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Sample records for 2d x-ray fluoroscopy

  1. Efficient feature-based 2D/3D registration of transesophageal echocardiography to x-ray fluoroscopy for cardiac interventions

    NASA Astrophysics Data System (ADS)

    Hatt, Charles R.; Speidel, Michael A.; Raval, Amish N.

    2014-03-01

    We present a novel 2D/ 3D registration algorithm for fusion between transesophageal echocardiography (TEE) and X-ray fluoroscopy (XRF). The TEE probe is modeled as a subset of 3D gradient and intensity point features, which facilitates efficient 3D-to-2D perspective projection. A novel cost-function, based on a combination of intensity and edge features, evaluates the registration cost value without the need for time-consuming generation of digitally reconstructed radiographs (DRRs). Validation experiments were performed with simulations and phantom data. For simulations, in silica XRF images of a TEE probe were generated in a number of different pose configurations using a previously acquired CT image. Random misregistrations were applied and our method was used to recover the TEE probe pose and compare the result to the ground truth. Phantom experiments were performed by attaching fiducial markers externally to a TEE probe, imaging the probe with an interventional cardiac angiographic x-ray system, and comparing the pose estimated from the external markers to that estimated from the TEE probe using our algorithm. Simulations found a 3D target registration error of 1.08(1.92) mm for biplane (monoplane) geometries, while the phantom experiment found a 2D target registration error of 0.69mm. For phantom experiments, we demonstrated a monoplane tracking frame-rate of 1.38 fps. The proposed feature-based registration method is computationally efficient, resulting in near real-time, accurate image based registration between TEE and XRF.

  2. Automatic localization of vertebral levels in x-ray fluoroscopy using 3D-2D registration: a tool to reduce wrong-site surgery.

    PubMed

    Otake, Y; Schafer, S; Stayman, J W; Zbijewski, W; Kleinszig, G; Graumann, R; Khanna, A J; Siewerdsen, J H

    2012-09-07

    Surgical targeting of the incorrect vertebral level (wrong-level surgery) is among the more common wrong-site surgical errors, attributed primarily to the lack of uniquely identifiable radiographic landmarks in the mid-thoracic spine. The conventional localization method involves manual counting of vertebral bodies under fluoroscopy, is prone to human error and carries additional time and dose. We propose an image registration and visualization system (referred to as LevelCheck), for decision support in spine surgery by automatically labeling vertebral levels in fluoroscopy using a GPU-accelerated, intensity-based 3D-2D (namely CT-to-fluoroscopy) registration. A gradient information (GI) similarity metric and a CMA-ES optimizer were chosen due to their robustness and inherent suitability for parallelization. Simulation studies involved ten patient CT datasets from which 50 000 simulated fluoroscopic images were generated from C-arm poses selected to approximate the C-arm operator and positioning variability. Physical experiments used an anthropomorphic chest phantom imaged under real fluoroscopy. The registration accuracy was evaluated as the mean projection distance (mPD) between the estimated and true center of vertebral levels. Trials were defined as successful if the estimated position was within the projection of the vertebral body (namely mPD <5 mm). Simulation studies showed a success rate of 99.998% (1 failure in 50 000 trials) and computation time of 4.7 s on a midrange GPU. Analysis of failure modes identified cases of false local optima in the search space arising from longitudinal periodicity in vertebral structures. Physical experiments demonstrated the robustness of the algorithm against quantum noise and x-ray scatter. The ability to automatically localize target anatomy in fluoroscopy in near-real-time could be valuable in reducing the occurrence of wrong-site surgery while helping to reduce radiation exposure. The method is applicable beyond the

  3. Automatic localization of vertebral levels in x-ray fluoroscopy using 3D-2D registration: a tool to reduce wrong-site surgery

    NASA Astrophysics Data System (ADS)

    Otake, Y.; Schafer, S.; Stayman, J. W.; Zbijewski, W.; Kleinszig, G.; Graumann, R.; Khanna, A. J.; Siewerdsen, J. H.

    2012-09-01

    Surgical targeting of the incorrect vertebral level (wrong-level surgery) is among the more common wrong-site surgical errors, attributed primarily to the lack of uniquely identifiable radiographic landmarks in the mid-thoracic spine. The conventional localization method involves manual counting of vertebral bodies under fluoroscopy, is prone to human error and carries additional time and dose. We propose an image registration and visualization system (referred to as LevelCheck), for decision support in spine surgery by automatically labeling vertebral levels in fluoroscopy using a GPU-accelerated, intensity-based 3D-2D (namely CT-to-fluoroscopy) registration. A gradient information (GI) similarity metric and a CMA-ES optimizer were chosen due to their robustness and inherent suitability for parallelization. Simulation studies involved ten patient CT datasets from which 50 000 simulated fluoroscopic images were generated from C-arm poses selected to approximate the C-arm operator and positioning variability. Physical experiments used an anthropomorphic chest phantom imaged under real fluoroscopy. The registration accuracy was evaluated as the mean projection distance (mPD) between the estimated and true center of vertebral levels. Trials were defined as successful if the estimated position was within the projection of the vertebral body (namely mPD <5 mm). Simulation studies showed a success rate of 99.998% (1 failure in 50 000 trials) and computation time of 4.7 s on a midrange GPU. Analysis of failure modes identified cases of false local optima in the search space arising from longitudinal periodicity in vertebral structures. Physical experiments demonstrated the robustness of the algorithm against quantum noise and x-ray scatter. The ability to automatically localize target anatomy in fluoroscopy in near-real-time could be valuable in reducing the occurrence of wrong-site surgery while helping to reduce radiation exposure. The method is applicable beyond

  4. Biplanar x-ray fluoroscopy for sacroiliac joint fusion.

    PubMed

    Vanaclocha-Vanaclocha, Vicente; Verdú-López, Francisco; Sáiz-Sapena, Nieves; Herrera, Juan Manuel; Rivera-Paz, Marlon

    2016-07-01

    Chronic pain originating from the sacroiliac joint (SI) can cause severe dysfunction. Although many patients respond to conservative management with NSAIDs, some do need further treatment in the form of SI joint fusion (SIJF). To achieve safe and successful SIJF, intraoperative x-ray fluoroscopy is mandatory to avoid serious damages to nearby vascular and neural structures. Each step of the procedure has to be confirmed by anteroposterior (AP) and lateral projections. With a single-arm x-ray, the arch has to be moved back and forth for the AP and lateral projections, and this lengthens the procedure. To achieve the same results in less time, the authors introduced simultaneous biplanar fluoroscopy with 2 x-ray arches. After the patient is positioned prone with the legs spread apart in the so-called Da Vinci position, one x-ray arch for the lateral projection is placed at a right angle to the patient, and a second x-ray machine is placed with its arch between the legs of the patient. This allows simultaneous AP and lateral x-ray projections and, in the authors' hands, markedly speeds up the procedure. Biplanar fluoroscopy allows excellent AP and lateral projections to be made quickly at any time during the surgical procedure. This is particularly useful in cases of bilateral SI joint fusion if both sides are done at the same time. The video can be found here: https://youtu.be/TX5gz8c765M .

  5. Depth-resolved registration of transesophageal echo to x-ray fluoroscopy using an inverse geometry fluoroscopy system

    PubMed Central

    Hatt, Charles R.; Tomkowiak, Michael T.; Dunkerley, David A. P.; Slagowski, Jordan M.; Funk, Tobias; Raval, Amish N.; Speidel, Michael A.

    2015-01-01

    Purpose: Image registration between standard x-ray fluoroscopy and transesophageal echocardiography (TEE) has recently been proposed. Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system designed for cardiac procedures. This study presents a method for 3D registration of SBDX and TEE images based on the tomosynthesis and 3D tracking capabilities of SBDX. Methods: The registration algorithm utilizes the stack of tomosynthetic planes produced by the SBDX system to estimate the physical 3D coordinates of salient key-points on the TEE probe. The key-points are used to arrive at an initial estimate of the probe pose, which is then refined using a 2D/3D registration method adapted for inverse geometry fluoroscopy. A phantom study was conducted to evaluate probe pose estimation accuracy relative to the ground truth, as defined by a set of coregistered fiducial markers. This experiment was conducted with varying probe poses and levels of signal difference-to-noise ratio (SDNR). Additional phantom and in vivo studies were performed to evaluate the correspondence of catheter tip positions in TEE and x-ray images following registration of the two modalities. Results: Target registration error (TRE) was used to characterize both pose estimation and registration accuracy. In the study of pose estimation accuracy, successful pose estimates (3D TRE < 5.0 mm) were obtained in 97% of cases when the SDNR was 5.9 or higher in seven out of eight poses. Under these conditions, 3D TRE was 2.32 ± 1.88 mm, and 2D (projection) TRE was 1.61 ± 1.36 mm. Probe localization error along the source-detector axis was 0.87 ± 1.31 mm. For the in vivo experiments, mean 3D TRE ranged from 2.6 to 4.6 mm and mean 2D TRE ranged from 1.1 to 1.6 mm. Anatomy extracted from the echo images appeared well aligned when projected onto the SBDX images. Conclusions: Full 6 DOF image registration between SBDX and TEE is feasible and accurate to within 5 mm. Future studies will focus on

  6. Depth-resolved registration of transesophageal echo to x-ray fluoroscopy using an inverse geometry fluoroscopy system

    SciTech Connect

    Hatt, Charles R.; Tomkowiak, Michael T.; Dunkerley, David A. P.; Slagowski, Jordan M.; Funk, Tobias; Raval, Amish N.; Speidel, Michael A.

    2015-12-15

    Purpose: Image registration between standard x-ray fluoroscopy and transesophageal echocardiography (TEE) has recently been proposed. Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system designed for cardiac procedures. This study presents a method for 3D registration of SBDX and TEE images based on the tomosynthesis and 3D tracking capabilities of SBDX. Methods: The registration algorithm utilizes the stack of tomosynthetic planes produced by the SBDX system to estimate the physical 3D coordinates of salient key-points on the TEE probe. The key-points are used to arrive at an initial estimate of the probe pose, which is then refined using a 2D/3D registration method adapted for inverse geometry fluoroscopy. A phantom study was conducted to evaluate probe pose estimation accuracy relative to the ground truth, as defined by a set of coregistered fiducial markers. This experiment was conducted with varying probe poses and levels of signal difference-to-noise ratio (SDNR). Additional phantom and in vivo studies were performed to evaluate the correspondence of catheter tip positions in TEE and x-ray images following registration of the two modalities. Results: Target registration error (TRE) was used to characterize both pose estimation and registration accuracy. In the study of pose estimation accuracy, successful pose estimates (3D TRE < 5.0 mm) were obtained in 97% of cases when the SDNR was 5.9 or higher in seven out of eight poses. Under these conditions, 3D TRE was 2.32 ± 1.88 mm, and 2D (projection) TRE was 1.61 ± 1.36 mm. Probe localization error along the source-detector axis was 0.87 ± 1.31 mm. For the in vivo experiments, mean 3D TRE ranged from 2.6 to 4.6 mm and mean 2D TRE ranged from 1.1 to 1.6 mm. Anatomy extracted from the echo images appeared well aligned when projected onto the SBDX images. Conclusions: Full 6 DOF image registration between SBDX and TEE is feasible and accurate to within 5 mm. Future studies will focus on

  7. 3D Reconstruction from X-ray Fluoroscopy for Clinical Veterinary Medicine using Differential Volume Rendering

    NASA Astrophysics Data System (ADS)

    Khongsomboon, Khamphong; Hamamoto, Kazuhiko; Kondo, Shozo

    3D reconstruction from ordinary X-ray equipment which is not CT or MRI is required in clinical veterinary medicine. Authors have already proposed a 3D reconstruction technique from X-ray photograph to present bone structure. Although the reconstruction is useful for veterinary medicine, the thechnique has two problems. One is about exposure of X-ray and the other is about data acquisition process. An x-ray equipment which is not special one but can solve the problems is X-ray fluoroscopy. Therefore, in this paper, we propose a method for 3D-reconstruction from X-ray fluoroscopy for clinical veterinary medicine. Fluoroscopy is usually used to observe a movement of organ or to identify a position of organ for surgery by weak X-ray intensity. Since fluoroscopy can output a observed result as movie, the previous two problems which are caused by use of X-ray photograph can be solved. However, a new problem arises due to weak X-ray intensity. Although fluoroscopy can present information of not only bone structure but soft tissues, the contrast is very low and it is very difficult to recognize some soft tissues. It is very useful to be able to observe not only bone structure but soft tissues clearly by ordinary X-ray equipment in the field of clinical veterinary medicine. To solve this problem, this paper proposes a new method to determine opacity in volume rendering process. The opacity is determined according to 3D differential coefficient of 3D reconstruction. This differential volume rendering can present a 3D structure image of multiple organs volumetrically and clearly for clinical veterinary medicine. This paper shows results of simulation and experimental investigation of small dog and evaluation by veterinarians.

  8. SU-C-18C-03: Dual-Energy X-Ray Fluoroscopy Imaging System

    SciTech Connect

    Virshup, G; Richmond, M; Mostafavi, H; Ganguly, A; Fu, D

    2014-06-01

    Purpose: This work studies the clinical utility of dual energy (DE) subtraction fluoroscopy for fiducial-free tumor tracking in lung radiation therapy (RT). Improvement in tumor visualization and quantification of tumor shift within a breathing cycle were analyzed. Methods: Twenty subjects who were undergoing RT for lung cancer were recruited following institutional review board approval. The subjects had a range of tumor sizes, locations in the lungs, and body sizes. An x-ray imaging system was setup with the following components: (a) x-ray tube (Varian G-242, Varian Medical Systems (VMS), CA) (b) flat panel detector (4030CB, VMS, CA) and (c) x-ray generator (EPS 50RF, EMD, Canada). Firmware and software modifications were made to the generator to allow 10 x-ray pulse pairs with alternating low/high kV, 100 ms apart for ∼4s (one breathing cycle). Images were obtained at 4 angles: 0°, 45°, 90° and 135°. Weighted subtraction of a kV-pair image set was used to create a “bone-free” image of the lungs. The 2D tumor-shift in each subtracted image and the 3D shift during a breathing cycle was calculated using all views. Results: The subjects enrolled had the following statistics: average age 62.3±7.1 years, 5 female/15 male, 11 had tumors on the right and 9 on the left and the average tumor size was ∼31.4±10.8 mm. X-ray imaging conditions for the pulse pairs were: 70/120 kVp, 280/221 mA and 65/8 ms. For views where these parameters were insufficient 80/130 kVp, 280/221 mA and 60/12 ms was used. Tumor visibility improved for 0°, 45°, 90° and 135° in 100%, 55%, 75% and 80% of the cases respectively. Tumor shift during a breathing cycle was: 2.4±1.0 mm AP, 2.7±1.4 mm LR and 7.6±4.8 mm IS. Conclusion: DE subtraction fluoroscopy allowed improved visualization and quantification of movement of tumors in the lungs during a breathing cycle. This study was entirely funded by Varian Medical Systems.

  9. Fluoroscopy

    MedlinePlus

    ... the Medical X-ray Imaging webpage about radiation management, quality assurance (including diagnostic reference levels), and training, the following resources provide information specific to radiation management, facility quality assurance, and training in fluoroscopy: International Commission on ...

  10. Monte Carlo simulation of inverse geometry x-ray fluoroscopy using a modified MC-GPU framework

    NASA Astrophysics Data System (ADS)

    Dunkerley, David A. P.; Tomkowiak, Michael T.; Slagowski, Jordan M.; McCabe, Bradley P.; Funk, Tobias; Speidel, Michael A.

    2015-03-01

    Scanning-Beam Digital X-ray (SBDX) is a technology for low-dose fluoroscopy that employs inverse geometry x-ray beam scanning. To assist with rapid modeling of inverse geometry x-ray systems, we have developed a Monte Carlo (MC) simulation tool based on the MC-GPU framework. MC-GPU version 1.3 was modified to implement a 2D array of focal spot positions on a plane, with individually adjustable x-ray outputs, each producing a narrow x-ray beam directed toward a stationary photon-counting detector array. Geometric accuracy and blurring behavior in tomosynthesis reconstructions were evaluated from simulated images of a 3D arrangement of spheres. The artifact spread function from simulation agreed with experiment to within 1.6% (rRMSD). Detected x-ray scatter fraction was simulated for two SBDX detector geometries and compared to experiments. For the current SBDX prototype (10.6 cm wide by 5.3 cm tall detector), x-ray scatter fraction measured 2.8-6.4% (18.6-31.5 cm acrylic, 100 kV), versus 2.2-5.0% in MC simulation. Experimental trends in scatter versus detector size and phantom thickness were observed in simulation. For dose evaluation, an anthropomorphic phantom was imaged using regular and regional adaptive exposure (RAE) scanning. The reduction in kerma-area-product resulting from RAE scanning was 45% in radiochromic film measurements, versus 46% in simulation. The integral kerma calculated from TLD measurement points within the phantom was 57% lower when using RAE, versus 61% lower in simulation. This MC tool may be used to estimate tomographic blur, detected scatter, and dose distributions when developing inverse geometry x-ray systems.

  11. Monte Carlo simulation of inverse geometry x-ray fluoroscopy using a modified MC-GPU framework.

    PubMed

    Dunkerley, David A P; Tomkowiak, Michael T; Slagowski, Jordan M; McCabe, Bradley P; Funk, Tobias; Speidel, Michael A

    2015-02-21

    Scanning-Beam Digital X-ray (SBDX) is a technology for low-dose fluoroscopy that employs inverse geometry x-ray beam scanning. To assist with rapid modeling of inverse geometry x-ray systems, we have developed a Monte Carlo (MC) simulation tool based on the MC-GPU framework. MC-GPU version 1.3 was modified to implement a 2D array of focal spot positions on a plane, with individually adjustable x-ray outputs, each producing a narrow x-ray beam directed toward a stationary photon-counting detector array. Geometric accuracy and blurring behavior in tomosynthesis reconstructions were evaluated from simulated images of a 3D arrangement of spheres. The artifact spread function from simulation agreed with experiment to within 1.6% (rRMSD). Detected x-ray scatter fraction was simulated for two SBDX detector geometries and compared to experiments. For the current SBDX prototype (10.6 cm wide by 5.3 cm tall detector), x-ray scatter fraction measured 2.8-6.4% (18.6-31.5 cm acrylic, 100 kV), versus 2.1-4.5% in MC simulation. Experimental trends in scatter versus detector size and phantom thickness were observed in simulation. For dose evaluation, an anthropomorphic phantom was imaged using regular and regional adaptive exposure (RAE) scanning. The reduction in kerma-area-product resulting from RAE scanning was 45% in radiochromic film measurements, versus 46% in simulation. The integral kerma calculated from TLD measurement points within the phantom was 57% lower when using RAE, versus 61% lower in simulation. This MC tool may be used to estimate tomographic blur, detected scatter, and dose distributions when developing inverse geometry x-ray systems.

  12. Estimation of three-dimensional knee joint movement using bi-plane x-ray fluoroscopy and 3D-CT

    NASA Astrophysics Data System (ADS)

    Haneishi, Hideaki; Fujita, Satoshi; Kohno, Takahiro; Suzuki, Masahiko; Miyagi, Jin; Moriya, Hideshige

    2005-04-01

    Acquisition of exact information of three-dimensional knee joint movement is desired in plastic surgery. Conventional X-ray fluoroscopy provides dynamic but just two-dimensional projected image. On the other hand, three-dimensional CT provides three-dimensional but just static image. In this paper, a method for acquiring three-dimensional knee joint movement using both bi-plane, dynamic X-ray fluoroscopy and static three-dimensional CT is proposed. Basic idea is use of 2D/3D registration using digitally reconstructed radiograph (DRR) or virtual projection of CT data. Original ideal is not new but the application of bi-plane fluoroscopy to natural bones of knee is reported for the first time. The technique was applied to two volunteers and successful results were obtained. Accuracy evaluation through computer simulation and phantom experiment with a knee joint of a pig were also conducted.

  13. Multimodality image guidance system integrating X-ray fluoroscopy and ultrasound image streams with electromagnetic tracking

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Luis F.; Shechter, Guy; Stanton, Douglas; Dalal, Sandeep; Elgort, Daniel; Manzke, Robert; Chan, Raymond C.; Zagorchev, Lyubomir

    2007-03-01

    This work presents an integrated system for multimodality image guidance of minimally invasive medical procedures. This software and hardware system offers real-time integration and registration of multiple image streams with localization data from navigation systems. All system components communicate over a local area Ethernet network, enabling rapid and flexible deployment configurations. As a representative configuration, we use X-ray fluoroscopy (XF) and ultrasound (US) imaging. The XF imaging system serves as the world coordinate system, with gantry geometry derived from the imaging system, and patient table position tracked with a custom-built measurement device using linear encoders. An electromagnetic (EM) tracking system is registered to the XF space using a custom imaging phantom that is also tracked by the EM system. The RMS fiducial registration error for the EM to X-ray registration was 2.19 mm, and the RMS target registration error measured with an EM-tracked catheter was 8.81 mm. The US image stream is subsequently registered to the XF coordinate system using EM tracking of the probe, following a calibration of the US image within the EM coordinate system. We present qualitative results of the system in operation, demonstrating the integration of live ultrasound imaging spatially registered to X-ray fluoroscopy with catheter localization using electromagnetic tracking.

  14. TU-F-BRF-04: Registration of 3D Transesophageal Echocardiography and X-Ray Fluoroscopy Using An Inverse Geometry X-Ray System

    SciTech Connect

    Speidel, M; Hatt, C; Tomkowiak, M; Raval, A; Funk, T

    2014-06-15

    Purpose: To develop a method for the fusion of 3D echocardiography and Scanning-Beam Digital X-ray (SBDX) fluoroscopy to assist with catheter device and soft tissue visualization during interventional procedures. Methods: SBDX is a technology for low-dose inverse geometry x-ray fluoroscopy that performs digital tomosynthesis at multiple planes in real time. In this study, transesophageal echocardiography (TEE) images were fused with SBDX images by estimating the 3D position and orientation (the “pose”) of the TEE probe within the x-ray coordinate system and then spatially transforming the TEE image data to match this pose. An initial pose estimate was obtained through tomosynthesis-based 3D localization of points along the probe perimeter. Position and angle estimates were then iteratively refined by comparing simulated projections of a 3D probe model against SBDX x-ray images. Algorithm performance was quantified by imaging a TEE probe in different known orientations and locations within the x-ray field (0-30 degree tilt angle, up to 50 mm translation). Fused 3D TEE/SBDX imaging was demonstrated by imaging a tissue-mimicking polyvinyl alcohol cylindrical cavity as a catheter was navigated along the cavity axis. Results: Detected changes in probe tilt angle agreed with the known changes to within 1.2 degrees. For a 50 mm translation along the source-detector axis, the detected translation was 50.3 mm. Errors for in-plane translations ranged from 0.1 to 0.9 mm. In a fused 3D TEE/SBDX display, the catheter device was well visualized and coincident with the device shadow in the TEE images. The TEE images portrayed phantom boundaries that were not evident under x-ray. Conclusion: Registration of soft tissue anatomy derived from TEE imaging and device imaging from SBDX x-ray fluoroscopy is feasible. The simultaneous 3D visualization of these two modalities may be useful in interventional procedures involving the navigation of devices to soft tissue anatomy.

  15. Real-time x-ray fluoroscopy-based catheter detection and tracking for cardiac electrophysiology interventions

    SciTech Connect

    Ma Yingliang; Housden, R. James; Razavi, Reza; Rhode, Kawal S.; Gogin, Nicolas; Cathier, Pascal; Gijsbers, Geert; Cooklin, Michael; O'Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo

    2013-07-15

    Purpose: X-ray fluoroscopically guided cardiac electrophysiology (EP) procedures are commonly carried out to treat patients with arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of a three-dimensional (3D) roadmap derived from preprocedural volumetric images can be used to add anatomical information. It is useful to know the position of the catheter electrodes relative to the cardiac anatomy, for example, to record ablation therapy locations during atrial fibrillation therapy. Also, the electrode positions of the coronary sinus (CS) catheter or lasso catheter can be used for road map motion correction.Methods: In this paper, the authors present a novel unified computational framework for image-based catheter detection and tracking without any user interaction. The proposed framework includes fast blob detection, shape-constrained searching and model-based detection. In addition, catheter tracking methods were designed based on the customized catheter models input from the detection method. Three real-time detection and tracking methods are derived from the computational framework to detect or track the three most common types of catheters in EP procedures: the ablation catheter, the CS catheter, and the lasso catheter. Since the proposed methods use the same blob detection method to extract key information from x-ray images, the ablation, CS, and lasso catheters can be detected and tracked simultaneously in real-time.Results: The catheter detection methods were tested on 105 different clinical fluoroscopy sequences taken from 31 clinical procedures. Two-dimensional (2D) detection errors of 0.50 {+-} 0.29, 0.92 {+-} 0.61, and 0.63 {+-} 0.45 mm as well as success rates of 99.4%, 97.2%, and 88.9% were achieved for the CS catheter, ablation catheter, and lasso catheter, respectively. With the tracking method, accuracies were increased to 0.45 {+-} 0.28, 0.64 {+-} 0.37, and 0.53 {+-} 0.38 mm and success rates increased to 100%, 99

  16. Three-dimensional tracking of cardiac catheters using an inverse geometry x-ray fluoroscopy system

    SciTech Connect

    Speidel, Michael A.; Tomkowiak, Michael T.; Raval, Amish N.; Van Lysel, Michael S.

    2010-12-15

    . The tracking precision of ablation and diagnostic catheter tips ranged from {+-}0.2 mm at the highest image fluence to {+-}0.9 mm at the lowest fluence. Tracking precision depended on image fluence, the size of the tracked catheter electrode, and the contrast of the electrode. Conclusions: High speed multiplanar tomosynthesis with an inverse geometry x-ray fluoroscopy system enables 3D tracking of multiple high-contrast objects at the rate of fluoroscopic imaging. The SBDX system is capable of tracking electrodes in standard cardiac catheters with approximately 1 mm accuracy and precision.

  17. Unsupervised Learning for Robust Respiratory Signal Estimation from X-Ray Fluoroscopy.

    PubMed

    Fischer, Peter; Pohl, Thomas; Faranesh, Anthony; Maier, Andreas; Hornegger, Joachim

    2016-09-16

    Respiratory signals are required for image gating and motion compensation in minimally invasive interventions. In X-ray fluoroscopy, extraction of a respiratory signal can be challenging due to characteristics of interventional imaging, in particular injection of contrast agent and automatic exposure control. We present a novel method for respiratory signal extraction based on dimensionality reduction that can tolerate these events. Images are divided into patches of multiple sizes. Low-dimensional embeddings are generated for each patch using illumination-invariant kernel PCA. Patches with respiratory information are selected automatically by agglomerative clustering. The signals from this respiratory cluster are combined robustly to a single respiratory signal. In the experiments, we evaluate our method on a variety of scenarios. If the diaphragm is visible, we track its superiorinferior motion as ground truth. Our method has a correlation coefficient of more than 91% with the ground truth irrespective of whether or not contrast agent injection or automatic exposure control occur. Additionally, we show that very similar signals are estimated from biplane sequences and from sequences without visible diaphragm. Since all these cases are handled automatically, the method is robust enough to be considered for use in a clinical setting.

  18. Effect of segmentation errors on 3D-to-2D registration of implant models in X-ray images.

    PubMed

    Mahfouz, Mohamed R; Hoff, William A; Komistek, Richard D; Dennis, Douglas A

    2005-02-01

    In many biomedical applications, it is desirable to estimate the three-dimensional (3D) position and orientation (pose) of a metallic rigid object (such as a knee or hip implant) from its projection in a two-dimensional (2D) X-ray image. If the geometry of the object is known, as well as the details of the image formation process, then the pose of the object with respect to the sensor can be determined. A common method for 3D-to-2D registration is to first segment the silhouette contour from the X-ray image; that is, identify all points in the image that belong to the 2D silhouette and not to the background. This segmentation step is then followed by a search for the 3D pose that will best match the observed contour with a predicted contour. Although the silhouette of a metallic object is often clearly visible in an X-ray image, adjacent tissue and occlusions can make the exact location of the silhouette contour difficult to determine in places. Occlusion can occur when another object (such as another implant component) partially blocks the view of the object of interest. In this paper, we argue that common methods for segmentation can produce errors in the location of the 2D contour, and hence errors in the resulting 3D estimate of the pose. We show, on a typical fluoroscopy image of a knee implant component, that interactive and automatic methods for segmentation result in segmented contours that vary significantly. We show how the variability in the 2D contours (quantified by two different metrics) corresponds to variability in the 3D poses. Finally, we illustrate how traditional segmentation methods can fail completely in the (not uncommon) cases of images with occlusion.

  19. [Improvement of method of determining fluoroscopy loading factor in digital angiographic x-ray system with a flat panel detector].

    PubMed

    Sato, Hisaya; Kato, Kyoichi; Maruyama, Masahiro; Okada, Keigo; Miura, Yoshiaki; Nakanishi, Isao; Nitta, Masaru; Nakazawa, Yasuo

    2010-07-20

    A catheterization study and treatment of coronary arteriopathy are performed by investigating the coronary artery from different angles to find the region to be treated. In doing so, our system always started from the initial value of the loading factor, using this only for the first time, and the system started from the last loading factor the second time and later, at all angles. Therefore, depending on the angle, the loading factor at the start of fluoroscopy sometimes became unstable, and it took time to stabilize. This made the starting image too dark (undershoot x-ray condition) or fogged by halation (overshoot x-ray condition). With the system manufacturer, we developed a tube voltage and tube current setting method for the initial value of the loading factor. We installed software which preset the loading factor at the start of fluoroscopy depending on the angle, and an auto memory function of the last loading factor for each angle. This function allows the system to control the tube voltage and tube current for any angle. As a result, the system can acquire a more stabilized image from the start of fluoroscopy. This method of determining the initial loading factor is an effective way to stabilize the fluoroscopy image quickly.

  20. SU-E-T-140: Dynamic Wave Arc Trajectory Verification Using KV X-Ray Fluoroscopy

    SciTech Connect

    Burghelea, M; Poels, K; Depuydt, T; Tournel, K; Verellen, D; De Ridder, M

    2014-06-01

    Purpose: Purpose: This study investigates the geometric accuracy of simultaneous Gantry/Ring rotation during Dynamic Wave Arc (DWA) delivery. Methods: The Vero SBRT system consists of a 6MV LINAC mounted on an O-ring gantry that can rotate around the vertical axis (±60°), similar to couch rotation on C-arm gantries. To provide CBCT and fluoroscopy imaging functionalities, two orthogonal kV imaging units are attached to the O-ring at −45°/+45° from the beam axis.Dynamic Wave Arc maximizes Vero's motion capabilities by employing synchronized gantry and ring motion on a complex non-coplanar trajectory in combination with aperture based optimized MLC segments.Four wave arc trajectories (T1-4) were delivered using a cubic phantom with a configuration of five lead beads. O-ring gantry position information was retrieved through continuous dual-source kV X-ray image acquisition during DWA. An in-house algorithm read in the image set, extracted the projected marker positions and determined the angulation through reconstruction of the beam source position. The geometric error was quantified as the distance between the independently detected positions from kV-images and reference trajectory derived from the treatment plan in the Ring-Gantry space. Results: The average displacement between the 3D gantry/ring positions reconstructed from the fluoroscopy images and the reference trajectory was 0.346 mm (SD 0,171) for T1. A mean offset of 0.348 mm (SD 0,182) and 0.357 mm (SD 0.194) was observed for trajectory T2(2segmens) and T3(4segments), respectively. The saw shape T4 presented a mean geometric error of 0.363 (SD 0.156). The overall systematic error of 0.350 was caused by the difference between planned reference trajectory created by linear interpolation between CP, and the machine delivery following a spline curve. Conclusion: An independent geometric QA approach has been developed for DWA delivery verification, successfully applied on diverse trajectories and disclosed

  1. X-Ray Detector for Digital Fluoroscopy and Digital Radiography in Medical Imaging

    NASA Astrophysics Data System (ADS)

    Saito, Keiichi

    Recently digital X-ray detectors are developed for medical imaging. By comparison with the structure of X-ray image intensifier system and X-ray flat panel detector (FPD), the dynamic of digital images is more superior and would result in enhanced diagnosis. Moreover the difference from the detective quantum efficiency (DQE) of X-ray image intensifier and FPD is shown as the significant index of X-ray image quality.

  2. Remapping of digital subtraction angiography on a standard fluoroscopy system using 2D-3D registration

    NASA Astrophysics Data System (ADS)

    Alhrishy, Mazen G.; Varnavas, Andreas; Guyot, Alexis; Carrell, Tom; King, Andrew; Penney, Graeme

    2015-03-01

    Fluoroscopy-guided endovascular interventions are being performing for more and more complex cases with longer screening times. However, X-ray is much better at visualizing interventional devices and dense structures compared to vasculature. To visualise vasculature, angiography screening is essential but requires the use of iodinated contrast medium (ICM) which is nephrotoxic. Acute kidney injury is the main life-threatening complication of ICM. Digital subtraction angiography (DSA) is also often a major contributor to overall patient radiation dose (81% reported). Furthermore, a DSA image is only valid for the current interventional view and not the new view once the C-arm is moved. In this paper, we propose the use of 2D-3D image registration between intraoperative images and the preoperative CT volume to facilitate DSA remapping using a standard fluoroscopy system. This allows repeated ICM-free DSA and has the potential to enable a reduction in ICM usage and radiation dose. Experiments were carried out using 9 clinical datasets. In total, 41 DSA images were remapped. For each dataset, the maximum and averaged remapping accuracy error were calculated and presented. Numerical results showed an overall averaged error of 2.50 mm, with 7 patients scoring averaged errors < 3 mm and 2 patients < 6 mm.

  3. 2D/3D registration for X-ray guided bronchoscopy using distance map classification.

    PubMed

    Xu, Di; Xu, Sheng; Herzka, Daniel A; Yung, Rex C; Bergtholdt, Martin; Gutierrez, Luis F; McVeigh, Elliot R

    2010-01-01

    In X-ray guided bronchoscopy of peripheral pulmonary lesions, airways and nodules are hardly visible in X-ray images. Transbronchial biopsy of peripheral lesions is often carried out blindly, resulting in degraded diagnostic yield. One solution of this problem is to superimpose the lesions and airways segmented from preoperative 3D CT images onto 2D X-ray images. A feature-based 2D/3D registration method is proposed for the image fusion between the datasets of the two imaging modalities. Two stereo X-ray images are used in the algorithm to improve the accuracy and robustness of the registration. The algorithm extracts the edge features of the bony structures from both CT and X-ray images. The edge points from the X-ray images are categorized into eight groups based on the orientation information of their image gradients. An orientation dependent Euclidean distance map is generated for each group of X-ray feature points. The distance map is then applied to the edge points of the projected CT images whose gradient orientations are compatible with the distance map. The CT and X-ray images are registered by matching the boundaries of the projected CT segmentations to the closest edges of the X-ray images after the orientation constraint is satisfied. Phantom and clinical studies were carried out to validate the algorithm's performance, showing a registration accuracy of 4.19(± 0.5) mm with 48.39(± 9.6) seconds registration time. The algorithm was also evaluated on clinical data, showing promising registration accuracy and robustness.

  4. Fast catheter segmentation from echocardiographic sequences based on segmentation from corresponding X-ray fluoroscopy for cardiac catheterization interventions.

    PubMed

    Wu, Xianliang; Housden, James; Ma, YingLiang; Razavi, Benjamin; Rhode, Kawal; Rueckert, Daniel

    2015-04-01

    Echocardiography is a potential alternative to X-ray fluoroscopy in cardiac catheterization given its richness in soft tissue information and its lack of ionizing radiation. However, its small field of view and acoustic artifacts make direct automatic segmentation of the catheters very challenging. In this study, a fast catheter segmentation framework for echocardiographic imaging guided by the segmentation of corresponding X-ray fluoroscopic imaging is proposed. The complete framework consists of: 1) catheter initialization in the first X-ray frame; 2) catheter tracking in the rest of the X-ray sequence; 3) fast registration of corresponding X-ray and ultrasound frames; and 4) catheter segmentation in ultrasound images guided by the results of both X-ray tracking and fast registration. The main contributions include: 1) a Kalman filter-based growing strategy with more clinical data evalution; 2) a SURF detector applied in a constrained search space for catheter segmentation in ultrasound images; 3) a two layer hierarchical graph model to integrate and smooth catheter fragments into a complete catheter; and 4) the integration of these components into a system for clinical applications. This framework is evaluated on five sequences of porcine data and four sequences of patient data comprising more than 3000 X-ray frames and more than 1000 ultrasound frames. The results show that our algorithm is able to track the catheter in ultrasound images at 1.3 s per frame, with an error of less than 2 mm. However, although this may satisfy the accuracy for visualization purposes and is also fast, the algorithm still needs to be further accelerated for real-time clinical applications.

  5. 2D X-ray scanner and its uses in laboratory reservoir characterization measurements

    SciTech Connect

    Maloney, D.; Doggett, K.

    1997-08-01

    X-ray techniques are used in petroleum laboratories for a variety of reservoir characterization measurements. This paper describes the configuration of a 2D X-ray scanner and many of the ways in which it simplifies and improves accuracy`s of laboratory measurements. Linear X-ray scanners are most often used to provide descriptions of fluid saturations within core plugs during flow tests. We configured our linear scanner for both horizontal and vertical movement. Samples can be scanned horizontally, vertically, or according to horizontal and vertical grids. X-ray measurements are fast, allowing measurements of two- and three-phase fluid saturations during both steady- and unsteady-state flow processes. Rock samples can be scanned while they are subjected to stress, pore pressure, and temperature conditions simulating those of a petroleum reservoir. Many types of measurements are possible by selecting appropriate X-ray power settings, dopes, filters, and collimator configurations. The scanner has been used for a variety of applications besides fluid saturation measurements. It is useful for measuring porosity distributions in rocks, concentrations of X-ray dopes within flow streams during tracer tests, gap widths in fracture flow cells, fluid interface levels in PVT cells and fluid separators, and other features and phenomena.

  6. 3D/2D image registration: the impact of X-ray views and their number.

    PubMed

    Tomazevic, Dejan; Likar, Bostjan; Pernus, Franjo

    2007-01-01

    An important part of image-guided radiation therapy or surgery is registration of a three-dimensional (3D) preoperative image to two-dimensional (2D) images of the patient. It is expected that the accuracy and robustness of a 3D/2D image registration method do not depend solely on the registration method itself but also on the number and projections (views) of intraoperative images. In this study, we systematically investigate these factors by using registered image data, comprising of CT and X-ray images of a cadaveric lumbar spine phantom and the recently proposed 3D/2D registration method. The results indicate that the proportion of successful registrations (robustness) significantly increases when more X-ray images are used for registration.

  7. Respiratory motion compensated overlay of surface models from cardiac MR on interventional x-ray fluoroscopy for guidance of cardiac resynchronization therapy procedures

    NASA Astrophysics Data System (ADS)

    Manzke, R.; Bornstedt, A.; Lutz, A.; Schenderlein, M.; Hombach, V.; Binner, L.; Rasche, V.

    2010-02-01

    Various multi-center trials have shown that cardiac resynchronization therapy (CRT) is an effective procedure for patients with end-stage drug invariable heart failure (HF). Despite the encouraging results of CRT, at least 30% of patients do not respond to the treatment. Detailed knowledge of the cardiac anatomy (coronary venous tree, left ventricle), functional parameters (i.e. ventricular synchronicity) is supposed to improve CRT patient selection and interventional lead placement for reduction of the number of non-responders. As a pre-interventional imaging modality, cardiac magnetic resonance (CMR) imaging has the potential to provide all relevant information. With functional information from CMR optimal implantation target sites may be better identified. Pre-operative CMR could also help to determine whether useful vein target segments are available for lead placement. Fused with X-ray, the mainstay interventional modality, improved interventional guidance for lead-placement could further help to increase procedure outcome. In this contribution, we present novel and practicable methods for a) pre-operative functional and anatomical imaging of relevant cardiac structures to CRT using CMR, b) 2D-3D registration of CMR anatomy and functional meshes with X-ray vein angiograms and c) real-time capable breathing motion compensation for improved fluoroscopy mesh overlay during the intervention based on right ventricular pacer lead tracking. With these methods, enhanced interventional guidance for left ventricular lead placement is provided.

  8. X-ray beam modulation, image acquisition and real-time processing in region-of-interest fluoroscopy

    NASA Astrophysics Data System (ADS)

    Yang, Chang-Ying Joseph

    2000-07-01

    Region of interest (ROI) fluoroscopy is a technique whereby a partially attenuating filter with an aperture in the center is placed in the x-ray beam between the source and the patient The part of the x-ray beam going through the filter aperture un-attenuated is used to project the main features of interest in the patient to form the ROI in each fluoroscopic image. The periphery of the image is formed by the projection of the features needed only for reference using the part of the attenuated x-ray beam passing through the filter. This technique can substantially reduce patient and staff dose and improve the image quality in the ROI of the image. By using Gd for the filter material, it is even possible to improve the x-ray attenuation contrast in the periphery. However, real-time image processing is needed to compensate for the x-ray intensity attenuation in the periphery so that the brightness in the two parts of the fluoroscopic image is linearity is restored. Based on the method of binary masks, a system was developed to perform the real-time image processing with the flexibility to accommodate both the horizontal and vertical movement of the imaging chain relative to the patient. A binary mask is a binary image used to define those regions in the fluoroscopic image which should be processed and those which should not. A method of binary mask generation was proposed so the region defined as not to be processed in the binary mask maintains as close a resemblance as possible to the ROI of the fluoroscopic image. The construction method for the look-up table used for the processing of the periphery and its dependence on physical quantities were described and studied. An algorithm for constantly tracking the change of the ROI in the fluoroscopic images and selecting the proper corresponding binary mask was developed. The quality of the processed ROI fluoroscopic images such as brightness, contrast and noise were evaluated and compared using test phantoms. The test

  9. Snapshot 2D tomography via coded aperture x-ray scatter imaging

    PubMed Central

    MacCabe, Kenneth P.; Holmgren, Andrew D.; Tornai, Martin P.; Brady, David J.

