel R.

2006-03-01

New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 x 20 cm can be obtained where the images have pixel-resolution of 100 μm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 μR detector exposure per frame. Because of the flexible voltage controlled gain of the LA's and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels.

Analysis of laser jamming to satellite-based detector

NASA Astrophysics Data System (ADS)

Wang, Si-wen; Guo, Li-hong; Guo, Ru-hai

2009-07-01

The reconnaissance satellite, communication satellite and navigation satellite used in the military applications have played more and more important role in the advanced technique wars and already become the significant support and aid system for military actions. With the development of all kinds of satellites, anti-satellite laser weapons emerge as the times require. The experiments and analyses of laser disturbing CCD (charge coupled detector) in near ground have been studied by many research groups, but their results are not suitable to the case that using laser disturbs the satellite-based detector. Because the distance between the satellite-based detector and the ground is very large, it is difficult to damage it directly. However the optical receive system of satellite detector has large optical gain, so laser disturbing satellite detector is possible. In order to determine its feasibility, the theoretical analyses and experimental study are carried out in the paper. Firstly, the influence factors of laser disturbing satellite detector are analyzed in detail, which including laser power density on the surface of the detector after long distance transmission, and laser power density threshold for disturbing etc. These factors are not only induced by the satellite orbit, but dependence on the following parameters: laser average power in the ground, laser beam quality, tracing and aiming precision and atmospheric transmission. A calculation model is developed by considering all factors which then the power density entering into the detector can be calculated. Secondly, the laser disturbing experiment is performed by using LD (laser diode) with the wavelength 808 nm disturbing CCD 5 kilometer away, which the disturbing threshold value is obtained as 3.55×10-4mW/cm2 that coincides with other researcher's results. Finally, using the theoretical model, the energy density of laser on the photosensitive surface of MSTI-3 satellite detector is estimated as about 100m

QCL-based standoff and proximal chemical detectors

NASA Astrophysics Data System (ADS)

Dupuis, Julia R.; Hensley, Joel; Cosofret, Bogdan R.; Konno, Daisei; Mulhall, Phillip; Schmit, Thomas; Chang, Shing; Allen, Mark; Marinelli, William J.

2016-05-01

The development of two longwave infrared quantum cascade laser (QCL) based surface contaminant detection platforms supporting government programs will be discussed. The detection platforms utilize reflectance spectroscopy with application to optically thick and thin materials including solid and liquid phase chemical warfare agents, toxic industrial chemicals and materials, and explosives. Operation at standoff (10s of m) and proximal (1 m) ranges will be reviewed with consideration given to the spectral signatures contained in the specular and diffusely reflected components of the signal. The platforms comprise two variants: Variant 1 employs a spectrally tunable QCL source with a broadband imaging detector, and Variant 2 employs an ensemble of broadband QCLs with a spectrally selective detector. Each variant employs a version of the Adaptive Cosine Estimator for detection and discrimination in high clutter environments. Detection limits of 5 μg/cm2 have been achieved through speckle reduction methods enabling detector noise limited performance. Design considerations for QCL-based standoff and proximal surface contaminant detectors are discussed with specific emphasis on speckle-mitigated and detector noise limited performance sufficient for accurate detection and discrimination regardless of the surface coverage morphology or underlying surface reflectivity. Prototype sensors and developmental test results will be reviewed for a range of application scenarios. Future development and transition plans for the QCL-based surface detector platforms are discussed.

Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment.

PubMed

Pjontek, Rastislav; Önenköprülü, Belgin; Scholz, Bernhard; Kyriakou, Yiannis; Schubert, Gerrit A; Nikoubashman, Omid; Othman, Ahmed; Wiesmann, Martin; Brockmann, Marc A

2016-08-01

Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. MAR improved the assessability of the brain parenchyma and small vessels (diameter <1 mm) in the neighborhood of metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

A DBN based anomaly targets detector for HSI

NASA Astrophysics Data System (ADS)

Ma, Ning; Wang, Shaojun; Yu, Jinxiang; Peng, Yu

2017-10-01

Due to the assumption that Hyperspectral image (HSI) should conform to Gaussian distribution, traditional Mahalanobis distance-based anomaly targets detectors perform poor because the assumption may not always hold. In order to solve those problems, a deep learning based detector, Deep Belief Network(DBN) anomaly detector(DBN-AD), was proposed to fit the unknown distribution of HSI by energy modeling, the reconstruction errors of this encode-decode processing are used for discriminating the anomaly targets. Experiments are implemented on real and synthesized HSI dataset which collection by Airborne Visible Infra-Red Imaging Spectrometer (AVIRIS). Comparing to classic anomaly detector, the proposed method shows better performance, it performs about 0.17 higher in Area Under ROC Curve (AUC) than that of Reed-Xiaoli detector(RXD) and Kernel-RXD (K-RXD).

Experiences with radiation portal detectors for international rail transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stromswold, David C.; McCormick, Kathleen R.; Todd, Lindsay C.

Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm × 10-cm × 41-cm) and a PVT panel with a 41 cm × 173 cm × 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars createsmore » a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site the trains carried inter-modal containers that had been unloaded from ships, and at the other site the trains contained bulk cargo or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting program GADRAS/FitToDB from Sandia National Laboratories. For much of the NORM the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases.« less

Workshop on detectors for third-generation synchrotron sources: Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1994-12-01

The aims of the workshop were (1) to acquaint APS users with current R and D being carried out on detectors, (2) to identify new detector systems possible during the next five years, (3) to identify new detectors theoretically possible in the future, (4) to stimulate interactions between user groups and detector developers, and (5) to obtain recommendations from expert panels on technical issues needing resolution. Development of detectors at ESRF, Spring-8, BNL, CERN and LBL are included.

Beyond the Sparsity-Based Target Detector: A Hybrid Sparsity and Statistics Based Detector for Hyperspectral Images.

PubMed

Du, Bo; Zhang, Yuxiang; Zhang, Liangpei; Tao, Dacheng

2016-08-18

Hyperspectral images provide great potential for target detection, however, new challenges are also introduced for hyperspectral target detection, resulting that hyperspectral target detection should be treated as a new problem and modeled differently. Many classical detectors are proposed based on the linear mixing model and the sparsity model. However, the former type of model cannot deal well with spectral variability in limited endmembers, and the latter type of model usually treats the target detection as a simple classification problem and pays less attention to the low target probability. In this case, can we find an efficient way to utilize both the high-dimension features behind hyperspectral images and the limited target information to extract small targets? This paper proposes a novel sparsitybased detector named the hybrid sparsity and statistics detector (HSSD) for target detection in hyperspectral imagery, which can effectively deal with the above two problems. The proposed algorithm designs a hypothesis-specific dictionary based on the prior hypotheses for the test pixel, which can avoid the imbalanced number of training samples for a class-specific dictionary. Then, a purification process is employed for the background training samples in order to construct an effective competition between the two hypotheses. Next, a sparse representation based binary hypothesis model merged with additive Gaussian noise is proposed to represent the image. Finally, a generalized likelihood ratio test is performed to obtain a more robust detection decision than the reconstruction residual based detection methods. Extensive experimental results with three hyperspectral datasets confirm that the proposed HSSD algorithm clearly outperforms the stateof- the-art target detectors.

Improved fatigue performance for wood-based structural panels using slot and tab construction

Treesearch

Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

2016-01-01

This paper presents static and fatigue bending behavior for a wood-based structural panel having a slot and tab (S/T) construction technique. Comparisons were made with similarly fabricated panels without the S/T construction technique. Experimental results showed that both types of panels had similar bending properties in the static tests. However, the panels with S/T...

A Rotatable Quality Control Phantom for Evaluating the Performance of Flat Panel Detectors in Imaging Moving Objects.

PubMed

Haga, Yoshihiro; Chida, Koichi; Inaba, Yohei; Kaga, Yuji; Meguro, Taiichiro; Zuguchi, Masayuki

2016-02-01

As the use of diagnostic X-ray equipment with flat panel detectors (FPDs) has increased, so has the importance of proper management of FPD systems. To ensure quality control (QC) of FPD system, an easy method for evaluating FPD imaging performance for both stationary and moving objects is required. Until now, simple rotatable QC phantoms have not been available for the easy evaluation of the performance (spatial resolution and dynamic range) of FPD in imaging moving objects. We developed a QC phantom for this purpose. It consists of three thicknesses of copper and a rotatable test pattern of piano wires of various diameters. Initial tests confirmed its stable performance. Our moving phantom is very useful for QC of FPD images of moving objects because it enables visual evaluation of image performance (spatial resolution and dynamic range) easily.

Evaluation of detector dynamic range in the x-ray exposure domain in mammography: a comparison between film-screen and flat panel detector systems.

PubMed

Cooper, Virgil N; Oshiro, Thomas; Cagnon, Christopher H; Bassett, Lawrence W; McLeod-Stockmann, Tyler M; Bezrukiy, Nikita V

2003-10-01

Digital detectors in mammography have wide dynamic range in addition to the benefit of decoupled acquisition and display. How wide the dynamic range is and how it compares to film-screen systems in the clinical x-ray exposure domain are unclear. In this work, we compare the effective dynamic ranges of film-screen and flat panel mammography systems, along with the dynamic ranges of their component image receptors in the clinical x-ray exposure domain. An ACR mammography phantom was imaged using variable mAs (exposure) values for both systems. The dynamic range of the contrast-limited film-screen system was defined as that ratio of mAs (exposure) values for a 26 kVp Mo/Mo (HVL=0.34 mm Al) beam that yielded passing phantom scores. The same approach was done for the noise-limited digital system. Data from three independent observers delineated a useful phantom background optical density range of 1.27 to 2.63, which corresponded to a dynamic range of 2.3 +/- 0.53. The digital system had a dynamic range of 9.9 +/- 1.8, which was wider than the film-screen system (p<0.02). The dynamic range of the film-screen system was limited by the dynamic range of the film. The digital detector, on the other hand, had an estimated dynamic range of 42, which was wider than the dynamic range of the digital system in its entirety by a factor of 4. The generator/tube combination was the limiting factor in determining the digital system's dynamic range.

A Lower-Cost High-Resolution LYSO Detector Development for Positron Emission Mammography (PEM)

PubMed Central

Ramirez, Rocio A.; Zhang, Yuxuan; Liu, Shitao; Li, Hongdi; Baghaei, Hossain; An, Shaohui; Wang, Chao; Jan, Meei-Ling; Wong, Wai-Hoi

2010-01-01

In photomultiplier-quadrant-sharing (PQS) geometry for positron emission tomography applications, each PMT is shared by four blocks and each detector block is optically coupled to four round PMTs. Although this design reduces the cost of high-resolution PET systems, when the camera consists of detector panels that are made up of square blocks, half of the PMT’s sensitive window remains unused at the detector panel edge. Our goal was to develop a LYSO detector panel which minimizes the unused portion of the PMTs for a low-cost, high-resolution, and high-sensitivity positron emission mammography (PEM) camera. We modified the PQS design by using elongated blocks at panel edges and square blocks in the inner area. For elongated blocks, symmetric and asymmetrical reflector patterns were developed and PQS and PMT-half-sharing (PHS) arrangements were implemented in order to obtain a suitable decoding. The packing fraction was 96.3% for asymmetric block and 95.5% for symmetric block. Both of the blocks have excellent decoding capability with all crystals clearly identified, 156 for asymmetric and 144 for symmetric and peak-to-valley ratio of 3.0 and 2.3 respectively. The average energy resolution was 14.2% for the asymmetric block and 13.1% for the symmetric block. Using a modified PQS geometry and asymmetric block design, we reduced the unused PMT region at detector panel edges, thereby increased the field-of-view and the overall detection sensitivity and minimized the undetected breast region near the chest wall. This detector design and using regular round PMT allowed building a lower-cost, high-resolution and high-sensitivity PEM camera. PMID:20485510

Nanowire-based detector

DOEpatents

Berggren, Karl K; Hu, Xiaolong; Masciarelli, Daniele

2014-06-24

Systems, articles, and methods are provided related to nanowire-based detectors, which can be used for light detection in, for example, single-photon detectors. In one aspect, a variety of detectors are provided, for example one including an electrically superconductive nanowire or nanowires constructed and arranged to interact with photons to produce a detectable signal. In another aspect, fabrication methods are provided, including techniques to precisely reproduce patterns in subsequently formed layers of material using a relatively small number of fabrication steps. By precisely reproducing patterns in multiple material layers, one can form electrically insulating materials and electrically conductive materials in shapes such that incoming photons are redirected toward a nearby electrically superconductive materials (e.g., electrically superconductive nanowire(s)). For example, one or more resonance structures (e.g., comprising an electrically insulating material), which can trap electromagnetic radiation within its boundaries, can be positioned proximate the nanowire(s). The resonance structure can include, at its boundaries, electrically conductive material positioned proximate the electrically superconductive nanowire such that light that would otherwise be transmitted through the sensor is redirected toward the nanowire(s) and detected. In addition, electrically conductive material can be positioned proximate the electrically superconductive nanowire (e.g. at the aperture of the resonant structure), such that light is directed by scattering from this structure into the nanowire.

High resolution micro-CT of low attenuating organic materials using large area photon-counting detector

NASA Astrophysics Data System (ADS)

Kumpová, I.; Vavřík, D.; Fíla, T.; Koudelka, P.; Jandejsek, I.; Jakůbek, J.; Kytýř, D.; Zlámal, P.; Vopálenský, M.; Gantar, A.

2016-02-01

To overcome certain limitations of contemporary materials used for bone tissue engineering, such as inflammatory response after implantation, a whole new class of materials based on polysaccharide compounds is being developed. Here, nanoparticulate bioactive glass reinforced gelan-gum (GG-BAG) has recently been proposed for the production of bone scaffolds. This material offers promising biocompatibility properties, including bioactivity and biodegradability, with the possibility of producing scaffolds with directly controlled microgeometry. However, to utilize such a scaffold with application-optimized properties, large sets of complex numerical simulations using the real microgeometry of the material have to be carried out during the development process. Because the GG-BAG is a material with intrinsically very low attenuation to X-rays, its radiographical imaging, including tomographical scanning and reconstructions, with resolution required by numerical simulations might be a very challenging task. In this paper, we present a study on X-ray imaging of GG-BAG samples. High-resolution volumetric images of investigated specimens were generated on the basis of micro-CT measurements using a large area flat-panel detector and a large area photon-counting detector. The photon-counting detector was composed of a 010× 1 matrix of Timepix edgeless silicon pixelated detectors with tiling based on overlaying rows (i.e. assembled so that no gap is present between individual rows of detectors). We compare the results from both detectors with the scanning electron microscopy on selected slices in transversal plane. It has been shown that the photon counting detector can provide approx. 3× better resolution of the details in low-attenuating materials than the integrating flat panel detectors. We demonstrate that employment of a large area photon counting detector is a good choice for imaging of low attenuating materials with the resolution sufficient for numerical simulations.

SU-D-204-05: Quantitative Comparison of a High Resolution Micro-Angiographic Fluoroscopic (MAF) Detector with a Standard Flat Panel Detector (FPD) Using the New Metric of Generalized Measured Relative Object Detectability (GM-ROD)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russ, M; Ionita, C; Bednarek, D

Purpose: In endovascular image-guided neuro-interventions, visualization of fine detail is paramount. For example, the ability of the interventionist to visualize the stent struts depends heavily on the x-ray imaging detector performance. Methods: A study to examine the relative performance of the high resolution MAF-CMOS (pixel size 75µm, Nyquist frequency 6.6 cycles/mm) and a standard Flat Panel Detector (pixel size 194µm, Nyquist frequency 2.5 cycles/mm) detectors in imaging a neuro stent was done using the Generalized Measured Relative Object Detectability (GM-ROD) metric. Low quantum noise images of a deployed stent were obtained by averaging 95 frames obtained by both detectors withoutmore » changing other exposure or geometric parameters. The square of the Fourier transform of each image is taken and divided by the generalized normalized noise power spectrum to give an effective measured task-specific signal-to-noise ratio. This expression is then integrated from 0 to each of the detector’s Nyquist frequencies, and the GM-ROD value is determined by taking a ratio of the integrals for the MAF-CMOS to that of the FPD. The lower bound of integration can be varied to emphasize high frequencies in the detector comparisons. Results: The MAF-CMOS detector exhibits vastly superior performance over the FPD when integrating over all frequencies, yielding a GM-ROD value of 63.1. The lower bound of integration was stepped up in increments of 0.5 cycles/mm for higher frequency comparisons. As the lower bound increased, the GM-ROD value was augmented, reflecting the superior performance of the MAF-CMOS in the high frequency regime. Conclusion: GM-ROD is a versatile metric that can provide quantitative detector and task dependent comparisons that can be used as a basis for detector selection. Supported by NIH Grant: 2R01EB002873 and an equipment grant from Toshiba Medical Systems Corporation.« less

Experimental flat-panel high-spatial-resolution volume CT of the temporal bone.

PubMed

Gupta, Rajiv; Bartling, Soenke H; Basu, Samit K; Ross, William R; Becker, Hartmut; Pfoh, Armin; Brady, Thomas; Curtin, Hugh D

2004-09-01

A CT scanner employing a digital flat-panel detector is capable of very high spatial resolution as compared with a multi-section CT (MSCT) scanner. Our purpose was to determine how well a prototypical volume CT (VCT) scanner with a flat-panel detector system defines fine structures in temporal bone. Four partially manipulated temporal-bone specimens were imaged by use of a prototypical cone-beam VCT scanner with a flat-panel detector system at an isometric resolution of 150 microm at the isocenter. These specimens were also depicted by state-of-the-art multisection CT (MSCT). Forty-two structures imaged by both scanners were qualitatively assessed and rated, and scores assigned to VCT findings were compared with those of MSCT. Qualitative assessment of anatomic structures, lesions, cochlear implants, and middle-ear hearing aids indicated that image quality was significantly better with VCT (P < .001). Structures near the spatial-resolution limit of MSCT (e.g., bony covering of the tympanic segment of the facial canal, the incudo-stapedial joint, the proximal vestibular aqueduct, the interscalar septum, and the modiolus) had higher contrast and less partial-volume effect with VCT. The flat-panel prototype provides better definition of fine osseous structures of temporal bone than that of currently available MSCT scanners. This study provides impetus for further research in increasing spatial resolution beyond that offered by the current state-of-the-art scanners.

Experiences with radiation portal detectors for international rail transport

NASA Astrophysics Data System (ADS)

Stromswold, D. C.; McCormick, K.; Todd, L.; Ashbaker, E. D.; Evans, J. C.

2006-08-01

Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm × 10-cm × 41-cm) and a PVT panel with a 41 cm × 173 cm × 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars creates a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site, the trains carried inter-modal containers that had been unloaded from ships, and at the other site, the trains contained bulk cargo in tanker cars and hopper cars or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting portion of the program GADRAS developed at Sandia National Laboratories. For most of the NORM, the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases.

Reference-based phasing using the Haplotype Reference Consortium panel.

PubMed

Loh, Po-Ru; Danecek, Petr; Palamara, Pier Francesco; Fuchsberger, Christian; A Reshef, Yakir; K Finucane, Hilary; Schoenherr, Sebastian; Forer, Lukas; McCarthy, Shane; Abecasis, Goncalo R; Durbin, Richard; L Price, Alkes

2016-11-01

Haplotype phasing is a fundamental problem in medical and population genetics. Phasing is generally performed via statistical phasing in a genotyped cohort, an approach that can yield high accuracy in very large cohorts but attains lower accuracy in smaller cohorts. Here we instead explore the paradigm of reference-based phasing. We introduce a new phasing algorithm, Eagle2, that attains high accuracy across a broad range of cohort sizes by efficiently leveraging information from large external reference panels (such as the Haplotype Reference Consortium; HRC) using a new data structure based on the positional Burrows-Wheeler transform. We demonstrate that Eagle2 attains a ∼20× speedup and ∼10% increase in accuracy compared to reference-based phasing using SHAPEIT2. On European-ancestry samples, Eagle2 with the HRC panel achieves >2× the accuracy of 1000 Genomes-based phasing. Eagle2 is open source and freely available for HRC-based phasing via the Sanger Imputation Service and the Michigan Imputation Server.

Thermal control of the GRASP detector section

NASA Astrophysics Data System (ADS)

Roig, P. B.

1988-12-01

The necessity of keeping GRASP telescope (Gamma Ray Astronomy with Spectroscopy and Positioning) detectors at working temperatures within an adequate range (85 + or - 15 K for the germanium and 283 + or - 20 K for CsI) is discussed. Thermal control based in cryogenic liquid tanks is not considered the most suitable solution because of mass and lifetime considerations. Instead of this conventional solution, a concept using a combination of passive and active cooling systems was chosen. It combines the features of a corrugated radiator panel, thermal shields, MLI blankets, and an extra cooling system based on the Stirling cycle engine.

Fatigue behavior of wood-fiber-based tri-axial engineered sandwich composite panels (ESCP)

Treesearch

Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

2015-01-01

The static and fatigue bending behavior of wood-fiber-based tri-axial engineered sandwich composite panels (ESCP) has been investigated by four-point bending tests. Fatigue panels and weakened panels (wESCP) with an initial interface defect were manufactured for the fatigue tests. Stress σ vs. number of cycles curves (S-N) were recorded under the different stress...

Characterizing X-ray detectors for prototype digital breast tomosynthesis systems

NASA Astrophysics Data System (ADS)

Kim, Y.-s.; Park, H.-s.; Park, S.-J.; Choi, S.; Lee, H.; Lee, D.; Choi, Y.-W.; Kim, H.-J.

2016-03-01

The digital breast tomosynthesis (DBT) system is a newly developed 3-D imaging technique that overcomes the tissue superposition problems of conventional mammography. Therefore, it produces fewer false positives. In DBT system, several parameters are involved in image acquisition, including geometric components. A series of projections should be acquired at low exposure. This makes the system strongly dependent on the detector's characteristic performance. This study compares two types of x-ray detectors developed by the Korea Electrotechnology Research Institute (KERI). The first prototype DBT system has a CsI (Tl) scintillator/CMOS based flat panel digital detector (2923 MAM, Dexela Ltd.), with a pixel size of 0.0748 mm. The second uses a-Se based direct conversion full field detector (AXS 2430, analogic) with a pixel size of 0.085 mm. The geometry of both systems is same, with a focal spot 665.8 mm from the detector, and a center of rotation 33 mm above the detector surface. The systems were compared with regard to modulation transfer function (MTF), normalized noise power spectrum (NNPS), detective quantum efficiency (DQE) and a new metric, the relative object detectability (ROD). The ROD quantifies the relative performance of each detector at detecting specified objects. The system response function demonstrated excellent linearity (R2>0.99). The CMOS-based detector had a high sensitivity, while the Anrad detector had a large dynamic range. The higher MTF and noise power spectrum (NPS) values were measured using an Anrad detector. The maximum DQE value of the Dexela detector was higher than that of the Anrad detector with a low exposure level, considering one projection exposure for tomosynthesis. Overall, the Dexela detector performed better than did the Anrad detector with regard to the simulated Al wires, spheres, test objects of ROD with low exposure level. In this study, we compared the newly developed prototype DBT system with two different types of x

Photoacoustic-based detector for infrared laser spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholz, L.; Palzer, S., E-mail: stefan.palzer@imtek.uni-freiburg.de

In this contribution, we present an alternative detector technology for use in direct absorption spectroscopy setups. Instead of a semiconductor based detector, we use the photoacoustic effect to gauge the light intensity. To this end, the target gas species is hermetically sealed under excess pressure inside a miniature cell along with a MEMS microphone. Optical access to the cell is provided by a quartz window. The approach is particularly suitable for tunable diode laser spectroscopy in the mid-infrared range, where numerous molecules exhibit large absorption cross sections. Moreover, a frequency standard is integrated into the method since the number densitymore » and pressure inside the cell are constant. We demonstrate that the information extracted by our method is at least equivalent to that achieved using a semiconductor-based photon detector. As exemplary and highly relevant target gas, we have performed direct spectroscopy of methane at the R3-line of the 2v{sub 3} band at 6046.95 cm{sup −1} using both detector technologies in parallel. The results may be transferred to other infrared-active transitions without loss of generality.« less

Theoretical and Monte Carlo optimization of a stacked three-layer flat-panel x-ray imager for applications in multi-spectral diagnostic medical imaging

NASA Astrophysics Data System (ADS)

Lopez Maurino, Sebastian; Badano, Aldo; Cunningham, Ian A.; Karim, Karim S.

2016-03-01

We propose a new design of a stacked three-layer flat-panel x-ray detector for dual-energy (DE) imaging. Each layer consists of its own scintillator of individual thickness and an underlying thin-film-transistor-based flat-panel. Three images are obtained simultaneously in the detector during the same x-ray exposure, thereby eliminating any motion artifacts. The detector operation is two-fold: a conventional radiography image can be obtained by combining all three layers' images, while a DE subtraction image can be obtained from the front and back layers' images, where the middle layer acts as a mid-filter that helps achieve spectral separation. We proceed to optimize the detector parameters for two sample imaging tasks that could particularly benefit from this new detector by obtaining the best possible signal to noise ratio per root entrance exposure using well-established theoretical models adapted to fit our new design. These results are compared to a conventional DE temporal subtraction detector and a single-shot DE subtraction detector with a copper mid-filter, both of which underwent the same theoretical optimization. The findings are then validated using advanced Monte Carlo simulations for all optimized detector setups. Given the performance expected from initial results and the recent decrease in price for digital x-ray detectors, the simplicity of the three-layer stacked imager approach appears promising to usher in a new generation of multi-spectral digital x-ray diagnostics.

Radiation detector system having heat pipe based cooling

DOEpatents

Iwanczyk, Jan S.; Saveliev, Valeri D.; Barkan, Shaul

2006-10-31

A radiation detector system having a heat pipe based cooling. The radiation detector system includes a radiation detector thermally coupled to a thermo electric cooler (TEC). The TEC cools down the radiation detector, whereby heat is generated by the TEC. A heat removal device dissipates the heat generated by the TEC to surrounding environment. A heat pipe has a first end thermally coupled to the TEC to receive the heat generated by the TEC, and a second end thermally coupled to the heat removal device. The heat pipe transfers the heat generated by the TEC from the first end to the second end to be removed by the heat removal device.

Targeted therapy according to next generation sequencing-based panel sequencing.

PubMed

Saito, Motonobu; Momma, Tomoyuki; Kono, Koji

2018-04-17

Targeted therapy against actionable gene mutations shows a significantly higher response rate as well as longer survival compared to conventional chemotherapy, and has become a standard therapy for many cancers. Recent progress in next-generation sequencing (NGS) has enabled to identify huge number of genetic aberrations. Based on sequencing results, patients recommend to undergo targeted therapy or immunotherapy. In cases where there are no available approved drugs for the genetic mutations detected in the patients, it is recommended to be facilitate the registration for the clinical trials. For that purpose, a NGS-based sequencing panel that can simultaneously target multiple genes in a single investigation has been used in daily clinical practice. To date, various types of sequencing panels have been developed to investigate genetic aberrations with tumor somatic genome variants (gain-of-function or loss-of-function mutations, high-level copy number alterations, and gene fusions) through comprehensive bioinformatics. Because sequencing panels are efficient and cost-effective, they are quickly being adopted outside the lab, in hospitals and clinics, in order to identify personal targeted therapy for individual cancer patients.

Design of FPGA-based radiation tolerant quench detectors for LHC

NASA Astrophysics Data System (ADS)

Steckert, J.; Skoczen, A.

2017-04-01

The Large Hadron Collider (LHC) comprises many superconducting circuits. Most elements of these circuits require active protection. The functionality of the quench detectors was initially implemented as microcontroller based equipment. After the initial stage of the LHC operation with beams the introduction of a new type of quench detector began. This article presents briefly the main ideas and architectures applied to the design and the validation of FPGA-based quench detectors.

Topological detector: measuring continuous dosimetric quantities with few-element detector array.

PubMed

Han, Zhaohui; Brivio, Davide; Sajo, Erno; Zygmanski, Piotr

2016-08-21

A prototype topological detector was fabricated and investigated for quality assurance of radiation producing medical devices. Unlike a typical array or flat panel detector, a topological detector, while capable of achieving a very high spatial resolution, consists of only a few elements and therefore is much simpler in construction and more cost effective. The key feature allowing this advancement is a geometry-driven design that is customized for a specific dosimetric application. In the current work, a topological detector of two elements was examined for the positioning verification of the radiation collimating devices (jaws, MLCs, and blades etc). The detector was diagonally segmented from a rectangular thin film strip (2.5 cm  ×  15 cm), giving two contiguous but independent detector elements. The segmented area was the central portion of the strip measuring 5 cm in length. Under irradiation, signals from each detector element were separately digitized using a commercial multichannel data acquisition system. The center and size of an x-ray field, which were uniquely determined by the collimator positions, were shown mathematically to relate to the difference and sum of the two signals. As a proof of concept, experiments were carried out using slit x-ray fields ranging from 2 mm to 20 mm in size. It was demonstrated that, the collimator positions can be accurately measured with sub-millimeter precisions.

Novel infrared detector based on a tunneling displacement transducer

NASA Technical Reports Server (NTRS)

Kenny, T. W.; Kaiser, W. J.; Waltman, S. B.; Reynolds, J. K.

1991-01-01

The paper describes the design, fabrication, and characteristics of a novel infrared detector based on the principle of Golay's (1947) pneumatic infrared detector, which uses the expansion of a gas to detect infrared radiation. The present detector is constructed entirely from micromachined silicon and uses an electron tunneling displacement transducer for the detection of gas expansion. The sensitivity of the new detector is competitive with the best commercial pyroelectric sensors and can be readily improved by an order of magnitude through the use of an optimized transducer.

Flame Detector

NASA Technical Reports Server (NTRS)

1990-01-01

Scientific Instruments, Inc. has now developed a second generation, commercially available instrument to detect flames in hazardous environments, typically refineries, chemical plants and offshore drilling platforms. The Model 74000 detector incorporates a sensing circuit that detects UV radiation in a 100 degree conical field of view extending as far as 250 feet from the instrument. It operates in a bandwidth that makes it virtually 'blind' to solar radiation while affording extremely high sensitivity to ultraviolet flame detection. A 'windowing' technique accurately discriminates between background UV radiation and ultraviolet emitted from an actual flame, hence the user is assured of no false alarms. Model 7410CP is a combination controller and annunciator panel designed to monitor and control as many as 24 flame detectors. *Model 74000 is no longer being manufactured.

Development of a fast multi-line x-ray CT detector for NDT

NASA Astrophysics Data System (ADS)

Hofmann, T.; Nachtrab, F.; Schlechter, T.; Neubauer, H.; Mühlbauer, J.; Schröpfer, S.; Ernst, J.; Firsching, M.; Schweiger, T.; Oberst, M.; Meyer, A.; Uhlmann, N.

2015-04-01

Typical X-ray detectors for non-destructive testing (NDT) are line detectors or area detectors, like e.g. flat panel detectors. Multi-line detectors are currently only available in medical Computed Tomography (CT) scanners. Compared to flat panel detectors, line and multi-line detectors can achieve much higher frame rates. This allows time-resolved 3D CT scans of an object under investigation. Also, an improved image quality can be achieved due to reduced scattered radiation from object and detector themselves. Another benefit of line and multi-line detectors is that very wide detectors can be assembled easily, while flat panel detectors are usually limited to an imaging field with a size of approx. 40 × 40 cm2 at maximum. The big disadvantage of line detectors is the limited number of object slices that can be scanned simultaneously. This leads to long scan times for large objects. Volume scans with a multi-line detector are much faster, but with almost similar image quality. Due to the promising properties of multi-line detectors their application outside of medical CT would also be very interesting for NDT. However, medical CT multi-line detectors are optimized for the scanning of human bodies. Many non-medical applications require higher spatial resolutions and/or higher X-ray energies. For those non-medical applications we are developing a fast multi-line X-ray detector.In the scope of this work, we present the current state of the development of the novel detector, which includes several outstanding properties like an adjustable curved design for variable focus-detector-distances, conserving nearly uniform perpendicular irradiation over the entire detector width. Basis of the detector is a specifically designed, radiation hard CMOS imaging sensor with a pixel pitch of 200 μ m. Each pixel has an automatic in-pixel gain adjustment, which allows for both: a very high sensitivity and a wide dynamic range. The final detector is planned to have 256 lines of

The MPGD-based photon detectors for the upgrade of COMPASS RICH-1

NASA Astrophysics Data System (ADS)

Alexeev, M.; Azevedo, C. D. R.; Birsa, R.; Bradamante, F.; Bressan, A.; Büchele, M.; Chiosso, M.; Ciliberti, P.; Dalla Torre, S.; Dasgupta, S.; Denisov, O.; Finger, M.; Finger, M.; Fischer, H.; Gobbo, B.; Gregori, M.; Hamar, G.; Herrmann, F.; Levorato, S.; Maggiora, A.; Makke, A.; Martin, A.; Menon, G.; Steiger, K.; Novy, J.; Panzieri, D.; Pereira, F. A. B.; Santos, C. A.; Sbrizzai, G.; Schopferer, S.; Slunecka, M.; Steiger, L.; Sulc, M.; Tessarotto, F.; Veloso, J. F. C. A.

2017-12-01

The RICH-1 Detector of the COMPASS experiment at CERN SPS has undergone an important upgrade for the 2016 physics run. Four new photon detectors, based on Micro Pattern Gaseous Detector technology and covering a total active area larger than 1.2 m2 have replaced the previously used MWPC-based photon detectors. The upgrade answers the challenging efficiency and stability quest for the new phase of the COMPASS spectrometer physics programme. The new detector architecture consists in a hybrid MPGD combination of two Thick Gas Electron Multipliers and a MicroMegas stage. Signals, extracted from the anode pad by capacitive coupling, are read-out by analog F-E based on the APV25 chip. The main aspects of the COMPASS RICH-1 photon detectors upgrade are presented focussing on detector design, engineering aspects, mass production, the quality assessment and assembly challenges of the MPGD components. The status of the detector commissioning is also presented.

AAPM/RSNA physics tutorial for residents: physics of flat-panel fluoroscopy systems: Survey of modern fluoroscopy imaging: flat-panel detectors versus image intensifiers and more.

PubMed

Nickoloff, Edward Lee

2011-01-01

This article reviews the design and operation of both flat-panel detector (FPD) and image intensifier fluoroscopy systems. The different components of each imaging chain and their functions are explained and compared. FPD systems have multiple advantages such as a smaller size, extended dynamic range, no spatial distortion, and greater stability. However, FPD systems typically have the same spatial resolution for all fields of view (FOVs) and are prone to ghosting. Image intensifier systems have better spatial resolution with the use of smaller FOVs (magnification modes) and tend to be less expensive. However, the spatial resolution of image intensifier systems is limited by the television system to which they are coupled. Moreover, image intensifier systems are degraded by glare, vignetting, spatial distortions, and defocusing effects. FPD systems do not have these problems. Some recent innovations to fluoroscopy systems include automated filtration, pulsed fluoroscopy, automatic positioning, dose-area product meters, and improved automatic dose rate control programs. Operator-selectable features may affect both the patient radiation dose and image quality; these selectable features include dose level setting, the FOV employed, fluoroscopic pulse rates, geometric factors, display software settings, and methods to reduce the imaging time. © RSNA, 2011.

Fiber optic thermal/fast neutron and gamma ray scintillation detector

DOEpatents

Neal, John S.; Mihalczo, John T.

2006-11-28

A detector system that combines a .sup.6Li loaded glass fiber scintillation thermal neutron detector with a fast scintillation detector in a single layered structure. Detection of thermal and fast neutrons and ionizing electromagnetic radiation is achieved in the unified detector structure. The fast scintillator replaces the polyethelene moderator layer adjacent the .sup.6Li loaded glass fiber panel of the neutron detector and acts as the moderator for the glass fibers. Fast neutrons, x-rays and gamma rays are detected in the fast scintillator. Thermal neutrons, x-rays and gamma rays are detected in the glass fiber scintillator.

Gain and offset calibration reduces variation in exposure-dependent SNR among systems with identical digital flat-panel detectors.

PubMed

Willis, Charles E; Vinogradskiy, Yevgeniy Y; Lofton, Brad K; White, R Allen

2011-07-01

The conditions under which vendor performance criteria for digital radiography systems are obtained do not adequately simulate the conditions of actual clinical imaging with respect to radiographic technique factors, scatter production, and scatter control. Therefore, the relationship between performance under ideal conditions and performance in clinical practice remains unclear. Using data from a large complement of systems in clinical use, the authors sought to develop a method to establish expected performance criteria for digital flat-panel radiography systems with respect to signal-to-noise ratio (SNR) versus detector exposure under clinical conditions for thoracic imaging. The authors made radiographic exposures of a patient-equivalent chest phantom at 125 kVp and 180 cm source-to-image distance. The mAs value was modified to produce exposures above and below the mAs delivered by automatic exposure control. Exposures measured free-in-air were corrected to the imaging plane by the inverse square law, by the attenuation factor of the phantom, and by the Bucky factor of the grid for the phantom, geometry, and kilovolt peak. SNR was evaluated as the ratio of the mean to the standard deviation (SD) of a region of interest automatically selected in the center of each unprocessed image. Data were acquired from 18 systems, 14 of which were tested both before and after gain and offset calibration. SNR as a function of detector exposure was interpolated using a double logarithmic function to stratify the data into groups of 0.2, 0.5, 1.0, 2.0, and 5.0 mR exposure (1.8, 4.5, 9.0, 18, and 45 microGy air KERMA) to the detector. The mean SNR at each exposure interval after calibration exhibited linear dependence on the mean SNR before calibration (r2=0.9999). The dependence was greater than unity (m = 1.101 +/- 0.006), and the difference from unity was statistically significant (p <0.005). The SD of mean SNR after calibration also exhibited linear dependence on the SD of

Optical detectors based on thermoelastic effect in crystalline quartz

NASA Astrophysics Data System (ADS)

Chelibanov, V. P.; Ishanin, G. G.

2015-06-01

Optical detectors developed on base of thermo elastic effect In quartz crystalline (PTEK) attributed to the thermal detectors group. Such detectors occurred very effective for the registration of pulsed light energy or power of harmonically modulated laser radiation flux in a wide spectral (from UV to far IR) and dynamic ranges (from 10-6 to 300 W / cm2 with cooling) with a time constant up to10-6 seconds. When exposed to electromagnetic radiation occurs at the receiver thermal field which causes mechanical stress in the transient crystalline quartz, which in turn leads to a change in the polarization of crystalline quartz and, as a consequence, to an electric potential difference at the electrodes (the front surface with a conductive coating and damper). The capacitive characteristic of the detector, based on a thermo elastic effect in crystalline quartz, eliminates the possibility of working with constant flow of radiation, which also affects at the frequency response of the detector, since the potential difference appearance in the piezoelectric plate depends on the direction of the forces relative to the axes X, Y, Z of the crystal. Therefore, a certain choice of orientation of the receiving element is necessary in accordance with the physical properties of crystalline quartz. In this paper, a calculation of the sensitivity and frequency characteristics of optical detectors based on the thermo elastic effect in crystalline quartz at the harmonic effects of electromagnetic radiation flux are reported.

Dynamic flat panel detector versus image intensifier in cardiac imaging: dose and image quality

NASA Astrophysics Data System (ADS)

Vano, E.; Geiger, B.; Schreiner, A.; Back, C.; Beissel, J.

2005-12-01

The practical aspects of the dosimetric and imaging performance of a digital x-ray system for cardiology procedures were evaluated. The system was configured with an image intensifier (II) and later upgraded to a dynamic flat panel detector (FD). Entrance surface air kerma (ESAK) to phantoms of 16, 20, 24 and 28 cm of polymethyl methacrylate (PMMA) and the image quality of a test object were measured. Images were evaluated directly on the monitor and with numerical methods (noise and signal-to-noise ratio). Information contained in the DICOM header for dosimetry audit purposes was also tested. ESAK values per frame (or kerma rate) for the most commonly used cine and fluoroscopy modes for different PMMA thicknesses and for field sizes of 17 and 23 cm for II, and 20 and 25 cm for FD, produced similar results in the evaluated system with both technologies, ranging between 19 and 589 µGy/frame (cine) and 5 and 95 mGy min-1 (fluoroscopy). Image quality for these dose settings was better for the FD version. The 'study dosimetric report' is comprehensive, and its numerical content is sufficiently accurate. There is potential in the future to set those systems with dynamic FD to lower doses than are possible in the current II versions, especially for digital cine runs, or to benefit from improved image quality.

24. INTERIOR OF CENTRAL ROOM. BASE POWER PANEL VISIBLE ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. INTERIOR OF CENTRAL ROOM. BASE POWER PANEL VISIBLE ON RIGHT WALL OF HALLWAY. - Chollas Heights Naval Radio Transmitting Facility, Transmitter Building, 6410 Zero Road, San Diego, San Diego County, CA

Cone-Beam CT with a Flat-Panel Detector: From Image Science to Image-Guided Surgery

PubMed Central

Siewerdsen, Jeffrey H.

2011-01-01

The development of large-area flat-panel x-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions - for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck / skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical

Primary Care Physician Panel Size and Quality of Care: A Population-Based Study in Ontario, Canada.

PubMed

Dahrouge, Simone; Hogg, William; Younger, Jaime; Muggah, Elizabeth; Russell, Grant; Glazier, Richard H

2016-01-01

The purpose of this study was to determine the relationship between the number of patients under a primary care physician's care (panel size) and primary care quality indicators. We conducted a cross-sectional, population-based study of fee-for-service and capitated interprofessional and non-interprofessional primary health care practices in Ontario, Canada between April 2008 and March 2010, encompassing 4,195 physicians with panel sizes ≥1,200 serving 8.3 million patients. Data was extracted from multiple linked, health-related administrative databases and covered 16 quality indicators spanning 5 dimensions of care: access, continuity, comprehensiveness, and evidence-based indicators of cancer screening and chronic disease management. The likelihood of being up-to-date on cervical, colorectal, and breast cancer screening showed relative decreases of 7.9% (P <.001), 5.9% (P = .01), and 4.6% (P <.001), respectively, with increasing panel size (from 1,200 to 3,900). Eight chronic care indicators (4 medication-based and 4 screening-based) showed no significant association with panel size. The likelihood of individuals with a new diagnosis of congestive heart failure having an echocardiogram, however, increased by a relative 8.1% (P <.001) with higher panel size. Increasing panel size was also associated with a 10.8% relative increase in hospitalization rates for ambulatory-care-sensitive conditions (P = .04) and a 10.8% decrease in non-urgent emergency department visits (P = .004). Continuity was highest with medium panel sizes (P <.001), and comprehensiveness had a small decrease (P = .03) with increasing panel size. Increasing panel size was associated with small decreases in cancer screening, continuity, and comprehensiveness, but showed no consistent relationships with chronic disease management or access indicators. We found no panel size threshold above which quality of care suffered. © 2016 Annals of Family Medicine, Inc.

Fission-fragment detector for DANCE based on thin scintillating films

NASA Astrophysics Data System (ADS)

Rusev, G.; Roman, A. R.; Daum, J. K.; Springs, R. K.; Bond, E. M.; Jandel, M.; Baramsai, B.; Bredeweg, T. A.; Couture, A.; Favalli, A.; Ianakiev, K. D.; Iliev, M. L.; Mosby, S.; Ullmann, J. L.; Walker, C. L.

2015-12-01

A fission-fragment detector based on thin scintillating films has been built to serve as a trigger/veto detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing 4 π detection of the fission fragments. The scintillation photons were registered with silicon photomultipliers. A measurement of the 235U (n , f) reaction with this detector at DANCE revealed a correct time-of-flight spectrum and provided an estimate for the efficiency of the prototype detector of 11.6(7)%. Design and test measurements with the detector are described.

Using Panel Vendors for Recruitment Into a Web-Based Family Prevention Program: Methodological Considerations.

PubMed

Wang-Schweig, Meme; Miller, Brenda A; Buller, David B; Byrnes, Hilary F; Bourdeau, Beth; Rogers, Veronica

2017-01-01

Use of online panel vendors in research has grown over the past decade. Panel vendors are organizations that recruit participants into a panel to take part in web-based surveys and match panelists to a target audience for data collection. We used two panel vendors to recruit families ( N = 411) with a 16- to 17-year-old teen to participate in a randomized control trial (RCT) of an online family-based program to prevent underage drinking and risky sexual behaviors. Our article addresses the following research questions: (1) How well do panel vendors provide a sample of families who meet our inclusion criteria to participate in a RCT? (2) How well do panel vendors provide a sample of families who reflect the characteristics of the general population? and (3) Does the choice of vendor influence the characteristics of families that we engage in research? Despite the screening techniques used by the panel vendors to identify families who met our inclusion criteria, 23.8% were found ineligible when research staff verified their eligibility by direct telephone contact. Compared to the general U.S. population, our sample had more Whites and more families with higher education levels. Finally, across the two panel vendors, there were no significant differences in the characteristics of families, except for mean age. The online environment provides opportunities for new methods to recruit participants in research studies. However, innovative recruitment methods need careful study to ensure the quality of their samples.

Interactive display system having a matrix optical detector

DOEpatents

Veligdan, James T.; DeSanto, Leonard

2007-01-23

A display system includes a waveguide optical panel having an inlet face and an opposite outlet face. An image beam is projected across the inlet face laterally and transversely for display on the outlet face. An optical detector including a matrix of detector elements is optically aligned with the inlet face for detecting a corresponding lateral and transverse position of an inbound light spot on the outlet face.

Psychophysical evaluation of the image quality of a dynamic flat-panel digital x-ray image detector using the threshold contrast detail detectability (TCDD) technique

NASA Astrophysics Data System (ADS)

Davies, Andrew G.; Cowen, Arnold R.; Bruijns, Tom J. C.

1999-05-01

We are currently in an era of active development of the digital X-ray imaging detectors that will serve the radiological communities in the new millennium. The rigorous comparative physical evaluations of such devices are therefore becoming increasingly important from both the technical and clinical perspectives. The authors have been actively involved in the evaluation of a clinical demonstration version of a flat-panel dynamic digital X-ray image detector (or FDXD). Results of objective physical evaluation of this device have been presented elsewhere at this conference. The imaging performance of FDXD under radiographic exposure conditions have been previously reported, and in this paper a psychophysical evaluation of the FDXD detector operating under continuous fluoroscopic conditions is presented. The evaluation technique employed was the threshold contrast detail detectability (TCDD) technique, which enables image quality to be measured on devices operating in the clinical environment. This approach addresses image quality in the context of both the image acquisition and display processes, and uses human observers to measure performance. The Leeds test objects TO[10] and TO[10+] were used to obtain comparative measurements of performance on the FDXD and two digital spot fluorography (DSF) systems, one utilizing a Plumbicon camera and the other a state of the art CCD camera. Measurements were taken at a range of detector entrance exposure rates, namely 6, 12, 25 and 50 (mu) R/s. In order to facilitate comparisons between the systems, all fluoroscopic image processing such as noise reduction algorithms, were disabled during the experiments. At the highest dose rate FDXD significantly outperformed the DSF comparison systems in the TCDD comparisons. At 25 and 12 (mu) R/s all three-systems performed in an equivalent manner and at the lowest exposure rate FDXD was inferior to the two DSF systems. At standard fluoroscopic exposures, FDXD performed in an equivalent

Digital subtraction angiography during transjugular intrahepatic portosystemic shunt creation or revision: data on radiation exposure and image quality obtained using a standard and a low-dose acquisition protocol in a flat-panel detector-based system.

PubMed

Miraglia, Roberto; Maruzzelli, Luigi; Cortis, Kelvin; Tafaro, Corrado; Gerasia, Roberta; Parisi, Carmelo; Luca, Angelo

2015-08-01

To determine whether the use of a low-dose acquisition protocol (LDP) in digital subtraction angiography during transjugular intrahepatic portosystemic shunt (TIPS) creation/revision results in significant reduction of patient radiation exposure and adequate image quality, as compared to a default reference standard-dose acquisition protocol (SDP). Two angiographic runs were performed during TIPS creation/revision: the first following catheterization of the portal venous system and the second after stent deployment/angioplasty. Constant field of view, object to image-detector distance, and source to image-receptor distance were maintained in each patient during the two angiographic runs. 17 consecutive adult patients who underwent TIPS creation (n = 11) or TIPS revision (n = 6) from December 2013 to March 2014 were considered eligible for this single centre prospective study. In each patient, the LDP and the SDP were used in a random order for the two runs, with each patient serving as his/her own control. The dose-area product (DAP) was calculated for each image and compared. Image quality was graded by two interventional radiologists other than the operator. In all runs acquired with the LDP, image quality was considered adequate for a successful procedural outcome. The DAP per image of the LDP was numerically inferior as compared to the DAP per image of the SDP in all patients. The mean reduction in DAP per image was 75.24% ± 5.7% (p < 0. 001). Radiation exposure during TIPS creation/revision was significantly reduced by selecting a LDP in our flat-panel detector-based system, while maintaining adequate image quality.

High-numerical-aperture-based virtual point detectors for photoacoustic tomography

NASA Astrophysics Data System (ADS)

Li, Changhui; Wang, Lihong V.

2008-07-01

The focal point of a high-numerical-aperture (NA) ultrasonic transducer can be used as a virtual point detector. This virtual point detector detects omnidirectionally over a wide acceptance angle. It also combines a large active transducer surface and a small effective virtual detector size. Thus the sensitivity is high compared with that of a real point detector, and the aperture effect is small compared with that of a finite size transducer. We present two kinds of high-NA-based virtual point detectors and their successful application in photoacoustic tomography. They can also be applied in other ultrasound-related fields.

Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2015-10-20

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2016-06-28

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Table-top phase-contrast imaging employing photon-counting detectors towards mammographic applications

NASA Astrophysics Data System (ADS)

Palma, K. D.; Pichotka, M.; Hasn, S.; Granja, C.

2017-02-01

In mammography the difficult task to detect microcalcifications (≈ 100 μm) and low contrast structures in the breast has been a topic of interest from its beginnings. The possibility to improve the image quality requires the effort to employ novel X-ray imaging techniques, such as phase-contrast, and high resolution detectors. Phase-contrast techniques are promising tools for medical diagnosis because they provide additional and complementary information to traditional absorption-based X-ray imaging methods. In this work a Hamamatsu microfocus X-ray source with tungsten anode and a photon counting detector (Timepix operated in Medipix mode) was used. A significant improvement in the detection of phase-effects using Medipix detector was observed in comparison to an standard flat-panel detector. An optimization of geometrical parameters reveals the dependency on the X-ray propagation path and the small angle deviation. The quantification of these effects was achieved taking into account the image noise, contrast, spatial resolution of the phase-enhancement, absorbed dose, and energy dependence.

Panel 5: Microbiology and Immunology Panel

PubMed Central

Murphy, Timothy F.; Chonmaitree, Tasnee; Barenkamp, Stephen; Kyd, Jennelle; Nokso-Koivisto, Johanna; Patel, Janak A.; Heikkinen, Terho; Yamanaka, Noboru; Ogra, Pearay; Swords, W. Edward; Sih, Tania; Pettigrew, Melinda M.

2014-01-01

Objective The objective is to perform a comprehensive review of the literature from January 2007 through June 2011 on the virology, bacteriology, and immunology related to otitis media. Data Sources PubMed database of the National Library of Medicine. Review Methods Three subpanels with co-chairs comprising experts in the virology, bacteriology, and immunology of otitis media were formed. Each of the panels reviewed the literature in their respective fields and wrote draft reviews. The reviews were shared with all panel members, and a second draft was created. The entire panel met at the 10th International Symposium on Recent Advances in Otitis Media in June 2011 and discussed the review and refined the content further. A final draft was created, circulated, and approved by the panel. Conclusion Excellent progress has been made in the past 4 years in advancing an understanding of the microbiology and immunology of otitis media. Advances include laboratory-based basic studies, cell-based assays, work in animal models, and clinical studies. Implications for Practice The advances of the past 4 years formed the basis of a series of short-term and long-term research goals in an effort to guide the field. Accomplishing these goals will provide opportunities for the development of novel interventions, including new ways to better treat and prevent otitis media. PMID:23536533

High-resolution extremity cone-beam CT with a CMOS detector: Task-based optimization of scintillator thickness.

PubMed

Cao, Q; Brehler, M; Sisniega, A; Stayman, J W; Yorkston, J; Siewerdsen, J H; Zbijewski, W

2017-03-01

CMOS x-ray detectors offer small pixel sizes and low electronic noise that may support the development of novel high-resolution imaging applications of cone-beam CT (CBCT). We investigate the effects of CsI scintillator thickness on the performance of CMOS detectors in high resolution imaging tasks, in particular in quantitative imaging of bone microstructure in extremity CBCT. A scintillator thickness-dependent cascaded systems model of CMOS x-ray detectors was developed. Detectability in low-, high- and ultra-high resolution imaging tasks (Gaussian with FWHM of ~250 μ m, ~80 μ m and ~40 μ m, respectively) was studied as a function of scintillator thickness using the theoretical model. Experimental studies were performed on a CBCT test bench equipped with DALSA Xineos3030 CMOS detectors (99 μ m pixels) with CsI scintillator thicknesses of 400 μ m and 700 μ m, and a 0.3 FS compact rotating anode x-ray source. The evaluation involved a radiographic resolution gauge (0.6-5.0 lp/mm), a 127 μm tungsten wire for assessment of 3D resolution, a contrast phantom with tissue-mimicking inserts, and an excised fragment of human tibia for visual assessment of fine trabecular detail. Experimental studies show ~35% improvement in the frequency of 50% MTF modulation when using the 400 μ m scintillator compared to the standard nominal CsI thickness of 700 μ m. Even though the high-frequency DQE of the two detectors is comparable, theoretical studies show a 14% to 28% increase in detectability index ( d' 2 ) of high- and ultrahigh resolution tasks, respectively, for the detector with 400 μ m CsI compared to 700 μ m CsI. Experiments confirm the theoretical findings, showing improvements with the adoption of 400 μ m panel in the visibility of the radiographic pattern (2× improvement in peak-to-through distance at 4.6 lp/mm) and a 12.5% decrease in the FWHM of the tungsten wire. Reconstructions of the tibial plateau reveal enhanced visibility of trabecular structures with

High-resolution extremity cone-beam CT with a CMOS detector: Task-based optimization of scintillator thickness

PubMed Central

Cao, Q.; Brehler, M.; Sisniega, A.; Stayman, J. W.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

2017-01-01

Purpose CMOS x-ray detectors offer small pixel sizes and low electronic noise that may support the development of novel high-resolution imaging applications of cone-beam CT (CBCT). We investigate the effects of CsI scintillator thickness on the performance of CMOS detectors in high resolution imaging tasks, in particular in quantitative imaging of bone microstructure in extremity CBCT. Methods A scintillator thickness-dependent cascaded systems model of CMOS x-ray detectors was developed. Detectability in low-, high- and ultra-high resolution imaging tasks (Gaussian with FWHM of ~250 μm, ~80 μm and ~40 μm, respectively) was studied as a function of scintillator thickness using the theoretical model. Experimental studies were performed on a CBCT test bench equipped with DALSA Xineos3030 CMOS detectors (99 μm pixels) with CsI scintillator thicknesses of 400 μm and 700 μm, and a 0.3 FS compact rotating anode x-ray source. The evaluation involved a radiographic resolution gauge (0.6–5.0 lp/mm), a 127 μm tungsten wire for assessment of 3D resolution, a contrast phantom with tissue-mimicking inserts, and an excised fragment of human tibia for visual assessment of fine trabecular detail. Results Experimental studies show ~35% improvement in the frequency of 50% MTF modulation when using the 400 μm scintillator compared to the standard nominal CsI thickness of 700 μm. Even though the high-frequency DQE of the two detectors is comparable, theoretical studies show a 14% to 28% increase in detectability index (d′2) of high- and ultrahigh resolution tasks, respectively, for the detector with 400 μm CsI compared to 700 μm CsI. Experiments confirm the theoretical findings, showing improvements with the adoption of 400 μm panel in the visibility of the radiographic pattern (2× improvement in peak-to-through distance at 4.6 lp/mm) and a 12.5% decrease in the FWHM of the tungsten wire. Reconstructions of the tibial plateau reveal enhanced visibility of trabecular

A scalable multi-photon coincidence detector based on superconducting nanowires.

PubMed

Zhu, Di; Zhao, Qing-Yuan; Choi, Hyeongrak; Lu, Tsung-Ju; Dane, Andrew E; Englund, Dirk; Berggren, Karl K

2018-06-04

Coincidence detection of single photons is crucial in numerous quantum technologies and usually requires multiple time-resolved single-photon detectors. However, the electronic readout becomes a major challenge when the measurement basis scales to large numbers of spatial modes. Here, we address this problem by introducing a two-terminal coincidence detector that enables scalable readout of an array of detector segments based on superconducting nanowire microstrip transmission line. Exploiting timing logic, we demonstrate a sixteen-element detector that resolves all 136 possible single-photon and two-photon coincidence events. We further explore the pulse shapes of the detector output and resolve up to four-photon events in a four-element device, giving the detector photon-number-resolving capability. This new detector architecture and operating scheme will be particularly useful for multi-photon coincidence detection in large-scale photonic integrated circuits.

Polarimetric subspace target detector for SAR data based on the Huynen dihedral model

NASA Astrophysics Data System (ADS)

Larson, Victor J.; Novak, Leslie M.

1995-06-01

Two new polarimetric subspace target detectors are developed based on a dihedral signal model for bright peaks within a spatially extended target signature. The first is a coherent dihedral target detector based on the exact Huynen model for a dihedral. The second is a noncoherent dihedral target detector based on the Huynen model with an extra unknown phase term. Expressions for these polarimetric subspace target detectors are developed for both additive Gaussian clutter and more general additive spherically invariant random vector clutter including the K-distribution. For the case of Gaussian clutter with unknown clutter parameters, constant false alarm rate implementations of these polarimetric subspace target detectors are developed. The performance of these dihedral detectors is demonstrated with real millimeter-wave fully polarimetric SAR data. The coherent dihedral detector which is developed with a more accurate description of a dihedral offers no performance advantage over the noncoherent dihedral detector which is computationally more attractive. The dihedral detectors do a better job of separating a set of tactical military targets from natural clutter compared to a detector that assumes no knowledge about the polarimetric structure of the target signal.

Report of the ultraviolet and visible sensors panel

NASA Technical Reports Server (NTRS)

Timothy, J. Gethyn; Blouke, M.; Bredthauer, R.; Kimble, R.; Lee, T.-H.; Lesser, M.; Siegmund, O.; Weckler, G.

1991-01-01

In order to meet the science objectives of the Astrotech 21 mission set the Ultraviolet (UV) and Visible Sensors Panel made a number of recommendations. In the UV wavelength range of 0.01 to 0.3 micro-m the focus is on the need for large format high quantum efficiency, radiation hard 'solar-blind' detectors. Options recommended for support include Si and non-Si charge coupled devices (CCDs) as well as photocathodes with improved microchannel plate readouts. For the 0.3 to 0.9 micro-m range, it was felt that Si CCDs offer the best option for high quantum efficiencies at these wavelengths. In the 0.9 to 2.5 micro-m the panel recommended support for the investigation of monolithic arrays. Finally, the panel noted that the implementation of very large arrays will require new data transmission, data recording, and data handling technologies.

Solar panel truss mounting systems and methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the basemore » rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.« less

A novel strategy to increase separated electron-hole dipoles in commercial Si based solar panel to assist photovoltaic effect

NASA Astrophysics Data System (ADS)

Feng, Yefeng; He, Cheng-En; Xu, Zhichao; Hu, Jianbing; Peng, Cheng

2018-01-01

Interface induced polarization has been found to have a significant impact on dielectric properties of 2-2 type polymer composites bearing Si based semi-conducting ceramic sheets. Inherent overall polarity of polymer layers in 2-2 composites has been verified to be closely connected with interface effect and achieved permittivity in composites. In present work, conducting performances of monocrystalline Si sheets coated by varied high polarity material layers were deeply researched. The positive results inspired us to propose a novel strategy to improve separated electron-hole dipoles in commercial Si based solar cell panel for assisting photovoltaic effect, based on strong interface induced polarization. Conducting features of solar panels coated by two different high polarity polymer layers were detected to be greatly elevated compared with solar panel standalone, thanks to interface induced polarization between panel and polymer. Polymer coating with higher polarity would lead to more separated electron-hole dipole pairs in solar panel contributing to higher conductivity of panel. Valid synergy of interface effect and photovoltaic effect was based on their unidirectional traits of electron transfer. Dielectric properties of solar panels in composites further confirmed that strategy. This work might provide a facile route to prepare promising Si based solar panels with higher photoelectric conversion efficiency by enhancing interface induced polarization between panel and polymer coating.

Paediatric emergency department-based carbon monoxide detector intervention: a randomised trial

PubMed Central

McKenzie, Lara B; Roberts, Kristin J; Kaercher, Roxanne M; Collins, Christy L; Comstock, R Dawn; Fernandez, Soledad; Abdel-Rasoul, Mahmoud; Casavant, Marcel J; Mihalov, Leslie

2017-01-01

Background Although non-fire-related carbon monoxide (CO) poisoning is almost entirely preventable, over 400 people die and 20 000 people are injured each year in the USA from unintentional CO poisoning. Thus, there is a critical need for evidence-based interventions for preventing CO poisoning and increasing the proper use and installation of CO detectors. Methods A randomised, controlled trial (Project CODE, a Carbon Monoxide Detector Education intervention) with 2-week and 6-month follow-up home observations was conducted in 299 parents of children aged ≤18 years recruited in the emergency department of a level 1 paediatric trauma centre. The intervention group received an educational tool, a spiral-bound, laminated booklet that resembled a CO detector containing theory-based safety messages based on the precaution adoption process model, a plug-in CO detector and 9 V battery. The control group received a one page flyer on CO poisoning prevention. Results Although the difference was not statistically significant, mean CO knowledge score increased at a greater rate for the intervention group than the control group. Intervention group parents were more likely to exhibit ‘safe’ CO detector use than control group parents at the 2-week follow-up (RR: 2.75; 95% CI 2.06 to 3.69) and 6-month follow-up (RR: 2.78; 95% CI 2.06 to 3.76), after adjusting for self-reported CO detector use behaviour at enrolment and annual per capita income. Conclusions An emergency department-delivered intervention containing a theory-based educational tool paired with a CO detector can be an effective method for increasing knowledge about CO poisoning, for prevention and for appropriate use of a CO detector. Trial registration number NCT00959478. PMID:28007971

Paediatric emergency department-based carbon monoxide detector intervention: a randomised trial.

PubMed

McKenzie, Lara B; Roberts, Kristin J; Kaercher, Roxanne M; Collins, Christy L; Comstock, R Dawn; Fernandez, Soledad; Abdel-Rasoul, Mahmoud; Casavant, Marcel J; Mihalov, Leslie

2017-10-01

Although non-fire-related carbon monoxide (CO) poisoning is almost entirely preventable, over 400 people die and 20 000 people are injured each year in the USA from unintentional CO poisoning. Thus, there is a critical need for evidence-based interventions for preventing CO poisoning and increasing the proper use and installation of CO detectors. A randomised, controlled trial (Project CODE, a Carbon Monoxide Detector Education intervention) with 2-week and 6-month follow-up home observations was conducted in 299 parents of children aged ≤18 years recruited in the emergency department of a level 1 paediatric trauma centre. The intervention group received an educational tool, a spiral-bound, laminated booklet that resembled a CO detector containing theory-based safety messages based on the precaution adoption process model, a plug-in CO detector and 9 V battery. The control group received a one page flyer on CO poisoning prevention. Although the difference was not statistically significant, mean CO knowledge score increased at a greater rate for the intervention group than the control group. Intervention group parents were more likely to exhibit 'safe' CO detector use than control group parents at the 2-week follow-up (RR: 2.75; 95% CI 2.06 to 3.69) and 6-month follow-up (RR: 2.78; 95% CI 2.06 to 3.76), after adjusting for self-reported CO detector use behaviour at enrolment and annual per capita income. An emergency department-delivered intervention containing a theory-based educational tool paired with a CO detector can be an effective method for increasing knowledge about CO poisoning, for prevention and for appropriate use of a CO detector. NCT00959478. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Development of 4-Sides Buttable CdTe-ASIC Hybrid Module for X-ray Flat Panel Detector

NASA Astrophysics Data System (ADS)

Tamaki, Mitsuru; Mito, Yoshio; Shuto, Yasuhiro; Kiyuna, Tatsuya; Yamamoto, Masaya; Sagae, Kenichi; Kina, Tooru; Koizumi, Tatsuhiro; Ohno, Ryoichi

2009-08-01

A 4-sides buttable CdTe-ASIC hybrid module suitable for use in an X-ray flat panel detector (FPD) has been developed by applying through silicon via (TSV) technology to the readout ASIC. The ASIC has 128 times 256 channels of charge integration type readout circuitry and an area of 12.9 mm times 25.7 mm. The CdTe sensor of 1 mm thickness, having the same area and pixel of 100 mum pitch, was fabricated from the Cl-doped CdTe single crystal grown by traveling heater method (THM). Then the CdTe pixel sensor was hybridized with the ASIC using the bump-bonding technology. The basic performance of this 4-sides buttable module was evaluated by taking X-ray images, and it was compared with that of a commercially available indirect type CsI(Tl) FPD. A prototype CdTe FPD was made by assembling 9 pieces of the 4-sides buttable modules into 3 times 3 arrays in which the neighboring modules were mounted on the interface board. The FPD covers an active area of 77 mm times 39 mm. The results showed the great potential of this 4-sides buttable module for the new real time X-ray FPD with high spatial resolution.

6. COMPRESSOR CONTROL PANELS: AT LEFT, 6,000 P.S.I. PANEL, CIRCA ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. COMPRESSOR CONTROL PANELS: AT LEFT, 6,000 P.S.I. PANEL, CIRCA 1957; AT RIGHT, FACING CAMERA, 10,000 P.S.I. PANEL. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Helium Compression Plant, Test Area 1-115, intersection of Altair & Saturn Boulevards, Boron, Kern County, CA

Characterization of a Polymer-Based MEMS Pyroelectric Infrared Detector

DTIC Science & Technology

2007-03-01

The value, K, in Equation (8) is generic to all thermal detectors. This value, depending on the type of thermal detector, varies due to the ... the current generated due to a ramp in temperature. The main rationale for this biasing is to align the polar axis perpendicular to the face of ...PVA_CB-based imaging system . Due to the

Software-Based Real-Time Acquisition and Processing of PET Detector Raw Data.

PubMed

Goldschmidt, Benjamin; Schug, David; Lerche, Christoph W; Salomon, André; Gebhardt, Pierre; Weissler, Bjoern; Wehner, Jakob; Dueppenbecker, Peter M; Kiessling, Fabian; Schulz, Volkmar

2016-02-01

In modern positron emission tomography (PET) readout architectures, the position and energy estimation of scintillation events (singles) and the detection of coincident events (coincidences) are typically carried out on highly integrated, programmable printed circuit boards. The implementation of advanced singles and coincidence processing (SCP) algorithms for these architectures is often limited by the strict constraints of hardware-based data processing. In this paper, we present a software-based data acquisition and processing architecture (DAPA) that offers a high degree of flexibility for advanced SCP algorithms through relaxed real-time constraints and an easily extendible data processing framework. The DAPA is designed to acquire detector raw data from independent (but synchronized) detector modules and process the data for singles and coincidences in real-time using a center-of-gravity (COG)-based, a least-squares (LS)-based, or a maximum-likelihood (ML)-based crystal position and energy estimation approach (CPEEA). To test the DAPA, we adapted it to a preclinical PET detector that outputs detector raw data from 60 independent digital silicon photomultiplier (dSiPM)-based detector stacks and evaluated it with a [(18)F]-fluorodeoxyglucose-filled hot-rod phantom. The DAPA is highly reliable with less than 0.1% of all detector raw data lost or corrupted. For high validation thresholds (37.1 ± 12.8 photons per pixel) of the dSiPM detector tiles, the DAPA is real time capable up to 55 MBq for the COG-based CPEEA, up to 31 MBq for the LS-based CPEEA, and up to 28 MBq for the ML-based CPEEA. Compared to the COG-based CPEEA, the rods in the image reconstruction of the hot-rod phantom are only slightly better separable and less blurred for the LS- and ML-based CPEEA. While the coincidence time resolution (∼ 500 ps) and energy resolution (∼12.3%) are comparable for all three CPEEA, the system sensitivity is up to 2.5 × higher for the LS- and ML-based CPEEA.

Use of Internet panels to conduct surveys.

PubMed

Hays, Ron D; Liu, Honghu; Kapteyn, Arie

2015-09-01

The use of Internet panels to collect survey data is increasing because it is cost-effective, enables access to large and diverse samples quickly, takes less time than traditional methods to obtain data for analysis, and the standardization of the data collection process makes studies easy to replicate. A variety of probability-based panels have been created, including Telepanel/CentERpanel, Knowledge Networks (now GFK KnowledgePanel), the American Life Panel, the Longitudinal Internet Studies for the Social Sciences panel, and the Understanding America Study panel. Despite the advantage of having a known denominator (sampling frame), the probability-based Internet panels often have low recruitment participation rates, and some have argued that there is little practical difference between opting out of a probability sample and opting into a nonprobability (convenience) Internet panel. This article provides an overview of both probability-based and convenience panels, discussing potential benefits and cautions for each method, and summarizing the approaches used to weight panel respondents in order to better represent the underlying population. Challenges of using Internet panel data are discussed, including false answers, careless responses, giving the same answer repeatedly, getting multiple surveys from the same respondent, and panelists being members of multiple panels. More is to be learned about Internet panels generally and about Web-based data collection, as well as how to evaluate data collected using mobile devices and social-media platforms.

Application of GEM-based detectors in full-field XRF imaging

NASA Astrophysics Data System (ADS)

Dąbrowski, W.; Fiutowski, T.; Frączek, P.; Koperny, S.; Lankosz, M.; Mendys, A.; Mindur, B.; Świentek, K.; Wiącek, P.; Wróbel, P. M.

2016-12-01

X-ray fluorescence spectroscopy (XRF) is a commonly used technique for non-destructive elemental analysis of cultural heritage objects. It can be applied to investigations of provenance of historical objects as well as to studies of art techniques. While the XRF analysis can be easily performed locally using standard available equipment there is a growing interest in imaging of spatial distribution of specific elements. Spatial imaging of elemental distrbutions is usually realised by scanning an object with a narrow focused X-ray excitation beam and measuring characteristic fluorescence radiation using a high energy resolution detector, usually a silicon drift detector. Such a technique, called macro-XRF imaging, is suitable for investigation of flat surfaces but it is time consuming because the spatial resolution is basically determined by the spot size of the beam. Another approach is the full-field XRF, which is based on simultaneous irradiation and imaging of large area of an object. The image of the investigated area is projected by a pinhole camera on a position-sensitive and energy dispersive detector. The infinite depth of field of the pinhole camera allows one, in principle, investigation of non-flat surfaces. One of possible detectors to be employed in full-field XRF imaging is a GEM based detector with 2-dimensional readout. In the paper we report on development of an imaging system equipped with a standard 3-stage GEM detector of 10 × 10 cm2 equipped with readout electronics based on dedicated full-custom ASICs and DAQ system. With a demonstrator system we have obtained 2-D spatial resolution of the order of 100 μm and energy resolution at a level of 20% FWHM for 5.9 keV . Limitations of such a detector due to copper fluorescence radiation excited in the copper-clad drift electrode and GEM foils is discussed and performance of the detector using chromium-clad electrodes is reported.

NEW LENSLET BASED IFS WITH HIGH DETECTOR PIXEL EFFICIENCY

NASA Astrophysics Data System (ADS)

Gong, Qian

2018-01-01

Three IFS types currently used for optical design are: lenslet array, imager slicer, and lenslet array and fiber combined. Lenslet array based Integral Field Spectroscopy (IFS) is very popular for many astrophysics applications due to its compactness, simplicity, as well as cost and mass savings. The disadvantage of lenslet based IFS is its low detector pixel efficiency. Enough spacing is needed between adjacent spectral traces in cross dispersion direction to avoid wavelength cross-talk, because the same wavelength is not aligned to the same column on detector. Such as on a recent exoplanet coronagraph instrument study to support the coming astrophysics decadal survey (LUVOIR), to cover a 45 λ/D Field of View (FOV) with a spectral resolving power of 200 at shortest wavelength, a 4k x 4k detector array is needed. This large format EMCCD pushes the detector into technology development area with a low TRL. Besides the future mission, it will help WFIRST coronagraph IFS by packing all spectra into a smaller area on detector, which will reduce the chance for electrons to be trapped in pixels, and slow the detector degradation during the mission.The innovation we propose here is to increase the detector packing efficiency by grouping a number of lenslets together to form many mini slits. In other words, a number of spots (Point Spread Function at lenslet focus) are aligned into a line to resemble a mini slit. Therefore, wavelength cross-talk is no longer a concern anymore. This combines the advantage of lenslet array and imager slicer together. The isolation rows between spectral traces in cross dispersion direction can be reduced or removed. So the packing efficiency is greatly increased. Furthermore, the today’s microlithography and etching technique is capable of making such a lenslet array, which will relax the detector demand significantly. It will finally contribute to the habitable exoplanets study to analyzing their spectra from direct images. Detailed theory

High-performance dual-energy imaging with a flat-panel detector: imaging physics from blackboard to benchtop to bedside

NASA Astrophysics Data System (ADS)

Siewerdsen, J. H.; Shkumat, N. A.; Dhanantwari, A. C.; Williams, D. B.; Richard, S.; Daly, M. J.; Paul, N. S.; Moseley, D. J.; Jaffray, D. A.; Yorkston, J.; Van Metter, R.

2006-03-01

The application of high-performance flat-panel detectors (FPDs) to dual-energy (DE) imaging offers the potential for dramatically improved detection and characterization of subtle lesions through reduction of "anatomical noise," with applications ranging from thoracic imaging to image-guided interventions. In this work, we investigate DE imaging performance from first principles of image science to preclinical implementation, including: 1.) generalized task-based formulation of NEQ and detectability as a guide to system optimization; 2.) measurements of imaging performance on a DE imaging benchtop; and 3.) a preclinical system developed in our laboratory for cardiac-gated DE chest imaging in a research cohort of 160 patients. Theoretical and benchtop studies directly guide clinical implementation, including the advantages of double-shot versus single-shot DE imaging, the value of differential added filtration between low- and high-kVp projections, and optimal selection of kVp pairs, filtration, and dose allocation. Evaluation of task-based NEQ indicates that the detectability of subtle lung nodules in double-shot DE imaging can exceed that of single-shot DE imaging by a factor of 4 or greater. Filter materials are investigated that not only harden the high-kVp beam (e.g., Cu or Ag) but also soften the low-kVp beam (e.g., Ce or Gd), leading to significantly increased contrast in DE images. A preclinical imaging system suitable for human studies has been constructed based upon insights gained from these theoretical and experimental studies. An important component of the system is a simple and robust means of cardiac-gated DE image acquisition, implemented here using a fingertip pulse oximeter. Timing schemes that provide cardiac-gated image acquisition on the same or successive heartbeats is described. Preclinical DE images to be acquired under research protocol will afford valuable testing of optimal deployment, facilitate the development of DE CAD, and support

Effects of loop detector installation on the Portland cement concrete pavement lifespan : case study on I-5.

DOT National Transportation Integrated Search

2010-08-01

The installation of loop detectors in portland cement concrete pavement (PCCP) may shorten affected panel life, thus prematurely worsening the condition of the overall pavement. This study focuses on the performance of those loop embedded panels (LEP...

Highly stretchable, transparent ionic touch panel

NASA Astrophysics Data System (ADS)

Kim, Chong-Chan; Lee, Hyun-Hee; Oh, Kyu Hwan; Sun, Jeong-Yun

2016-08-01

Because human-computer interactions are increasingly important, touch panels may require stretchability and biocompatibility in order to allow integration with the human body. However, most touch panels have been developed based on stiff and brittle electrodes. We demonstrate an ionic touch panel based on a polyacrylamide hydrogel containing lithium chloride salts. The panel is soft and stretchable, so it can sustain a large deformation. The panel can freely transmit light information because the hydrogel is transparent, with 98% transmittance for visible light. A surface-capacitive touch system was adopted to sense a touched position. The panel can be operated under more than 1000% areal strain without sacrificing its functionalities. Epidermal touch panel use on skin was demonstrated by writing words, playing a piano, and playing games.

Lightweight composites for modular panelized construction

NASA Astrophysics Data System (ADS)

Vaidya, Amol S.

Rapid advances in construction materials technology have enabled civil engineers to achieve impressive gains in the safety, economy, and functionality of structures built to serve the common needs of society. Modular building systems is a fast-growing modern, form of construction gaining recognition for its increased efficiency and ability to apply modern technology to the needs of the market place. In the modular construction technique, a single structural panel can perform a number of functions such as providing thermal insulation, vibration damping, and structural strength. These multifunctional panels can be prefabricated in a manufacturing facility and then transferred to the construction site. A system that uses prefabricated panels for construction is called a "panelized construction system". This study focuses on the development of pre-cast, lightweight, multifunctional sandwich composite panels to be used for panelized construction. Two thermoplastic composite panels are proposed in this study, namely Composite Structural Insulated Panels (CSIPs) for exterior walls, floors and roofs, and Open Core Sandwich composite for multifunctional interior walls of a structure. Special manufacturing techniques are developed for manufacturing these panels. The structural behavior of these panels is analyzed based on various building design codes. Detailed descriptions of the design, cost analysis, manufacturing, finite element modeling and structural testing of these proposed panels are included in this study in the of form five peer-reviewed journal articles. The structural testing of the proposed panels involved in this study included flexural testing, axial compression testing, and low and high velocity impact testing. Based on the current study, the proposed CSIP wall and floor panels were found satisfactory, based on building design codes ASCE-7-05 and ACI-318-05. Joining techniques are proposed in this study for connecting the precast panels on the construction

An LFMCW detector with new structure and FRFT based differential distance estimation method.

PubMed

Yue, Kai; Hao, Xinhong; Li, Ping

2016-01-01

This paper describes a linear frequency modulated continuous wave (LFMCW) detector which is designed for a collision avoidance radar. This detector can estimate distance between the detector and pedestrians or vehicles, thereby it will help to reduce the likelihood of traffic accidents. The detector consists of a transceiver and a signal processor. A novel structure based on the intermediate frequency signal (IFS) is designed for the transceiver which is different from the traditional LFMCW transceiver using the beat frequency signal (BFS) based structure. In the signal processor, a novel fractional Fourier transform (FRFT) based differential distance estimation (DDE) method is used to detect the distance. The new IFS based structure is beneficial for the FRFT based DDE method to reduce the computation complexity, because it does not need the scan of the optimal FRFT order. Low computation complexity ensures the feasibility of practical applications. Simulations are carried out and results demonstrate the efficiency of the detector designed in this paper.

Final Environmental Assessment: Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst New Jersey

DTIC Science & Technology

2012-03-01

FINAL ENVIRONMENTAL ASSESSMENT Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst, New Jersey MARCH 2012...Final Environmental Assessment : Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst New Jersey 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Purpose Finding of No Significant Impact (FONSI) Environmental Assessment (EA

Fast neutron sensitivity of neutron detectors based on Boron-10 converter layers

NASA Astrophysics Data System (ADS)

Mauri, G.; Messi, F.; Kanaki, K.; Hall-Wilton, R.; Karnickis, E.; Khaplanov, A.; Piscitelli, F.

2018-03-01

In the last few years many detector technologies for thermal neutron detection have been developed in order to face the shortage of 3He, which is now much less available and more expensive. Moreover the 3He-based detectors can not fulfil the requirements in performance, e.g. the spatial resolution and the counting rate capability needed for the new instruments. The Boron-10-based gaseous detectors have been proposed as a suitable choice. This and other alternative technologies are being developed at ESS. Higher intensities mean higher signals but higher background as well. The signal-to-background ratio is an important feature to study, in particular the γ-ray and the fast neutron contributions. This paper investigates, for the first time, the fast neutrons sensitivity of 10B-based thermal neutron detector. It presents the study of the detector response as a function of energy threshold and the underlying physical mechanisms. The latter are explained with the help of theoretical considerations and simulations.

Mounting clips for panel installation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cavieres, Andres; Al-Haddad, Tristan; Goodman, Joseph

2017-02-14

An exemplary mounting clip for removably attaching panels to a supporting structure comprises a base, spring locking clips, a lateral flange, a lever flange, and a spring bonding pad. The spring locking clips extend upwardly from the base. The lateral flange extends upwardly from a first side of the base. The lateral flange comprises a slot having an opening configured to receive at least a portion of one of the one or more panels. The lever flange extends outwardly from the lateral flange. The spring bonding flange extends downwardly from the lever flange. At least a portion of the firstmore » spring bonding flange comprises a serrated edge for gouging at least a portion of the one or more panels when the one or more panels are attached to the mounting clip to electrically and mechanically couple the one or more panels to the mounting clip.« less

DSSD detectors development PACT, a new space Compton telescope at the horizon 2025

NASA Astrophysics Data System (ADS)

Laurent, P.; Khalil, M.; Dolgorouki, Y.; Bertoli, W.; Oger, R.; Bréelle, E.

2015-07-01

PACT is a Pair and Compton telescope that aims to make a sensitive survey of the gamma-ray sky between 100 keV and 100 MeV . It will be devoted to the detection of radioactivity lines from present and past supernova explosions, the observation of thousands of new blazars, and the study of polarized radiations from gamma-ray bursts, pulsars and accreting black holes. It will reach a sensitivity of one to two orders of magnitude lower than COMPTEL/CGRO (e.g. about 50 times lower for the broad-band, survey sensitivity at 1 MeV after 5 years). The PACT telescope is based upon three main components: a silicon-based gamma-ray tracker, a crystal-based calorimeter (e.g. CeBr3), and an anticoincidence detector made of plastic scintillator panels. Prototypes of the Silicon detector planes have been optimized and are currently tested in the APC laboratory.

Compact ion chamber based neutron detector

DOEpatents

Derzon, Mark S.; Galambos, Paul C.; Renzi, Ronald F.

2015-10-27

A directional neutron detector has an ion chamber formed in a dielectric material; a signal electrode and a ground electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; readout circuitry which is electrically coupled to the signal and ground electrodes; and a signal processor electrically coupled to the readout circuitry. The ion chamber has a pair of substantially planar electrode surfaces. The chamber pressure of the neutron absorbing material is selected such that the reaction particle ion trail length for neutrons absorbed by the neutron absorbing material is equal to or less than the distance between the electrode surfaces. The signal processor is adapted to determine a path angle for each absorbed neutron based on the rise time of the corresponding pulse in a time-varying detector signal.

Computational steering of GEM based detector simulations

NASA Astrophysics Data System (ADS)

Sheharyar, Ali; Bouhali, Othmane

2017-10-01

Gas based detector R&D relies heavily on full simulation of detectors and their optimization before final prototypes can be built and tested. These simulations in particular those with complex scenarios such as those involving high detector voltages or gas with larger gains are computationally intensive may take several days or weeks to complete. These long-running simulations usually run on the high-performance computers in batch mode. If the results lead to unexpected behavior, then the simulation might be rerun with different parameters. However, the simulations (or jobs) may have to wait in a queue until they get a chance to run again because the supercomputer is a shared resource that maintains a queue of other user programs as well and executes them as time and priorities permit. It may result in inefficient resource utilization and increase in the turnaround time for the scientific experiment. To overcome this issue, the monitoring of the behavior of a simulation, while it is running (or live), is essential. In this work, we employ the computational steering technique by coupling the detector simulations with a visualization package named VisIt to enable the exploration of the live data as it is produced by the simulation.

A novel radiation detector for removing scattered radiation in chest radiography: Monte Carlo simulation-based performance evaluation

NASA Astrophysics Data System (ADS)

Roh, Y. H.; Yoon, Y.; Kim, K.; Kim, J.; Kim, J.; Morishita, J.

2016-10-01

Scattered radiation is the main reason for the degradation of image quality and the increased patient exposure dose in diagnostic radiology. In an effort to reduce scattered radiation, a novel structure of an indirect flat panel detector has been proposed. In this study, a performance evaluation of the novel system in terms of image contrast as well as an estimation of the number of photons incident on the detector and the grid exposure factor were conducted using Monte Carlo simulations. The image contrast of the proposed system was superior to that of the no-grid system but slightly inferior to that of the parallel-grid system. The number of photons incident on the detector and the grid exposure factor of the novel system were higher than those of the parallel-grid system but lower than those of the no-grid system. The proposed system exhibited the potential for reduced exposure dose without image quality degradation; additionally, can be further improved by a structural optimization considering the manufacturer's specifications of its lead contents.

High dynamic range CMOS-based mammography detector for FFDM and DBT

NASA Astrophysics Data System (ADS)

Peters, Inge M.; Smit, Chiel; Miller, James J.; Lomako, Andrey

2016-03-01

Digital Breast Tomosynthesis (DBT) requires excellent image quality in a dynamic mode at very low dose levels while Full Field Digital Mammography (FFDM) is a static imaging modality that requires high saturation dose levels. These opposing requirements can only be met by a dynamic detector with a high dynamic range. This paper will discuss a wafer-scale CMOS-based mammography detector with 49.5 μm pixels and a CsI scintillator. Excellent image quality is obtained for FFDM as well as DBT applications, comparing favorably with a-Se detectors that dominate the X-ray mammography market today. The typical dynamic range of a mammography detector is not high enough to accommodate both the low noise and the high saturation dose requirements for DBT and FFDM applications, respectively. An approach based on gain switching does not provide the signal-to-noise benefits in the low-dose DBT conditions. The solution to this is to add frame summing functionality to the detector. In one X-ray pulse several image frames will be acquired and summed. The requirements to implement this into a detector are low noise levels, high frame rates and low lag performance, all of which are unique characteristics of CMOS detectors. Results are presented to prove that excellent image quality is achieved, using a single detector for both DBT as well as FFDM dose conditions. This method of frame summing gave the opportunity to optimize the detector noise and saturation level for DBT applications, to achieve high DQE level at low dose, without compromising the FFDM performance.

A mobility based vibroacoustic energy transmission simulation into an enclosure through a double-wall panel.

PubMed

Sahu, Atanu; Bhattacharya, Partha; Niyogi, Arup Guha; Rose, Michael

2017-06-01

Double-wall panels are known for their superior sound insulation properties over single wall panels as a sound barrier. The sound transmission phenomenon through a double-wall structure is a complex process involving vibroacoustic interaction between structural panels, the air-cushion in between, and the secondary acoustic domain. It is in this context a versatile and a fully coupled technique based on the finite-element-boundary element model is developed that enables estimation of sound transfer through a double-wall panel into an adjacent enclosure while satisfying the displacement compatibility across the interface. The contribution of individual components in the transmitted energy is identified through numerical simulations.

A first comparison of the responses of a 4He-based fast-neutron detector and a NE-213 liquid-scintillator reference detector

NASA Astrophysics Data System (ADS)

Jebali, R.; Scherzinger, J.; Annand, J. R. M.; Chandra, R.; Davatz, G.; Fissum, K. G.; Friederich, H.; Gendotti, U.; Hall-Wilton, R.; Håkansson, E.; Kanaki, K.; Lundin, M.; Murer, D.; Nilsson, B.; Rosborg, A.; Svensson, H.

2015-09-01

A first comparison has been made between the pulse-shape discrimination characteristics of a novel 4He-based pressurized scintillation detector and a NE-213 liquid-scintillator reference detector using an Am/Be mixed-field neutron and gamma-ray source and a high-resolution scintillation-pulse digitizer. In particular, the capabilities of the two fast neutron detectors to discriminate between neutrons and gamma-rays were investigated. The NE-213 liquid-scintillator reference cell produced a wide range of scintillation-light yields in response to the gamma-ray field of the source. In stark contrast, due to the size and pressure of the 4He gas volume, the 4He-based detector registered a maximum scintillation-light yield of 750keVee to the same gamma-ray field. Pulse-shape discrimination for particles with scintillation-light yields of more than 750keVee was excellent in the case of the 4He-based detector. Above 750keVee its signal was unambiguously neutron, enabling particle identification based entirely upon the amount of scintillation light produced.

Solar-diffuser panel and ratioing radiometer approach to satellite sensor on-board calibration

NASA Technical Reports Server (NTRS)

Slater, Philip N.; Palmer, James M.