    2015-01-01

    This paper describes a fan beam coded aperture x-ray scatter imaging system which acquires a tomographic image from each snapshot. This technique exploits cylindrical symmetry of the scattering cross section to avoid the scanning motion typically required by projection tomography. We use a coded aperture with a harmonic dependence to determine range, and a shift code to determine cross-range. Here we use a forward-scatter configuration to image 2D objects and use serial exposures to acquire tomographic video of motion within a plane. Our reconstruction algorithm also estimates the angular dependence of the scattered radiance, a step toward materials imaging and identification. PMID:23842254

  10. A real-time regional adaptive exposure method for saving dose-area product in x-ray fluoroscopy

    SciTech Connect

    Burion, Steve; Funk, Tobias; Speidel, Michael A.

    2013-05-15

    Purpose: Reduction of radiation dose in x-ray imaging has been recognized as a high priority in the medical community. Here the authors show that a regional adaptive exposure method can reduce dose-area product (DAP) in x-ray fluoroscopy. The authors' method is particularly geared toward providing dose savings for the pediatric population. Methods: The scanning beam digital x-ray system uses a large-area x-ray source with 8000 focal spots in combination with a small photon-counting detector. An imaging frame is obtained by acquiring and reconstructing up to 8000 detector images, each viewing only a small portion of the patient. Regional adaptive exposure was implemented by varying the exposure of the detector images depending on the local opacity of the object. A family of phantoms ranging in size from infant to obese adult was imaged in anteroposterior view with and without adaptive exposure. The DAP delivered to each phantom was measured in each case, and noise performance was compared by generating noise arrays to represent regional noise in the images. These noise arrays were generated by dividing the image into regions of about 6 mm{sup 2}, calculating the relative noise in each region, and placing the relative noise value of each region in a one-dimensional array (noise array) sorted from highest to lowest. Dose-area product savings were calculated as the difference between the ratio of DAP with adaptive exposure to DAP without adaptive exposure. The authors modified this value by a correction factor that matches the noise arrays where relative noise is the highest to report a final dose-area product savings. Results: The average dose-area product saving across the phantom family was (42 {+-} 8)% with the highest dose-area product saving in the child-sized phantom (50%) and the lowest in the phantom mimicking an obese adult (23%). Conclusions: Phantom measurements indicate that a regional adaptive exposure method can produce large DAP savings without

  11. Stent enhancement in digital x-ray fluoroscopy using an adaptive feature enhancement filter

    NASA Astrophysics Data System (ADS)

    Jiang, Yuhao; Zachary, Josey

    2016-03-01

    Fluoroscopic images belong to the classes of low contrast and high noise. Simply lowering radiation dose will render the images unreadable. Feature enhancement filters can reduce patient dose by acquiring images at low dose settings and then digitally restoring them to the original quality. In this study, a stent contrast enhancement filter is developed to selectively improve the contrast of stent contour without dramatically boosting the image noise including quantum noise and clinical background noise. Gabor directional filter banks are implemented to detect the edges and orientations of the stent. A high orientation resolution of 9° is used. To optimize the use of the information obtained from Gabor filters, a computerized Monte Carlo simulation followed by ROC study is used to find the best nonlinear operator. The next stage of filtering process is to extract symmetrical parts in the stent. The global and local symmetry measures are used. The information gathered from previous two filter stages are used to generate a stent contour map. The contour map is then scaled and added back to the original image to get a contrast enhanced stent image. We also apply a spatio-temporal channelized Hotelling observer model and other numerical measures to characterize the response of the filters and contour map to optimize the selections of parameters for image quality. The results are compared to those filtered by an adaptive unsharp masking filter previously developed. It is shown that stent enhancement filter can effectively improve the stent detection and differentiation in the interventional fluoroscopy.

  12. The design and imaging characteristics of dynamic, solid-state, flat-panel x-ray image detectors for digital fluoroscopy and fluorography.

    PubMed

    Cowen, A R; Davies, A G; Sivananthan, M U

    2008-10-01

    Dynamic, flat-panel, solid-state, x-ray image detectors for use in digital fluoroscopy and fluorography emerged at the turn of the millennium. This new generation of dynamic detectors utilize a thin layer of x-ray absorptive material superimposed upon an electronic active matrix array fabricated in a film of hydrogenated amorphous silicon (a-Si:H). Dynamic solid-state detectors come in two basic designs, the indirect-conversion (x-ray scintillator based) and the direct-conversion (x-ray photoconductor based). This review explains the underlying principles and enabling technologies associated with these detector designs, and evaluates their physical imaging characteristics, comparing their performance against the long established x-ray image intensifier television (TV) system. Solid-state detectors afford a number of physical imaging benefits compared with the latter. These include zero geometrical distortion and vignetting, immunity from blooming at exposure highlights and negligible contrast loss (due to internal scatter). They also exhibit a wider dynamic range and maintain higher spatial resolution when imaging over larger fields of view. The detective quantum efficiency of indirect-conversion, dynamic, solid-state detectors is superior to that of both x-ray image intensifier TV systems and direct-conversion detectors. Dynamic solid-state detectors are playing a burgeoning role in fluoroscopy-guided diagnosis and intervention, leading to the displacement of x-ray image intensifier TV-based systems. Future trends in dynamic, solid-state, digital fluoroscopy detectors are also briefly considered. These include the growth in associated three-dimensional (3D) visualization techniques and potential improvements in dynamic detector design.

  13. Registration of 3D+t coronary CTA and monoplane 2D+t X-ray angiography.

    PubMed

    Metz, Coert T; Schaap, Michiel; Klein, Stefan; Baka, Nora; Neefjes, Lisan A; Schultz, Carl J; Niessen, Wiro J; van Walsum, Theo

    2013-05-01

    A method for registering preoperative 3D+t coronary CTA with intraoperative monoplane 2D+t X-ray angiography images is proposed to improve image guidance during minimally invasive coronary interventions. The method uses a patient-specific dynamic coronary model, which is derived from the CTA scan by centerline extraction and motion estimation. The dynamic coronary model is registered with the 2D+t X-ray sequence, considering multiple X-ray time points concurrently, while taking breathing induced motion into account. Evaluation was performed on 26 datasets of 17 patients by comparing projected model centerlines with manually annotated centerlines in the X-ray images. The proposed 3D+t/2D+t registration method performed better than a 3D/2D registration method with respect to the accuracy and especially the robustness of the registration. Registration with a median error of 1.47 mm was achieved.

  14. 2D electron temperature diagnostic using soft x-ray imaging technique

    SciTech Connect

    Nishimura, K. Sanpei, A. Tanaka, H.; Ishii, G.; Kodera, R.; Ueba, R.; Himura, H.; Masamune, S.; Ohdachi, S.; Mizuguchi, N.

    2014-03-15

    We have developed a two-dimensional (2D) electron temperature (T{sub e}) diagnostic system for thermal structure studies in a low-aspect-ratio reversed field pinch (RFP). The system consists of a soft x-ray (SXR) camera with two pin holes for two-kinds of absorber foils, combined with a high-speed camera. Two SXR images with almost the same viewing area are formed through different absorber foils on a single micro-channel plate (MCP). A 2D T{sub e} image can then be obtained by calculating the intensity ratio for each element of the images. We have succeeded in distinguishing T{sub e} image in quasi-single helicity (QSH) from that in multi-helicity (MH) RFP states, where the former is characterized by concentrated magnetic fluctuation spectrum and the latter, by broad spectrum of edge magnetic fluctuations.

  15. Registration of 2D x-ray images to 3D MRI by generating pseudo-CT data

    NASA Astrophysics Data System (ADS)

    van der Bom, M. J.; Pluim, J. P. W.; Gounis, M. J.; van de Kraats, E. B.; Sprinkhuizen, S. M.; Timmer, J.; Homan, R.; Bartels, L. W.

    2011-02-01

    Spatial and soft tissue information provided by magnetic resonance imaging can be very valuable during image-guided procedures, where usually only real-time two-dimensional (2D) x-ray images are available. Registration of 2D x-ray images to three-dimensional (3D) magnetic resonance imaging (MRI) data, acquired prior to the procedure, can provide optimal information to guide the procedure. However, registering x-ray images to MRI data is not a trivial task because of their fundamental difference in tissue contrast. This paper presents a technique that generates pseudo-computed tomography (CT) data from multi-spectral MRI acquisitions which is sufficiently similar to real CT data to enable registration of x-ray to MRI with comparable accuracy as registration of x-ray to CT. The method is based on a k-nearest-neighbors (kNN)-regression strategy which labels voxels of MRI data with CT Hounsfield Units. The regression method uses multi-spectral MRI intensities and intensity gradients as features to discriminate between various tissue types. The efficacy of using pseudo-CT data for registration of x-ray to MRI was tested on ex vivo animal data. 2D-3D registration experiments using CT and pseudo-CT data of multiple subjects were performed with a commonly used 2D-3D registration algorithm. On average, the median target registration error for registration of two x-ray images to MRI data was approximately 1 mm larger than for x-ray to CT registration. The authors have shown that pseudo-CT data generated from multi-spectral MRI facilitate registration of MRI to x-ray images. From the experiments it could be concluded that the accuracy achieved was comparable to that of registering x-ray images to CT data.

  16. Automatic localization of target vertebrae in spine surgery using fast CT-to-fluoroscopy (3D-2D) image registration

    NASA Astrophysics Data System (ADS)

    Otake, Y.; Schafer, S.; Stayman, J. W.; Zbijewski, W.; Kleinszig, G.; Graumann, R.; Khanna, A. J.; Siewerdsen, J. H.

    2012-02-01

    Localization of target vertebrae is an essential step in minimally invasive spine surgery, with conventional methods relying on "level counting" - i.e., manual counting of vertebrae under fluoroscopy starting from readily identifiable anatomy (e.g., the sacrum). The approach requires an undesirable level of radiation, time, and is prone to counting errors due to the similar appearance of vertebrae in projection images; wrong-level surgery occurs in 1 of every ~3000 cases. This paper proposes a method to automatically localize target vertebrae in x-ray projections using 3D-2D registration between preoperative CT (in which vertebrae are preoperatively labeled) and intraoperative fluoroscopy. The registration uses an intensity-based approach with a gradient-based similarity metric and the CMA-ES algorithm for optimization. Digitally reconstructed radiographs (DRRs) and a robust similarity metric are computed on GPU to accelerate the process. Evaluation in clinical CT data included 5,000 PA and LAT projections randomly perturbed to simulate human variability in setup of mobile intraoperative C-arm. The method demonstrated 100% success for PA view (projection error: 0.42mm) and 99.8% success for LAT view (projection error: 0.37mm). Initial implementation on GPU provided automatic target localization within about 3 sec, with further improvement underway via multi-GPU. The ability to automatically label vertebrae in fluoroscopy promises to streamline surgical workflow, improve patient safety, and reduce wrong-site surgeries, especially in large patients for whom manual methods are time consuming and error prone.

  17. Characterization of a 2D soft x-ray tomography camera with discrimination in energy bands

    SciTech Connect

    Romano, A.; Pacella, D.; Gabellieri, L.; Tilia, B.; Piergotti, V.; Mazon, D.; Malard, P.

    2010-10-15

    A gas detector with a 2D pixel readout is proposed for a future soft x-ray (SXR) tomography with discrimination in energy bands separately per pixel. The detector has three gas electron multiplier foils for the electron amplification and it offers the advantage, compared with the single stage, to be less sensitive to neutrons and gammas. The energy resolution and the detection efficiency of the detector have been accurately studied in the laboratory with continuous SXR spectra produced by an electronic tube and line emissions produced by fluorescence (K, Fe, and Mo) in the range of 3-17 keV. The front-end electronics, working in photon counting mode with a selectable threshold for pulse discrimination, is optimized for high rates. The distribution of the pulse amplitude has been indirectly derived by means of scans of the threshold. Scans in detector gain have also been performed to assess the capability of selecting different energy ranges.

  18. Performance of a static-anode/flat-panel x-ray fluoroscopy system in a diagnostic strength magnetic field: a truly hybrid x-ray/MR imaging system.

    PubMed

    Fahrig, R; Wen, Z; Ganguly, A; DeCrescenzo, G; Rowlands, J A; Stevens, G M; Saunders, R F; Pelc, N J

    2005-06-01

    Minimally invasive procedures are increasing in variety and frequency, facilitated by advances in imaging technology. Our hybrid imaging system (GE Apollo flat panel, custom Brand x-ray static anode x-ray tube, GE Lunar high-frequency power supply and 0.5 T Signa SP) provides both x-ray and MR imaging capability to guide complex procedures without requiring motion of the patient between two distant gantries. The performance of the x-ray tube in this closely integrated system was evaluated by modeling and measuring both the response of the filament to an externally applied field and the behavior of the electron beam for field strengths and geometries of interest. The performance of the detector was assessed by measuring the slanted-edge modulation transfer function (MTF) and when placed at zero field and at 0.5 T. Measured resonant frequencies of filaments can be approximated using a modified vibrating beam model, and were at frequencies well below the 25 kHz frequency of our generator for our filament geometry. The amplitude of vibration was not sufficient to cause shorting of the filament during operation within the magnetic field. A simple model of electrons in uniform electric and magnetic fields can be used to estimate the deflection of the electron beam on the anode for the fields of interest between 0.2 and 0.5 T. The MTF measured at the detector and the DQE showed no significant difference inside and outside of the magnetic field. With the proper modifications, an x-ray system can be fully integrated with a MR system, with minimal loss of image quality. Any x-ray tube can be assessed for compatibility when placed at a particular location within the field using the models. We have also concluded that a-Si electronics are robust against magnetic fields. Detailed knowledge of the x-ray system installation is required to provide estimates of system operation.

  19. 2D and 3D Refraction Based X-ray Imaging Suitable for Clinical and Pathological Diagnosis

    SciTech Connect

    Ando, Masami; Bando, Hiroko; Ueno, Ei

    2007-01-19

    The first observation of micro papillary (MP) breast cancer by x-ray dark-field imaging (XDFI) and the first observation of the 3D x-ray internal structure of another breast cancer, ductal carcinoma in-situ (DCIS), are reported. The specimen size for the sheet-shaped MP was 26 mm x 22 mm x 2.8 mm, and that for the rod-shaped DCIS was 3.6 mm in diameter and 4.7 mm in height. The experiment was performed at the Photon Factory, KEK: High Energy Accelerator Research Organization. We achieved a high-contrast x-ray image by adopting a thickness-controlled transmission-type angular analyzer that allows only refraction components from the object for 2D imaging. This provides a high-contrast image of cancer-cell nests, cancer cells and stroma. For x-ray 3D imaging, a new algorithm due to the refraction for x-ray CT was created. The angular information was acquired by x-ray optics diffraction-enhanced imaging (DEI). The number of data was 900 for each reconstruction. A reconstructed CT image may include ductus lactiferi, micro calcification and the breast gland. This modality has the possibility to open up a new clinical and pathological diagnosis using x-ray, offering more precise inspection and detection of early signs of breast cancer.

  20. Robust initialization for 2D/3D registration of knee implant models to single-plane fluoroscopy

    NASA Astrophysics Data System (ADS)

    Hermans, J.; Claes, P.; Bellemans, J.; Vandermeulen, D.; Suetens, P.

    2007-03-01

    A fully automated initialization method is proposed for the 2D/3D registration of 3D CAD models of knee implant components to a single-plane calibrated fluoroscopy. The algorithm matches edge segments, detected in the fluoroscopy image, with pre-computed libraries of expected 2D silhouettes of the implant components. Each library entry represents a different combination of out-of-plane registration transformation parameters. Library matching is performed by computing point-based 2D/2D registrations in between each library entry and each detected edge segment in the fluoroscopy image, resulting in an estimate of the in-plane registration transformation parameters. Point correspondences for registration are established by template matching of the bending patterns on the contours. A matching score for each individual 2D/2D registration is computed by evaluating the transformed library entry in an edge-encoded (characteristic) image, which is derived from the original fluoroscopy image. A matching scores accumulator is introduced to select and suggest one or more initial pose estimates. The proposed method is robust against occlusions and partial segmentations. Validation results are shown on simulated fluoroscopy images. In all cases a library match is found for each implant component which is very similar to the shape information in the fluoroscopy. The feasibility of the proposed method is demonstrated by initializing an intensity-based 2D/3D registration method with the automatically obtained estimation of the registration transformation parameters.

  1. An integrated system for 3D hip joint reconstruction from 2D X-rays: a preliminary validation study.

    PubMed

    Schumann, Steffen; Liu, Li; Tannast, Moritz; Bergmann, Mathias; Nolte, Lutz-P; Zheng, Guoyan

    2013-10-01

    The acquisition of conventional X-ray radiographs remains the standard imaging procedure for the diagnosis of hip-related problems. However, recent studies demonstrated the benefit of using three-dimensional (3D) surface models in the clinical routine. 3D surface models of the hip joint are useful for assessing the dynamic range of motion in order to identify possible pathologies such as femoroacetabular impingement. In this paper, we present an integrated system which consists of X-ray radiograph calibration and subsequent 2D/3D hip joint reconstruction for diagnosis and planning of hip-related problems. A mobile phantom with two different sizes of fiducials was developed for X-ray radiograph calibration, which can be robustly detected within the images. On the basis of the calibrated X-ray images, a 3D reconstruction method of the acetabulum was developed and applied together with existing techniques to reconstruct a 3D surface model of the hip joint. X-ray radiographs of dry cadaveric hip bones and one cadaveric specimen with soft tissue were used to prove the robustness of the developed fiducial detection algorithm. Computed tomography scans of the cadaveric bones were used to validate the accuracy of the integrated system. The fiducial detection sensitivity was in the same range for both sizes of fiducials. While the detection sensitivity was 97.96% for the large fiducials, it was 97.62% for the small fiducials. The acetabulum and the proximal femur were reconstructed with a mean surface distance error of 1.06 and 1.01 mm, respectively. The results for fiducial detection sensitivity and 3D surface reconstruction demonstrated the capability of the integrated system for 3D hip joint reconstruction from 2D calibrated X-ray radiographs.

  2. Twin robotic x-ray system for 2D radiographic and 3D cone-beam CT imaging

    NASA Astrophysics Data System (ADS)

    Fieselmann, Andreas; Steinbrener, Jan; Jerebko, Anna K.; Voigt, Johannes M.; Scholz, Rosemarie; Ritschl, Ludwig; Mertelmeier, Thomas

    2016-03-01

    In this work, we provide an initial characterization of a novel twin robotic X-ray system. This system is equipped with two motor-driven telescopic arms carrying X-ray tube and flat-panel detector, respectively. 2D radiographs and fluoroscopic image sequences can be obtained from different viewing angles. Projection data for 3D cone-beam CT reconstruction can be acquired during simultaneous movement of the arms along dedicated scanning trajectories. We provide an initial evaluation of the 3D image quality based on phantom scans and clinical images. Furthermore, initial evaluation of patient dose is conducted. The results show that the system delivers high image quality for a range of medical applications. In particular, high spatial resolution enables adequate visualization of bone structures. This system allows 3D X-ray scanning of patients in standing and weight-bearing position. It could enable new 2D/3D imaging workflows in musculoskeletal imaging and improve diagnosis of musculoskeletal disorders.

  3. 2D and 3D Terahertz Imaging and X-Rays CT for Sigillography Study

    NASA Astrophysics Data System (ADS)

    Fabre, M.; Durand, R.; Bassel, L.; Recur, B.; Balacey, H.; Bou Sleiman, J.; Perraud, J.-B.; Mounaix, P.

    2017-04-01

    Seals are part of our cultural heritage but the study of these objects is limited because of their fragility. Terahertz and X-Ray imaging are used to analyze a collection of wax seals from the fourteenth to eighteenth centuries. In this work, both techniques are compared in order to discuss their advantages and limits and their complementarity for conservation state study of the samples. Thanks to 3D analysis and reconstructions, defects and fractures are detected with an estimation of their depth position. The path from the parchment tongue inside the seals is also detected.

  4. 2D and 3D Terahertz Imaging and X-Rays CT for Sigillography Study

    NASA Astrophysics Data System (ADS)

    Fabre, M.; Durand, R.; Bassel, L.; Recur, B.; Balacey, H.; Bou Sleiman, J.; Perraud, J.-B.; Mounaix, P.

    2017-01-01

    Seals are part of our cultural heritage but the study of these objects is limited because of their fragility. Terahertz and X-Ray imaging are used to analyze a collection of wax seals from the fourteenth to eighteenth centuries. In this work, both techniques are compared in order to discuss their advantages and limits and their complementarity for conservation state study of the samples. Thanks to 3D analysis and reconstructions, defects and fractures are detected with an estimation of their depth position. The path from the parchment tongue inside the seals is also detected.

  5. 2D-Omnidirectional Hard-X-Ray Scattering Sensitivity in a Single Shot

    NASA Astrophysics Data System (ADS)

    Kagias, Matias; Wang, Zhentian; Villanueva-Perez, Pablo; Jefimovs, Konstantins; Stampanoni, Marco

    2016-03-01

    X-ray scattering imaging can provide complementary information to conventional absorption based radiographic imaging about the unresolved microstructures of a sample. The scattering signal can be accessed with various methods based on coherent illumination, which span from self-imaging to speckle scanning. The directional sensitivity of the existing real space imaging methods is limited to a few directions on the imaging plane and requires scanning of the optical components, or the rotation of either the sample or the imaging setup, in order to cover the full range of possible scattering directions. In this Letter the authors propose a new method that allows the simultaneous acquisition of scattering images in all possible directions in a single shot. This is achieved by a specialized phase grating and a detector with sufficient spatial resolution to record the generated interference fringe. The structural length scale sensitivity of the system can be tuned by varying its geometry for a fixed grating design. Taking into account ongoing developments in the field of compact x-ray sources that allow high brightness and sufficient spatial coherence, the applicability of omnidirectional scattering imaging in industrial and medical settings is boosted significantly.

  6. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy

    NASA Astrophysics Data System (ADS)

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-01

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  7. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy.

    PubMed

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-21

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  8. 2D X-ray radiography of imploding capsules at the national ignition facility.

    PubMed

    Rygg, J R; Jones, O S; Field, J E; Barrios, M A; Benedetti, L R; Collins, G W; Eder, D C; Edwards, M J; Kline, J L; Kroll, J J; Landen, O L; Ma, T; Pak, A; Peterson, J L; Raman, K; Town, R P J; Bradley, D K

    2014-05-16

    First measurements of the in-flight shape of imploding inertial confinement fusion (ICF) capsules at the National Ignition Facility (NIF) were obtained by using two-dimensional x-ray radiography. The sequence of area-backlit, time-gated pinhole images is analyzed for implosion velocity, low-mode shape and density asymmetries, and the absolute offset and center-of-mass velocity of the capsule shell. The in-flight shell is often observed to be asymmetric even when the concomitant core self-emission is round. A ∼ 15 μm shell asymmetry amplitude of the Y(40) spherical harmonic mode was observed for standard NIF ICF hohlraums at a shell radius of ∼ 200 μm (capsule at ∼ 5× radial compression). This asymmetry is mitigated by a ∼ 10% increase in the hohlraum length.

  9. A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging.

    PubMed

    Gallio, Elena; Rampado, Osvaldo; Gianaria, Elena; Bianchi, Silvio Diego; Ropolo, Roberto

    2015-01-01

    Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies.

  10. A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging

    PubMed Central

    Gallio, Elena; Rampado, Osvaldo; Gianaria, Elena; Bianchi, Silvio Diego; Ropolo, Roberto

    2015-01-01

    Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies. PMID:26545097

  11. Magnetically Assisted Remote-controlled Endovascular Catheter for Interventional MR Imaging: In Vitro Navigation at 1.5 T versus X-ray Fluoroscopy

    PubMed Central

    Losey, Aaron D.; Lillaney, Prasheel; Martin, Alastair J.; Cooke, Daniel L.; Wilson, Mark W.; Thorne, Bradford R. H.; Sincic, Ryan S.; Arenson, Ronald L.; Saeed, Maythem

    2014-01-01

    Purpose To compare in vitro navigation of a magnetically assisted remote-controlled (MARC) catheter under real-time magnetic resonance (MR) imaging with manual navigation under MR imaging and standard x-ray guidance in endovascular catheterization procedures in an abdominal aortic phantom. Materials and Methods The 2-mm-diameter custom clinical-grade microcatheter prototype with a solenoid coil at the distal tip was deflected with a foot pedal actuator used to deliver 300 mA of positive or negative current. Investigators navigated the catheter into branch vessels in a custom cryogel abdominal aortic phantom. This was repeated under MR imaging guidance without magnetic assistance and under conventional x-ray fluoroscopy. MR experiments were performed at 1.5 T by using a balanced steady-state free precession sequence. The mean procedure times and percentage success data were determined and analyzed with a linear mixed-effects regression analysis. Results The catheter was clearly visible under real-time MR imaging. One hundred ninety-two (80%) of 240 turns were successfully completed with magnetically assisted guidance versus 144 (60%) of 240 turns with nonassisted guidance (P < .001) and 119 (74%) of 160 turns with standard x-ray guidance (P = .028). Overall mean procedure time was shorter with magnetically assisted than with nonassisted guidance under MR imaging (37 seconds ± 6 [standard error of the mean] vs 55 seconds ± 3, P < .001), and time was comparable between magnetically assisted and standard x-ray guidance (37 seconds ± 6 vs 44 seconds ± 3, P = .045). When stratified by angle of branch vessel, magnetic assistance was faster than nonassisted MR guidance at turns of 45°, 60°, and 75°. Conclusion In this study, a MARC catheter for endovascular navigation under real-time MR imaging guidance was developed and tested. For catheterization of branch vessels arising at large angles, magnetically assisted catheterization was faster than manual catheterization

  12. Molar concentration from sequential 2-D water-window X-ray ptychography and X-ray fluorescence in hydrated cells

    PubMed Central

    Jones, M. W. M.; Elgass, K. D.; Junker, M. D.; de Jonge, M. D.; van Riessen, G. A.

    2016-01-01

    Recent developments in biological X-ray microscopy have allowed structural information and elemental distribution to be simultaneously obtained by combining X-ray ptychography and X-ray fluorescence microscopy. Experimentally, these methods can be performed simultaneously; however, the optimal conditions for each measurement may not be compatible. Here, we combine two distinct measurements of ultrastructure and elemental distribution, with each measurement performed under optimised conditions. By combining optimised ptychography and fluorescence information we are able to determine molar concentrations from two-dimensional images, allowing an investigation into the interactions between the environment sensing filopodia in fibroblasts and extracellular calcium. Furthermore, the biological ptychography results we present illustrate a point of maturity where the technique can be applied to solve significant problems in structural biology. PMID:27067957

  13. Coherent X-ray beam metrology using 2D high-resolution Fresnel-diffraction analysis.

    PubMed

    Ruiz-Lopez, M; Faenov, A; Pikuz, T; Ozaki, N; Mitrofanov, A; Albertazzi, B; Hartley, N; Matsuoka, T; Ochante, Y; Tange, Y; Yabuuchi, T; Habara, T; Tanaka, K A; Inubushi, Y; Yabashi, M; Nishikino, M; Kawachi, T; Pikuz, S; Ishikawa, T; Kodama, R; Bleiner, D

    2017-01-01

    Direct metrology of coherent short-wavelength beamlines is important for obtaining operational beam characteristics at the experimental site. However, since beam-time limitation imposes fast metrology procedures, a multi-parametric metrology from as low as a single shot is desirable. Here a two-dimensional (2D) procedure based on high-resolution Fresnel diffraction analysis is discussed and applied, which allowed an efficient and detailed beamline characterization at the SACLA XFEL. So far, the potential of Fresnel diffraction for beamline metrology has not been fully exploited because its high-frequency fringes could be only partly resolved with ordinary pixel-limited detectors. Using the high-spatial-frequency imaging capability of an irradiated LiF crystal, 2D information of the coherence degree, beam divergence and beam quality factor M(2) were retrieved from simple diffraction patterns. The developed beam metrology was validated with a laboratory reference laser, and then successfully applied at a beamline facility, in agreement with the source specifications.

  14. Coronary arteries motion modeling on 2D x-ray images

    NASA Astrophysics Data System (ADS)

    Gao, Yang; Sundar, Hari

    2012-02-01

    During interventional procedures, 3D imaging modalities like CT and MRI are not commonly used due to interference with the surgery and radiation exposure concerns. Therefore, real-time information is usually limited and building models of cardiac motion are difficult. In such case, vessel motion modeling based on 2-D angiography images become indispensable. Due to issues with existing vessel segmentation algorithms and the lack of contrast in occluded vessels, manual segmentation of certain branches is usually necessary. In addition, such occluded branches are the most important vessels during coronary interventions and obtaining motion models for these can greatly help in reducing the procedure time and radiation exposure. Segmenting different cardiac phases independently does not guarantee temporal consistency and is not efficient for occluded branches required manual segmentation. In this paper, we propose a coronary motion modeling system which extracts the coronary tree for every cardiac phase, maintaining the segmentation by tracking the coronary tree during the cardiac cycle. It is able to map every frame to the specific cardiac phase, thereby inferring the shape information of the coronary arteries using the model corresponding to its phase. Our experiments show that our motion modeling system can achieve promising results with real-time performance.

  15. Quantitative comparison of dose distribution in radiotherapy plans using 2D gamma maps and X-ray computed tomography

    PubMed Central

    Balosso, Jacques

    2016-01-01

    Background The advanced dose calculation algorithms implemented in treatment planning system (TPS) have remarkably improved the accuracy of dose calculation especially the modeling of electrons transport in the low density medium. The purpose of this study is to evaluate the use of 2D gamma (γ) index to quantify and evaluate the impact of the calculation of electrons transport on dose distribution for lung radiotherapy. Methods X-ray computed tomography images were used to calculate the dose for twelve radiotherapy treatment plans. The doses were originally calculated with Modified Batho (MB) 1D density correction method, and recalculated with anisotropic analytical algorithm (AAA), using the same prescribed dose. Dose parameters derived from dose volume histograms (DVH) and target coverage indices were compared. To compare dose distribution, 2D γ-index was applied, ranging from 1%/1 mm to 6%/6 mm. The results were displayed using γ-maps in 2D. Correlation between DVH metrics and γ passing rates was tested using Spearman’s rank test and Wilcoxon paired test to calculate P values. Results the plans generated with AAA predicted more heterogeneous dose distribution inside the target, with P<0.05. However, MB overestimated the dose predicting more coverage of the target by the prescribed dose. The γ analysis showed that the difference between MB and AAA could reach up to ±10%. The 2D γ-maps illustrated that AAA predicted more dose to organs at risks, as well as lower dose to the target compared to MB. Conclusions Taking into account of the electrons transport on radiotherapy plans showed a significant impact on delivered dose and dose distribution. When considering the AAA represent the true cumulative dose, a readjusting of the prescribed dose and an optimization to protect the organs at risks should be taken in consideration in order to obtain the better clinical outcome. PMID:27429908

  16. Lateral elasticity and X-ray diffraction of protein 2D crystals bound to lipid monolayers at the water surface.

    NASA Astrophysics Data System (ADS)

    Lenne, P. F.; Berge, B.; Renault, A.; Vénien-Bryan, C.; Courty, S.; Konovalov, O.; Legrand, J. F.; Brisson, A.; Balavoine, F.; Lal, J.; Gruebel, G.

    1998-03-01

    We present high resolution X-ray grazing incidence diffraction experiments and macroscopic lateral rigidity measurements performed on two-dimensional crystals of proteins bound to lipid monolayers at the water surface. For four different protein systems, Streptavidin bound to biotinylated lipids, an hystidin-tagged transcription factor HupR bound to Nickel lipids, Annexin-V bound to PS and Cholera toxin subunit-B bound to GM1 lipids, we record a non-zero shear elastic constant. For the three first systems, we observe narrow diffraction peaks and measure the Bragg rods intensities. In the case of Streptavidin we found two different possible structures, one of them exhibiting 19 Bragg rods, diffracting at about 10Åin the plane. After injecting glutaraldehyde (a protein linker) under the already formed 2D-crystals, the shear rigidity increases by a factor of two and additional diffraction peaks appear. This illustrates the correlation between the macroscopic shear elastic constant and the maximum in-plane wave vector transfer of the diffraction pattern, as expected in two dimensions. It also shows the interest of keeping the 2D-crystal in the water for subsequent action of various agents.

  17. Progress in electron-multiplying CCD (EMCCD) based high-resolution high-sensitivity x-ray detector for fluoroscopy and radiography

    NASA Astrophysics Data System (ADS)

    Kuhls, Andrew T.; Yadava, Girijesh; Patel, Vikas; Bednarek, Daniel R.; Rudin, Stephen

    2007-03-01

    A new high-resolution, high-sensitivity, low-noise x-ray detector based on EMCCDs has been developed. The EMCCD detector module consists of a 1kx1k, 8μm pixel EMCCD camera coupled to a CsI(Tl) scintillating phosphor via a fiber optic taper (FOT). Multiple modules can be used to provide the desired field-of-view (FOV). The detector is capable of acquisitions over 30fps. The EMCCD's variable gain of up to 2000x for the pixel signal enables high sensitivity for fluoroscopic applications. With a 3:1 FOT, the detector can operate with a 144μm effective pixel size, comparable to current flat-panel detectors. Higher resolutions of 96 and 48μm pixel size can also be achieved with various binning modes. The detector MTFs and DQEs were calculated using a linear-systems analysis. The zero frequency DQE was calculated to be 59% at 74 kVp. The DQE for the 144μm pixel size was shown to exhibit quantum-noise limited behavior down to ~0.1μR using a conservative 30x gain. At this low exposure, gains above 30x showed limited improvements in DQE suggesting such increased gains may not be necessary. For operation down to 48µm pixel sizes, the detector instrumentation noise equivalent exposure (INEE), defined as the exposure where the instrumentation noise equals the quantum-noise, was <0.1μR for a 20x gain. This new technology may provide improvements over current flat-panel detectors for applications such as fluoroscopy and angiography requiring high frame rates, resolution, dynamic range and sensitivity while maintaining essentially no lag and very low INEE. Initial images from a prototype detector are also presented.

  18. Doppler Tomography in 2D and 3D of the X-ray Binary Cyg X-1 for June 2007

    NASA Astrophysics Data System (ADS)

    Sharova, O. I.; Agafonov, M. I.; Karitskaya, E. A.; Bochkarev, N. G.; Zharikov, S. V.; Butenko, G. Z.; Bondar, A. V.

    2012-04-01

    The 2D and 3D Doppler tomograms of X-ray binary system Cyg X-1 (V1357 Cyg) were reconstructed from spectral data for the line HeII 4686Å obtained with 2-m telescope of the Peak Terskol Observatory (Russia) and 2.1-m telescope of the Mexican National Observatory in June, 2007. Information about gas motions outside the orbital plane, using all of the three velocity components Vx, Vy, Vz, was obtained for the first time. The tomographic reconstruction was carried out for the system inclination angle of 45°. The equal resolution (50 × 50 × 50 km/s) is realized in this case, in the orbital plane (Vx, Vy) and also in the perpendicular direction Vz. The checkout tomograms were realized also for the inclination angle of 40° because of the angle uncertainty. Two versions of the result showed no qualitative discrepancy. Details of the structures revealed by the 3D Doppler tomogram were analyzed.

  19. Calibration model of a dual gain flat panel detector for 2D and 3D x-ray imaging

    SciTech Connect

    Schmidgunst, C.; Ritter, D.; Lang, E.

    2007-09-15

    The continuing research and further development in flat panel detector technology have led to its integration into more and more medical x-ray systems for two-dimensional (2D) and three-dimensional (3D) imaging, such as fixed or mobile C arms. Besides the obvious advantages of flat panel detectors, like the slim design and the resulting optimum accessibility to the patient, their success is primarily a product of the image quality that can be achieved. The benefits in the physical and performance-related features as opposed to conventional image intensifier systems (e.g., distortion-free reproduction of imaging information or almost linear signal response over a large dynamic range) can be fully exploited, however, only if the raw detector images are correctly calibrated and postprocessed. Previous procedures for processing raw data contain idealizations that, in the real world, lead to artifacts or losses in image quality. Thus, for example, temperature dependencies or changes in beam geometry, as can occur with mobile C arm systems, have not been taken into account up to this time. Additionally, adverse characteristics such as image lag or aging effects have to be compensated to attain the best possible image quality. In this article a procedure is presented that takes into account the important dependencies of the individual pixel sensitivity of flat panel detectors used in 2D or 3D imaging and simultaneously minimizes the work required for an extensive recalibration. It is suitable for conventional detectors with only one gain mode as well as for the detectors specially developed for 3D imaging with dual gain read-out technology.

  20. Calibration model of a dual gain flat panel detector for 2D and 3D x-ray imaging.

    PubMed

    Schmidgunst, C; Ritter, D; Lang, E

    2007-09-01

    The continuing research and further development in flat panel detector technology have led to its integration into more and more medical x-ray systems for two-dimensional (2D) and three-dimensional (3D) imaging, such as fixed or mobile C arms. Besides the obvious advantages of flat panel detectors, like the slim design and the resulting optimum accessibility to the patient, their success is primarily a product of the image quality that can be achieved. The benefits in the physical and performance-related features as opposed to conventional image intensifier systems, (e.g., distortion-free reproduction of imaging information or almost linear signal response over a large dynamic range) can be fully exploited, however, only if the raw detector images are correctly calibrated and postprocessed. Previous procedures for processing raw data contain idealizations that, in the real world, lead to artifacts or losses in image quality. Thus, for example, temperature dependencies or changes in beam geometry, as can occur with mobile C arm systems, have not been taken into account up to this time. Additionally, adverse characteristics such as image lag or aging effects have to be compensated to attain the best possible image quality. In this article a procedure is presented that takes into account the important dependencies of the individual pixel sensitivity of flat panel detectors used in 2D or 3D imaging and simultaneously minimizes the work required for an extensive recalibration. It is suitable for conventional detectors with only one gain mode as well as for the detectors specially developed for 3D imaging with dual gain read-out technology.

  1. A novel technique for single-shot energy-resolved 2D x-ray imaging of plasmas relevant for the inertial confinement fusion.

    PubMed

    Labate, L; Köster, P; Levato, T; Gizzi, L A

    2012-10-01

    A novel x-ray diagnostic of laser-fusion plasmas is described, allowing 2D monochromatic images of hot, dense plasmas to be obtained in any x-ray photon energy range, over a large domain, on a single-shot basis. The device (named energy-encoded pinhole camera) is based upon the use of an array of many pinholes coupled to a large area CCD camera operating in the single-photon mode. The available x-ray spectral domain is only limited by the quantum efficiency of scientific-grade x-ray CCD cameras, thus extending from a few keV up to a few tens of keV. Spectral 2D images of the emitting plasma can be obtained at any x-ray photon energy provided that a sufficient number of photons had been collected at the desired energy. Results from recent inertial confinement fusion related experiments will be reported in order to detail the new diagnostic.

  2. Integrating 2-D position sensitive X-ray detectors with low-density alkali halide storage targets

    NASA Astrophysics Data System (ADS)

    Haubold, H.-G.; Hoheisel, W.; Hiller, P.

    1986-05-01

    For the use in scattering experiments with synchrotron radiation, integrating position sensitive X-ray detectors are discussed. These detectors store the photon number equivalent charge (PNEC) in low-density alkali halide targets. Performance tests are given for a detector which uses a Gd 2O 2S fluorescence screen for X-ray detection and the low-density KCl storage target of a television SEC vidicon tube for photon integration. Rather than directly by X-rays, this target is charged by 6 keV electrons from the image intensifier section of the vidicon. Its excellent storage capability allows measurements of extremely high-contrast, high-flux X-ray patterns with the same accuracy as achieved with any single photon detection system if the discussed readout techniques are applied.

  3. New-Generation Laser-lithographed Dual-Axis Magnetically Assisted Remote-controlled Endovascular Catheter for Interventional MR Imaging: In Vitro Multiplanar Navigation at 1.5 T and 3 T versus X-ray Fluoroscopy

    PubMed Central

    Moftakhar, Parham; Lillaney, Prasheel; Losey, Aaron D.; Cooke, Daniel L.; Martin, Alastair J.; Thorne, Bradford R. H.; Arenson, Ronald L.; Saeed, Maythem; Wilson, Mark W.

    2015-01-01

    Purpose To assess the feasibility of multiplanar vascular navigation with a new magnetically assisted remote-controlled (MARC) catheter with real-time magnetic resonance (MR) imaging at 1.5 T and 3 T and to compare it with standard x-ray guidance in simulated endovascular catheterization procedures. Materials and Methods A 1.6-mm–diameter custom clinical-grade microcatheter prototype with lithographed double-saddle coils at the distal tip was deflected with real-time MR imaging. Two inexperienced operators and two experienced operators catheterized anteroposterior (celiac, superior mesenteric, and inferior mesenteric arteries) and mediolateral (renal arteries) branch vessels in a cryogel abdominal aortic phantom. This was repeated with conventional x-ray fluoroscopy by using clinical catheters and guidewires. Mean procedure times and percentage success data were analyzed with linear mixed-effects regression. Results The MARC catheter tip was visible at 1.5 T and 3 T. Among inexperienced operators, MARC MR imaging guidance was not statistically different from x-ray guidance at 1.5 T (67% successful vessel selection turns with MR imaging vs 76% with x-ray guidance, P = .157) and at 3 T (75% successful turns with MR imaging vs 76% with x-ray guidance, P = .869). Experienced operators were more successful in catheterizing vessels with x-ray guidance (98% success within 60 seconds) than with 1.5-T (65%, P < .001) or 3-T (75%) MR imaging. Among inexperienced operators, mean procedure time was nearly equivalent by using MR imaging (31 seconds) and x-ray guidance (34 seconds, P = .436). Among experienced operators, catheterization was faster with x-ray guidance (20 seconds) compared with 1.5-T MR imaging (42 seconds, P < .001), but MARC guidance improved at 3 T (31 seconds). MARC MR imaging guidance at 3 T was not significantly different from x-ray guidance for the celiac (P = .755), superior mesenteric (P = .358), and inferior mesenteric (P = .065) arteries. Conclusion

  4. 2D/3D cryo x-ray fluorescence imaging at the bionanoprobe at the advanced photon source

    SciTech Connect

    Chen, S. Vine, D. J.; Lai, B.; Paunesku, T.; Yuan, Y.; Woloschak, G. E.; Deng, J.; Jin, Q.; Hong, Y. P.; Flachenecker, C.; Hornberger, B.; Brister, K.; Jacobsen, C.; Vogt, S.

    2016-01-28

    Trace elements, particularly metals, play very important roles in biological systems. Synchrotron-based hard X-ray fluorescence microscopy offers the most suitable capabilities to quantitatively study trace metals in thick biological samples, such as whole cells and tissues. In this manuscript, we have demonstrated X-ray fluorescence imaging of frozen-hydrated whole cells using the recent developed Bionanoprobe (BNP). The BNP provides spatial resolution down to 30 nm and cryogenic capabilities. Frozen-hydrated biological cells have been directly examined on a sub-cellular level at liquid nitrogen temperatures with minimal sample preparation.

  5. Identifying the third dimension in 2D fluoroscopy to create 3D cardiac maps

    PubMed Central

    Krum, David; Choudhuri, Indrajit; Belanger, Barry; Palma, Mark; Brodnick, Donald; Rowe, Daniel B.

    2016-01-01

    Three-dimensional cardiac mapping is important for optimal visualization of the heart during cardiac ablation for the treatment of certain arrhythmias. However, many hospitals and clinics worldwide cannot afford the high cost of the current mapping systems. We set out to determine if, using predefined algorithms, comparable 3D cardiac maps could be created by a new device that relies on data generated from single-plane fluoroscopy and patient recording and monitoring systems, without the need for costly equipment, infrastructure changes, or specialized catheters. The study included phantom and animal experiments to compare the prototype test device, Navik 3D, with the existing CARTO 3 System. The primary endpoint directly compared: (a) the 3D distance between the Navik 3D–simulated ablation location and the back-projected ground truth location of the pacing and mapping catheter electrode, and (b) the same distance for CARTO. The study’s primary objective was considered met if the 95% confidence lower limit was greater than 0.75% for the Navik 3D–CARTO difference between the 2 distances, or less than or equal to 2 mm. Study results showed that the Navik 3D performance was equivalent to the CARTO system, and that accurate 3D cardiac maps can be created using data from equipment that already exists in all electrophysiology labs. PMID:28018976

  6. Identifying the third dimension in 2D fluoroscopy to create 3D cardiac maps.

    PubMed

    Sra, Jasbir; Krum, David; Choudhuri, Indrajit; Belanger, Barry; Palma, Mark; Brodnick, Donald; Rowe, Daniel B

    2016-12-22

    Three-dimensional cardiac mapping is important for optimal visualization of the heart during cardiac ablation for the treatment of certain arrhythmias. However, many hospitals and clinics worldwide cannot afford the high cost of the current mapping systems. We set out to determine if, using predefined algorithms, comparable 3D cardiac maps could be created by a new device that relies on data generated from single-plane fluoroscopy and patient recording and monitoring systems, without the need for costly equipment, infrastructure changes, or specialized catheters. The study included phantom and animal experiments to compare the prototype test device, Navik 3D, with the existing CARTO 3 System. The primary endpoint directly compared: (a) the 3D distance between the Navik 3D-simulated ablation location and the back-projected ground truth location of the pacing and mapping catheter electrode, and (b) the same distance for CARTO. The study's primary objective was considered met if the 95% confidence lower limit was greater than 0.75% for the Navik 3D-CARTO difference between the 2 distances, or less than or equal to 2 mm. Study results showed that the Navik 3D performance was equivalent to the CARTO system, and that accurate 3D cardiac maps can be created using data from equipment that already exists in all electrophysiology labs.

  7. 2D X-ray and FTIR micro-analysis of the degradation of cadmium yellow pigment in paintings of Henri Matisse

    NASA Astrophysics Data System (ADS)

    Pouyet, E.; Cotte, M.; Fayard, B.; Salomé, M.; Meirer, F.; Mehta, A.; Uffelman, E. S.; Hull, A.; Vanmeert, F.; Kieffer, J.; Burghammer, M.; Janssens, K.; Sette, F.; Mass, J.

    2015-11-01

    The chemical and physical alterations of cadmium yellow (CdS) paints in Henri Matisse's The Joy of Life (1905-1906, The Barnes Foundation) have been recognized since 2006, when a survey by portable X-ray fluorescence identified this pigment in all altered regions of the monumental painting. This alteration is visible as fading, discoloration, chalking, flaking, and spalling of several regions of light to medium yellow paint. Since that time, synchrotron radiation-based techniques including elemental and spectroscopic imaging, as well as X-ray scattering have been employed to locate and identify the alteration products observed in this and related works by Henri Matisse. This information is necessary to formulate one or multiple mechanisms for degradation of Matisse's paints from this period, and thus ensure proper environmental conditions for the storage and the display of his works. This paper focuses on 2D full-field X-ray Near Edge Structure imaging, 2D micro-X-ray Diffraction, X-ray Fluorescence, and Fourier Transform Infra-red imaging of the altered paint layers to address one of the long-standing questions about cadmium yellow alteration—the roles of cadmium carbonates and cadmium sulphates found in the altered paint layers. These compounds have often been assumed to be photo-oxidation products, but could also be residual starting reagents from an indirect wet process synthesis of CdS. The data presented here allow identifying and mapping the location of cadmium carbonates, cadmium chlorides, cadmium oxalates, cadmium sulphates, and cadmium sulphides in thin sections of altered cadmium yellow paints from The Joy of Life and Matisse's Flower Piece (1906, The Barnes Foundation). Distribution of various cadmium compounds confirms that cadmium carbonates and sulphates are photo-degradation products in The Joy of Life, whereas in Flower Piece, cadmium carbonates appear to have been a [(partially) unreacted] starting reagent for the yellow paint, a role

  8. Effects of x-ray and CT image enhancements on the robustness and accuracy of a rigid 3D/2D image registration.

    PubMed

    Kim, Jinkoo; Yin, Fang-Fang; Zhao, Yang; Kim, Jae Ho

    2005-04-01

    A rigid body three-dimensional/two-dimensional (3D/2D) registration method has been implemented using mutual information, gradient ascent, and 3D texturemap-based digitally reconstructed radiographs. Nine combinations of commonly used x-ray and computed tomography (CT) image enhancement methods, including window leveling, histogram equalization, and adaptive histogram equalization, were examined to assess their effects on accuracy and robustness of the registration method. From a set of experiments using an anthropomorphic chest phantom, we were able to draw several conclusions. First, the CT and x-ray preprocessing combination with the widest attraction range was the one that linearly stretched the histograms onto the entire display range on both CT and x-ray images. The average attraction ranges of this combination were 71.3 mm and 61.3 deg in the translation and rotation dimensions, respectively, and the average errors were 0.12 deg and 0.47 mm. Second, the combination of the CT image with tissue and bone information and the x-ray images with adaptive histogram equalization also showed subvoxel accuracy, especially the best in the translation dimensions. However, its attraction ranges were the smallest among the examined combinations (on average 36 mm and 19 deg). Last the bone-only information on the CT image did not show convergency property to the correct registration.

  9. Effective incorporation of spatial information in a mutual information based 3D-2D registration of a CT volume to X-ray images.

    PubMed

    Zheng, Guoyan

    2008-01-01

    This paper addresses the problem of estimating the 3D rigid pose of a CT volume of an object from its 2D X-ray projections. We use maximization of mutual information, an accurate similarity measure for multi-modal and mono-modal image registration tasks. However, it is known that the standard mutual information measure only takes intensity values into account without considering spatial information and its robustness is questionable. In this paper, instead of directly maximizing mutual information, we propose to use a variational approximation derived from the Kullback-Leibler bound. Spatial information is then incorporated into this variational approximation using a Markov random field model. The newly derived similarity measure has a least-squares form and can be effectively minimized by a multi-resolution Levenberg-Marquardt optimizer. Experimental results are presented on X-ray and CT datasets of a plastic phantom and a cadaveric spine segment.

  10. RixsToolBox: software for the analysis of soft X-ray RIXS data acquired with 2D detectors.

    PubMed

    Kummer, K; Tamborrino, A; Amorese, A; Minola, M; Braicovich, L; Brookes, N B; Ghiringhelli, G

    2017-03-01

    A software with a graphical user interface has been developed with the aim of facilitating the data analysis for users of a new resonant inelastic X-ray scattering (RIXS) spectrometer installed at the ESRF beamline ID32. The software is organized in modules covering all relevant steps in the data reduction from a stack of several hundred two-dimensional CCD images to a single RIXS spectrum. It utilizes both full charge integration and single-photon centroiding to cope with high-flux and high-resolution requirements. Additional modules for further data analysis and the extraction of instrumental parameters are available. The software has been in routine use for about a year now and in that time many additional features have been incorporated. It now meets the users' need for an easy-to-use data analysis tool that allows looking at and understanding data as it is acquired and thus steering users' experiments more efficiently.

  11. Effective incorporating spatial information in a mutual information based 3D-2D registration of a CT volume to X-ray images.

    PubMed

    Zheng, Guoyan

    2010-10-01

    This paper addresses the problem of estimating the 3D rigid poses of a CT volume of an object from its 2D X-ray projection(s). We use maximization of mutual information, an accurate similarity measure for multi-modal and mono-modal image registration tasks. However, it is known that the standard mutual information measures only take intensity values into account without considering spatial information and their robustness is questionable. In this paper, instead of directly maximizing mutual information, we propose to use a variational approximation derived from the Kullback-Leibler bound. Spatial information is then incorporated into this variational approximation using a Markov random field model. The newly derived similarity measure has a least-squares form and can be effectively minimized by a multi-resolution Levenberg-Marquardt optimizer. Experiments were conducted on datasets from two applications: (a) intra-operative patient pose estimation from a limited number (e.g. 2) of calibrated fluoroscopic images, and (b) post-operative cup orientation estimation from a single standard X-ray radiograph with/without gonadal shielding. The experiment on intra-operative patient pose estimation showed a mean target registration accuracy of 0.8mm and a capture range of 11.5mm, while the experiment on estimating the post-operative cup orientation from a single X-ray radiograph showed a mean accuracy below 2 degrees for both anteversion and inclination. More importantly, results from both experiments demonstrated that the newly derived similarity measures were robust to occlusions in the X-ray image(s).

  12. The 2dF Galaxy Redshift Survey: correlation with the ROSAT-ESO flux-limited X-ray galaxy cluster survey

    NASA Astrophysics Data System (ADS)

    Hilton, Matt; Collins, Chris; De Propris, Roberto; Baldry, Ivan K.; Baugh, Carlton M.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Cole, Shaun; Colless, Matthew; Couch, Warrick J.; Dalton, Gavin B.; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Frenk, Carlos S.; Glazebrook, Karl; Jackson, Carole A.; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve J.; Madgwick, Darren; Norberg, Peder; Peacock, John A.; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2005-10-01

    The ROSAT-European Southern Observatory (ESO) flux-limited X-ray (REFLEX) galaxy cluster survey and the Two-degree Field Galaxy Redshift Survey (2dFGRS), respectively, comprise the largest, homogeneous X-ray selected cluster catalogue and completed galaxy redshift survey. In this work, we combine these two outstanding data sets in order to study the effect of the large-scale cluster environment, as traced by X-ray luminosity, on the properties of the cluster member galaxies. We measure the LX-σr relation from the correlated data set and find it to be consistent with recent results found in the literature. Using a sample of 19 clusters with LX>= 0.36 × 1044 erg s-1 in the 0.1-2.4 keV band, and 49 clusters with lower X-ray luminosity, we find that the fraction of early spectral type (η<=-1.4), passively evolving galaxies is significantly higher in the high-LX sample within R200. We extend the investigation to include composite bJ cluster luminosity functions, and find that the characteristic magnitude of the Schechter-function fit to the early-type luminosity function is fainter for the high-LX sample compared to the low-LX sample (ΔM*= 0.58 +/- 0.14). This seems to be driven by a deficit of such galaxies with MbJ~-21. In contrast, we find no significant differences between the luminosity functions of star-forming, late-type galaxies. We believe these results are consistent with a scenario in which the high-LX clusters are more dynamically evolved systems than the low-LX clusters.

  13. High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images

    SciTech Connect

    Leong, Andrew F. T.; Islam, M. Sirajul; Kitchen, Marcus J.; Fouras, Andreas; Wallace, Megan J.; Hooper, Stuart B.

    2013-04-15

    Purpose: Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. Methods: The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions {approx}16.2 {mu}m). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. Results: Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. Conclusions: This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using

  14. Low-dose 2D X-ray angiography enhancement using 2-axis PCA for the preservation of blood-vessel region and noise minimization.

    PubMed

    Lee, Yong Geun; Lee, Jeongjin; Shin, Yeong-Gil; Kang, Ho Chul

    2016-01-01

    Enhancing 2D angiography while maintaining a low radiation dose has become an important research topic. However, it is difficult to enhance images while preserving vessel-structure details because X-ray noise and contrast blood vessels in 2D angiography have similar intensity distributions, which can lead to ambiguous images of vessel structures. In this paper, we propose a novel and fast vessel-enhancement method for 2D angiography. We apply filtering in the principal component analysis domain for vessel regions and background regions separately, using assumptions based on energy compaction. First, we identify an approximate vessel region using a Hessian-based method. Vessel and non-vessel regions are then represented sparsely by calculating their optimal bases separately. This is achieved by identifying periodic motion in the vessel region caused by the flow of the contrast medium through the blood vessels when viewed on the time axis. Finally, we obtain noise-free images by removing noise in the new coordinate domain for the optimal bases. Our method was validated for an X-ray system, using 10 low-dose sets for training and 20 low-dose sets for testing. The results were compared with those for a high-dose dataset with respect to noise-free images. The average enhancement rate was 93.11±0.71%. The average processing time for enhancing video comprising 50-70 frames was 0.80±0.35s, which is much faster than the previously proposed technique. Our method is applicable to 2D angiography procedures such as catheterization, which requires rapid and natural vessel enhancement.

  15. A Hidden Markov Model for 3D Catheter Tip Tracking with 2D X-ray Catheterization Sequence and 3D Rotational Angiography.

    PubMed

    Ambrosini, Pierre; Smal, Ihor; Ruijters, Daniel; Niessen, Wiro; Moelker, Adriaan; van Walsum, Theo

    2016-11-07

    In minimal invasive image guided catheterization procedures, physicians require information of the catheter position with respect to the patient's vasculature. However, in fluoroscopic images, visualization of the vasculature requires toxic contrast agent. Static vasculature roadmapping, which can reduce the usage of iodine contrast, is hampered by the breathing motion in abdominal catheterization. In this paper, we propose a method to track the catheter tip inside the patient's 3D vessel tree using intra-operative single-plane 2D X-ray image sequences and a peri-operative 3D rotational angiography (3DRA). The method is based on a hidden Markov model (HMM) where states of the model are the possible positions of the catheter tip inside the 3D vessel tree. The transitions from state to state model the probabilities for the catheter tip to move from one position to another. The HMM is updated following the observation scores, based on the registration between the 2D catheter centerline extracted from the 2D X-ray image, and the 2D projection of 3D vessel tree centerline extracted from the 3DRA. The method is extensively evaluated on simulated and clinical datasets acquired during liver abdominal catheterization. The evaluations show a median 3D tip tracking error of 2.3 mm with optimal settings in simulated data. The registered vessels close to the tip have a median distance error of 4.7 mm with angiographic data and optimal settings. Such accuracy is sufficient to help the physicians with an up-to-date roadmapping. The method tracks in real-time the catheter tip and enables roadmapping during catheterization procedures.

  16. Comparison of the bubble size distribution in silicate foams using 2D images and 3D x-ray microtomography

    NASA Astrophysics Data System (ADS)

    Robert, Genevieve; Baker, Don R.; Rivers, Mark L.; Allard, Emilie; Larocque, Jeffery

    2004-10-01

    Three silicate glasses were hydrated at high pressure and then heated at atmospheric pressure to exsolve the water into bubbles and create foams. The bubble size distribution in these foams was measured by x-ray microtomography on the GSECARS BM-13 beamline at the Advanced Photon Source. The bubble area distributions were measured in two dimensions using the image slices produced from the microtomography and the software ImageJ. The bubble volume distributions were measured from the three-dimensional tomographic images with the BLOB3D software. We found that careful analysis of the microtomography data in both two and three dimensions was necessary to avoid the physically unrealistic, experimental artifact of identifying and counting many small bubbles whose surfaces were not defined by a septum of glass. When this artifact was avoided the foams demonstrated power-law distributions of bubble sizes in both two and three dimensions. Conversion of the power-law exponents for bubble areas measured in two dimensions to exponents for bubble volumes usually agreed with the measured three dimensional volume exponents. Furthermore, the power-law distributions for bubble volumes typically agree with multiple theories of bubble growth, all of which yield an exponent of 1 for the cumulative bubble volume distribution. The measured bubble volume distributions with exponents near 0.3 can be explained by diffusive growth as proposed by other authors, but distributions with exponents near 1.4 remain to be explained and are the subject of continuing research on the effects of water concentration and melt viscosity on foaming behavior.

  17. Upper Gastrointestinal (GI) Tract X-Ray (Radiography)

    MedlinePlus

    ... real-time x-ray called fluoroscopy and a barium-based contrast material to produce images of the ... and an orally ingested contrast material such as barium . An x-ray (radiograph) is a noninvasive medical ...

  18. Calcification content quantification by dual-energy x-ray absorptiometry with a 2D digital radiographic detector

    NASA Astrophysics Data System (ADS)

    Dinten, Jean M.; Robert-Coutant, Christine; Darboux, Michel; Gonon, Georges; Bordy, Thomas

    2003-06-01

    In a previous paper (SPIE Medical Imaging 2001), a dual energy method for bone densitometry using a 2D digital radiographic detector has been presented. In this paper, calcium content quantification performance of the approach is precised. The main challenge is to achieve quantification using scatter-corrected dual energy acquisitions. Therefore a scatter estimation approach, based on an expression of scatter as a functional of the primary flux, has been developed. This expression is derived from the Klein and Nishina equation and includes tabulated scatter level values. The calcium quantification performances are validated on two configurations. A first one is issued from criteria developed by the French "Groupe de Recherche et d'Information sur les Osteoporoses." It is based on the use of a phantom made of five 3mm thick PVC sheets in the form of five steps, representing five different bone mineral density values, included in a lucite container filled with water. Additional lucite plates can be put over the phantom. This phantom has been used for evaluation of quantification robustness versus patient thickness and composition variations, and for accuracy evaluation. The second configuration, composed of small calcified objects (representative of lung nodules), is used for evaluating capacities to differentiate calcified from non calcified nodules and to test calcium content quantification performance.

  19. Three-Dimensional Mapping of Soil Chemical Characteristics at Micrometric Scale by Combining 2D SEM-EDX Data and 3D X-Ray CT Images

    PubMed Central

    Hapca, Simona; Baveye, Philippe C.; Wilson, Clare; Lark, Richard Murray; Otten, Wilfred

    2015-01-01

    There is currently a significant need to improve our understanding of the factors that control a number of critical soil processes by integrating physical, chemical and biological measurements on soils at microscopic scales to help produce 3D maps of the related properties. Because of technological limitations, most chemical and biological measurements can be carried out only on exposed soil surfaces or 2-dimensional cuts through soil samples. Methods need to be developed to produce 3D maps of soil properties based on spatial sequences of 2D maps. In this general context, the objective of the research described here was to develop a method to generate 3D maps of soil chemical properties at the microscale by combining 2D SEM-EDX data with 3D X-ray computed tomography images. A statistical approach using the regression tree method and ordinary kriging applied to the residuals was developed and applied to predict the 3D spatial distribution of carbon, silicon, iron, and oxygen at the microscale. The spatial correlation between the X-ray grayscale intensities and the chemical maps made it possible to use a regression-tree model as an initial step to predict the 3D chemical composition. For chemical elements, e.g., iron, that are sparsely distributed in a soil sample, the regression-tree model provides a good prediction, explaining as much as 90% of the variability in some of the data. However, for chemical elements that are more homogenously distributed, such as carbon, silicon, or oxygen, the additional kriging of the regression tree residuals improved significantly the prediction with an increase in the R2 value from 0.221 to 0.324 for carbon, 0.312 to 0.423 for silicon, and 0.218 to 0.374 for oxygen, respectively. The present research develops for the first time an integrated experimental and theoretical framework, which combines geostatistical methods with imaging techniques to unveil the 3-D chemical structure of soil at very fine scales. The methodology presented

  20. Three-Dimensional Mapping of Soil Chemical Characteristics at Micrometric Scale by Combining 2D SEM-EDX Data and 3D X-Ray CT Images.

    PubMed

    Hapca, Simona; Baveye, Philippe C; Wilson, Clare; Lark, Richard Murray; Otten, Wilfred

    2015-01-01

    There is currently a significant need to improve our understanding of the factors that control a number of critical soil processes by integrating physical, chemical and biological measurements on soils at microscopic scales to help produce 3D maps of the related properties. Because of technological limitations, most chemical and biological measurements can be carried out only on exposed soil surfaces or 2-dimensional cuts through soil samples. Methods need to be developed to produce 3D maps of soil properties based on spatial sequences of 2D maps. In this general context, the objective of the research described here was to develop a method to generate 3D maps of soil chemical properties at the microscale by combining 2D SEM-EDX data with 3D X-ray computed tomography images. A statistical approach using the regression tree method and ordinary kriging applied to the residuals was developed and applied to predict the 3D spatial distribution of carbon, silicon, iron, and oxygen at the microscale. The spatial correlation between the X-ray grayscale intensities and the chemical maps made it possible to use a regression-tree model as an initial step to predict the 3D chemical composition. For chemical elements, e.g., iron, that are sparsely distributed in a soil sample, the regression-tree model provides a good prediction, explaining as much as 90% of the variability in some of the data. However, for chemical elements that are more homogenously distributed, such as carbon, silicon, or oxygen, the additional kriging of the regression tree residuals improved significantly the prediction with an increase in the R2 value from 0.221 to 0.324 for carbon, 0.312 to 0.423 for silicon, and 0.218 to 0.374 for oxygen, respectively. The present research develops for the first time an integrated experimental and theoretical framework, which combines geostatistical methods with imaging techniques to unveil the 3-D chemical structure of soil at very fine scales. The methodology presented

  1. An algorithm for kilovoltage x-ray dose calculations with applications in kV-CBCT scans and 2D planar projected radiographs

    NASA Astrophysics Data System (ADS)

    Pawlowski, Jason M.; Ding, George X.

    2014-04-01

    A new model-based dose calculation algorithm is presented for kilovoltage x-rays and is tested for the cases of calculating the radiation dose from kilovoltage cone-beam CT (kV-CBCT) and 2D planar projected radiographs. This algorithm calculates the radiation dose to water-like media as the sum of primary and scattered dose components. The scatter dose is calculated by convolution of a newly introduced, empirically parameterized scatter dose kernel with the primary photon fluence. Several approximations are introduced to increase the scatter dose calculation efficiency: (1) the photon energy spectrum is approximated as monoenergetic; (2) density inhomogeneities are accounted for by implementing a global distance scaling factor in the scatter kernel; (3) kernel tilting is ignored. These approximations allow for efficient calculation of the scatter dose convolution with the fast Fourier transform. Monte Carlo simulations were used to obtain the model parameters. The accuracy of using this model-based algorithm was validated by comparing with the Monte Carlo method for calculating dose distributions for real patients resulting from radiotherapy image guidance procedures including volumetric kV-CBCT scans and 2D planar projected radiographs. For all patients studied, mean dose-to-water errors for kV-CBCT are within 0.3% with a maximum standard deviation error of 4.1%. Using a medium-dependent correction method to account for the effects of photoabsorption in bone on the dose distribution, mean dose-to-medium errors for kV-CBCT are within 3.6% for bone and 2.4% for soft tissues. This algorithm offers acceptable accuracy and has the potential to extend the applicability of model-based dose calculation algorithms from megavoltage to kilovoltage photon beams.

  2. A method of 2D/3D registration of a statistical mouse atlas with a planar X-ray projection and an optical photo

    PubMed Central

    Wang, Hongkai; Stout, David B; Chatziioannou, Arion F

    2013-01-01

    The development of sophisticated and high throughput whole body small animal imaging technologies has created a need for improved image analysis and increased automation. The registration of a digital mouse atlas to individual images is a prerequisite for automated organ segmentation and uptake quantification. This paper presents a fully-automatic method for registering a statistical mouse atlas with individual subjects based on an anterior-posterior X-ray projection and a lateral optical photo of the mouse silhouette. The mouse atlas was trained as a statistical shape model based on 83 organ-segmented micro-CT images. For registration, a hierarchical approach is applied which first registers high contrast organs, and then estimates low contrast organs based on the registered high contrast organs. To register the high contrast organs, a 2D-registration-back-projection strategy is used that deforms the 3D atlas based on the 2D registrations of the atlas projections. For validation, this method was evaluated using 55 subjects of preclinical mouse studies. The results showed that this method can compensate for moderate variations of animal postures and organ anatomy. Two different metrics, the Dice coefficient and the average surface distance, were used to assess the registration accuracy of major organs. The Dice coefficients vary from 0.31±0.16 for the spleen to 0.88±0.03 for the whole body, and the average surface distance varies from 0.54±0.06 mm for the lungs to 0.85±0.10 mm for the skin. The method was compared with a direct 3D deformation optimization (without 2D-registration-back-projection) and a single-subject atlas registration (instead of using the statistical atlas). The comparison revealed that the 2D-registration-back-projection strategy significantly improved the registration accuracy, and the use of the statistical mouse atlas led to more plausible organ shapes than the single-subject atlas. This method was also tested with shoulder xenograft

  3. A volumetric model-based 2D to 3D registration method for measuring kinematics of natural knees with single-plane fluoroscopy

    SciTech Connect

    Tsai, Tsung-Yuan; Lu, Tung-Wu; Chen, Chung-Ming; Kuo, Mei-Ying; Hsu, Horng-Chaung

    2010-03-15

    Purpose: Accurate measurement of the three-dimensional (3D) rigid body and surface kinematics of the natural human knee is essential for many clinical applications. Existing techniques are limited either in their accuracy or lack more realistic experimental evaluation of the measurement errors. The purposes of the study were to develop a volumetric model-based 2D to 3D registration method, called the weighted edge-matching score (WEMS) method, for measuring natural knee kinematics with single-plane fluoroscopy to determine experimentally the measurement errors and to compare its performance with that of pattern intensity (PI) and gradient difference (GD) methods. Methods: The WEMS method gives higher priority to matching of longer edges of the digitally reconstructed radiograph and fluoroscopic images. The measurement errors of the methods were evaluated based on a human cadaveric knee at 11 flexion positions. Results: The accuracy of the WEMS method was determined experimentally to be less than 0.77 mm for the in-plane translations, 3.06 mm for out-of-plane translation, and 1.13 deg. for all rotations, which is better than that of the PI and GD methods. Conclusions: A new volumetric model-based 2D to 3D registration method has been developed for measuring 3D in vivo kinematics of natural knee joints with single-plane fluoroscopy. With the equipment used in the current study, the accuracy of the WEMS method is considered acceptable for the measurement of the 3D kinematics of the natural knee in clinical applications.

  4. Low-dimensional systems investigated by x-ray absorption spectroscopy: a selection of 2D, 1D and 0D cases

    NASA Astrophysics Data System (ADS)

    Mino, Lorenzo; Agostini, Giovanni; Borfecchia, Elisa; Gianolio, Diego; Piovano, Andrea; Gallo, Erik; Lamberti, Carlo

    2013-10-01

    Over the last three decades low-dimensional systems have attracted increasing interest both from the fundamental and technological points of view due to their unique physical and chemical properties. X-ray absorption spectroscopy (XAS) is a powerful tool for the characterization of such kinds of systems, owing to its chemical selectivity and high sensitivity in interatomic distance determination. Moreover, XAS does not require long-range ordering, that is usually absent in low-dimensional systems. Finally, this technique can simultaneously provide information on electronic and local structural properties of the nanomaterials, significantly contributing to clarify the relation between their atomic structure and their peculiar physical properties. This review provides a general introduction to XAS, discussing the basic theory of the technique, the most used detection modes, the related experimental setups and some complementary relevant characterization techniques (diffraction anomalous fine structure, extended energy-loss fine structure, pair distribution function, x-ray emission spectroscopy, high-energy resolution fluorescence detected XAS and x-ray Raman scattering). Subsequently, a selection of significant applications of XAS to two-, one- and zero-dimensional systems will be presented. The selected low-dimensional systems include IV and III-V semiconductor films, quantum wells, quantum wires and quantum dots; carbon-based nanomaterials (epitaxial graphene and carbon nanotubes); metal oxide films, nanowires, nanorods and nanocrystals; metal nanoparticles. Finally, the future perspectives for the application of XAS to nanostructures are discussed.

  5. Three-dimensional mapping of soil chemical characteristics at micrometric scale: Statistical prediction by combining 2D SEM-EDX data and 3D X-ray computed micro-tomographic images

    NASA Astrophysics Data System (ADS)

    Hapca, Simona

    2015-04-01

    Many soil properties and functions emerge from interactions of physical, chemical and biological processes at microscopic scales, which can be understood only by integrating techniques that traditionally are developed within separate disciplines. While recent advances in imaging techniques, such as X-ray computed tomography (X-ray CT), offer the possibility to reconstruct the 3D physical structure at fine resolutions, for the distribution of chemicals in soil, existing methods, based on scanning electron microscope (SEM) and energy dispersive X-ray detection (EDX), allow for characterization of the chemical composition only on 2D surfaces. At present, direct 3D measurement techniques are still lacking, sequential sectioning of soils, followed by 2D mapping of chemical elements and interpolation to 3D, being an alternative which is explored in this study. Specifically, we develop an integrated experimental and theoretical framework which combines 3D X-ray CT imaging technique with 2D SEM-EDX and use spatial statistics methods to map the chemical composition of soil in 3D. The procedure involves three stages 1) scanning a resin impregnated soil cube by X-ray CT, followed by precision cutting to produce parallel thin slices, the surfaces of which are scanned by SEM-EDX, 2) alignment of the 2D chemical maps within the internal 3D structure of the soil cube, and 3) development, of spatial statistics methods to predict the chemical composition of 3D soil based on the observed 2D chemical and 3D physical data. Specifically, three statistical models consisting of a regression tree, a regression tree kriging and cokriging model were used to predict the 3D spatial distribution of carbon, silicon, iron and oxygen in soil, these chemical elements showing a good spatial agreement between the X-ray grayscale intensities and the corresponding 2D SEM-EDX data. Due to the spatial correlation between the physical and chemical data, the regression-tree model showed a great potential

  6. Phase-sensitive X-ray imager

    SciTech Connect

    Baker, Kevin Louis

    2013-01-08

    X-ray phase sensitive wave-front sensor techniques are detailed that are capable of measuring the entire two-dimensional x-ray electric field, both the amplitude and phase, with a single measurement. These Hartmann sensing and 2-D Shear interferometry wave-front sensors do not require a temporally coherent source and are therefore compatible with x-ray tubes and also with laser-produced or x-pinch x-ray sources.

  7. Piecewise-rigid 2D-3D registration for pose estimation of snake-like manipulator using an intraoperative x-ray projection

    NASA Astrophysics Data System (ADS)

    Otake, Y.; Murphy, R. J.; Kutzer, M. D.; Taylor, R. H.; Armand, M.

    2014-03-01

    Background: Snake-like dexterous manipulators may offer significant advantages in minimally-invasive surgery in areas not reachable with conventional tools. Precise control of a wire-driven manipulator is challenging due to factors such as cable deformation, unknown internal (cable friction) and external forces, thus requiring correcting the calibration intraoperatively by determining the actual pose of the manipulator. Method: A method for simultaneously estimating pose and kinematic configuration of a piecewise-rigid object such as a snake-like manipulator from a single x-ray projection is presented. The method parameterizes kinematics using a small number of variables (e.g., 5), and optimizes them simultaneously with the 6 degree-of-freedom pose parameter of the base link using an image similarity between digitally reconstructed radiographs (DRRs) of the manipulator's attenuation model and the real x-ray projection. Result: Simulation studies assumed various geometric magnifications (1.2-2.6) and out-of-plane angulations (0°-90°) in a scenario of hip osteolysis treatment, which demonstrated the median joint angle error was 0.04° (for 2.0 magnification, +/-10° out-of-plane rotation). Average computation time was 57.6 sec with 82,953 function evaluations on a mid-range GPU. The joint angle error remained lower than 0.07° while out-of-plane rotation was 0°-60°. An experiment using video images of a real manipulator demonstrated a similar trend as the simulation study except for slightly larger error around the tip attributed to accumulation of errors induced by deformation around each joint not modeled with a simple pin joint. Conclusions: The proposed approach enables high precision tracking of a piecewise-rigid object (i.e., a series of connected rigid structures) using a single projection image by incorporating prior knowledge about the shape and kinematic behavior of the object (e.g., each rigid structure connected by a pin joint parameterized by a

  8. Synchrotron X-ray 2D and 3D Elemental Imaging of CdSe/ZnS Quantum dot Nanoparticles in Daphnia Magna

    SciTech Connect

    Jackson, B.; Pace, H; Lanzirotti, A; Smith, R; Ranville, J

    2009-01-01

    The potential toxicity of nanoparticles to aquatic organisms is of interest given that increased commercialization will inevitably lead to some instances of inadvertent environmental exposures. Cadmium selenide quantum dots (QDs) capped with zinc sulfide are used in the semiconductor industry and in cellular imaging. Their small size (<10 nm) suggests that they may be readily assimilated by exposed organisms. We exposed Daphnia magna to both red and green QDs and used synchrotron X-ray fluorescence to study the distribution of Zn and Se in the organism over a time period of 36 h. The QDs appeared to be confined to the gut, and there was no evidence of further assimilation into the organism. Zinc and Se fluorescence signals were highly correlated, suggesting that the QDs had not dissolved to any extent. There was no apparent difference between red or green QDs, i.e., there was no effect of QD size. 3D tomography confirmed that the QDs were exclusively in the gut area of the organism. It is possible that the QDs aggregated and were therefore too large to cross the gut wall.

  9. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  10. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  11. Chest X-Ray

    MedlinePlus

    ... by Image/Video Gallery Your radiologist explains chest x-ray. Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  12. Joint x-ray

    MedlinePlus

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  13. HipMatch: an object-oriented cross-platform program for accurate determination of cup orientation using 2D-3D registration of single standard X-ray radiograph and a CT volume.

    PubMed

    Zheng, Guoyan; Zhang, Xuan; Steppacher, Simon D; Murphy, Stephen B; Siebenrock, Klaus A; Tannast, Moritz

    2009-09-01

    The widely used procedure of evaluation of cup orientation following total hip arthroplasty using single standard anteroposterior (AP) radiograph is known inaccurate, largely due to the wide variability in individual pelvic orientation relative to X-ray plate. 2D-3D image registration methods have been introduced for an accurate determination of the post-operative cup alignment with respect to an anatomical reference extracted from the CT data. Although encouraging results have been reported, their extensive usage in clinical routine is still limited. This may be explained by their requirement of a CAD model of the prosthesis, which is often difficult to be organized from the manufacturer due to the proprietary issue, and by their requirement of either multiple radiographs or a radiograph-specific calibration, both of which are not available for most retrospective studies. To address these issues, we developed and validated an object-oriented cross-platform program called "HipMatch" where a hybrid 2D-3D registration scheme combining an iterative landmark-to-ray registration with a 2D-3D intensity-based registration was implemented to estimate a rigid transformation between a pre-operative CT volume and the post-operative X-ray radiograph for a precise estimation of cup alignment. No CAD model of the prosthesis is required. Quantitative and qualitative results evaluated on cadaveric and clinical datasets are given, which indicate the robustness and the accuracy of the program. HipMatch is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway), VTK, and Coin3D and is transportable to any platform.

  14. 2D-NMR, X-ray crystallography and theoretical studies of the reaction mechanism for the synthesis of 1,5-benzodiazepines from dehydroacetic acid derivatives and o-phenylenediamines

    NASA Astrophysics Data System (ADS)

    Rabahi, Amal; Hamdi, Safouane M.; Rachedi, Yahia; Hamdi, Maamar; Talhi, Oualid; Almeida Paz, Filipe A.; Silva, Artur S. M.; Fadila, Balegroune; Malika, Hamadène; Kamel, Taïbi

    2014-03-01

    The synthesis of 1,5-benzodiazepines by the reaction of o-phenylenediamines (o-PDAs) with dehydroacetic acid DHAA [3-acetyl-4-hydroxy-6-methyl-2H-pyran-2-one] or conjugate analogues is largely reported in the literature, but still with uncontrolled stereochemistry. In this work, a comprehensive mechanistic study on the formation of some synthesized 1,5-benzodiazepine models following different organic routes is established based on liquid-state 2D NMR, single-crystal X-ray diffraction and theoretical calculations allowing the classification of two prototropic forms A (enaminopyran-2,4-dione) and B (imino-4-hydroxypyran-2-one). Evidences are presented to show that most of the reported 1,5-benzodiazepine structures arising from DHAA and derivatives preferentially adopt the (E)-enaminopyran-2,4-diones A.

  15. Robust automatic rigid registration of MRI and X-ray using external fiducial markers for XFM-guided interventional procedures

    PubMed Central

    George, Ashvin K.; Sonmez, Merdim; Lederman, Robert J.; Faranesh, Anthony Z.

    2011-01-01

    Purpose: In X-ray fused with MRI, previously gathered roadmap MRI volume images are overlaid on live X-ray fluoroscopy images to help guide the clinician during an interventional procedure. The incorporation of MRI data allows for the visualization of soft tissue that is poorly visualized under X-ray. The widespread clinical use of this technique will require fully automating as many components as possible. While previous use of this method has required time-consuming manual intervention to register the two modalities, in this article, the authors present a fully automatic rigid-body registration method. Methods: External fiducial markers that are visible under these two complimentary imaging modalities were used to register the X-ray images with the roadmap MR images. The method has three components: (a) The identification of the 3D locations of the markers from a full 3D MR volume, (b) the identification of the 3D locations of the markers from a small number of 2D X-ray fluoroscopy images, and (c) finding the rigid-body transformation that registers the two point sets in the two modalities. For part (a), the localization of the markers from MR data, the MR volume image was thresholded, connected voxels were segmented and labeled, and the centroids of the connected components were computed. For part (b), the X-ray projection images, produced by an image intensifier, were first corrected for distortions. Binary mask images of the markers were created from the distortion-corrected X-ray projection images by applying edge detection, pattern recognition, and image morphological operations. The markers were localized in the X-ray frame using an iterative backprojection-based method which segments voxels in the volume of interest, discards false positives based on the previously computed edge-detected projections, and calculates the locations of the true markers as the centroids of the clusters of voxels that remain. For part (c), a variant of the iterative closest

  16. Robust automatic rigid registration of MRI and X-ray using external fiducial markers for XFM-guided interventional procedures

    SciTech Connect

    George, Ashvin K.; Sonmez, Merdim; Lederman, Robert J.; Faranesh, Anthony Z.

    2011-01-15

    Purpose: In X-ray fused with MRI, previously gathered roadmap MRI volume images are overlaid on live X-ray fluoroscopy images to help guide the clinician during an interventional procedure. The incorporation of MRI data allows for the visualization of soft tissue that is poorly visualized under X-ray. The widespread clinical use of this technique will require fully automating as many components as possible. While previous use of this method has required time-consuming manual intervention to register the two modalities, in this article, the authors present a fully automatic rigid-body registration method. Methods: External fiducial markers that are visible under these two complimentary imaging modalities were used to register the X-ray images with the roadmap MR images. The method has three components: (a) The identification of the 3D locations of the markers from a full 3D MR volume, (b) the identification of the 3D locations of the markers from a small number of 2D X-ray fluoroscopy images, and (c) finding the rigid-body transformation that registers the two point sets in the two modalities. For part (a), the localization of the markers from MR data, the MR volume image was thresholded, connected voxels were segmented and labeled, and the centroids of the connected components were computed. For part (b), the X-ray projection images, produced by an image intensifier, were first corrected for distortions. Binary mask images of the markers were created from the distortion-corrected X-ray projection images by applying edge detection, pattern recognition, and image morphological operations. The markers were localized in the X-ray frame using an iterative backprojection-based method which segments voxels in the volume of interest, discards false positives based on the previously computed edge-detected projections, and calculates the locations of the true markers as the centroids of the clusters of voxels that remain. For part (c), a variant of the iterative closest

  17. Automated 3D-2D registration of X-ray microcomputed tomography with histological sections for dental implants in bone using chamfer matching and simulated annealing.

    PubMed

    Becker, Kathrin; Stauber, Martin; Schwarz, Frank; Beißbarth, Tim

    2015-09-01

    We propose a novel 3D-2D registration approach for micro-computed tomography (μCT) and histology (HI), constructed for dental implant biopsies, that finds the position and normal vector of the oblique slice from μCT that corresponds to HI. During image pre-processing, the implants and the bone tissue are segmented using a combination of thresholding, morphological filters and component labeling. After this, chamfer matching is employed to register the implant edges and fine registration of the bone tissues is achieved using simulated annealing. The method was tested on n=10 biopsies, obtained at 20 weeks after non-submerged healing in the canine mandible. The specimens were scanned with μCT 100 and processed for hard tissue sectioning. After registration, we assessed the agreement of bone to implant contact (BIC) using automated and manual measurements. Statistical analysis was conducted to test the agreement of the BIC measurements in the registered samples. Registration was successful for all specimens and agreement of the respective binary images was high (median: 0.90, 1.-3. Qu.: 0.89-0.91). Direct comparison of BIC yielded that automated (median 0.82, 1.-3. Qu.: 0.75-0.85) and manual (median 0.61, 1.-3. Qu.: 0.52-0.67) measures from μCT were significant positively correlated with HI (median 0.65, 1.-3. Qu.: 0.59-0.72) between μCT and HI groups (manual: R(2)=0.87, automated: R(2)=0.75, p<0.001). The results show that this method yields promising results and that μCT may become a valid alternative to assess osseointegration in three dimensions.

  18. Three-dimensional textural analysis of products from the Vulcanian explosions of Soufrière Hills Volcano, Montserrat, 1997, using X-ray computed microtomography: comparison with 2D data and implications for vesiculation processes

    NASA Astrophysics Data System (ADS)

    Giachetti, T.; Burgisser, A.; Druitt, T. H.