1991-01-01

The use of a solar-diffuser panel is a desirable approach to the on-board absolute radiometric calibration of satellite multispectral sensors used for earth observation in the solar reflective spectral range. It provides a full aperture, full field, end-to-end calibration near the top of the sensor's dynamic range and across its entire spectral response range. A serious drawback is that the panel's reflectance, and the response of any simple detector used to monitor its reflectance may change with time. This paper briefly reviews some preflight and on-board methods for absolute calibration and introduces the ratioing-radiometer concept in which the radiance of the panel is ratioed with respect to the solar irradiance at the time the multispectral sensor is viewing the panel in its calibration mode.

Debris Detector Verification by Hvi-Tests

NASA Astrophysics Data System (ADS)

Bauer, Waldemar; Drolshagen, Gerhard; Vörsmann, Peter; Romberg, Oliver; Putzar, Robin

Information regarding Space Debris (SD) or Micrometeoroids (MM) impacting on spacecraft (S/C) or payloads (P/L) can be obtained by using environmental models e.g. MASTER (ESA) or ORDEM (NASA). The validation of such models is performed by comparison of simulated results with measured or orbital observed data. The latter is utilised for large particles and can be obtained from ground based or space based radars or telescopes. Data regarding very small but abundant particles can also be gained by analysis of retrieved hardware (e.g. Hubble Space Telescope, Space Shuttle Windows), which are brought from orbit back to Earth. Furthermore, in-situ impact detectors are an essential source for information on small size meteoroids and space debris. These kind of detectors are placed in orbit and collect impact data regarding SD and MM, sending data near real time via telemetry. Compared to the impact data which is gained by analysis of retrieved surfaces, the detected data comprise additional information regarding exact impact time and, depending on the type of detector, on the orbit and particles composition. Nevertheless, existing detectors have limitations. Since the detection area is small, statistically meaningful number of impacts are obtained for very small particles only. Measurements of particles in the size range of hundreds of microns to mm which are potentially damaging to S/C require larger sensor areas. To make use of the advantages of in-situ impact detectors and to increase the amount of impact data an innovative impact detector concept is currently under development at DLR in Bremen. Different to all previous impact detectors the Solar Generator based Impact Detector (SOLID) is not an add-on component on the S/C. SOLID makes use of existing subsystems of the S/C and adopts them for impact detection purposes. Since the number of impacts on a target in space depends linearly on the exposed area, the S/C solar panels offer a unique opportunity to use them for

Muon detector for the COSINE-100 experiment

NASA Astrophysics Data System (ADS)

Prihtiadi, H.; Adhikari, G.; Adhikari, P.; Barbosa de Souza, E.; Carlin, N.; Choi, S.; Choi, W. Q.; Djamal, M.; Ezeribe, A. C.; Ha, C.; Hahn, I. S.; Hubbard, A. J. F.; Jeon, E. J.; Jo, J. H.; Joo, H. W.; Kang, W.; Kang, W. G.; Kauer, M.; Kim, B. H.; Kim, H.; Kim, H. J.; Kim, K. W.; Kim, N. Y.; Kim, S. K.; Kim, Y. D.; Kim, Y. H.; Kudryavtsev, V. A.; Lee, H. S.; Lee, J.; Lee, J. Y.; Lee, M. H.; Leonard, D. S.; Lim, K. E.; Lynch, W. A.; Maruyama, R. H.; Mouton, F.; Olsen, S. L.; Park, H. K.; Park, H. S.; Park, J. S.; Park, K. S.; Pettus, W.; Pierpoint, Z. P.; Ra, S.; Rogers, F. R.; Rott, C.; Scarff, A.; Spooner, N. J. C.; Thompson, W. G.; Yang, L.; Yong, S. H.

2018-02-01

The COSINE-100 dark matter search experiment has started taking physics data with the goal of performing an independent measurement of the annual modulation signal observed by DAMA/LIBRA. A muon detector was constructed by using plastic scintillator panels in the outermost layer of the shield surrounding the COSINE-100 detector. It detects cosmic ray muons in order to understand the impact of the muon annual modulation on dark matter analysis. Assembly and initial performance tests of each module have been performed at a ground laboratory. The installation of the detector in the Yangyang Underground Laboratory (Y2L) was completed in the summer of 2016. Using three months of data, the muon underground flux was measured to be 328 ± 1(stat.)± 10(syst.) muons/m2/day. In this report, the assembly of the muon detector and the results from the analysis are presented.

Beta ray spectroscopy based on a plastic scintillation detector/silicon surface barrier detector coincidence telescope

NASA Astrophysics Data System (ADS)

Horowitz, Y. S.; Hirning, C. R.; Yuen, P.; Aikens, M.

1994-01-01

Beta radiation is now recognized as a significant radiation safety problem and several international conferences have recently been devoted to the problems of mixed field beta/photon dosimetry. Conventional dosimetry applies algorithms to thermoluminescence dosimetry (TLD) multi-element badges which attempt to extract dose information based on the comparison of TL signals from ``thick/thin'' and/or ``bare/filtered'' elements. These may be grossly innacurate due to inadequate or non-existant knowledge of the energy spectrum of both the beta radiation and the accompanying photon field, as well as other factors. In this paper, we discuss the operation of a beta-ray energy spectrometer based on a two element, E × dE detector telescope intended to support dose algorithms with beta spectral information. Beta energies are measured via a 5 cm diameter × 2 cm thick BC-404 plastic scintillator preceded by a single, 100 μm thick, totally depleted, silicon dE detector. Photon events in the E detector are rejected by requiring a coincidence between the E and dE detectors. Photon rejection ratios vary from 225:1 at 1.25 MeV (60Co) to 360:1 at 0.36 MeV (133Ba). The spectrometer is capable of measuring electron energies from a lower energy coincidence threshold of approximately 125 keV to an upper limit of 3.5 MeV. This energy range spans the great majority of beta-emitting radionuclides in nuclear facilities.

Long-distance entanglement-based quantum key distribution experiment using practical detectors.

PubMed

Takesue, Hiroki; Harada, Ken-Ichi; Tamaki, Kiyoshi; Fukuda, Hiroshi; Tsuchizawa, Tai; Watanabe, Toshifumi; Yamada, Koji; Itabashi, Sei-Ichi

2010-08-02

We report an entanglement-based quantum key distribution experiment that we performed over 100 km of optical fiber using a practical source and detectors. We used a silicon-based photon-pair source that generated high-purity time-bin entangled photons, and high-speed single photon detectors based on InGaAs/InP avalanche photodiodes with the sinusoidal gating technique. To calculate the secure key rate, we employed a security proof that validated the use of practical detectors. As a result, we confirmed the successful generation of sifted keys over 100 km of optical fiber with a key rate of 4.8 bit/s and an error rate of 9.1%, with which we can distill secure keys with a key rate of 0.15 bit/s.

Development of patient collation system by kinetic analysis for chest dynamic radiogram with flat panel detector

NASA Astrophysics Data System (ADS)

Tsuchiya, Yuichiro; Kodera, Yoshie

2006-03-01

In the picture archiving and communication system (PACS) environment, it is important that all images be stored in the correct location. However, if information such as the patient's name or identification number has been entered incorrectly, it is difficult to notice the error. The present study was performed to develop a system of patient collation automatically for dynamic radiogram examination by a kinetic analysis, and to evaluate the performance of the system. Dynamic chest radiographs during respiration were obtained by using a modified flat panel detector system. Our computer algorithm developed in this study was consisted of two main procedures, kinetic map imaging processing, and collation processing. Kinetic map processing is a new algorithm to visualize a movement for dynamic radiography; direction classification of optical flows and intensity-density transformation technique was performed. Collation processing consisted of analysis with an artificial neural network (ANN) and discrimination for Mahalanobis' generalized distance, those procedures were performed to evaluate a similarity of combination for the same person. Finally, we investigated the performance of our system using eight healthy volunteers' radiographs. The performance was shown as a sensitivity and specificity. The sensitivity and specificity for our system were shown 100% and 100%, respectively. This result indicated that our system has excellent performance for recognition of a patient. Our system will be useful in PACS management for dynamic chest radiography.

Instrumentation for Kinetic-Inductance-Detector-Based Submillimeter Radio Astronomy

NASA Astrophysics Data System (ADS)

Duan, Ran

A substantial amount of important scientific information is contained within astronomical data at the submillimeter and far-infrared (FIR) wavelengths, including information regarding dusty galaxies, galaxy clusters, and star-forming regions; however, these wavelengths are among the least-explored fields in astronomy because of the technological difficulties involved in such research. Over the past 20 years, considerable efforts have been devoted to developing submillimeter- and millimeter-wavelength astronomical instruments and telescopes. The number of detectors is an important property of such instruments and is the subject of the current study. Future telescopes will require as many as hundreds of thousands of detectors to meet the necessary requirements in terms of the field of view, scan speed, and resolution. A large pixel count is one benefit of the development of multiplexable detectors that use kinetic inductance detector (KID) technology. This dissertation presents the development of a KID-based instrument including a portion of the millimeter-wave bandpass filters and all aspects of the readout electronics, which together enabled one of the largest detector counts achieved to date in submillimeter-/millimeter-wavelength imaging arrays: a total of 2304 detectors. The work presented in this dissertation has been implemented in the MUltiwavelength Submillimeter Inductance Camera (MUSIC), a new instrument for the Caltech Submillimeter Observatory (CSO).

Study of a GaAs:Cr-based Timepix detector using synchrotron facility

NASA Astrophysics Data System (ADS)

Smolyanskiy, P.; Kozhevnikov, D.; Bakina, O.; Chelkov, G.; Dedovich, D.; Kuper, K.; Leyva Fabelo, A.; Zhemchugov, A.

2017-11-01

High resistivity gallium arsenide compensated by chromium fabricated by Tomsk State University has demonstrated a good suitability as a sensor material for hybrid pixel detectors used in X-ray imaging systems with photon energies up to 60 keV. The material is available with a thickness up to 1 mm and due to its Z number a high absorption efficiency in this energy region is provided. However, the performance of thick GaAs:Cr-based detectors in spectroscopic applications is limited by readout electronics with relatively small pixels due to the charge sharing effect. In this paper, we present the experimental investigation of the charge sharing effect contribution in the GaAs:Cr-based Timepix detector. By means of scanning the detector with a pencil photon beam generated by the synchrotron facility, the geometrical mapping of pixel sensitivity is obtained, as well as the energy resolution of a single pixel. The experimental results are supported by numerical simulations. The observed limitation of the GaAs:Cr-based Timepix detector for the high flux X-ray imaging is discussed.

GaN-Based Detector Enabling Technology for Next Generation Ultraviolet Planetary Missions

NASA Technical Reports Server (NTRS)

Aslam, S.; Gronoff, G.; Hewagama, T.; Janz, S.; Kotecki, C.

2012-01-01

The ternary alloy AlN-GaN-InN system provides several distinct advantages for the development of UV detectors for future planetary missions. First, (InN), (GaN) and (AlN) have direct bandgaps 0.8, 3.4 and 6.2 eV, respectively, with corresponding wavelength cutoffs of 1550 nm, 365 nm and 200 nm. Since they are miscible with each other, these nitrides form complete series of indium gallium nitride (In(sub l-x)Ga(sub x)N) and aluminum gallium nitride (Al(sub l-x)Ga(sub x)N) alloys thus allowing the development of detectors with a wavelength cut-off anywhere in this range. For the 2S0-365 nm spectral wavelength range AlGaN detectors can be designed to give a 1000x solar radiation rejection at cut-off wavelength of 325 nm, than can be achieved with Si based detectors. For tailored wavelength cut-offs in the 365-4S0 nm range, InGaN based detectors can be fabricated, which still give 20-40x better solar radiation rejection than Si based detectors. This reduced need for blocking filters greatly increases the Detective Quantum efficiency (DQE) and simplifies the instrument's optical systems. Second, the wide direct bandgap reduces the thermally generated dark current to levels allowing many observations to be performed at room temperature. Third, compared to narrow bandgap materials, wide bandgap semiconductors are significantly more radiation tolerant. Finally, with the use of an (AI, In)GaN array, the overall system cost is reduced by eliminating stringent Si CCD cooling systems. Compared to silicon, GaN based detectors have superior QE based on a direct bandgap and longer absorption lengths in the UV.

Fast ADC based multichannel acquisition system for the GEM detector

NASA Astrophysics Data System (ADS)

Kasprowicz, G.; Czarski, T.; Chernyshova, M.; Dominik, W.; Jakubowska, K.; Karpinski, L.; Kierzkowski, K.; Pozniak, K.; Rzadkiewicz, J.; Scholz, M.; Zabolotny, W.

2012-05-01

A novel approach to the Gas Electron Multiplier1 (GEM) detector readout is presented. Unlike commonly used methods, based on discriminators, and analogue FIFOs,[ the method developed uses simultaneously sampling high speed ADCs and advanced FPGA-based processing logic to estimate the energy of every single photon. Such method is applied to every GEM strip signal. It is especially useful in case of crystal-based spectrometers for soft X-rays, where higher order reflections need to be identified and rejected. For the purpose of the detector readout, a novel conception of the measurement platform was developed.

Basic imaging properties of an indirect flat-panel detector system employing irradiation side sampling (ISS) technology for chest radiography: comparison with a computed radiographic system.

PubMed

Tanaka, Nobukazu; Yano, Yuki; Yabuuchi, Hidetake; Akasaka, Tsutomu; Sasaki, Masayuki; Ohki, Masafumi; Morishita, Junji

2013-01-01

The image quality and potential usefulness for patient skin-dose reduction of a newly developed flat-panel detector (FPD) system employing irradiation side sampling (ISS) were investigated and compared to a conventional computed radiography (CR) system. We used the X-ray beam quality of RQA 9 as noted in the standard evaluation method by the International Electrotechnical Commission 62220-1 to evaluate the image quality of the detector for chest radiography. The presampled modulation transfer function (MTF) of the ISS-FPD system was slightly higher than that of the CR system in the horizontal direction at more than 2.2 cycles/mm. However, the presampled MTF of the ISS-FPD system was slightly lower than that of the CR system in the vertical direction. The Wiener spectrum of the ISS-FPD system showed a 50-65 % lesser noise level than that of the CR system under the same exposure condition. The detective quantum efficiency of the ISS-FPD system was at least twice as great as that of the CR system. We conclude that the ISS-FPD system has the potential to reduce the patient skin dose compared to a conventional CR system for chest radiography.

A Wireless Sensor Network-Based Portable Vehicle Detector Evaluation System

PubMed Central

Yoo, Seong-eun

2013-01-01

In an upcoming smart transportation environment, performance evaluations of existing Vehicle Detection Systems are crucial to maintain their accuracy. The existing evaluation method for Vehicle Detection Systems is based on a wired Vehicle Detection System reference and a video recorder, which must be operated and analyzed by capable traffic experts. However, this conventional evaluation system has many disadvantages. It is inconvenient to deploy, the evaluation takes a long time, and it lacks scalability and objectivity. To improve the evaluation procedure, this paper proposes a Portable Vehicle Detector Evaluation System based on wireless sensor networks. We describe both the architecture and design of a Vehicle Detector Evaluation System and the implementation results, focusing on the wireless sensor networks and methods for traffic information measurement. With the help of wireless sensor networks and automated analysis, our Vehicle Detector Evaluation System can evaluate a Vehicle Detection System conveniently and objectively. The extensive evaluations of our Vehicle Detector Evaluation System show that it can measure the traffic information such as volume counts and speed with over 98% accuracy. PMID:23344388

A wireless sensor network-based portable vehicle detector evaluation system.

PubMed

Yoo, Seong-eun

2013-01-17

In an upcoming smart transportation environment, performance evaluations of existing Vehicle Detection Systems are crucial to maintain their accuracy. The existing evaluation method for Vehicle Detection Systems is based on a wired Vehicle Detection System reference and a video recorder, which must be operated and analyzed by capable traffic experts. However, this conventional evaluation system has many disadvantages. It is inconvenient to deploy, the evaluation takes a long time, and it lacks scalability and objectivity. To improve the evaluation procedure, this paper proposes a Portable Vehicle Detector Evaluation System based on wireless sensor networks. We describe both the architecture and design of a Vehicle Detector Evaluation System and the implementation results, focusing on the wireless sensor networks and methods for traffic information measurement. With the help of wireless sensor networks and automated analysis, our Vehicle Detector Evaluation System can evaluate a Vehicle Detection System conveniently and objectively. The extensive evaluations of our Vehicle Detector Evaluation System show that it can measure the traffic information such as volume counts and speed with over 98% accuracy.

TES-Based Light Detectors for the CRESST Direct Dark Matter Search

NASA Astrophysics Data System (ADS)

Rothe, J.; Angloher, G.; Bauer, P.; Bento, A.; Bucci, C.; Canonica, L.; D'Addabbo, A.; Defay, X.; Erb, A.; Feilitzsch, F. v.; Ferreiro Iachellini, N.; Gorla, P.; Gütlein, A.; Hauff, D.; Jochum, J.; Kiefer, M.; Kluck, H.; Kraus, H.; Lanfranchi, J.-C.; Langenkämper, A.; Loebell, J.; Mancuso, M.; Mondragon, E.; Münster, A.; Pagliarone, C.; Petricca, F.; Potzel, W.; Pröbst, F.; Puig, R.; Reindl, F.; Schäffner, K.; Schieck, J.; Schipperges, V.; Schönert, S.; Seidel, W.; Stahlberg, M.; Stodolsky, L.; Strandhagen, C.; Strauss, R.; Tanzke, A.; Trinh Thi, H. H.; Türkoğlu, C.; Ulrich, A.; Usherov, I.; Wawoczny, S.; Willers, M.; Wüstrich, M.

2018-05-01

The CRESST experiment uses cryogenic detectors based on transition-edge sensors to search for dark matter interactions. Each detector module consists of a scintillating CaWO_4 crystal and a silicon-on-sapphire (SOS) light detector which operate in coincidence (phonon-light technique). The 40-mm-diameter SOS disks (2 g mass) used in the data taking campaign of CRESST-II Phase 2 (2014-2016) reached absolute baseline resolutions of σ = 4-7 eV. This is the best performance reported for cryogenic light detectors of this size. Newly developed silicon beaker light detectors (4 cm height, 4 cm diameter, 6 g mass), which cover a large fraction of the target crystal surface, have achieved a baseline resolution of σ = 5.8 eV. First results of further improved light detectors developed for the ongoing low-threshold CRESST-III experiment are presented.

Selection bias of Internet panel surveys: a comparison with a paper-based survey and national governmental statistics in Japan.

PubMed

Tsuboi, Satoshi; Yoshida, Honami; Ae, Ryusuke; Kojo, Takao; Nakamura, Yosikazu; Kitamura, Kunio

2015-03-01

To investigate the selection bias of an Internet panel survey organized by a commercial company. A descriptive study was conducted. The authors compared the characteristics of the Internet panel survey with a national paper-based survey and with national governmental statistics in Japan. The participants in the Internet panel survey were composed of more women, were older, and resided in large cities. Regardless of age and sex, the prevalence of highly educated people in the Internet panel survey was higher than in the paper-based survey and the national statistics. In men, the prevalence of heavy drinkers among the 30- to 49-year-old population and of habitual smokers among the 20- to 49-year-old population in the Internet panel survey was lower than what was found in the national statistics. The estimated characteristics of commercial Internet panel surveys were quite different from the national statistical data. In a commercial Internet panel survey, selection bias should not be underestimated. © 2012 APJPH.

Long-distance transmission of light in a scintillator-based radiation detector

DOEpatents

Dowell, Jonathan L.; Talbott, Dale V.; Hehlen, Markus P.

2017-07-11

Scintillator-based radiation detectors capable of transmitting light indicating the presence of radiation for long distances are disclosed herein. A radiation detector can include a scintillator layer and a light-guide layer. The scintillator layer is configured to produce light upon receiving incident radiation. The light-guide layer is configured to receive light produced by the scintillator layer and either propagate the received light through the radiation detector or absorb the received light and emit light, through fluorescence, that is propagated through the radiation detector. A radiation detector can also include an outer layer partially surrounding the scintillator layer and light-guide layer. The index of refraction of the light-guide layer can be greater than the index of refraction of adjacent layers.

Geometric correction methods for Timepix based large area detectors

NASA Astrophysics Data System (ADS)

Zemlicka, J.; Dudak, J.; Karch, J.; Krejci, F.

2017-01-01

X-ray micro radiography with the hybrid pixel detectors provides versatile tool for the object inspection in various fields of science. It has proven itself especially suitable for the samples with low intrinsic attenuation contrast (e.g. soft tissue in biology, plastics in material sciences, thin paint layers in cultural heritage, etc.). The limited size of single Medipix type detector (1.96 cm2) was recently overcome by the construction of large area detectors WidePIX assembled of Timepix chips equipped with edgeless silicon sensors. The largest already built device consists of 100 chips and provides fully sensitive area of 14.3 × 14.3 cm2 without any physical gaps between sensors. The pixel resolution of this device is 2560 × 2560 pixels (6.5 Mpix). The unique modular detector layout requires special processing of acquired data to avoid occurring image distortions. It is necessary to use several geometric compensations after standard corrections methods typical for this type of pixel detectors (i.e. flat-field, beam hardening correction). The proposed geometric compensations cover both concept features and particular detector assembly misalignment of individual chip rows of large area detectors based on Timepix assemblies. The former deals with larger border pixels in individual edgeless sensors and their behaviour while the latter grapple with shifts, tilts and steps between detector rows. The real position of all pixels is defined in Cartesian coordinate system and together with non-binary reliability mask it is used for the final image interpolation. The results of geometric corrections for test wire phantoms and paleo botanic material are presented in this article.

Radiation imaging with optically read out GEM-based detectors

NASA Astrophysics Data System (ADS)

Brunbauer, F. M.; Lupberger, M.; Oliveri, E.; Resnati, F.; Ropelewski, L.; Streli, C.; Thuiner, P.; van Stenis, M.

2018-02-01

Modern imaging sensors allow for high granularity optical readout of radiation detectors such as MicroPattern Gaseous Detectors (MPGDs). Taking advantage of the high signal amplification factors achievable by MPGD technologies such as Gaseous Electron Multipliers (GEMs), highly sensitive detectors can be realised and employing gas mixtures with strong scintillation yield in the visible wavelength regime, optical readout of such detectors can provide high-resolution event representations. Applications from X-ray imaging to fluoroscopy and tomography profit from the good spatial resolution of optical readout and the possibility to obtain images without the need for extensive reconstruction. Sensitivity to low-energy X-rays and energy resolution permit energy resolved imaging and material distinction in X-ray fluorescence measurements. Additionally, the low material budget of gaseous detectors and the possibility to couple scintillation light to imaging sensors via fibres or mirrors makes optically read out GEMs an ideal candidate for beam monitoring detectors in high energy physics as well as radiotherapy. We present applications and achievements of optically read out GEM-based detectors including high spatial resolution imaging and X-ray fluorescence measurements as an alternative readout approach for MPGDs. A detector concept for low intensity applications such as X-ray crystallography, which maximises detection efficiency with a thick conversion region but mitigates parallax-induced broadening is presented and beam monitoring capabilities of optical readout are explored. Augmenting high resolution 2D projections of particle tracks obtained with optical readout with timing information from fast photon detectors or transparent anodes for charge readout, 3D reconstruction of particle trajectories can be performed and permits the realisation of optically read out time projection chambers. Combining readily available high performance imaging sensors with compatible

Data Base Management Systems Panel. Third workshop summary

NASA Technical Reports Server (NTRS)

Urena, J. L. (Editor)

1981-01-01

The discussions and results of a review by a panel of data base management system (DRMS) experts of various aspects of the use of DBMSs within NASA/Office of Space and Terrestrial Applications (OSTA) and related organizations are summarized. The topics discussed included the present status of the use of DBMS technology and of the various ongoing DBMS-related efforts within NASA. The report drafts of a study that seeks to determine the functional requirements for a generalized DBMS for the NASA/OSTA and related data bases are examined. Future problems and possibilities with the use of DBMS technology are also considered. A list of recommendations for NASA/OSTA data systems is included.

PREFACE: 2nd Workshop on Germanium Detectors and Technologies

NASA Astrophysics Data System (ADS)

Abt, I.; Majorovits, B.; Keller, C.; Mei, D.; Wang, G.; Wei, W.

2015-05-01

The 2nd workshop on Germanium (Ge) detectors and technology was held at the University of South Dakota on September 14-17th 2014, with more than 113 participants from 8 countries, 22 institutions, 15 national laboratories, and 8 companies. The participants represented the following big projects: (1) GERDA and Majorana for the search of neutrinoless double-beta decay (0νββ) (2) SuperCDMS, EDELWEISS, CDEX, and CoGeNT for search of dark matter; (3) TEXONO for sub-keV neutrino physics; (4) AGATA and GRETINA for gamma tracking; (5) AARM and others for low background radiation counting; (5) as well as PNNL and LBNL for applications of Ge detectors in homeland security. All participants have expressed a strong desire on having better understanding of Ge detector performance and advancing Ge technology for large-scale applications. The purpose of this workshop was to leverage the unique aspects of the underground laboratories in the world and the germanium (Ge) crystal growing infrastructure at the University of South Dakota (USD) by brining researchers from several institutions taking part in the Experimental Program to Stimulate Competitive Research (EPSCoR) together with key leaders from international laboratories and prestigious universities, working on the forefront of the intensity to advance underground physics focusing on the searches for dark matter, neutrinoless double-beta decay (0νββ), and neutrino properties. The goal of the workshop was to develop opportunities for EPSCoR institutions to play key roles in the planned world-class research experiments. The workshop was to integrate individual talents and existing research capabilities, from multiple disciplines and multiple institutions, to develop research collaborations, which includes EPSCor institutions from South Dakota, North Dakota, Alabama, Iowa, and South Carolina to support multi-ton scale experiments for future. The topic areas covered in the workshop were: 1) science related to Ge-based

A new kind of metal detector based on chaotic oscillator

NASA Astrophysics Data System (ADS)

Hu, Wenjing

2017-12-01

The sensitivity of a metal detector greatly depends on the identification ability to weak signals from the probe. In order to improve the sensitivity of metal detectors, this paper applies the Duffing chaotic oscillator to metal detectors based on its characteristic which is very sensitive to weak periodic signals. To make a suitable Duffing system for detectors, this paper computes two Lyapunov characteristics exponents of the Duffing oscillator, which help to obtain the threshold of the Duffing system in the critical state accurately and give quantitative criteria for chaos. Meanwhile, a corresponding simulation model of the chaotic oscillator is made by the Simulink tool box of Matlab. Simulation results shows that Duffing oscillator is very sensitive to sinusoidal signals in high frequency cases. And experimental results show that the measurable diameter of metal particles is about 1.5mm. It indicates that this new method can feasibly and effectively improve the metal detector sensitivity.

Operation of an InGrid based X-ray detector at the CAST experiment

NASA Astrophysics Data System (ADS)

Krieger, Christoph; Desch, Klaus; Kaminski, Jochen; Lupberger, Michael

2018-02-01

The CERN Axion Solar Telescope (CAST) is searching for axions and other particles which could be candidates for DarkMatter and even Dark Energy. These particles could be produced in the Sun and detected by a conversion into soft X-ray photons inside a strong magnetic field. In order to increase the sensitivity for physics beyond the Standard Model, detectors with a threshold below 1 keV as well as efficient background rejection methods are required to compensate for low energies and weak couplings resulting in very low detection rates. Those criteria are fulfilled by a detector utilizing the combination of a pixelized readout chip with an integrated Micromegas stage. These InGrid (Integrated Grid) devices can be build by photolithographic postprocessing techniques, resulting in a close to perfect match of grid and pixels facilitating the detection of single electrons on the chip surface. The high spatial resolution allows for energy determination by simple electron counting as well as for an event-shape based analysis as background rejection method. Tests at an X-ray generator revealed the energy threshold of an InGrid based X-ray detector to be well below the carbon Kα line at 277 eV. After the successful demonstration of the detectors key features, the detector was mounted at one of CAST's four detector stations behind an X-ray telescope in 2014. After several months of successful operation without any detector related interruptions, the InGrid based X-ray detector continues data taking at CAST in 2015. During operation at the experiment, background rates in the order of 10-5 keV-1 cm-2 s-1 have been achieved by application of a likelihood based method discriminating the non-photon background originating mostly from cosmic rays. For continued operation in 2016, an upgraded InGrid based detector is to be installed among other improvements including decoupling and sampling of the signal induced on the grid as well as a veto scintillator to further lower the

Kuipers sets up the EHS/TEPC Spectrometer and Detector Assembly in the SM

NASA Image and Video Library

2012-03-12

ISS030-E-177101 (12 March 2012) --- European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, sets up the Environmental Health System / Tissue Equivalent Proportional Counter (EHS/TEPC) spectrometer and detector assembly on panel 327 in the Zvezda Service Module of the International Space Station. The TEPC detector assembly is the primary radiation measurement tool on the space station.

Monte Carlo-based Reconstruction in Water Cherenkov Detectors using Chroma

NASA Astrophysics Data System (ADS)

Seibert, Stanley; Latorre, Anthony

2012-03-01

We demonstrate the feasibility of event reconstruction---including position, direction, energy and particle identification---in water Cherenkov detectors with a purely Monte Carlo-based method. Using a fast optical Monte Carlo package we have written, called Chroma, in combination with several variance reduction techniques, we can estimate the value of a likelihood function for an arbitrary event hypothesis. The likelihood can then be maximized over the parameter space of interest using a form of gradient descent designed for stochastic functions. Although slower than more traditional reconstruction algorithms, this completely Monte Carlo-based technique is universal and can be applied to a detector of any size or shape, which is a major advantage during the design phase of an experiment. As a specific example, we focus on reconstruction results from a simulation of the 200 kiloton water Cherenkov far detector option for LBNE.

Design of the flame detector based on pyroelectric infrared sensor

NASA Astrophysics Data System (ADS)

Liu, Yang; Yu, Benhua; Dong, Lei; Li, Kai

2017-10-01

As a fire detection device, flame detector has the advantages of short reaction time and long distance. Based on pyroelectric infrared sensor working principle, the passive pyroelectric infrared alarm system is designed, which is mainly used for safety of tunnel to detect whether fire occurred or not. Modelling and Simulation of the pyroelectric Detector Using Labview. An attempt was made to obtain a simple test platform of a pyroelectric detector which would make an excellent basis for the analysis of its dynamic behaviour. After many experiments, This system has sensitive response, high anti-interference ability and safe and reliable performance.

Reproducibility and calibration of MMC-based high-resolution gamma detectors

DOE PAGES

Bates, C. R.; Pies, C.; Kempf, S.; ...

2016-07-15

Here, we describe a prototype γ-ray detector based on a metallic magnetic calorimeter with an energy resolution of 46 eV at 60 keV and a reproducible response function that follows a simple second-order polynomial. The simple detector calibration allows adding high-resolution spectra from different pixels and different cool-downs without loss in energy resolution to determine γ-ray centroids with high accuracy. As an example of an application in nuclear safeguards enabled by such a γ-ray detector, we discuss the non-destructive assay of 242Pu in a mixed-isotope Pu sample.

Large Area Flat Panel Imaging Detectors for Astronomy and Night Time Sensing

NASA Astrophysics Data System (ADS)

Siegmund, O.; McPhate, J.; Frisch, H.; Elam, J.; Mane, A.; Wagner, R.; Varner, G.

2013-09-01

Sealed tube photo-sensing detectors for optical/IR detection have applications in astronomy, nighttime remote reconnaissance, and airborne/space situational awareness. The potential development of large area photon counting, imaging, timing detectors has significance for these applications and a number of other areas (High energy particle detection (RICH), biological single-molecule fluorescence lifetime imaging microscopy, neutron imaging, time of flight mass spectroscopy, diffraction imaging). We will present details of progress towards the development of a 20 cm sealed tube optical detector with nanoengineered microchannel plates for photon counting, imaging and sub-ns event time stamping. In the operational scheme of the photodetector incoming light passes through an entrance window and interacts with a semitransparent photocathode on the inside of the window. The photoelectrons emitted are accelerated across a proximity gap and are detected by an MCP pair. The pair of novel borosilicate substrate MCPs are functionalized by atomic layer deposition (ALD), and amplify the signal and the resulting electron cloud is detected by a conductive strip line anode for determination of the event positions and the time of arrival. The physical package is ~ 25 x 25 cm but only 1.5 cm thick. Development of such a device in a square 20 cm format presents challenges: hermetic sealing to a large entrance window, a 20 cm semitransparent photocathode with good efficiency and uniformity, 20 cm MCPs with reasonable cost and performance, robust construction to preserve high vacuum and withstand an atmosphere pressure differential. We will discuss the schemes developed to address these issues and present the results for the first test devices. The novel microchannel plates employing borosilicate micro-capillary arrays provide many performance characteristics typical of conventional MCPs, but have been made in sizes up to 20 cm, have low intrinsic background (0.08 events cm2 s-1) and

Characterization of LANDSAT Panels Using the NIST BRDF Scale from 1100 nm to 2500 nm

NASA Technical Reports Server (NTRS)

Markham, Brian; Tsai, Benjamin K.; Allen, David W.; Cooksey, Catherine; Yoon, Howard; Hanssen, Leonard; Zeng, Jinan; Fulton, Linda; Biggar, Stuart; Markham, Brian

2010-01-01

Many earth observing sensors depend on white diffuse reflectance standards to derive scales of radiance traceable to the St Despite the large number of Earth observing sensors that operate in the reflective solar region of the spectrum, there has been no direct method to provide NIST traceable BRDF measurements out to 2500 rim. Recent developments in detector technology have allowed the NIST reflectance measurement facility to expand the operating range to cover the 250 nm to 2500 nm range. The facility has been modified with and additional detector using a cooled extended range indium gallium arsenide (Extended InGaAs) detector. Measurements were made for two PTFE white diffuse reflectance standards over the 1100 nm to 2500 nm region at a 0' incident and 45' observation angle. These two panels will be used to support the OLI calibration activities. An independent means of verification was established using a NIST radiance transfer facility based on spectral irradiance, radiance standards and a diffuse reflectance plaque. An analysis on the results and associated uncertainties will be discussed.

Characterizing the response of a scintillator-based detector to single electrons.

PubMed

Sang, Xiahan; LeBeau, James M

2016-02-01

Here we report the response of a high angle annular dark field scintillator-based detector to single electrons. We demonstrate that care must be taken when determining the single electron intensity as significant discrepancies can occur when quantifying STEM images with different methods. To account for the detector response, we first image the detector using very low beam currents (∼8fA), and subsequently model the interval between consecutive single electrons events. We find that single electrons striking the detector present a wide distribution of intensities, which we show is not described by a simple function. Further, we present a method to accurately account for the electrons within the incident probe when conducting quantitative imaging. The role detector settings play on determining the single electron intensity is also explored. Finally, we extend our analysis to describe the response of the detector to multiple electron events within the dwell interval of each pixel. Copyright © 2015 Elsevier B.V. All rights reserved.

77 FR 15753 - Request for Nominations of Experts for a Science Advisory Board Panel To Review EPA's Web-Based...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-16

... Advisory Board Panel To Review EPA's Web-Based Report on the Environment AGENCY: Environmental Protection... nominations of technical experts to form an SAB panel to review the Agency's Web-based Report on the... procedural policies. EPA's Web-based Report on the Environment (ROE) has been developed to provide a...

Development of fire-resistant wood structural panels

NASA Technical Reports Server (NTRS)

Vaughan, T. W.; Etzold, R.

1977-01-01

Structural panels made with Xylok 210 resin as the binder had a burn-through resistance at least equal to the structural panels made with Kerimid 500. Therefore, because of its comparative ease of handling, Xylok 210 was selected as the resin binder to provide the baseline panel for the study of a means of improving the flame-spread resistance of the structural panels. The final resin-filler system consisted of Xylok 210 binder with the addition of ammonium oxalate and ammonium phosphate to the strands of the surface layers, using 24% of each salt based upon the air-dry weight of the strands. This system resulted in a panel with a flame-spread code of about 60, a Class 2 classification. A standard phenolic based structural panel had a flame-spread greater than 200 for laboratory prepared panels. The burn-through tests indicated an average burn-through time of 588 seconds for the specimens made with the final system. This compares to an average burn-through time of 287 seconds for the standard phenolic base structural specimen. One full-size panel was made with the final system.

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy

NASA Astrophysics Data System (ADS)

Kertzscher, Gustavo; Beddar, Sam

2016-11-01

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from  >5% to  <1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was  <3% as long as the source distance from the scintillator was  <7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by  >5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy

PubMed Central

Kertzscher, Gustavo; Beddar, Sam

2016-01-01

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from > 5% to < 1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was < 3% as long as the source distance from the scintillator was < 7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by > 5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy.

PubMed

Kertzscher, Gustavo; Beddar, Sam

2016-11-07

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from  >5% to  <1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was  <3% as long as the source distance from the scintillator was  <7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by  >5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the

Panel acoustic contribution analysis.

PubMed

Wu, Sean F; Natarajan, Logesh Kumar

2013-02-01

Formulations are derived to analyze the relative panel acoustic contributions of a vibrating structure. The essence of this analysis is to correlate the acoustic power flow from each panel to the radiated acoustic pressure at any field point. The acoustic power is obtained by integrating the normal component of the surface acoustic intensity, which is the product of the surface acoustic pressure and normal surface velocity reconstructed by using the Helmholtz equation least squares based nearfield acoustical holography, over each panel. The significance of this methodology is that it enables one to analyze and rank relative acoustic contributions of individual panels of a complex vibrating structure to acoustic radiation anywhere in the field based on a single set of the acoustic pressures measured in the near field. Moreover, this approach is valid for both interior and exterior regions. Examples of using this method to analyze and rank the relative acoustic contributions of a scaled vehicle cabin are demonstrated.

Fabrication of Gamma Detectors Based on Magnetic Ag:Er Microcalorimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedrich, Stephan; Boyd, Stephen; Cantor, Robin

2016-05-06

This report discusses the photolithographic fabrication of ultra-high resolution gamma-ray detectors based on magnetic microcalorimeters (MMCs). The MMC uses a novel Er-doped silver sensor (Ag:Er) that is expected to have higher sensitivity than the Er-doped gold (Au:Er) sensors currently in use. The MMC also integrates the first-stage SQUID preamplifier on the same chip as the MMC gamma detector to increase its signal-to-noise ratio. In addition, the MMC uses a passive Ta-Nb heat switch to replace one of the common long-term failure points in earlier detectors. This report discusses the fabrication process we have developed to implement the proposed improvements.

Fabrication of Gamma Detectors Based on Magnetic Ag:Er Microcalorimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedrich, Stephan; Boyd, Stephen; Cantor, Robin

2015-11-25

This report discusses the photolithographic fabrication of ultra-high resolution gamma-ray detectors based on magnetic microcalorimeters (MMCs). The MMC uses a novel Er-doped silver sensor (Ag:Er) that is expected to have higher sensitivity than the Er-doped gold (Au:Er) sensors currently in use. The MMC also integrates the first-stage SQUID preamplifier on the same chip as the MMC gamma detector to increase its signal-to-noise ratio. In addition, the MMC uses a passive Ta-Nb heat switch to replace one of the common long-term failure points in earlier detectors. This report discusses the fabrication process we have developed to implement the proposed improvements.

Solid-perforated panel layout optimization by topology optimization based on unified transfer matrix.

PubMed

Kim, Yoon Jae; Kim, Yoon Young

2010-10-01

This paper presents a numerical method for the optimization of the sequencing of solid panels, perforated panels and air gaps and their respective thickness for maximizing sound transmission loss and/or absorption. For the optimization, a method based on the topology optimization formulation is proposed. It is difficult to employ only the commonly-used material interpolation technique because the involved layers exhibit fundamentally different acoustic behavior. Thus, an optimization method formulation using a so-called unified transfer matrix is newly proposed. The key idea is to form elements of the transfer matrix such that interpolated elements by the layer design variables can be those of air, perforated and solid panel layers. The problem related to the interpolation is addressed and bench mark-type problems such as sound transmission or absorption maximization problems are solved to check the efficiency of the developed method.

A beta-ray spectrometer based on a two-or three silicon detector coincidence telescope

NASA Astrophysics Data System (ADS)

Horowitz, Y. S.; Weizman, Y.; Hirning, C. R.

1996-02-01

This report describes the operation of a beta-ray energy spectrometer based on a silicon detector telescope using two or three elements. The front detector is a planar, totally-depleted, silicon surface barrier detector that is 97 μm thick, the back detector is a room-temperature, lithium compensated, silicon detector that is 5000 μm thick, and the intermediate detector is similar to the front detector but 72 μm thick and intended to be used only in intense photon fields. The three detectors are mounted in a light-tight aluminum housing. The capability of the spectrometer to reject photons is based upon the fact that the incident photon will have a small probability of simultaneously losing detectable energy in two detectors, and an even smaller probability of losing detectable energy in all three detectors. Electrons will, however, almost always record measurable events in either the front two or all three detectors. A coincidence requirement between the detectors thus rejects photon induced events. With a 97 μm thick detector the lower energy coincidence threshold is approximately 110 keV. With an ultra-thin 40 μm thick front detector, and operated at 15°C, the spectrometer is capable of detecting even 60-70 keV electrons with a coincidence efficiency of 60%. The spectrometer has been used to measure beta radiation fields in CANDU reactor working environments, and the spectral information is intended to support dose algorithms for the LiF TLD chips used in the Ontario Hydro dosimetry program.

A fast-neutron detection detector based on fission material and large sensitive 4H silicon carbide Schottky diode detector

NASA Astrophysics Data System (ADS)

Liu, Linyue; Liu, Jinliang; Zhang, Jianfu; Chen, Liang; Zhang, Xianpeng; Zhang, Zhongbing; Ruan, Jinlu; Jin, Peng; Bai, Song; Ouyang, Xiaoping

2017-12-01

Silicon carbide radiation detectors are attractive in the measurement of the total numbers of pulsed fast neutrons emitted from nuclear fusion and fission devices because of high neutron-gamma discrimination and good radiation resistance. A fast-neutron detection system was developed based on a large-area 4H-SiC Schottky diode detector and a 235U fission target. Excellent pulse-height spectra of fission fragments induced by mono-energy deuterium-tritium (D-T) fusion neutrons and continuous energy fission neutrons were obtained. The detector is proven to be a good candidate for pulsed fast neutron detection in a complex radiation field.

Dynamics-based damage inspection of an aircraft wing panel

NASA Astrophysics Data System (ADS)

Pai, P. F.; Kim, Byeong-Seok; Chung, Jaycee H.

2003-08-01

This paper presents the dynamic characteristics and damage detection of an aircraft wing panel using a scanning laser vibrometer. The panel has an irregular shape with side lengths 16.44" x 14.82" x 11.10" x 5.38" x 14.22", different values of thickness (0.059" to 0.110"), and seven ribs on its backside. An in-house finite element code GESA is used to model the panel using 528 DKT plate elements and to obtain mode shapes and natural frequencies, and Operational Deflection Shapes (ODS) are measured using a scanning laser vibrometer. Results show that numerical dynamic characteristics agree well with the experimental ones. Six defects are created in the panel, including four small nuts glued on the backside and two small slots cut by electron discharge machining. Detection of the six defects is performed using the distributions of RMS velocities under high-frequency broadband periodic chirp excitations provided by a PZT patch and damage locating curves obtained by processing experimental ODSs using a newly developed BOudnary Effect Evaluation (BEE) method. The BEE method is non-destructive and model-independent; it processes experimental ODSs to reveal local boundary effects caused by defects. Experimental results show that the six small defects in the panel can be pinpointed using the approach.

Detector location selection based on VIP analysis in near-infrared detection of dural hematoma.

PubMed

Sun, Qiuming; Zhang, Yanjun; Ma, Jun; Tian, Feng; Wang, Huiquan; Liu, Dongyuan

2018-03-01

Detection of dural hematoma based on multi-channel near-infrared differential absorbance has the advantages of rapid and non-invasive detection. The location and number of detectors around the light source are critical for reducing the pathological characteristics of the prediction model on dural hematoma degree. Therefore, rational selection of detector numbers and their distances from the light source is very important. In this paper, a detector position screening method based on Variable Importance in the Projection (VIP) analysis is proposed. A preliminary modeling based on Partial Least Squares method (PLS) for the prediction of dural position μ a was established using light absorbance information from 30 detectors located 2.0-5.0 cm from the light source with a 0.1 cm interval. The mean relative error (MRE) of the dural position μ a prediction model was 4.08%. After VIP analysis, the number of detectors was reduced from 30 to 4 and the MRE of the dural position μ a prediction was reduced from 4.08% to 2.06% after the reduction in detector numbers. The prediction model after VIP detector screening still showed good prediction of the epidural position μ a . This study provided a new approach and important reference on the selection of detector location in near-infrared dural hematoma detection.

Gamma-ray Irradiation Effects on InAs/GaSb-based nBn IR Detector

DTIC Science & Technology

2011-01-01

very low noise performance. When properly passivated, conventional mercury cadmium telluride ( MCT )?based infrared detectors have been shown to...Gamma-ray Irradiation Effects on InAs/GaSb-based nBn IR Detector Vincent M. Cowan*1, Christian P. Morath1, Seth M. Swift1, Stephen Myers2...2Center for High Technology Materials, University of New Mexico, Albuquerque, NM 87106, USA ABSTRACT IR detectors operated in a space environment are

Working Gas Selection of the Honeycomb Converter-Based Neutron Detector

NASA Astrophysics Data System (ADS)

Fang, Zhujun; Yang, Yigang; Li, Yulan; Wang, Xuewu

2017-07-01

To reduce the manufacturing difficulty and improve the robustness of traditional boron-lined detectors that may replace the 3He counter, the honeycomb neutron converter-based gaseous neutron detector has been proposed. A drift electric field is applied to drive electrons ionized by α or 7Li after the 10B(n, α)7Li reaction from their origination positions to the incident surface of the gas electron multiplier (GEM), which multiplies electrons and forms the neutron signal. As the working gas affects the energy deposition of α or 7Li, the transverse diffusion of electrons in the migration process, as well as the multiplication of electrons in the GEM detector, the working gas selection of the honeycomb converter-based detector would be very important. Fourteen different working gases are investigated in detail through simulation research. Four working gases, Ar:iC4H10:CF4 = 90:7:3, Ar:CO2 = 95:5, Ar:CH4 = 90:10, and Ar:DME = 95:5, are experimentally tested. Both the simulation and experimental results demonstrate that working gases of Ar:iC4H10:CF4 = 90:7:3, Ar:CO2 = 95:5, and Ar:DME = 95:5 show good performances benefitting from both the large stopping powers of α or 7Li and the small transverse diffusion coefficients of electrons. The simulation results indicate that the detection efficiency with one of the three gases is 1.33 to 1.48 times the Ar:CH4 = 90:10, while the experimental results demonstrate that there is 1.34-1.49 times of the detection efficiency. The research in this paper helps improve the performance of the honeycomb converter-based neutron detector.

A GridPix-based X-ray detector for the CAST experiment

NASA Astrophysics Data System (ADS)

Krieger, C.; Kaminski, J.; Lupberger, M.; Desch, K.

2017-09-01

The CAST experiment has been searching for axions and axion-like particles for more than 10 years. The continuous improvements in the detector designs have increased the physics reach of the experiment far beyond what was originally conceived. As part of this development, a new detector based on a GridPix readout had been developed in 2014 and was mounted on the CAST experiment during the end of the data taking period of 2014 and the complete period in 2015. We report on the detector design, its advantages and the performance during both periods.

Studying radiation hardness of a cadmium tungstate crystal based radiation detector

NASA Astrophysics Data System (ADS)

Shtein, M. M.; Smekalin, L. F.; Stepanov, S. A.; Zatonov, I. A.; Tkacheva, T. V.; Usachev, E. Yu

2016-06-01

The given article considers radiation hardness of an X-ray detector used in production of non-destructive testing instruments and inspection systems. In the course of research, experiments were carried out to estimate radiation hardness of a detector based on cadmium tungstate crystal and its structural components individually. The article describes a layout of an experimental facility that was used for measurements of radiation hardness. The radiation dose dependence of the photodiode current is presented, when it is excited by a light flux of a scintillator or by an external light source. Experiments were carried out to estimate radiation hardness of two types of optical glue used in detector production; they are based on silicon rubber and epoxy. With the help of a spectrophotometer and cobalt gun, each of the glue samples was measured for a relative light transmission factor with different wavelengths, depending on the radiation dose. The obtained data are presented in a comprehensive analysis of the results. It was determined, which of the glue samples is most suitable for production of detectors working under exposure to strong radiation.

High-Performance LWIR Superlattice Detectors and FPA Based on CBIRD Design

NASA Technical Reports Server (NTRS)

Soibel, Alexander; Nguyen, Jean; Khoshakhlagh, Arezou; Rafol, Sir B.; Hoeglund, Linda; Keo, Sam A.; Mumolo, Jason M.; Liu, John; Liao, Anna; Ting, David Z.-Y.;

A general panel sizing computer code and its application to composite structural panels

NASA Technical Reports Server (NTRS)

Anderson, M. S.; Stroud, W. J.

1978-01-01

A computer code for obtaining the dimensions of optimum (least mass) stiffened composite structural panels is described. The procedure, which is based on nonlinear mathematical programming and a rigorous buckling analysis, is applicable to general cross sections under general loading conditions causing buckling. A simplified method of accounting for bow-type imperfections is also included. Design studies in the form of structural efficiency charts for axial compression loading are made with the code for blade and hat stiffened panels. The effects on panel mass of imperfections, material strength limitations, and panel stiffness requirements are also examined. Comparisons with previously published experimental data show that accounting for imperfections improves correlation between theory and experiment.

FPGA-based GEM detector signal acquisition for SXR spectroscopy system

NASA Astrophysics Data System (ADS)

Wojenski, A.; Pozniak, K. T.; Kasprowicz, G.; Kolasinski, P.; Krawczyk, R.; Zabolotny, W.; Chernyshova, M.; Czarski, T.; Malinowski, K.

2016-11-01

The presented work is related to the Gas Electron Multiplier (GEM) detector soft X-ray spectroscopy system for tokamak applications. The used GEM detector has one-dimensional, 128 channel readout structure. The channels are connected to the radiation-hard electronics with configurable analog stage and fast ADCs, supporting speeds of 125 MSPS for each channel. The digitalized data is sent directly to the FPGAs using fast serial links. The preprocessing algorithms are implemented in the FPGAs, with the data buffering made in the on-board 2Gb DDR3 memory chips. After the algorithmic stage, the data is sent to the Intel Xeon-based PC for further postprocessing using PCI-Express link Gen 2. For connection of multiple FPGAs, PCI-Express switch 8-to-1 was designed. The whole system can support up to 2048 analog channels. The scope of the work is an FPGA-based implementation of the recorder of the raw signal from GEM detector. Since the system will work in a very challenging environment (neutron radiation, intense electro-magnetic fields), the registered signals from the GEM detector can be corrupted. In the case of the very intense hot plasma radiation (e.g. laser generated plasma), the registered signals can overlap. Therefore, it is valuable to register the raw signals from the GEM detector with high number of events during soft X-ray radiation. The signal analysis will have the direct impact on the implementation of photon energy computation algorithms. As the result, the system will produce energy spectra and topological distribution of soft X-ray radiation. The advanced software was developed in order to perform complex system startup and monitoring of hardware units. Using the array of two one-dimensional GEM detectors it will be possible to perform tomographic reconstruction of plasma impurities radiation in the SXR region.

45 CFR 1801.23 - Recommendation by panel.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Recommendation by panel. 1801.23 Section 1801.23... HARRY S. TRUMAN SCHOLARSHIP PROGRAM The Competition § 1801.23 Recommendation by panel. (a) Each Panel is... recommend additional Scholars from the States in its region. (b) A panel's recommendations are based on the...

45 CFR 1801.23 - Recommendation by panel.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 4 2011-10-01 2011-10-01 false Recommendation by panel. 1801.23 Section 1801.23... HARRY S. TRUMAN SCHOLARSHIP PROGRAM The Competition § 1801.23 Recommendation by panel. (a) Each Panel is... recommend additional Scholars from the States in its region. (b) A panel's recommendations are based on the...

Instruments, Detectors and the Future of Astronomy with Large Ground Based Telescopes

NASA Astrophysics Data System (ADS)

Simons, Douglas A.; Amico, Paola; Baade, Dietrich; Barden, Sam; Campbell, Randall; Finger, Gert; Gilmore, Kirk; Gredel, Roland; Hickson, Paul; Howell, Steve; Hubin, Norbert; Kaufer, Andreas; Kohley, Ralf; MacQueen, Philip; Markelov, Sergej; Merrill, Mike; Miyazaki, Satoshi; Nakaya, Hidehiko; O'Donoghue, Darragh; Oliva, Tino; Richichi, Andrea; Salmon, Derrick; Schmidt, Ricardo; Su, Hongjun; Tulloch, Simon; García Vargas, Maria Luisa; Wagner, R. Mark; Wiecha, Olivier; Ye, Binxun

2005-01-01

Results of a survey of instrumentation and detector systems, either currently deployed or planned for use at telescopes larger than 3.5 m, in ground based observatories world-wide, are presented. This survey revealed a number of instrumentation design trends at optical, near, and mid-infrared wavelengths. Some of the most prominent trends include the development of vastly larger optical detector systems (> 109 pixels) than anything built to date, and the frequent use of mosaics of near-infrared detectors - something that was quite rare only a decade ago in astronomy. Some future science applications for detectors are then explored, in an attempt to build a bridge between current detectors and what will be needed to support the research ambitions of astronomers in the future.

Neutron multiplicity ,easurements With 3He alternative: Straw neutron detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Meade, John A.

Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as “ship effect”) and to the complicated nature of the neutron scattering in that environment. In this study, a prototype neutron detector was built using 10B as the converter in a special form factor called “straws” that would address the above problems by looking into the details of multiplicity distributions ofmore » neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B 4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and developed a data acquisition (DAQ) system to collect

Neutron multiplicity measurements with 3He alternative: Straw neutron detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukhopadhyay, Sanjoy; Wolff, Ronald; Detwiler, Ryan

Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as ‘‘ship effect ’’) and to the complicated nature of the neutron scattering in that environment. A prototype neutron detector was built using 10B as the converter in a special form factor called ‘‘straws’’ that would address the above problems by looking into the details of multiplicity distributions of neutrons originatingmore » from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B 4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and developed a data acquisition (DAQ) system to collect

Neutron multiplicity ,easurements With 3He alternative: Straw neutron detectors

DOE PAGES

Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Meade, John A.; ...

2015-01-27

Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as “ship effect”) and to the complicated nature of the neutron scattering in that environment. In this study, a prototype neutron detector was built using 10B as the converter in a special form factor called “straws” that would address the above problems by looking into the details of multiplicity distributions ofmore » neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B 4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and developed a data acquisition (DAQ) system to collect

Performance evaluation of a direct-conversion flat-panel detector system in imaging and quality assurance for a high-dose-rate 192Ir source

NASA Astrophysics Data System (ADS)

Miyahara, Yoshinori; Hara, Yuki; Nakashima, Hiroto; Nishimura, Tomonori; Itakura, Kanae; Inomata, Taisuke; Kitagaki, Hajime

2018-03-01

In high-dose-rate (HDR) brachytherapy, a direct-conversion flat-panel detector (d-FPD) clearly depicts a 192Ir source without image halation, even under the emission of high-energy gamma rays. However, it was unknown why iridium is visible when using a d-FPD. The purpose of this study was to clarify the reasons for visibility of the source core based on physical imaging characteristics, including the modulation transfer functions (MTF), noise power spectral (NPS), contrast transfer functions, and linearity of d-FPD to high-energy gamma rays. The acquired data included: x-rays, [X]; gamma rays, [γ] dual rays (X  +  γ), [D], and subtracted data for depicting the source ([D]  -  [γ]). In the quality assurance (QA) test for the positional accuracy of a source core, the coordinates of each dwelling point were compared between the planned and actual source core positions using a CT/MR-compatible ovoid applicator and a Fletcher-Williamson applicator. The profile curves of [X] and ([D]  -  [γ]) matched well on MTF and NPS. The contrast resolutions of [D] and [X] were equivalent. A strongly positive linear correlation was found between the output data of [γ] and source strength (r 2  >  0.99). With regard to the accuracy of the source core position, the largest coordinate difference (3D distance) was noted at the maximum curvature of the CT/MR-compatible ovoid and Fletcher-Williamson applicators, showing 1.74  ±  0.02 mm and 1.01  ±  0.01 mm, respectively. A d-FPD system provides high-quality images of a source, even when high-energy gamma rays are emitted to the detector, and positional accuracy tests with clinical applicators are useful in identifying source positions (source movements) within the applicator for QA.

Boron-coated straws as a replacement for 3He-based neutron detectors

NASA Astrophysics Data System (ADS)

Lacy, Jeffrey L.; Athanasiades, Athanasios; Sun, Liang; Martin, Christopher S.; Lyons, Tom D.; Foss, Michael A.; Haygood, Hal B.

2011-10-01

US and international government efforts to equip major seaports with large area neutron detectors, aimed to intercept the smuggling of nuclear materials, have precipitated a critical shortage of 3He gas. It is estimated that the annual demand of 3He for US security applications alone is more than the worldwide supply. This is strongly limiting the prospects of neutron science, safeguards, and other applications that rely heavily on 3He-based detectors. Clearly, alternate neutron detection technologies that can support large sensitive areas, and have low gamma sensitivity and low cost must be developed. We propose a low-cost technology based on long copper tubes (straws), coated on the inside with a thin layer of 10B-enriched boron carbide ( 10B 4C). In addition to the high abundance of boron on Earth and low cost of 10B enrichment, the boron-coated straw (BCS) detector offers distinct advantages over conventional 3He-based detectors, and alternate technologies such as 10BF 3 tubes and 10B-coated rigid tubes. These include better distribution inside moderator assemblies, many-times faster electronic signals, no pressurization, improved gamma-ray rejection, no toxic or flammable gases, and ease of serviceability. We present the performance of BCS detectors dispersed in a solid plastic moderator to address the need for portal monitoring. The design adopts the outer dimensions of currently deployed 3He-based monitors, but takes advantage of the small BCS diameter to achieve a more uniform distribution of neutron converter throughout the moderating material. We show that approximately 63 BCS detectors, each 205 cm long, distributed inside the moderator, can match or exceed the detection efficiency of typical monitors fitted with a 5 cm diameter 3He tube, 187 cm long, pressurized to 3 atm.

A Divergence Median-based Geometric Detector with A Weighted Averaging Filter

NASA Astrophysics Data System (ADS)

Hua, Xiaoqiang; Cheng, Yongqiang; Li, Yubo; Wang, Hongqiang; Qin, Yuliang

2018-01-01

To overcome the performance degradation of the classical fast Fourier transform (FFT)-based constant false alarm rate detector with the limited sample data, a divergence median-based geometric detector on the Riemannian manifold of Heimitian positive definite matrices is proposed in this paper. In particular, an autocorrelation matrix is used to model the correlation of sample data. This method of the modeling can avoid the poor Doppler resolution as well as the energy spread of the Doppler filter banks result from the FFT. Moreover, a weighted averaging filter, conceived from the philosophy of the bilateral filtering in image denoising, is proposed and combined within the geometric detection framework. As the weighted averaging filter acts as the clutter suppression, the performance of the geometric detector is improved. Numerical experiments are given to validate the effectiveness of our proposed method.

High-Performance LWIR Superlattice Detectors and FPA Based on CBIRD Design

NASA Technical Reports Server (NTRS)

Soibel, Alexander; Nguyen, Jean; Rafol, Sir B.; Liao, Anna; Hoeglund, Linda; Khoshakhlagh, Arezou; Keo, Sam A.; Mumolo, Jason M.; Liu, John; Ting, David Z.-Y.;

High-Performance LWIR Superlattice Detectors and FPA Based on CBIRD Design

NASA Technical Reports Server (NTRS)

Soibel, Alexander; Nguyen, Jean; Rafol, Sir B.; Liao, Anna; Hoeglund, Linda; Khoshakhlagh, Arezou; Keo, Sam A.; Mumolo, Jason M.; Liu, John; Ting, David Z.-Y.;

A risk-based approach to flammable gas detector spacing.

PubMed

Defriend, Stephen; Dejmek, Mark; Porter, Leisa; Deshotels, Bob; Natvig, Bernt

2008-11-15

Flammable gas detectors allow an operating company to address leaks before they become serious, by automatically alarming and by initiating isolation and safe venting. Without effective gas detection, there is very limited defense against a flammable gas leak developing into a fire or explosion that could cause loss of life or escalate to cascading failures of nearby vessels, piping, and equipment. While it is commonly recognized that some gas detectors are needed in a process plant containing flammable gas or volatile liquids, there is usually a question of how many are needed. The areas that need protection can be determined by dispersion modeling from potential leak sites. Within the areas that must be protected, the spacing of detectors (or alternatively, number of detectors) should be based on risk. Detector design can be characterized by spacing criteria, which is convenient for design - or alternatively by number of detectors, which is convenient for cost reporting. The factors that influence the risk are site-specific, including process conditions, chemical composition, number of potential leak sites, piping design standards, arrangement of plant equipment and structures, design of isolation and depressurization systems, and frequency of detector testing. Site-specific factors such as those just mentioned affect the size of flammable gas cloud that must be detected (within a specified probability) by the gas detection system. A probability of detection must be specified that gives a design with a tolerable risk of fires and explosions. To determine the optimum spacing of detectors, it is important to consider the probability that a detector will fail at some time and be inoperative until replaced or repaired. A cost-effective approach is based on the combined risk from a representative selection of leakage scenarios, rather than a worst-case evaluation. This means that probability and severity of leak consequences must be evaluated together. In marine and

Analysis of Cadmium Based Neutron Detector Configurations

NASA Astrophysics Data System (ADS)

James, Brian; Rees, Lawrence; Czirr, J. Bart

2012-10-01

Due to national security concerns pertaining to the smuggling of special nuclear materials and a small supply of He-3 for use in neutron detectors, there is currently a need for a new kind of neutron detector. Using Monte Carlo techniques I have studied the neutron capture efficiency of an array of cadmium wedge detectors in the presence of a californium source. By using varying numbers of wedges and comparing their capture ratios we will be better able to design future detectors.

Sensor Modelling for the ’Cyclops’ Focal Plane Detector Array Based Technology Demonstrator

DTIC Science & Technology

1992-12-01

Detector Array IFOV Instantaneous field of view IRFPDA Infrared Focal Plane Detector Array LWIR Long-Wave Infrared 0 MCT Mercury Cadmium Telluride MTF...scale focal plane detector array (FPDA). The sensor system operates in the long-wave infrared ( LWIR ) spectral region. The detector array consists of...charge transfer inefficiencies in the readout circuitry. The performance of the HgCdTe FPDA based sensor is limited by the nonuniformity of the

Low pressure ion chromatography with a low cost paired emitter-detector diode based detector for the determination of alkaline earth metals in water samples.

PubMed

Barron, Leon; Nesterenko, Pavel N; Diamond, Dermot; O'Toole, Martina; Lau, King Tong; Paull, Brett

2006-09-01

The use of a low pressure ion chromatograph based upon short (25 mm x 4.6 mm) surfactant coated monolithic columns and a low cost paired emitter-detector diode (PEDD) based detector, for the determination of alkaline earth metals in aqueous matrices is presented. The system was applied to the separation of magnesium, calcium, strontium and barium in less than 7min using a 0.15M KCl mobile phase at pH 3, with post-column reaction detection at 570 nm using o-cresolphthalein complexone. A comparison of the performance of the PEDD detector with a standard laboratory absorbance detector is shown, with limits of detection for magnesium and calcium using the low cost PEDD detector equal to 0.16 and 0.23 mg L(-1), respectively. Finally, the developed system was used for the determination of calcium and magnesium in a commercial spring water sample.

Simulation of the CRIPT Detector

DTIC Science & Technology

2015-03-01

National Defence, 2015 c© Sa Majesté la Reine (en droit du Canada), telle que réprésentée par le ministre de la Défense nationale, 2015 Abstract The...iron slabs of the spectrometer. The red plates are the panels containing the scintillator bars. 3 3 Monte Carlo Geometry The geometry of the detector is...instead of hollow), • parts were in wrong location (eg. spectrometer iron plates). To fix this, Computer Aided Design ( CAD ) drawings were provided for

Optimization of dual-energy subtraction chest radiography by use of a direct-conversion flat-panel detector system.

PubMed

Fukao, Mari; Kawamoto, Kiyosumi; Matsuzawa, Hiroaki; Honda, Osamu; Iwaki, Takeshi; Doi, Tsukasa

2015-01-01

We aimed to optimize the exposure conditions in the acquisition of soft-tissue images using dual-energy subtraction chest radiography with a direct-conversion flat-panel detector system. Two separate chest images were acquired at high- and low-energy exposures with standard or thick chest phantoms. The high-energy exposure was fixed at 120 kVp with the use of an auto-exposure control technique. For the low-energy exposure, the tube voltages and entrance surface doses ranged 40-80 kVp and 20-100 % of the dose required for high-energy exposure, respectively. Further, a repetitive processing algorithm was used for reduction of the image noise generated by the subtraction process. Seven radiology technicians ranked soft-tissue images, and these results were analyzed using the normalized-rank method. Images acquired at 60 kVp were of acceptable quality regardless of the entrance surface dose and phantom size. Using a repetitive processing algorithm, the minimum acceptable doses were reduced from 75 to 40 % for the standard phantom and to 50 % for the thick phantom. We determined that the optimum low-energy exposure was 60 kVp at 50 % of the dose required for the high-energy exposure. This allowed the simultaneous acquisition of standard radiographs and soft-tissue images at 1.5 times the dose required for a standard radiograph, which is significantly lower than the values reported previously.

Flexible amorphous silicon PIN diode x-ray detectors

NASA Astrophysics Data System (ADS)

Marrs, Michael; Bawolek, Edward; Smith, Joseph T.; Raupp, Gregory B.; Morton, David

2013-05-01

A low temperature amorphous silicon (a-Si) thin film transistor (TFT) and amorphous silicon PIN photodiode technology for flexible passive pixel detector arrays has been developed using active matrix display technology. The flexible detector arrays can be conformed to non-planar surfaces with the potential to detect x-rays or other radiation with an appropriate conversion layer. The thin, lightweight, and robust backplanes may enable the use of highly portable x-ray detectors for use in the battlefield or in remote locations. We have fabricated detector arrays up to 200 millimeters along the diagonal on a Gen II (370 mm x 470 mm rectangular substrate) using plasma enhanced chemical vapor deposition (PECVD) a-Si as the active layer and PECVD silicon nitride (SiN) as the gate dielectric and passivation. The a-Si based TFTs exhibited an effective saturation mobility of 0.7 cm2/V-s, which is adequate for most sensing applications. The PIN diode material was fabricated using a low stress amorphous silicon (a-Si) PECVD process. The PIN diode dark current was 1.7 pA/mm2, the diode ideality factor was 1.36, and the diode fill factor was 0.73. We report on the critical steps in the evolution of the backplane process from qualification of the low temperature (180°C) TFT and PIN diode process on the 150 mm pilot line, the transfer of the process to flexible plastic substrates, and finally a discussion and demonstration of the scale-up to the Gen II (370 x 470 mm) panel scale pilot line.

Signal processing for a single detector MOEMS based NIR micro spectrometer

NASA Astrophysics Data System (ADS)

Heberer, Andreas; Grüger, Heinrich; Zimmer, Fabian; Schenk, Harald; Kenda, Andreas; Frank, Albert; Scherf, Werner

2005-10-01

The examination of spectra in the NIR range is necessary for applications like process control, element analysis or medical systems. Typically integrated NIR spectrometers are based on optical setups with diffraction grating and detector arrays. The main disadvantage is price and availability of NIR array InGaAs-based detectors. The implementation of a scanning grating chip realized in a MOEMS technology which integrates the diffractive element makes it possible to detect spectra with single detectors time resolved. Either simple InGaAs photodiodes or cooled detectors may be used. The set up is a shrinked Czerny-Turner spectrometer. The light is coupled in by an optical fibre. After focussing the light passes the scanning grating moving at 150-500 Hz in a sinusoidal way. There it is split off in the different wavelength, the monochrome intensity is caught by a second mirror and led to the detector. The detector signal is amplified by a transimpedance stage and converted to digital with 12 bit resolution. The main part of the signal processing is done by a digital signal processor, which is used to unfold the sinusoidal position and calculate the final spectra. The data rate can be up to 3 MHz, then a spectrum is acquired every 2ms by using a 500Hz Mirror. Using the DSP, the spectrometer can operate autarkic without any PC. Then the spectrum is display on a 160 x 80 pixel graphic LCD. A keypad is used to control the functions. For communication a USB port is included, additional interfaces can be realized by a 16-pin expansion port, which is freely programmable, by the system firmware.

Multicenter validation of cancer gene panel-based next-generation sequencing for translational research and molecular diagnostics.

PubMed

Hirsch, B; Endris, V; Lassmann, S; Weichert, W; Pfarr, N; Schirmacher, P; Kovaleva, V; Werner, M; Bonzheim, I; Fend, F; Sperveslage, J; Kaulich, K; Zacher, A; Reifenberger, G; Köhrer, K; Stepanow, S; Lerke, S; Mayr, T; Aust, D E; Baretton, G; Weidner, S; Jung, A; Kirchner, T; Hansmann, M L; Burbat, L; von der Wall, E; Dietel, M; Hummel, M

2018-04-01

The simultaneous detection of multiple somatic mutations in the context of molecular diagnostics of cancer is frequently performed by means of amplicon-based targeted next-generation sequencing (NGS). However, only few studies are available comparing multicenter testing of different NGS platforms and gene panels. Therefore, seven partner sites of the German Cancer Consortium (DKTK) performed a multicenter interlaboratory trial for targeted NGS using the same formalin-fixed, paraffin-embedded (FFPE) specimen of molecularly pre-characterized tumors (n = 15; each n = 5 cases of Breast, Lung, and Colon carcinoma) and a colorectal cancer cell line DNA dilution series. Detailed information regarding pre-characterized mutations was not disclosed to the partners. Commercially available and custom-designed cancer gene panels were used for library preparation and subsequent sequencing on several devices of two NGS different platforms. For every case, centrally extracted DNA and FFPE tissue sections for local processing were delivered to each partner site to be sequenced with the commercial gene panel and local bioinformatics. For cancer-specific panel-based sequencing, only centrally extracted DNA was analyzed at seven sequencing sites. Subsequently, local data were compiled and bioinformatics was performed centrally. We were able to demonstrate that all pre-characterized mutations were re-identified correctly, irrespective of NGS platform or gene panel used. However, locally processed FFPE tissue sections disclosed that the DNA extraction method can affect the detection of mutations with a trend in favor of magnetic bead-based DNA extraction methods. In conclusion, targeted NGS is a very robust method for simultaneous detection of various mutations in FFPE tissue specimens if certain pre-analytical conditions are carefully considered.

Near midplane scintillator-based fast ion loss detector on DIII-D.

PubMed

Chen, X; Fisher, R K; Pace, D C; García-Muñoz, M; Chavez, J A; Heidbrink, W W; Van Zeeland, M A

2012-10-01

A new scintillator-based fast-ion loss detector (FILD) installed near the outer midplane of the plasma has been commissioned on DIII-D. This detector successfully measures coherent fast ion losses produced by fast-ion driven instabilities (≤500 kHz). Combined with the first FILD at ∼45° below the outer midplane [R. K. Fisher, et al., Rev. Sci. Instrum. 81, 10D307 (2010)], the two-detector system measures poloidal variation of losses. The phase space sensitivity of the new detector (gyroradius r(L) ∼ [1.5-8] cm and pitch angle α ∼ [35°-85°]) is calibrated using neutral beam first orbit loss measurements. Since fast ion losses are localized poloidally, having two FILDs at different poloidal locations allows for the study of losses over a wider range of plasma shapes and types of loss orbits.

Integrated radiotherapy imaging system (IRIS): design considerations of tumour tracking with linac gantry-mounted diagnostic x-ray systems with flat-panel detectors

NASA Astrophysics Data System (ADS)

Berbeco, Ross I.; Jiang, Steve B.; Sharp, Gregory C.; Chen, George T. Y.; Mostafavi, Hassan; Shirato, Hiroki

2004-01-01

The design of an integrated radiotherapy imaging system (IRIS), consisting of gantry mounted diagnostic (kV) x-ray tubes and fast read-out flat-panel amorphous-silicon detectors, has been studied. The system is meant to be capable of three main functions: radiographs for three-dimensional (3D) patient set-up, cone-beam CT and real-time tumour/marker tracking. The goal of the current study is to determine whether one source/panel pair is sufficient for real-time tumour/marker tracking and, if two are needed, the optimal position of each relative to other components and the isocentre. A single gantry-mounted source/imager pair is certainly capable of the first two of the three functions listed above and may also be useful for the third, if combined with prior knowledge of the target's trajectory. This would be necessary because only motion in two dimensions is visible with a single imager/source system. However, with previously collected information about the trajectory, the third coordinate may be derived from the other two with sufficient accuracy to facilitate tracking. This deduction of the third coordinate can only be made if the 3D tumour/marker trajectory is consistent from fraction to fraction. The feasibility of tumour tracking with one source/imager pair has been theoretically examined here using measured lung marker trajectory data for seven patients from multiple treatment fractions. The patients' selection criteria include minimum mean amplitudes of the tumour motions greater than 1 cm peak-to-peak. The marker trajectory for each patient was modelled using the first fraction data. Then for the rest of the data, marker positions were derived from the imager projections at various gantry angles and compared with the measured tumour positions. Our results show that, due to the three dimensionality and irregular trajectory characteristics of tumour motion, on a fraction-to-fraction basis, a 'monoscopic' system (single source/imager) is inadequate for

A robust approach to measuring the detective quantum efficiency of radiographic detectors in a clinical setting

NASA Astrophysics Data System (ADS)

McDonald, Michael C.; Kim, H. K.; Henry, J. R.; Cunningham, I. A.

2012-03-01

The detective quantum efficiency (DQE) is widely accepted as a primary measure of x-ray detector performance in the scientific community. A standard method for measuring the DQE, based on IEC 62220-1, requires the system to have a linear response meaning that the detector output signals are proportional to the incident x-ray exposure. However, many systems have a non-linear response due to characteristics of the detector, or post processing of the detector signals, that cannot be disabled and may involve unknown algorithms considered proprietary by the manufacturer. For these reasons, the DQE has not been considered as a practical candidate for routine quality assurance testing in a clinical setting. In this article we described a method that can be used to measure the DQE of both linear and non-linear systems that employ only linear image processing algorithms. The method was validated on a Cesium Iodide based flat panel system that simultaneously stores a raw (linear) and processed (non-linear) image for each exposure. It was found that the resulting DQE was equivalent to a conventional standards-compliant DQE with measurement precision, and the gray-scale inversion and linear edge enhancement did not affect the DQE result. While not IEC 62220-1 compliant, it may be adequate for QA programs.

Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed structural panels in bending

Treesearch

Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

2017-01-01

This paper presents an analysis of 3-dimensional engineered structural panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model...

An imaging-based photometric and colorimetric measurement method for characterizing OLED panels for lighting applications

NASA Astrophysics Data System (ADS)

Zhu, Yiting; Narendran, Nadarajah; Tan, Jianchuan; Mou, Xi

2014-09-01

The organic light-emitting diode (OLED) has demonstrated its novelty in displays and certain lighting applications. Similar to white light-emitting diode (LED) technology, it also holds the promise of saving energy. Even though the luminous efficacy values of OLED products have been steadily growing, their longevity is still not well understood. Furthermore, currently there is no industry standard for photometric and colorimetric testing, short and long term, of OLEDs. Each OLED manufacturer tests its OLED panels under different electrical and thermal conditions using different measurement methods. In this study, an imaging-based photometric and colorimetric measurement method for OLED panels was investigated. Unlike an LED that can be considered as a point source, the OLED is a large form area source. Therefore, for an area source to satisfy lighting application needs, it is important that it maintains uniform light level and color properties across the emitting surface of the panel over a long period. This study intended to develop a measurement procedure that can be used to test long-term photometric and colorimetric properties of OLED panels. The objective was to better understand how test parameters such as drive current or luminance and temperature affect the degradation rate. In addition, this study investigated whether data interpolation could allow for determination of degradation and lifetime, L70, at application conditions based on the degradation rates measured at different operating conditions.

The slip-and-slide algorithm: a refinement protocol for detector geometry

PubMed Central

Ginn, Helen Mary; Stuart, David Ian

2017-01-01

Geometry correction is traditionally plagued by mis-fitting of correlated parameters, leading to local minima which prevent further improvements. Segmented detectors pose an enhanced risk of mis-fitting: even a minor confusion of detector distance and panel separation can prevent improvement in data quality. The slip-and-slide algorithm breaks down effects of the correlated parameters and their associated target functions in a fundamental shift in the approach to the problem. Parameters are never refined against the components of the data to which they are insensitive, providing a dramatic boost in the exploitation of information from a very small number of diffraction patterns. This algorithm can be applied to exploit the adherence of the spot-finding results prior to indexing to a given lattice using unit-cell dimensions as a restraint. Alternatively, it can be applied to the predicted spot locations and the observed reflection positions after indexing from a smaller number of images. Thus, the indexing rate can be boosted by 5.8% using geometry refinement from only 125 indexed patterns or 500 unindexed patterns. In one example of cypovirus type 17 polyhedrin diffraction at the Linac Coherent Light Source, this geometry refinement reveals a detector tilt of 0.3° (resulting in a maximal Z-axis error of ∼0.5 mm from an average detector distance of ∼90 mm) whilst treating all panels independently. Re-indexing and integrating with updated detector geometry reduces systematic errors providing a boost in anomalous signal of sulfur atoms by 20%. Due to the refinement of decoupled parameters, this geometry method also reaches convergence. PMID:29091058

Single-layer and dual-layer contrast-enhanced mammography using amorphous selenium flat panel detectors

NASA Astrophysics Data System (ADS)

Allec, N.; Abbaszadeh, S.; Karim, K. S.

2011-09-01

The accumulation of injected contrast agents allows the image enhancement of lesions through the use of contrast-enhanced mammography. In this technique, the combination of two acquired images is used to create an enhanced image. There exist several methods to acquire the images to be combined, which include dual energy subtraction using a single detection layer that suffers from motion artifacts due to patient motion between image acquisition. To mitigate motion artifacts, a detector composed of two layers may be used to simultaneously acquire the low and high energy images. In this work, we evaluate both of these methods using amorphous selenium as the detection material to find the system parameters (tube voltage, filtration, photoconductor thickness and relative intensity ratio) leading to the optimal performance. We then compare the performance of the two detectors under the variation of contrast agent concentration, tumor size and dose. The detectability was found to be most comparable at the lower end of the evaluated factors. The single-layer detector not only led to better contrast, due to its greater spectral separation capabilities, but also had lower quantum noise. The single-layer detector was found to have a greater detectability by a factor of 2.4 for a 2.5 mm radius tumor having a contrast agent concentration of 1.5 mg ml-1 in a 4.5 cm thick 50% glandular breast. The inclusion of motion artifacts in the comparison is part of ongoing research efforts.

Single-layer and dual-layer contrast-enhanced mammography using amorphous selenium flat panel detectors.

PubMed

Allec, N; Abbaszadeh, S; Karim, K S

2011-09-21

The accumulation of injected contrast agents allows the image enhancement of lesions through the use of contrast-enhanced mammography. In this technique, the combination of two acquired images is used to create an enhanced image. There exist several methods to acquire the images to be combined, which include dual energy subtraction using a single detection layer that suffers from motion artifacts due to patient motion between image acquisition. To mitigate motion artifacts, a detector composed of two layers may be used to simultaneously acquire the low and high energy images. In this work, we evaluate both of these methods using amorphous selenium as the detection material to find the system parameters (tube voltage, filtration, photoconductor thickness and relative intensity ratio) leading to the optimal performance. We then compare the performance of the two detectors under the variation of contrast agent concentration, tumor size and dose. The detectability was found to be most comparable at the lower end of the evaluated factors. The single-layer detector not only led to better contrast, due to its greater spectral separation capabilities, but also had lower quantum noise. The single-layer detector was found to have a greater detectability by a factor of 2.4 for a 2.5 mm radius tumor having a contrast agent concentration of 1.5 mg ml(-1) in a 4.5 cm thick 50% glandular breast. The inclusion of motion artifacts in the comparison is part of ongoing research efforts.

Ottawa Panel evidence-based clinical practice guidelines for therapeutic exercise in the management of hip osteoarthritis.

PubMed

Brosseau, Lucie; Wells, George A; Pugh, Arlanna G; Smith, Christine Am; Rahman, Prinon; Àlvarez Gallardo, Inmaculada C; Toupin-April, Karine; Loew, Laurianne; De Angelis, Gino; Cavallo, Sabrina; Taki, Jade; Marcotte, Rachel; Fransen, Marlene; Hernandez-Molina, Gabriela; Kenny, Glen P; Regnaux, Jean-Philippe; Lefevre-Colau, Marie-Martine; Brooks, Sydney; Laferriere, Lucie; McLean, Linda; Longchamp, Guy

2016-10-01

The primary objective is to identify effective land-based therapeutic exercise interventions and provide evidence-based recommendations for managing hip osteoarthritis. A secondary objective is to develop an Ottawa Panel evidence-based clinical practice guideline for hip osteoarthritis. The search strategy and modified selection criteria from a Cochrane review were used. Studies included hip osteoarthritis patients in comparative controlled trials with therapeutic exercise interventions. An Expert Panel arrived at a Delphi survey consensus to endorse the recommendations. The Ottawa Panel hierarchical alphabetical grading system (A, B, C+, C, D, D+, or D-) considered the study design (level I: randomized controlled trial and level II: controlled clinical trial), statistical significance (p < 0.5), and clinical importance (⩾15% improvement). Four high-quality studies were included, which demonstrated that variations of strength training, stretching, and flexibility exercises are generally effective for improving the management of hip osteoarthritis. Strength training exercises displayed the greatest improvements for pain (Grade A), disability (Grades A and C+), physical function (Grade A), stiffness (Grade A), and range of motion (Grade A) within a short time period (8-24 weeks). Stretching also greatly improved physical function (Grade A), and flexibility exercises improved pain (Grade A), range of motion (Grade A), physical function (Grade A), and stiffness (Grade C+). The Ottawa Panel recommends land-based therapeutic exercise, notably strength training, for management of hip osteoarthritis in reducing pain, stiffness and self-reported disability, and improving physical function and range of motion. © The Author(s) 2015.

Driver-Array Based Flat-Panel Loudspeakers: Theoretical Background and Design Guidelines

NASA Astrophysics Data System (ADS)

Anderson, David Allan

This thesis relates to the simulation and design of flat-panel loudspeakers using moving-coil driver elements. A brief history of the industry is given, including a collection of products and patents from 1925 until the present, an overview of research papers, and a discussion of current products available. The mechanics of bending flat panels are developed with respect to localized driving forces, both in the frequency domain and the time domain as an impulse response. These simulations are compared to measurements on prototype panels. Additional resonant elements influence the behavior of the system: an optional ported rear enclosure and the resonant characteristics of the drivers. The governing equations for these systems are derived and solutions are implemented using equivalent mechanical circuits and numerical methods. The idea of using driver arrays to independently actuate modes of the panel is discussed at length with respect to modal addressability, modal spillover, and experimental validation. The numerical approach to determining the optimal driver placement for a given set of modes is derived and experimentally validated. An investigation of the acoustic behavior of flat panel loudspeakers is presented, using mechanical simulation results to predict the acoustic radiation. The simulations are compared to measurements and found to accurately predict important mechanical and acoustical behaviors. It is demonstrated that a driver array, with the proper biasing, is capable of creating a flat panel loudspeaker which acts more like a piston than a "diffuse radiator" flat panel loudspeaker. The techniques of "Modal Crossover Networks" are introduced, which use multi-band filters to bias the driver array differently for different frequency bands, optimized for audio reproduction. The question of how many drivers are necessary for a modal crossover network is addressed and found to be dependent on the estimated quality factor (Q) of the panel material and edge

Installed Base Registration of Decentralised Solar Panels with Applications in Crisis Management

NASA Astrophysics Data System (ADS)

Aarsen, R.; Janssen, M.; Ramkisoen, M.; Biljecki, F.; Quak, W.; Verbree, E.

2015-08-01

In case of a calamity in the Netherlands - e.g. a dike breach - parts of the nationwide electric network can fall out. In these occasions it would be useful if decentralised energy sources of the Smart Grid would contribute to balance out the fluctuations of the energy network. Decentralised energy sources include: solar energy, wind energy, combined heat and power, and biogas. In this manner, parts of the built environment - e.g. hospitals - that are in need of a continuous power flow, could be secured of this power. When a calamity happens, information about the Smart Grid is necessary to control the crisis and to ensure a shared view on the energy networks for both the crisis managers and network operators. The current situation of publishing, storing and sharing data of solar energy has been shown a lack of reliability about the current number, physical location, and capacity of installed decentralised photovoltaic (PV) panels in the Netherlands. This study focuses on decentralised solar energy in the form of electricity via PV panels in the Netherlands and addresses this challenge by proposing a new, reliable and up-to-date database. The study reveals the requirements for a registration of the installed base of PV panels in the Netherlands. This new database should serve as a replenishment for the current national voluntary registration, called Production Installation Register of Energy Data Services Netherland (EDSN-PIR), of installed decentralised PV panel installations in the Smart Grid, and provide important information in case of a calamity.

Development of a polymer based fiberoptic magnetostrictive metal detector system.

PubMed

Hua, Wei Shu; Hooks, Joshua Rosenberg; Wu, Wen Jong; Wang, Wei Chih

2010-10-01

This paper presents a new metal detector using a fiberoptic magnetostriction sensor. The metal sensor uses a fiber-optic Mach-Zehnder interferometer with a newly developed ferromagnetic polymer as the magnetostrictive sensing material. This polymeric magnetostrictive fiberoptic metal sensor is simple to fabricate, small in size, and resistant to RF interference (which is common in typical electromagnetic type metal detectors). Metal detection is based on disruption of the magnetic flux density across the magnetostriction sensor. In this paper, characteristics of the material being sensed and magnetic properties of the ferromagnetic polymers will be discussed.

Iodine 125 Imaging in Mice Using NaI(Tl)/Flat Panel PMT Integral Assembly

NASA Astrophysics Data System (ADS)

Cinti, M. N.; Majewski, S.; Williams, M. B.; Bachmann, C.; Cominelli, F.; Kundu, B. K.; Stolin, A.; Popov, V.; Welch, B. L.; De Vincentis, G.; Bennati, P.; Betti, M.; Ridolfi, S.; Pani, R.

2007-06-01

Radiolabeled agents that bind to specific receptors have shown great promise in diagnosing and characterizing tumor cell biology. In vivo imaging of gene transcription and protein expression represents an other area of interest. The radioisotope I is commercially available as a label for molecular probes and utilized by researchers in small animal studies. We propose an advanced imaging detector based on planar NaI(T1) integral assembly with a Hamamatsu Flat Panel Photomultiplier (MA-PMT) representing one of the best trade-offs between spatial resolution and detection efficiency. We characterized the imaging performances of this planar detector, in comparison with a gamma camera based on a pixellated scintillator. We also tested the in-vivo image capability by acquiring images of mice as a part of a study of inflammatory bowel disease (IBD). In this study, four 25g mice with an IBD-like phenotype (SAMP1/YitFc) were injected with 375, 125, 60 and 30 muCi of I-labelled antibody against mucosal vascular addressin cell adhesion molecule (MAdCAM-1), which is up-regulated in the presence of inflammation. Two mice without bowel inflammation were injected with 150 and 60 muCi of the labeled anti-MAdCAM-1 antibody as controls. To better evaluate the performances of the integral assembly detector, we also acquired mice images with a dual modality (X and Gamma Ray) camera dedicated for small animal imaging. The results coming from this new detector are considerable: images of SAMP1/YitFc injected with 30 muCi activity show inflammation throughout the intestinal tract, with the disease very well defined at two hours post-injection.

A MAPS Based Micro-Vertex Detector for the STAR Experiment

DOE PAGES

Schambach, Joachim; Anderssen, Eric; Contin, Giacomo; ...