    2009-12-01

    X-ray computed microtomography is a powerful, non-destructive method for imaging textures and for quantifying vesicle spatial relationships and size distributions. It was applied to one breadcrust bomb and three pumices from the 1997 Vulcanian explosions of the Soufrière Hills Volcano, Montserrat. A detailed 2D textural study of these same samples, including high-resolution vesicle size distributions, has already been carried out. In order to cover the wide range of vesicle and crystal sizes (few µm to a few hundreds of µm), we acquired tomographic images at three magnifications (0.37, 4.0 and 17.4 µm/voxel) on each sample. Each magnification covers only part of the whole vesicle size range, but with large overlaps. Vesicle walls were reconstructed using ImageJ and 3DMA_Rock softwares, and a Matlab code was written to combine the data from the three stacks and to calculate vesicle size and sphericity distributions for the whole sample. Comparison with the 2D results show only minor differences in the vesicle size distributions. Cumulative vesicle number densities obtained by the two methods are of the same order of magnitude (~1015 m-3 of glass). Three vesicle populations are recognized in the samples, the same three recognized in 2D, although minor shifts in modes are observed. As in 2D, vesicle sphericity decreases with size, vesicle shape being progressively more complicated as the vesicle grows and coalesces with neighbours. Coalescence in all samples appears to occur between neighbouring vesicles of any sizes, but, as intuitively expected, the larger the vesicle, the more connected it is. Our results show that coalescence affected indifferently pre- and syn-eruptive bubbles. This suggests that the syn-eruptive gas was rapidly connected to large-scale pathways through which it could escape. Depending on clast permeability, this mechanism has the potential to double the amount of gas available for propulsion of the Vulcanian jet.

  19. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  20. X-ray (image)

    MedlinePlus

    X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

  1. Bone x-ray

    MedlinePlus

    ... not being scanned. Alternative Names X-ray - bone Images Skeleton Skeletal spine Osteogenic sarcoma - x-ray References ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  2. X-ray

    MedlinePlus

    ... think you might be pregnant. Alternative Names Radiography Images X-ray X-ray References Geleijns J, Tack ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  3. Extremity x-ray

    MedlinePlus

    ... sensitive to the risks of an x-ray. Images X-ray References Kelly DM. Congenital anomalies of ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  4. X-Ray Toolkit

    SciTech Connect

    2015-10-20

    Radiographic Image Acquisition & Processing Software for Security Markets. Used in operation of commercial x-ray scanners and manipulation of x-ray images for emergency responders including State, Local, Federal, and US Military bomb technicians and analysts.

  5. Sinus x-ray

    MedlinePlus

    Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Brown J, Rout J. ENT, neck, and dental radiology. In: Adam A, Dixon AK, Gillard JH Schaefer- ...

  6. Hand x-ray

    MedlinePlus

    X-ray - hand ... A hand x-ray is taken in a hospital radiology department or your health care provider's office by an ... technician. You will be asked to place your hand on the x-ray table, and keep it ...

  7. X-ray and magnetic resonance imaging fusion for cardiac resynchronization therapy.

    PubMed

    Choi, Jinwoo; Radau, Perry; Xu, Robert; Wright, Graham A

    2016-07-01

    Cardiac Resynchronization Therapy (CRT) can effectively treat left ventricle (LV) driven Heart Failure (HF). However, 30% of the CRT recipients do not experience symptomatic benefit. Recent studies show that the CRT response rate can reach 95% when the LV pacing lead is placed at an optimal site at a region of maximal LV dyssynchrony and away from myocardial scars. Cardiac Magnetic Resonance (CMR) can identify the optimal site in three dimensions (3D). 3D CMR data can be registered to clinical standard x-ray fluoroscopy to achieve an optimal pacing of the LV. We have developed a 3D CMR to 2D x-ray image registration method for CRT procedures. We have employed the LV pacing lead on x-ray images and coronary sinus on MR data as landmarks. The registration method makes use of a guidewire simulation algorithm, edge based image registration technique and x-ray C-arm tracking to register the coronary sinus and pacing lead landmarks.

  8. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  9. X-Ray

    MedlinePlus

    ... of gray. For some types of X-ray tests, a contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the images. X-ray technology is used to examine many parts of the ...

  10. Chest X-Ray

    MedlinePlus Videos and Cool Tools

    ... Site Index A-Z Spotlight Recently posted: Anal Cancer Facet Joint Block Video: Lung Cancer Screening Video: Upper GI Tract X-ray Video: ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  11. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  12. X-ray beamsplitter

    DOEpatents

    Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

    1989-01-01

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

  13. Dental x-rays

    MedlinePlus

    ... X-rays are a form of high energy electromagnetic radiation. The x-rays penetrate the body to form ... for detecting cavities, unless the decay is very advanced and deep. Many ... The amount of radiation given off during the procedure is less than ...

  14. X-ray beamsplitter

    DOEpatents

    Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

    1987-08-07

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

  15. X-ray generator

    DOEpatents

    Dawson, John M.

    1976-01-01

    Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

  16. Three-dimensional kinematic estimation of mobile-bearing total knee arthroplasty from x-ray fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Yamazaki, Takaharu; Futai, Kazuma; Tomita, Tetsuya; Sato, Yoshinobu; Yoshikawa, Hideki; Tamura, Shinichi; Sugamoto, Kazuomi

    2011-03-01

    To achieve 3D kinematic analysis of total knee arthroplasty (TKA), 2D/3D registration techniques, which use X-ray fluoroscopic images and computer-aided design (CAD) model of the knee implant, have attracted attention in recent years. These techniques could provide information regarding the movement of radiopaque femoral and tibial components but could not provide information of radiolucent polyethylene insert, because the insert silhouette on X-ray image did not appear clearly. Therefore, it was difficult to obtain 3D kinemaitcs of polyethylene insert, particularly mobile-bearing insert that move on the tibial component. This study presents a technique and the accuracy for 3D kinematic analysis of mobile-bearing insert in TKA using X-ray fluoroscopy, and finally performs clinical applications. For a 3D pose estimation technique of the mobile-bearing insert in TKA using X-ray fluoroscopy, tantalum beads and CAD model with its beads are utilized, and the 3D pose of the insert model is estimated using a feature-based 2D/3D registration technique. In order to validate the accuracy of the present technique, experiments including computer simulation test were performed. The results showed the pose estimation accuracy was sufficient for analyzing mobile-bearing TKA kinematics (the RMS error: about 1.0 mm, 1.0 degree). In the clinical applications, seven patients with mobile-bearing TKA in deep knee bending motion were studied and analyzed. Consequently, present technique enables us to better understand mobile-bearing TKA kinematics, and this type of evaluation was thought to be helpful for improving implant design and optimizing TKA surgical techniques.

  17. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  18. X-ray laser

    DOEpatents

    Nilsen, Joseph

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  19. X-ray superbubbles

    NASA Technical Reports Server (NTRS)

    Cash, W.

    1983-01-01

    Four regions of the galaxy, the Cygnus Superbubble, the Eta Carina complex, the Orion/Eridanus complex, and the Gum Nebula, are discussed as examples of collective effects in the interstellar medium. All four regions share certain features, indicating a common structure. The selection effects which determine the observable X-ray properties of the superbubbles are discussed, and it is demonstrated that only a very few more in our Galaxy can be detected in X rays. X-ray observation of extragalactic superbubbles is shown to be possible but requires the capabilities of a large, high quality, AXAF class observatory.

  20. Synthesis, X-ray crystal structure, optical properties and DFT studies of a new 2D layered iodide bridged Pb(II) coordination polymer with 2,3-bis(2-pyridyl)pyrazine

    SciTech Connect

    Saghatforoush, Lotfali Bakhtiari, Akbar; Gheleji, Hojjat

    2015-01-15

    The synthesis of two dimensional (2D) coordination polymer [Pb{sub 2}(µ-I){sub 2}(µ-dpp-N,N,N,N)(µ-dpp-N,N)I{sub 2}]{sub n} (dpp=2,3-bis(2-pyridyl)pyrazine) is reported. As determined by X-ray diffraction of a twinned crystal, the dpp ligand simultaneously adopts a bis–bidentate and bis–monodentate coordination mode in the crystal structure of compound. The electronic band structure along with density of states (DOS) calculated by the DFT method indicates that the compound is an indirect band gap semiconductor. According to the DFT calculations, the observed emission of the compound at 600 nm in solid phase could be attributed to arise from an excited LLCT state (dpp-π{sup ⁎} [C-2p and N-2p states, CBs] to I-6p state [VBs]). The linear optical properties of the compound are also calculated by DFT method. The structure of the compound in solution phase is discussed based on the measured {sup 1}H NMR and fluorescence spectra in DMSO. TGA studies indicate that the compound is thermally stable up to 210 °C. - Graphical abstract: The synthesis, crystal structure and emission spectra of [Pb{sub 2}(µ-I){sub 2}(µ-dpp-N,N,N,N)(µ-dpp-N,N)I{sub 2}]{sub n} is presented. The electronic band structure and linear optical properties of the compound are calculated by the DFT method. - Highlights: • Two dimensional [Pb{sub 2}(µ-I){sub 2}(µ-dpp-N,N,N,N)(µ-dpp-N,N)I{sub 2}]{sub n} has been prepared. • The structure of the compound is determined by XRD of a twinned crystal. • DFT calculations indicate that the compound is an indirect band gap semiconductor. • As shown by DFT calculations, the emission band of the compound is LLCT. • Solution phase structure of compound is explored by {sup 1}H NMR and emission spectra.

  1. Lumbosacral spine x-ray

    MedlinePlus

    X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray table ...

  2. Thoracic spine x-ray

    MedlinePlus

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... The test is done in a hospital radiology department or in the health care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

  3. X-ray - skeleton

    MedlinePlus

    ... medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this page, ... ray views may be uncomfortable. If the whole skeleton is being imaged, the test usually takes 1 ...

  4. Fluoroscopic x-ray imaging with amorphous silicon thin-film arrays

    NASA Astrophysics Data System (ADS)

    Schiebel, Ulrich W.; Conrads, Norbert; Jung, Norbert; Weibrecht, Martin; Wieczorek, Herfried K.; Zaengel, Thomas T.; Powell, M. J.; French, I. D.; Glasse, C.

    1994-05-01

    The dream of an all-solid state large area x-ray image sensor with digital readout and full dynamic performance will most probably find a first realization in 2D thin-film amorphous silicon arrays. In this paper we address in particular the evaluation of the limits of the signal/noise ratio in this concept. Using small prototype detectors measurements of MTF and noise power spectra have been made as a function of x-ray dose. The results are given in terms of the detective quantum efficiency as a function of dose and spatial frequency. We further present an analysis of the different noise sources and their dependence on the detector parameters, and we provide estimates on the maximum signals that may be achieved per unit dose. The intrinsic lag of the amorphous silicon photodiodes causes a second problem area with this type of x-ray detectors. Especially in radiography/fluoroscopy mixed applications, memory effects may not be negligible.

  5. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1992-01-01

    This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

  6. X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; van den Heuvel, Edward Peter Jacobus

    1997-01-01

    Preface; 1. The properties of X-ray binaries, N. E. White, F. Nagase and A. N. Parmar; 2. Optical and ultraviolet observations of X-ray binaries J. van Paradijs and J. E. McClintock; 3. Black-hole binaries Y. Tanaka and W. H. G. Lewin; 4. X-ray bursts Walter H. G. Lewin, Jan Van Paradijs and Ronald E. Taam; 5. Millisecond pulsars D. Bhattacharya; 6. Rapid aperiodic variability in binaries M. van der Klis; 7. Radio properties of X-ray binaries R. M. Hjellming and X. Han; 8. Cataclysmic variable stars France Anne-Dominic Córdova; 9. Normal galaxies and their X-ray binary populations G. Fabbiano; 10. Accretion in close binaries Andrew King; 11. Formation and evolution of neutron stars and black holes in binaries F. Verbunt and E. P. J. van den Heuvel; 12. The magnetic fields of neutron stars and their evolution D. Bhattacharya and G. Srinivasan; 13. Cosmic gamma-ray bursts K. Hurley; 14. A catalogue of X-ray binaries Jan van Paradijs; 15. A compilation of cataclysmic binaries with known or suspected orbital periods Hans Ritter and Ulrich Kolb; References; Index.

  7. Robust patella motion tracking using intensity-based 2D-3D registration on dynamic bi-plane fluoroscopy: towards quantitative assessment in MPFL reconstruction surgery

    NASA Astrophysics Data System (ADS)

    Otake, Yoshito; Esnault, Matthieu; Grupp, Robert; Kosugi, Shinichi; Sato, Yoshinobu

    2016-03-01

    The determination of in vivo motion of multiple-bones using dynamic fluoroscopic images and computed tomography (CT) is useful for post-operative assessment of orthopaedic surgeries such as medial patellofemoral ligament reconstruction. We propose a robust method to measure the 3D motion of multiple rigid objects with high accuracy using a series of bi-plane fluoroscopic images and a multi-resolution, intensity-based, 2D-3D registration. A Covariance Matrix Adaptation Evolution Strategy (CMA-ES) optimizer was used with a gradient correlation similarity metric. Four approaches to register three rigid objects (femur, tibia-fibula and patella) were implemented: 1) an individual bone approach registering one bone at a time, each with optimization of a six degrees of freedom (6DOF) parameter, 2) a sequential approach registering one bone at a time but using the previous bone results as the background in DRR generation, 3) a simultaneous approach registering all the bones together (18DOF) and 4) a combination of the sequential and the simultaneous approaches. These approaches were compared in experiments using simulated images generated from the CT of a healthy volunteer and measured fluoroscopic images. Over the 120 simulated frames of motion, the simultaneous approach showed improved registration accuracy compared to the individual approach: with less than 0.68mm root-mean-square error (RMSE) for translation and less than 1.12° RMSE for rotation. A robustness evaluation was conducted with 45 trials of a randomly perturbed initialization showed that the sequential approach improved robustness significantly (74% success rate) compared to the individual bone approach (34% success) for patella registration (femur and tibia-fibula registration had a 100% success rate with each approach).

  8. Clocking femtosecond X rays.

    PubMed

    Cavalieri, A L; Fritz, D M; Lee, S H; Bucksbaum, P H; Reis, D A; Rudati, J; Mills, D M; Fuoss, P H; Stephenson, G B; Kao, C C; Siddons, D P; Lowney, D P; Macphee, A G; Weinstein, D; Falcone, R W; Pahl, R; Als-Nielsen, J; Blome, C; Düsterer, S; Ischebeck, R; Schlarb, H; Schulte-Schrepping, H; Tschentscher, Th; Schneider, J; Hignette, O; Sette, F; Sokolowski-Tinten, K; Chapman, H N; Lee, R W; Hansen, T N; Synnergren, O; Larsson, J; Techert, S; Sheppard, J; Wark, J S; Bergh, M; Caleman, C; Huldt, G; van der Spoel, D; Timneanu, N; Hajdu, J; Akre, R A; Bong, E; Emma, P; Krejcik, P; Arthur, J; Brennan, S; Gaffney, K J; Lindenberg, A M; Luening, K; Hastings, J B

    2005-03-25

    Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.

  9. Examination frequency and population dose from medical X-ray examinations in Sudan in 2010.

    PubMed

    Suliman, I I; Ibraheem, S B; Youssif, B E; Abdelgabar, M I; Gafar, R; Elshiekh, E; Ahmed, Nada A; Sulieman, A

    2015-07-01

    This study was performed to estimate examination frequency and collective and per caput effective doses arising from medical X-ray procedures in Sudan, 2010. Information was collected from 30 hospitals performing radiography, computed tomography (CT), fluoroscopy and interventional radiology (IR) procedures. The estimated annual number of examinations was 33 million radiographic X-ray procedures (99 %), 0.34 million CT exams per year (14 % paediatrics CT), 0.02 million fluoroscopy and IR procedures. The estimated annual number of examinations was 326 per 1000 people. The estimated annual collective and per caput effective doses from medical X-ray procedures mount 7197 man Sv and 0.18 mSv, respectively. The study offered the first projection of frequency and population dose from medical X-ray examinations in Sudan and provides estimates of the impact of the medical X-ray procedures at the national level.

  10. 4D rotational x-ray imaging of wrist joint dynamic motion

    SciTech Connect

    Carelsen, Bart; Bakker, Niels H.; Strackee, Simon D.; Boon, Sjirk N.; Maas, Mario; Sabczynski, Joerg; Grimbergen, Cornelis A.; Streekstra, Geert J.

    2005-09-15

    Current methods for imaging joint motion are limited to either two-dimensional (2D) video fluoroscopy, or to animated motions from a series of static three-dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x-ray modalities and sophisticated 2D to 3D matching for the complex wrist joint. We present a method for the acquisition of dynamic 3D images of a moving joint. In our method a 3D-rotational x-ray (3D-RX) system is used to image a cyclically moving joint. The cyclic motion is synchronized to the x-ray acquisition to yield multiple sets of projection images, which are reconstructed to a series of time resolved 3D images, i.e., four-dimensional rotational x ray (4D-RX). To investigate the obtained image quality parameters the full width at half maximum (FWHM) of the point spread function (PSF) via the edge spread function and the contrast to noise ratio between air and phantom were determined on reconstructions of a bullet and rod phantom, using 4D-RX as well as stationary 3D-RX images. The CNR in volume reconstructions based on 251 projection images in the static situation and on 41 and 34 projection images of a moving phantom were 6.9, 3.0, and 2.9, respectively. The average FWHM of the PSF of these same images was, respectively, 1.1, 1.7, and 2.2 mm orthogonal to the motion and parallel to direction of motion 0.6, 0.7, and 1.0 mm. The main deterioration of 4D-RX images compared to 3D-RX images is due to the low number of projection images used and not to the motion of the object. Using 41 projection images seems the best setting for the current system. Experiments on a postmortem wrist show the feasibility of the method for imaging 3D dynamic joint motion. We expect that 4D-RX will pave the way to improved assessment of joint disorders by detection of 3D dynamic motion patterns in joints.

  11. X-ray fluorescence experiment

    NASA Technical Reports Server (NTRS)

    Adler, I.; Trombka, J. I.; Gerard, J.; Schmadebeck, R.; Lowman, P.; Blodgett, H.; Yin, L.; Eller, E.; Lamothe, R.; Gorenstein, P.

    1972-01-01

    The preliminary results from the Sco X-1 and Cyg X-1 obtained from the Apollo 15 X-ray detector data are presented along with preliminary results of the X-ray fluorescence spectrometric data of the lunar surface composition. The production of the characteristic X-rays following the interaction of solar X-rays with the lunar surface is described along with the X-ray spectrometer. Preliminary analyses of the astronomical X-ray observation and the X-ray fluorescence data are presented.

  12. X-ray beam finder

    DOEpatents

    Gilbert, H.W.

    1983-06-16

    An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

  13. Neck x-ray

    MedlinePlus

    ... look at cervical vertebrae. These are the 7 bones of the spine in the neck. ... A neck x-ray can detect: Bone joint that is out of position (dislocation) Breathing in a foreign object Broken bone (fracture) Disk problems (disks ...

  14. Abdominal x-ray

    MedlinePlus

    ... a kidney stone Identify blockage in the intestine Locate an object that has been swallowed Help diagnose diseases, such as tumors or other conditions Normal Results The x-ray will show normal structures for a person your age. What Abnormal Results Mean Abnormal findings ...

  15. Obtaining flat x-ray images from round objects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A technique to correct deficiencies in x-ray images of cylindrical or spherical objects that are a consequence of the geometry of the sample is derived, for both two-dimensional (2D) and linescan imaging. The methods described involve the use of attenuators specifically shaped to equalize the x-ray ...

  16. Two dimensional x-ray phase imaging using single grating interferometer with embedded x-ray targets.

    PubMed

    Morimoto, Naoki; Fujino, Sho; Yamazaki, Amane; Ito, Yasuhiro; Hosoi, Takuji; Watanabe, Heiji; Shimura, Takayoshi

    2015-06-29

    Using multidot metal targets embedded in a diamond substrate, we created a single-grating Talbot-Lau interferometer and used it to capture two dimensional (2D) x-ray phase images. The ensemble of these targets constitutes a tiny virtual array of x-ray source and enables x-ray phase-contrast imaging with no source or absorption grating within a 1 m source-detector distance for 8 keV x-rays. We directly resolved a dot-pattern self-image of the phase grating with 6 µm pitch by using an x-ray image detector with 24 µm pixels and obtained 2D differential-phase and dark-field images from a single-exposure. Using the 2D differential-phase images, we also obtained a phase image with no streak artifacts.

  17. X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    Dr. S. N. Zhang has lead a seven member group (Dr. Yuxin Feng, Mr. XuejunSun, Mr. Yongzhong Chen, Mr. Jun Lin, Mr. Yangsen Yao, and Ms. Xiaoling Zhang). This group has carried out the following activities: continued data analysis from space astrophysical missions CGRO, RXTE, ASCA and Chandra. Significant scientific results have been produced as results of their work. They discovered the three-layered accretion disk structure around black holes in X-ray binaries; their paper on this discovery is to appear in the prestigious Science magazine. They have also developed a new method for energy spectral analysis of black hole X-ray binaries; four papers on this topics were presented at the most recent Atlanta AAS meeting. They have also carried Monte-Carlo simulations of X-ray detectors, in support to the hardware development efforts at Marshall Space Flight Center (MSFC). These computation-intensive simulations have been carried out entirely on the computers at UAH. They have also carried out extensive simulations for astrophysical applications, taking advantage of the Monte-Carlo simulation codes developed previously at MSFC and further improved at UAH for detector simulations. One refereed paper and one contribution to conference proceedings have been resulted from this effort.

  18. X-Ray Vision

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Elsner, R. F.; Engelhaupt, D.; Kolodziejczak, J. J.; ODell, S. L.; Speegle, C. O.; Weisskopf, M. C.

    2004-01-01

    We are fabricating optics for the hard-x-ray region using electroless nickel replication. The attraction of this process, which has been widely used elsewhere, is that the resulting full shell optics are inherently stable and thus can have very good angular resolution. The challenge with this process is to develop lightweight optics (nickel has a relatively high density of 8.9 g/cu cm), and to keep down the costs of mandrel fabrication. We accomplished the former through the development of high-strength nickel alloys that permit very thin shells without fabrication- and handling-induced deformations. For the latter, we have utilized inexpensive grinding and diamond turning to figure the mandrels and then purpose-built polishing machines to finish the surface. In-house plating tanks and a simple water-bath separation system complete the process. To date we have built shells ranging in size from 5 cm diameter to 50 cm, and with thickness down to 100 micron. For our HERO balloon program, we are fabricating over 200 iridium-coated shells, 250 microns thick, for hard-x-ray imaging up to 75 keV. Early test results on these have indicated half-power-diameters of 15 arcsec. The status of these and other hard-x-ray optics will be reviewed.

  19. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  20. X-ray lithography masking

    NASA Technical Reports Server (NTRS)

    Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

    1998-01-01

    X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

  1. Panoramic Dental X-Ray

    MedlinePlus

    ... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a ... Your e-mail address: Personal message (optional): Bees: Wax: Notice: RadiologyInfo respects your privacy. Information entered here ...

  2. Fluctuation X-Ray Scattering

    SciTech Connect

    Saldin, PI: D. K.; Co-I's: J. C. H. Spence and P. Fromme

    2013-01-25

    The work supported by the grant was aimed at developing novel methods of finding the structures of biomolecules using x-rays from novel sources such as the x-ray free electron laser and modern synchrotrons

  3. Abdomen X-Ray (Radiography)

    MedlinePlus

    ... examined, an x-ray machine produces a small burst of radiation that passes through the body, recording ... tissue shows up in shades of gray and air appears black. Until recently, x-ray images were ...

  4. Dual X-ray absorptiometry

    NASA Astrophysics Data System (ADS)

    Altman, Albert; Aaron, Ronald

    2012-07-01

    Dual X-ray absorptiometry is widely used in analyzing body composition and imaging. Both the method and its limitations are related to the Compton and photoelectric contributions to the X-ray attenuation coefficients of materials.

  5. Encapsulating X-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Conley, Joseph M.; Bradley, James G.

    1987-01-01

    Vapor-deposited polymer shields crystals from environment while allowing X rays to pass. Polymer coating transparental to X rays applied to mercuric iodide detector in partial vacuum. Coating protects crystal from sublimation, chemical attack, and electrical degradation.

  6. Coding Strategies for X-ray Tomography

    NASA Astrophysics Data System (ADS)

    Holmgren, Andrew

    This work focuses on the construction and application of coded apertures to compressive X-ray tomography. Coded apertures can be made in a number of ways, each method having an impact on system background and signal contrast. Methods of constructing coded apertures for structuring X-ray illumination and scatter are compared and analyzed. Apertures can create structured X-ray bundles that investigate specific sets of object voxels. The tailored bundles of rays form a code (or pattern) and are later estimated through computational inversion. Structured illumination can be used to subsample object voxels and make inversion feasible for low dose computed tomography (CT) systems, or it can be used to reduce background in limited angle CT systems. On the detection side, coded apertures modulate X-ray scatter signals to determine the position and radiance of scatter points. By forming object dependent projections in measurement space, coded apertures multiplex modulated scatter signals onto a detector. The multiplexed signals can be inverted with knowledge of the code pattern and system geometry. This work shows two systems capable of determining object position and type in a 2D plane, by illuminating objects with an X-ray `fan beam,' using coded apertures and compressive measurements. Scatter tomography can help identify materials in security and medicine that may be ambiguous with transmission tomography alone.

  7. [Flat-panel detectors in X-ray systems].

    PubMed

    Spahn, M; Heer, V; Freytag, R

    2003-05-01

    For all application segments X-ray systems with flat-panel detectors increasingly enter the market. In digital radiography,mammography and cardiologic angiography flat-panel detectors are already well established while they are made ready for market introduction in general angiography and fluoroscopy. Two flat-panel detector technologies are available. One technology is based on an indirect conversion process of X-rays while the other one uses a direct conversion method. For radiography and dynamic applications the indirect method provides substantial advantages, while the direct method has some benefits for mammography. In radiography and mammography flat-panel detectors lead to clear improvements with respect to workflow, image quality and dose reduction potentials. These improvements are fostered by the immediate availability of the image, the large dynamic range and the high sensitivity to X-rays. New applications and the use of complex image processing algorithms have the potential to enlarge the present diagnostic range of applications. Up to now, image intensifiers are still the well-established technology for angiography and fluoroscopy. Nevertheless flat-panel detectors begin to enter this field, especially in cardiologic angiography. Characteristics of flat-panel detectors such as the availability of distortion-free images, the excellent contrast resolution, the large dynamic range, the high sensitivity to X-rays and the usability in magnetic fields provide the basis for improved and new diagnostic and interventional methods.

  8. X-Ray Exam: Hip

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Hip KidsHealth > For Parents > X-Ray Exam: Hip A A A What's in this ... español Radiografía: cadera What It Is A hip X-ray is a safe and painless test that uses ...

  9. X-Ray Exam: Wrist

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Wrist KidsHealth > For Parents > X-Ray Exam: Wrist A A A What's in this ... español Radiografía: muñeca What It Is A wrist X-ray is a safe and painless test that uses ...

  10. X-Ray Exam: Ankle

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Ankle KidsHealth > For Parents > X-Ray Exam: Ankle A A A What's in this ... español Radiografía: tobillo What It Is An ankle X-ray is a safe and painless test that uses ...

  11. X-Ray Exam: Foot

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Foot KidsHealth > For Parents > X-Ray Exam: Foot A A A What's in this ... español Radiografía: pie What It Is A foot X-ray is a safe and painless test that uses ...

  12. X-Ray Exam: Finger

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Finger KidsHealth > For Parents > X-Ray Exam: Finger Print A A A What's in ... español Radiografía: dedo What It Is A finger X-ray is a safe and painless test that uses ...

  13. X-Ray Exam: Foot

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Foot KidsHealth > For Parents > X-Ray Exam: Foot Print A A A What's in ... español Radiografía: pie What It Is A foot X-ray is a safe and painless test that uses ...

  14. X-Ray Exam: Ankle

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Ankle KidsHealth > For Parents > X-Ray Exam: Ankle Print A A A What's in ... español Radiografía: tobillo What It Is An ankle X-ray is a safe and painless test that uses ...

  15. X-Ray Exam: Pelvis

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Pelvis KidsHealth > For Parents > X-Ray Exam: Pelvis Print A A A What's in ... español Radiografía: pelvis What It Is A pelvis X-ray is a safe and painless test that uses ...

  16. Tunable X-ray source

    DOEpatents

    Boyce, James R [Williamsburg, VA

    2011-02-08

    A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

  17. X-ray satellite

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems.

  18. SMM x ray polychromator

    NASA Technical Reports Server (NTRS)

    Saba, J. L. R.

    1993-01-01

    The objective of the X-ray Polychromator (XRP) experiment was to study the physical properties of solar flare plasma and its relation to the parent active region to understand better the flare mechanism and related solar activity. Observations were made to determine the temperature, density, and dynamic structure of the pre-flare and flare plasma as a function of wavelength, space and time, the extent to which the flare plasma departs from thermal equilibrium, and the variation of this departure with time. The experiment also determines the temperature and density structure of active regions and flare-induced changes in the regions.

  19. X-Ray Microdiffraction at Megabar Pressures

    NASA Astrophysics Data System (ADS)

    Mao, H.

    2003-12-01

    High-pressure x-ray diffraction (XRD) provides unique, important sources of structural information of minerals in the Earth's deep interior, but encounters major limitations. The restriction to forward diffraction geometry (2θ less than 90° ) severely limits the accuracy. With the 50-5 μ m size x-ray beam typically used to probe samples at 30-200 GPa, the number of crystals covered by the x-ray beam is often too few for good polycrystalline XRD, but too numerous for single-crystal XRD. Single-crystal XRD method with monochromatic x-ray source and 2-d detector works satisfactorily for crystal size larger than 20 μ m, but when the crystal is significantly less than 5 μ m, the sample signals are often overwhelmed by the background. Energy dispersive XRD with polychromatic x-radiation has been used successfully to determine unit-cell parameters of smaller single crystals, but the intensity information is unusable for structural refinement because this method requires rotation of the small crystal relative to the small x-ray beam. Recent integration of panoramic diamond anvil cell1 (PDAC) with synchrotron x-ray microdiffraction2 (XRMD) method has finally overcome these limitations and can potentially revolutionize the high-pressure XRD field. This XRMD method focuses polychromatic x-radiation to submicrometer size to resolve very small single crystals, and collects Laue spots with a 2-d CCD detector. The PDAC allows complete forward, 90° , and back scatterings, while the background signal is minimized by directing the incident x-ray beam through single-crystal diamonds (i.e., avoiding the beryllium seats and gasket). The incident beam can be changed to monochromatic, tuned through the full energy (wavelength) range, and focused to the identical submicrometer spot for d-spacing determination of each Laue spot. All polychromatic Laue spots are collected simultaneously from the same x-ray sampled volume, thus reliable for structure determination. The development

  20. X-ray lithography source

    DOEpatents

    Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary

    1991-01-01

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

  1. X-ray lithography source

    DOEpatents

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.

    1991-12-31

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and eliminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an excellent moderate-priced X-ray source for lithography. 26 figures.

  2. A 2D imager for X-ray FELs with a 65 nm CMOS readout based on per-pixel signal compression and 10 bit A/D conversion

    NASA Astrophysics Data System (ADS)

    Ratti, L.; Comotti, D.; Fabris, L.; Grassi, M.; Lodola, L.; Malcovati, P.; Manghisoni, M.; Re, V.; Traversi, G.; Vacchi, C.; Rizzo, G.; Batignani, G.; Bettarini, S.; Casarosa, G.; Forti, F.; Giorgi, M.; Morsani, F.; Paladino, A.; Paoloni, E.; Pancheri, L.; Dalla Betta, G.-F.; Mendicino, R.; Verzellesi, G.; Xu, H.; Benkechkache, M. A.

    2016-09-01

    A readout channel for applications to X-ray diffraction imaging at free electron lasers has been developed in a 65 nm CMOS technology. The analog front-end circuit can achieve an input dynamic range of 100 dB by leveraging a novel signal compression technique based on the non-linear features of MOS capacitors. Trapezoidal shaping is accomplished through a transconductor and a switched capacitor circuit, performing gated integration and correlated double sampling. A small area, low power 10 bit successive approximation register (SAR) ADC, operated in a time-interleaved fashion, is used for numerical conversion of the amplitude measurement. Operation at 5 MHz of the analog channel including the shaper was demonstrated. Also, the channel was found to be compliant with single 1 keV photon resolution at 1.25 MHz. The ADC provides a signal-to-noise ratio (SNR) of 56 dB, corresponding to an equivalent number of bits (ENOB) of 9 bits, and a differential non linearity DNL < 1 LSB at a sampling rate slightly larger than 1.8 MHz.

  3. Iso-uncertainty control in an experimental fluoroscopy system

    SciTech Connect

    Siddique, S.; Fiume, E.; Jaffray, D. A.

    2014-12-15

    Purpose: X-ray fluoroscopy remains an important imaging modality in a number of image-guided procedures due to its real-time nature and excellent spatial detail. However, the radiation dose delivered raises concerns about its use particularly in lengthy treatment procedures (>0.5 h). The authors have previously presented an algorithm that employs feedback of geometric uncertainty to control dose while maintaining a desired targeting uncertainty during fluoroscopic tracking of fiducials. The method was tested using simulations of motion against controlled noise fields. In this paper, the authors embody the previously reported method in a physical prototype and present changes to the controller required to function in a practical setting. Methods: The metric for feedback used in this study is based on the trace of the covariance of the state of the system, tr(C). The state is defined here as the 2D location of a fiducial on a plane parallel to the detector. A relationship between this metric and the tube current is first developed empirically. This relationship is extended to create a manifold that incorporates a latent variable representing the estimated background attenuation. The manifold is then used within the controller to dynamically adjust the tube current and maintain a specified targeting uncertainty. To evaluate the performance of the proposed method, an acrylic sphere (1.6 mm in diameter) was tracked at tube currents ranging from 0.5 to 0.9 mA (0.033 s) at a fixed energy of 80 kVp. The images were acquired on a Varian Paxscan 4030A (2048 × 1536 pixels, ∼100 cm source-to-axis distance, ∼160 cm source-to-detector distance). The sphere was tracked using a particle filter under two background conditions: (1) uniform sheets of acrylic and (2) an acrylic wedge. The measured tr(C) was used in conjunction with a learned manifold to modulate the tube current in order to maintain a specified uncertainty as the sphere traversed regions of varying thickness

  4. Hard X-Ray Emission of X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, P.

    1999-01-01

    The primary goal of this proposal was to perform an accurate measurement of the broadband x-ray spectrum of a neutron-star low-mass x-ray binary found in a hard x-ray state. This goal was accomplished using data obtained under another proposal, which has provided exciting new information on the hard x-ray emission of neutron-star low-mass x-ray binaries. In "BeppoSAX Observations of the Atoll X-Ray Binary 4U0614+091", we present our analysis of the spectrum of 4U0614+091 over the energy band from 0.3-150 keV. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. Such a very hard x-ray spectrum has not been previously seen from neutron-star low-mass x-ray binaries. We also detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies. A secondary goal was to measure the timing properties of the x-ray emission from neutronstar low-mass x-ray binaries in their low/hard states.

  5. Refractive Optics for Hard X-ray Transmission Microscopy

    SciTech Connect

    Simon, M.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E.; Ahrens, G.; Voigt, A.

    2011-09-09

    For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation--resulting in apertures greater than 1 mm--and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (<100 nm) full-field imaging. To obtain high image quality at reasonable exposure times, custom-tailored matched pairs of condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

  6. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Stone, Gary F.; Bell, Perry M.; Robinson, Ronald B.; Chornenky, Victor I.

    2002-01-01

    A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

  7. British X-ray astronomy

    NASA Astrophysics Data System (ADS)

    Pounds, K. A.

    1986-09-01

    The development of solar and cosmic X-ray studies in the UK, in particular the Skylark and Ariel programs, is discussed. The characteristics and capabilities of the X-ray emulsion detector developed to monitor the solar X-radiation in the Skylark program, and of the proportional counter spectrometer developed for solar X-ray measurements on the Ariel I satellite are described. The designs and functions of the pin-hole camera, the Bragg crystal spectrometer, and the X-ray spectroheliograph are exmained. The Skylark observations of cosmic X-ray sources and high-resolution solar spectra, and the Ariel 5 data on cosmic X-ray sources are presented. Consideration is given to the Ariel 6, the U.S. Einstein Observatory, Exosat, and ASTRO-C.

  8. Solar X-ray physics

    SciTech Connect

    Bornmann, P.L. )

    1991-01-01

    Research on solar X-ray phenomena performed by American scientists during 1987-1990 is reviewed. Major topics discussed include solar images observed during quiescent times, the processes observed during solar flares, and the coronal, interplanetary, and terrestrial phenomena associated with solar X-ray flares. Particular attention is given to the hard X-ray emission observed at the start of the flare, the energy transfer to the soft X-ray emitting plasma, the late resolution of the flare as observed in soft X-ray, and the rate of occurrence of solar flares as a function of time and latitude. Pertinent aspects of nonflaring, coronal X-ray emission and stellar flares are also discussed. 175 refs.

  9. Topological X-Rays Revisited

    ERIC Educational Resources Information Center

    Lynch, Mark

    2012-01-01

    We continue our study of topological X-rays begun in Lynch ["Topological X-rays and MRI's," iJMEST 33(3) (2002), pp. 389-392]. We modify our definition of a topological magnetic resonance imaging and give an affirmative answer to the question posed there: Can we identify a closed set in a box by defining X-rays to probe the interior and without…

  10. X-Ray Polarization Imaging

    DTIC Science & Technology

    2006-07-01

    anatomic structures. Johns and Yaffe (2), building on the work of Alvarez and Macovski (3) and that of Lehmann et al (4), discuss a method for...sources of contrast related to both the wave and par- ticulate nature of x rays. References 1. Johns PC, Yaffe MJ. X-ray characterization of normal and...application to mammography. Med Phys 1985; 12:289–296. 3. Alvarez RE, Macovski A. Energy-selective reconstructions in x-ray computerized tomography. Phys

  11. A study of scatter in diagnostic X-ray rooms.

    PubMed

    McVey, G; Weatherburn, H

    2004-01-01

    An important part of determining the radiation protection requirements during X-ray room design is the calculation of the amount of scatter inside and outside the planned locations of the shielding barriers. In this work, a Monte Carlo code has been developed to calculate the percentage scatter so that the current data can be consolidated and new data can be provided as required. Calculations have been compared with measurements to show that they are representative of scatter found in X-ray rooms. Scatter from the dose-area product meter and the collimator system were found to provide large contributions to the measured scatter. A fluoroscopy room containing a C-arm X-ray set was modelled with the Monte Carlo code. The scatter dose was calculated at an X-ray room entrance behind the protective screen, acting as a secondary barrier, at the radiographer's console. The variation of scatter with the position of the protective screen was studied. An empirical calculation, which provided reasonable agreement with the Monte Carlo calculations, was found by using new data for the variation of scatter from concrete with field size. If a door was placed in the X-ray room entrance behind the protective screen, the results showed that it would not need to be lead lined.

  12. X-ray Absorption Spectroscopy

    SciTech Connect

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  13. X-ray photonics: Bending X-rays with nanochannels

    NASA Astrophysics Data System (ADS)

    Pelliccia, Daniele

    2016-02-01

    X-ray counterparts of visible light optical elements are notoriously difficult to realize because the refractive index of all materials is close to unity. It has now been demonstrated that curved waveguides fabricated on a silicon chip can channel and deflect X-ray beams by consecutive grazing reflections.

  14. X-Ray Exam: Wrist

    MedlinePlus

    ... tissues and the ends of the forearm bones (radius and ulna) and eight small wrist bones (carpal bones). The X-ray image is black and white. Dense structures that block the passage of the X-ray beam through the body, such as the bones, appear white on the image. Softer ...

  15. X-ray based extensometry

    NASA Technical Reports Server (NTRS)

    Jordan, E. H.; Pease, D. M.

    1988-01-01

    A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

  16. Dual x-ray absorptiometry

    NASA Astrophysics Data System (ADS)

    Altman, Albert; Aaron, Ronald

    2011-04-01

    Dual x-ray absorptiometry is widely used in analyzing body composition and imaging. We discuss the physics of the method and exhibit its limitations and show it is related to the Compton and photoelectric contributions to the x-ray absorption coefficients of materials.

  17. Focusing X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; Juda, Michael; Kolodziejczak, Jeffrey; Murray, Stephen; Petre, Robert; Podgorski, William; Ramsey, Brian; Reid, Paul; Saha, Timo; Wolk, Scott; Troller-McKinstry, Susan; Weisskopf, Martin; Wilke, Rudeger; Zhang, William

    2010-01-01

    During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

  18. X-ray shearing interferometer

    DOEpatents

    Koch, Jeffrey A.

    2003-07-08

    An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

  19. X-Ray Diffraction Apparatus

    NASA Technical Reports Server (NTRS)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  20. X-Ray Tomographic Reconstruction

    SciTech Connect

    Bonnie Schmittberger

    2010-08-25

    Tomographic scans have revolutionized imaging techniques used in medical and biological research by resolving individual sample slices instead of several superimposed images that are obtained from regular x-ray scans. X-Ray fluorescence computed tomography, a more specific tomography technique, bombards the sample with synchrotron x-rays and detects the fluorescent photons emitted from the sample. However, since x-rays are attenuated as they pass through the sample, tomographic scans often produce images with erroneous low densities in areas where the x-rays have already passed through most of the sample. To correct for this and correctly reconstruct the data in order to obtain the most accurate images, a program employing iterative methods based on the inverse Radon transform was written. Applying this reconstruction method to a tomographic image recovered some of the lost densities, providing a more accurate image from which element concentrations and internal structure can be determined.

  1. Template-based CTA X-ray angio rigid registration of coronary arteries in frequency domain

    NASA Astrophysics Data System (ADS)

    Aksoy, Timur; Demirci, Stefanie; Degertekin, Muzaffer; Navab, Nassir; Unal, Gozde

    2013-03-01

    This study performs 3D to 2D rigid registration of segmented pre-operative CTA coronary arteries with a single segmented intra-operative X-ray Angio frame in both frequency and spatial domains for real-time Angiography interventions by C-arm fluoroscopy. Most of the work on rigid registration in literature required a close initial- ization of poses and/or positions because of the abundance of local minima and high complexity that searching algorithms face. This study avoids such setbacks by transforming the projections into translation-invariant Fourier domain for estimating the 3D pose. First, template DRRs as candidate poses of 3D vessels of segmented CTA are produced by rotating the camera (image intensifier) around the DICOM angle values with a wide range as in C-arm setup. We have compared the 3D poses of template DRRs with the real X-ray after equalizing the scales (due to disparities in focal length distances) in 3 domains, namely Fourier magnitude, Fourier phase and Fourier polar. The best pose candidate was chosen by one of the highest similarity measures returned by the methods in these domains. It has been noted in literature that these methods are robust against noise and occlusion which was also validated by our results. Translation of the volume was then recovered by distance-map based BFGS optimization well suited to convex structure of our objective function without local minima due to distance maps. Final results were evaluated in 2D projection space rather than with actual values in 3D due to lack of ground truth, ill-posedness of the problem which we intend to address in future.