2015-06-18

For the 2014 heavy ion run of RHIC a new micro-vertex detector called the Heavy Flavor Tracker (HFT) was installed in the STAR experiment. The HFT consists of three detector subsystems with various silicon technologies arranged in 4 approximately concentric cylinders close to the STAR interaction point designed to improve the STAR detector’s vertex resolution and extend its measurement capabilities in the heavy flavor domain. The two innermost HFT layers are placed at radii of 2.8 cm and 8 cm from the beam line. These layers are constructed with 400 high resolution sensors based on CMOS Monolithic Active Pixel Sensormore » (MAPS) technology arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors to cover a total silicon area of 0.16 m 2. Each sensor of this PiXeL (“PXL”) sub-detector combines a pixel array of 928 rows and 960 columns with a 20.7 μm pixel pitch together with front-end electronics and zero-suppression circuitry in one silicon die providing a sensitive area of ~3.8 cm 2. This sensor architecture features 185.6 μs readout time and 170 mW/cm 2 power dissipation. This low power dissipation allows the PXL detector to be air-cooled, and with the sensors thinned down to 50 μm results in a global material budget of only 0.4% radiation length per layer. A novel mechanical approach to detector insertion allows us to effectively install and integrate the PXL sub-detector within a 12 hour period during an on-going multi-month data taking period. The detector requirements, architecture and design, as well as the performance after installation, are presented in this paper.« less

Shear-Panel Test Fixture Eliminates Corner Stresses

NASA Technical Reports Server (NTRS)

Kiss, J. J.; Farley, G. L.; Baker, D. J.

1984-01-01

New design eliminates corner stresses while maintaining uniform stress across panel. Shear panel test fixture includes eight frames and eight corner pins. Fixture assembled in two halves with shear panel sandwiched in between. Results generated from this fixture will result in good data base for design of efficient aircraft structures and other applications.

A beam monitor based on MPGD detectors for hadron therapy

NASA Astrophysics Data System (ADS)

Altieri, P. R.; Di Benedetto, D.; Galetta, G.; Intonti, R. A.; Mercadante, A.; Nuzzo, S.; Verwilligen, P.

2018-02-01

Remarkable scientific and technological progress during the last years has led to the construction of accelerator based facilities dedicated to hadron therapy. This kind of technology requires precise and continuous control of position, intensity and shape of the ions or protons used to irradiate cancers. Patient safety, accelerator operation and dose delivery should be optimized by a real time monitoring of beam intensity and profile during the treatment, by using non-destructive, high spatial resolution detectors. In the framework of AMIDERHA (AMIDERHA - Enhanced Radiotherapy with HAdron) project funded by the Ministero dell'Istruzione, dell'Università e della Ricerca (Italian Ministry of Education and Research) the authors are studying and developing an innovative beam monitor based on Micro Pattern Gaseous Detectors (MPDGs) characterized by a high spatial resolution and rate capability. The Monte Carlo simulation of the beam monitor prototype was carried out to optimize the geometrical set up and to predict the behavior of the detector. A first prototype has been constructed and successfully tested using 55Fe, 90Sr and also an X-ray tube. Preliminary results on both simulations and tests will be presented.

Studies of materials for future ground-based and space-based interferometric gravitational wave detectors

NASA Astrophysics Data System (ADS)

Reid, Stuart

Studies of materials for future ground-based and space-based interferometric gravitational wave detectors. In 1916 Einstein predicted the existence of gravitational waves as a consequence of his Theory of General Relativity. These can be considered as fluctuations in the curvature, or ripples, in space-time. Until now there has only been indirect evidence for their existence. However, many scientists around the world over many years have been developing ultra-sensitive measurement techniques that are expected to be capable of detecting these signals, with the hope of providing new information on the astrophysical processes and sources that produce them. Gravitational waves are quadrupolar in nature and therefore produce orthogonal stretching and squeezing (i.e. a strain) of space. These fluctuations in distance are very small with astrophysical events predicted to produce strains at the earth of the order of 10-22 in the audio frequency band. One method for detecting such a strain is based on a Michelson Interferometer. The Institute for Gravitational Research in the University of Glasgow, under the leadership of Prof. J. Hough and has been actively involved in the research targeted towards the detection of gravitational waves for around 35 years. A strong collaboration exists with the Albert Einstein Institute in Hanover and Golm, the University of Hanover and the University of Cardiff. This collaboration has built an interferometer with 600 m arms in Germany called GEO600. GEO600 is designed to operate in a range of 50 Hz to a few kHz, with strain sensitivities reaching the order of 10-22/√Hz in the range 50 Hz → a few kHz. The work within this thesis describes various experiments carried out on materials and techniques used in current detectors and for the proposed future detectors. The principal aim is to cover various methods for reducing the levels of mechanical loss associated with the detector's optics and thereby minimising the impact of thermal noise

Silicon Drift Detectors - A Novel Technology for Vertex Detectors

NASA Astrophysics Data System (ADS)

Lynn, D.

1996-10-01

Silicon Drift Detectors (SDD) are novel position sensing silicon detectors which operate in a manner analogous to gas drift detectors. Single SDD's were shown in the CERN NA45 experiment to permit excellent spatial resolution (< 10 μm), to handle large particle occupancy, and to require a small fraction of the number of electronic channels of an equivalent pixel detector. The Silicon Vertex Tracker (SVT) for the STAR experiment at RHIC is based on this new technology. The SVT will consist of 216 SDD's, each 6.3 cm by 6.3 cm, arranged in a three layer barrel design, covering 2 π in azimuth and ±1 in pseudo-rapidity. Over the last three years we undertook a concentrated R+D effort to optimize the performance of the detector by minimizing the inactive area, the operating voltage and the data volume. We will present test results from several wafer prototypes. The charge produced by the passage of ionizing particles through the bulk of the detectors is collected on segmented anodes, with a pitch of 250 μm, on the far edges of the detector. The anodes are wire-bonded to a thick film multi-chip module which contains preamplifier/shaper chips and CMOS based switched capacitor arrays used as an analog memory pipeline. The ADC is located off-detector. The complete readout chain from the wafer to the DAQ will be presented. Finally we will show physics performance simulations based on the resolution achieved by the SVT prototypes.

Panel cutting method: new approach to generate panels on a hull in Rankine source potential approximation

NASA Astrophysics Data System (ADS)

Choi, Hee-Jong; Chun, Ho-Hwan; Park, Il-Ryong; Kim, Jin

2011-12-01

In the present study, a new hull panel generation algorithm, namely panel cutting method, was developed to predict flow phenomena around a ship using the Rankine source potential based panel method, where the iterative method was used to satisfy the nonlinear free surface condition and the trim and sinkage of the ship was taken into account. Numerical computations were performed to investigate the validity of the proposed hull panel generation algorithm for Series 60 (CB=0.60) hull and KRISO container ship (KCS), a container ship designed by Maritime and Ocean Engineering Research Institute (MOERI). The computational results were validated by comparing with the existing experimental data.

Numerical Investigation on Electron and Ion Transmission of GEM-based Detectors

NASA Astrophysics Data System (ADS)

Bhattacharya, Purba; Sahoo, Sumanya Sekhar; Biswas, Saikat; Mohanty, Bedangadas; Majumdar, Nayana; Mukhopadhyay, Supratik

2018-02-01

ALICE at the LHC is planning a major upgrade of its detector systems, including the TPC, to cope with an increase of the LHC luminosity after 2018. Different R&D activities are currently concentrated on the adoption of the Gas Electron Multiplier (GEM) as the gas amplification stage of the ALICE-TPC upgrade version. The major challenge is to have low ion feedback in the drift volume as well as to ensure a collection of good percentage of primary electrons in the signal generation process. In the present work, Garfield simulation framework has been adopted to numerically estimate the electron transparency and ion backflow fraction of GEM-based detectors. In this process, extensive simulations have been carried out to enrich our understanding of the complex physical processes occurring within single, triple and quadruple GEM detectors. A detailed study has been performed to observe the effect of detector geometry, field configuration and magnetic field on the above mentioned characteristics.

Outbrief - Long Life Rocket Engine Panel

NASA Technical Reports Server (NTRS)

Quinn, Jason Eugene

2004-01-01

This white paper is an overview of the JANNAF Long Life Rocket Engine (LLRE) Panel results from the last several years of activity. The LLRE Panel has met over the last several years in order to develop an approach for the development of long life rocket engines. Membership for this panel was drawn from a diverse set of the groups currently working on rocket engines (Le. government labs, both large and small companies and university members). The LLRE Panel was formed in order to determine the best way to enable the design of rocket engine systems that have life capability greater than 500 cycles while meeting or exceeding current performance levels (Specific Impulse and Thrust/Weight) with a 1/1,OOO,OOO likelihood of vehicle loss due to rocket system failure. After several meetings and much independent work the panel reached a consensus opinion that the primary issues preventing LLRE are a lack of: physics based life prediction, combined loads prediction, understanding of material microphysics, cost effective system level testing. and the inclusion of fabrication process effects into physics based models. With the expected level of funding devoted to LLRE development, the panel recommended that fundamental research efforts focused on these five areas be emphasized.

SU-E-I-07: Response Characteristics and Signal Conversion Modeling of KV Flat-Panel Detector in Cone Beam CT System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yu; Cao, Ruifen; Pei, Xi

2015-06-15

Purpose: The flat-panel detector response characteristics are investigated to optimize the scanning parameter considering the image quality and less radiation dose. The signal conversion model is also established to predict the tumor shape and physical thickness changes. Methods: With the ELEKTA XVI system, the planar images of 10cm water phantom were obtained under different image acquisition conditions, including tube voltage, electric current, exposure time and frames. The averaged responses of square area in center were analyzed using Origin8.0. The response characteristics for each scanning parameter were depicted by different fitting types. The transmission measured for 10cm water was compared tomore » Monte Carlo simulation. Using the quadratic calibration method, a series of variable-thickness water phantoms images were acquired to derive the signal conversion model. A 20cm wedge water phantom with 2cm step thickness was used to verify the model. At last, the stability and reproducibility of the model were explored during a four week period. Results: The gray values of image center all decreased with the increase of different image acquisition parameter presets. The fitting types adopted were linear fitting, quadratic polynomial fitting, Gauss fitting and logarithmic fitting with the fitting R-Square 0.992, 0.995, 0.997 and 0.996 respectively. For 10cm water phantom, the transmission measured showed better uniformity than Monte Carlo simulation. The wedge phantom experiment show that the radiological thickness changes prediction error was in the range of (-4mm, 5mm). The signal conversion model remained consistent over a period of four weeks. Conclusion: The flat-panel response decrease with the increase of different scanning parameters. The preferred scanning parameter combination was 100kV, 10mA, 10ms, 15frames. It is suggested that the signal conversion model could effectively be used for tumor shape change and radiological thickness prediction

Integrated analysis on static/dynamic aeroelasticity of curved panels based on a modified local piston theory

NASA Astrophysics Data System (ADS)

Yang, Zhichun; Zhou, Jian; Gu, Yingsong

2014-10-01

A flow field modified local piston theory, which is applied to the integrated analysis on static/dynamic aeroelastic behaviors of curved panels, is proposed in this paper. The local flow field parameters used in the modification are obtained by CFD technique which has the advantage to simulate the steady flow field accurately. This flow field modified local piston theory for aerodynamic loading is applied to the analysis of static aeroelastic deformation and flutter stabilities of curved panels in hypersonic flow. In addition, comparisons are made between results obtained by using the present method and curvature modified method. It shows that when the curvature of the curved panel is relatively small, the static aeroelastic deformations and flutter stability boundaries obtained by these two methods have little difference, while for curved panels with larger curvatures, the static aeroelastic deformation obtained by the present method is larger and the flutter stability boundary is smaller compared with those obtained by the curvature modified method, and the discrepancy increases with the increasing of curvature of panels. Therefore, the existing curvature modified method is non-conservative compared to the proposed flow field modified method based on the consideration of hypersonic flight vehicle safety, and the proposed flow field modified local piston theory for curved panels enlarges the application range of piston theory.

Accuracy of flat panel detector CT with integrated navigational software with and without MR fusion for single-pass needle placement.

PubMed

Mabray, Marc C; Datta, Sanjit; Lillaney, Prasheel V; Moore, Teri; Gehrisch, Sonja; Talbott, Jason F; Levitt, Michael R; Ghodke, Basavaraj V; Larson, Paul S; Cooke, Daniel L

2016-07-01

Fluoroscopic systems in modern interventional suites have the ability to perform flat panel detector CT (FDCT) with navigational guidance. Fusion with MR allows navigational guidance towards FDCT occult targets. We aim to evaluate the accuracy of this system using single-pass needle placement in a deep brain stimulation (DBS) phantom. MR was performed on a head phantom with DBS lead targets. The head phantom was placed into fixation and FDCT was performed. FDCT and MR datasets were automatically fused using the integrated guidance system (iGuide, Siemens). A DBS target was selected on the MR dataset. A 10 cm, 19 G needle was advanced by hand in a single pass using laser crosshair guidance. Radial error was visually assessed against measurement markers on the target and by a second FDCT. Ten needles were placed using CT-MR fusion and 10 needles were placed without MR fusion, with targeting based solely on FDCT and fusion steps repeated for every pass. Mean radial error was 2.75±1.39 mm as defined by visual assessment to the centre of the DBS target and 2.80±1.43 mm as defined by FDCT to the centre of the selected target point. There were no statistically significant differences in error between MR fusion and non-MR guided series. Single pass needle placement in a DBS phantom using FDCT guidance is associated with a radial error of approximately 2.5-3.0 mm at a depth of approximately 80 mm. This system could accurately target sub-centimetre intracranial lesions defined on MR. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Evolution in boron-based GEM detectors for diffraction measurements: from planar to 3D converters

NASA Astrophysics Data System (ADS)

Albani, Giorgia; Perelli Cippo, Enrico; Croci, Gabriele; Muraro, Andrea; Schooneveld, Erik; Scherillo, Antonella; Hall-Wilton, Richard; Kanaki, Kalliopi; Höglund, Carina; Hultman, Lars; Birch, Jens; Claps, Gerardo; Murtas, Fabrizio; Rebai, Marica; Tardocchi, Marco; Gorini, Giuseppe

2016-11-01

The so-called ‘3He-crisis’ has motivated the neutron detector community to undertake an intense R&D programme in order to develop technologies alternative to standard 3He tubes and suitable for neutron detection systems in future spallation sources such as the European spallation source (ESS). Boron-based GEM (gas electron multiplier) detectors are a promising ‘3He-free’ technology for thermal neutron detection in neutron scattering experiments. In this paper the evolution of boron-based GEM detectors from planar to 3D converters with an application in diffraction measurements is presented. The use of 3D converters coupled with GEMs allows for an optimization of the detector performances. Three different detectors were used for diffraction measurements on the INES instrument at the ISIS spallation source. The performances of the GEM-detectors are compared with those of conventional 3He tubes installed on the INES instrument. The conceptual detector with the 3D converter used in this paper reached a count rate per unit area of about 25% relative to the currently installed 3He tube. Its timing resolution is similar and the signal-to-background ratio (S/B) is 2 times lower.

Position sensitive and energy dispersive x-ray detector based on silicon strip detector technology

NASA Astrophysics Data System (ADS)

Wiącek, P.; Dąbrowski, W.; Fink, J.; Fiutowski, T.; Krane, H.-G.; Loyer, F.; Schwamberger, A.; Świentek, K.; Venanzi, C.

2015-04-01

A new position sensitive detector with a global energy resolution for the entire detector of about 380 eV FWHM for 8.04 keV line at ambient temperature is presented. The measured global energy resolution is defined by the energy spectra summed over all strips of the detector, and thus it includes electronic noise of the front-end electronics, charge sharing effects, matching of parameters across the channels and other system noise sources. The target energy resolution has been achieved by segmentation of the strips to reduce their capacitance and by careful optimization of the front-end electronics. The key design aspects and parameters of the detector are discussed briefly in the paper. Excellent noise and matching performance of the readout ASIC and negligible system noise allow us to operate the detector with a discrimination threshold as low as 1 keV and to measure fluorescence radiation lines of light elements, down to Al Kα of 1.49 keV, simultaneously with measurements of the diffraction patterns. The measurement results that demonstrate the spectrometric and count rate performance of the developed detector are presented and discussed in the paper.

A Compton suppressed detector multiplicity trigger based digital DAQ for gamma-ray spectroscopy

NASA Astrophysics Data System (ADS)

Das, S.; Samanta, S.; Banik, R.; Bhattacharjee, R.; Basu, K.; Raut, R.; Ghugre, S. S.; Sinha, A. K.; Bhattacharya, S.; Imran, S.; Mukherjee, G.; Bhattacharyya, S.; Goswami, A.; Palit, R.; Tan, H.

2018-06-01

The development of a digitizer based pulse processing and data acquisition system for γ-ray spectroscopy with large detector arrays is presented. The system is based on 250 MHz 12-bit digitizers, and is triggered by a user chosen multiplicity of Compton suppressed detectors. The logic for trigger generation is similar to the one practised for analog (NIM/CAMAC) pulse processing electronics, while retaining the fast processing merits of the digitizer system. Codes for reduction of data acquired from the system have also been developed. The system has been tested with offline studies using radioactive sources as well as in the in-beam experiments with an array of Compton suppressed Clover detectors. The results obtained therefrom validate its use in spectroscopic efforts for nuclear structure investigations.

Graphene-Based Josephson-Junction Single-Photon Detector

NASA Astrophysics Data System (ADS)

Walsh, Evan D.; Efetov, Dmitri K.; Lee, Gil-Ho; Heuck, Mikkel; Crossno, Jesse; Ohki, Thomas A.; Kim, Philip; Englund, Dirk; Fong, Kin Chung

2017-08-01

We propose to use graphene-based Josephson junctions (GJJs) to detect single photons in a wide electromagnetic spectrum from visible to radio frequencies. Our approach takes advantage of the exceptionally low electronic heat capacity of monolayer graphene and its constricted thermal conductance to its phonon degrees of freedom. Such a system could provide high-sensitivity photon detection required for research areas including quantum information processing and radio astronomy. As an example, we present our device concepts for GJJ single-photon detectors in both the microwave and infrared regimes. The dark count rate and intrinsic quantum efficiency are computed based on parameters from a measured GJJ, demonstrating feasibility within existing technologies.

Heat exchanger panel

NASA Technical Reports Server (NTRS)

Warburton, Robert E. (Inventor); Cuva, William J. (Inventor)

2005-01-01

The present invention relates to a heat exchanger panel which has broad utility in high temperature environments. The heat exchanger panel has a first panel, a second panel, and at least one fluid containment device positioned intermediate the first and second panels. At least one of the first panel and the second panel have at least one feature on an interior surface to accommodate the at least one fluid containment device. In a preferred embodiment, each of the first and second panels is formed from a high conductivity, high temperature composite material. Also, in a preferred embodiment, the first and second panels are joined together by one or more composite fasteners.

A Photoactivated Gas Detector for Toluene Sensing at Room Temperature Based on New Coral-Like ZnO Nanostructure Arrays.

PubMed

Yeh, Li-Ko; Luo, Jie-Chun; Chen, Min-Chun; Wu, Chih-Hung; Chen, Jian-Zhang; Cheng, I-Chun; Hsu, Cheng-Che; Tian, Wei-Cheng

2016-10-31

A photoactivated gas detector operated at room temperature was microfabricated using a simple hydrothermal method. We report that the photoactivated gas detector can detect toluene using a UV illumination of 2 μW/cm². By ultraviolet (UV) illumination, gas detectors sense toluene at room temperature without heating. A significant enhancement of detector sensitivity is achieved because of the high surface-area-to-volume ratio of the morphology of the coral-like ZnO nanorods arrays (NRAs) and the increased number of photo-induced oxygen ions under UV illumination. The corresponding sensitivity (ΔR/R₀) of the detector based on coral-like ZnO NRAs is enhanced by approximately 1022% compared to that of thin-film detectors. The proposed detector greatly extends the dynamic range of detection of metal-oxide-based detectors for gas sensing applications. We report the first-ever detection of toluene with a novel coral-like NRAs gas detector at room temperature. A sensing mechanism model is also proposed to explain the sensing responses of gas detectors based on coral-like ZnO NRAs.

A Photoactivated Gas Detector for Toluene Sensing at Room Temperature Based on New Coral-Like ZnO Nanostructure Arrays

PubMed Central

Yeh, Li-Ko; Luo, Jie-Chun; Chen, Min-Chun; Wu, Chih-Hung; Chen, Jian-Zhang; Cheng, I-Chun; Hsu, Cheng-Che; Tian, Wei-Cheng

2016-01-01

A photoactivated gas detector operated at room temperature was microfabricated using a simple hydrothermal method. We report that the photoactivated gas detector can detect toluene using a UV illumination of 2 μW/cm2. By ultraviolet (UV) illumination, gas detectors sense toluene at room temperature without heating. A significant enhancement of detector sensitivity is achieved because of the high surface-area-to-volume ratio of the morphology of the coral-like ZnO nanorods arrays (NRAs) and the increased number of photo-induced oxygen ions under UV illumination. The corresponding sensitivity (ΔR/R0) of the detector based on coral-like ZnO NRAs is enhanced by approximately 1022% compared to that of thin-film detectors. The proposed detector greatly extends the dynamic range of detection of metal-oxide-based detectors for gas sensing applications. We report the first-ever detection of toluene with a novel coral-like NRAs gas detector at room temperature. A sensing mechanism model is also proposed to explain the sensing responses of gas detectors based on coral-like ZnO NRAs. PMID:27809222

An ergonomics based design research method for the arrangement of helicopter flight instrument panels.

PubMed

Alppay, Cem; Bayazit, Nigan

2015-11-01

In this paper, we study the arrangement of displays in flight instrument panels of multi-purpose civil helicopters following a user-centered design method based on ergonomics principles. Our methodology can also be described as a user-interface arrangement methodology based on user opinions and preferences. This study can be outlined as gathering user-centered data using two different research methods and then analyzing and integrating the collected data to come up with an optimal instrument panel design. An interview with helicopter pilots formed the first step of our research. In that interview, pilots were asked to provide a quantitative evaluation of basic interface arrangement principles. In the second phase of the research, a paper prototyping study was conducted with same pilots. The final phase of the study entailed synthesizing the findings from interviews and observational studies to formulate an optimal flight instrument arrangement methodology. The primary results that we present in our paper are the methodology that we developed and three new interface arrangement concepts, namely relationship of inseparability, integrated value and locational value. An optimum instrument panel arrangement is also proposed by the researchers. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Volumetric soft tissue brain imaging on xCAT, a mobile flat-panel x-ray CT system

NASA Astrophysics Data System (ADS)

Zbijewski, Wojciech; Stayman, J. Webster

2009-02-01

We discuss the ongoing development of soft-tissue imaging capabilities on xCAT, a highly portable, flat-panel based cone-beam X-ray CT platform. By providing the ability to rapidly detect intra-cranial bleeds and other symptoms of stroke directly at the patient's bedside, our new system can potentially significantly improve the management of neurological emergency and intensive care patients. The paper reports on the design of our system, as well as on the methods used to combat artifacts due to scatter, non-linear detector response and scintillator glare. Images of cadaveric head samples are also presented and compared with conventional CT scans.

Nonlinear flutter analysis of composite panels

NASA Astrophysics Data System (ADS)

An, Xiaomin; Wang, Yan

2018-05-01

Nonlinear panel flutter is an interesting subject of fluid-structure interaction. In this paper, nonlinear flutter characteristics of curved composite panels are studied in very low supersonic flow. The composite panel with geometric nonlinearity is modeled by a nonlinear finite element method; and the responses are computed by the nonlinear Newmark algorithm. An unsteady aerodynamic solver, which contains a flux splitting scheme and dual time marching technology, is employed in calculating the unsteady pressure of the motion of the panel. Based on a half-step staggered coupled solution, the aeroelastic responses of two composite panels with different radius of R = 5 and R = 2.5 are computed and compared with each other at different dynamic pressure for Ma = 1.05. The nonlinear flutter characteristics comprising limited cycle oscillations and chaos are analyzed and discussed.

Position detectors, methods of detecting position, and methods of providing positional detectors

DOEpatents

Weinberg, David M.; Harding, L. Dean; Larsen, Eric D.

2002-01-01

Position detectors, welding system position detectors, methods of detecting various positions, and methods of providing position detectors are described. In one embodiment, a welding system positional detector includes a base that is configured to engage and be moved along a curved surface of a welding work piece. At least one position detection apparatus is provided and is connected with the base and configured to measure angular position of the detector relative to a reference vector. In another embodiment, a welding system positional detector includes a weld head and at least one inclinometer mounted on the weld head. The one inclinometer is configured to develop positional data relative to a reference vector and the position of the weld head on a non-planar weldable work piece.

Region-of-interest cone beam computed tomography (ROI CBCT) with a high resolution CMOS detector.

PubMed

Jain, A; Takemoto, H; Silver, M D; Nagesh, S V S; Ionita, C N; Bednarek, D R; Rudin, S

Cone beam computed tomography (CBCT) systems with rotational gantries that have standard flat panel detectors (FPD) are widely used for the 3D rendering of vascular structures using Feldkamp cone beam reconstruction algorithms. One of the inherent limitations of these systems is limited resolution (<3 lp/mm). There are systems available with higher resolution but their small FOV limits them to small animal imaging only. In this work, we report on region-of-interest (ROI) CBCT with a high resolution CMOS detector (75 μm pixels, 600 μm HR-CsI) mounted with motorized detector changer on a commercial FPD-based C-arm angiography gantry (194 μm pixels, 600 μm HL-CsI). A cylindrical CT phantom and neuro stents were imaged with both detectors. For each detector a total of 209 images were acquired in a rotational protocol. The technique parameters chosen for the FPD by the imaging system were used for the CMOS detector. The anti-scatter grid was removed and the incident scatter was kept the same for both detectors with identical collimator settings. The FPD images were reconstructed for the 10 cm x10 cm FOV and the CMOS images were reconstructed for a 3.84 cm × 3.84 cm FOV. Although the reconstructed images from the CMOS detector demonstrated comparable contrast to the FPD images, the reconstructed 3D images of the neuro stent clearly showed that the CMOS detector improved delineation of smaller objects such as the stent struts (~70 μm) compared to the FPD. Further development and the potential for substantial clinical impact are suggested.

Wood-based panel plant locations and timber availability in selected U.S. states

Treesearch

T. McKeever; H. N. Spelter

1998-01-01

This report lists wood-based panel industry plant locations, production capacities, timber inventories, and wood costs for 24 U.S. states. Industry sectors covered include medium-density fiberboard, particleboard, softwood plywood, and oriented strandboard. Maps of major forest producing states show plant locations and the underlying density of timber stocking by...

AIGO: a southern hemisphere detector for the worldwide array of ground-based interferometric gravitational wave detectors

NASA Astrophysics Data System (ADS)

Barriga, P.; Blair, D. G.; Coward, D.; Davidson, J.; Dumas, J.-C.; Howell, E.; Ju, L.; Wen, L.; Zhao, C.; McClelland, D. E.; Scott, S. M.; Slagmolen, B. J. J.; Inta, R.; Munch, J.; Ottaway, D. J.; Veitch, P.; Hosken, D.; Melatos, A.; Chung, C.; Sammut, L.; Galloway, D. K.; Marx, J.; Whitcomb, S.; Shoemaker, D.; Hughes, S. A.; Reitze, D. H.; Iyer, B. R.; Dhurandhar, S. V.; Souradeep, T.; Unnikrishnan, C. S.; Rajalakshmi, G.; Man, C. N.; Heidmann, A.; Cohadon, P.-F.; Briant, T.; Grote, H.; Danzmann, K.; Lück, H.; Willke, B.; Strain, K. A.; Sathyaprakash, B. S.; Cao, J.; Cheung, Y.-K. E.; Zhang, Y.

2010-04-01

This paper describes the proposed AIGO detector for the worldwide array of interferometric gravitational wave detectors. The first part of the paper summarizes the benefits that AIGO provides to the worldwide array of detectors. The second part gives a technical description of the detector, which will follow closely the Advanced LIGO design. Possible technical variations in the design are discussed.

Improved imputation accuracy of rare and low-frequency variants using population-specific high-coverage WGS-based imputation reference panel.

PubMed

Mitt, Mario; Kals, Mart; Pärn, Kalle; Gabriel, Stacey B; Lander, Eric S; Palotie, Aarno; Ripatti, Samuli; Morris, Andrew P; Metspalu, Andres; Esko, Tõnu; Mägi, Reedik; Palta, Priit

2017-06-01

Genetic imputation is a cost-efficient way to improve the power and resolution of genome-wide association (GWA) studies. Current publicly accessible imputation reference panels accurately predict genotypes for common variants with minor allele frequency (MAF)≥5% and low-frequency variants (0.5≤MAF<5%) across diverse populations, but the imputation of rare variation (MAF<0.5%) is still rather limited. In the current study, we evaluate imputation accuracy achieved with reference panels from diverse populations with a population-specific high-coverage (30 ×) whole-genome sequencing (WGS) based reference panel, comprising of 2244 Estonian individuals (0.25% of adult Estonians). Although the Estonian-specific panel contains fewer haplotypes and variants, the imputation confidence and accuracy of imputed low-frequency and rare variants was significantly higher. The results indicate the utility of population-specific reference panels for human genetic studies.

Thin film CdTe based neutron detectors with high thermal neutron efficiency and gamma rejection for security applications

NASA Astrophysics Data System (ADS)

Smith, L.; Murphy, J. W.; Kim, J.; Rozhdestvenskyy, S.; Mejia, I.; Park, H.; Allee, D. R.; Quevedo-Lopez, M.; Gnade, B.

2016-12-01

Solid-state neutron detectors offer an alternative to 3He based detectors, but suffer from limited neutron efficiencies that make their use in security applications impractical. Solid-state neutron detectors based on single crystal silicon also have relatively high gamma-ray efficiencies that lead to false positives. Thin film polycrystalline CdTe based detectors require less complex processing with significantly lower gamma-ray efficiencies. Advanced geometries can also be implemented to achieve high thermal neutron efficiencies competitive with silicon based technology. This study evaluates these strategies by simulation and experimentation and demonstrates an approach to achieve >10% intrinsic efficiency with <10-6 gamma-ray efficiency.

Smile detectors correlation

NASA Astrophysics Data System (ADS)

Yuksel, Kivanc; Chang, Xin; Skarbek, Władysław

2017-08-01

The novel smile recognition algorithm is presented based on extraction of 68 facial salient points (fp68) using the ensemble of regression trees. The smile detector exploits the Support Vector Machine linear model. It is trained with few hundreds exemplar images by SVM algorithm working in 136 dimensional space. It is shown by the strict statistical data analysis that such geometric detector strongly depends on the geometry of mouth opening area, measured by triangulation of outer lip contour. To this goal two Bayesian detectors were developed and compared with SVM detector. The first uses the mouth area in 2D image, while the second refers to the mouth area in 3D animated face model. The 3D modeling is based on Candide-3 model and it is performed in real time along with three smile detectors and statistics estimators. The mouth area/Bayesian detectors exhibit high correlation with fp68/SVM detector in a range [0:8; 1:0], depending mainly on light conditions and individual features with advantage of 3D technique, especially in hard light conditions.

Development and characterization of high-resolution neutron pixel detectors based on Timepix read-out chips

NASA Astrophysics Data System (ADS)

Krejci, F.; Zemlicka, J.; Jakubek, J.; Dudak, J.; Vavrik, D.; Köster, U.; Atkins, D.; Kaestner, A.; Soltes, J.; Viererbl, L.; Vacik, J.; Tomandl, I.

2016-12-01

Using a suitable isotope such as 6Li and 10B semiconductor hybrid pixel detectors can be successfully adapted for position sensitive detection of thermal and cold neutrons via conversion into energetic light ions. The adapted devices then typically provides spatial resolution at the level comparable to the pixel pitch (55 μm) and sensitive area of about few cm2. In this contribution, we describe further progress in neutron imaging performance based on the development of a large-area hybrid pixel detector providing practically continuous neutron sensitive area of 71 × 57 mm2. The measurements characterising the detector performance at the cold neutron imaging instrument ICON at PSI and high-flux imaging beam-line Neutrograph at ILL are presented. At both facilities, high-resolution high-contrast neutron radiography with the newly developed detector has been successfully applied for objects which imaging were previously difficult with hybrid pixel technology (such as various composite materials, objects of cultural heritage etc.). Further, a significant improvement in the spatial resolution of neutron radiography with hybrid semiconductor pixel detector based on the fast read-out Timepix-based detector is presented. The system is equipped with a thin planar 6LiF convertor operated effectively in the event-by-event mode enabling position sensitive detection with spatial resolution better than 10 μm.

35t Prototype Detector for Experiment at Long Base Line Neutrino Facility (ELBNF) Far Detector

NASA Astrophysics Data System (ADS)

Santucci, Gabriel; Elbnf Collaboration

2015-04-01

The 35ton prototype detector is a Liquid Argon Time Projection Chamber (LAr TPC) utilizing a membrane cryostat. It serves as a prototype for testing technology proposed for the ELBNF far detector. The construction of the prototype is an essential part of the ELBNF project due to the large amount of new technologies introduced for the far detector. In early 2014, it was shown that the membrane cryostat technology was able to reach and maintain the required LAr purity and an electron lifetime of 2.5 ms was achieved. The goals for the next phase include the installation of a fully functional TPC using the novel designs for the ELBNF far detector as much as possible. This includes the installation of the cold electronics, scintillation photon detectors and multiple Anode Plane Arrays with wrapped wires. In this talk I will review the status of the 35t prototype detector and describe what has been accomplished during 2014 and early 2015, including the commissioning phase and the early stages of data taking from cosmic-rays.

Novel detectors for silicon based microdosimetry, their concepts and applications

NASA Astrophysics Data System (ADS)

Rosenfeld, Anatoly B.

2016-02-01

This paper presents an overview of the development of semiconductor microdosimetry and the most current (state-of-the-art) Silicon on Insulator (SOI) detectors for microdosimetry based mainly on research and development carried out at the Centre for Medical Radiation Physics (CMRP) at the University of Wollongong with collaborators over the last 18 years. In this paper every generation of CMRP SOI microdosimeters, including their fabrication, design, and electrical and charge collection characterisation are presented. A study of SOI microdosimeters in various radiation fields has demonstrated that under appropriate geometrical scaling, the response of SOI detectors with the well-known geometry of microscopically sensitive volumes will record the energy deposition spectra representative of tissue cells of an equivalent shape. This development of SOI detectors for microdosimetry with increased complexity has improved the definition of microscopic sensitive volume (SV), which is modelling the deposition of ionising energy in a biological cell, that are led from planar to 3D SOI detectors with an array of segmented microscopic 3D SVs. The monolithic ΔE-E silicon telescope, which is an alternative to the SOI silicon microdosimeter, is presented, and as an example, applications of SOI detectors and ΔE-E monolithic telescope for microdosimetery in proton therapy field and equivalent neutron dose measurements out of field are also presented. An SOI microdosimeter "bridge" with 3D SVs can derive the relative biological effectiveness (RBE) in 12C ion radiation therapy that matches the tissue equivalent proportional counter (TEPC) quite well, but with outstanding spatial resolution. The use of SOI technology in experimental microdosimetry offers simplicity (no gas system or HV supply), high spatial resolution, low cost, high count rates, and the possibility of integrating the system onto a single device with other types of detectors.

The method of neutron imaging as a tool for the study of the dynamics of water movement in wet aramid-based ballistic body armour panels

NASA Astrophysics Data System (ADS)

Reifler, Felix A.; Lehmann, Eberhard H.; Frei, Gabriel; May, Hans; Rossi, René

2006-07-01

A new non-destructive method based on neutron imaging (neutron radiography) to determine the exact water content in aramid-based soft body armour panels is presented. While investigating the ballistic resistance of aramid-based body armour panels under a wet condition, it is important to precisely determine their water content and its chronological development. Using the presented method, the influence of water amount and location on impact testing as well as its time dependence was shown. In the ballistic panels used, spreading of water strongly depended on the kind of quilting. Very fast water migration could be observed when the panels were held vertically. Some first results regarding the water distribution in wet panels immediately after the impact are presented. On the basis of the presented results, requirements for a standard for testing the performance of ballistic panels in the wet state are deduced.

A Weak Value Based QKD Protocol Robust Against Detector Attacks

NASA Astrophysics Data System (ADS)

Troupe, James

2015-03-01

We propose a variation of the BB84 quantum key distribution protocol that utilizes the properties of weak values to insure the validity of the quantum bit error rate estimates used to detect an eavesdropper. The protocol is shown theoretically to be secure against recently demonstrated attacks utilizing detector blinding and control and should also be robust against all detector based hacking. Importantly, the new protocol promises to achieve this additional security without negatively impacting the secure key generation rate as compared to that originally promised by the standard BB84 scheme. Implementation of the weak measurements needed by the protocol should be very feasible using standard quantum optical techniques.

Optimization-based image reconstruction from sparse-view data in offset-detector CBCT

NASA Astrophysics Data System (ADS)

Bian, Junguo; Wang, Jiong; Han, Xiao; Sidky, Emil Y.; Shao, Lingxiong; Pan, Xiaochuan

2013-01-01

The field of view (FOV) of a cone-beam computed tomography (CBCT) unit in a single-photon emission computed tomography (SPECT)/CBCT system can be increased by offsetting the CBCT detector. Analytic-based algorithms have been developed for image reconstruction from data collected at a large number of densely sampled views in offset-detector CBCT. However, the radiation dose involved in a large number of projections can be of a health concern to the imaged subject. CBCT-imaging dose can be reduced by lowering the number of projections. As analytic-based algorithms are unlikely to reconstruct accurate images from sparse-view data, we investigate and characterize in the work optimization-based algorithms, including an adaptive steepest descent-weighted projection onto convex sets (ASD-WPOCS) algorithms, for image reconstruction from sparse-view data collected in offset-detector CBCT. Using simulated data and real data collected from a physical pelvis phantom and patient, we verify and characterize properties of the algorithms under study. Results of our study suggest that optimization-based algorithms such as ASD-WPOCS may be developed for yielding images of potential utility from a number of projections substantially smaller than those used currently in clinical SPECT/CBCT imaging, thus leading to a dose reduction in CBCT imaging.

Mini Compton Camera Based on an Array of Virtual Frisch-Grid CdZnTe Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Wonho; Bolotnikov, Aleksey; Lee, Taewoong

In this study, we constructed a mini Compton camera based on an array of CdZnTe detectors and assessed its spectral and imaging properties. The entire array consisted of 6×6 Frisch-grid CdZnTe detectors, each with a size of 6×6 ×15 mm 3. Since it is easier and more practical to grow small CdZnTe crystals rather than large monolithic ones, constructing a mosaic array of parallelepiped crystals can be an effective way to build a more efficient, large-volume detector. With the fully operational CdZnTe array, we measured the energy spectra for 133Ba -, 137Cs -, 60Co-radiation sources; we also located these sourcesmore » using a Compton imaging approach. Although the Compton camera was small enough to hand-carry, its intrinsic efficiency was several orders higher than those generated in previous researches using spatially separated arrays, because our camera measured the interactions inside the CZT detector array, wherein the detector elements were positioned very close to each other. Lastly, the performance of our camera was compared with that based on a pixelated detector.« less

Mini Compton Camera Based on an Array of Virtual Frisch-Grid CdZnTe Detectors

DOE PAGES

Lee, Wonho; Bolotnikov, Aleksey; Lee, Taewoong; ...

2016-02-15

In this study, we constructed a mini Compton camera based on an array of CdZnTe detectors and assessed its spectral and imaging properties. The entire array consisted of 6×6 Frisch-grid CdZnTe detectors, each with a size of 6×6 ×15 mm 3. Since it is easier and more practical to grow small CdZnTe crystals rather than large monolithic ones, constructing a mosaic array of parallelepiped crystals can be an effective way to build a more efficient, large-volume detector. With the fully operational CdZnTe array, we measured the energy spectra for 133Ba -, 137Cs -, 60Co-radiation sources; we also located these sourcesmore » using a Compton imaging approach. Although the Compton camera was small enough to hand-carry, its intrinsic efficiency was several orders higher than those generated in previous researches using spatially separated arrays, because our camera measured the interactions inside the CZT detector array, wherein the detector elements were positioned very close to each other. Lastly, the performance of our camera was compared with that based on a pixelated detector.« less

Panel to review EOSDIS plans

NASA Technical Reports Server (NTRS)

1994-01-01

baseline architecture that was not previously available, due to procurement restrictions. This report presents the panel's findings and recommendations based on this additional information.

Python based integration of GEM detector electronics with JET data acquisition system

NASA Astrophysics Data System (ADS)

Zabołotny, Wojciech M.; Byszuk, Adrian; Chernyshova, Maryna; Cieszewski, Radosław; Czarski, Tomasz; Dalley, Simon; Hogben, Colin; Jakubowska, Katarzyna L.; Kasprowicz, Grzegorz; Poźniak, Krzysztof; Rzadkiewicz, Jacek; Scholz, Marek; Shumack, Amy

2014-11-01

This paper presents the system integrating the dedicated measurement and control electronic systems for Gas Electron Multiplier (GEM) detectors with the Control and Data Acquisition system (CODAS) in the JET facility in Culham, England. The presented system performs the high level procedures necessary to calibrate the GEM detector and to protect it against possible malfunctions or dangerous changes in operating conditions. The system also allows control of the GEM detectors from CODAS, setting of their parameters, checking their state, starting the plasma measurement and to reading the results. The system has been implemented using the Python language, using the advanced libraries for implementation of network communication protocols, for object based hardware management and for data processing.

A dual-wavelength light-emitting diode based detector for flow-injection analysis process analysers.

PubMed

Huang, J; Liu, H; Tan, A; Xu, J; Zhao, X

1992-06-01

In this paper, a small dual-wavelength light-emitting diode (LED) based detector for FIA process analysers is designed. The detector's optical parts include a flow cell, a dual-wavelength LED and a photodiode. Neither mirrors nor lenses are used. The optical paths for the different light beams are almost the same, distinguishing it from previously reported LED based detectors. The detector's electronic components, including a signal amplifier, an A/D and D/A converter, and an Intel 8031 single-chip microcomputer, are integrated on one small board. In order to obtain response signals of approximate intensity for the two colours, the D/A converter and a multiplexer are used to adjust the emission intensity of the two colours respectively. Under microcomputer control, light beams are rapidly electronically modulated. Therefore, dark current and intensity of the light beams are measured almost simultaneously; as a result, the effect of drift is negligible. While a solution of absorbance 0.875 was measured repeatedly, an RSD (relative standard deviation) of 0.24% could be reached. Furthermore, such a detector with a red/yellow LED has been coupled with the FIA technique for the determination of 10(-6)M levels of cobalt.

Design study of a high-resolution breast-dedicated PET system built from cadmium zinc telluride detectors

PubMed Central

Peng, Hao; Levin, Craig S

2013-01-01

We studied the performance of a dual-panel positron emission tomography (PET) camera dedicated to breast cancer imaging using Monte Carlo simulation. The proposed system consists of two 4 cm thick 12 × 15 cm2 area cadmium zinc telluride (CZT) panels with adjustable separation, which can be put in close proximity to the breast and/or axillary nodes. Unique characteristics distinguishing the proposed system from previous efforts in breast-dedicated PET instrumentation are the deployment of CZT detectors with superior spatial and energy resolution, using a cross-strip electrode readout scheme to enable 3D positioning of individual photon interaction coordinates in the CZT, which includes directly measured photon depth-of-interaction (DOI), and arranging the detector slabs edge-on with respect to incoming 511 keV photons for high photon sensitivity. The simulation results show that the proposed CZT dual-panel PET system is able to achieve superior performance in terms of photon sensitivity, noise equivalent count rate, spatial resolution and lesion visualization. The proposed system is expected to achieve ~32% photon sensitivity for a point source at the center and a 4 cm panel separation. For a simplified breast phantom adjacent to heart and torso compartments, the peak noise equivalent count (NEC) rate is predicted to be ~94.2 kcts s−1 (breast volume: 720 cm3 and activity concentration: 3.7 kBq cm−3) for a ~10% energy window around 511 keV and ~8 ns coincidence time window. The system achieves 1 mm intrinsic spatial resolution anywhere between the two panels with a 4 cm panel separation if the detectors have DOI resolution less than 2 mm. For a 3 mm DOI resolution, the system exhibits excellent sphere resolution uniformity (σrms/mean) ≤ 10%) across a 4 cm width FOV. Simulation results indicate that the system exhibits superior hot sphere visualization and is expected to visualize 2 mm diameter spheres with a 5:1 activity concentration ratio within roughly 7

Limits in point to point resolution of MOS based pixels detector arrays

NASA Astrophysics Data System (ADS)

Fourches, N.; Desforge, D.; Kebbiri, M.; Kumar, V.; Serruys, Y.; Gutierrez, G.; Leprêtre, F.; Jomard, F.