  2. Template-based CTA to x-ray angio rigid registration of coronary arteries in frequency domain with automatic x-ray segmentation

    SciTech Connect

    Aksoy, Timur; Unal, Gozde; Demirci, Stefanie; Navab, Nassir; Degertekin, Muzaffer

    2013-10-15

    Purpose: A key challenge for image guided coronary interventions is accurate and absolutely robust image registration bringing together preinterventional information extracted from a three-dimensional (3D) patient scan and live interventional image information. In this paper, the authors present a novel scheme for 3D to two-dimensional (2D) rigid registration of coronary arteries extracted from preoperative image scan (3D) and a single segmented intraoperative x-ray angio frame in frequency and spatial domains for real-time angiography interventions by C-arm fluoroscopy.Methods: Most existing rigid registration approaches require a close initialization due to the abundance of local minima and high complexity of search algorithms. The authors' method eliminates this requirement by transforming the projections into translation-invariant Fourier domain for estimating the 3D pose. For 3D rotation recovery, template Digitally Reconstructed Radiographs (DRR) as candidate poses of 3D vessels of segmented computed tomography angiography are produced by rotating the camera (image intensifier) around the DICOM angle values with a specific range as in C-arm setup. The authors have compared the 3D poses of template DRRs with the segmented x-ray after equalizing the scales in three domains, namely, Fourier magnitude, Fourier phase, and Fourier polar. The best rotation pose candidate was chosen by one of the highest similarity measures returned by the methods in these domains. It has been noted in literature that frequency domain methods are robust against noise and occlusion which was also validated by the authors' results. 3D translation of the volume was then recovered by distance-map based BFGS optimization well suited to convex structure of the authors' objective function without local minima due to distance maps. A novel automatic x-ray vessel segmentation was also performed in this study.Results: Final results were evaluated in 2D projection space for patient data; and

  3. X-ray monitoring optical elements

    SciTech Connect

    Stoupin, Stanislav; Shvydko, Yury; Katsoudas, John; Blank, Vladimir D.; Terentyev, Sergey A.

    2016-12-27

    An X-ray article and method for analyzing hard X-rays which have interacted with a test system. The X-ray article is operative to diffract or otherwise process X-rays from an input X-ray beam which have interacted with the test system and at the same time provide an electrical circuit adapted to collect photoelectrons emitted from an X-ray optical element of the X-ray article to analyze features of the test system.

  4. Low dose tomographic fluoroscopy: 4D intervention guidance with running prior

    SciTech Connect

    Flach, Barbara; Kuntz, Jan; Brehm, Marcus; Kachelrieß, Marc; Kueres, Rolf; Bartling, Sönke

    2013-10-15

    Purpose: Today's standard imaging technique in interventional radiology is the single- or biplane x-ray fluoroscopy which delivers 2D projection images as a function of time (2D+T). This state-of-the-art technology, however, suffers from its projective nature and is limited by the superposition of the patient's anatomy. Temporally resolved tomographic volumes (3D+T) would significantly improve the visualization of complex structures. A continuous tomographic data acquisition, if carried out with today's technology, would yield an excessive patient dose. Recently the authors proposed a method that enables tomographic fluoroscopy at the same dose level as projective fluoroscopy which means that if scanning time of an intervention guided by projective fluoroscopy is the same as that of an intervention guided by tomographic fluoroscopy, almost the same dose is administered to the patient. The purpose of this work is to extend authors' previous work and allow for patient motion during the intervention.Methods: The authors propose the running prior technique for adaptation of a prior image. This adaptation is realized by a combination of registration and projection replacement. In a first step the prior is deformed to the current position via affine and deformable registration. Then the information from outdated projections is replaced by newly acquired projections using forward and backprojection steps. The thus adapted volume is the running prior. The proposed method is validated by simulated as well as measured data. To investigate motion during intervention a moving head phantom was simulated. Real in vivo data of a pig are acquired by a prototype CT system consisting of a flat detector and a continuously rotating clinical gantry.Results: With the running prior technique it is possible to correct for motion without additional dose. For an application in intervention guidance both steps of the running prior technique, registration and replacement, are necessary

  5. Monochromatic x-ray sampling streak imager for fast-ignitor plasma observation

    SciTech Connect

    Tanabe, Minoru; Fujiwara, Takashi; Fujioka, Shinsuke; Nishimura, Hiroaki; Shiraga, Hiroyuki; Azechi, Hiroshi; Mima, Kunioki

    2008-10-15

    Ultrafast two-dimensional (2D) x-ray imaging is required to investigate the dynamics of fast-heated core plasma in inertial confinement fusion research. A novel x-ray imager, consisting of two toroidally bent Bragg crystals and an ultrafast 2D x-ray imaging camera, has been demonstrated. Sequential and 2D monochromatic x-ray images of laser-imploded core plasma were obtained with a temporal resolution of 20 ps, a spatial resolution of 31 {mu}m, and a spectral resolution of over 200, simultaneously.

  6. X-Ray Imaging System

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The FluoroScan Imaging System is a high resolution, low radiation device for viewing stationary or moving objects. It resulted from NASA technology developed for x-ray astronomy and Goddard application to a low intensity x-ray imaging scope. FlouroScan Imaging Systems, Inc, (formerly HealthMate, Inc.), a NASA licensee, further refined the FluoroScan System. It is used for examining fractures, placement of catheters, and in veterinary medicine. Its major components include an x-ray generator, scintillator, visible light image intensifier and video display. It is small, light and maneuverable.

  7. Order of magnitude reduction of fluoroscopic x-ray dose

    NASA Astrophysics Data System (ADS)

    Bal, Abhinav; Robert, Normand; Machan, Lindsay; Deutsch, Meir; Kisselgoff, David; Babyn, Paul; Rowlands, John A.

    2012-03-01

    The role of fluoroscopic imaging is critical for diagnostic and image guided therapy. However, fluoroscopic imaging can require significant radiation leading to increased cancer risk and non-stochastic effects such as radiation burns. Our purpose is to reduce the exposure and dose to the patient by an order of magnitude in these procedures by use of the region of interest method. Method and Materials: Region of interest fluoroscopy (ROIF) uses a partial attenuator. The central region of the image has full exposure while the image periphery, there to provide context only, has a reduced exposure rate. ROIF using a static partial attenuator has been shown in our previous studies to reduce the dose area product (DAP) to the patient by at least 2.5 times. Significantly greater reductions in DAP would require improvements in flat panel detectors performance at low x-ray exposures or a different x-ray attenuation strategy. Thus we have investigated a second, dynamic, approach. We have constructed an x-ray shutter system allowing a normal x-ray exposure in the region of interest while reducing the number of x-ray exposures in the periphery through the rapid introduction, positioning and removal of an x-ray attenuating shutter to block radiation only for selected frames. This dynamic approach eliminates the DQE(0) loss associated with the use of static partial attenuator applied to every frame thus permitting a greater reduction in DAP. Results: We have compared the two methods by modeling and determined their fundamental limits.

  8. X-Ray Exam: Pelvis

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... radiologist (a doctor who is specially trained in reading and interpreting X-ray images). The radiologist will ...

  9. X-Ray Exam: Forearm

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... a radiologist (a doctor who's specially trained in reading and interpreting X-ray images). The radiologist will ...

  10. X-Ray Exam: Finger

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... Results A radiologist, a doctor specially trained in reading and interpreting X-ray images, will look at ...

  11. X-Ray Exam: Forearm

    MedlinePlus

    ... amount of radiation to take a picture of a person's forearm (including the wrist, radius, ulna, and elbow). During the examination, an X-ray machine sends a beam of radiation through the arm, and an ...

  12. Bone X-Ray (Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  13. Abdomen X-Ray (Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  14. X-ray microtomographic scanners

    SciTech Connect

    Syryamkin, V. I. Klestov, S. A.

    2015-11-17

    The article studies the operating procedures of an X-ray microtomographic scanner and the module of reconstruction and analysis 3D-image of a test sample in particular. An algorithm for 3D-image reconstruction based on image shadow projections and mathematical methods of the processing are described. Chapter 1 describes the basic principles of X-ray tomography and general procedures of the device developed. Chapters 2 and 3 are devoted to the problem of resources saving by the system during the X-ray tomography procedure, which is achieved by preprocessing of the initial shadow projections. Preprocessing includes background noise removing from the images, which reduces the amount of shadow projections in general and increases the efficiency of the group shadow projections compression. In conclusion, the main applications of X-ray tomography are presented.

  15. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  16. CELESTIAL X-RAY SOURCES.

    DTIC Science & Technology

    sources, (4) the physical conditions in the pulsating x-ray source in the Crab Nebula , and (5) miscellaneous related topics. A bibliography of all work performed under the contract is given. (Author)

  17. Hard X Rays from Supernova 1993J

    DTIC Science & Technology

    1994-01-01

    extensively observed at many wavelengths and has yielded a wealth of new information about core - collapse supernovae (Wheeler & Filipenko 1994, and references...modelled as the result of a core collapse and subsequent explosion in a red supergiant that had lost almost all of its hydrogen-rich envelope (Nomoto...HARD X RAYS FROM SUPERNOVA 1993J M.D. Leising1, J.D. Kurfess2, D.D. Clayton1, D.A. Grabelsky3, J.E. Grove2, W.N. Johnson2, G.V. Jung4, R.L. Kinzer2

  18. X-ray computed tomography

    NASA Astrophysics Data System (ADS)

    1993-05-01

    The primary advantage of the X-ray computed tomography (XRCT) NDE method is that features are not superposed in the image, thereby rendering them easier to interpret than radiographic projection images. Industrial XRCT systems, unlike medical diagnostic systems, have no size and dosage constraints; they are accordingly used for systems from the scale of gas turbine blades, with hundreds-of-kV energies, to those of the scale of ICBMs, requiring MV-level X-ray energies.

  19. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, S. S.

    1980-01-01

    The current status of the X-ray spectroscopy of celestial X-ray sources, ranging from nearby stars to distant quasars, is reviewed. Particular emphasis is placed on the role of such spectroscopy as a useful and unique tool in the elucidation of the physical parameters of the sources. The spectroscopic analysis of degenerate and nondegenerate stellar systems, galactic clusters and active galactic nuclei, and supernova remnants is discussed.

  20. Electromechanical x-ray generator

    DOEpatents

    Watson, Scott A; Platts, David; Sorensen, Eric B

    2016-05-03

    An electro-mechanical x-ray generator configured to obtain high-energy operation with favorable energy-weight scaling. The electro-mechanical x-ray generator may include a pair of capacitor plates. The capacitor plates may be charged to a predefined voltage and may be separated to generate higher voltages on the order of hundreds of kV in the AK gap. The high voltage may be generated in a vacuum tube.

  1. X-Rays, Pregnancy and You

    MedlinePlus

    ... and Procedures Medical Imaging Medical X-ray Imaging X-Rays, Pregnancy and You Share Tweet Linkedin Pin it ... the decision with your doctor. What Kind of X-Rays Can Affect the Unborn Child? During most x- ...

  2. Reduction of multi-fragment fractures of the distal radius using atlas-based 2D/3D registration

    NASA Astrophysics Data System (ADS)

    Gong, Ren Hui; Stewart, James; Abolmaesumi, Purang

    2009-02-01

    We describe a method to guide the surgical fixation of distal radius fractures. The method registers the fracture fragments to a volumetric intensity-based statistical anatomical atlas of distal radius, reconstructed from human cadavers and patient data, using a few intra-operative X-ray fluoroscopy images of the fracture. No pre-operative Computed Tomography (CT) images are required, hence radiation exposure to patients is substantially reduced. Intra-operatively, each bone fragment is roughly segmented from the X-ray images by a surgeon, and a corresponding segmentation volume is created from the back-projections of the 2D segmentations. An optimization procedure positions each segmentation volume at the appropriate pose on the atlas, while simultaneously deforming the atlas such that the overlap of the 2D projection of the atlas with individual fragments in the segmented regions is maximized. Our simulation results shows that this method can accurately identify the pose of large fragments using only two X-ray views, but for small fragments, more than two X-rays may be needed. The method does not assume any prior knowledge about the shape of the bone and the number of fragments, thus it is also potentially suitable for the fixation of other types of multi-fragment fractures.

  3. Center for X-Ray Optics, 1992

    SciTech Connect

    Not Available

    1993-08-01

    This report discusses the following topics: Center for X-Ray Optics; Soft X-Ray Imaging wit Zone Plate Lenses; Biological X-Ray microscopy; Extreme Ultraviolet Lithography for Nanoelectronic Pattern Transfer; Multilayer Reflective Optics; EUV/Soft X-ray Reflectometer; Photoemission Microscopy with Reflective Optics; Spectroscopy with Soft X-Rays; Hard X-Ray Microprobe; Coronary Angiography; and Atomic Scattering Factors.

  4. Optomechanical design of a high-precision detector robot arm system for x-ray nano-diffraction with x-ray nanoprobe

    NASA Astrophysics Data System (ADS)

    Shu, D.; Kalbfleisch, S.; Kearney, S.; Anton, J.; Chu, Y. S.

    2014-03-01

    Collaboration between Argonne National Laboratory and Brookhaven National Laboratory has created a design for the high-precision detector robot arm system that will be used in the x-ray nano-diffraction experimental station at the Hard X-ray Nanoprobe (HXN) beamline for the NSLS-II project. The robot arm system is designed for positioning and manipulating an x-ray detector in three-dimensional space for nano-diffraction data acquisition with the HXN x-ray microscope. It consists of the following major component groups: a granite base with air-bearing support, a 2-D horizontal base stage, a vertical axis goniometer, a 2-D vertical plane robot arm, a 3-D fast scanning stages group, and a 2-D x-ray pixel detector. The design specifications and unique optomechanical structure of this novel high-precision detector robot arm system will be presented in this paper.

  5. Evaluation of low-dose limits in 3D-2D rigid registration for surgical guidance

    NASA Astrophysics Data System (ADS)

    Uneri, A.; Wang, A. S.; Otake, Y.; Kleinszig, G.; Vogt, S.; Khanna, A. J.; Gallia, G. L.; Gokaslan, Z. L.; Siewerdsen, J. H.

    2014-09-01

    An algorithm for intensity-based 3D-2D registration of CT and C-arm fluoroscopy is evaluated for use in surgical guidance, specifically considering the low-dose limits of the fluoroscopic x-ray projections. The registration method is based on a framework using the covariance matrix adaptation evolution strategy (CMA-ES) to identify the 3D patient pose that maximizes the gradient information similarity metric. Registration performance was evaluated in an anthropomorphic head phantom emulating intracranial neurosurgery, using target registration error (TRE) to characterize accuracy and robustness in terms of 95% confidence upper bound in comparison to that of an infrared surgical tracking system. Three clinical scenarios were considered: (1) single-view image + guidance, wherein a single x-ray projection is used for visualization and 3D-2D guidance; (2) dual-view image + guidance, wherein one projection is acquired for visualization, combined with a second (lower-dose) projection acquired at a different C-arm angle for 3D-2D guidance; and (3) dual-view guidance, wherein both projections are acquired at low dose for the purpose of 3D-2D guidance alone (not visualization). In each case, registration accuracy was evaluated as a function of the entrance surface dose associated with the projection view(s). Results indicate that images acquired at a dose as low as 4 μGy (approximately one-tenth the dose of a typical fluoroscopic frame) were sufficient to provide TRE comparable or superior to that of conventional surgical tracking, allowing 3D-2D guidance at a level of dose that is at most 10% greater than conventional fluoroscopy (scenario #2) and potentially reducing the dose to approximately 20% of the level in a conventional fluoroscopically guided procedure (scenario #3).

  6. Evaluation of low-dose limits in 3D-2D rigid registration for surgical guidance.

    PubMed

    Uneri, A; Wang, A S; Otake, Y; Kleinszig, G; Vogt, S; Khanna, A J; Gallia, G L; Gokaslan, Z L; Siewerdsen, J H

    2014-09-21

    An algorithm for intensity-based 3D-2D registration of CT and C-arm fluoroscopy is evaluated for use in surgical guidance, specifically considering the low-dose limits of the fluoroscopic x-ray projections. The registration method is based on a framework using the covariance matrix adaptation evolution strategy (CMA-ES) to identify the 3D patient pose that maximizes the gradient information similarity metric. Registration performance was evaluated in an anthropomorphic head phantom emulating intracranial neurosurgery, using target registration error (TRE) to characterize accuracy and robustness in terms of 95% confidence upper bound in comparison to that of an infrared surgical tracking system. Three clinical scenarios were considered: (1) single-view image+guidance, wherein a single x-ray projection is used for visualization and 3D-2D guidance; (2) dual-view image+guidance, wherein one projection is acquired for visualization, combined with a second (lower-dose) projection acquired at a different C-arm angle for 3D-2D guidance; and (3) dual-view guidance, wherein both projections are acquired at low dose for the purpose of 3D-2D guidance alone (not visualization). In each case, registration accuracy was evaluated as a function of the entrance surface dose associated with the projection view(s). Results indicate that images acquired at a dose as low as 4 μGy (approximately one-tenth the dose of a typical fluoroscopic frame) were sufficient to provide TRE comparable or superior to that of conventional surgical tracking, allowing 3D-2D guidance at a level of dose that is at most 10% greater than conventional fluoroscopy (scenario #2) and potentially reducing the dose to approximately 20% of the level in a conventional fluoroscopically guided procedure (scenario #3).

  7. X-ray Scintillation in Lead Halide Perovskite Crystals

    PubMed Central

    Birowosuto, M. D.; Cortecchia, D.; Drozdowski, W.; Brylew, K.; Lachmanski, W.; Bruno, A.; Soci, C.

    2016-01-01

    Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (EDBE)PbCl4 hybrid perovskite crystals. X-ray excited thermoluminescence measurements indicate the absence of deep traps and a very small density of shallow trap states, which lessens after-glow effects. All perovskite single crystals exhibit high X-ray excited luminescence yields of >120,000 photons/MeV at low temperature. Although thermal quenching is significant at room temperature, the large exciton binding energy of 2D (EDBE)PbCl4 significantly reduces thermal effects compared to 3D perovskites, and moderate light yield of 9,000 photons/MeV can be achieved even at room temperature. This highlights the potential of 2D metal halide perovskites for large-area and low-cost scintillator devices for medical, security and scientific applications. PMID:27849019

  8. X-ray Scintillation in Lead Halide Perovskite Crystals

    NASA Astrophysics Data System (ADS)

    Birowosuto, M. D.; Cortecchia, D.; Drozdowski, W.; Brylew, K.; Lachmanski, W.; Bruno, A.; Soci, C.

    2016-11-01

    Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (EDBE)PbCl4 hybrid perovskite crystals. X-ray excited thermoluminescence measurements indicate the absence of deep traps and a very small density of shallow trap states, which lessens after-glow effects. All perovskite single crystals exhibit high X-ray excited luminescence yields of >120,000 photons/MeV at low temperature. Although thermal quenching is significant at room temperature, the large exciton binding energy of 2D (EDBE)PbCl4 significantly reduces thermal effects compared to 3D perovskites, and moderate light yield of 9,000 photons/MeV can be achieved even at room temperature. This highlights the potential of 2D metal halide perovskites for large-area and low-cost scintillator devices for medical, security and scientific applications.

  9. Building X-ray Diffraction Calibration Software

    SciTech Connect

    Lande, Joshua; /Marlboro Coll.

    2007-10-31

    X-ray diffraction is a technique used to analyze the structure of crystals. It records the interference pattern created when x-rays travel through a crystal. Three dimensional structure can be inferred from these two dimensional diffraction patterns. Before the patterns can be analyzed, diffraction data must be precisely calibrated. Calibration is used to determine the experimental parameters of the particular experiment. This is done by fitting the experimental parameters to the diffraction pattern of a well understood crystal. Fit2D is a software package commonly used to do this calibration but it leaves much to be desired. In particular, it does not give very much control over the calibration of the data, requires a significant amount of manual input, does not allow for the calibration of highly tilted geometries, does not properly explain the assumptions that it is making, and cannot be modified. We build code to do this calibration while at the same time overcoming the limitations of Fit2D. This paper describes the development of the calibration software and the assumptions that are made in doing the calibration.

  10. Ultraluminous X-ray Sources.

    NASA Astrophysics Data System (ADS)

    Fabrika, S.; Sholukhova, O.; Abolmasov, P.

    2008-12-01

    We discuss a new type of X-ray sources discovered in galaxies -- ultraluminous X-ray sources (ULXs). They are of two order of magnitude brighter in X-rays than the brightest Galactic black holes. Two mod- els of ULXs are discussed: "intermediate mass" black holes, 100 - 10000 solar masses, with standard accretion disks, and "stellar mass" black holes with su- percritical accretion disks like that in the Galactic object SS 433. A study of gas nebulae surrounding these objects gives us a new important information on the central sources. The observed X-ray radiation of ULXs is not enough to power their nebulae. To understand both spectra and power of the nebulae one needs a powerful UV source. The ULXs must be such bright in UV range as they are in X-rays. Spectroscopy of gas filaments surrounding SS 433 proves that the intrinsic face-on luminosity of the supercritical accretion disk in the far UV region to be "sim; 10^40 erg/s. We expect that observations of ULXs with the WSO-UV Observatory, measurements their UV fluxes and spectral slopes solve the problem of ULXs between the two known models of these sources.

  11. X-ray Echo Spectroscopy

    NASA Astrophysics Data System (ADS)

    Shvyd'ko, Yuri

    2016-02-01

    X-ray echo spectroscopy, a counterpart of neutron spin echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a pointlike x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-0.02 meV ultrahigh-resolution IXS applications (resolving power >108 ) with broadband ≃5 - 13 meV dispersing systems are introduced featuring more than 103 signal enhancement. The technique is general, applicable in different photon frequency domains.

  12. Clocking Femtosecond X-Rays

    SciTech Connect

    Cavalieri, A L; Fritz, D M; Lee, S H; Bucksbaum, P H; Reis, D A; Mills, D M; Pahl, R; Rudati, J; Fuoss, P H; Stephenson, G B; Lowney, D P; MacPhee, A G; Weinstein, D; Falcone, R W; Als-Nielsen, J; Blome, C; Ischebeck, R; Schlarb, H; Tschentscher, T; Schneider, J; Sokolowski-Tinten, K; Chapman, H N; Lee, R W; Hansen, T N; Synnergren, O; Larsson, J; Techert, S; Sheppard, J; Wark, J S; Bergh, M; Calleman, C; Huldt, G; der Spoel, D v; Timneanu, N; Hajdu, J; Bong, E; Emma, P; Krejcik, P; Arthur, J; Brennan, S; Gaffney, K J; Lindenberg, A M; Hastings, J B

    2004-10-08

    The Sub-Picosecond Pulse Source (SPPS) at the Stanford Linear Accelerator Center (SLAC) produces the brightest ultrafast x-ray pulses in the world, and is the first to employ compressed femtosecond electron bunches for the x-ray source. Both SPPS and future X-ray Free Electron Lasers (XFEL's) will use precise measurements of individual electron bunches to time the arrival of x-ray pulses for time-resolved experiments. At SPPS we use electro-optic sampling (EOS) to perform these measurements. Here we present the first results using this method. An ultrafast laser pulse (135 fs) passes through an electro-optic crystal adjacent to the electron beam. The refractive index of the crystal is distorted by the strong electromagnetic fields of the ultra-relativistic electrons, and this transient birefringence is imprinted on the laser polarization. A polarizer decodes this signal, producing a time-dependent image of the compressed electron bunch. Our measurements yield the relative timing between an ultrafast optical laser and an ultrafast x-ray pulse to within 60 fs, making it possible to use the SPPS to observe atomic-scale ultrafast dynamics initiated by laser-matter interaction.

  13. X-rays surgical revolution.

    PubMed

    Toledo-Pereyra, Luis H

    2009-01-01

    Wilhelm Roentgen (1845-1923) created a surgical revolution with the discovery of the X-rays in late 1895 and the subsequent introduction of this technique for the management of surgical patients. No other physician or scientist had ever imagined such a powerful and worthwhile discovery. Other scientists paved the way for Roentgen to approach the use of these new X-rays for medical purposes. In this way, initially, and prior to Roentgen, Thompson, Hertz, and Lenard applied themselves to the early developments of this technology. They made good advances but never reached the clearly defined understanding brought about by Roentgen. The use of a Crookes tube, a barium platinocyanide screen, with fluorescent light and the generation of energy to propagate the cathode rays were the necessary elements for the conception of an X-ray picture. On November 8, 1895, Roentgen began his experiments on X-ray technology when he found that some kind of rays were being produced by the glass of the tube opposite to the cathode. The development of a photograph successfully completed this early imaging process. After six intense weeks of research, on December 22, he obtained a photograph of the hand of his wife, the first X-ray ever made. This would be a major contribution to the world of medicine and surgery.

  14. AN X-RAY STUDY OF THE ETHYLENE GLYCOLMONTMORILLONITE COMPLEX.

    DTIC Science & Technology

    SOILS, * MONTMORILLONITE , *GLYCOLS, *X RAY SPECTROSCOPY, X RAY SPECTRA, X RAY SPECTRA, X RAY SPECTRA, CLAY MINERALS, COMPLEX COMPOUNDS, FOURIER ANALYSIS, CRYSTAL STRUCTURE, THERMAL PROPERTIES, MATHEMATICAL MODELS.

  15. X-ray tensor tomography

    NASA Astrophysics Data System (ADS)

    Malecki, A.; Potdevin, G.; Biernath, T.; Eggl, E.; Willer, K.; Lasser, T.; Maisenbacher, J.; Gibmeier, J.; Wanner, A.; Pfeiffer, F.

    2014-02-01

    Here we introduce a new concept for x-ray computed tomography that yields information about the local micro-morphology and its orientation in each voxel of the reconstructed 3D tomogram. Contrary to conventional x-ray CT, which only reconstructs a single scalar value for each point in the 3D image, our approach provides a full scattering tensor with multiple independent structural parameters in each volume element. In the application example shown in this study, we highlight that our method can visualize sub-pixel fiber orientations in a carbon composite sample, hence demonstrating its value for non-destructive testing applications. Moreover, as the method is based on the use of a conventional x-ray tube, we believe that it will also have a great impact in the wider range of material science investigations and in future medical diagnostics. The authors declare no competing financial interests.

  16. Assessment of Restoration Methods of X-Ray Images with Emphasis on Medical Photogrammetric Usage

    NASA Astrophysics Data System (ADS)

    Hosseinian, S.; Arefi, H.

    2016-06-01

    Nowadays, various medical X-ray imaging methods such as digital radiography, computed tomography and fluoroscopy are used as important tools in diagnostic and operative processes especially in the computer and robotic assisted surgeries. The procedures of extracting information from these images require appropriate deblurring and denoising processes on the pre- and intra-operative images in order to obtain more accurate information. This issue becomes more considerable when the X-ray images are planned to be employed in the photogrammetric processes for 3D reconstruction from multi-view X-ray images since, accurate data should be extracted from images for 3D modelling and the quality of X-ray images affects directly on the results of the algorithms. For restoration of X-ray images, it is essential to consider the nature and characteristics of these kinds of images. X-ray images exhibit severe quantum noise due to limited X-ray photons involved. The assumptions of Gaussian modelling are not appropriate for photon-limited images such as X-ray images, because of the nature of signal-dependant quantum noise. These images are generally modelled by Poisson distribution which is the most common model for low-intensity imaging. In this paper, existing methods are evaluated. For this purpose, after demonstrating the properties of medical X-ray images, the more efficient and recommended methods for restoration of X-ray images would be described and assessed. After explaining these approaches, they are implemented on samples from different kinds of X-ray images. By considering the results, it is concluded that using PURE-LET, provides more effective and efficient denoising than other examined methods in this research.

  17. Optimized Detector Angular Configuration Increases the Sensitivity of X-ray Fluorescence Computed Tomography (XFCT).

    PubMed

    Ahmad, Moiz; Bazalova-Carter, Magdalena; Fahrig, Rebecca; Xing, Lei

    2015-05-01

    In this work, we demonstrated that an optimized detector angular configuration based on the anisotropic energy distribution of background scattered X-rays improves X-ray fluorescence computed tomography (XFCT) detection sensitivity. We built an XFCT imaging system composed of a bench-top fluoroscopy X-ray source, a CdTe X-ray detector, and a phantom motion stage. We imaged a 6.4-cm-diameter phantom containing different concentrations of gold solution and investigated the effect of detector angular configuration on XFCT image quality. Based on our previous theoretical study, three detector angles were considered. The X-ray fluorescence detector was first placed at 145 (°) (approximating back-scatter) to minimize scatter X-rays. XFCT image quality was compared to images acquired with the detector at 60 (°) (forward-scatter) and 90 (°) (side-scatter). The datasets for the three different detector positions were also combined to approximate an isotropically arranged detector. The sensitivity was optimized with detector in the 145 (°) back-scatter configuration counting the 78-keV gold Kβ1 X-rays. The improvement arose from the reduced energy of scattered X-ray at the 145 (°) position and the large energy separation from gold K β1 X-rays. The lowest detected concentration in this configuration was 2.5 mgAu/mL (or 0.25% Au with SNR = 4.3). This concentration could not be detected with the 60 (°) , 90 (°) , or isotropic configurations (SNRs = 1.3, 0, 2.3, respectively). XFCT imaging dose of 14 mGy was in the range of typical clinical X-ray CT imaging doses. To our knowledge, the sensitivity achieved in this experiment is the highest in any XFCT experiment using an ordinary bench-top X-ray source in a phantom larger than a mouse ( > 3 cm).

  18. Coherent x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Pitney, John Allen

    Conventional x-ray diffraction has historically been done under conditions such that the measured signal consists of an incoherent addition of scattering which is coherent only on a length scale determined by the properties of the beam. The result of the incoherent summation is a statistical averaging over the whole illuminated volume of the sample, which yields certain kinds of information with a high degree of precision and has been key to the success of x-ray diffraction in a variety of applications. Coherent x-ray scattering techniques, such as coherent x-ray diffraction (CXD) and x-ray intensity fluctuation spectroscopy (XIFS), attempt to reduce or eliminate any incoherent averaging so that specific, local structures couple to the measurement without being averaged out. In the case of XIFS, the result is analogous to dynamical light scattering, but with sensitivity to length scales less than 200 nm and time scales from 10-3 s to 103 s. When combined with phase retrieval, CXD represents an imaging technique with the penetration, in situ capabilities, and contrast mechanisms associated with x-rays and with a spatial resolution ultimately limited by the x-ray wavelength. In practice, however, the spatial resolution of CXD imaging is limited by exposure to about 100 A. This thesis describes CXD measurements of the binary alloy Cu3Au and the adaptation of phase retrieval methods for the reconstruction of real-space images of Cu3Au antiphase domains. The theoretical foundations of CXD are described in Chapter 1 as derived from the kinematical formulation for x-ray diffraction and from the temporal and spatial coherence of radiation. The antiphase domain structure of Cu 3Au is described, along with the associated reciprocal-space structure which is measured by CXD. CXD measurements place relatively stringent requirements on the coherence properties of the beam and on the detection mechanism of the experiment; these requirements and the means by which they have been

  19. Portable X-Ray Device

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Portable x-ray instrument developed by NASA now being produced commercially as an industrial tool may soon find further utility as a medical system. The instrument is Lixiscope - Low Intensity X-Ray Imaging Scope -- a self-contained, battery-powered fluoroscope that produces an instant image through use of a small amount of radioactive isotope. Originally developed by Goddard Space Flight Center, Lixiscope is now being produced by Lixi, Inc. which has an exclusive NASA license for one version of the device.

  20. X-ray emission spectroscopy.

    PubMed

    Bergmann, Uwe; Glatzel, Pieter

    2009-01-01

    We describe the chemical information that can be obtained by means of hard X-ray emission spectroscopy (XES). XES is presented as a technique that is complementary to X-ray absorption spectroscopy (XAS) and that provides valuable information with respect to the electronic structure (local charge- and spin-density) as well as the ligand environment of a 3d transition metal. We address non-resonant and resonant XES and present results that were recorded on Mn model systems and the Mn(4)Ca-cluster in the oxygen evolving complex of photosystem II. A brief description of the instrumentation is given with an outlook toward future developments.

  1. Cosmic X-ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1986-01-01

    The analysis of the beryllium-filtered data from Flight 17.020 was completed. The data base provided by the Wisconsin diffuse X-ray sky survey is being analyzed by correlating the B and C band emission with individual velocity components of neutral hydrogen. Work on a solid state detector to be used in high resolution spectroscopy of diffuse or extend X-ray sources is continuing. A series of 21 cm observations was completed. A paper on the effects of process parameter variation on the reflectivity of sputter-deposited tungsten-carvon multilayers was published.

  2. Compact Flash X-Ray Units

    DTIC Science & Technology

    1995-07-01

    Flash x-ray units are used to diagnose pulsed power driven experiments on the Pegasus machine at Los Alamos. Several unique designs of Marx powered...employing an x-ray tube configuration which allows closely spaced x-ray emitting anodes. These units all emit a 10 ns FWHM x-ray pulse. Their Marx banks

  3. Two-Dimensional X-Ray Grating Interferometer

    SciTech Connect

    Zanette, Irene; Weitkamp, Timm; Donath, Tilman; Rutishauser, Simon; David, Christian

    2010-12-10

    We report on the design and experimental realization of a 2D x-ray grating interferometer. We describe how this interferometer has been practically implemented, discuss its performance, and present multidirectional scattering (dark-field) maps and quantitative phase images that have been retrieved using this device.

  4. X-ray exposure sensor and controller

    NASA Technical Reports Server (NTRS)

    Berdahl, C. Martin (Inventor)

    1977-01-01

    An exposure controller for x-ray equipment is provided, which comprises a portable and accurate sensor which can be placed adjacent to and directly beneath the area of interest of an x-ray plate, and which measures the amount of exposure received by that area, and turns off the x-ray equipment when the exposure for the particular area of interest on the x-ray plate reaches the value which provides an optimal x-ray plate.

  5. Alpha proton x ray spectrometer

    NASA Technical Reports Server (NTRS)

    Rieder, Rudi; Waeke, H.; Economou, T.

    1994-01-01

    Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N, and O at levels above typically 1 percent.

  6. Stellar x-ray flares

    NASA Astrophysics Data System (ADS)

    Haisch, B.; Uchida, Y.; Kosugi, T.; Hudson, H. S.

    1995-01-01

    What is the importance of stellar X-ray flares to astrophysics, or even more, to the world at large? In the case of the Sun, changes in solar activity at the two temporal extremes can have quite significant consequences. Longterm changes in solar activity, such as the Maunder Minimum, can apparently lead to non-negligible alterations of the earth's climate. The extreme short term changes are solar flares, the most energetic of which can cause communications disruptions, power outages and ionizing radiation levels amounting to medical X-ray dosages on long commercial flights and even potentially lethal exposures for unshielded astronauts. Why does the Sun exhibit such behaviour? Even if we had a detailed knowledge of the relevant physical processes on the Sun - which we may be on the way to having in hand as evidenced by these Proceedings- our understanding would remain incomplete in regard to fundamental causation so long as we could not say whether the Sun is, in this respect, unique among the stars. This current paper discusses the stellar x-ray flare detections and astronomical models (quasi-static cooling model and two-ribbon model) that are used to observe the x-ray emission.

  7. Focused X-ray source

    DOEpatents

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Maccagno, P.

    1990-08-21

    Disclosed is an intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator. 8 figs.

  8. Focused X-ray source

    DOEpatents

    Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary I.; Maccagno, Pierre

    1990-01-01

    An intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator.

  9. X-rays and magnetism.

    PubMed

    Fischer, Peter; Ohldag, Hendrik

    2015-09-01

    Magnetism is among the most active and attractive areas in modern solid state physics because of intriguing phenomena interesting to fundamental research and a manifold of technological applications. State-of-the-art synthesis of advanced magnetic materials, e.g. in hybrid structures paves the way to new functionalities. To characterize modern magnetic materials and the associated magnetic phenomena, polarized x-rays have emerged as unique probes due to their specific interaction with magnetic materials. A large variety of spectroscopic and microscopic techniques have been developed to quantify in an element, valence and site-sensitive way properties of ferro-, ferri-, and antiferromagnetic systems, such as spin and orbital moments, and to image nanoscale spin textures and their dynamics with sub-ns time and almost 10 nm spatial resolution. The enormous intensity of x-rays and their degree of coherence at next generation x-ray facilities will open the fsec time window to magnetic studies addressing fundamental time scales in magnetism with nanometer spatial resolution. This review will give an introduction into contemporary topics of nanoscale magnetic materials and provide an overview of analytical spectroscopy and microscopy tools based on x-ray dichroism effects. Selected examples of current research will demonstrate the potential and future directions of these techniques.

  10. Rontgen's Discovery of X Rays

    ERIC Educational Resources Information Center

    Thumm, Walter

    1975-01-01

    Relates the story of Wilhelm Conrad Rontgen and presents one view of the extent to which the discovery of the x-ray was an accident. Reconstructs the sequence of events that led to the discovery and includes photographs of the lab where he worked and replicas of apparatus used. (GS)

  11. Compact x-ray source and panel

    SciTech Connect

    Sampayon, Stephen E.

    2008-02-12

    A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

  12. Digital methods for reducing radiation exposure during medical fluoroscopy

    NASA Astrophysics Data System (ADS)

    Edmonds, Ernest W.; Rowlands, John A.; Hynes, David M.; Toth, B. D.; Porter, Anthony J.

    1990-07-01

    There is increased concern over radiation exposure to the general population from many sources. One of the most significant sources is that received by the patient during medical diagnostic procedures, and of these, the procedure with the greatest potential hazard is fluoroscopy. The legal limit for fluoroscopy in most jurisdictions is SR per minute skin exposure rate. Fluoroscopes are often operated in excess of this figure, and in the case of interventional procedures, fluorocopy times may exceed 20 minutes. With improvements in medical technology these procedures are being performed more often, and also are being carried out on younger age groups. Radiation exposure during fluoroscopy, both to patient and operator, is therefore becoming a matter of increasing concern to regulating authorities, and it is incumbent on us to develop digital technology to minimise the radiation hazard in these procedures. This paper explores the technical options available for radiation exposure reduction, including pulsed fluoroscopy, digital noise reduction, or simple reduction in exposure rate to the x-ray image intensifier. We also discuss educational aspects of fluoroscopy which radiologists should be aware of which can be more important than the technological solutions. A "work in progress" report gives a completely new approach to the implementation of a large number of possible digital algorithms, for the investigation of clinical efficacy.

  13. Method for dose-reduced 3D catheter tracking on a scanning-beam digital x-ray system using dynamic electronic collimation

    PubMed Central

    Dunkerley, David A. P.; Funk, Tobias; Speidel, Michael A.

    2016-01-01

    Scanning-beam digital x-ray (SBDX) is an inverse geometry x-ray fluoroscopy system capable of tomosynthesis-based 3D catheter tracking. This work proposes a method of dose-reduced 3D tracking using dynamic electronic collimation (DEC) of the SBDX scanning x-ray tube. Positions in the 2D focal spot array are selectively activated to create a region-of-interest (ROI) x-ray field around the tracked catheter. The ROI position is updated for each frame based on a motion vector calculated from the two most recent 3D tracking results. The technique was evaluated with SBDX data acquired as a catheter tip inside a chest phantom was pulled along a 3D trajectory. DEC scans were retrospectively generated from the detector images stored for each focal spot position. DEC imaging of a catheter tip in a volume measuring 11.4 cm across at isocenter required 340 active focal spots per frame, versus 4473 spots in full-FOV mode. The dose-area-product (DAP) and peak skin dose (PSD) for DEC versus full field-of-view (FOV) scanning were calculated using an SBDX Monte Carlo simulation code. DAP was reduced to 7.4% to 8.4% of the full-FOV value, consistent with the relative number of active focal spots (7.6%). For image sequences with a moving catheter, PSD was 33.6% to 34.8% of the full-FOV value. The root-mean-squared-deviation between DEC-based 3D tracking coordinates and full-FOV 3D tracking coordinates was less than 0.1 mm. The 3D distance between the tracked tip and the sheath centerline averaged 0.75 mm. Dynamic electronic collimation can reduce dose with minimal change in tracking performance. PMID:27375314

  14. X-ray scatter correction for dual-energy x-ray absorptiometry: compensation of patient's lean/fat composition

    NASA Astrophysics Data System (ADS)

    Dinten, Jean-Marc; Darboux, Michel; Bordy, Thomas; Robert-Coutant, Christine; Gonon, Georges

    2004-05-01

    At CEA-LETI, a DEXA approach for systems using a digital 2D radiographic detector has been developed. It relies on an original X-rays scatter management method, based on a combined use of an analytical model and of scatter calibration data acquired through different thicknesses of Lucite slabs. Since Lucite X-rays interaction properties are equivalent to fat, the approach leads to a scatter flux map representative of a 100% fat region. However, patients" soft tissues are composed of lean and fat. Therefore, the obtained scatter map has to be refined in order to take into account the various fat ratios that can present patients. This refinement consists in establishing a formula relating the fat ratio to the thicknesses of Low and High Energy Lucite slabs leading to same signal level. This proportion is then used to compute, on the basis of X-rays/matter interaction equations, correction factors to apply to Lucite equivalent X-rays scatter map. Influence of fat ratio correction has been evaluated, on a digital 2D bone densitometer, with phantoms composed of a PVC step (simulating bone) and different Lucite/water thicknesses as well as on patients. The results show that our X-rays scatter determination approach can take into account variations of body composition.

  15. Effective X-ray beam size measurements of an X-ray tube and polycapillary X-ray lens system using a scanning X-ray fluorescence method

    NASA Astrophysics Data System (ADS)

    Gherase, Mihai R.; Vargas, Andres Felipe

    2017-03-01

    Size measurements of an X-ray beam produced by an integrated polycapillary X-ray lens (PXL) and X-ray tube system were performed by means of a scanning X-ray fluorescence (SXRF) method using three different metallic wires. The beam size was obtained by fitting the SXRF data with the analytical convolution between a Gaussian and a constant functions. For each chemical element in the wire an effective energy was calculated based on the incident X-ray spectrum and its photoelectric cross section. The proposed method can be used to measure the effective X-ray beam size in XRF microscopy studies.

  16. Center for X-Ray Optics, 1986

    SciTech Connect

    Not Available

    1987-07-01

    The Center for X-Ray Optics has made substantial progress during the past year on the development of very high resolution x-ray technologies, the generation of coherent radiation at x-ray wavelengths, and, based on these new developments, had embarked on several scientific investigations that would not otherwise have been possible. The investigations covered in this report are topics on x-ray sources, x-ray imaging and applications, soft x-ray spectroscopy, synchrotron radiation, advanced light source and magnet structures for undulators and wigglers. (LSP)

  17. Microgap x-ray detector

    DOEpatents

    Wuest, C.R.; Bionta, R.M.; Ables, E.

    1994-05-03

    An x-ray detector is disclosed which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope. 3 figures.

  18. Microgap x-ray detector

    DOEpatents

    Wuest, Craig R.; Bionta, Richard M.; Ables, Elden

    1994-01-01

    An x-ray detector which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope.

  19. Hard X-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.

    1981-01-01

    Past hard X-ray and lower energy satellite instruments are reviewed and it is shown that observation above 20 keV and up to hundreds of keV can provide much valuable information on the astrophysics of cosmic sources. To calculate possible sensitivities of future arrays, the efficiencies of a one-atmosphere inch gas counter (the HEAO-1 A-2 xenon filled HED3) and a 3 mm phoswich scintillator (the HEAO-1 A-4 Na1 LED1) were compared. Above 15 keV, the scintillator was more efficient. In a similar comparison, the sensitivity of germanium detectors did not differ much from that of the scintillators, except at high energies where the sensitivity would remain flat and not rise with loss of efficiency. Questions to be addressed concerning the physics of active galaxies and the diffuse radiation background, black holes, radio pulsars, X-ray pulsars, and galactic clusters are examined.

  20. Development of X-ray Imaging Crystal Spectrometer for KSTAR

    NASA Astrophysics Data System (ADS)

    Lee, S. G.; Bak, J. G.; Bitter, M.; Hill, K.; Nam, U. W.; Kim, Y. J.; Moon, M. K.

    2003-10-01

    The engineering design for two high-resolution X-ray imaging crystal spectrometers, which will be part of the basic diagnostics for the KSTAR tokamak, has been finalized. Each of the spectrometers will consists of a spherically bent crystal and a 10 cm x 30 cm large 2D position-sensitive multi-wire proportional counter. The instruments will provide spatially and temporally resolved spectra of the resonance line of helium-like argon (or krypton) and the associated satellites from multiple lines of sight parallel and perpendicular to the horizontal mid-plane for measurements of the profiles of the ion and electron temperatures, plasma rotation velocity, and ionization equilibrium. A 2D detector with delay-line readout and supporting electronics has been fabricated and calibrated with an X-ray source. The engineering design of the spectrometers and the calibration results of the 2D detector will be presented.

  1. X-Ray-powered Macronovae

    NASA Astrophysics Data System (ADS)

    Kisaka, Shota; Ioka, Kunihito; Nakar, Ehud

    2016-02-01

    A macronova (or kilonova) was observed as an infrared excess several days after the short gamma-ray burst GRB 130603B. Although the r-process radioactivity is widely discussed as an energy source, it requires a huge mass of ejecta from a neutron star (NS) binary merger. We propose a new model in which the X-ray excess gives rise to the simultaneously observed infrared excess via thermal re-emission, and explore what constraints this would place on the mass and velocity of the ejecta. This X-ray-powered model explains both the X-ray and infrared excesses with a single energy source such as the central engine like a black hole, and allows for a broader parameter region than the previous models, in particular a smaller ejecta mass ˜ {10}-3{--}{10}-2{M}⊙ and higher iron abundance mixed as suggested by general relativistic simulations for typical NS-NS mergers. We also discuss the other macronova candidates in GRB 060614 and GRB 080503, and the implications for the search of electromagnetic counterparts to gravitational waves.

  2. X-Ray Crystallography Reagent

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

    2003-01-01

    Microcapsules prepared by encapsulating an aqueous solution of a protein, drug or other bioactive substance inside a semi-permeable membrane by are disclosed. The microcapsules are formed by interfacial coacervation under conditions where the shear forces are limited to 0-100 dynes per square centimeter at the interface. By placing the microcapsules in a high osmotic dewatering solution. the protein solution is gradually made saturated and then supersaturated. and the controlled nucleation and crystallization of the protein is achieved. The crystal-filled microcapsules prepared by this method can be conveniently harvested and stored while keeping the encapsulated crystals in essentially pristine condition due to the rugged. protective membrane. Because the membrane components themselves are x-ray transparent, large crystal-containing microcapsules can be individually selected, mounted in x-ray capillary tubes and subjected to high energy x-ray diffraction studies to determine the 3-D smucture of the protein molecules. Certain embodiments of the microcapsules of the invention have composite polymeric outer membranes which are somewhat elastic, water insoluble, permeable only to water, salts, and low molecular weight molecules and are structurally stable in fluid shear forces typically encountered in the human vascular system.

  3. 2D wavelet-analysis-based calibration technique for flat-panel imaging detectors: application in cone beam volume CT

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Ning, Ruola; Yu, Rongfeng; Conover, David L.

    1999-05-01

    The application of the newly developed flat panel x-ray imaging detector in cone beam volume CT has attracted increasing interest recently. Due to an imperfect solid state array manufacturing process, however, defective elements, gain non-uniformity and offset image unavoidably exist in all kinds of flat panel x-ray imaging detectors, which will cause severe streak and ring artifacts in a cone beam reconstruction image and severely degrade image quality. A calibration technique, in which the artifacts resulting from the defective elements, gain non-uniformity and offset image can be reduced significantly, is presented in this paper. The detection of defective elements is distinctively based upon two-dimensional (2D) wavelet analysis. Because of its inherent localizability in recognizing singularities or discontinuities, wavelet analysis possesses the capability of detecting defective elements over a rather large x-ray exposure range, e.g., 20% to approximately 60% of the dynamic range of the detector used. Three-dimensional (3D) images of a low-contrast CT phantom have been reconstructed from projection images acquired by a flat panel x-ray imaging detector with and without calibration process applied. The artifacts caused individually by defective elements, gain non-uniformity and offset image have been separated and investigated in detail, and the correlation with each other have also been exposed explicitly. The investigation is enforced by quantitative analysis of the signal to noise ratio (SNR) and the image uniformity of the cone beam reconstruction image. It has been demonstrated that the ring and streak artifacts resulting from the imperfect performance of a flat panel x-ray imaging detector can be reduced dramatically, and then the image qualities of a cone beam reconstruction image, such as contrast resolution and image uniformity are improved significantly. Furthermore, with little modification, the calibration technique presented here is also applicable

  4. Real-time pose estimation of devices from x-ray images: Application to x-ray/echo registration for cardiac interventions.

    PubMed

    Hatt, Charles R; Speidel, Michael A; Raval, Amish N

    2016-12-01

    In recent years, registration between x-ray fluoroscopy (XRF) and transesophageal echocardiography (TEE) has been rapidly developed, validated, and translated to the clinic as a tool for advanced image guidance of structural heart interventions. This technology relies on accurate pose-estimation of the TEE probe via standard 2D/3D registration methods. It has been shown that latencies caused by slow registrations can result in errors during untracked frames, and a real-time ( > 15 hz) tracking algorithm is needed to minimize these errors. This paper presents two novel similarity metrics designed for accurate, robust, and extremely fast pose-estimation of devices from XRF images: Direct Splat Correlation (DSC) and Patch Gradient Correlation (PGC). Both metrics were implemented in CUDA C, and validated on simulated and clinical datasets against prior methods presented in the literature. It was shown that by combining DSC and PGC in a hybrid method (HYB), target registration errors comparable to previously reported methods were achieved, but at much higher speeds and lower failure rates. In simulated datasets, the proposed HYB method achieved a median projected target registration error (pTRE) of 0.33 mm and a mean registration frame-rate of 12.1 hz, while previously published methods produced median pTREs greater than 1.5 mm and mean registration frame-rates less than 4 hz. In clinical datasets, the HYB method achieved a median pTRE of 1.1 mm and a mean registration frame-rate of 20.5 hz, while previously published methods produced median pTREs greater than 1.3 mm and mean registration frame-rates less than 12 hz. The proposed hybrid method also had much lower failure rates than previously published methods.

  5. Real-time pose estimation of devices from x-ray images: Application to x-ray/echo registration for cardiac interventions

    PubMed Central

    Hatt, Charles R.; Speidel, Michael A.; Raval, Amish N.

    2016-01-01

    In recent years, registration between x-ray fluoroscopy (XRF) and transesophageal echocardiography (TEE) has been rapidly developed, validated, and translated to the clinic as a tool for advanced image guidance of structural heart interventions. This technology relies on accurate pose-estimation of the TEE probe via standard 2D/3D registration methods. It has been shown that latencies caused by slow registrations can result in errors during untracked frames, and a real-time (> 15 hz) tracking algorithm is needed to minimize these errors. This paper presents two novel similarity metrics designed for accurate, robust, and extremely fast pose-estimation of devices from XRF images: Direct Splat Correlation (DSC) and Patch Gradient Correlation (PGC). Both metrics were implemented in CUDA C, and validated on simulated and clinical datasets against prior methods presented in the literature. It was shown that by combining DSC and PGC in a hybrid method (HYB), target registration errors comparable to previously reported methods were achieved, but at much higher speeds and lower failure rates. In simulated datasets, the proposed HYB method achieved a median projected target registration error (pTRE) of 0.33 mm and a mean registration frame-rate of 12.1 hz, while previously published methods produced median pTREs greater than 1.5 mm and mean registration frame-rates less than 4 hz. In clinical datasets, the HYB method achieved a median pTRE of 1.1 mm and a mean registration frame-rate of 20.5 hz, while previously published methods produced median pTREs greater than 1.3 mm and mean registration frame-rates less than 12 hz. The proposed hybrid method also had much lower failure rates than previously published methods. PMID:27179366

  6. Integration of X-ray and MRI systems

    NASA Astrophysics Data System (ADS)

    Wen, Zhifei

    X-ray fluoroscopic imaging provides two-dimensional (2D) projection images with high temporal and spatial resolutions, while magnetic resonance imaging (MRI) has the ability to image any plane in 3D space with excellent soft tissue contrast and powerful physiological information. Integration of these two complementary imaging modalities can greatly benefit numerous image-guided minimally invasive procedures. At Stanford, an x-ray/MR hybrid system has been developed by placing an x-ray tube and detector inside the magnet of an open-bore interventional MR scanner in a configuration without requiring patient movement. However, the proximity of the two systems can cause one to degrade the performance of the other. The influence on the x-ray system by the MR system mainly results from its magnetic field at the location of the x-ray tube. If the magnetic field is parallel to the axis of the tube, it can change the size and shape of the x-ray focal spot by affecting the trajectories of the primary electrons, and increase the tube output by confining the backscattered electrons. If the magnetic field is misaligned with the tube axis, the electron beam can be deflected. These effects are studied analytically, numerically and experimentally. Experimental data agree well with theoretic analysis and computer simulations. Modifications to the x-ray tube are proposed to make it more robust for working in a misaligned magnetic field. The impact on the MR system from the x-ray system stems from the x-ray detector placed underneath the patient table near the MR imaging volume. Magnetic components inside the detector can be magnetized in the magnetic field and create an additional magnetic field that degrades the field homogeneity of the MR system. We use rare-earth permanent magnets located proximate to the detector to compensate for the unwanted field. The strengths and locations of the magnets are optimized with the measured detector field and the MR image quality is

  7. Aspergillosis - chest x-ray (image)

    MedlinePlus

    ... usually occurs in immunocompromised individuals. Here, a chest x-ray shows that the fungus has invaded the lung ... are usually seen as black areas on an x-ray. The cloudiness on the left side of this ...

  8. Advances in transmission x-ray optics

    SciTech Connect

    Ceglio, N.M.

    1983-01-01

    Recent developments in x-ray optics are reviewed. Specific advances in coded aperture imaging, zone plate lens fabrication, time and space resolved spectroscopy, and CCD x-ray detection are discussed.

  9. Producing X-rays at the APS

    ScienceCinema

    None

    2016-07-12

    An introduction and overview of the Advanced Photon Source at Argonne National Laboratory, the technology that produces the brightest X-ray beams in the Western Hemisphere, and the research carried out by scientists using those X-rays.

  10. Advanced x-ray imaging spectrometer

    NASA Technical Reports Server (NTRS)

    Callas, John L. (Inventor); Soli, George A. (Inventor)

    1998-01-01

    An x-ray spectrometer that also provides images of an x-ray source. Coded aperture imaging techniques are used to provide high resolution images. Imaging position-sensitive x-ray sensors with good energy resolution are utilized to provide excellent spectroscopic performance. The system produces high resolution spectral images of the x-ray source which can be viewed in any one of a number of specific energy bands.

  11. Discovery and development of x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Jeong, Yeuncheol; Yin, Ming; Datta, Timir

    2013-03-01

    In 1912 Max Laue at University of Munich reasoned x-rays to be short wavelength electromagnetic waves and figured interference would occur when scattered off crystals. Arnold Sommerfeld, W. Wien, Ewald and others, raised objections to Laue's idea, but soon Walter Friedrich succeeded in recording x-ray interference patterns off copper sulfate crystals. But the Laue-Ewald's 3-dimensional formula predicted excess spots. Fewer spots were observed. William Lawrence Bragg then 22 year old studying at Cambridge University heard the Munich results from father William Henry Brag, physics professor at Univ of Leeds. Lawrence figured the spots are 2-d interference of x-ray wavelets reflecting off successive atomic planes and derived a simple eponymous equation, the Bragg equation d*sin(theta) = n*lamda. 1913 onward the Braggs dominated the crystallography. Max Laue was awarded the physics Nobel in 1914 and the Braggs shared the same in 1915. Starting with Rontgen's first ever prize in 1901, the importance of x-ray techniques is evident from the four out of a total 16 physics Nobels between 1901-1917. We will outline the historical back ground and importance of x-ray diffraction giving rise to techniques that even in 2013, remain work horses in laboratories all over the globe.

  12. Novel x-ray optics for medical diagnostic techniques

    NASA Astrophysics Data System (ADS)

    Kuyumchyan, A.; Arvanian, V.; Kuyumchyan, D.; Aristov, V.; Shulakov, E.

    2009-08-01

    A new hard X - ray hologram with using crystal Fresnel zone plates (ZP) has been described. An image of Fourier hologram for hard X- ray is presented. X-ray phase contrast methods for medical diagnostics techniques are presented. We have developed an X-ray microscope, based on micro focus source which is capable of high resolution phasecontrast imaging and holograms. We propose a new imaging technique with the x-ray energy 8 keV. The method is expected to have wide applications in imaging of low absorbing samples such as biological and medical tissue. We used FIB to reproduction three dimension structures of damaged spinal cord of rat before and after combined treatment with NT3 and NR2D. PUBLISHER'S NOTE 12/16/09: This SPIE Proceedings paper has been updated with an erratum correcting several issues throughout the paper. The corrected paper was published in place of the earlier version on 9/1/2009. If you purchased the original version of the paper and no longer have access, please contact SPIE Digital Library Customer Service at CustomerService@SPIEDigitalLibrary.org for assistance.

  13. Student X-Ray Fluorescence Experiments

    ERIC Educational Resources Information Center

    Fetzer, Homer D.; And Others

    1975-01-01

    Describes the experimental arrangement for x-ray analysis of samples which involves the following: the radioisotopic x-ray disk source; a student-built fluorescence chamber; the energy dispersive x-ray detector, linear amplifier and bias supply; and a multichannel pulse height analyzer. (GS)

  14. Center for X-ray Optics, 1988

    SciTech Connect

    Not Available

    1989-04-01

    This report briefly reviews the following topics: soft-x-ray imaging; reflective optics for hard x-rays; coherent XUV sources; spectroscopy with x-rays; detectors for coronary artery imaging; synchrotron-radiation optics; and support for the advanced light source.

  15. X-Ray Exam: Cervical Spine

    MedlinePlus

    ... to 2-Year-Old X-Ray Exam: Cervical Spine KidsHealth > For Parents > X-Ray Exam: Cervical Spine A A A What's in this article? What ... Radiografía: columna cervical What It Is A cervical spine X-ray is a safe and painless test ...

  16. Cryotomography x-ray microscopy state

    DOEpatents

    Le Gros, Mark; Larabell, Carolyn A.

    2010-10-26

    An x-ray microscope stage enables alignment of a sample about a rotation axis to enable three dimensional tomographic imaging of the sample using an x-ray microscope. A heat exchanger assembly provides cooled gas to a sample during x-ray microscopic imaging.

  17. X-Ray Exam: Femur (Upper Leg)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Femur (Upper Leg) KidsHealth > For Parents > X-Ray Exam: Femur (Upper Leg) Print A A A ... español Radiografía: fémur What It Is A femur X-ray is a safe and painless test that uses ...

  18. X-Ray Exam: Neck (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Neck KidsHealth > For Parents > X-Ray Exam: Neck Print A A A What's in ... español Radiografía: cuello What It Is A neck X-ray is a safe and painless test that uses ...

  19. X-Ray Exam: Cervical Spine

    MedlinePlus

    ... to 2-Year-Old X-Ray Exam: Cervical Spine KidsHealth > For Parents > X-Ray Exam: Cervical Spine Print A A A What's in this article? ... Radiografía: columna cervical What It Is A cervical spine X-ray is a safe and painless test ...

  20. Chest X-Ray (Chest Radiography)

    MedlinePlus

    ... x-rays. top of page What does the equipment look like? The equipment typically used for chest x-rays consists of ... tube is positioned about six feet away. The equipment may also be arranged with the x-ray ...

  1. Electron beam parallel X-ray generator

    NASA Technical Reports Server (NTRS)

    Payne, P.

    1967-01-01

    Broad X ray source produces a highly collimated beam of low energy X rays - a beam with 2 to 5 arc minutes of divergence at energies between 1 and 6 keV in less than 5 feet. The X ray beam is generated by electron bombardment of a target from a large area electron gun.

  2. X-ray optics: Diamond brilliance

    NASA Astrophysics Data System (ADS)

    Durbin, Stephen M.; Colella, Roberto

    2010-03-01

    Most materials either absorb or transmit X-rays. This is useful for imaging but makes it notoriously difficult to build mirrors for reflective X-ray optics. A demonstration of the high X-ray reflectivity of diamond could provide a timely solution to make the most of the next generation of free-electron lasers.

  3. X-ray imaging with amorphous selenium: Pulse height measurements of avalanche gain fluctuations

    SciTech Connect

    Lui, Brian J. M.; Hunt, D. C.; Reznik, A.; Tanioka, K.; Rowlands, J. A.

    2006-09-15

    Avalanche multiplication in amorphous selenium (a-Se) can provide a large, adjustable gain for active matrix flat panel imagers (AMFPI), enabling quantum noise limited x-ray imaging during both radiography and fluoroscopy. In the case of direct conversion AMFPI, the multiplication factor for each x ray is a function of its depth of interaction, and the resulting variations in gain can reduce the detective quantum efficiency (DQE) of the system. An experimental method was developed to measure gain fluctuations by analyzing images of individual x rays that were obtained using a video camera with an a-Se target operated in avalanche mode. Pulse height spectra (PHS) of the charge produced per x ray were recorded for monoenergetic 30.9, 49.4, and 73.8 keV x-ray sources. The rapid initial decay and long tail of each PHS can be explained by a model in which positive charge dominates the initiation of avalanche. The Swank information factor quantifies the effect of gain fluctuation on DQE and was calculated from the PHS. The information factor was found to be 0.5 for a 25 {mu}m a-Se layer with a maximum gain of {approx}300. Changing the energy of the incident x ray influenced the range of the primary photoelectron and noticeably affected the tail of the experimental PHS, but did not significantly change the avalanche Swank factor.

  4. Investigation of Sandstones Wetting by X-ray Microtomography

    NASA Astrophysics Data System (ADS)

    Marquesa, Leonardo C.; Appoloni, Carlos R.; Fernandes, Jaquiel S.; Nagata, Rodrigo

    2011-08-01

    X-ray microtomography is a non-destructive imaging technique. It consists in cross-sections object reconstruction based in the linear attenuation coefficient maps achieved through the object illuminating by a X-ray beam at different angular positions. It has been used by various researches to supply microstructural informations of materials as ceramic filters, pills, titanium prosthesis and reservoir rocks. An item of great interest has been the characterization of the liquid phase presence in porous space. This paper shows the X-ray microtomography methodology employed to achieve qualitative and quantitative results about Botucatu sandstones wetting. It was used a Skyscan, 1172 model, which employs an X-ray tube with W anode and a cone beam. This laboratory based equipment is able to provide images of until 1 μm spatial resolution. The employed samples were two cores of layered Botucatu sandstone, named ARN1 and ARN 2. These samples were scanned in two situations each one, dried and wet. 2D images, porosity values for each 2D image, total average porosity and pose size distribution for the dried and wet situation were compared. H20-NaCl-KI solution was employed for the samples wetting procedure. The two samples were scanned with 4.84 μm spatial resolution. The total average porosities obtained for ARN1 sample before and after wetting were 4.4±0.7% and 1.8±0.4%, respectively.

  5. Mobile X-Ray Unit.

    DTIC Science & Technology

    1996-10-28

    anode 8 surrounded by a coaxial annulus of stainless steel mesh which 9 serves as the cathode, control electronics, and a plurality of 10 spark gap...34Siemens-tube" configuration. More 7 particularly, the X-ray tube 16 has a conical copper/tungsten 8 anode 28, and a stainless steel mesh punched to...160 and 162 each having a typical diameter of 14 2.75 inches. The conflat flanges 160 and 162 are mated to a 15 stainless steel tube 164 having a

  6. X-ray Spectroscopy of Cooling Cluster

    SciTech Connect

    Peterson, J.R.; Fabian, A.C.; /Cambridge U., Inst. of Astron.

    2006-01-17

    We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is cooling below half the maximum temperature. We review these results, discuss physical models of cooling clusters, and describe the X-ray instrumentation and analysis techniques used to make these observations. We discuss several viable mechanisms designed to cancel or distort the expected process of X-ray cluster cooling.

  7. X-ray transmissive debris shield

    DOEpatents

    Spielman, Rick B.

    1996-01-01

    An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

  8. X-ray transmissive debris shield

    DOEpatents

    Spielman, R.B.

    1996-05-21

    An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

  9. X-ray imaging for palaeontology.

    PubMed

    Hohenstein, P

    2004-05-01

    Few may be aware that X-ray imaging is used in palaeontology and has been used since as early as 1896. The X-raying, preparation and exposure of Hunsrück slate fossils are described. Hospital X-ray machines are used by the author in his work. An X-ray is vital to provide evidence that preparation of a slate is worthwhile as well as to facilitate preparation even if there is little external sign of what lies within. The beauty of the X-ray exposure is an added bonus.

  10. Atmospheric electron x-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Feldman, Jason E. (Inventor); George, Thomas (Inventor); Wilcox, Jaroslava Z. (Inventor)

    2002-01-01

    The present invention comprises an apparatus for performing in-situ elemental analyses of surfaces. The invention comprises an atmospheric electron x-ray spectrometer with an electron column which generates, accelerates, and focuses electrons in a column which is isolated from ambient pressure by a:thin, electron transparent membrane. After passing through the membrane, the electrons impinge on the sample in atmosphere to generate characteristic x-rays. An x-ray detector, shaping amplifier, and multi-channel analyzer are used for x-ray detection and signal analysis. By comparing the resultant data to known x-ray spectral signatures, the elemental composition of the surface can be determined.

  11. Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

    DOEpatents

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2015-03-10

    A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

  12. X-ray lithography using holographic images

    DOEpatents

    Howells, Malcolm R.; Jacobsen, Chris

    1995-01-01

    A non-contact X-ray projection lithography method for producing a desired X-ray image on a selected surface of an X-ray-sensitive material, such as photoresist material on a wafer, the desired X-ray image having image minimum linewidths as small as 0.063 .mu.m, or even smaller. A hologram and its position are determined that will produce the desired image on the selected surface when the hologram is irradiated with X-rays from a suitably monochromatic X-ray source of a selected wavelength .lambda.. On-axis X-ray transmission through, or off-axis X-ray reflection from, a hologram may be used here, with very different requirements for monochromaticity, flux and brightness of the X-ray source. For reasonable penetration of photoresist materials by X-rays produced by the X-ray source, the wavelength X, is preferably chosen to be no more than 13.5 nm in one embodiment and more preferably is chosen in the range 1-5 nm in the other embodiment. A lower limit on linewidth is set by the linewidth of available microstructure writing devices, such as an electron beam.

  13. X-ray omni microscopy.

    PubMed

    Paganin, D; Gureyev, T E; Mayo, S C; Stevenson, A W; Nesterets, Ya I; Wilkins, S W

    2004-06-01

    The science of wave-field phase retrieval and phase measurement is sufficiently mature to permit the routine reconstruction, over a given plane, of the complex wave-function associated with certain coherent forward-propagating scalar wave-fields. This reconstruction gives total knowledge of the information that has been encoded in the complex wave-field by passage through a sample of interest. Such total knowledge is powerful, because it permits the emulation in software of the subsequent action of an infinite variety of coherent imaging systems. Such 'virtual optics', in which software forms a natural extension of the 'hardware optics' in an imaging system, may be useful in contexts such as quantitative atom and X-ray imaging, in which optical elements such as beam-splitters and lenses can be realized in software rather than optical hardware. Here, we develop the requisite theory to describe such hybrid virtual-physical imaging systems, which we term 'omni optics' because of their infinite flexibility. We then give an experimental demonstration of these ideas by showing that a lensless X-ray point projection microscope can, when equipped with the appropriate software, emulate an infinite variety of optical imaging systems including those which yield interferograms, Zernike phase contrast, Schlieren imaging and diffraction-enhanced imaging.

  14. The Rosat x-ray sky

    NASA Astrophysics Data System (ADS)

    Voges, Wolfgang

    1995-01-01

    The ROSAT (Röntgensatellit) X-ray astronomy satellite has completed the first all-sky x-ray and XUV survey with imaging telescopes. About 60 000 new x-ray and 400 new XUV (1) sources were detected. This contribution will deal with preliminary results from the ROSAT ALL-SKY X-RAY SURVEY. The ROSAT diffuse and point-source x-ray skymaps, the positional accuracy obtained for the x-ray sources, and a few results from correlations performed with available catalogues in various energy bands like the Radio, Infrared, Visible, UV, and hard x-rays as well as identifications from optical follow-up observations will be presented.

  15. Spectral slicing X-ray telescope

    NASA Technical Reports Server (NTRS)

    Hoover, R. B.; Shealy, D.; Chao, S.-H.

    1986-01-01

    Layered synthetic microstructure (LSM) X-ray optics is investigated as a system for coupling a conventional glancing incidence X-ray mirror to a high sensitivity X-ray detector. It is shown that, by the use of figured LSM optics, it is possible to magnify the X-ray image produced by the primary mirrors so as to maintain their high inherent spatial resolution. The results of theoretical and design analyses of several spectral slicing X-ray telescope systems that utilize LSM mirrors of hyperboloidal, spherical, ellipsoidal, and constant optical path aspheric configurations are presented. It is shown that the spherical LSM optics are the preferred configuration, yielding subarcsecond performance over the entire field. The Stanford/Marshall Space Flight Center Rocket X-ray Telescope, which will utilize normal incidence LSM optics to couple a Wolter-Schwarzschild primary mirror to high resolution detectors for solar X-ray/EUV studies, is discussed. Design diagrams are included.

  16. X ray imaging microscope for cancer research

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

    1991-01-01

    The NASA technology employed during the Stanford MSFC LLNL Rocket X Ray Spectroheliograph flight established that doubly reflecting, normal incidence multilayer optics can be designed, fabricated, and used for high resolution x ray imaging of the Sun. Technology developed as part of the MSFC X Ray Microscope program, showed that high quality, high resolution multilayer x ray imaging microscopes are feasible. Using technology developed at Stanford University and at the DOE Lawrence Livermore National Laboratory (LLNL), Troy W. Barbee, Jr. has fabricated multilayer coatings with near theoretical reflectivities and perfect bandpass matching for a new rocket borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). Advanced Flow Polishing has provided multilayer mirror substrates with sub-angstrom (rms) smoothnesss for the astronomical x ray telescopes and x ray microscopes. The combination of these important technological advancements has paved the way for the development of a Water Window Imaging X Ray Microscope for cancer research.

  17. Evolution of X-ray astronomy

    NASA Technical Reports Server (NTRS)

    Rossj, B.

    1981-01-01

    The evolution of X-ray astronomy up to the launching of the Einstein observatory is presented. The evaluation proceeded through the following major steps: (1) discovery of an extrasolar X-ray source, Sco X-1, orders of magnitude stronger than astronomers believed might exist; (2) identification of a strong X-ray source with the Crab Nebula; (3) identification of Sco X-1 with a faint, peculiar optical object; (4) demonstration that X-ray stars are binary systems, each consisting of a collapsed object accreting matter from an ordinary star; (5) discovery of X-ray bursts; (6) discovery of exceedingly strong X-ray emission from active galaxies, quasars and clusters of galaxies; (7) demonstration that the principal X-ray source is a hot gas filling the space between galaxies.

  18. Tracking Lung Tumors in Orthogonal X-Rays

    PubMed Central

    2013-01-01

    This paper presents a computationally very efficient, robust, automatic tracking method that does not require any implanted fiducials for low-contrast tumors. First, it generates a set of motion hypotheses and computes corresponding feature vectors in local windows within orthogonal-axis X-ray images. Then, it fits a regression model that maps features to 3D tumor motions by minimizing geodesic distances on motion manifold. These hypotheses can be jointly generated in 3D to learn a single 3D regression model or in 2D through back projection to learn two 2D models separately. Tumor is tracked by applying regression to the consecutive image pairs while selecting optimal window size at every time. Evaluations are performed on orthogonal X-ray videos of 10 patients. Comparative experimental results demonstrate superior accuracy (~1 pixel average error) and robustness to varying imaging artifacts and noise at the same time. PMID:23986789

  19. A statistical model of catheter motion from interventional x-ray images: application to image-based gating

    NASA Astrophysics Data System (ADS)

    Panayiotou, M.; King, A. P.; Ma, Y.; Housden, R. J.; Rinaldi, C. A.; Gill, J.; Cooklin, M.; O'Neill, M.; Rhode, K. S.

    2013-11-01

    The motion and deformation of catheters that lie inside cardiac structures can provide valuable information about the motion of the heart. In this paper we describe the formation of a novel statistical model of the motion of a coronary sinus (CS) catheter based on principal component analysis of tracked electrode locations from standard mono-plane x-ray fluoroscopy images. We demonstrate the application of our model for the purposes of retrospective cardiac and respiratory gating of x-ray fluoroscopy images in normal dose x-ray fluoroscopy images, and demonstrate how a modification of the technique allows application to very low dose scenarios. We validated our method on ten mono-plane imaging sequences comprising a total of 610 frames from ten different patients undergoing radiofrequency ablation for the treatment of atrial fibrillation. For normal dose images we established systole, end-inspiration and end-expiration gating with success rates of 100%, 92.1% and 86.9%, respectively. For very low dose applications, the method was tested on the same ten mono-plane x-ray fluoroscopy sequences without noise and with added noise at signal to noise ratio (SNR) values of √50, √10, √8, √6, √5, √2 and √1 to simulate the image quality of increasingly lower dose x-ray images. The method was able to detect the CS catheter even in the lowest SNR images with median errors not exceeding 2.6 mm per electrode. Furthermore, gating success rates of 100%, 71.4% and 85.7% were achieved at the low SNR value of √2, representing a dose reduction of more than 25 times. Thus, the technique has the potential to extract useful information whilst substantially reducing the radiation exposure.

  20. Chandra ACIS Survey of X-Ray Point Sources in Nearby Galaxies. II. X-Ray Luminosity Functions and Ultraluminous X-Ray Sources

    NASA Astrophysics Data System (ADS)

    Wang, Song; Qiu, Yanli; Liu, Jifeng; Bregman, Joel N.

    2016-09-01

    Based on the recently completed Chandra/ACIS survey of X-ray point sources in nearby galaxies, we study the X-ray luminosity functions (XLFs) for X-ray point sources in different types of galaxies and the statistical properties of ultraluminous X-ray sources (ULXs). Uniform procedures are developed to compute the detection threshold, to estimate the foreground/background contamination, and to calculate the XLFs for individual galaxies and groups of galaxies, resulting in an XLF library of 343 galaxies of different types. With the large number of surveyed galaxies, we have studied the XLFs and ULX properties across different host galaxy types, and confirm with good statistics that the XLF slope flattens from lenticular (α ˜ 1.50 ± 0.07) to elliptical (˜1.21 ± 0.02), to spirals (˜0.80 ± 0.02), to peculiars (˜0.55 ± 0.30), and to irregulars (˜0.26 ± 0.10). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosities for different types of galaxies. A radial dependency is found for ellipticals, with a flatter XLF slope for sources located between D 25 and 2D 25, suggesting the XLF slopes in the outer region of early-type galaxies are dominated by low-mass X-ray binaries in globular clusters. This study shows that the ULX rate in early-type galaxies is 0.24 ± 0.05 ULXs per surveyed galaxy, on a 5σ confidence level. The XLF for ULXs in late-type galaxies extends smoothly until it drops abruptly around 4 × 1040 erg s-1, and this break may suggest a mild boundary between the stellar black hole population possibly including 30 M ⊙ black holes with super-Eddington radiation and intermediate mass black holes.

  1. Laser induced x-ray `RADAR' particle physics model

    NASA Astrophysics Data System (ADS)

    Lockley, D.; Deas, R.; Moss, R.; Wilson, L. A.; Rusby, D.; Neely, D.

    2016-05-01

    images from the modelled data. The simulated images show good agreement with the experimental images both in terms of the temporal and spatial response of the backscattered X-rays. The computer model has also been used to simulate scanning over an area to generate a 3D image of the test objects scanned. Range gating was applied to the simulated 3D data to show how significant signal-to-noise ratio enhancements could be achieved to resulting 2D images when compared to conventional backscatter X-ray images. Further predictions have been made using the computer simulation including the energy distribution of the backscatter X-rays, as well as multi-path and scatter effects not measured in the experiment. Multi-path effects were shown to be the primary contributor to undesirable image artefacts observed in the simulated images. The computer simulation allowed the sources of these artefacts to be identified and highlighted the importance of mitigating these effects in the experiment. These predicted effects could be explored and verified through future experiments. Additionally the model has provided insight into potential performance limitations of the X-ray RADAR concept and informed on possible solutions. Further model developments will include simulating a more realistic electron beam energy distribution and incorporating representative detector characteristics.

  2. Controlling X-rays With Light

    SciTech Connect

    Glover, Ernie; Hertlein, Marcus; Southworth, Steve; Allison, Tom; van Tilborg, Jeroen; Kanter, Elliot; Krassig, B.; Varma, H.; Rude, Bruce; Santra, Robin; Belkacem, Ali; Young, Linda

    2010-08-02

    Ultrafast x-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largelyunexplored area of ultrafast x-ray science is the use of light to control how x-rays interact with matter. In order to extend control concepts established for long wavelengthprobes to the x-ray regime, the optical control field must drive a coherent electronic response on a timescale comparable to femtosecond core-hole lifetimes. An intense field is required to achieve this rapid response. Here an intense optical control pulse isobserved to efficiently modulate photoelectric absorption for x-rays and to create an ultrafast transparency window. We demonstrate an application of x-ray transparencyrelevant to ultrafast x-ray sources: an all-photonic temporal cross-correlation measurement of a femtosecond x-ray pulse. The ability to control x-ray/matterinteractions with light will create new opportunities at current and next-generation x-ray light sources.

  3. Controlling x-rays with light.

    SciTech Connect

    Glover, T. E.; Hertlein, M. P.; Southworth, S. H.; Allison, T. K.; van Tilborg, J.; Kanter, E. P.; Krassig, B.; Varma, H. R.; Rude, B.; Santra, R.; Belkacem, A.; Young, L.; Chemical Sciences and Engineering Division; LBNL; Univ. of California at Berkley; Univ. of Chicago

    2010-01-01

    Ultrafast X-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largely unexplored area of ultrafast X-ray science is the use of light to control how X-rays interact with matter. To extend control concepts established for long-wavelength probes to the X-ray regime, the optical control field must drive a coherent electronic response on a timescale comparable to femtosecond core-hole lifetimes. An intense field is required to achieve this rapid response. Here, an intense optical control pulse is observed to efficiently modulate photoelectric absorption for X-rays and to create an ultrafast transparency window. We demonstrate an application of X-ray transparency relevant to ultrafast X-ray sources: an all-photonic temporal cross-correlation measurement of a femtosecond X-ray pulse. The ability to control X-ray-matter interactions with light will create new opportunities for present and next-generation X-ray light sources.

  4. Controlling X-rays with light

    NASA Astrophysics Data System (ADS)

    Glover, T. E.; Hertlein, M. P.; Southworth, S. H.; Allison, T. K.; van Tilborg, J.; Kanter, E. P.; Krässig, B.; Varma, H. R.; Rude, B.; Santra, R.; Belkacem, A.; Young, L.

    2010-01-01

    Ultrafast X-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largely unexplored area of ultrafast X-ray science is the use of light to control how X-rays interact with matter. To extend control concepts established for long-wavelength probes to the X-ray regime, the optical control field must drive a coherent electronic response on a timescale comparable to femtosecond core-hole lifetimes. An intense field is required to achieve this rapid response. Here, an intense optical control pulse is observed to efficiently modulate photoelectric absorption for X-rays and to create an ultrafast transparency window. We demonstrate an application of X-ray transparency relevant to ultrafast X-ray sources: an all-photonic temporal cross-correlation measurement of a femtosecond X-ray pulse. The ability to control X-ray-matter interactions with light will create new opportunities for present and next-generation X-ray light sources.

  5. Compact Stellar X-ray Sources

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van der Klis, Michiel

    2006-04-01

    1. Accreting neutron stars and black holes: a decade of discoveries D. Psaltis; 2. Rapid X-ray variability M. van der Klis; 3. New views of thermonuclear bursts T. Strohmayer and L. Bildsten; 4. Black hole binaries J. McClintock and R. Remillard; 5. Optical, ultraviolet and infrared observations of X-ray binaries P. Charles and M. Coe; 6. Fast X-ray transients and X-ray flashes J. Heise and J. in 't Zand; 7. Isolated neutron stars V. Kaspi, M. Roberts and A. Harding; 8. Globular cluster X-ray sources F. Verbunt and W. Lewin; 9. Jets from X-ray binaries R. Fender; 10. X-Rays from cataclysmic variables E. Kuulkers, A. Norton, A. Schwope and B. Warner; 11. Super soft sources P. Kahabka and E. van den Heuvel; 12. Compact stellar X-ray sources in normal galaxies G. Fabbiano and N. White; 13. Accretion in compact binaries A. King; 14. Soft gamma repeaters and anomalous X-ray pulsars: magnetar candidates P. Woods and C. Thompson; 15. Cosmic gamma-ray bursts, their afterglows, and their host galaxies K. Hurley, R. Sari and S. Djorgovski; 16. Formation and evolution of compact stellar X-ray sources T. Tauris and E. van den Heuvel.

  6. Compact Stellar X-ray Sources

    NASA Astrophysics Data System (ADS)

    Lewin, Walter; van der Klis, Michiel

    2010-11-01

    1. Accreting neutron stars and black holes: a decade of discoveries D. Psaltis; 2. Rapid X-ray variability M. van der Klis; 3. New views of thermonuclear bursts T. Strohmayer and L. Bildsten; 4. Black hole binaries J. McClintock and R. Remillard; 5. Optical, ultraviolet and infrared observations of X-ray binaries P. Charles and M. Coe; 6. Fast X-ray transients and X-ray flashes J. Heise and J. in 't Zand; 7. Isolated neutron stars V. Kaspi, M. Roberts and A. Harding; 8. Globular cluster X-ray sources F. Verbunt and W. Lewin; 9. Jets from X-ray binaries R. Fender; 10. X-Rays from cataclysmic variables E. Kuulkers, A. Norton, A. Schwope and B. Warner; 11. Super soft sources P. Kahabka and E. van den Heuvel; 12. Compact stellar X-ray sources in normal galaxies G. Fabbiano and N. White; 13. Accretion in compact binaries A. King; 14. Soft gamma repeaters and anomalous X-ray pulsars: magnetar candidates P. Woods and C. Thompson; 15. Cosmic gamma-ray bursts, their afterglows, and their host galaxies K. Hurley, R. Sari and S. Djorgovski; 16. Formation and evolution of compact stellar X-ray sources T. Tauris and E. van den Heuvel.

  7. Accuracy evaluation of an X-ray microtomography system.

    PubMed

    Fernandes, Jaquiel S; Appoloni, Carlos R; Fernandes, Celso P

    2016-06-01

    Microstructural parameter evaluation of reservoir rocks is of great importance to petroleum production companies. In this connection, X-ray computed microtomography (μ-CT) has proven to be a quite useful method for the assessment of rocks, as it provides important microstructural parameters, such as porosity, permeability, pore size distribution and porous phase of the sample. X-ray computed microtomography is a non-destructive technique that enables the reuse of samples already measured and also yields 2-D cross-sectional images of the sample as well as volume rendering. This technique offers an additional advantage, as it does not require sample preparation, of reducing the measurement time, which is approximately one to three hours, depending on the spatial resolution used. Although this technique is extensively used, accuracy verification of measurements is hard to obtain because the existing calibrated samples (phantoms) have large volumes and are assessed in medical CT scanners with millimeter spatial resolution. Accordingly, this study aims to determine the accuracy of an X-ray computed microtomography system using a Skyscan 1172 X-ray microtomograph. To accomplish this investigation, it was used a nylon thread set with known appropriate diameter inserted into a glass tube. The results for porosity size and phase distribution by X-ray microtomography were very close to the geometrically calculated values. The geometrically calculated porosity and the porosity determined by the methodology using the μ-CT was 33.4±3.4% and 31.0±0.3%, respectively. The outcome of this investigation was excellent. It was also observed a small variability in the results along all 401 sections of the analyzed image. Minimum and maximum porosity values between the cross sections were 30.9% and 31.1%, respectively. A 3-D image representing the actual structure of the sample was also rendered from the 2-D images.