2018-01-01

In high energy physics point-to-point resolution is a key prerequisite for particle detector pixel arrays. Current and future experiments require the development of inner-detectors able to resolve the tracks of particles down to the micron range. Present-day technologies, although not fully implemented in actual detectors, can reach a 5-μm limit, this limit being based on statistical measurements, with a pixel-pitch in the 10 μm range. This paper is devoted to the evaluation of the building blocks for use in pixel arrays enabling accurate tracking of charged particles. Basing us on simulations we will make here a quantitative evaluation of the physical and technological limits in pixel size. Attempts to design small pixels based on SOI technology will be briefly recalled here. A design based on CMOS compatible technologies that allow a reduction of the pixel size below the micrometer is introduced here. Its physical principle relies on a buried carrier-localizing collecting gate. The fabrication process needed by this pixel design can be based on existing process steps used in silicon microelectronics. The pixel characteristics will be discussed as well as the design of pixel arrays. The existing bottlenecks and how to overcome them will be discussed in the light of recent ion implantation and material characterization experiments.

An instrumentation amplifier based readout circuit for a dual element microbolometer infrared detector

NASA Astrophysics Data System (ADS)

de Waal, D. J.; Schoeman, J.

2014-06-01

The infrared band is widely used in many applications to solve problems stretching over very diverse fields, ranging from medical applications like inflammation detection to military, security and safety applications employing thermal imaging in low light conditions. At the heart of these optoelectrical systems lies a sensor used to detect incident infrared radiation, and in the case of this work our focus is on uncooled microbolometers as thermal detectors. Microbolometer based thermal detectors are limited in sensitivity by various parameters, including the detector layout and design, operating temperature, air pressure and biasing that causes self heating. Traditional microbolometers use the entire membrane surface for a single detector material. This work presents the design of a readout circuit amplifier where a dual detector element microbolometer is used, rather than the traditional single element. The concept to be investigated is based on the principle that both elements will be stimulated with a similar incoming IR signal and experience the same resistive change, thus creating a common mode signal. However, such a common mode signal will be rejected by a differential amplifier, thus one element is placed within a negative resistance converter to create a differential mode signal that is twice the magnitude of the comparable single mode signal of traditional detector designs. An instrumentation amplifier is used for the final stage of the readout amplifier circuit, as it allows for very high common mode rejection with proper trimming of the Wheatstone bridge to compensate for manufacturing tolerance. It was found that by implementing the above, improved sensitivity can be achieved.

Improved imputation accuracy of rare and low-frequency variants using population-specific high-coverage WGS-based imputation reference panel

PubMed Central

Mitt, Mario; Kals, Mart; Pärn, Kalle; Gabriel, Stacey B; Lander, Eric S; Palotie, Aarno; Ripatti, Samuli; Morris, Andrew P; Metspalu, Andres; Esko, Tõnu; Mägi, Reedik; Palta, Priit

2017-01-01

Genetic imputation is a cost-efficient way to improve the power and resolution of genome-wide association (GWA) studies. Current publicly accessible imputation reference panels accurately predict genotypes for common variants with minor allele frequency (MAF)≥5% and low-frequency variants (0.5≤MAF<5%) across diverse populations, but the imputation of rare variation (MAF<0.5%) is still rather limited. In the current study, we evaluate imputation accuracy achieved with reference panels from diverse populations with a population-specific high-coverage (30 ×) whole-genome sequencing (WGS) based reference panel, comprising of 2244 Estonian individuals (0.25% of adult Estonians). Although the Estonian-specific panel contains fewer haplotypes and variants, the imputation confidence and accuracy of imputed low-frequency and rare variants was significantly higher. The results indicate the utility of population-specific reference panels for human genetic studies. PMID:28401899

Inclusion of Population-specific Reference Panel from India to the 1000 Genomes Phase 3 Panel Improves Imputation Accuracy.

PubMed

Ahmad, Meraj; Sinha, Anubhav; Ghosh, Sreya; Kumar, Vikrant; Davila, Sonia; Yajnik, Chittaranjan S; Chandak, Giriraj R

2017-07-27

Imputation is a computational method based on the principle of haplotype sharing allowing enrichment of genome-wide association study datasets. It depends on the haplotype structure of the population and density of the genotype data. The 1000 Genomes Project led to the generation of imputation reference panels which have been used globally. However, recent studies have shown that population-specific panels provide better enrichment of genome-wide variants. We compared the imputation accuracy using 1000 Genomes phase 3 reference panel and a panel generated from genome-wide data on 407 individuals from Western India (WIP). The concordance of imputed variants was cross-checked with next-generation re-sequencing data on a subset of genomic regions. Further, using the genome-wide data from 1880 individuals, we demonstrate that WIP works better than the 1000 Genomes phase 3 panel and when merged with it, significantly improves the imputation accuracy throughout the minor allele frequency range. We also show that imputation using only South Asian component of the 1000 Genomes phase 3 panel works as good as the merged panel, making it computationally less intensive job. Thus, our study stresses that imputation accuracy using 1000 Genomes phase 3 panel can be further improved by including population-specific reference panels from South Asia.

Silicon PIN diode based electron-gamma coincidence detector system for Noble Gases monitoring.

PubMed

Khrustalev, K; Popov, V Yu; Popov, Yu S

2017-08-01

We present a new second generation SiPIN based electron-photon coincidence detector system developed by Lares Ltd. for use in the Noble Gas measurement systems of the International Monitoring System and the On-site Inspection verification regimes of the Comprehensive Nuclear-Test Ban Treaty (CTBT). The SiPIN provide superior energy resolution for electrons. Our work describes the improvements made in the second generation detector cells and the potential use of such detector systems for other applications such as In-Situ Kr-85 measurements for non-proliferation purposes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detective quantum efficiency of photon-counting x-ray detectors.

PubMed

Tanguay, Jesse; Yun, Seungman; Kim, Ho Kyung; Cunningham, Ian A

2015-01-01

Single-photon-counting (SPC) x-ray imaging has the potential to improve image quality and enable novel energy-dependent imaging methods. Similar to conventional detectors, optimizing image SPC quality will require systems that produce the highest possible detective quantum efficiency (DQE). This paper builds on the cascaded-systems analysis (CSA) framework to develop a comprehensive description of the DQE of SPC detectors that implement adaptive binning. The DQE of SPC systems can be described using the CSA approach by propagating the probability density function (PDF) of the number of image-forming quanta through simple quantum processes. New relationships are developed to describe PDF transfer through serial and parallel cascades to accommodate scatter reabsorption. Results are applied to hypothetical silicon and selenium-based flat-panel SPC detectors including the effects of reabsorption of characteristic/scatter photons from photoelectric and Compton interactions, stochastic conversion of x-ray energy to secondary quanta, depth-dependent charge collection, and electronic noise. Results are compared with a Monte Carlo study. Depth-dependent collection efficiency can result in substantial broadening of photopeaks that in turn may result in reduced DQE at lower x-ray energies (20-45 keV). Double-counting interaction events caused by reabsorption of characteristic/scatter photons may result in falsely inflated image signal-to-noise ratio and potential overestimation of the DQE. The CSA approach is extended to describe signal and noise propagation through photoelectric and Compton interactions in SPC detectors, including the effects of escape and reabsorption of emission/scatter photons. High-performance SPC systems can be achieved but only for certain combinations of secondary conversion gain, depth-dependent collection efficiency, electronic noise, and reabsorption characteristics.

Two-level optimization of composite wing structures based on panel genetic optimization

NASA Astrophysics Data System (ADS)

Liu, Boyang

load. The resulting response surface is used for wing-level optimization. In general, complex composite structures consist of several laminates. A common problem in the design of such structures is that some plies in the adjacent laminates terminate in the boundary between the laminates. These discontinuities may cause stress concentrations and may increase manufacturing difficulty and cost. We developed measures of continuity of two adjacent laminates. We studied tradeoffs between weight and continuity through a simple composite wing design. Finally, we compared the two-level optimization to a single-level optimization based on flexural lamination parameters. The single-level optimization is efficient and feasible for a wing consisting of unstiffened panels.

Prototyping of MWIR MEMS-based optical filter combined with HgCdTe detector

NASA Astrophysics Data System (ADS)

Kozak, Dmitry A.; Fernandez, Bautista; Velicu, Silviu; Kubby, Joel

2010-02-01

In the past decades, there have been several attempts to create a tunable optical detector with operation in the infrared. The drive for creating such a filter is its wide range of applications, from passive night vision to biological and chemical sensors. Such a device would combine a tunable optical filter with a wide-range detector. In this work, we propose using a Fabry-Perot interferometer centered in the mid-wave infrared (MWIR) spectrum with an HgCdTe detector. Using a MEMS-based interferometer with an integrated Bragg stack will allow in-plane operation over a wide range. Because such devices have a tendency to warp, creating less-than-perfect optical surfaces, the Fabry-Perot interferometer is prototyped using the SOI-MUMPS process to ensure desirable operation. The mechanical design is aimed at optimal optical flatness of the moving membranes and a low operating voltage. The prototype is tested for these requirements. An HgCdTe detector provides greater performance than a pyroelectic detector used in some previous work, allowing for lower noise, greater detection speed and higher sensitivity. Both a custom HgCdTe detector and commercially available pyroelectric detector are tested with commercial optical filter. In previous work, monolithic integration of HgCdTe detectors with optical filters proved to be problematic. Part of this work investigates the best approach to combining these two components, either monolithically in HgCdTe or using a hybrid packaging approach where a silicon MEMS Fabry-Perot filter is bonded at low temperature to a HgCdTe detector.

Reliability of stiffened structural panels: Two examples

NASA Technical Reports Server (NTRS)

Stroud, W. Jefferson; Davis, D. Dale, Jr.; Maring, Lise D.; Krishnamurthy, Thiagaraja; Elishakoff, Isaac

1992-01-01

The reliability of two graphite-epoxy stiffened panels that contain uncertainties is examined. For one panel, the effect of an overall bow-type initial imperfection is studied. The size of the bow is assumed to be a random variable. The failure mode is buckling. The benefits of quality control are explored by using truncated distributions. For the other panel, the effect of uncertainties in a strain-based failure criterion is studied. The allowable strains are assumed to be random variables. A geometrically nonlinear analysis is used to calculate a detailed strain distribution near an elliptical access hole in a wing panel that was tested to failure. Calculated strains are used to predict failure. Results are compared with the experimental failure load of the panel.

7 CFR 1940.968 - Rural Economic Development Review Panel Grant (Panel Grant).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 13 2013-01-01 2013-01-01 false Rural Economic Development Review Panel Grant (Panel... of Certain Rural Development Programs § 1940.968 Rural Economic Development Review Panel Grant (Panel... associated with a State rural economic development review panel. (b) Objective. The objective of the Panel...

Amorphous Silicon Based Neutron Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Liwei

2004-12-12

Various large-scale neutron sources already build or to be constructed, are important for materials research and life science research. For all these neutron sources, neutron detectors are very important aspect. However, there is a lack of a high-performance and low-cost neutron beam monitor that provides time and temporal resolution. The objective of this SBIR Phase I research, collaboratively performed by Midwest Optoelectronics, LLC (MWOE), the University of Toledo (UT) and Oak Ridge National Laboratory (ORNL), is to demonstrate the feasibility for amorphous silicon based neutron beam monitors that are pixilated, reliable, durable, fully packaged, and fabricated with high yield usingmore » low-cost method. During the Phase I effort, work as been focused in the following areas: 1) Deposition of high quality, low-defect-density, low-stress a-Si films using very high frequency plasma enhanced chemical vapor deposition (VHF PECVD) at high deposition rate and with low device shunting; 2) Fabrication of Si/SiO2/metal/p/i/n/metal/n/i/p/metal/SiO2/ device for the detection of alpha particles which are daughter particles of neutrons through appropriate nuclear reactions; and 3) Testing of various devices fabricated for alpha and neutron detection; As the main results: · High quality, low-defect-density, low-stress a-Si films have been successfully deposited using VHF PECVD on various low-cost substrates; · Various single-junction and double junction detector devices have been fabricated; · The detector devices fabricated have been systematically tested and analyzed. · Some of the fabricated devices are found to successfully detect alpha particles. Further research is required to bring this Phase I work beyond the feasibility demonstration toward the final prototype devices. The success of this project will lead to a high-performance, low-cost, X-Y pixilated neutron beam monitor that could be used in all of the neutron facilities worldwide. In addition, the

Development of a Monte Carlo Simulation for APD-Based PET Detectors Using a Continuous Scintillating Crystal

NASA Astrophysics Data System (ADS)

Clowes, P.; Mccallum, S.; Welch, A.

2006-10-01

We are currently developing a multilayer avalanche photodiode (APD)-based detector for use in positron emission tomography (PET), which utilizes thin continuous crystals. In this paper, we developed a Monte Carlo-based simulation to aid in the design of such detectors. We measured the performance of a detector comprising a single thin continuous crystal (3.1 mm times 9.5 mm times 9.5 mm) of lutetium yttrium ortho-silicate (LYSO) and an APD array (4times4) elements; each element 1.6 mm2 and on a 2.3 mm pitch. We showed that a spatial resolution of better than 2.12 mm is achievable throughout the crystal provided that we adopt a Statistics Based Positioning (SBP) Algorithm. We then used Monte Carlo simulation to model the behavior of the detector. The accuracy of the Monte Carlo simulation was verified by comparing measured and simulated parent datasets (PDS) for the SBP algorithm. These datasets consisted of data for point sources at 49 positions uniformly distributed over the detector area. We also calculated the noise in the detector circuit and verified this value by measurement. The noise value was included in the simulation. We show that the performance of the simulation closely matches the measured performance. The simulations were extended to investigate the effect of different noise levels on positioning accuracy. This paper showed that if modest improvements could be made in the circuit noise then positioning accuracy would be greatly improved. In summary, we have developed a model that can be used to simulate the performance of a variety of APD-based continuous crystal PET detectors

Wideband digital frequency detector with subtraction-based phase comparator for frequency modulation atomic force microscopy.

PubMed

Mitani, Yuji; Kubo, Mamoru; Muramoto, Ken-ichiro; Fukuma, Takeshi

2009-08-01

We have developed a wideband digital frequency detector for high-speed frequency modulation atomic force microscopy (FM-AFM). We used a subtraction-based phase comparator (PC) in a phase-locked loop circuit instead of a commonly used multiplication-based PC, which has enhanced the detection bandwidth to 100 kHz. The quantitative analysis of the noise performance revealed that the internal noise from the developed detector is small enough to provide the theoretically limited noise performance in FM-AFM experiments in liquid. FM-AFM imaging of mica in liquid was performed with the developed detector, showing its stability and applicability to true atomic-resolution imaging in liquid.

Interactive optical panel

DOEpatents

Veligdan, J.T.

1995-10-03

An interactive optical panel assembly includes an optical panel having a plurality of ribbon optical waveguides stacked together with opposite ends thereof defining panel first and second faces. A light source provides an image beam to the panel first face for being channeled through the waveguides and emitted from the panel second face in the form of a viewable light image. A remote device produces a response beam over a discrete selection area of the panel second face for being channeled through at least one of the waveguides toward the panel first face. A light sensor is disposed across a plurality of the waveguides for detecting the response beam therein for providing interactive capability. 10 figs.

Online pretreatment verification of high-dose rate brachytherapy using an imaging panel

NASA Astrophysics Data System (ADS)

Fonseca, Gabriel P.; Podesta, Mark; Bellezzo, Murillo; Van den Bosch, Michiel R.; Lutgens, Ludy; Vanneste, Ben G. L.; Voncken, Robert; Van Limbergen, Evert J.; Reniers, Brigitte; Verhaegen, Frank

2017-07-01

Brachytherapy is employed to treat a wide variety of cancers. However, an accurate treatment verification method is currently not available. This study describes a pre-treatment verification system that uses an imaging panel (IP) to verify important aspects of the treatment plan. A detailed modelling of the IP was only possible with an extensive calibration performed using a robotic arm. Irradiations were performed with a high dose rate (HDR) 192Ir source within a water phantom. An empirical fit was applied to measure the distance between the source and the detector so 3D Cartesian coordinates of the dwell positions can be obtained using a single panel. The IP acquires 7.14 fps to verify the dwell times, dwell positions and air kerma strength (Sk). A gynecological applicator was used to create a treatment plan that was registered with a CT image of the water phantom used during the experiments for verification purposes. Errors (shifts, exchanged connections and wrong dwell times) were simulated to verify the proposed verification system. Cartesian source positions (panel measurement plane) have a standard deviation of about 0.02 cm. The measured distance between the source and the panel (z-coordinate) have a standard deviation up to 0.16 cm and maximum absolute error of  ≈0.6 cm if the signal is close to sensitive limit of the panel. The average response of the panel is very linear with Sk. Therefore, Sk measurements can be performed with relatively small errors. The measured dwell times show a maximum error of 0.2 s which is consistent with the acquisition rate of the panel. All simulated errors were clearly identified by the proposed system. The use of IPs is not common in brachytherapy, however, it provides considerable advantages. It was demonstrated that the IP can accurately measure Sk, dwell times and dwell positions.

Online pretreatment verification of high-dose rate brachytherapy using an imaging panel.

PubMed

Fonseca, Gabriel P; Podesta, Mark; Bellezzo, Murillo; Van den Bosch, Michiel R; Lutgens, Ludy; Vanneste, Ben G L; Voncken, Robert; Van Limbergen, Evert J; Reniers, Brigitte; Verhaegen, Frank

2017-07-07

Brachytherapy is employed to treat a wide variety of cancers. However, an accurate treatment verification method is currently not available. This study describes a pre-treatment verification system that uses an imaging panel (IP) to verify important aspects of the treatment plan. A detailed modelling of the IP was only possible with an extensive calibration performed using a robotic arm. Irradiations were performed with a high dose rate (HDR) 192 Ir source within a water phantom. An empirical fit was applied to measure the distance between the source and the detector so 3D Cartesian coordinates of the dwell positions can be obtained using a single panel. The IP acquires 7.14 fps to verify the dwell times, dwell positions and air kerma strength (Sk). A gynecological applicator was used to create a treatment plan that was registered with a CT image of the water phantom used during the experiments for verification purposes. Errors (shifts, exchanged connections and wrong dwell times) were simulated to verify the proposed verification system. Cartesian source positions (panel measurement plane) have a standard deviation of about 0.02 cm. The measured distance between the source and the panel (z-coordinate) have a standard deviation up to 0.16 cm and maximum absolute error of  ≈0.6 cm if the signal is close to sensitive limit of the panel. The average response of the panel is very linear with Sk. Therefore, Sk measurements can be performed with relatively small errors. The measured dwell times show a maximum error of 0.2 s which is consistent with the acquisition rate of the panel. All simulated errors were clearly identified by the proposed system. The use of IPs is not common in brachytherapy, however, it provides considerable advantages. It was demonstrated that the IP can accurately measure Sk, dwell times and dwell positions.

Multi-class geospatial object detection and geographic image classification based on collection of part detectors

NASA Astrophysics Data System (ADS)

Cheng, Gong; Han, Junwei; Zhou, Peicheng; Guo, Lei

2014-12-01

The rapid development of remote sensing technology has facilitated us the acquisition of remote sensing images with higher and higher spatial resolution, but how to automatically understand the image contents is still a big challenge. In this paper, we develop a practical and rotation-invariant framework for multi-class geospatial object detection and geographic image classification based on collection of part detectors (COPD). The COPD is composed of a set of representative and discriminative part detectors, where each part detector is a linear support vector machine (SVM) classifier used for the detection of objects or recurring spatial patterns within a certain range of orientation. Specifically, when performing multi-class geospatial object detection, we learn a set of seed-based part detectors where each part detector corresponds to a particular viewpoint of an object class, so the collection of them provides a solution for rotation-invariant detection of multi-class objects. When performing geographic image classification, we utilize a large number of pre-trained part detectors to discovery distinctive visual parts from images and use them as attributes to represent the images. Comprehensive evaluations on two remote sensing image databases and comparisons with some state-of-the-art approaches demonstrate the effectiveness and superiority of the developed framework.

Estimate of the neutron fields in ATLAS based on ATLAS-MPX detectors data

NASA Astrophysics Data System (ADS)

Bouchami, J.; Dallaire, F.; Gutiérrez, A.; Idarraga, J.; Král, V.; Leroy, C.; Picard, S.; Pospíšil, S.; Scallon, O.; Solc, J.; Suk, M.; Turecek, D.; Vykydal, Z.; Žemlièka, J.

2011-01-01

The ATLAS-MPX detectors are based on Medipix2 silicon devices designed by CERN for the detection of different types of radiation. These detectors are covered with converting layers of 6LiF and polyethylene (PE) to increase their sensitivity to thermal and fast neutrons, respectively. These devices allow the measurement of the composition and spectroscopic characteristics of the radiation field in ATLAS, particularly of neutrons. These detectors can operate in low or high preset energy threshold mode. The signature of particles interacting in a ATLAS-MPX detector at low threshold are clusters of adjacent pixels with different size and form depending on their type, energy and incidence angle. The classification of particles into different categories can be done using the geometrical parameters of these clusters. The Medipix analysis framework (MAFalda) — based on the ROOT application — allows the recognition of particle tracks left in ATLAS-MPX devices located at various positions in the ATLAS detector and cavern. The pattern recognition obtained from the application of MAFalda was configured to distinguish the response of neutrons from other radiation. The neutron response at low threshold is characterized by clusters of adjoining pixels (heavy tracks and heavy blobs) left by protons and heavy ions resulting from neutron interactions in the converting layers of the ATLAS-MPX devices. The neutron detection efficiency of ATLAS-MPX devices has been determined by the exposure of two detectors of reference to radionuclide sources of neutrons (252Cf and 241AmBe). With these results, an estimate of the neutrons fields produced at the devices locations during ATLAS operation was done.

A Practical, Hardware Friendly MMSE Detector for MIMO-OFDM-Based Systems

NASA Astrophysics Data System (ADS)

Kim, Hun Seok; Zhu, Weijun; Bhatia, Jatin; Mohammed, Karim; Shah, Anish; Daneshrad, Babak

2008-12-01

Design and implementation of a highly optimized MIMO (multiple-input multiple-output) detector requires cooptimization of the algorithm with the underlying hardware architecture. Special attention must be paid to application requirements such as throughput, latency, and resource constraints. In this work, we focus on a highly optimized matrix inversion free [InlineEquation not available: see fulltext.] MMSE (minimum mean square error) MIMO detector implementation. The work has resulted in a real-time field-programmable gate array-based implementation (FPGA-) on a Xilinx Virtex-2 6000 using only 9003 logic slices, 66 multipliers, and 24 Block RAMs (less than 33% of the overall resources of this part). The design delivers over 420 Mbps sustained throughput with a small 2.77-microsecond latency. The designed [InlineEquation not available: see fulltext.] linear MMSE MIMO detector is capable of complying with the proposed IEEE 802.11n standard.

Stationary Digital Tomosynthesis System for Early Detection of Breast Tumors

DTIC Science & Technology

2011-05-01

selenium flat panel detector. Proc. SPIE 2005. 5745: p. 529-540 4. Kopans, D.B., Breast Imaging. 2 ed. 1997, New York Lippincott Williams and...same. 2005. 8. M. Bissonnette, et al. Digital breast tomosynthesis using an amorphous selenium flat panel detector. in Medical Imaging 2005...tomosynthesis system with selenium based flat panel detector. Proc of SPIE, Physics of Medical Imaging, 2005. 5745. 12

An educational distributed Cosmic Ray detector network based on ArduSiPM

NASA Astrophysics Data System (ADS)

Bocci, V.; Chiodi, G.; Fresch, P.; Iacoangeli, F.; Recchia, L.

2017-10-01

The advent of high performance microcontrollers equipped with analog and digital peripherals, makes the design of a complete particle detector and a relative acquisition system on a single microcontroller chip possible. The existence of a world wide data infrastructure such as the internet, allows for the conception of a distributed network of cheap detectors able to elaborate and send data as well as to respond to setting commands. The internet infrastructure enables the distribution of the absolute time, with precision of a few milliseconds, to all devices independently of their physical location, when the sky view is accessible it possible to use a GPS module to reach synchronization of tens of nanoseconds. These devices can be far apart from each other and their relative distance can range from a few meters to thousands of kilometers. This allows for the design of a crowdsourcing experiment of citizen science, based on the use of many small scintillation-based particle detectors to monitor the high energetic cosmic ray and the radiation environment.

Combination of CT scanning and fluoroscopy imaging on a flat-panel CT scanner

NASA Astrophysics Data System (ADS)

Grasruck, M.; Gupta, R.; Reichardt, B.; Suess, Ch.; Schmidt, B.; Stierstorfer, K.; Popescu, S.; Brady, T.; Flohr, T.

2006-03-01

We developed and evaluated a prototype flat-panel detector based Volume CT (fpVCT) scanner. The fpVCT scanner consists of a Varian 4030CB a-Si flat-panel detector mounted in a multi slice CT-gantry (Siemens Medical Solutions). It provides a 25 cm field of view with 18 cm z-coverage at the isocenter. In addition to the standard tomographic scanning, fpVCT allows two new scan modes: (1) fluoroscopic imaging from any arbitrary rotation angle, and (2) continuous, time-resolved tomographic scanning of a dynamically changing viewing volume. Fluoroscopic imaging is feasible by modifying the standard CT gantry so that the imaging chain can be oriented along any user-selected rotation angle. Scanning with a stationary gantry, after it has been oriented, is equivalent to a conventional fluoroscopic examination. This scan mode enables combined use of high-resolution tomography and real-time fluoroscopy with a clinically usable field of view in the z direction. The second scan mode allows continuous observation of a timeevolving process such as perfusion. The gantry can be continuously rotated for up to 80 sec, with the rotation time ranging from 3 to 20 sec, to gather projection images of a dynamic process. The projection data, that provides a temporal log of the viewing volume, is then converted into multiple image stacks that capture the temporal evolution of a dynamic process. Studies using phantoms, ex vivo specimens, and live animals have confirmed that these new scanning modes are clinically usable and offer a unique view of the anatomy and physiology that heretofore has not been feasible using static CT scanning. At the current level of image quality and temporal resolution, several clinical applications such a dynamic angiography, tumor enhancement pattern and vascularity studies, organ perfusion, and interventional applications are in reach.

Thin film photovoltaic panel and method

DOEpatents

Ackerman, Bruce; Albright, Scot P.; Jordan, John F.

1991-06-11

A thin film photovoltaic panel includes a backcap for protecting the active components of the photovoltaic cells from adverse environmental elements. A spacing between the backcap and a top electrode layer is preferably filled with a desiccant to further reduce water vapor contamination of the environment surrounding the photovoltaic cells. The contamination of the spacing between the backcap and the cells may be further reduced by passing a selected gas through the spacing subsequent to sealing the backcap to the base of the photovoltaic panels, and once purged this spacing may be filled with an inert gas. The techniques of the present invention are preferably applied to thin film photovoltaic panels each formed from a plurality of photovoltaic cells arranged on a vitreous substrate. The stability of photovoltaic conversion efficiency remains relatively high during the life of the photovoltaic panel, and the cost of manufacturing highly efficient panels with such improved stability is significantly reduced.

On a Three-Channel Cosmic Ray Detector based on Aluminum Blocks

NASA Astrophysics Data System (ADS)

Arceo, L.; Félix, J.

2017-10-01

There are many general purpose cosmic ray detectors based on plastic scintillators and electronic boards from the market. This is a new cosmic ray detector designed on three 2.54 cm × 5.08 cm × 20.32 cm Aluminum blocks in stack arrangement, and three Hamamatsu S12572-100P photodiodes. The photodiode board, the passive electronic board, and the discriminator board are own designed. The electronic signals are stored with a CompactRIO -cRIO- by National Instruments. It is presented the design, the construction, the data acquisition system algorithm, and the preliminary physical results.

Innovation in values based public health nursing student selection: A qualitative evaluation of candidate and selection panel member perspectives.

PubMed

McGraw, Caroline; Abbott, Stephen; Brook, Judy

2018-02-19

Values based recruitment emerges from the premise that a high degree of value congruence, or the extent to which an individual's values are similar to those of the health organization in which they work, leads to organizational effectiveness. The aim of this evaluation was to explore how candidates and selection panel members experienced and perceived innovative methods of values based public health nursing student selection. The evaluation was framed by a qualitative exploratory design involving semi-structured interviews and a group exercise. Data were thematically analyzed. Eight semi-structured interviews were conducted with selection panel members. Twenty-two successful candidates took part in a group exercise. The use of photo elicitation interviews and situational judgment questions in the context of selection to a university-run public health nursing educational program was explored. While candidates were ambivalent about the use of photo elicitation interviews, with some misunderstanding the task, selection panel members saw the benefits for improving candidate expression and reducing gaming and deception. Situational interview questions were endorsed by candidates and selection panel members due to their fidelity to real-life problems and the ability of panel members to discern value congruence from candidates' responses. Both techniques offered innovative solutions to candidate selection for entry to the public health nursing education program. © 2018 Wiley Periodicals, Inc.

The Effect of Personalization on Smartphone-Based Fall Detectors

PubMed Central

Medrano, Carlos; Plaza, Inmaculada; Igual, Raúl; Sánchez, Ángel; Castro, Manuel

2016-01-01

The risk of falling is high among different groups of people, such as older people, individuals with Parkinson's disease or patients in neuro-rehabilitation units. Developing robust fall detectors is important for acting promptly in case of a fall. Therefore, in this study we propose to personalize smartphone-based detectors to boost their performance as compared to a non-personalized system. Four algorithms were investigated using a public dataset: three novelty detection algorithms—Nearest Neighbor (NN), Local Outlier Factor (LOF) and One-Class Support Vector Machine (OneClass-SVM)—and a traditional supervised algorithm, Support Vector Machine (SVM). The effect of personalization was studied for each subject by considering two different training conditions: data coming only from that subject or data coming from the remaining subjects. The area under the receiver operating characteristic curve (AUC) was selected as the primary figure of merit. The results show that there is a general trend towards the increase in performance by personalizing the detector, but the effect depends on the individual being considered. A personalized NN can reach the performance of a non-personalized SVM (average AUC of 0.9861 and 0.9795, respectively), which is remarkable since NN only uses activities of daily living for training. PMID:26797614

A Review of Accelerometry-Based Wearable Motion Detectors for Physical Activity Monitoring

PubMed Central

Yang, Che-Chang; Hsu, Yeh-Liang

2010-01-01

Characteristics of physical activity are indicative of one’s mobility level, latent chronic diseases and aging process. Accelerometers have been widely accepted as useful and practical sensors for wearable devices to measure and assess physical activity. This paper reviews the development of wearable accelerometry-based motion detectors. The principle of accelerometry measurement, sensor properties and sensor placements are first introduced. Various research using accelerometry-based wearable motion detectors for physical activity monitoring and assessment, including posture and movement classification, estimation of energy expenditure, fall detection and balance control evaluation, are also reviewed. Finally this paper reviews and compares existing commercial products to provide a comprehensive outlook of current development status and possible emerging technologies. PMID:22163626

Development of panel loudspeaker system: design, evaluation and enhancement.

PubMed

Bai, M R; Huang, T

2001-06-01

Panel speakers are investigated in terms of structural vibration and acoustic radiation. A panel speaker primarily consists of a panel and an inertia exciter. Contrary to conventional speakers, flexural resonance is encouraged such that the panel vibrates as randomly as possible. Simulation tools are developed to facilitate system integration of panel speakers. In particular, electro-mechanical analogy, finite element analysis, and fast Fourier transform are employed to predict panel vibration and the acoustic radiation. Design procedures are also summarized. In order to compare the panel speakers with the conventional speakers, experimental investigations were undertaken to evaluate frequency response, directional response, sensitivity, efficiency, and harmonic distortion of both speakers. The results revealed that the panel speakers suffered from a problem of sensitivity and efficiency. To alleviate the problem, a woofer using electronic compensation based on H2 model matching principle is utilized to supplement the bass response. As indicated in the result, significant improvement over the panel speaker alone was achieved by using the combined panel-woofer system.

ICP etching for InAs-based InAs/GaAsSb superlattice long wavelength infrared detectors

NASA Astrophysics Data System (ADS)

Huang, Min; Chen, Jianxin; Xu, Jiajia; Wang, Fangfang; Xu, Zhicheng; He, Li

2018-05-01

In this work, we study and report the dry etching processes for InAs-based InAs/GaAsSb strain-free superlattice long wavelength infrared (LWIR) detectors. The proper etching parameters were first obtained through the parametric studies of Inductively Coupled Plasma (ICP) etching of both InAs and GaSb bulk materials in Cl2/N2 plasmas. Then an InAs-based InAs/GaAsSb superlattice LWIR detector with PπN structure was fabricated by using the optimized etching parameters. At 80 K, the detector exhibits a 100% cut-off wavelength of 12 μm and a responsivity of 1.5 A/W. Moreover, the dark current density of the device under a bias of -200 mV reaches 5.5 × 10-4 A/cm2, and the R0A is 15 Ω cm2. Our results pave the way towards InAs-based superlattice LWIR detectors with better performances.

Deterministic and reliability based optimization of integrated thermal protection system composite panel using adaptive sampling techniques

NASA Astrophysics Data System (ADS)

Ravishankar, Bharani

Conventional space vehicles have thermal protection systems (TPS) that provide protection to an underlying structure that carries the flight loads. In an attempt to save weight, there is interest in an integrated TPS (ITPS) that combines the structural function and the TPS function. This has weight saving potential, but complicates the design of the ITPS that now has both thermal and structural failure modes. The main objectives of this dissertation was to optimally design the ITPS subjected to thermal and mechanical loads through deterministic and reliability based optimization. The optimization of the ITPS structure requires computationally expensive finite element analyses of 3D ITPS (solid) model. To reduce the computational expenses involved in the structural analysis, finite element based homogenization method was employed, homogenizing the 3D ITPS model to a 2D orthotropic plate. However it was found that homogenization was applicable only for panels that are much larger than the characteristic dimensions of the repeating unit cell in the ITPS panel. Hence a single unit cell was used for the optimization process to reduce the computational cost. Deterministic and probabilistic optimization of the ITPS panel required evaluation of failure constraints at various design points. This further demands computationally expensive finite element analyses which was replaced by efficient, low fidelity surrogate models. In an optimization process, it is important to represent the constraints accurately to find the optimum design. Instead of building global surrogate models using large number of designs, the computational resources were directed towards target regions near constraint boundaries for accurate representation of constraints using adaptive sampling strategies. Efficient Global Reliability Analyses (EGRA) facilitates sequentially sampling of design points around the region of interest in the design space. EGRA was applied to the response surface construction of

Target-based optimization of advanced gravitational-wave detector network operations

NASA Astrophysics Data System (ADS)

Szölgyén, Á.; Dálya, G.; Gondán, L.; Raffai, P.

2017-04-01

We introduce two novel time-dependent figures of merit for both online and offline optimizations of advanced gravitational-wave (GW) detector network operations with respect to (i) detecting continuous signals from known source locations and (ii) detecting GWs of neutron star binary coalescences from known local galaxies, which thereby have the highest potential for electromagnetic counterpart detection. For each of these scientific goals, we characterize an N-detector network, and all its (N  -  1)-detector subnetworks, to identify subnetworks and individual detectors (key contributors) that contribute the most to achieving the scientific goal. Our results show that aLIGO-Hanford is expected to be the key contributor in 2017 to the goal of detecting GWs from the Crab pulsar within the network of LIGO and Virgo detectors. For the same time period and for the same network, both LIGO detectors are key contributors to the goal of detecting GWs from the Vela pulsar, as well as to detecting signals from 10 high interest pulsars. Key contributors to detecting continuous GWs from the Galactic Center can only be identified for finite time intervals within each sidereal day with either the 3-detector network of the LIGO and Virgo detectors in 2017, or the 4-detector network of the LIGO, Virgo, and KAGRA detectors in 2019-2020. Characterization of the LIGO-Virgo detectors with respect to goal (ii) identified the two LIGO detectors as key contributors. Additionally, for all analyses, we identify time periods within a day when lock losses or scheduled service operations could result with the least amount of signal-to-noise or transient detection probability loss for a detector network.

65. DETAIL OF ASSISTANT LAUNCH CONTROLLER AND LAUNCH CONTROLLER PANELS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

65. DETAIL OF ASSISTANT LAUNCH CONTROLLER AND LAUNCH CONTROLLER PANELS LOCATED NEAR CENTER OF SLC-3E CONTROL ROOM. NOTE 30-CHANNEL COMMUNICATIONS PANELS. PAYLOAD ENVIRONMENTAL CONTROL AND MONITORING PANELS (LEFT) AND LAUNCH OPERATORS PANEL (RIGHT) IN BACKGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Structural composite panel performance under long-term load

Treesearch

Theodore L. Laufenberg

1988-01-01

Information on the performance of wood-based structural composite panels under long-term load is currently needed to permit their use in engineered assemblies and systems. A broad assessment of the time-dependent properties of panels is critical for creating databases and models of the creep-rupture phenomenon that lead to reliability-based design procedures. This...

Assembling and Using an LED-Based Detector to Monitor Absorbance Changes during Acid-Base Titrations

ERIC Educational Resources Information Center

Santos, Willy G.; Cavalheiro, E´der T. G.

2015-01-01

A simple photometric assembly based in an LED as a light source and a photodiode as a detector is proposed in order to follow the absorbance changes as a function of the titrant volume added during the course of acid-base titrations in the presence of a suitable visual indicator. The simplicity and low cost of the electronic device allow the…

Performance evaluation of a lossy transmission lines based diode detector at cryogenic temperature.

PubMed

Villa, E; Aja, B; de la Fuente, L; Artal, E

2016-01-01

This work is focused on the design, fabrication, and performance analysis of a square-law Schottky diode detector based on lossy transmission lines working under cryogenic temperature (15 K). The design analysis of a microwave detector, based on a planar gallium-arsenide low effective Schottky barrier height diode, is reported, which is aimed for achieving large input return loss as well as flat sensitivity versus frequency. The designed circuit demonstrates good sensitivity, as well as a good return loss in a wide bandwidth at Ka-band, at both room (300 K) and cryogenic (15 K) temperatures. A good sensitivity of 1000 mV/mW and input return loss better than 12 dB have been achieved when it works as a zero-bias Schottky diode detector at room temperature, increasing the sensitivity up to a minimum of 2200 mV/mW, with the need of a DC bias current, at cryogenic temperature.

Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors.

PubMed

Gair, Jonathan R; Vallisneri, Michele; Larson, Shane L; Baker, John G

2013-01-01

We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ∼ 10 -5 - 1 Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional gravitational fields other than the metric; the number and tensorial nature of gravitational-wave polarization states; the velocity of propagation of gravitational waves; the binding energy and gravitational-wave radiation of binaries, and therefore the time evolution of binary inspirals; the strength and shape of the waves emitted from binary mergers and ringdowns; the true nature of astrophysical black holes; and much more. The strength of this science alone calls for the swift implementation of a space-based detector; the remarkable richness of astrophysics, astronomy, and cosmology in the low-frequency gravitational-wave band make the case even stronger.

Modeling of radiation damage recovery in particle detectors based on GaN

NASA Astrophysics Data System (ADS)

Gaubas, E.; Ceponis, T.; Pavlov, J.

2015-12-01

The pulsed characteristics of the capacitor-type and PIN diode type detectors based on GaN have been simulated using the dynamic and drift-diffusion models. The drift-diffusion current simulations have been implemented by employing the commercial software package Synopsys TCAD Sentaurus. The bipolar drift regime has been analyzed. The possible internal gain in charge collection through carrier multiplication processes determined by impact ionization has been considered in order to compensate carrier lifetime reduction due to radiation defects introduced into GaN material of detector.

Development of a Timepix based detector for the NanoXCT project

NASA Astrophysics Data System (ADS)

Nachtrab, F.; Hofmann, T.; Speier, C.; Lučić, J.; Firsching, M.; Uhlmann, N.; Takman, P.; Heinzl, C.; Holmberg, A.; Krumm, M.; Sauerwein, C.

2015-11-01

The NanoXCT EU FP7 project [1] aims at developing a laboratory, i.e. bench top sized X-ray nano-CT system with a large field-of-view (FOV) for non-destructive testing needs in the micro- and nano-technology sector. The targeted voxel size is 50 nm at 0.175 mm FOV, the maximum FOV is 1 mm at 285 nm voxel size. Within the project a suitable X-ray source, detector and manipulation system have been developed. The system concept [2] omits the use of X-ray optics, to be able to provide a large FOV of up to 1 mm and to preserve the flexibility of state-of-the-art micro-CT systems. The targeted resolution will be reached via direct geometric magnification made possible by the development of a specialized high-flux nano-focus transmission X-ray tube. The end-user's demand for elemental analysis will be covered by energy-resolved measurement techniques, in particular a K-edge imaging method. Timepix [3] modules were chosen as the basis for the detector system, since a photon counting detector is advantageous for the long exposure times that come with very small focal spot sizes. Additional advantages are the small pixel size and adjustable energy threshold. To fulfill the requirements on field-of-view, a detector width 0> 300 pixels was needed. The NanoXCT detector consists of four Hexa modules with 500 μm silicon sensors supplied by X-ray Imaging Europe. An adapter board was developed to connect all four modules to one Fitpix3 readout. The final detector has an active area of 3072 × 512 pixels or approximately 17 × 3 cm2.In this contribution we present the development of the Timepix based NanoXCT detector, it's application in the NanoXCT project for CT and material specific measurements and the current status of results.

Efficiency of geometric designs of flexible solar panels: mathematical simulation

NASA Astrophysics Data System (ADS)

Marciniak, Malgorzata; Hassebo, Yasser; Enriquez-Torres, Delfino; Serey-Roman, Maria Ignacia

2017-09-01

The purpose of this study is to analyze various surfaces of flexible solar panels and compare them to the traditional at panels mathematically. We evaluated the efficiency based on the integral formulas that involve flux. We performed calculations for flat panels with different positions, a cylindrical panel, conical panels with various opening angles and segments of a spherical panel. Our results indicate that the best efficiency per unit area belongs to particular segments of spherically-shaped panels. In addition, we calculated the optimal opening angle of a cone-shaped panel that maximizes the annual accumulation of the sun radiation per unit area. The considered shapes are presented below with a suggestion for connections of the cells.

Quiet Honeycomb Panels

NASA Technical Reports Server (NTRS)

Palumbo, Daniel L.; Klos, Jacob

2010-01-01

Sandwich honeycomb composite panels are lightweight and strong, and, therefore, provide a reasonable alternative to the aluminum ring frame/stringer architecture currently used for most aircraft airframes. The drawback to honeycomb panels is that they radiate noise into the aircraft cabin veil- efficiently provoking the need for additional sound treatment which adds weight and reduces the material's cost advantage. A series of honeycomb panels was made -hick incorporated different design strategies aimed at reducing the honeycomb panels' radiation efficiency while at the same time maintaining their strength. The majority of the designs were centered around the concept of creating areas of reduced stiffness in the panel by adding voids and recesses to the core. The effort culminated with a reinforced/recessed panel which had 6 dB higher transmission loss than the baseline solid core panel while maintaining comparable strength.

Interactive optical panel

DOEpatents

Veligdan, James T.

1995-10-03

An interactive optical panel assembly 34 includes an optical panel 10 having a plurality of ribbon optical waveguides 12 stacked together with opposite ends thereof defining panel first and second faces 16, 18. A light source 20 provides an image beam 22 to the panel first face 16 for being channeled through the waveguides 12 and emitted from the panel second face 18 in the form of a viewable light image 24a. A remote device 38 produces a response beam 40 over a discrete selection area 36 of the panel second face 18 for being channeled through at least one of the waveguides 12 toward the panel first face 16. A light sensor 42,50 is disposed across a plurality of the waveguides 12 for detecting the response beam 40 therein for providing interactive capability.

Clinical performance of a prototype flat-panel digital detector for general radiography

NASA Astrophysics Data System (ADS)

Huda, Walter; Scalzetti, Ernest M.; Roskopf, Marsha L.; Geiger, Robert

2001-08-01

Digital radiographs obtained using a prototype Digital Radiography System (Stingray) were compared with those obtained using conventional screen-film. Forty adult volunteers each had two identical radiographs taken at the same level of radiation exposure, one using screen-film and the other the digital detector. Each digital image was processed by hand to ensure that the printed quality was optimal. Ten radiologists compared the diagnostic image quality of the digital images with the corresponding film radiographs using a seven point ranking scheme.

High-temperature performance of gallium-nitride-based pin alpha-particle detectors grown on sapphire substrates

NASA Astrophysics Data System (ADS)

Zhu, Zhifu; Zhang, Heqiu; Liang, Hongwei; Tang, Bin; Peng, Xincun; Liu, Jianxun; Yang, Chao; Xia, Xiaochuan; Tao, Pengcheng; Shen, Rensheng; Zou, Jijun; Du, Guotong

2018-06-01

The temperature-dependent radiation-detection performance of an alpha-particle detector that was based on a gallium-nitride (GaN)-based pin structure was studied from 290 K to 450 K. Current-voltage-temperature measurements (I-V-T) of the reverse bias show the exponential dependence of leakage currents on the voltage and temperature. The current transport mechanism of the GaN-based pin diode from the reverse bias I-V fitting was analyzed. The temperature-dependent pulse-height spectra of the detectors were studied using an 241 Am alpha-particle source at a reverse bias of 10 V, and the peak positions shifted from 534 keV at 290 K to 490 keV at 450 K. The variation of full width at half maximum (FWHM) from 282 keV at 290 K to 292 keV at 450 K is almost negligible. The GaN-based pin detectors are highly promising for high-temperature environments up to 450 K.

Physical characteristics of GE Senographe Essential and DS digital mammography detectors.

PubMed

Ghetti, Caterina; Borrini, Adriano; Ortenzia, Ornella; Rossi, Raffaella; Ordóñez, Pedro L

2008-02-01

The purpose of this study was to investigate physical characteristics of two full field digital mammography (FFDM) systems (GE Senographe Essential and DS). Both are indirect conversion (x ray to light) alpha-Si flat panels coupled with a CsI(Tl) scintillator. The examined systems have the same pixel size (100 microm) but a different field of view: a conventional size 23 x 19.2 cm2 and a large field 24 X 30.7 cm2, specifically designed to image large breasts. In the GE Senographe Essential model relevant improvements in flat panel design were implemented and new deposition tools for metal, alpha-Si, and CsI(Tl) were introduced by GE. These changes in detector design are expected to be beneficial for advanced applications such as breast tomosynthesis. The presampling modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) were measured for a wide range of exposure (25-240 microGy) with a RQA-M2 technique (28 kVp with a Mo/Mo target/filter combination and 2 mm of additional aluminum filtration). At 1, 2, and at 4 lp/mm MTF is equal to 0.9, 0.76, and 0.46 for the conventional field detector and to 0.85, 0.59, and 0.24 for the large field detector. The latter detector exhibits an improved NNPS due to a lower electronic noise and a better DQE that reaches 60%. In addition a contrast-detail analysis was performed with CDMAM 3.4 phantom and CDCOM software: GE Senographe DS showed statistically significant poorer detection ability in comparison with the GE Senographe Essential. These results could have been expected, at least qualitatively, considering the relative DQE of the two systems.

Applications of a micro-pixel chamber (μPIC) based, time-resolved neutron imaging detector at pulsed neutron beams

NASA Astrophysics Data System (ADS)

Parker, J. D.; Harada, M.; Hattori, K.; Iwaki, S.; Kabuki, S.; Kishimoto, Y.; Kubo, H.; Kurosawa, S.; Matsuoka, Y.; Miuchi, K.; Mizumoto, T.; Nishimura, H.; Oku, T.; Sawano, T.; Shinohara, T.; Suzuki, J.-I.; Takada, A.; Tanimori, T.; Ueno, K.; Ikeno, M.; Tanaka, M.; Uchida, T.

2014-04-01

The realization of high-intensity, pulsed spallation neutron sources such as J-PARC in Japan and SNS in the US has brought time-of-flight (TOF) based neutron techniques to the fore and spurred the development of new detector technologies. When combined with high-resolution imaging, TOF-based methods become powerful tools for direct imaging of material properties, including crystal structure/internal strain, isotopic/temperature distributions, and internal and external magnetic fields. To carry out such measurements in the high-intensities and high gamma backgrounds found at spallation sources, we have developed a new time-resolved neutron imaging detector employing a micro-pattern gaseous detector known as the micro-pixel chamber (μPIC) coupled with a field-programmable-gate-array-based data acquisition system. The detector combines 100μm-level (σ) spatial and sub-μs time resolutions with low gamma sensitivity of less than 10-12 and a rate capability on the order of Mcps (mega-counts-per-second). Here, we demonstrate the application of our detector to TOF-based techniques with examples of Bragg-edge transmission and neutron resonance transmission imaging (with computed tomography) carried out at J-PARC. We also consider the direct imaging of magnetic fields with our detector using polarized neutrons.

Research on correction algorithm of laser positioning system based on four quadrant detector

NASA Astrophysics Data System (ADS)

Gao, Qingsong; Meng, Xiangyong; Qian, Weixian; Cai, Guixia

2018-02-01

This paper first introduces the basic principle of the four quadrant detector, and a set of laser positioning experiment system is built based on the four quadrant detector. Four quadrant laser positioning system in the actual application, not only exist interference of background light and detector dark current noise, and the influence of random noise, system stability, spot equivalent error can't be ignored, so it is very important to system calibration and correction. This paper analyzes the various factors of system positioning error, and then propose an algorithm for correcting the system error, the results of simulation and experiment show that the modified algorithm can improve the effect of system error on positioning and improve the positioning accuracy.

3D modeling of electric fields in the LUX detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akerib, D. S.; Alsum, S.; Araújo, H. M.

This work details the development of a three-dimensional (3D) electric field model for the LUX detector. The detector took data to search for weakly interacting massive particles (WIMPs) during two periods. After the first period completed, a time-varying non-uniform negative charge developed in the polytetrafluoroethylene (PTFE) panels that define the radial boundary of the detector's active volume. This caused electric field variations in the detector in time, depth and azimuth, generating an electrostatic radially-inward force on electrons on their way upward to the liquid surface. To map this behavior, 3D electric field maps of the detector's active volume were generatedmore » on a monthly basis. This was done by fitting a model built in COMSOL Multiphysics to the uniformly distributed calibration data that were collected on a regular basis. The modeled average PTFE charge density increased over the course of the exposure from -3.6 to -5.5 μC/m 2. Here, from our studies, we deduce that the electric field magnitude varied locally while the mean value of the field of ~200 V/cm remained constant throughout the exposure. As a result of this work the varying electric fields and their impact on event reconstruction and discrimination were successfully modeled.« less

3D modeling of electric fields in the LUX detector

DOE PAGES

Akerib, D. S.; Alsum, S.; Araújo, H. M.; ...

2017-11-24

This work details the development of a three-dimensional (3D) electric field model for the LUX detector. The detector took data to search for weakly interacting massive particles (WIMPs) during two periods. After the first period completed, a time-varying non-uniform negative charge developed in the polytetrafluoroethylene (PTFE) panels that define the radial boundary of the detector's active volume. This caused electric field variations in the detector in time, depth and azimuth, generating an electrostatic radially-inward force on electrons on their way upward to the liquid surface. To map this behavior, 3D electric field maps of the detector's active volume were generatedmore » on a monthly basis. This was done by fitting a model built in COMSOL Multiphysics to the uniformly distributed calibration data that were collected on a regular basis. The modeled average PTFE charge density increased over the course of the exposure from -3.6 to -5.5 μC/m 2. Here, from our studies, we deduce that the electric field magnitude varied locally while the mean value of the field of ~200 V/cm remained constant throughout the exposure. As a result of this work the varying electric fields and their impact on event reconstruction and discrimination were successfully modeled.« less

3D modeling of electric fields in the LUX detector

NASA Astrophysics Data System (ADS)

Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Druszkiewicz, E.; Edwards, B. N.; Fallon, S. R.; Fan, A.; Fiorucci, S.; Gaitskell, R. J.; Genovesi, J.; Ghag, C.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Velan, V.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.

2017-11-01

This work details the development of a three-dimensional (3D) electric field model for the LUX detector. The detector took data to search for weakly interacting massive particles (WIMPs) during two periods. After the first period completed, a time-varying non-uniform negative charge developed in the polytetrafluoroethylene (PTFE) panels that define the radial boundary of the detector's active volume. This caused electric field variations in the detector in time, depth and azimuth, generating an electrostatic radially-inward force on electrons on their way upward to the liquid surface. To map this behavior, 3D electric field maps of the detector's active volume were generated on a monthly basis. This was done by fitting a model built in COMSOL Multiphysics to the uniformly distributed calibration data that were collected on a regular basis. The modeled average PTFE charge density increased over the course of the exposure from -3.6 to -5.5 μC/m2. From our studies, we deduce that the electric field magnitude varied locally while the mean value of the field of ~200 V/cm remained constant throughout the exposure. As a result of this work the varying electric fields and their impact on event reconstruction and discrimination were successfully modeled.

Mixed ionic-electronic conductor-based radiation detectors and methods of fabrication

DOEpatents

Conway, Adam; Beck, Patrick R; Graff, Robert T; Nelson, Art; Nikolic, Rebecca J; Payne, Stephen A; Voss, Lars; Kim, Hadong

2015-04-07

A method of fabricating a mixed ionic-electronic conductor (e.g. TlBr)-based radiation detector having halide-treated surfaces and associated methods of fabrication, which controls polarization of the mixed ionic-electronic MIEC material to improve stability and operational lifetime.

ZnO nanodisk based UV detectors with printed electrodes.

PubMed

Alenezi, Mohammad R; Alshammari, Abdullah S; Alzanki, Talal H; Jarowski, Peter; Henley, Simon John; Silva, S Ravi P

2014-04-08

The fabrication of highly functional materials for practical devices requires a deep understanding of the association between morphological and structural properties and applications. A controlled hydrothermal method to produce single crystal ZnO hexagonal nanodisks, nanorings, and nanoroses using a mixed solution of zinc sulfate (ZnSO4) and hexamethylenetetramine (HMTA) without the need of catalysts, substrates, or templates at low temperature (75 °C) is introduced. Metal-semiconductor-metal (MSM) ultraviolet (UV) detectors were fabricated based on individual and multiple single-crystal zinc oxide (ZnO) hexagonal nanodisks. High quality single crystal individual nanodisk devices were fabricated with inkjet-printed silver electrodes. The detectors fabricated show record photoresponsivity (3300 A/W) and external quantum efficiency (1.2 × 10(4)), which we attribute to the absence of grain boundaries in the single crystal ZnO nanodisk and the polarity of its exposed surface.

Safety Panel Resources

NASA Technical Reports Server (NTRS)

Stewart, Christine E.

2008-01-01

The goal of this paper is to explore what resources are potentially available to safety panels and to provide some guidance on how to utilize those resources. While the examples used in this paper will concentrate on the Flight Equipment and Reliability Review Panel (FESRRP) and Extravehicular Activity (EVA) hardware that have come through that panel, as well as resources at Johnson Space Center, the paper will address how this applies to safety panels in general, and where possible cite examples for other safety panels.

Quantifying spillover spreading for comparing instrument performance and aiding in multicolor panel design.

PubMed

Nguyen, Richard; Perfetto, Stephen; Mahnke, Yolanda D; Chattopadhyay, Pratip; Roederer, Mario

2013-03-01

After compensation, the measurement errors arising from multiple fluorescences spilling into each detector become evident by the spreading of nominally negative distributions. Depending on the instrument configuration and performance, and reagents used, this "spillover spreading" (SS) affects sensitivity in any given parameter. The degree of SS had been predicted theoretically to increase with measurement error, i.e., by the square root of fluorescence intensity, as well as directly related to the spectral overlap matrix coefficients. We devised a metric to quantify SS between any pair of detectors. This metric is intrinsic, as it is independent of fluorescence intensity. The combination of all such values for one instrument can be represented as a spillover spreading matrix (SSM). Single-stained controls were used to determine the SSM on multiple instruments over time, and under various conditions of signal quality. SSM values reveal fluorescence spectrum interactions that can limit the sensitivity of a reagent in the presence of brightly-stained cells on a different color. The SSM was found to be highly reproducible; its non-trivial values show a CV of less than 30% across a 2-month time frame. In addition, the SSM is comparable between similarly-configured instruments; instrument-specific differences in the SSM reveal underperforming detectors. Quantifying and monitoring the SSM can be a useful tool in instrument quality control to ensure consistent sensitivity and performance. In addition, the SSM is a key element for predicting the performance of multicolor immunofluorescence panels, which will aid in the optimization and development of new panels. We propose that the SSM is a critical component of QA/QC in evaluation of flow cytometer performance. Published 2013 Wiley Periodicals, Inc.

Photoacoustic tomography using a fiber based Fabry-Perot interferometer as an integrating line detector and image reconstruction by model-based time reversal method

NASA Astrophysics Data System (ADS)

Grün, H.; Paltauf, G.; Haltmeier, M.; Burgholzer, P.

2007-07-01

Photoacoustic imaging is based on the generation of acoustic waves in a semitransparent sample (e.g. soft tissue) after illumination with short pulses of light or radio waves. The goal is to recover the spatial distribution of absorbed energy density inside the sample from acoustic pressure signals measured outside the sample (photoacoustic inverse problem). If the acoustic pressure outside the illuminated sample is measured with a large-aperture detector, the signal at a certain time is given by an integral of the generated acoustic pressure distribution over an area that is determined by the shape of the detector. For example a planar detector measures the projections of the initial pressure distribution over planes parallel to the detector plane, which is the Radon transform of the initial pressure distribution. Stable and exact three-dimensional imaging with planar integrating detector requires measurements in all directions of space and so the receiver plane has to be rotated to cover the entire detection surface. We have recently presented a simpler set-up for exact imaging which requires only a single rotation axis and therefor the fragmentation of the area detector into line detectors perpendicular to the rotation axis. Using a two-dimensional reconstruction method and applying the inverse two-dimensional Radon transform afterwards gives an exact reconstruction of the three-dimensional sample with this set-up. In order to achieve high resolution, a fiber based Fabry-Perot interferometer is used. It is a single mode fiber with two fiber bragg gratings on both ends of the line detector. Thermal shifts and vibrations are compensated by frequency locking of the laser. The high resolution and the good performance of this integrating line detector has been demonstrated by photoacoustic measurements with line grid samples and phantoms using a model-based time reversal method for image reconstruction. The time reversed pressure field can be calculated directly by

Panel Board From Coconut Fibre And Pet Bottle

NASA Astrophysics Data System (ADS)

Ngadiman, Norhayati; Kaamin, Masiri; Abd. Kadir, Aslila; Sahat, Suhaila; Zaini, Aziza; Raihana Nor Zentan, Siti; Ain Ahmad, Nur; Amran, Wan Haizatul Aisyhah Wan

2018-03-01

The rate of global deforestation and its impact on the environment has led particle board manufacture to search for alternative feedstock, especially in countries where wood is less available compared to other cellulosic natural product. Based on the properties of coconut fibre and PET bottle, these two materials can be recycle as raw material for manufacture of panel board. As for this study, the coconut fibre were used as the filler and PET bottle as outer lining of the panel board. Two types of coconut fibre were used which are grinding and un-grinding coconut fibre. At first, the coconut fibre are undergoes softening, grinding, drying and sieving process, while PET bottle was cleaning, shredding, sieving before compacted using hydraulic hot press machine. There are four types of testing that been carried out which are swelling, water absorption, Modulus of Elasticity (MOE) and Modulus of Rupture (MOR). The result show the conventional board has the highest value for MOE test, so it's indicate that the conventional board is less strength from the coconut fibre board. As for water absorption test, the average water absorption of coconut fibre based panel board is less than conventional board. Overall, the coconut fibre board is better than conventional panel board because coconut fibre board are less swelling, has low water absorption, high modulus of rupture and low modulus of elasticity. Based on the finding, this coconut fibre panel board has potential as a stronger and long-lasting panel board than the conventional board in the market. Other than that, the panel also have their own aesthetic value since the recycled plastic bottle used as outer lining is colourful and giving aesthetic value.

A BPF-type algorithm for CT with a curved PI detector.

PubMed

Tang, Jie; Zhang, Li; Chen, Zhiqiang; Xing, Yuxiang; Cheng, Jianping

2006-08-21

Helical cone-beam CT is used widely nowadays because of its rapid scan speed and efficient utilization of x-ray dose. Recently, an exact reconstruction algorithm for helical cone-beam CT was proposed (Zou and Pan 2004a Phys. Med. Biol. 49 941-59). The algorithm is referred to as a backprojection-filtering (BPF) algorithm. This BPF algorithm for a helical cone-beam CT with a flat-panel detector (FPD-HCBCT) requires minimum data within the Tam-Danielsson window and can naturally address the problem of ROI reconstruction from data truncated in both longitudinal and transversal directions. In practical CT systems, detectors are expensive and always take a very important position in the total cost. Hence, we work on an exact reconstruction algorithm for a CT system with a detector of the smallest size, i.e., a curved PI detector fitting the Tam-Danielsson window. The reconstruction algorithm is derived following the framework of the BPF algorithm. Numerical simulations are done to validate our algorithm in this study.

Testing and evaluation of a slot and tab construction technique for light-weight wood-fiber-based structural panels under bending

Treesearch

Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

2015-01-01

This paper presented construction and strain distributions for light-weight wood-fiber-based structural panels with tri-grid core made from phenolic impregnated laminated paper composites under bending. A new fastening configuration of slots in the faces and tabs on the core was applied to the face/core interfaces of the sandwich panel in addition to epoxy resin. Both...

Rural Panel Surveys in Developing Countries: A Selective Review

PubMed Central

Hao, Lingxin; Wang, Weidong; Xie, Guihua

2017-01-01

Rural panel surveys are the most appropriate means to provide data for studying the unprecedented rapid migration and urbanization currently taking place in China and other developing countries. To maximize heterogeneity in urbanization and development over the last three decades, we selected rural panel surveys from five Asian countries, including India, Indonesia, Nepal, Thailand, and China. This paper provides a selective review, focusing on their panel survey methodology, which is organized based on our proposed four basics of panel surveys – representativeness, retrospect-prospect, multilevel tracking, and temporality. We analyzed the strengths and weaknesses of the selected panel surveys to provide directions for designing future rural panel studies in China and elsewhere in the developing world. PMID:29201494

Detective quantum efficiency of photon-counting x-ray detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanguay, Jesse, E-mail: jessetan@mail.ubc.ca; Yun, Seungman; Kim, Ho Kyung

Purpose: Single-photon-counting (SPC) x-ray imaging has the potential to improve image quality and enable novel energy-dependent imaging methods. Similar to conventional detectors, optimizing image SPC quality will require systems that produce the highest possible detective quantum efficiency (DQE). This paper builds on the cascaded-systems analysis (CSA) framework to develop a comprehensive description of the DQE of SPC detectors that implement adaptive binning. Methods: The DQE of SPC systems can be described using the CSA approach by propagating the probability density function (PDF) of the number of image-forming quanta through simple quantum processes. New relationships are developed to describe PDF transfermore » through serial and parallel cascades to accommodate scatter reabsorption. Results are applied to hypothetical silicon and selenium-based flat-panel SPC detectors including the effects of reabsorption of characteristic/scatter photons from photoelectric and Compton interactions, stochastic conversion of x-ray energy to secondary quanta, depth-dependent charge collection, and electronic noise. Results are compared with a Monte Carlo study. Results: Depth-dependent collection efficiency can result in substantial broadening of photopeaks that in turn may result in reduced DQE at lower x-ray energies (20–45 keV). Double-counting interaction events caused by reabsorption of characteristic/scatter photons may result in falsely inflated image signal-to-noise ratio and potential overestimation of the DQE. Conclusions: The CSA approach is extended to describe signal and noise propagation through photoelectric and Compton interactions in SPC detectors, including the effects of escape and reabsorption of emission/scatter photons. High-performance SPC systems can be achieved but only for certain combinations of secondary conversion gain, depth-dependent collection efficiency, electronic noise, and reabsorption characteristics.« less

Light redirecting system using sine-wave based panels for dense urban areas

NASA Astrophysics Data System (ADS)

Mohamed, Mohamed W. N.; Mashaly, Islam A.; Mohamed, Osama N.; El-Henawy, Sally I.; Galal, Ola; Taha, Iman; Nassar, Khaled; Safwat, Amr M. E.

2014-09-01

Cities and towns around the world are becoming more condensed due to the shrinking amount of buildable areas, which significantly reduces the amount of light that occupants have access to. This lack of natural lighting results in health, safety and quality of life degradation. This paper presents a new technique of transmitting sunlight downward into narrow alleys and streets, by using a daylighting guiding acrylic panel that is capable of changing the direction and distribution of the incident light. The core of the proposed daylight guidance system is made up of light transmission panels with high quality. The corrugations have sine wave shaped cross-section so that the panel functions as an optical diffuser perpendicular to the direction of sunlight propagation. The day lighting system consists of the corrugated panels and a lattice frame, which supports the panel. The proposed system is to be mounted on the building roof facing the sun so as to redirect the incident sunlight downward into the narrow alleys or streets. Since building sizes and orientations are different the frame is arranged such that substantially deep light penetration and high luminance level can be achieved. Simulation results show that the proposed panel improves the illuminance values by more than 200% and 400% in autumn and winter, respectively, provides fan-out angle that exceeds 80° for certain solar altitudes and the transmitted power percentage varies from 40% to 90% as the solar altitude varies from 10° to 80°. Experimental results are in a good agreement with the simulations.

Study on a novel panel support concept for radio telescopes with active surface

NASA Astrophysics Data System (ADS)

Yang, Dehua; Zhou, Guohua; Okoh, Daniel; Li, Guoping; Cheng, Jingquan

2010-07-01

Generally, panels of radio telescopes are mainly shaped in trapezoid and each is supported/positioned by four adjustors beneath its vertexes. Such configuration of panel supporting system is essentially hyper-static, and the panel is overconstrained from a kinematic point of view. When the panel is to be adjusted and/or actuated, it will suffer stress from its adjusters and hence its shape is to be distorted. This situation is not desirable for high precision panels, such as glass based panels especially used for sub-millimeter and shorter wavelength telescopes with active optics/active panel technology. This paper began with a general overview of panel patterns and panel supports of existing radio telescopes. Thereby, we proposed a preferable master-slave active surface concept for triangular and/or hexagonal panel pattern. In addition, we carry out panel error sensitivity analysis for all the 6 degrees of freedom (DOF) of a panel to identify what DOFs are most sensitive for an active surface. And afterwards, based on the error sensitivity analysis, we suggested an innovative parallel-series concept hexapod well fitted for an active panel to correct for all of its 6 rigid errors. A demonstration active surface using the master-slave concept and the hexapod manifested a great save in cost, where only 486 precision actuators are needed for 438 panels, which is 37% of those actuators needed by classic segmented mirror active optics. Further, we put forward a swaying-arm based design concept for the related connecting joints between panels, which ensures that all the panels attached on to it free from over-constraints when they are positioned and/or actuated. Principle and performance of the swaying-arm connecting mechanism are elaborated before a practical cablemesh based prototype active surface is presented with comprehensive finite element analysis and simulation.

Limits of a spatial resolution of the cascaded GEM based detectors

NASA Astrophysics Data System (ADS)

Kudryavtsev, V. N.; Maltsev, T. V.; Shekhtman, L. I.

2017-06-01

Spatial resolution of tracking detectors based on GEM cascades is determined in the simulation and measured. The simulation includes GEANT4 implemented transport of high energy electrons with careful accounting for atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing taking into account diffusion, gas amplification fluctuations, the distribution of signals over readout electrodes, electronics noise and particular algorithm of final coordinate calculation (centre-of-gravity algorithm). The simulation demonstrates that the minimum of the spatial resolution of about 10-20 μm can be achieved with a gas mixture of Ar-CO2 (75%-25%) at a strip pitch in the range from 250 μm to 300 μm. At a larger pitch the resolution quickly degrades reaching 70-100 μm at a pitch of 450-500 μm. The reasons of such behavior are discussed and corresponding hypothesis is tested. Particularly, the effect of electron cloud modification due to a GEM operation is considered using the ANSYS and Garfield++ simulation programs. The detection efficiency and spatial resolution of low-material triple-GEM detectors for the DEUTERON facility at BINP are measured at the extracted beam facility of the VEPP-4M collider. One-coordinate resolution of two detectors for the DEUTERON facility is measured with a 2 GeV electron beam. The determined values of the detectors' spatial resolution is equal to 46.6 ± 0.1 μm and 38.5 ± 0.2 μm for orthogonal tracks in two detectors, respectively.

[Analysis of the effect of detector's operating temperature on SNR in space-based remote sensor].

PubMed

Li, Zhan-feng; Wang, Shu-rong; Huang, Yu

2012-03-01

Limb viewing is a new viewing geometry for space-based atmospheric remote sensing, but the spectral radiance of atmosphere scattering reduces rapidly with limb height. So the signal-noise-ratio (SNR) is a key performance parameter of limb remote sensor. A SNR model varying with detector's temperature is proposed, based on analysis of spectral radiative transfer and noise' source in representative instruments. The SNR at limb height 70 km under space conditions was validated by simulation experiment on limb remote sensing spectrometer prototype. Theoretic analysis and experiment's results indicate congruously that when detector's temperature reduces to some extent, a maximum SNR will be reached. After considering the power consumption, thermal conductivity and other issues, optimal operating temperature of detector can be decided.

Absolute efficiency calibration of 6LiF-based solid state thermal neutron detectors

NASA Astrophysics Data System (ADS)

Finocchiaro, Paolo; Cosentino, Luigi; Lo Meo, Sergio; Nolte, Ralf; Radeck, Desiree

2018-03-01

The demand for new thermal neutron detectors as an alternative to 3He tubes in research, industrial, safety and homeland security applications, is growing. These needs have triggered research and development activities about new generations of thermal neutron detectors, characterized by reasonable efficiency and gamma rejection comparable to 3He tubes. In this paper we show the state of the art of a promising low-cost technique, based on commercial solid state silicon detectors coupled with thin neutron converter layers of 6LiF deposited onto carbon fiber substrates. A few configurations were studied with the GEANT4 simulation code, and the intrinsic efficiency of the corresponding detectors was calibrated at the PTB Thermal Neutron Calibration Facility. The results show that the measured intrinsic detection efficiency is well reproduced by the simulations, therefore validating the simulation tool in view of new designs. These neutron detectors have also been tested at neutron beam facilities like ISIS (Rutherford Appleton Laboratory, UK) and n_TOF (CERN) where a few samples are already in operation for beam flux and 2D profile measurements. Forthcoming applications are foreseen for the online monitoring of spent nuclear fuel casks in interim storage sites.

Multi-object detection and tracking technology based on hexagonal opto-electronic detector

NASA Astrophysics Data System (ADS)

Song, Yong; Hao, Qun; Li, Xiang

2008-02-01

A novel multi-object detection and tracking technology based on hexagonal opto-electronic detector is proposed, in which (1) a new hexagonal detector, which is composed of 6 linear CCDs, has been firstly developed to achieve the field of view of 360 degree, (2) to achieve the detection and tracking of multi-object with high speed, the object recognition criterions of Object Signal Width Criterion (OSWC) and Horizontal Scale Ratio Criterion (HSRC) are proposed. In this paper, Simulated Experiments have been carried out to verify the validity of the proposed technology, which show that the detection and tracking of multi-object can be achieved with high speed by using the proposed hexagonal detector and the criterions of OSWC and HSRC, indicating that the technology offers significant advantages in Photo-electric Detection, Computer Vision, Virtual Reality, Augment Reality, etc.

A New Targeted CFTR Mutation Panel Based on Next-Generation Sequencing Technology.

PubMed

Lucarelli, Marco; Porcaro, Luigi; Biffignandi, Alice; Costantino, Lucy; Giannone, Valentina; Alberti, Luisella; Bruno, Sabina Maria; Corbetta, Carlo; Torresani, Erminio; Colombo, Carla; Seia, Manuela

2017-09-01

Searching for mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) is a key step in the diagnosis of and neonatal and carrier screening for cystic fibrosis (CF), and it has implications for prognosis and personalized therapy. The large number of mutations and genetic and phenotypic variability make this search a complex task. Herein, we developed, validated, and tested a laboratory assay for an extended search for mutations in CFTR using a next-generation sequencing-based method, with a panel of 188 CFTR mutations customized for the Italian population. Overall, 1426 dried blood spots from neonatal screening, 402 genomic DNA samples from various origins, and 1138 genomic DNA samples from patients with CF were analyzed. The assay showed excellent analytical and diagnostic operative characteristics. We identified and experimentally validated 159 (of 188) CFTR mutations. The assay achieved detection rates of 95.0% and 95.6% in two large-scale case series of CF patients from central and northern Italy, respectively. These detection rates are among the highest reported so far with a genetic test for CF based on a mutation panel. This assay appears to be well suited for diagnostics, neonatal and carrier screening, and assisted reproduction, and it represents a considerable advantage in CF genetic counseling. Copyright © 2017 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Architectural Panels

NASA Technical Reports Server (NTRS)

1985-01-01

Alliance Wall Corporation's Whyteboard, a porcelain enamel on steel panels wall board, owes its color stability to a KIAC engineering background study to identify potential technologies and manufacturers of equipment which could be used to detect surface flaws. One result of the data base search was the purchase of a spectrocolorimeter which enables the company to control some 250 standard colors, and match special colors.

50. DETAIL OF TYPICAL PANELS IN ANALOG RECORD BAY. LEFT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

50. DETAIL OF TYPICAL PANELS IN ANALOG RECORD BAY. LEFT PANEL CONTAINS OSCILLOGRAPH AND CONTROLS. RIGHT PANEL CONTAINS CATHODE RAY TUBE AND INK-TYPE CHART RECORDER. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Family Medicine Panel Size with Care Teams: Impact on Quality.

PubMed

Angstman, Kurt B; Horn, Jennifer L; Bernard, Matthew E; Kresin, Molly M; Klavetter, Eric W; Maxson, Julie; Willis, Floyd B; Grover, Michael L; Bryan, Michael J; Thacher, Tom D

2016-01-01

The demand for comprehensive primary health care continues to expand. The development of team-based practice allows for improved capacity within a collective, collaborative environment. Our hypothesis was to determine the relationship between panel size and access, quality, patient satisfaction, and cost in a large family medicine group practice using a team-based care model. Data were retrospectively collected from 36 family physicians and included total panel size of patients, percentage of time spent on patient care, cost of care, access metrics, diabetic quality metrics, patient satisfaction surveys, and patient care complexity scores. We used linear regression analysis to assess the relationship between adjusted physician panel size, panel complexity, and outcomes. The third available appointments (P < .01) and diabetic quality (P = .03) were negatively affected by increased panel size. Patient satisfaction, cost, and percentage fill rate were not affected by panel size. A physician-adjusted panel size larger than the current mean (2959 patients) was associated with a greater likelihood of poor-quality rankings (≤25th percentile) compared with those with a less than average panel size (odds ratio [OR], 7.61; 95% confidence interval [CI], 1.13-51.46). Increased panel size was associated with a longer time to the third available appointment (OR, 10.9; 95% CI, 1.36-87.26) compared with physicians with panel sizes smaller than the mean. We demonstrated a negative impact of larger panel size on diabetic quality results and available appointment access. Evaluation of a family medicine practice parameters while controlling for panel size and patient complexity may help determine the optimal panel size for a practice. © Copyright 2016 by the American Board of Family Medicine.

Corrected Position Estimation in PET Detector Modules With Multi-Anode PMTs Using Neural Networks

NASA Astrophysics Data System (ADS)

Aliaga, R. J.; Martinez, J. D.; Gadea, R.; Sebastia, A.; Benlloch, J. M.; Sanchez, F.; Pavon, N.; Lerche, Ch.

2006-06-01

This paper studies the use of Neural Networks (NNs) for estimating the position of impinging photons in gamma ray detector modules for PET cameras based on continuous scintillators and Multi-Anode Photomultiplier Tubes (MA-PMTs). The detector under study is composed of a 49/spl times/49/spl times/10 mm/sup 3/ continuous slab of LSO coupled to a flat panel H8500 MA-PMT. Four digitized signals from a charge division circuit, which collects currents from the 8/spl times/8 anode matrix of the photomultiplier, are used as inputs to the NN, thus reducing drastically the number of electronic channels required. We have simulated the computation of the position for 511 keV gamma photons impacting perpendicularly to the detector surface. Thus, we have performed a thorough analysis of the NN architecture and training procedures in order to achieve the best results in terms of spatial resolution and bias correction. Results obtained using GEANT4 simulation toolkit show a resolution of 1.3 mm/1.9 mm FWHM at the center/edge of the detector and less than 1 mm of systematic error in the position near the edges of the scintillator. The results confirm that NNs can partially model and correct the non-uniform detector response using only the position-weighted signals from a simple 2D DPC circuit. Linearity degradation for oblique incidence is also investigated. Finally, the NN can be implemented in hardware for parallel real time corrected Line-of-Response (LOR) estimation. Results on resources occupancy and throughput in FPGA are presented.

An Adaptive Failure Detector Based on Quality of Service in Peer-to-Peer Networks

PubMed Central

Dong, Jian; Ren, Xiao; Zuo, Decheng; Liu, Hongwei

2014-01-01

The failure detector is one of the fundamental components that maintain high availability of Peer-to-Peer (P2P) networks. Under different network conditions, the adaptive failure detector based on quality of service (QoS) can achieve the detection time and accuracy required by upper applications with lower detection overhead. In P2P systems, complexity of network and high churn lead to high message loss rate. To reduce the impact on detection accuracy, baseline detection strategy based on retransmission mechanism has been employed widely in many P2P applications; however, Chen's classic adaptive model cannot describe this kind of detection strategy. In order to provide an efficient service of failure detection in P2P systems, this paper establishes a novel QoS evaluation model for the baseline detection strategy. The relationship between the detection period and the QoS is discussed and on this basis, an adaptive failure detector (B-AFD) is proposed, which can meet the quantitative QoS metrics under changing network environment. Meanwhile, it is observed from the experimental analysis that B-AFD achieves better detection accuracy and time with lower detection overhead compared to the traditional baseline strategy and the adaptive detectors based on Chen's model. Moreover, B-AFD has better adaptability to P2P network. PMID:25198005

Flat Panel Displays for Medical Monitoring Systems

DTIC Science & Technology

2001-10-25

filter prevents light from passing (figure 2). FLAT PANEL DISPLAYS FOR MEDICAL MONITORING SYSTEMS A. Cebrián, J. Millet , I. García Department of...The touch screen is placed over the flat panel display as a filter (figure 10) and allows user interfaces based in direct finger touch (figure 11

Quantitative kinetic analysis of lung nodules by temporal subtraction technique in dynamic chest radiography with a flat panel detector

NASA Astrophysics Data System (ADS)

Tsuchiya, Yuichiro; Kodera, Yoshie; Tanaka, Rie; Sanada, Shigeru

2007-03-01

Early detection and treatment of lung cancer is one of the most effective means to reduce cancer mortality; chest X-ray radiography has been widely used as a screening examination or health checkup. The new examination method and the development of computer analysis system allow obtaining respiratory kinetics by the use of flat panel detector (FPD), which is the expanded method of chest X-ray radiography. Through such changes functional evaluation of respiratory kinetics in chest has become available. Its introduction into clinical practice is expected in the future. In this study, we developed the computer analysis algorithm for the purpose of detecting lung nodules and evaluating quantitative kinetics. Breathing chest radiograph obtained by modified FPD was converted into 4 static images drawing the feature, by sequential temporal subtraction processing, morphologic enhancement processing, kinetic visualization processing, and lung region detection processing, after the breath synchronization process utilizing the diaphragmatic analysis of the vector movement. The artificial neural network used to analyze the density patterns detected the true nodules by analyzing these static images, and drew their kinetic tracks. For the algorithm performance and the evaluation of clinical effectiveness with 7 normal patients and simulated nodules, both showed sufficient detecting capability and kinetic imaging function without statistically significant difference. Our technique can quantitatively evaluate the kinetic range of nodules, and is effective in detecting a nodule on a breathing chest radiograph. Moreover, the application of this technique is expected to extend computer-aided diagnosis systems and facilitate the development of an automatic planning system for radiation therapy.

Data processing for soft X-ray diagnostics based on GEM detector measurements for fusion plasma imaging

NASA Astrophysics Data System (ADS)

Czarski, T.; Chernyshova, M.; Pozniak, K. T.; Kasprowicz, G.; Byszuk, A.; Juszczyk, B.; Wojenski, A.; Zabolotny, W.; Zienkiewicz, P.

2015-12-01

The measurement system based on GEM - Gas Electron Multiplier detector is developed for X-ray diagnostics of magnetic confinement fusion plasmas. The Triple Gas Electron Multiplier (T-GEM) is presented as soft X-ray (SXR) energy and position sensitive detector. The paper is focused on the measurement subject and describes the fundamental data processing to obtain reliable characteristics (histograms) useful for physicists. So, it is the software part of the project between the electronic hardware and physics applications. The project is original and it was developed by the paper authors. Multi-channel measurement system and essential data processing for X-ray energy and position recognition are considered. Several modes of data acquisition determined by hardware and software processing are introduced. Typical measuring issues are deliberated for the enhancement of data quality. The primary version based on 1-D GEM detector was applied for the high-resolution X-ray crystal spectrometer KX1 in the JET tokamak. The current version considers 2-D detector structures initially for the investigation purpose. Two detector structures with single-pixel sensors and multi-pixel (directional) sensors are considered for two-dimensional X-ray imaging. Fundamental output characteristics are presented for one and two dimensional detector structure. Representative results for reference source and tokamak plasma are demonstrated.

Reliability and Usefulness of Intraoperative 3-Dimensional Imaging by Mobile C-Arm With Flat-Panel Detector.

PubMed

Fujimori, Takahito; Iwasaki, Motoki; Nagamoto, Yukitaka; Kashii, Masafumi; Takao, Masaki; Sugiura, Tsuyoshi; Yoshikawa, Hideki

2017-02-01

Reliability and agreement study. To assess the reliability of intraoperative 3-dimensional imaging with a mobile C-arm (3D C-arm) equipped with a flat-panel detector. Pedicle screws are widely used in spinal surgery. Postoperative computed tomography (CT) is the most reliable method to detect screw misplacement. Recent advances in imaging devices have enabled surgeons to acquire 3D images of the spine during surgery. However, the reliability of these imaging devices is not known. A total of 203 screws were used in 22 consecutive patients who underwent surgery for scoliosis. Screw position was read twice with a 3D C-arm and twice with CT in a blinded manner by 2 independent observers. Screw positions were classified into 4 categories at every 2 mm and then into 2 simpler categories of acceptable or unacceptable. The degree of agreement with respect to screw positions between the double readings was evaluated by κ value. With unanimous agreement between 2 observers regarding postoperative CT readings considered the gold standard, the sensitivity of the 3D C-arm for determining screw misplacement was calculated. A total 804 readings were performed. For the 4-category classification, the mean κ value for the 2 interobserver readings was 0.52 for the 3D C-arm and 0.46 for CT. For the 2-category classification, the mean κ value for the 2 interobserver readings was 0.80 for the 3D C-arm and 0.66 for CT. The sensitivity, specificity, positive predictive value, and negative predictive value of intraoperative imaging with the 3D C-arm were 70%, 95%, 44%, and 98%, respectively. With respect to screws with perforation ≥4 mm, the sensitivity was 83%. No revision surgery was performed. Intraoperative imaging with a 3D C-arm was reliable for detecting screw misplacement and helpful in decreasing the rate of revision surgery for screw misplacement.

Advanced concentrator panels

NASA Technical Reports Server (NTRS)

Bell, D. M.; Bedard, R. J., Jr.

1981-01-01

The prototype fabrication of a lightweight, high-quality cellular glass substrate reflective panel for use in an advanced point-focusing solar concentrator was completed. The reflective panel is a gore shaped segment of an 11-m paraboloidal dish. The overall concentrator design and the design of the reflective panels are described. prototype-specific panel design modifications are discussed and the fabrication approach and procedure outlined.

Dual-wavelength light-emitting diode-based ultraviolet absorption detector for nano-flow capillary liquid chromatography.

PubMed

Xie, Xiaofeng; Tolley, Luke T; Truong, Thy X; Tolley, H Dennis; Farnsworth, Paul B; Lee, Milton L

2017-11-10

The design of a miniaturized LED-based UV-absorption detector was significantly improved for on-column nanoflow LC. The detector measures approximately 27mm×24mm×10mm and weighs only 30g. Detection limits down to the nanomolar range and linearity across 3 orders of magnitude were obtained using sodium anthraquinone-2-sulfonate as a test analyte. Using two miniaturized detectors, a dual-detector system was assembled containing 255nm and 275nm LEDs with only 216nL volume between the detectors A 100μm slit was used for on-column detection with a 150μm i.d. packed capillary column. Chromatographic separation of a phenol mixture was demonstrated using the dual-detector system, with each detector producing a unique chromatogram. Less than 6% variation in the ratios of absorbances measured at the two wavelengths for specific analytes was obtained across 3 orders of magnitude concentration, which demonstrates the potential of using absorption ratio measurements for target analyte detection. The dual-detector system was used for simple, but accurate, mobile phase flow rate measurement at the exit of the column. With a flow rate range from 200 to 2000nL/min, less than 3% variation was observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Graphene-based ultrasonic detector for photoacoustic imaging

NASA Astrophysics Data System (ADS)

Yang, Fan; Song, Wei; Zhang, Chonglei; Fang, Hui; Min, Changjun; Yuan, Xiaocong

2018-03-01

Taking advantage of optical absorption imaging contrast, photoacoustic imaging technology is able to map the volumetric distribution of the optical absorption properties within biological tissues. Unfortunately, traditional piezoceramics-based transducers used in most photoacoustic imaging setups have inadequate frequency response, resulting in both poor depth resolution and inaccurate quantification of the optical absorption information. Instead of the piezoelectric ultrasonic transducer, we develop a graphene-based optical sensor for detecting photoacoustic pressure. The refractive index in the coupling medium is modulated due to photoacoustic pressure perturbation, which creates the variation of the polarization-sensitive optical absorption property of the graphene. As a result, the photoacoustic detection is realized through recording the reflectance intensity difference of polarization light. The graphene-based detector process an estimated noise-equivalentpressure (NEP) sensitivity of 550 Pa over 20-MHz bandwidth with a nearby linear pressure response from 11.0 kPa to 53.0 kPa. Further, a graphene-based photoacoustic microscopy is built, and non-invasively reveals the microvascular anatomy in mouse ears label-freely.

The CosmicWatch Desktop Muon Detector: a self-contained, pocket sized particle detector

NASA Astrophysics Data System (ADS)

Axani, S. N.; Frankiewicz, K.; Conrad, J. M.

2018-03-01

The CosmicWatch Desktop Muon Detector is a self-contained, hand-held cosmic ray muon detector that is valuable for astro/particle physics research applications and outreach. The material cost of each detector is under 100 and it takes a novice student approximately four hours to build their first detector. The detectors are powered via a USB connection and the data can either be recorded directly to a computer or to a microSD card. Arduino- and Python-based software is provided to operate the detector and an online application to plot the data in real-time. In this paper, we describe the various design features, evaluate the performance, and illustrate the detectors capabilities by providing several example measurements.

Properties of GaAs:Cr-based Timepix detectors

NASA Astrophysics Data System (ADS)

Smolyanskiy, P.; Bergmann, B.; Chelkov, G.; Kotov, S.; Kruchonak, U.; Kozhevnikov, D.; Mora Sierra, Y.; Stekl, I.; Zhemchugov, A.