  8. Technical advances of interventional fluoroscopy and flat panel image receptor.

    PubMed

    Lin, Pei-Jan Paul

    2008-11-01

    In the past decade, various radiation reducing devices and control circuits have been implemented on fluoroscopic imaging equipment. Because of the potential for lengthy fluoroscopic procedures in interventional cardiovascular angiography, these devices and control circuits have been developed for the cardiac catheterization laboratories and interventional angiography suites. Additionally, fluoroscopic systems equipped with image intensifiers have benefited from technological advances in x-ray tube, x-ray generator, and spectral shaping filter technologies. The high heat capacity x-ray tube, the medium frequency inverter generator with high performance switching capability, and the patient dose reduction spectral shaping filter had already been implemented on the image intensified fluoroscopy systems. These three underlying technologies together with the automatic dose rate and image quality (ADRIQ) control logic allow patients undergoing cardiovascular angiography procedures to benefit from "lower patient dose" with "high image quality." While photoconductor (or phosphor plate) x-ray detectors and signal capture thin film transistor (TFT) and charge coupled device (CCD) arrays are analog in nature, the advent of the flat panel image receptor allowed for fluoroscopy procedures to become more streamlined. With the analog-to-digital converter built into the data lines, the flat panel image receptor appears to become a digital device. While the transition from image intensified fluoroscopy systems to flat panel image receptor fluoroscopy systems is part of the on-going "digitization of imaging," the value of a flat panel image receptor may have to be evaluated with respect to patient dose, image quality, and clinical application capabilities. The advantage of flat panel image receptors has yet to be fully explored. For instance, the flat panel image receptor has its disadvantages as compared to the image intensifiers; the cost of the equipment is probably the most

  9. Diffractive X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  10. Industrial X-Ray Imaging

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In 1990, Lewis Research Center jointly sponsored a conference with the U.S. Air Force Wright Laboratory focused on high speed imaging. This conference, and early funding by Lewis Research Center, helped to spur work by Silicon Mountain Design, Inc. to break the performance barriers of imaging speed, resolution, and sensitivity through innovative technology. Later, under a Small Business Innovation Research contract with the Jet Propulsion Laboratory, the company designed a real-time image enhancing camera that yields superb, high quality images in 1/30th of a second while limiting distortion. The result is a rapidly available, enhanced image showing significantly greater detail compared to image processing executed on digital computers. Current applications include radiographic and pathology-based medicine, industrial imaging, x-ray inspection devices, and automated semiconductor inspection equipment.

  11. Soft x-ray interferometry

    SciTech Connect

    Not Available

    1993-09-01

    The purpose of the soft x-ray interferometry workshop held at Lawrence Berkeley Laboratory was to discuss with the scientific community the proposed technical design of the soft x-ray Fourier-transform spectrometer being developed at the ALS. Different design strategies for the instrument`s components were discussed, as well as detection methods, signal processing issues, and how to meet the manufacturing tolerances that are necessary for the instrument to achieve the desired levels of performance. Workshop participants were encouraged to report on their experiences in the field of Fourier transform spectroscopy. The ALS is developing a Fourier transform spectrometer that is intended to operate up to 100 eV. The motivation is solely improved resolution and not the throughput (Jaquinot) or multiplex (Fellgett) advantage, neither of which apply for the sources and detectors used in this spectral range. The proposed implementation of this is via a Mach-Zehnder geometry that has been (1) distorted from a square to a rhombus to get grazing incidence of a suitable angle for 100 eV and (2) provided with a mirror-motion system to make the path difference between the interfering beams tunable. The experiment consists of measuring the emergent light intensity (I(x)) as a function of the path difference (x). The resolving power of the system is limited by the amount of path difference obtainable that is 1 cm (one million half-waves at 200{angstrom} wavelength) in the design thus allowing a resolving power of one million. The free spectral range of the system is limited by the closeness with which the function I(x) is sampled. It is proposed to illuminate a helium absorption cell with roughly 1%-band-width light from a monochromator thus allowing one hundred aliases without spectral overlap even for sampling of I(x) at one hundredth of the Nyquist frequency.

  12. An experimental measurement of metal multilayer x-ray reflectivity degradation due to intense x-ray flux

    SciTech Connect

    Hockaday, M.Y.P.

    1987-06-01

    The degradation of the x-ray reflection characteristics of metal multilayer Bragg diffractors due to intense x-ray flux was investigated. The Z-pinch plasma produced by PROTO II of Sandia National Laboratories, Albuquerque, New Mexico, was used as the source. The plasma generated total x-ray yields of as much as 40 kJ with up to 15 kJ in the neon hydrogen- and helium-like resonance lines in nominal 20-ns pulses. Molybdenum-carbon, palladium-carbon, and tungsten-carbon metal multilayers were placed at 15 and 150 cm from the plasma center. The multilayers were at nominal angles of 5/sup 0/ and 10/sup 0/ to diffract the neon resonance lines. The time-integrated x-ray reflection of the metal multilayers was monitored by x-ray film. A fluorescer-fiber optic-visible streak camera detector system was then used to monitor the time-resolved x-ray reflection characteristics of 135 A- 2d tungsten-carbon multilayers. A large specular component in the reflectivity prevented determination of the rocking curve of the multilayer. For a neon implosion onto a vanadium-doped polyacrylic acid foam target shot, detailed modeling was attempted. The spectral flux was determined with data from 5 XRD channels and deconvolved using the code SHAZAM. The observed decay in reflectivity was assumed to correspond to the melting of the first tungsten layer. A ''conduction factor'' of 82 was required to manipulate the heat loading of the first tungsten layer such that the time of melting corresponded to the observed decay. The power at destruction was 141 MW/cm/sup 2/ and the integrated energy at destruction was 2.0 J/cm/sup 2/. 82 refs., 66 figs., 10 tabs.

  13. Stimulated Electronic X-Ray Raman Scattering

    NASA Astrophysics Data System (ADS)

    Weninger, Clemens; Purvis, Michael; Ryan, Duncan; London, Richard A.; Bozek, John D.; Bostedt, Christoph; Graf, Alexander; Brown, Gregory; Rocca, Jorge J.; Rohringer, Nina

    2013-12-01

    We demonstrate strong stimulated inelastic x-ray scattering by resonantly exciting a dense gas target of neon with femtosecond, high-intensity x-ray pulses from an x-ray free-electron laser (XFEL). A small number of lower energy XFEL seed photons drive an avalanche of stimulated resonant inelastic x-ray scattering processes that amplify the Raman scattering signal by several orders of magnitude until it reaches saturation. Despite the large overall spectral width, the internal spiky structure of the XFEL spectrum determines the energy resolution of the scattering process in a statistical sense. This is demonstrated by observing a stochastic line shift of the inelastically scattered x-ray radiation. In conjunction with statistical methods, XFELs can be used for stimulated resonant inelastic x-ray scattering, with spectral resolution smaller than the natural width of the core-excited, intermediate state.

  14. The anomalous X-ray pulsars

    NASA Astrophysics Data System (ADS)

    Chen, Rui; Li, Xiangdong

    2002-03-01

    In the last few years it has been recognized that a group of X-ray pulsars have peculiar properties which set them apart from the majority of accreting pulars in X-ray binaries. They are called the Anomalous X-ray Pulsars (AXP). These objects are characterized by very soft X-ray spectra with low and steady X-ray fluxes, narrow-distributed spin periods, steady spin-down, no optical/infrared counterparts. Some of them may associate with supernova remnants. The nature of AXP remains mysterious. It has been suggested that AXP are accreting neutron stars, or solitary "magnetars", neutron stars with super strong magnetic fields (≍1010-1011T). In this paper we review the recent progress in the studies of AXP, and discuss the possible implications from comparison of AXP with other neutron stars, such as radio pulsars, radio quiet X-ray pulsar candidates and soft γ-ray repeaters.

  15. X-ray data booklet. Revision

    SciTech Connect

    Vaughan, D.

    1986-04-01

    A compilation of data is presented. Included are properties of the elements, electron binding energies, characteristic x-ray energies, fluorescence yields for K and L shells, Auger energies, energy levels for hydrogen-, helium-, and neonlike ions, scattering factors and mass absorption coefficients, and transmission bands of selected filters. Also included are selected reprints on scattering processes, x-ray sources, optics, x-ray detectors, and synchrotron radiation facilities. (WRF)

  16. Lobster-Eye X-Ray Astronomy

    SciTech Connect

    Hudec, R.; Pina, L.; Marsikova, V.; Inneman, A.

    2010-07-15

    We report on technical and astrophysical aspects of Lobster-Eye wide-field X-ray telescopes expected to monitor the sky with high sensitivity and angular resolution of order of 1 arcmin. They will contribute essentially to study of various astrophysical objects such as AGN, SNe, Gamma-ray bursts (GRBs), X-ray flashes (XRFs), galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc.

  17. High speed x-ray beam chopper

    DOEpatents

    McPherson, Armon; Mills, Dennis M.

    2002-01-01

    A fast, economical, and compact x-ray beam chopper with a small mass and a small moment of inertia whose rotation can be synchronized and phase locked to an electronic signal from an x-ray source and be monitored by a light beam is disclosed. X-ray bursts shorter than 2.5 microseconds have been produced with a jitter time of less than 3 ns.

  18. UV observations of x ray binaries

    NASA Technical Reports Server (NTRS)

    Raymond, John C.

    1990-01-01

    IUE (International Ultraviolet Explorer) has observed both high and low mass x ray binaries throughout its life. The UV spectra of high mass systems reveal the nature of the massive companion star and the effects of the x ray illumination of the stellar wind. In loss mass systems, the x ray illuminated disk or companion star dominates the UV light. System parameters and the characteristics of the accretion disk can be inferred.

  19. X-ray transmissive debris shield

    DOEpatents

    Spielman, Rick B.

    1994-01-01

    A composite window structure is described for transmitting x-ray radiation and for shielding radiation generated debris. In particular, separate layers of different x-ray transmissive materials are laminated together to form a high strength, x-ray transmissive debris shield which is particularly suited for use in high energy fluences. In one embodiment, the composite window comprises alternating layers of beryllium and a thermoset polymer.

  20. Topological X-Rays and MRIs

    ERIC Educational Resources Information Center

    Lynch, Mark

    2002-01-01

    Let K be a compact subset of the interior of the unit disk D in the plane and suppose one can't see through the boundary of D and identify K. However, assume that one can take "topological X-rays" of D which measure the "density" of K along the lines of the X-rays. By taking these X-rays from all directions, a "topological MRI" is generated for…

  1. Applications of soft x-ray lasers

    SciTech Connect

    Skinner, C.H.

    1993-08-01

    The high brightness and short pulse duration of soft x-ray lasers provide unique advantages for novel applications. Imaging of biological specimens using x-ray lasers has been demonstrated by several groups. Other applications to fields such as chemistry, material science, plasma diagnostics, and lithography are beginning to emerge. We review the current status of soft x-ray lasers from the perspective of applications, and present an overview of the applications currently being developed.

  2. Negative affinity X-ray photocathodes

    NASA Technical Reports Server (NTRS)

    Vanspeybroeck, L.; Kellogg, E.; Murray, S.; Duckett, S.

    1974-01-01

    A new X-ray image intensifier is described. The device should eventually have a quantum efficiency which is an order of magnitude greater than that of presently available high spatial resolution X-ray detectors, such as microchannel plates. The new intesifier is based upon a GaAs crystal photocathode which is activated to achieve negative electron affinity. Details concerning the detector concept are discussed together with the theoretical relations involved, X-ray data, and optical data.

  3. The Overutilization of X-rays

    PubMed Central

    Lyon, W. K.

    1981-01-01

    Within 20 years of Roentgen's discovery of X-rays in 1895, it became apparent that large doses of radiation damaged human tissue.1 Yet the medical profession continues to contribute to the overutilization of X-rays, occasionally spending health care dollars to subject our patients to a health risk. This paper discusses the evidence to support the claim that X-rays are overutilized, and offers recommendations to rectify the situation. PMID:21289771

  4. Observation of femtosecond X-ray interactions with matter using an X-ray-X-ray pump-probe scheme.

    PubMed

    Inoue, Ichiro; Inubushi, Yuichi; Sato, Takahiro; Tono, Kensuke; Katayama, Tetsuo; Kameshima, Takashi; Ogawa, Kanade; Togashi, Tadashi; Owada, Shigeki; Amemiya, Yoshiyuki; Tanaka, Takashi; Hara, Toru; Yabashi, Makina

    2016-02-09

    Resolution in the X-ray structure determination of noncrystalline samples has been limited to several tens of nanometers, because deep X-ray irradiation required for enhanced resolution causes radiation damage to samples. However, theoretical studies predict that the femtosecond (fs) durations of X-ray free-electron laser (XFEL) pulses make it possible to record scattering signals before the initiation of X-ray damage processes; thus, an ultraintense X-ray beam can be used beyond the conventional limit of radiation dose. Here, we verify this scenario by directly observing femtosecond X-ray damage processes in diamond irradiated with extraordinarily intense (∼10(19) W/cm(2)) XFEL pulses. An X-ray pump-probe diffraction scheme was developed in this study; tightly focused double-5-fs XFEL pulses with time separations ranging from sub-fs to 80 fs were used to excite (i.e., pump) the diamond and characterize (i.e., probe) the temporal changes of the crystalline structures through Bragg reflection. It was found that the pump and probe diffraction intensities remain almost constant for shorter time separations of the double pulse, whereas the probe diffraction intensities decreased after 20 fs following pump pulse irradiation due to the X-ray-induced atomic displacement. This result indicates that sub-10-fs XFEL pulses enable conductions of damageless structural determinations and supports the validity of the theoretical predictions of ultraintense X-ray-matter interactions. The X-ray pump-probe scheme demonstrated here would be effective for understanding ultraintense X-ray-matter interactions, which will greatly stimulate advanced XFEL applications, such as atomic structure determination of a single molecule and generation of exotic matters with high energy densities.

  5. Ultrashort X-ray pulse science

    SciTech Connect

    Chin, Alan Hap

    1998-05-01

    A variety of phenomena involves atomic motion on the femtosecond time-scale. These phenomena have been studied using ultrashort optical pulses, which indirectly probe atomic positions through changes in optical properties. Because x-rays can more directly probe atomic positions, ultrashort x-ray pulses are better suited for the study of ultrafast structural dynamics. One approach towards generating ultrashort x-ray pulses is by 90° Thomson scattering between terawatt laser pulses and relativistic electrons. Using this technique, the author generated ~ 300 fs, 30 keV (0.4 Å) x-ray pulses. These x-ray pulses are absolutely synchronized with ultrashort laser pulses, allowing femtosecond optical pump/x-ray probe experiments to be performed. Using the right-angle Thomson scattering x-ray source, the author performed time-resolved x-ray diffraction studies of laser-perturbated InSb. These experiments revealed a delayed onset of lattice expansion. This delay is due to the energy relaxation from a dense electron-hole plasma to the lattice. The dense electron-hole plasma first undergoes Auger recombination, which reduces the carrier concentration while maintaining energy content. Longitudinal-optic (LO) phonon emission then couples energy to the lattice. LO phonon decay into acoustic phonons, and acoustic phonon propagation then causes the growth of a thermally expanded layer. Source characterization is instrumental in utilizing ultrashort x-ray pulses in time-resolved x-ray spectroscopies. By measurement of the electron beam diameter at the generation point, the pulse duration of the Thomson scattered x-rays is determined. Analysis of the Thomson scattered x-ray beam properties also provides a novel means of electron bunch characterization. Although the pulse duration is inferred for the Thomson scattering x-ray source, direct measurement is required for other x-ray pulse sources. A method based on the laser-assisted photoelectric effect (LAPE) has been demonstrated as a

  6. X-rays from the youngest stars

    NASA Technical Reports Server (NTRS)

    Feigelson, Eric D.

    1994-01-01

    The X-ray properties of classical and weak-lined T Tauri stars are briefly reviewed, emphasizing recent results from the ROSAT satellite and prospects for ASCA. The interpretation of the high level of T Tauri X-rays as enhanced solar-type magnetic activity is discussed and criticized. The census of X-ray emitters is significantly increasing estimates of galactic star formation efficiency, and X-ray emission may be important for self-regulation of star formation. ASCA images will detect star formation regions out to several kiloparsecs and will study the magnetically heated plasma around T Tauri stars. However, images will often suffer from crowding effects.

  7. Separating Peaks in X-Ray Spectra

    NASA Technical Reports Server (NTRS)

    Nicolas, David; Taylor, Clayborne; Wade, Thomas

    1987-01-01

    Deconvolution algorithm assists in analysis of x-ray spectra from scanning electron microscopes, electron microprobe analyzers, x-ray fluorescence spectrometers, and like. New algorithm automatically deconvolves x-ray spectrum, identifies locations of spectral peaks, and selects chemical elements most likely producing peaks. Technique based on similarities between zero- and second-order terms of Taylor-series expansions of Gaussian distribution and of damped sinusoid. Principal advantage of algorithm: no requirement to adjust weighting factors or other parameters when analyzing general x-ray spectra.

  8. Bent crystal X-ray topography

    NASA Technical Reports Server (NTRS)

    Parker, D. L.

    1978-01-01

    A television X-ray topographic camera system was constructed. The system differs from the previous system in that it incorporates the X-ray TV imaging system and has a semi-automatic wafer loading system. Also the X-ray diffraction is in a vertical plane. This feature makes wafer loading easier and makes the system compatible with any commercial X-ray generating system. Topographs and results obtained from a study of the diffraction contrast variation with impurity concentration for both boron implanted and boron diffused silicon are included.

  9. Symbiotic Stars in X-rays

    NASA Technical Reports Server (NTRS)

    Luna, G. J. M.; Sokoloski, J. L.; Mukai, K.; Nelson, T.

    2014-01-01

    Until recently, symbiotic binary systems in which a white dwarf accretes from a red giant were thought to be mainly a soft X-ray population. Here we describe the detection with the X-ray Telescope (XRT) on the Swift satellite of 9 white dwarf symbiotics that were not previously known to be X-ray sources and one that was previously detected as a supersoft X-ray source. The 9 new X-ray detections were the result of a survey of 41 symbiotic stars, and they increase the number of symbiotic stars known to be X-ray sources by approximately 30%. Swift/XRT detected all of the new X-ray sources at energies greater than 2 keV. Their X-ray spectra are consistent with thermal emission and fall naturally into three distinct groups. The first group contains those sources with a single, highly absorbed hard component, which we identify as probably coming from an accretion-disk boundary layer. The second group is composed of those sources with a single, soft X-ray spectral component, which likely arises in a region where low-velocity shocks produce X-ray emission, i.e. a colliding-wind region. The third group consists of those sources with both hard and soft X-ray spectral components. We also find that unlike in the optical, where rapid, stochastic brightness variations from the accretion disk typically are not seen, detectable UV flickering is a common property of symbiotic stars. Supporting our physical interpretation of the two X-ray spectral components, simultaneous Swift UV photometry shows that symbiotic stars with harder X-ray emission tend to have stronger UV flickering, which is usually associated with accretion through a disk. To place these new observations in the context of previous work on X-ray emission from symbiotic stars, we modified and extended the alpha/beta/gamma classification scheme for symbiotic-star X-ray spectra that was introduced by Muerset et al. based upon observations with the ROSAT satellite, to include a new sigma classification for sources with

  10. X-ray laser microscope apparatus

    DOEpatents

    Suckewer, Szymon; DiCicco, Darrell S.; Hirschberg, Joseph G.; Meixler, Lewis D.; Sathre, Robert; Skinner, Charles H.

    1990-01-01

    A microscope consisting of an x-ray contact microscope and an optical microscope. The optical, phase contrast, microscope is used to align a target with respect to a source of soft x-rays. The source of soft x-rays preferably comprises an x-ray laser but could comprise a synchrotron or other pulse source of x-rays. Transparent resist material is used to support the target. The optical microscope is located on the opposite side of the transparent resist material from the target and is employed to align the target with respect to the anticipated soft x-ray laser beam. After alignment with the use of the optical microscope, the target is exposed to the soft x-ray laser beam. The x-ray sensitive transparent resist material whose chemical bonds are altered by the x-ray beam passing through the target mater GOVERNMENT LICENSE RIGHTS This invention was made with government support under Contract No. De-FG02-86ER13609 awarded by the Department of Energy. The Government has certain rights in this invention.

  11. X-rays from stellar flares

    NASA Technical Reports Server (NTRS)

    Linsky, Jeffrey L.

    1991-01-01

    A summary of X-ray observations of flares on dMe, active spectroscopic binaries and young stars is presented. Consideration is given to the energy associated with the X-ray emission and its relation to other components of the flare energy budget, the time behavior of the flaring plasma as seen by the X-ray emission, and comparisons of stellar flare parameters with solar compact and two ribbon flares. Flares are easily detected when the contrast in the emission from the flaring plasma relative to the stellar photosphere is large as in the X-ray, microwave, and UV regions of the spectrum.

  12. Colloid Coalescence with Focused X Rays

    SciTech Connect

    Weon, B. M.; Kim, J. T.; Je, J. H.; Yi, J. M.; Wang, S.; Lee, W.-K.

    2011-07-01

    We show direct evidence that focused x rays enable us to merge polymer colloidal particles at room temperature. This phenomenon is ascribed to the photochemical scission of colloids with x rays, reducing the molecular weight, glass transition temperature, surface tension, and viscosity of colloids. The observation of the neck bridge growth with time shows that the x-ray-induced colloid coalescence is analogous to viscoelastic coalescence. This finding suggests a feasible protocol of photonic nanofabrication by sintering or welding of polymers, without thermal damage, using x-ray photonics.

  13. Compound refractive X-ray lens

    DOEpatents

    Nygren, David R.; Cahn, Robert; Cederstrom, Bjorn; Danielsson, Mats; Vestlund, Jonas

    2000-01-01

    An apparatus and method for focusing X-rays. In one embodiment, his invention is a commercial-grade compound refractive X-ray lens. The commercial-grade compound refractive X-ray lens includes a volume of low-Z material. The volume of low-Z material has a first surface which is adapted to receive X-rays of commercially-applicable power emitted from a commercial-grade X-ray source. The volume of low-Z material also has a second surface from which emerge the X-rays of commercially-applicable power which were received at the first surface. Additionally, the commercial-grade compound refractive X-ray lens includes a plurality of openings which are disposed between the first surface and the second surface. The plurality of openings are oriented such that the X-rays of commercially-applicable power which are received at the first surface, pass through the volume of low-Z material and through the plurality openings. In so doing, the X-rays which emerge from the second surface are refracted to a focal point.

  14. An Imaging X-Ray Polarimetry Mission

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Bellazini, Ronaldo; Costa, Enrico; Ramsey, Brian; O'Dell, Steve; Tennant, Allyn; Elsner, Ronald; Pavlov, George; Matt, Girogio; Kaspi, Vicky; Coppi, Paolo; Wu, Kinwah; Siegmund, Oswald

    2008-01-01

    Technical progress both in x-ray optics and in polarization-sensitive x-ray detectors, which our groups have pioneered, enables a scientifically powerful - yet inexpensive - dedicated mission for imaging x-ray polarimetry. Such a mission is sufficiently sensitive to measure x-ray (linear) polarization for a broad range of cosmic sources --- particularly those involving neutron stars, stellar black holes, and supermassive black holes (active galactic nuclei). We describe the technical elements, discuss a mission concept, and synopsiz:e the important physical and astrophysical questions such as mission would address.

  15. An Imaging X-Ray Polarimetry Mission

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Bellazini, Ronaldo; Costa, Enrico; Ramsey, Brian; O'Dell, Steve; Elsner, Ronald; Pavlov, George; Matt, Giorgio; Kaspi, Victoria; Tennant, Allyn; Coppi, Paolo; Wu, Kinwah; Siegmund, Oswald

    2008-01-01

    Technical progress both in x-ray optics and in polarization-sensitive x-ray detectors, which our groups have pioneered, enables a scientifically powerful---yet inexpensive---dedicated mission for imaging x-ray polarimetry. Such a mission is sufficiently sensitive to measure x-ray (linear) polarization for a broad range of cosmic sources --particularly those involving neutron stars, stellar black holes, and supermassive black holes (active galactic nuclei). We describe the technical elements, discuss a mission concept, and synopsize the important physical and astrophysical questions such a mission would address.

  16. Quality control phantom for flat panel detector X-ray systems.

    PubMed

    Chida, Koichi; Kaga, Yuji; Haga, Yoshihiro; Takeda, Ken; Zuguchi, Masayuki

    2013-01-01

    X-ray equipment should be routinely checked for optimal imaging performance and appropriate radiation dose. Recently, the use of diagnostic x-ray equipment with flat panel detectors (FPDs) has increased instead of image intensifier (II) and/or screen film systems. In addition, it is necessary to maintain the performance of FPD systems. Unfortunately, no simple quality control (QC) phantom is available for easy evaluation of FPD image performance. This manuscript suggests a novel simple and inexpensive QC phantom for radiography and fluoroscopy. The authors made a new QC phantom for FPD systems to evaluate the spatial resolution, low-contrast resolution, and dynamic range on single (one-shot) x-ray exposures. The phantom consists of three copper thicknesses (0.5, 1.5, and 3.0 mm), an aluminum stepwedge (0.1-2.7 mm), and piano wire of various diameters (0.08-0.5 mm). They also performed an initial check of the new phantom using a FPD system (fluoroscopic and radiographic images). The new phantom is simple and inexpensive to make. This simple phantom is very useful for QC of FPD systems because a visual evaluation of image performance in three thicknesses of copper (low, intermediate, and high attenuation) is readily available with a single exposure. This simple method for daily checking of FPD systems (radiography and fluoroscopy) using the phantom constitutes an easy way to routinely check image performance and will be useful for QC.

  17. Planetary X-rays: Relationship with solar X-rays and solar wind

    NASA Astrophysics Data System (ADS)

    Bhardwaj, A.

    Recently X-ray flares are observed from the low-latitude disk of giant planets Jupiter and Saturn in the energy range of 0.2-2 keV. These flares are found to occur in tandem with the occurrence of solar X-ray flare, when light travel time delay is accounted. These studies suggest that disk of outer planets Jupiter and Saturn acts as "diffuse mirror" for solar X-rays and that X-rays from these planets can be used to study flaring on the hemisphere of the Sun that in invisible to near-Earth space weather satellites. Also by proper modeling of the observed planetary X-rays the solar soft X-ray flux can be derived. X-ray flares are also observed on the Mars. On the other hand, X-rays from comets are produced mainly in charge exchange interaction between highly ionized heavy solar wind ions and cometary neutrals. Thus cometary X-rays provide a diagnostics of the solar wind properties. X-rays from Martian exosphere is also dominantly produced via charge exchange interaction between Martian corona and solar wind, providing proxy for solar wind. This paper provides a brief overview on the X-rays from some of the planets and comets and their connection with solar X-rays and solar wind, and how planetary X-rays can be used to study the Sun.

  18. X-Ray Imaging Study

    NASA Technical Reports Server (NTRS)

    OBrien, Susan K.; Workman, Gary L.

    1996-01-01

    The space environment in which the Space Station Freedom and other space platforms will orbit is truly a hostile environment. For example, the currently estimated integral fluence for electrons above 1 Mev at 2000 nautical miles is above 2 x 1O(exp 10) electrons/sq cm/day and the proton integral fluence is above 1 x 10(exp 9) protons/sq cm/day. At the 200 - 400 nautical miles, which is more representative of the altitude which will provide the environment for the Space Station, each of these fluences will be proportionally less; however, the data indicates that the radiation environment will obviously have an effect on structural materials exposed to the environment for long durations. The effects of this combined environment is the issue which needs to be understood for the long term exposure of structures in space. At the same time, there will be substantial potential for collisions between the space platforms and space debris. The current NASA catalogue contains over 4500 objects floating in space which are not considered payloads. This debris can have significant effects on collision with orbiting spacecraft. In order to better understand the effect of these hostile phenomena on spacecraft, several types of studies are being performed to simulate at some level the effect of the environment. In particular the study of debris clouds produced by hypervelocity impact on the various surfaces anticipated on the Space Station is very important at this point in time. The need to assess the threat of such debris clouds on space structures is an on-going activity. The Space Debris Impact facility in Building 4612 provides a test facility to monitor the types of damage produced with hypervelocity impact. These facilities are used to simulate space environmental effects from energetic particles. Flash radiography or x-ray imaging has traditionally provided such information and as such has been an important tool for recording damage in situ with the event. The proper

  19. X-rays from Saturn Pose Puzzles

    NASA Astrophysics Data System (ADS)

    2004-03-01

    The first clear detection of X-rays from the giant, gaseous planet Saturn has been made with NASA's Chandra X-ray Observatory. Chandra's image shows that the X-rays are concentrated near Saturn's equator, a surprising result since Jupiter's X-ray emission is mainly concentrated near the poles. Existing theories cannot easily explain the intensity or distribution of Saturn's X-rays. Chandra observed Saturn for about 20 hours in April of 2003. The spectrum, or distribution with energy of the X-rays, was found to be very similar to that of X-rays from the Sun. "This indicates that Saturn's X-ray emission is due to the scattering of solar X-rays by Saturn's atmosphere," said Jan-Uwe Ness, of the University of Hamburg in Germany and lead author of a paper discussing the Saturn results in an upcoming issue of Astronomy & Astrophysics. "It's a puzzle, since the intensity of Saturn's X-rays requires that Saturn reflects X-rays fifty times more efficiently than the Moon." The observed 90 megawatts of X-ray power from Saturn's equatorial region is roughly consistent with previous observations of the X-radiation from Jupiter's equatorial region. This suggests that both giant, gaseous planets reflect solar X-rays at unexpectedly high rates. Further observations of Jupiter will be needed to test this possibility. The weak X-radiation from Saturn's south-polar region presents another puzzle (the north pole was blocked by Saturn's rings during this observation). Saturn's magnetic field, like that of Jupiter, is strongest near the poles. X-radiation from Jupiter is brightest at the poles because of auroral activity due to the enhanced interaction of high-energy particles from the Sun with its magnetic field. Since spectacular ultraviolet polar auroras have been observed to occur on Saturn, Ness and colleagues expected that Saturn's south pole might be bright in X-rays. It is not clear whether the auroral mechanism does not produce X-rays on Saturn, or for some reason concentrates

  20. Digital X-Ray Imaging

    NASA Astrophysics Data System (ADS)

    Dance, David R.

    The use of X-ray image receptors that produce a digital image is becoming increasingly important. Possible benefits include improved dynamic range and detective quantum efficiency, improved detectability for objects of low intrinsic contrast, and reduced radiation dose. The image can be available quickly. The display is separated from the image capture so that processing and contrast adjustment are possible before the image is viewed. The availability of a digital image means ready input into PACS and opens up the possibility of computer-aided detection and classification of abnormality. Possible drawbacks of digital systems include high cost, limited high contrast resolution and the fact that their clinical value is sometimes not proven in comparison with conventional, analogue techniques. The high contrast resolution attainable with such systems is discussed and the problem of sampling limitations and aliasing considered. The properties and limitations of digital systems using computed radiography, caesium iodide plus CCDs and active matrix arrays with either caesium iodide or selenium detectors are demonstrated. Examples are given of digital systems for mammography and general radiography and their performance is demonstrated in terms of clinical assessment and measurements of the modulation transfer function and detective quantum efficiency.

  1. SMM X-ray polychromator

    NASA Technical Reports Server (NTRS)

    Strong, Keith T.; Haisch, Bernhard M. (Compiler); Lemen, James R. (Compiler); Acton, L. W.; Bawa, H. S.; Claflin, E. S.; Freeland, S. L.; Slater, G. L.; Kemp, D. L.; Linford, G. A.

    1988-01-01

    The range of observing and analysis programs accomplished with the X-Ray Polychromator (XRP) instruments during the decline of solar cycle 21 and the rise of the solar cycle 22 is summarized. Section 2 describes XRP operations and current status. This is meant as a guide on how the instrument is used to obtain data and what its capabilities are for potential users. The science section contains a series of representative abstracts from recently published papers on major XRP science topics. It is not meant to be a complete list but illustrates the type of science that can come from the analysis of the XRP data. There then follows a series of appendixes that summarize the major data bases that are available. Appendix A is a complete bibliography of papers and presentations produced using XRP data. Appendix B lists all the spectroscopic data accumulated by the Flat Crystal Spectrometer (FCS). Appendix C is a compilation of the XRP flare catalogue for events equivalent to a GOES C-level flare or greater. It lists the start, peak and end times as well as the peak Ca XIX flux.

  2. Hard X ray imaging telescope

    NASA Astrophysics Data System (ADS)

    Lubin, P.

    1990-03-01

    This final report covers the work carried out under the LLNL Contract Number B063682, Subcontractor Regents University of California at Santa Barbara. The research carried out under this contract involves the construction of a telemetry, target acquisition and guidance system, and of a light-weight gondola to house an x ray spectrometer. This work is part of the design and construction of the balloon experiment, GRATIS, which will perform the first arcminute imaging of cosmic sources in the 30 to 200 keV energy band. Observations conducted with GRATIS are expected to provide data relevant to several key problems in high energy astrophysics including the physical processes responsible for the high energy tail observed in the soft gamma-ray spectra of clusters of galaxies and the origin of both the diffuse and point source components of the gamma-ray emission from the Galactic Center. This report discusses the scientific motivations for this experiment, presents several aspects of the design and construction of the hardware components, gives an overview of the stabilized platform, and demonstrates the expected performance and sensitivity.

  3. SN X-ray Progenitor?

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Identifying stars that explode, right before they explode, is a tricky proposition since the end of starlife comes swiftly: in thermonuclear deflagrations, in nuclear exhaustion, or maybe in a rapid swirling merger of two dead stellar cores. On the right in the image above is an image of the galaxy NGC 1404 taken by the UV/optical Telescope (UVOT) on the Swift observatory. The circle surrounds SN 2007on, a supernova of Type Ia produced by the explosion of a white dwarf star in a binary system. These types of supernovae are important since they are believed to be 'standard candles', events which have the same intrinsic brightness which can serve as an important yardstick to measure cosmic distances. On the left is an image of the same galaxy taken by the Chandra X-ray observatory four years before the supernova. Conspicuous in the SN source circle is a bright source in the Chandra image, believed to be emission from a compact object+normal star companion: a similar system to the supposed precursor of SN 2007on. If true this would be the first time a Type Ia supernova precursor has ever been seen. But astronomers are still debating whether the Chandra source really is the precursor or not; it seems there's a slight but significant difference in the location of the Chandra source and the supernova. Stay tuned for more developments.

  4. X-ray satellite (Rosat)

    NASA Technical Reports Server (NTRS)

    1986-01-01

    An overview of the current status of the ROSAT X-Ray satellite project is given. Areas discussed include an overview of problem areas, systems and mechanical subsystems, the electrical subsystem, power supply, data processing and transmission, the wide field camera, ground support equipment and the production scheduling. It is shown that the project is proceeding according to schedule, including the hardware production and costs. However, it is stated that estimated additional costs will exceed the plan. The previous schedule for production of the flight model will no longer be met. A modified milestone plan has been worked out with Dornier Systems. The current working schedule calls for a launch data of December 21, 1987; however, this does not take into account a 4-week buffer prior to transporting the flight model to the launch site. As of the date of this report, milestone M5 has been met. Previous problems with the gold vapor deposition on the flight model mirror due to contamination have been eliminated.

  5. Foil X-ray Mirrors

    NASA Astrophysics Data System (ADS)

    Serlemitsos, Peter J.; Soong, Yang

    1996-09-01

    Nested thin foil reflectors have made possible light weight, inexpensive and fast grazing incidence X-ray mirrors for astronomical spectroscopy over a broad band. These mirrors were developed at Goddard for the US Shuttle program and were flown on NASA's shuttleborne Astro-l mission in December 1990. Presently, the Japan/US collaborative spectroscopic mission ASCA, nearing its third year of successful operation in earth orbit, carries, four such mirrors, weighing less than 40 kg and giving total effective areas of ˜ 1200 and 420 cm2 at l and 8 keV respectively. The ˜ 420 kg observatory is the best possible example of how conical foil mirrors opened areas of research that could not have been otherwise addressed with available resources. In this paper, we will briefly review the development and performance of our first generation foil mirrors. We will also describe progress toward improving their imaging capability to prime them for use in future instruments. Such a goal is highly desirable, if not necessary for this mirror technology to remain competitive for future applications.

  6. X ray lithography in Japan

    NASA Astrophysics Data System (ADS)

    Clemens, James T.; Hill, Robert W.; Cerrina, Franco; Fuller, Gene E.; Pease, R. F.

    1991-10-01

    Integrated circuits (semiconductors) are the key components of modern computers, communication systems, consumer electronics, and the new generations of smart machines and instruments. Japan's strong position and growing influence in the manufacture of semiconductors and systems based on them is well known and well documented. Microlithography is one the most critical elements of the semiconductor manufacturing process because it determines the minimum feature size and the functional capabilities of the semiconductor. Because it is used many times in the manufacturing sequence, the quality of the microlithography process (i.e., number of defects, control for feature size, etc.) is critical in determining the yield and cost of semiconductors and hence the competitiveness of the electronics industry. At present all volume semiconductor manufacturing is done with optical UV (ultraviolet) projection lithography, twenty-year-old photographic technology which has been and is still evolving. There are many issues that limit the technical capability and cost-effectiveness of UV lithography, and thus, alternate lithographic techniques are continuously being researched and developed. X-ray lithography, which was invented in the early 1970's, holds the promise of providing higher yields in manufacturing semiconductors by virtue of enhanced process latitude, process robustness, and resolution.

  7. Hard X-ray delays

    NASA Technical Reports Server (NTRS)

    Schwartz, Richard A.

    1986-01-01

    High time resolution hard X-ray rates with good counting statistics over 5 energy intervals were obtained using a large area balloon-borne scintillation detector during the 27 June 1980 solar flare. The impulsive phase of the flare was comprised of a series of major bursts of several to several tens of seconds long. Superimposed on these longer bursts are numerous smaller approximately 0.5 to 1.0 second spikes. The time profiles for different energies were cross-correlated for the major bursts. The rapid burst decay rates and the simultaneous peaks below 120 keV both indicate a rapid electron energy loss process. Thus, the flux profiles reflect the electron acceleration/injection process. The fast rate data was obtained by a burst memory in 8 and 32 msec resolution over the entire main impulsive phase. These rates will be cross-correlated to look for short time delays and to find rapid fluctuations. However, a cursory examination shows that almost all fluctuations, down to the 5% level, were resolved with 256 msec bins.

  8. Wide field x-ray telescopes: Detecting x-ray transients/afterglows related to GRBs

    SciTech Connect

    Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul

    1998-05-16

    The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited fields of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70's but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster-eye type are presented and discussed. The optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed.

  9. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    DOEpatents

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

  10. A room-temperature X-ray-induced photochromic material for X-ray detection.

    PubMed

    Wang, Ming-Sheng; Yang, Chen; Wang, Guan-E; Xu, Gang; Lv, Xiang-Ying; Xu, Zhong-Ning; Lin, Rong-Guang; Cai, Li-Zhen; Guo, Guo-Cong

    2012-04-02

    A color change: X-ray-induced photochromic species are rare and can be used for detection of X-rays. A highly robust X-ray-sensitive material with the discrete structure of a metal-organic complex has been found to show both soft and hard X-ray-induced photochromism at room temperature. A new ligand-to-ligand electron-transfer mechanism was proposed to elucidate this photochromic phenomenon.

  11. The future in X-ray surveys

    NASA Astrophysics Data System (ADS)

    Hasinger, Günther

    2015-08-01

    I will chair this "Way Forward" discusson about the future in X-ray Surveys at the Focus Meeting #6Cosmological X-ray Surveys: probing the Hot and Energetic Cosmos. Participants will be R. Gilli,G. Pratt, G. Fabbiano, X. Barcons, T. Ohashi, F. Harrison.

  12. VETA-1 x ray detection system

    NASA Technical Reports Server (NTRS)

    Podgorski, W. A.; Flanagan, Kathy A.; Freeman, Mark D.; Goddard, R. G.; Kellogg, Edwin M.; Norton, T. J.; Ouellette, J. P.; Roy, A. G.; Schwartz, Daniel A.

    1992-01-01

    The alignment and X-ray imaging performance of the Advanced X-ray Astrophysics Facility (AXAF) Verification Engineering Test Article-I (VETA-I) was measured by the VETA-I X-Ray Detection System (VXDS). The VXDS was based on the X-ray detection system utilized in the AXAF Technology Mirror Assembly (TMA) program, upgraded to meet the more stringent requirements of the VETA-I test program. The VXDS includes two types of X-ray detectors: (1) a High Resolution Imager (HRI) which provides X-ray imaging capabilities, and (2) sealed and flow proportional counters which, in conjunction with apertures of various types and precision translation stages, provide the most accurate measurement of VETA-I performance. Herein we give an overview of the VXDS hardware including X-ray detectors, translation stages, apertures, proportional counters and flow counter gas supply system and associated electronics. We also describe the installation of the VXDS into the Marshall Space Flight Center (MSFC) X-Ray Calibration Facility (XRCF). We discuss in detail the design and performance of those elements of the VXDS which have not been discussed elsewhere; translation systems, flow counter gas supply system, apertures and thermal monitoring system.

  13. X-rays from intermediate mass stars

    NASA Astrophysics Data System (ADS)

    Robrade, Jan

    I will review the X-ray properties of intermediate mass stars and discuss possible X-ray generating mechanisms. Main-sequence stars of spectral type mid B to mid A neither drive sufficiently strong winds to produce shock generated X-rays, nor possess an outer convection zone to generate dynamo driven magnetic activity and coronae. Consequently they should be virtually X-ray dark and occasionally detected X-ray emission was usually attributed to undetected low-mass companions. However, in magnetic intermediate mass stars, the Ap/Bp stars, a different X-ray production mechanism may operate. It is termed the magnetically channeled wind-shock model, where the stellar wind from both hemispheres is channelled towards the equatorial plane, collides and forms a rigidly rotating disk around the star. The strong shocks of the nearly head-on wind collision as well as the existence of magnetically confined plasma in a dynamic circumstellar disk can lead to diverse X-ray phenomena. In this sense Ap/Bp stars bridge the 'classical' X-ray regimes of cool and hot stars.

  14. High resolution X-ray scattering measurements

    NASA Technical Reports Server (NTRS)

    Zombeck, M. V.; Braeuninger, H.; Ondrusch, A.; Predehl, P.

    1982-01-01

    The results of high angular resolution grazing incidence scattering measurements of highly polished, coated optical flats in the X-ray spectral range of 1.5 to 6.4 keV are reported. The interpretation of these results in terms of surface microtopography is presented and the implications for grazing incidence X-ray imaging are discussed.