2018-02-01

The hybrid pixel detector technology brought to the X-ray imaging a low noise level at a high spatial resolution, thanks to the single photon counting. However, silicon as the most widespread detector material is marginally sensitive to photons with energies above 30 keV. Therefore, the high-Z alternatives to silicon such as gallium arsenide and cadmium telluride are increasingly attracting attention of the community for the development of X-ray imaging systems. The results of our investigations of the Timepix detectors bump bonded to sensors made of gallium arsenide compensated by chromium (GaAs:Cr) are presented in this work. The following properties are most important from the practical point of view: the IV characteristics, the charge transport characteristics, photon detection efficiency, operational stability, homogeneity, temperature dependence, as well as energy and spatial resolution are considered. The applicability of these detectors for spectroscopic X-ray imaging is discussed.

Segmented crystalline scintillators: empirical and theoretical investigation of a high quantum efficiency EPID based on an initial engineering prototype CsI(TI) detector.

PubMed

Sawant, Amit; Antonuk, Larry E; El-Mohri, Youcef; Zhao, Qihua; Wang, Yi; Li, Yixin; Du, Hong; Perna, Louis

2006-04-01

Modern-day radiotherapy relies on highly sophisticated forms of image guidance in order to implement increasingly conformal treatment plans and achieve precise dose delivery. One of the most important goals of such image guidance is to delineate the clinical target volume from surrounding normal tissue during patient setup and dose delivery, thereby avoiding dependence on surrogates such as bony landmarks. In order to achieve this goal, it is necessary to integrate highly efficient imaging technology, capable of resolving soft-tissue contrast at very low doses, within the treatment setup. In this paper we report on the development of one such modality, which comprises a nonoptimized, prototype electronic portal imaging device (EPID) based on a 40 mm thick, segmented crystalline CsI(Tl) detector incorporated into an indirect-detection active matrix flat panel imager (AMFPI). The segmented detector consists of a matrix of 160 x 160 optically isolated, crystalline CsI(Tl) elements spaced at 1016 microm pitch. The detector was coupled to an indirect detection-based active matrix array having a pixel pitch of 508 microm, with each detector element registered to 2 x 2 array pixels. The performance of the prototype imager was evaluated under very low-dose radiotherapy conditions and compared to that of a conventional megavoltage AMFPI based on a Lanex Fast-B phosphor screen. Detailed quantitative measurements were performed in order to determine the x-ray sensitivity, modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE). In addition, images of a contrast-detail phantom and an anthropomorphic head phantom were also acquired. The prototype imager exhibited approximately 22 times higher zero-frequency DQE (approximately 22%) compared to that of the conventional AMFPI (approximately 1%). The measured zero-frequency DQE was found to be lower than theoretical upper limits (approximately 27%) calculated from Monte Carlo simulations, which

Control device for automatic orientation of a solar panel based on a microcontroller (PIC16f628a)

NASA Astrophysics Data System (ADS)

Rezoug, M. R.; Krama, A.

2016-07-01

This work proposes a control device for autonomous solar tracker based on one axis, It consists of two main parts; the control part which is based on "the PIC16f628a"; it has the role of controlling, measuring and plotting responses. The second part is a mechanical device, which has the role of making the solar panel follows the day-night change of the sun throughout the year. Both parties are established to improve energy generation of the photovoltaic panels. In this paper, we will explain the main operating principles of our system. Also, we will provide experimental results which demonstrate the good performance and the efficiency of this system. This innovation is different from what has been proposed in previous studies. The important points of this system are maximum output energy and minimum energy consumption of solar tracker, its cost is relatively low with simplicity in implementation. The average power increase produced by using the tracking system for a particular day, is over 30 % compared with the static panel.

Critical Current Statistics of a Graphene-Based Josephson Junction Infrared Single Photon Detector

NASA Astrophysics Data System (ADS)

Walsh, Evan D.; Lee, Gil-Ho; Efetov, Dmitri K.; Heuck, Mikkel; Crossno, Jesse; Taniguchi, Takashi; Watanabe, Kenji; Ohki, Thomas A.; Kim, Philip; Englund, Dirk; Fong, Kin Chung

Graphene is a promising material for single photon detection due to its broadband absorption and exceptionally low specific heat. We present a photon detector using a graphene sheet as the weak link in a Josephson junction (JJ) to form a threshold detector for single infrared photons. Calculations show that such a device could experience temperature changes of a few hundred percent leading to sub-Hz dark count rates and internal efficiencies approaching unity. We have fabricated the graphene-based JJ (gJJ) detector and measure switching events that are consistent with single photon detection under illumination by an attenuated laser. We study the physical mechanism for these events through the critical current behavior of the gJJ as a function of incident photon flux.

Image-based Modeling of PSF Deformation with Application to Limited Angle PET Data

PubMed Central

Matej, Samuel; Li, Yusheng; Panetta, Joseph; Karp, Joel S.; Surti, Suleman

2016-01-01

The point-spread-functions (PSFs) of reconstructed images can be deformed due to detector effects such as resolution blurring and parallax error, data acquisition geometry such as insufficient sampling or limited angular coverage in dual-panel PET systems, or reconstruction imperfections/simplifications. PSF deformation decreases quantitative accuracy and its spatial variation lowers consistency of lesion uptake measurement across the imaging field-of-view (FOV). This can be a significant problem with dual panel PET systems even when using TOF data and image reconstruction models of the detector and data acquisition process. To correct for the spatially variant reconstructed PSF distortions we propose to use an image-based resolution model (IRM) that includes such image PSF deformation effects. Originally the IRM was mostly used for approximating data resolution effects of standard PET systems with full angular coverage in a computationally efficient way, but recently it was also used to mitigate effects of simplified geometric projectors. Our work goes beyond this by including into the IRM reconstruction imperfections caused by combination of the limited angle, parallax errors, and any other (residual) deformation effects and testing it for challenging dual panel data with strongly asymmetric and variable PSF deformations. We applied and tested these concepts using simulated data based on our design for a dedicated breast imaging geometry (B-PET) consisting of dual-panel, time-of-flight (TOF) detectors. We compared two image-based resolution models; i) a simple spatially invariant approximation to PSF deformation, which captures only the general PSF shape through an elongated 3D Gaussian function, and ii) a spatially variant model using a Gaussian mixture model (GMM) to more accurately capture the asymmetric PSF shape in images reconstructed from data acquired with the B-PET scanner geometry. Results demonstrate that while both IRMs decrease the overall uptake

Theoretical performance analysis for CMOS based high resolution detectors.

PubMed

Jain, Amit; Bednarek, Daniel R; Rudin, Stephen

2013-03-06

High resolution imaging capabilities are essential for accurately guiding successful endovascular interventional procedures. Present x-ray imaging detectors are not always adequate due to their inherent limitations. The newly-developed high-resolution micro-angiographic fluoroscope (MAF-CCD) detector has demonstrated excellent clinical image quality; however, further improvement in performance and physical design may be possible using CMOS sensors. We have thus calculated the theoretical performance of two proposed CMOS detectors which may be used as a successor to the MAF. The proposed detectors have a 300 μm thick HL-type CsI phosphor, a 50 μm-pixel CMOS sensor with and without a variable gain light image intensifier (LII), and are designated MAF-CMOS-LII and MAF-CMOS, respectively. For the performance evaluation, linear cascade modeling was used. The detector imaging chains were divided into individual stages characterized by one of the basic processes (quantum gain, binomial selection, stochastic and deterministic blurring, additive noise). Ranges of readout noise and exposure were used to calculate the detectors' MTF and DQE. The MAF-CMOS showed slightly better MTF than the MAF-CMOS-LII, but the MAF-CMOS-LII showed far better DQE, especially for lower exposures. The proposed detectors can have improved MTF and DQE compared with the present high resolution MAF detector. The performance of the MAF-CMOS is excellent for the angiography exposure range; however it is limited at fluoroscopic levels due to additive instrumentation noise. The MAF-CMOS-LII, having the advantage of the variable LII gain, can overcome the noise limitation and hence may perform exceptionally for the full range of required exposures; however, it is more complex and hence more expensive.

Tissue sensitive imaging and tomography without contrast agents for small animals with Timepix based detectors

NASA Astrophysics Data System (ADS)

Trojanova, E.; Schyns, L. E. J. R.; Dubois, L.; Jakubek, J.; Le Pape, A.; Sefc, L.; Sykora, V.; Turecek, D.; Uher, J.; Verhaegen, F.

2017-01-01

The tissue type resolving X-ray radiography and tomography can be performed even without contrast agents. The differences between soft tissue types such as kidney, muscles, fat, liver, brain and spleen were measured based on their spectral response. The Timepix based X-ray imaging detector WidePIX2×5 with 300 μm thick silicon sensors was used for most of the measurements presented in this work. These promising results are used for further optimizations of the detector technology and radiographic methods.

A novel high resolution, high sensitivity SPECT detector for molecular imaging of cardiovascular diseases

NASA Astrophysics Data System (ADS)

Cusanno, F.; Argentieri, A.; Baiocchi, M.; Colilli, S.; Cisbani, E.; De Vincentis, G.; Fratoni, R.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Lucentini, M.; Magliozzi, M. L.; Majewski, S.; Marano, G.; Musico, P.; Musumeci, M.; Santavenere, F.; Torrioli, S.; Tsui, B. M. W.; Vitelli, L.; Wang, Y.

2010-05-01

Cardiovascular diseases are the most common cause of death in western countries. Understanding the rupture of vulnerable atherosclerotic plaques and monitoring the effect of innovative therapies of heart failure is of fundamental importance. A flexible, high resolution, high sensitivity detector system for molecular imaging with radionuclides on small animal models has been designed for this aim. A prototype has been built using tungsten pinhole and LaBr3(Ce) scintillator coupled to Hamamatsu Flat Panel PMTs. Compact individual-channel readout has been designed, built and tested. Measurements with phantoms as well as pilot studies on mice have been performed, the results show that the myocardial perfusion in mice can be determined with sufficient precision. The detector will be improved replacing the Hamamatsu Flat Panel with Silicon Photomultipliers (SiPMs) to allow integration of the system with MRI scanners. Application of LaBr3(Ce) scintillator coupled to photosensor with high photon detection efficiency and excellent energy resolution will allow dual-label imaging to monitor simultaneously the cardiac perfusion and the molecular targets under investigation during the heart therapy.

A compact cosmic muon veto detector and possible use with the Iron Calorimeter detector for neutrinos

NASA Astrophysics Data System (ADS)

Panchal, N.; Mohanraj, S.; Kumar, A.; Dey, T.; Majumder, G.; Shinde, R.; Verma, P.; Satyanarayana, B.; Datar, V. M.

2017-11-01

The motivation for a cosmic muon veto (CMV) detector is to explore the possibility of locating the proposed large Iron Calorimeter (ICAL) detector at the India based Neutrino Observatory (INO) at a shallow depth. An initial effort in that direction, through the assembly and testing of a ~1 m × 1 m × 0.3 m plastic scintillator based detector, is described. The plan for making a CMV detector for a smaller prototype mini-ICAL is also outlined.

Test of a prototype neutron spectrometer based on diamond detectors in a fast reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osipenko, M.; Ripani, M.; Ricco, G.

2015-07-01

A prototype of neutron spectrometer based on diamond detectors has been developed. This prototype consists of a {sup 6}Li neutron converter sandwiched between two CVD diamond crystals. The radiation hardness of the diamond crystals makes it suitable for applications in low power research reactors, while a low sensitivity to gamma rays and low leakage current of the detector permit to reach good energy resolution. A fast coincidence between two crystals is used to reject background. The detector was read out using two different electronic chains connected to it by a few meters of cable. The first chain was based onmore » conventional charge-sensitive amplifiers, the other used a custom fast charge amplifier developed for this purpose. The prototype has been tested at various neutron sources and showed its practicability. In particular, the detector was calibrated in a TRIGA thermal reactor (LENA laboratory, University of Pavia) with neutron fluxes of 10{sup 8} n/cm{sup 2}s and at the 3 MeV D-D monochromatic neutron source named FNG (ENEA, Rome) with neutron fluxes of 10{sup 6} n/cm{sup 2}s. The neutron spectrum measurement was performed at the TAPIRO fast research reactor (ENEA, Casaccia) with fluxes of 10{sup 9} n/cm{sup 2}s. The obtained spectra were compared to Monte Carlo simulations, modeling detector response with MCNP and Geant4. (authors)« less

LYSO-based precision timing detectors with SiPM readout

NASA Astrophysics Data System (ADS)

Bornheim, A.; Hassanshahi, M. H.; Griffioen, M.; Mao, J.; Mangu, A.; Peña, C.; Spiropulu, M.; Xie, S.; Zhang, Z.

2018-07-01

Particle detectors based on scintillation light are particularly well suited for precision timing applications with resolutions of a few 10's of ps. The large primary signal and the initial rise time of the scintillation light result in very favorable signal-to-noise conditions with fast signals. In this paper we describe timing studies using a LYSO-based sampling calorimeter with wavelength-shifting capillary light extraction and silicon photomultipliers as photosensors. We study the contributions of various steps of the signal generation to the total time resolution, and demonstrate its feasibility as a radiation-hard technology for calorimeters at high intensity hadron colliders.

Hybrid organic/inorganic position-sensitive detectors based on PEDOT:PSS/n-Si

NASA Astrophysics Data System (ADS)

Javadi, Mohammad; Gholami, Mahdiyeh; Torbatiyan, Hadis; Abdi, Yaser

2018-03-01

Various configurations like p-n junctions, metal-semiconductor Schottky barriers, and metal-oxide-semiconductor structures have been widely used in position-sensitive detectors. In this report, we propose a PEDOT:PSS/n-Si heterojunction as a hybrid organic/inorganic configuration for position-sensitive detectors. The influence of the thickness of the PEDOT:PSS layer, the wavelength of incident light, and the intensity of illumination on the device performance are investigated. The hybrid PSD exhibits very high sensitivity (>100 mV/mm), excellent nonlinearity (<3%), and a response correlation coefficient (>0.995) with a response time of <4 ms to the inhomogeneous IR illumination. The presented hybrid configuration also benefits from a straightforward low-temperature fabrication process. These advantages of the PEDOT:PSS/n-Si heterojunction are very promising for developing a new class of position-sensitive detectors based on the hybrid organic/inorganic junctions.

Study of a nTHGEM-based thermal neutron detector

NASA Astrophysics Data System (ADS)

Li, Ke; Zhou, Jian-Rong; Wang, Xiao-Dong; Xiong, Tao; Zhang, Ying; Xie, Yu-Guang; Zhou, Liang; Xu, Hong; Yang, Gui-An; Wang, Yan-Feng; Wang, Yan; Wu, Jin-Jie; Sun, Zhi-Jia; Hu, Bi-Tao

2016-07-01

With new generation neutron sources, traditional neutron detectors cannot satisfy the demands of the applications, especially under high flux. Furthermore, facing the global crisis in 3He gas supply, research on new types of neutron detector as an alternative to 3He is a research hotspot in the field of particle detection. GEM (Gaseous Electron Multiplier) neutron detectors have high counting rate, good spatial and time resolution, and could be one future direction of the development of neutron detectors. In this paper, the physical process of neutron detection is simulated with Geant4 code, studying the relations between thermal conversion efficiency, boron thickness and number of boron layers. Due to the special characteristics of neutron detection, we have developed a novel type of special ceramic nTHGEM (neutron THick GEM) for neutron detection. The performance of the nTHGEM working in different Ar/CO2 mixtures is presented, including measurements of the gain and the count rate plateau using a copper target X-ray source. A detector with a single nTHGEM has been tested for 2-D imaging using a 252Cf neutron source. The key parameters of the performance of the nTHGEM detector have been obtained, providing necessary experimental data as a reference for further research on this detector. Supported by National Natural Science Foundation of China (11127508, 11175199, 11205253, 11405191), Key Laboratory of Neutron Physics, CAEP (2013DB06, 2013BB04) and CAS (YZ201512)

Evolution of Some Particle Detectors Based On the Discharge in Gases

DOE R&D Accomplishments Database

Charpak, G.

1969-11-19

Summary of the properties of some of the detectors that are commonly used in counter experiments to localize charged particles, and which are based on discharge in gases under the influence of electric fields and some basic facts of gaseous amplification in homogeneous and inhomogeneous fields.

High temperature structural sandwich panels

NASA Astrophysics Data System (ADS)

Papakonstantinou, Christos G.

High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

Laser positioning of four-quadrant detector based on pseudo-random sequence

NASA Astrophysics Data System (ADS)

Tang, Yanqin; Cao, Ercong; Hu, Xiaobo; Gu, Guohua; Qian, Weixian

2016-10-01

Nowadays the technology of laser positioning based on four-quadrant detector has the wide scope of the study and application areas. The main principle of laser positioning is that by capturing the projection of the laser spot on the photosensitive surface of the detector, and then calculating the output signal from the detector to obtain the coordinates of the spot on the photosensitive surface of the detector, the coordinate information of the laser spot in the space with respect to detector system which reflects the spatial position of the target object is calculated effectively. Given the extensive application of FPGA technology and the pseudo-random sequence has the similar correlation of white noise, the measurement process of the interference, noise has little effect on the correlation peak. In order to improve anti-jamming capability of the guided missile in tracking process, when the laser pulse emission, the laser pulse period is pseudo-random encoded which maintains in the range of 40ms-65ms so that people of interfering can't find the exact real laser pulse. Also, because the receiver knows the way to solve the pseudo-random code, when the receiver receives two consecutive laser pulses, the laser pulse period can be decoded successfully. In the FPGA hardware implementation process, around each laser pulse arrival time, the receiver can open a wave door to get location information contained the true signal. Taking into account the first two consecutive pulses received have been disturbed, so after receiving the first laser pulse, it receives all the laser pulse in the next 40ms-65ms to obtain the corresponding pseudo-random code.

Effect of Clouds on Apertures of Space-based Air Fluorescence Detectors

NASA Technical Reports Server (NTRS)

Sokolsky, P.; Krizmanic, J.

2003-01-01

Space-based ultra-high-energy cosmic ray detectors observe fluorescence light from extensive air showers produced by these particles in the troposphere. Clouds can scatter and absorb this light and produce systematic errors in energy determination and spectrum normalization. We study the possibility of using IR remote sensing data from MODIS and GOES satellites to delimit clear areas of the atmosphere. The efficiency for detecting ultra-high-energy cosmic rays whose showers do not intersect clouds is determined for real, night-time cloud scenes. We use the MODIS SST cloud mask product to define clear pixels for cloud scenes along the equator and use the OWL Monte Carlo to generate showers in the cloud scenes. We find the efficiency for cloud-free showers with closest approach of three pixels to a cloudy pixel is 6.5% exclusive of other factors. We conclude that defining a totally cloud-free aperture reduces the sensitivity of space-based fluorescence detectors to unacceptably small levels.

Neutron diffraction measurements on a reference metallic sample with a high-efficiency GEM side-on 10B-based thermal neutron detector

NASA Astrophysics Data System (ADS)

Pietropaolo, A.; Claps, G.; Fedrigo, A.; Grazzi, F.; Höglund, C.; Murtas, F.; Scherillo, A.; Schmidt, S.; Schooneveld, E. M.

2018-03-01

The upgraded version of the GEM side-on thermal neutron detector was successfully tested in a neutron diffraction experiment on a reference sample using the INES diffractometer at the ISIS spallation neutron source, UK. The performance of the new 10B4C-based detector is compared to that of a standard 3He tube, operating at the instrument as a part of the detectors assembly. The results show that the upgraded detector has a better resolution and an efficiency of the same order of magnitude of a 3He-based detector.

Carbon emissions, logistics volume and GDP in China: empirical analysis based on panel data model.

PubMed

Guo, Xiaopeng; Ren, Dongfang; Shi, Jiaxing

2016-12-01

This paper studies the relationship among carbon emissions, GDP, and logistics by using a panel data model and a combination of statistics and econometrics theory. The model is based on the historical data of 10 typical provinces and cities in China during 2005-2014. The model in this paper adds the variability of logistics on the basis of previous studies, and this variable is replaced by the freight turnover of the provinces. Carbon emissions are calculated by using the annual consumption of coal, oil, and natural gas. GDP is the gross domestic product. The results showed that the amount of logistics and GDP have a contribution to carbon emissions and the long-term relationships are different between different cities in China, mainly influenced by the difference among development mode, economic structure, and level of logistic development. After the testing of panel model setting, this paper established a variable coefficient model of the panel. The influence of GDP and logistics on carbon emissions is obtained according to the influence factors among the variables. The paper concludes with main findings and provides recommendations toward rational planning of urban sustainable development and environmental protection for China.

NOTE: A BPF-type algorithm for CT with a curved PI detector

NASA Astrophysics Data System (ADS)

Tang, Jie; Zhang, Li; Chen, Zhiqiang; Xing, Yuxiang; Cheng, Jianping

2006-08-01

Helical cone-beam CT is used widely nowadays because of its rapid scan speed and efficient utilization of x-ray dose. Recently, an exact reconstruction algorithm for helical cone-beam CT was proposed (Zou and Pan 2004a Phys. Med. Biol. 49 941 59). The algorithm is referred to as a backprojection-filtering (BPF) algorithm. This BPF algorithm for a helical cone-beam CT with a flat-panel detector (FPD-HCBCT) requires minimum data within the Tam Danielsson window and can naturally address the problem of ROI reconstruction from data truncated in both longitudinal and transversal directions. In practical CT systems, detectors are expensive and always take a very important position in the total cost. Hence, we work on an exact reconstruction algorithm for a CT system with a detector of the smallest size, i.e., a curved PI detector fitting the Tam Danielsson window. The reconstruction algorithm is derived following the framework of the BPF algorithm. Numerical simulations are done to validate our algorithm in this study.

Modeling Microalgae Productivity in Industrial-Scale Vertical Flat Panel Photobioreactors.

PubMed

Endres, Christian H; Roth, Arne; Brück, Thomas B

2018-05-01

Potentially achievable biomass yields are a decisive performance indicator for the economic viability of mass cultivation of microalgae. In this study, a computer model has been developed and applied to estimate the productivity of microalgae for large-scale outdoor cultivation in vertical flat panel photobioreactors. Algae growth is determined based on simulations of the reactor temperature and light distribution. Site-specific weather and irradiation data are used for annual yield estimations in six climate zones. Shading and reflections between opposing panels and between panels and the ground are dynamically computed based on the reactor geometry and the position of the sun. The results indicate that thin panels (≤0.05 m) are best suited for the assumed cell density of 2 g L -1 and that reactor panels should face in north-south direction. Panel spacings of 0.4-0.75 m at a panel height of 1 m appear most suitable for commercial applications. Under these preconditions, yields of around 10 kg m -2 a -1 are possible for most locations in the U.S. Only in hot climates significantly lower yields have to be expected, as extreme reactor temperatures limit overall productivity.

Photodetection Characterization of SiPM Technologies for their Application in Scintillator based Neutron Detectors

NASA Astrophysics Data System (ADS)

Kumar, S.; Durini, D.; Degenhardt, C.; van Waasen, S.

2018-01-01

Small-angle neutron scattering (SANS) experiments have become one of the most important techniques in the investigation of the properties of material on the atomic scale. Until 2001, nearly exclusively 3He-based detectors were used for neutron detection in these experiments, but due to the scarcity of 3He and its steeply rising price, researchers started to look for suitable alternatives. Scintillation based solid state detectors appeared as a prominent alternative. Silicon photomultipliers (SiPM), having single photon resolution, lower bias voltages compared to photomultiplier tubes (PMT), insensitivity to magnetic fields, low cost, possibility of modular design and higher readout rates, have the potential of becoming a photon detector of choice in scintillator based neutron detectors. The major concerns for utilizing the SiPM technology in this kind of applications are the increase in their noise performance and the decrease in their photon detection efficiency (PDE) due to direct exposure to neutrons. Here, a detailed comparative analysis of the PDE performance in the range between UV and NIR parts of the spectra for three different SiPM technologies, before and after irradiation with cold neutrons, has been carried out. For this investigation, one digital and two analog SiPM arrays were irradiated with 5Å wavelength cold neutrons and up to a dose of 6×1012 n/cm2 at the KWS-1 instrument of the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany.

UBO Detector - A cluster-based, fully automated pipeline for extracting white matter hyperintensities.

PubMed

Jiang, Jiyang; Liu, Tao; Zhu, Wanlin; Koncz, Rebecca; Liu, Hao; Lee, Teresa; Sachdev, Perminder S; Wen, Wei

2018-07-01

We present 'UBO Detector', a cluster-based, fully automated pipeline for extracting and calculating variables for regions of white matter hyperintensities (WMH) (available for download at https://cheba.unsw.edu.au/group/neuroimaging-pipeline). It takes T1-weighted and fluid attenuated inversion recovery (FLAIR) scans as input, and SPM12 and FSL functions are utilised for pre-processing. The candidate clusters are then generated by FMRIB's Automated Segmentation Tool (FAST). A supervised machine learning algorithm, k-nearest neighbor (k-NN), is applied to determine whether the candidate clusters are WMH or non-WMH. UBO Detector generates both image and text (volumes and the number of WMH clusters) outputs for whole brain, periventricular, deep, and lobar WMH, as well as WMH in arterial territories. The computation time for each brain is approximately 15 min. We validated the performance of UBO Detector by showing a) high segmentation (similarity index (SI) = 0.848) and volumetric (intraclass correlation coefficient (ICC) = 0.985) agreement between the UBO Detector-derived and manually traced WMH; b) highly correlated (r 2  > 0.9) and a steady increase of WMH volumes over time; and c) significant associations of periventricular (t = 22.591, p < 0.001) and deep (t = 14.523, p < 0.001) WMH volumes generated by UBO Detector with Fazekas rating scores. With parallel computing enabled in UBO Detector, the processing can take advantage of multi-core CPU's that are commonly available on workstations. In conclusion, UBO Detector is a reliable, efficient and fully automated WMH segmentation pipeline. Copyright © 2018 Elsevier Inc. All rights reserved.

Predictable quantum efficient detector based on n-type silicon photodiodes

NASA Astrophysics Data System (ADS)

Dönsberg, Timo; Manoocheri, Farshid; Sildoja, Meelis; Juntunen, Mikko; Savin, Hele; Tuovinen, Esa; Ronkainen, Hannu; Prunnila, Mika; Merimaa, Mikko; Tang, Chi Kwong; Gran, Jarle; Müller, Ingmar; Werner, Lutz; Rougié, Bernard; Pons, Alicia; Smîd, Marek; Gál, Péter; Lolli, Lapo; Brida, Giorgio; Rastello, Maria Luisa; Ikonen, Erkki

2017-12-01

The predictable quantum efficient detector (PQED) consists of two custom-made induced junction photodiodes that are mounted in a wedged trap configuration for the reduction of reflectance losses. Until now, all manufactured PQED photodiodes have been based on a structure where a SiO2 layer is thermally grown on top of p-type silicon substrate. In this paper, we present the design, manufacturing, modelling and characterization of a new type of PQED, where the photodiodes have an Al2O3 layer on top of n-type silicon substrate. Atomic layer deposition is used to deposit the layer to the desired thickness. Two sets of photodiodes with varying oxide thicknesses and substrate doping concentrations were fabricated. In order to predict recombination losses of charge carriers, a 3D model of the photodiode was built into Cogenda Genius semiconductor simulation software. It is important to note that a novel experimental method was developed to obtain values for the 3D model parameters. This makes the prediction of the PQED responsivity a completely autonomous process. Detectors were characterized for temperature dependence of dark current, spatial uniformity of responsivity, reflectance, linearity and absolute responsivity at the wavelengths of 488 nm and 532 nm. For both sets of photodiodes, the modelled and measured responsivities were generally in agreement within the measurement and modelling uncertainties of around 100 parts per million (ppm). There is, however, an indication that the modelled internal quantum deficiency may be underestimated by a similar amount. Moreover, the responsivities of the detectors were spatially uniform within 30 ppm peak-to-peak variation. The results obtained in this research indicate that the n-type induced junction photodiode is a very promising alternative to the existing p-type detectors, and thus give additional credibility to the concept of modelled quantum detector serving as a primary standard. Furthermore, the manufacturing of

Panel positioning error and support mechanism for a 30-m THz radio telescope

NASA Astrophysics Data System (ADS)

Yang, De-Hua; Okoh, Daniel; Zhou, Guo-Hua; Li, Ai-Hua; Li, Guo-Ping; Cheng, Jing-Quan

2011-06-01

A 30-m TeraHertz (THz) radio telescope is proposed to operate at 200 μm with an active primary surface. This paper presents sensitivity analysis of active surface panel positioning errors with optical performance in terms of the Strehl ratio. Based on Ruze's surface error theory and using a Monte Carlo simulation, the effects of six rigid panel positioning errors, such as piston, tip, tilt, radial, azimuthal and twist displacements, were directly derived. The optical performance of the telescope was then evaluated using the standard Strehl ratio. We graphically illustrated the various panel error effects by presenting simulations of complete ensembles of full reflector surface errors for the six different rigid panel positioning errors. Study of the panel error sensitivity analysis revealed that the piston error and tilt/tip errors are dominant while the other rigid errors are much less important. Furthermore, as indicated by the results, we conceived of an alternative Master-Slave Concept-based (MSC-based) active surface by implementating a special Series-Parallel Concept-based (SPC-based) hexapod as the active panel support mechanism. A new 30-m active reflector based on the two concepts was demonstrated to achieve correction for all the six rigid panel positioning errors in an economically feasible way.

Performance of a SiPM based semi-monolithic scintillator PET detector.

PubMed

Zhang, Xianming; Wang, Xiaohui; Ren, Ning; Kuang, Zhonghua; Deng, Xinhan; Fu, Xin; Wu, San; Sang, Ziru; Hu, Zhanli; Liang, Dong; Liu, Xin; Zheng, Hairong; Yang, Yongfeng

2017-09-21

A depth encoding PET detector module using semi-monolithic scintillation crystal single-ended readout by a SiPM array was built and its performance was measured. The semi-monolithic scintillator detector consists of 11 polished LYSO slices measuring 1  ×  11.6  ×  10 mm 3 . The slices are glued together with enhanced specular reflector (ESR) in between and outside of the slices. The bottom surface of the slices is coupled to a 4  ×  4 SiPM array with a 1 mm light guide and silicon grease between them. No reflector is used on the top surface and two sides of the slices to reduce the scintillation photon reflection. The signals of the 4  ×  4 SiPM array are grouped along rows and columns separately into eight signals. Four SiPM column signals are used to identify the slices according to the center of the gravity of the scintillation photon distribution in the pixelated direction. Four SiPM row signals are used to estimate the y (monolithic direction) and z (depth of interaction) positions according to the center of the gravity and the width of the scintillation photon distribution in the monolithic direction, respectively. The detector was measured with 1 mm sampling interval in both the y and z directions with electronic collimation by using a 0.25 mm diameter 22 Na point source and a 1  ×  1  ×  20 mm 3 LYSO crystal detector. An average slice based energy resolution of 14.9% was obtained. All slices of 1 mm thick were clearly resolved and a detector with even thinner slices could be used. The y positions calculated with the center of gravity method are different for interactions happening at the same y, but different z positions due to depth dependent edge effects. The least-square minimization and the maximum likelihood positioning algorithms were developed and both methods improved the spatial resolution at the edges of the detector as compared with the center of gravity method. A mean absolute

Performance of a SiPM based semi-monolithic scintillator PET detector

NASA Astrophysics Data System (ADS)

Zhang, Xianming; Wang, Xiaohui; Ren, Ning; Kuang, Zhonghua; Deng, Xinhan; Fu, Xin; Wu, San; Sang, Ziru; Hu, Zhanli; Liang, Dong; Liu, Xin; Zheng, Hairong; Yang, Yongfeng

2017-10-01

A depth encoding PET detector module using semi-monolithic scintillation crystal single-ended readout by a SiPM array was built and its performance was measured. The semi-monolithic scintillator detector consists of 11 polished LYSO slices measuring 1  ×  11.6  ×  10 mm3. The slices are glued together with enhanced specular reflector (ESR) in between and outside of the slices. The bottom surface of the slices is coupled to a 4  ×  4 SiPM array with a 1 mm light guide and silicon grease between them. No reflector is used on the top surface and two sides of the slices to reduce the scintillation photon reflection. The signals of the 4  ×  4 SiPM array are grouped along rows and columns separately into eight signals. Four SiPM column signals are used to identify the slices according to the center of the gravity of the scintillation photon distribution in the pixelated direction. Four SiPM row signals are used to estimate the y (monolithic direction) and z (depth of interaction) positions according to the center of the gravity and the width of the scintillation photon distribution in the monolithic direction, respectively. The detector was measured with 1 mm sampling interval in both the y and z directions with electronic collimation by using a 0.25 mm diameter 22Na point source and a 1  ×  1  ×  20 mm3 LYSO crystal detector. An average slice based energy resolution of 14.9% was obtained. All slices of 1 mm thick were clearly resolved and a detector with even thinner slices could be used. The y positions calculated with the center of gravity method are different for interactions happening at the same y, but different z positions due to depth dependent edge effects. The least-square minimization and the maximum likelihood positioning algorithms were developed and both methods improved the spatial resolution at the edges of the detector as compared with the center of gravity method. A mean absolute error

Evaluation of a GEM and CAT-based detector for radiation therapy beam monitoring

NASA Astrophysics Data System (ADS)

Brahme, A.; Danielsson, M.; Iacobaeus, C.; Ostling, J.; Peskov, V.; Wallmark, M.

2000-11-01

We are developing a radiation therapy beam monitor for the Karolinska Institute. This monitor will consist of two consecutive detectors confined in one gas chamber: a "keV-photon detector", which will allow diagnostic quality visualization of the patient, and a "MeV-photon detector", that will measure the absolute intensity of the therapy beam and its position with respect to the patient. Both detectors are based on highly radiation resistant gas and solid photon to electron converters, combined with GEMs and a CAT as amplification structures. We have performed systematic studies of the high-rate characteristics of the GEM and the CAT, as well as tested the electron transfer through these electron multipliers and various types of converters. The tests show that the GEM and the CAT satisfy all requirements for the beam monitoring system. As a result of these studies we successfully developed and tested a full section of the beam monitor equipped with a MeV-photon converter placed between the GEM and the CAT.

Superlinear threshold detectors in quantum cryptography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lydersen, Lars; Maroey, Oystein; Skaar, Johannes

2011-09-15

We introduce the concept of a superlinear threshold detector, a detector that has a higher probability to detect multiple photons if it receives them simultaneously rather than at separate times. Highly superlinear threshold detectors in quantum key distribution systems allow eavesdropping the full secret key without being revealed. Here, we generalize the detector control attack, and analyze how it performs against quantum key distribution systems with moderately superlinear detectors. We quantify the superlinearity in superconducting single-photon detectors based on earlier published data, and gated avalanche photodiode detectors based on our own measurements. The analysis shows that quantum key distribution systemsmore » using detector(s) of either type can be vulnerable to eavesdropping. The avalanche photodiode detector becomes superlinear toward the end of the gate. For systems expecting substantial loss, or for systems not monitoring loss, this would allow eavesdropping using trigger pulses containing less than 120 photons per pulse. Such an attack would be virtually impossible to catch with an optical power meter at the receiver entrance.« less

PANEL LIBRARY AND EDITOR

NASA Technical Reports Server (NTRS)

Raible, E.

1994-01-01

The Panel Library and Editor is a graphical user interface (GUI) builder for the Silicon Graphics IRIS workstation family. The toolkit creates "widgets" which can be manipulated by the user. Its appearance is similar to that of the X-Windows System. The Panel Library is written in C and is used by programmers writing user-friendly mouse-driven applications for the IRIS. GUIs built using the Panel Library consist of "actuators" and "panels." Actuators are buttons, dials, sliders, or other mouse-driven symbols. Panels are groups of actuators that occupy separate windows on the IRIS workstation. The application user can alter variables in the graphics program, or fire off functions with a click on a button. The evolution of data values can be tracked with meters and strip charts, and dialog boxes with text processing can be built. Panels can be stored as icons when not in use. The Panel Editor is a program used to interactively create and test panel library interfaces in a simple and efficient way. The Panel Editor itself uses a panel library interface, so all actions are mouse driven. Extensive context-sensitive on-line help is provided. Programmers can graphically create and test the user interface without writing a single line of code. Once an interface is judged satisfactory, the Panel Editor will dump it out as a file of C code that can be used in an application. The Panel Library (v9.8) and Editor (v1.1) are written in C-Language (63%) and Scheme, a dialect of LISP, (37%) for Silicon Graphics 4D series workstations running IRIX 3.2 or higher. Approximately 10Mb of disk space is required once compiled. 1.5Mb of main memory is required to execute the panel editor. This program is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format for an IRIS, and includes a copy of XScheme, the public-domain Scheme interpreter used by the Panel Editor. The Panel Library Programmer's Manual is included on the distribution media. The Panel Library and

Development of a circular shape Si-PM-based detector ring for breast-dedicated PET system

NASA Astrophysics Data System (ADS)

Nakanishi, Kouhei; Yamamoto, Seiichi; Watabe, Hiroshi; Abe, Shinji; Fujita, Naotoshi; Kato, Katsuhiko

2018-02-01

In clinical situations, various breast-dedicated positron emission tomography (PET) systems have been used. However, clinical breast-dedicated PET systems have polygonal detector ring. Polygonal detector ring sometimes causes image artifact, so complicated reconstruction algorithm is needed to reduce artifact. Consequently, we developed a circular detector ring for breast-dedicated PET to obtain images without artifact using a simple reconstruction algorithm. We used Lu1.9Gd0.1SiO5 (LGSO) scintillator block which was made of 1.5 x 1.9 x 15 mm pixels that were arranged in an 8 x 24 matrix. As photodetectors, we used silicon photomultiplier (Si-PM) arrays whose channel size was 3 x 3 mm. A detector unit was composed of four scintillator blocks, 16 Si-PM arrays and a light guide. The developed detector unit had angled configuration since the light guide was bending. A detector unit had three gaps with an angle of 5.625° between scintillator blocks. With these configurations, we could arrange 64 scintillator blocks in nearly circular shape (regular 64-sided polygon) using 16 detector units. The use of the smaller number of detector units could reduce the size of the front-end electronics circuits. The inner diameter of the developed detector ring was 260 mm. This size was similar to those of brain PET systems, so our breast-dedicated PET detector ring can measure not only breast but also brain. Measured radial, tangential and axial spatial resolution of the detector ring reconstructed by the filtered back-projection (FBP) algorithm were 2.1 mm FWHM, 2.0 mm FWHM and 1.7 mm FWHM at center of field of view (FOV), respectively. The sensitivity was 2.0% at center of the axial FOV. With the developed detector ring, we could obtain high resolution image of the breast phantom and the brain phantom. We conclude that our developed Si-PM-based detector ring is promising for a high resolution breast-dedicated PET system that can also be used for brain PET system.

Panel-based NGS Reveals Novel Pathogenic Mutations in Autosomal Recessive Retinitis Pigmentosa

PubMed Central

Perez-Carro, Raquel; Corton, Marta; Sánchez-Navarro, Iker; Zurita, Olga; Sanchez-Bolivar, Noelia; Sánchez-Alcudia, Rocío; Lelieveld, Stefan H.; Aller, Elena; Lopez-Martinez, Miguel Angel; López-Molina, Mª Isabel; Fernandez-San Jose, Patricia; Blanco-Kelly, Fiona; Riveiro-Alvarez, Rosa; Gilissen, Christian; Millan, Jose M; Avila-Fernandez, Almudena; Ayuso, Carmen

2016-01-01

Retinitis pigmentosa (RP) is a group of inherited progressive retinal dystrophies (RD) characterized by photoreceptor degeneration. RP is highly heterogeneous both clinically and genetically, which complicates the identification of causative genes and mutations. Targeted next-generation sequencing (NGS) has been demonstrated to be an effective strategy for the detection of mutations in RP. In our study, an in-house gene panel comprising 75 known RP genes was used to analyze a cohort of 47 unrelated Spanish families pre-classified as autosomal recessive or isolated RP. Disease-causing mutations were found in 27 out of 47 cases achieving a mutation detection rate of 57.4%. In total, 33 pathogenic mutations were identified, 20 of which were novel mutations (60.6%). Furthermore, not only single nucleotide variations but also copy-number variations, including three large deletions in the USH2A and EYS genes, were identified. Finally seven out of 27 families, displaying mutations in the ABCA4, RP1, RP2 and USH2A genes, could be genetically or clinically reclassified. These results demonstrate the potential of our panel-based NGS strategy in RP diagnosis. PMID:26806561

Tin-gallium-oxide-based UV-C detectors

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Partha; Toporkov, Mykyta; Schoenfeld, Winston V.

2018-02-01

The emergence of conductive gallium oxide single crystal substrates offers the potential for vertical Schottky detectors operating in the UV-C spectral region. We report here on our recent work in the development of Tin Gallium oxide (TGO) thin film metal-semiconductor-metal (MSM) and Schottky detectors using plasma-assisted molecular beam epitaxy on c plane sapphire and bulk Ga2O3 substrates. Tin alloying of gallium oxide thin films was found to systematically reduce the optical band gap of the compound, providing tunability in the UV-C spectral region. Tin concentration in the TGO epilayers was found to be highly dependent on growth conditions, and Ga flux in particular. First attempts to demonstrate vertical Schottky photodetectors using TGO epilayers on bulk n-type Ga2O3 substrates were successful. Resultant devices showed strong photoresponse to UV-C light with peak responsivities clearly red shifted in comparison to Ga2O3 homoepitaxial Schottky detectors due to TGO alloying.

Panel Flutter Emulation Using a Few Concentrated Forces

NASA Astrophysics Data System (ADS)

Dhital, Kailash; Han, Jae-Hung

2018-04-01

The objective of this paper is to study the feasibility of panel flutter emulation using a few concentrated forces. The concentrated forces are considered to be equivalent to aerodynamic forces. The equivalence is carried out using surface spline method and principle of virtual work. The structural modeling of the plate is based on the classical plate theory and the aerodynamic modeling is based on the piston theory. The present approach differs from the linear panel flutter analysis in scheming the modal aerodynamics forces with unchanged structural properties. The solutions for the flutter problem are obtained numerically using the standard eigenvalue procedure. A few concentrated forces were considered with an optimization effort to decide their optimal locations. The optimization process is based on minimizing the error between the flutter bounds from emulated and linear flutter analysis method. The emulated flutter results for the square plate of four different boundary conditions using six concentrated forces are obtained with minimal error to the reference value. The results demonstrated the workability and viability of using concentrated forces in emulating real panel flutter. In addition, the paper includes the parametric studies of linear panel flutter whose proper literatures are not available.

Comparing performances of a CdTe X-ray spectroscopic detector and an X-ray dual-energy sandwich detector

NASA Astrophysics Data System (ADS)

Gorecki, A.; Brambilla, A.; Moulin, V.; Gaborieau, E.; Radisson, P.; Verger, L.

2013-11-01

Multi-energy (ME) detectors are becoming a serious alternative to classical dual-energy sandwich (DE-S) detectors for X-ray applications such as medical imaging or explosive detection. They can use the full X-ray spectrum of irradiated materials, rather than disposing only of low and high energy measurements, which may be mixed. In this article, we intend to compare both simulated and real industrial detection systems, operating at a high count rate, independently of the dimensions of the measurements and independently of any signal processing methods. Simulations or prototypes of similar detectors have already been compared (see [1] for instance), but never independently of estimation methods and never with real detectors. We have simulated both an ME detector made of CdTe - based on the characteristics of the MultiX ME100 and - a DE-S detector - based on the characteristics of the Detection Technology's X-Card 1.5-64DE model. These detectors were compared to a perfect spectroscopic detector and an optimal DE-S detector. For comparison purposes, two approaches were investigated. The first approach addresses how to distinguise signals, while the second relates to identifying materials. Performance criteria were defined and comparisons were made over a range of material thicknesses and with different photon statistics. Experimental measurements in a specific configuration were acquired to checks simulations. Results showed good agreement between the ME simulation and the ME100 detector. Both criteria seem to be equivalent, and the ME detector performs 3.5 times better than the DE-S detector with same photon statistics based on simulations and experimental measurements. Regardless of the photon statistics ME detectors appeared more efficient than DE-S detectors for all material thicknesses between 1 and 9 cm when measuring plastics with an attenuation signature close that of explosive materials. This translates into an improved false detection rate (FDR): DE