  15. Phased Contrast X-Ray Imaging

    ScienceCinema

    Erin Miller

    2016-07-12

    The Pacific Northwest National Laboratory is developing a range of technologies to broaden the field of explosives detection. Phased contrast X-ray imaging, which uses silicon gratings to detect distortions in the X-ray wave front, may be applicable to mail or luggage scanning for explosives; it can also be used in detecting other contraband, small-parts inspection, or materials characterization.

  16. Coccidioidomycosis - chest x-ray (image)

    MedlinePlus

    This chest x-ray shows the affects of a fungal infection, coccidioidomycosis. In the middle of the left lung (seen on the ... defined borders. Other diseases that may explain these x-ray findings include lung abscesses, chronic pulmonary tuberculosis, chronic ...

  17. Adenocarcinoma - chest x-ray (image)

    MedlinePlus

    This chest x-ray shows adenocarcinoma of the lung. There is a rounded light spot in the right upper lung (left side ... density. Diseases that may cause this type of x-ray result would be tuberculous or fungal granuloma, and ...

  18. X-Ray Detection Visits the Classroom

    ERIC Educational Resources Information Center

    Peralta, Luis; Farinha, Ana; Pinto, Ana

    2008-01-01

    Film has been used to detect x-rays since the early days of their discovery by Rontgen. Although nowadays superseded by other techniques, film still provides a cheap means of x-ray detection, making it attractive in high-school or undergraduate university courses. If some sort of quantitative result is required, the film's optical absorbance or…

  19. Accelerator-driven X-ray Sources

    SciTech Connect

    Nguyen, Dinh Cong

    2015-11-09

    After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

  20. X-ray dynamical diffraction Fraunhofer holography.

    PubMed

    Balyan, Minas

    2013-09-01

    An X-ray dynamical diffraction Fraunhofer holographic scheme is proposed. Theoretically it is shown that the reconstruction of the object image by visible light is possible. The spatial and temporal coherence requirements of the incident X-ray beam are considered. As an example, the hologram recording as well as the reconstruction by visible light of an absolutely absorbing wire are discussed.

  1. X-ray spectroscopy of magnetic CVs

    NASA Astrophysics Data System (ADS)

    Matt, Giorgio

    I discuss two topics in X-ray spectroscopy of magnetic CVs: reflection from the white dwarf surface, and opacity effects in the post shock plasma. I also briefly mention future observational perspectives, with particular emphasis on the Constellation X-ray mission.

  2. Course Manual for X-Ray Applications.

    ERIC Educational Resources Information Center

    Food and Drug Administration (DHEW), Rockville, MD. Bureau of Radiological Health.

    This publication is the third of three sequential course manuals for instructors in x-ray science and engineering. This course manual has been tested by introducing it into the Oregon State University curriculum. The publication is prepared for the purpose of improving the qualifications of x-ray users and to reduce the ionizing radiation exposure…

  3. X-ray phase scanning setup for non-destructive testing using Talbot-Lau interferometer

    NASA Astrophysics Data System (ADS)

    Bachche, S.; Nonoguchi, M.; Kato, K.; Kageyama, M.; Koike, T.; Kuribayashi, M.; Momose, A.

    2016-09-01

    X-ray grating interferometry has a great potential for X-ray phase imaging over conventional X-ray absorption imaging which does not provide significant contrast for weakly absorbing objects and soft biological tissues. X-ray Talbot and Talbot-Lau interferometers which are composed of transmission gratings and measure the differential X-ray phase shifts have gained popularity because they operate with polychromatic beams. In X-ray radiography, especially for nondestructive testing in industrial applications, the feasibility of continuous sample scanning is not yet completely revealed. A scanning setup is frequently advantageous when compared to a direct 2D static image acquisition in terms of field of view, exposure time, illuminating radiation, etc. This paper demonstrates an efficient scanning setup for grating-based Xray phase imaging using laboratory-based X-ray source. An apparatus consisting of an X-ray source that emits X-rays vertically, optical gratings and a photon-counting detector was used with which continuously moving objects across the field of view as that of conveyor belt system can be imaged. The imaging performance of phase scanner was tested by scanning a long continuous moving sample at a speed of 5 mm/s and absorption, differential-phase and visibility images were generated by processing non-uniform moire movie with our specially designed phase measurement algorithm. A brief discussion on the feasibility of phase scanner with scanning setup approach including X-ray phase imaging performance is reported. The successful results suggest a breakthrough for scanning objects those are moving continuously on conveyor belt system non-destructively using the scheme of X-ray phase imaging.

  4. The Advanced X-Ray Astrophysics Facility. Observing the Universe in X-Rays

    NASA Technical Reports Server (NTRS)

    Neal, V.

    1984-01-01

    An overview of the Advanced X ray Astronophysics Facility (AXAF) program is presented. Beginning with a brief introduction to X ray astrophysics, the AXAF observatory is described including the onboard instrumentation and system capabilities. Possible X ray sources suitable for AXAF observation are identified and defined.

  5. X-Rays from Green Pea Analogs

    NASA Astrophysics Data System (ADS)

    Brorby, Matthew

    2014-09-01

    X-rays may have contributed to the heating and reionization of the IGM in the early universe. High mass X-ray binaries (HMXB) within small, low-metallicity galaxies are expected to be the main source of X-rays at this time. Since studying these high-redshift galaxies is currently impossible, we turn to local analogs that have the same properties the galaxies in the early are expected to have. A number of recent studies have shown an enhanced number of HMXBs in nearby low metallicity galaxies. We propose to observe a sample of metal-deficient luminous compact galaxies (LCG) in order to determine if the X-ray luminosity is enhanced relative to SFR, thereby providing further evidence to the importance of X-rays in the early universe.

  6. X-ray diffraction: instrumentation and applications.

    PubMed

    Bunaciu, Andrei A; Udriştioiu, Elena Gabriela; Aboul-Enein, Hassan Y

    2015-01-01

    X-ray diffraction (XRD) is a powerful nondestructive technique for characterizing crystalline materials. It provides information on structures, phases, preferred crystal orientations (texture), and other structural parameters, such as average grain size, crystallinity, strain, and crystal defects. X-ray diffraction peaks are produced by constructive interference of a monochromatic beam of X-rays scattered at specific angles from each set of lattice planes in a sample. The peak intensities are determined by the distribution of atoms within the lattice. Consequently, the X-ray diffraction pattern is the fingerprint of periodic atomic arrangements in a given material. This review summarizes the scientific trends associated with the rapid development of the technique of X-ray diffraction over the past five years pertaining to the fields of pharmaceuticals, forensic science, geological applications, microelectronics, and glass manufacturing, as well as in corrosion analysis.

  7. Apollo 15 X-ray fluorescence experiment

    NASA Technical Reports Server (NTRS)

    Adler, I.; Trombka, J.; Gerard, J.; Schmadebeck, R.; Lowman, P.; Blodgett, H.; Yin, L.; Eller, E.; Lamothe, R.; Gorenstein, P.

    1971-01-01

    The X-ray fluorescence spectrometer, carried in the SIM bay of the command service module was employed principally for compositional mapping of the lunar surface while in lunar orbit, and secondarily, for X-ray astronomical observations during the trans-earth coast. The lunar surface measurements involved observations of the intensity and characteristics energy distribution of the secondary or fluorescent X-rays produced by the interaction of solar X-rays with the lunar surface. The astronomical observations consisted of relatively long periods of measurements of X-rays from pre-selected galactic sources such as Cyg-X-1 and Sco X-1 as well as from the galactic poles.

  8. Perspectives of medical X-ray imaging

    NASA Astrophysics Data System (ADS)

    Freudenberger, J.; Hell, E.; Knüpfer, W.

    2001-06-01

    While X-ray image intensifiers (XII), storage phosphor screens and film-screen systems are still the work horses of medical imaging, large flat panel solid state detectors using either scintillators and amorphous silicon photo diode arrays (FD-Si), or direct X-ray conversion in amorphous selenium are reaching maturity. The main advantage with respect to image quality and low patient dose of the XII and FD-Si systems is caused by the rise of the Detector Quantum Efficiency originating from the application of thick needle-structured phosphor X-ray absorbers. With the detectors getting closer to an optimal state, further progress in medical X-ray imaging requires an improvement of the usable source characteristics. The development of clinical monochromatic X-ray sources of high power would not only allow an improved contrast-to-dose ratio by allowing smaller average photon energies in applications but would also lead to new imaging techniques.

  9. Solar x ray astronomy rocket program

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The dynamics were studied of the solar corona through the imaging of large scale coronal structures with AS&E High Resolution Soft X ray Imaging Solar Sounding Rocket Payload. The proposal for this program outlined a plan of research based on the construction of a high sensitivity X ray telescope from the optical and electronic components of the previous flight of this payload (36.038CS). Specifically, the X ray sensitive CCD camera was to be placed in the prime focus of the grazing incidence X ray mirror. The improved quantum efficiency of the CCD detector (over the film which had previously been used) allows quantitative measurements of temperature and emission measure in regions of low x ray emission such as helmet streamers beyond 1.2 solar radii or coronal holes. Furthermore, the improved sensitivity of the CCD allows short exposures of bright objects to study unexplored temporal regimes of active region loop evolution.

  10. Imaging properties and its improvements of scanning/imaging x-ray microscope

    SciTech Connect

    Takeuchi, Akihisa Uesugi, Kentaro; Suzuki, Yoshio

    2016-01-28

    A scanning / imaging X-ray microscope (SIXM) system has been developed at SPring-8. The SIXM consists of a scanning X-ray microscope with a one-dimensional (1D) X-ray focusing device and an imaging (full-field) X-ray microscope with a 1D X-ray objective. The motivation of the SIXM system is to realize a quantitative and highly-sensitive multimodal 3D X-ray tomography by taking advantages of both the scanning X-ray microscope using multi-pixel detector and the imaging X-ray microscope. Data acquisition process of a 2D image is completely different between in the horizontal direction and in the vertical direction; a 1D signal is obtained with the linear-scanning while the other dimensional signal is obtained with the imaging optics. Such condition have caused a serious problem on the imaging properties that the imaging quality in the vertical direction has been much worse than that in the horizontal direction. In this paper, two approaches to solve this problem will be presented. One is introducing a Fourier transform method for phase retrieval from one phase derivative image, and the other to develop and employ a 1D diffuser to produce an asymmetrical coherent illumination.

  11. A model of an X-ray-illuminated accretion disk and corona

    NASA Technical Reports Server (NTRS)

    Raymond, John C.

    1993-01-01

    The X-ray-illuminated surface of the accretion disk in a low-mass X-ray Binary (LMXRB) and the X-ray-heated corona above the disk produce optical, UV, and soft X-ray emission lines. This paper presents 1D models of the emission line spectra and the vertical temperature and density structures at different radii. The models include a detailed treatment of the important atomic processes and an escape probability treatment of radiative transfer. Soker and Raymond (1993) use the density structure predicted by these models for a 2D Monte Carlo simulation of the photon scattering in the accretion disk corona (ADC) to examine the effects of the ADC on the angular distribution of X-rays and the flux of X-rays incident on the outer disk. This paper concentrates on the emission line fluxes for various elemental abundances and disk parameters. The UV lines of the classic LMXRBs are consistent with the model predictions. Some CNO processing is necessary to account for the nitrogen and helium abundances in Sco X-1 and other LMXRBs. Comparison of the models with observed spectra also points to a soft X-ray component with luminosity comparable to the hard X-rays. The models predict a substantial luminosity in the group of highly ionized iron lines near 100 A.

  12. Tissue Visualization Using X-Ray Dark-Field Imaging towards Pathological Goal

    NASA Astrophysics Data System (ADS)

    Ando, Masami; Chikaura, Yoshinori; Endo, Tokiko; Gupta, Rajiv; Huo, Qingkai; Hyodo, Kazuyuki; Ichihara, Shu; Mori, Kensaku; Nakao, Yuki; Ohura, Norihiko; Sunaguchi, Naoki; Sugiyama, Hiroshi; Suzuki, Yoshifumi; Wu, Yanlin; Yuasa, Tetsuya; Xiaowei, Zhang

    2013-03-01

    In XDFI (x-ray dark-field imaging) LAA (Laue-case angle analyzer) simultaneously provides two x-ray images; one corresponds to a FD forward diffracted beam and a separate D diffracted beam. When this is applied to biomedical specimens x-ray images are very high contrast and very high spatial resolution. We constructed XDFI system at the vertical wiggler beamline BL-14C in KEK Photon Factory and performed imaging experiment of breast tissues and an excised human femoral artery. In this paper, we discuss a tissue visualization and pathological goal using 2D, 3D-CT and 2.5D image (tomosynthesis) with XDFI.

  13. Flat-panel imaging system for fluoroscopy applications

    NASA Astrophysics Data System (ADS)

    Colbeth, Richard E.; Allen, Maxwell J.; Day, Derek J.; Gilblom, David L.; Harris, Richard A.; Job, Isaias D.; Klausmeier-Brown, Martin E.; Pavkovich, John M.; Seppi, Edward J.; Shapiro, Edward G.; Wright, Michael D.; Yu, Jiann M.

    1998-07-01

    This paper describes a multi-mode, digital imager for real- time x-ray applications. The imager has three modes of operation: low dose fluoroscopy, zoom fluoroscopy, and high resolution radiography. These modes trade-off resolution or field-of-view for frame rate and additionally optimize the sensitivity of the imager to match the x-ray dose used in each mode. This large area sensing technology has a form factor similar to that of a film cassette, no geometric image distortion, no sensitivity to magnetic fields, a very large dynamic range which eliminates repeat shots due to over or under exposure, 12 bit digital output and the ability to switch between operating modes in real-time. The imager, which consists of three modules: the Receptor, the Power Supply and the Command Processor, is intended as a component in a larger imaging system. Preliminary characterization of the prototype imager in fluoroscopic mode at entrance exposure rates down to 2.5 (mu) R/frame, indicates that the DQE(f), MTF and low contrast resolution are comparable to that obtained with an image intensifier tube (IIT) coupled to a video camera.

  14. Coherent X-ray radiation excited by a diverging relativistic electron beam in a single crystal

    SciTech Connect

    Blazhevich, S. V. Noskov, A. V.

    2015-05-15

    We develop a dynamic theory of coherent X-rays generated in a single-crystal wafer by a diverging relativistic electron beam. The dependence of the spectral-angular density of coherent X-ray radiation on the angle of divergence is analyzed for the case when the angular spread can be described by the 2D Gaussian distribution. The theory constructed here makes it possible to analyze coherent radiation for an arbitrary angular distribution of electrons in the beam as well.

  15. Coherent X-ray radiation excited by a diverging relativistic electron beam in a single crystal

    NASA Astrophysics Data System (ADS)

    Blazhevich, S. V.; Noskov, A. V.

    2015-05-01

    We develop a dynamic theory of coherent X-rays generated in a single-crystal wafer by a diverging relativistic electron beam. The dependence of the spectral-angular density of coherent X-ray radiation on the angle of divergence is analyzed for the case when the angular spread can be described by the 2D Gaussian distribution. The theory constructed here makes it possible to analyze coherent radiation for an arbitrary angular distribution of electrons in the beam as well.

  16. Detection of x ray sources in PROS

    NASA Technical Reports Server (NTRS)

    Deponte, J.; Primini, F. A.

    1992-01-01

    The problem of detecting discrete sources in x-ray images has much in common with the problem of automatic source detection at other wavelengths. In all cases, one searches for positive brightness enhancements exceeding a certain threshold, which appear consistent with what one expects for a point source, in the presence of a (possibly) spatially variable background. Multidimensional point spread functions (e.g., dependent on detector position and photon energy) are also common. At the same time, the problem in x-ray astronomy has some unique aspects. For example, for typical x-ray exposures in current or recent observatories, the number of available pixels far exceeds the number of actual x-ray events, so Poisson, rather than Gaussian statistics apply. Further, extended cosmic x-ray sources are common, and one often desires to detect point sources in the vicinity or even within bright, diffuse x-ray emission. Finally, support structures in x-ray detectors often cast sharp shadows in x-ray images making it necessary to detect sources in a region of rapidly varying exposure. We have developed a source detection package within the IRAF/PROS environment which attempts to deal with some of the problems of x-ray source detection. We have patterned our package after the successful Einstein Observatory x-ray source detection programs. However, we have attempted to improve the flexibility and accessibility of the functions and to provide a graphical front-end for the user. Our philosophy has been to use standard IRAF tasks whenever possible for image manipulation and to separate general functions from mission-specific ones. We will report on the current status of the package and discuss future developments, including simulation tasks, to allow the user to assess detection efficiency and source significance, tasks to determine source intensity, and alternative detection algorithms.

  17. Quantitative Measurements of X-ray Intensity

    SciTech Connect

    Haugh, M. J., Schneider, M.

    2011-09-01

    This chapter describes the characterization of several X-ray sources and their use in calibrating different types of X-ray cameras at National Security Technologies, LLC (NSTec). The cameras are employed in experimental plasma studies at Lawrence Livermore National Laboratory (LLNL), including the National Ignition Facility (NIF). The sources provide X-rays in the energy range from several hundred eV to 110 keV. The key to this effort is measuring the X-ray beam intensity accurately and traceable to international standards. This is accomplished using photodiodes of several types that are calibrated using radioactive sources and a synchrotron source using methods and materials that are traceable to the U.S. National Institute of Standards and Technology (NIST). The accreditation procedures are described. The chapter begins with an introduction to the fundamental concepts of X-ray physics. The types of X-ray sources that are used for device calibration are described. The next section describes the photodiode types that are used for measuring X-ray intensity: power measuring photodiodes, energy dispersive photodiodes, and cameras comprising photodiodes as pixel elements. Following their description, the methods used to calibrate the primary detectors, the power measuring photodiodes and the energy dispersive photodiodes, as well as the method used to get traceability to international standards are described. The X-ray source beams can then be measured using the primary detectors. The final section then describes the use of the calibrated X-ray beams to calibrate X-ray cameras. Many of the references are web sites that provide databases, explanations of the data and how it was generated, and data calculations for specific cases. Several general reference books related to the major topics are included. Papers expanding some subjects are cited.

  18. Explosives detection using photoneutrons produced by X-rays

    NASA Astrophysics Data System (ADS)

    Yang, Yigang; Li, Yuanjing; Wang, Haidong; Li, Tiezhu; Wu, Bin

    2007-08-01

    The detection of explosives has become a critical issue after recent terrorist attacks. This paper describes research on explosives detection using photoneutrons from a photoneutron convertor that consists of 20 kg heavy water in an aluminum container whose shape was optimized to most effectively convert X-rays to photoneutrons. The X-rays were produced by a 9 MeV electron accelerator with an average electron current of 100 μA, resulted in a photoneutron yield of >10 11 n/s. Monte-Carlo simulations show that the radiation field is composed of X-ray pulses, fast neutron pulses and thermal neutrons. Both the X-ray and fast neutron pulses are 5 μs wide with a 300 Hz repetition frequency. The thermal neutron flux, which is higher than 10 4 n/cm 2/s, is essentially time invariant. A time shielding circuit was developed for the spectrometry system to halt the sampling process during the intense X-ray pulses. Paraffin, boron carbide and lead were used to protect the detector from interference from the X-rays, fast neutrons, thermal neutrons and background γ-rays coming from the system materials induced by photoneutrons. 5″×5″ NaI (Tl) scintillators were chosen as the detectors to detect the photoneutrons induced γ-rays from the inspected explosive simulant. Nitrogen (6.01 cps) 10.828 MeV γ-rays were detected with one detector from a 50 kg carbamide block placed 60 cm in front of the detector. A collimator was used to reduce the number of background 10.828 MeV γ-rays coming from the nitrogen in the air to improve the signal to background ratio from 0.136 to 1.81. A detector array of seven 5″×5″ NaI (Tl) detectors was used to measure the 2-D distributions of N and H in the sample. The combination of photoneutron analysis and X-ray imaging shows promise for enhancing explosives detection capabilities.

  19. Compact pnCCD-based X-ray camera with high spatial and energy resolution: a color X-ray camera.

    PubMed

    Scharf, O; Ihle, S; Ordavo, I; Arkadiev, V; Bjeoumikhov, A; Bjeoumikhova, S; Buzanich, G; Gubzhokov, R; Günther, A; Hartmann, R; Kühbacher, M; Lang, M; Langhoff, N; Liebel, A; Radtke, M; Reinholz, U; Riesemeier, H; Soltau, H; Strüder, L; Thünemann, A F; Wedell, R

    2011-04-01

    For many applications there is a requirement for nondestructive analytical investigation of the elemental distribution in a sample. With the improvement of X-ray optics and spectroscopic X-ray imagers, full field X-ray fluorescence (FF-XRF) methods are feasible. A new device for high-resolution X-ray imaging, an energy and spatial resolving X-ray camera, is presented. The basic idea behind this so-called "color X-ray camera" (CXC) is to combine an energy dispersive array detector for X-rays, in this case a pnCCD, with polycapillary optics. Imaging is achieved using multiframe recording of the energy and the point of impact of single photons. The camera was tested using a laboratory 30 μm microfocus X-ray tube and synchrotron radiation from BESSY II at the BAMline facility. These experiments demonstrate the suitability of the camera for X-ray fluorescence analytics. The camera simultaneously records 69,696 spectra with an energy resolution of 152 eV for manganese K(α) with a spatial resolution of 50 μm over an imaging area of 12.7 × 12.7 mm(2). It is sensitive to photons in the energy region between 3 and 40 keV, limited by a 50 μm beryllium window, and the sensitive thickness of 450 μm of the chip. Online preview of the sample is possible as the software updates the sums of the counts for certain energy channel ranges during the measurement and displays 2-D false-color maps as well as spectra of selected regions. The complete data cube of 264 × 264 spectra is saved for further qualitative and quantitative processing.

  20. Automatic filter placement device for region of interest (ROI) fluoroscopy.

    PubMed

    Kezerashvili, M; Rudin, S; Bednarek, D

    1997-01-01

    In Region of Interest (ROI) Fluoroscopy, an ROI filter is inserted into the x-ray beam in order to decrease the patient exposure in the peripheral part of the field of view. A filter placement device has been designed and constructed for the practical implementation of ROI fluoroscopy. When unmodified spot films are required during fluoroscopic procedures, an electronic signal from the high voltage generator triggers the filter placement device to remove the ROI filter automatically from the field of view and to reinsert it after the conclusion of the spot film exposure. The filter placement device is easily fastened to existing tracks on undertable tube fluoroscopic collimators. A transmission ionization chamber may be placed above the filter assembly so that radiation to the patient may be monitored during ROI fluoroscopic procedures. The mechanical design is compact and involves only one miniature gear-head motor. The filter placement device allows rapid filter positioning in 200 ms so that there is no interference with spot filming. A simple electronic circuit provides 8 volts for rapid motion of the filter support arm and 4 volts for holding the filter in place. This device demonstrates that ROI fluoroscopy with its associated large reduction in patient integral dose can be practically implemented in standard fluoroscopic equipment.

  1. Novel System for Real-Time Integration of 3-D Echocardiography and Fluoroscopy for Image-Guided Cardiac Interventions: Preclinical Validation and Clinical Feasibility Evaluation

    PubMed Central

    Housden, R. James; Ma, Yingliang; Rajani, Ronak; Gao, Gang; Nijhof, Niels; Cathier, Pascal; Bullens, Roland; Gijsbers, Geert; Parish, Victoria; Kapetanakis, Stamatis; Hancock, Jane; Rinaldi, C. Aldo; Cooklin, Michael; Gill, Jaswinder; Thomas, Martyn; O'neill, Mark D.; Razavi, Reza; Rhode, Kawal S.

    2014-01-01

    Real-time imaging is required to guide minimally invasive catheter-based cardiac interventions. While transesophageal echocardiography allows for high-quality visualization of cardiac anatomy, X-ray fluoroscopy provides excellent visualization of devices. We have developed a novel image fusion system that allows real-time integration of 3-D echocardiography and the X-ray fluoroscopy. The system was validated in the following two stages: 1) preclinical to determine function and validate accuracy; and 2) in the clinical setting to assess clinical workflow feasibility and determine overall system accuracy. In the preclinical phase, the system was assessed using both phantom and porcine experimental studies. Median 2-D projection errors of 4.5 and 3.3 mm were found for the phantom and porcine studies, respectively. The clinical phase focused on extending the use of the system to interventions in patients undergoing either atrial fibrillation catheter ablation (CA) or transcatheter aortic valve implantation (TAVI). Eleven patients were studied with nine in the CA group and two in the TAVI group. Successful real-time view synchronization was achieved in all cases with a calculated median distance error of 2.2 mm in the CA group and 3.4 mm in the TAVI group. A standard clinical workflow was established using the image fusion system. These pilot data confirm the technical feasibility of accurate real-time echo-fluoroscopic image overlay in clinical practice, which may be a useful adjunct for real-time guidance during interventional cardiac procedures. PMID:27170872

  2. Intraoperative positioning of mobile C-arms using artificial fluoroscopy

    NASA Astrophysics Data System (ADS)

    Dressel, Philipp; Wang, Lejing; Kutter, Oliver; Traub, Joerg; Heining, Sandro-Michael; Navab, Nassir

    2010-02-01

    In trauma and orthopedic surgery, imaging through X-ray fluoroscopy with C-arms is ubiquitous. This leads to an increase in ionizing radiation applied to patient and clinical staff. Placing these devices in the desired position to visualize a region of interest is a challenging task, requiring both skill of the operator and numerous X-rays for guidance. We propose an extension to C-arms for which position data is available that provides the surgeon with so called artificial fluoroscopy. This is achieved by computing digitally reconstructed radiographs (DRRs) from pre- or intraoperative CT data. The approach is based on C-arm motion estimation, for which we employ a Camera Augmented Mobile C-arm (CAMC) system, and a rigid registration of the patient to the CT data. Using this information we are able to generate DRRs and simulate fluoroscopic images. For positioning tasks, this system appears almost exactly like conventional fluoroscopy, however simulating the images from the CT data in realtime as the C-arm is moved without the application of ionizing radiation. Furthermore, preoperative planning can be done on the CT data and then visualized during positioning, e.g. defining drilling axes for pedicle approach techniques. Since our method does not require external tracking it is suitable for deployment in clinical environments and day-to-day routine. An experiment with six drillings into a lumbar spine phantom showed reproducible accuracy in positioning the C-arm, ranging from 1.1 mm to 4.1 mm deviation of marker points on the phantom compared in real and virtual images.

  3. Recent X-ray Variability of Eta Car Approaching The X-ray Eclipse

    NASA Technical Reports Server (NTRS)

    Corcoran, M.; Swank, J. H.; Ishibashi, K.; Gull, T.; Humphreys, R.; Damineli, A.; Walborn, N.; Hillier, D. J.; Davidson, K.; White, S. M.

    2002-01-01

    We discuss recent X-ray spectral variability of the supermassive star Eta Car in the interval since the last X-ray eclipse in 1998. We concentrate on the interval just prior to the next X-ray eclipse which is expected to occur in June 2003. We compare the X-ray behavior during the 2001-2003 cycle with the previous cycle (1996-1998) and note similarities and differences in the temporal X-ray behavior. We also compare a recent X-ray observation of Eta Car obtained with the Chandra high energy transmission grating in October 2002 with an earlier observation from Nov 2002, and interpret these results in terms of the proposed colliding wind binary model for the star. In addition we discuss planned observations for the upcoming X-ray eclipse.

  4. X-Ray Background from Early Binaries

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    What impact did X-rays from the first binary star systems have on the universe around them? A new study suggests this radiation may have played an important role during the reionization of our universe.Ionizing the UniverseDuring the period of reionization, the universe reverted from being neutral (as it was during recombination, the previous period)to once again being ionized plasma a state it has remained in since then. This transition, which occurred between 150 million and one billion years after the Big Bang (redshift of 6 z 20), was caused by the formation of the first objects energetic enough to reionize the universes neutral hydrogen.ROSAT image of the soft X-ray background throughout the universe. The different colors represent different energy bands: 0.25 keV (red), 0.75 keV (green), 1.5 keV (blue). [NASA/ROSAT Project]Understanding this time period in particular, determining what sources caused the reionization, and what the properties were of the gas strewn throughout the universe during this time is necessary for us to be able to correctly interpret cosmological observations.Conveniently, the universe has provided us with an interesting clue: the large-scale, diffuse X-ray background we observe all around us. What produced these X-rays, and what impact did this radiation have on the intergalactic medium long ago?The First BinariesA team of scientists led by Hao Xu (UC San Diego) has suggested that the very first generation of stars might be an important contributor to these X-rays.This hypothetical first generation, Population III stars, are thought to have formed before and during reionization from large clouds of gas containing virtually no metals. Studies suggest that a large fraction of Pop III stars formed in binaries and when those stars ended their lives as black holes, ensuing accretion from their companions could produceX-ray radiation.The evolution with redshift of the mean X-ray background intensities. Each curve represents a different

  5. Toward Adaptive X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Atkins, Carolyn; Button, Tim W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peer; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Kolodziejczak, Jeffrey J.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Rodriguez Sanmartin, Daniel; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

    2011-01-01

    Future x-ray observatories will require high-resolution (less than 1 inch) optics with very-large-aperture (greater than 25 square meter) areas. Even with the next generation of heavy-lift launch vehicles, launch-mass constraints and aperture-area requirements will limit the surface areal density of the grazing-incidence mirrors to about 1 kilogram per square meter or less. Achieving sub-arcsecond x-ray imaging with such lightweight mirrors will require excellent mirror surfaces, precise and stable alignment, and exceptional stiffness or deformation compensation. Attaining and maintaining alignment and figure control will likely involve adaptive (in-space adjustable) x-ray optics. In contrast with infrared and visible astronomy, adaptive optics for x-ray astronomy is in its infancy. In the middle of the past decade, two efforts began to advance technologies for adaptive x-ray telescopes: The Generation-X (Gen-X) concept studies in the United States, and the Smart X-ray Optics (SXO) Basic Technology project in the United Kingdom. This paper discusses relevant technological issues and summarizes progress toward adaptive x-ray telescopes.

  6. Toward active x-ray telescopes

    NASA Astrophysics Data System (ADS)

    O'Dell, Stephen L.; Atkins, Carolyn; Button, Timothy W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peter; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Kolodziejczak, Jeffery J.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Rodriguez Sanmartin, Daniel; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

    2011-09-01

    Future x-ray observatories will require high-resolution (< 1") optics with very-large-aperture (> 25 m2) areas. Even with the next generation of heavy-lift launch vehicles, launch-mass constraints and aperture-area requirements will limit the areal density of the grazing-incidence mirrors to about 1 kg/m2 or less. Achieving sub-arcsecond x-ray imaging with such lightweight mirrors will require excellent mirror surfaces, precise and stable alignment, and exceptional stiffness or deformation compensation. Attaining and maintaining alignment and figure control will likely involve active (in-space adjustable) x-ray optics. In contrast with infrared and visible astronomy, active optics for x-ray astronomy is in its infancy. In the middle of the past decade, two efforts began to advance technologies for adaptive x-ray telescopes: The Smart X-ray Optics (SXO) Basic Technology project in the United Kingdom (UK) and the Generation-X (Gen-X) concept studies in the United States (US). This paper discusses relevant technological issues and summarizes progress toward active x-ray telescopes.

  7. X-ray monitoring for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Pina, L.; Burrows, D.; Cash, W.; Cerna, D.; Gorenstein, P.; Hudec, R.; Inneman, A.; Jakubek, J.; Marsikova, V.; Sieger, L.; Tichy, V.

    2014-09-01

    This work addresses the issue of X-ray monitoring for astrophysical applications. The proposed wide-field optical system has not been used in space yet. The proposed novel approach is based on the use of 1D "Lobster eye" optics in combination with Timepix X-ray detector in the energy range 3 - 40 keV. The proposed project includes theoretical study and a functional sample of the Timepix X-ray detector with multifoil wide-field X-ray "Lobster eye" optics. Using optics to focus X-rays on a detector is the only solution in cases the intensity of impinging X-ray radiation is below the sensitivity of the detector, e.g. while monitoring astrophysical objects in space, or phenomena in the Earth's atmosphere. The optical system could be used in a student rocket experiment at University of Colorado. Ideal opportunity is to extend the CubeSat of Pennsylvania State University with the hard X-ray telescope demonstrator consisting of an optical module and Timepix detector.

  8. The X-ray binary, UW CMa

    NASA Technical Reports Server (NTRS)

    Heap, S. R.

    1982-01-01

    The UW CMa is a close, eclipsing binary composed of an O7f primary with a stron wind and a less luminous O-type companion. It was found that UW CMa a variable X-ray source, whose X-ray variations are in phase with its optical light curve. Since both components of the binary system are O stars, accretion by a compact object is ruled out as a mechanism for generating X-rays. The UW CMa represents a new class of X-ray binaries, in which X-rays result from the collision of a wind from one star with the surface or wind of the other star. It is hypothesised that the impact of a wind against a star generates a shock wave about 0.25 stellar radii above the stellar surface, and material behind the shock front, heated to bout 10 million degrees, radiates the X-ray apparent X-ray variability is due to its location between the two stars, where it undergoes eclipses. The high temperature region maintains an ionization cavity in the wind, as detected with IUE. The ionization cavity is the source of depletion of absorbing ions in the wind between the two stars.

  9. GEMS X-ray Polarimeter Performance Simulations

    NASA Technical Reports Server (NTRS)

    Baumgartner, Wayne H.; Strohmayer, Tod; Kallman, Tim; Black, J. Kevin; Hill, Joanne; Swank, Jean

    2012-01-01

    The Gravity and Extreme Magnetism Small explorer (GEMS) is an X-ray polarization telescope selected as a NASA small explorer satellite mission. The X-ray Polarimeter on GEMS uses a Time Projection Chamber gas proportional counter to measure the polarization of astrophysical X-rays in the 2-10 keV band by sensing the direction of the track of the primary photoelectron excited by the incident X-ray. We have simulated the expected sensitivity of the polarimeter to polarized X-rays. We use the simulation package Penelope to model the physics of the interaction of the initial photoelectron with the detector gas and to determine the distribution of charge deposited in the detector volume. We then model the charge diffusion in the detector,and produce simulated track images. Within the track reconstruction algorithm we apply cuts on the track shape and focus on the initial photoelectron direction in order to maximize the overall sensitivity of the instrument, using this technique we have predicted instrument modulation factors nu(sub 100) for 100% polarized X-rays ranging from 10% to over 60% across the 2-10 keV X-ray band. We also discuss the simulation program used to develop and model some of the algorithms used for triggering, and energy measurement of events in the polarimeter.

  10. Toward Active X-ray Telescopes II

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Aldroft, Thomas L.; Atkins, Carolyn; Button, Timothy W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peter; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Johnson-Wilke, Raegan L.; Kolodziejczak, Jeffery J.; Lillie, Charles F.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Sanmartin, Daniel Rodriguez; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan E.; Ulmer, Melville P.; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

    2012-01-01

    In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the sensitivity for detection of cosmic x-ray sources has improved by ten orders of magnitude. Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope. The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (greater than 1 m2) and finer angular resolution (less than 1.). Combined with the special requirements of grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically challenging.requiring precision fabrication, alignment, and assembly of large areas (greater than 100 m2) of lightweight (approximately 1 kg m2 areal density) mirrors. Achieving precise and stable alignment and figure control may entail active (in-space adjustable) x-ray optics. This paper discusses relevant programmatic and technological issues and summarizes progress toward active x-ray telescopes.

  11. Development of a universal medical X-ray imaging phantom prototype.

    PubMed

    Groenewald, Annemari; Groenewald, Willem A

    2016-11-01

    Diagnostic X-ray imaging depends on the maintenance of image quality that allows for proper diagnosis of medical conditions. Maintenance of image quality requires quality assurance programs on the various X-ray modalities, which consist of projection radiography (including mobile X-ray units), fluoroscopy, mammography, and computed tomography (CT) scanning. Currently a variety of modality-specific phantoms are used to perform quality assurance (QA) tests. These phantoms are not only expensive, but suitably trained personnel are needed to successfully use them and interpret the results. The question arose as to whether a single universal phantom could be designed and applied to all of the X-ray imaging modalities. A universal phantom would reduce initial procurement cost, possibly reduce the time spent on QA procedures and simplify training of staff on the single device. The aim of the study was to design and manufacture a prototype of a universal phantom, suitable for image quality assurance in general X-rays, fluoroscopy, mammography, and CT scanning. The universal phantom should be easy to use and would enable automatic data analysis, pass/fail reporting, and corrective action recommendation. In addition, a universal phantom would especially be of value in low-income countries where finances and human resources are limited. The design process included a thorough investigation of commercially available phantoms. Image quality parameters necessary for image quality assurance in the different X-ray imaging modalities were determined. Based on information obtained from the above-mentioned investigations, a prototype of a universal phantom was developed, keeping ease of use and reduced cost in mind. A variety of possible phantom housing and insert materials were investigated, considering physical properties, machinability, and cost. A three-dimensional computer model of the first phantom prototype was used to manufacture the prototype housing and inserts. Some of the

  12. Development of a universal medical X-ray imaging phantom prototype.

    PubMed

    Groenewald, Annemari; Groenewald, Willem A

    2016-11-08

    Diagnostic X-ray imaging depends on the maintenance of image quality that allows for proper diagnosis of medical conditions. Maintenance of image quality requires quality assurance programs on the various X-ray modalities, which consist of pro-jection radiography (including mobile X-ray units), fluoroscopy, mammography, and computed tomography (CT) scanning. Currently a variety of modality-specific phantoms are used to perform quality assurance (QA) tests. These phantoms are not only expensive, but suitably trained personnel are needed to successfully use them and interpret the results. The question arose as to whether a single universal phantom could be designed and applied to all of the X-ray imaging modalities. A universal phantom would reduce initial procurement cost, possibly reduce the time spent on QA procedures and simplify training of staff on the single device. The aim of the study was to design and manufacture a prototype of a universal phantom, suitable for image quality assurance in general X-rays, fluoroscopy, mammography, and CT scanning. The universal phantom should be easy to use and would enable automatic data analysis, pass/fail reporting, and corrective action recommendation. In addition, a universal phantom would especially be of value in low-income countries where finances and human resources are limited. The design process included a thorough investigation of commercially available phantoms. Image quality parameters necessary for image quality assurance in the different X-ray imaging modalities were determined. Based on information obtained from the above-mentioned investigations, a prototype of a universal phantom was developed, keeping ease of use and reduced cost in mind. A variety of possible phantom housing and insert materials were investigated, considering physical properties, machinability, and cost. A three-dimensional computer model of the first phantom prototype was used to manufacture the prototype housing and inserts. Some of the

  13. Quasar x-ray spectra revisited

    NASA Technical Reports Server (NTRS)

    Shastri, P.; Wilkes, B. J.; Elvis, M.; Mcdowell, J.

    1992-01-01

    A sample of 45 quasars observed by the Imaging Proportional Counter (IPC) on the Einstein satellite is used to re-examine the relationship between the soft (0.2-3.5 keV) X-ray energy index and radio-loudness. We found the following: (1) the tendency for radio-loud quasars to have systematically flatter X-ray slopes than radio-quiet quasars (RQQ's) is confirmed with the soft X-ray excess having negligible effect; (2) there is a tendency for the flatness of the X-ray slope to correlate with radio core-dominance for radio-loud quasars, suggesting that a component of the X-ray emission is relativistically beamed; (3) for the RQQ's the soft X-ray slopes, with a mean of approximately 1.0, are consistent with the slopes found at higher energies (2-10 keV) although steeper than those observed for Seyfert 1 galaxies (also 2-10 keV) where the reflection model gives a good fit to the data; (4) the correlation of FeII emission line strength with X-ray energy index is confirmed for radio-quiet quasars using a subset of 18 quasars. The radio-loud quasars show no evidence for a correlation. This relation suggests a connection between the ionizing continuum and the line emission from the broad emission line region (BELR) of radio-quiet quasars, but in the opposite sense to that predicted by current photoionization models; and (5) the correlations of X-ray slope with radio core dominance and FeII equivalent width within the radio-loud and radio-quiet sub-classes respectively imply that the observed wide range of X-ray spectral slopes is real rather than due to the large measuring uncertainties for individual objects.

  14. Globular cluster x-ray sources.

    PubMed

    Pooley, David

    2010-04-20

    Globular clusters and x-ray astronomy have a long and fruitful history. Uhuru and OSO-7 revealed highly luminous (> 10(36) ergs(-1)) x-ray sources in globular clusters, and Einstein and ROSAT revealed a larger population of low-luminosity (< 10(33) ergs(-1)) x-ray sources. It was realized early on that the high-luminosity sources were low-mass x-ray binaries in outburst and that they were orders of magnitude more abundant per unit mass in globular clusters than in the rest of the galaxy. However, the low-luminosity sources proved difficult to classify. Many ideas were put forth--low-mass x-ray binaries in quiescence (qLMXBs), cataclysmic variables (CVs), active main-sequence binaries (ABs), and millisecond pulsars (MSPs)--but secure identifications were scarce. In ROSAT observations of 55 clusters, about 25 low-luminosity sources were found. Chandra has now observed over 80 Galactic globular clusters, and these observations have revealed over 1,500 x-ray sources. The superb angular resolution has allowed for many counterpart identifications, providing clues to the nature of this population. It is a heterogeneous mix of qLMXBs, CVs, ABs, and MSPs, and it has been shown that the qLMXBs and CVs are both, in part, overabundant like the luminous LMXBs. The number of x-ray sources in a cluster correlates very well with its encounter frequency. This points to dynamical formation scenarios for the x-ray sources and shows them to be excellent tracers of the complicated internal dynamics. The relation between the encounter frequency and the number of x-ray sources has been used to suggest that we have misunderstood the dynamical states of globular clusters.

  15. X-ray in Zeta-Ori

    NASA Astrophysics Data System (ADS)

    López-García, M. A.; López-Santiago, J. L.; Albacete-Colombo, J. F.; De Castro, E.

    2013-05-01

    Nearby star-forming regions are ideal laboratories to study high-energy emission processes but they usually present high absorption what makes difficult to detect the stellar population inside the molecular complex. As young late-type stars show high X-ray emission and X-ray photons are little absorbed by interstellar material, X-ray dedicated surveys are an excellent tool to detect the low-mass stellar population in optically absorbed regions. In this work, we present a study of the star-forming region Zeta-Ori and its surroundings. We combine optical, infrared and X-ray data. Properties of the X-ray emiting plasma and infrared features of the young stellar objects detected in the XMM-Newton observation are determined. The southern part of the Orion B giant molecular cloud complex harbor other star forming regions, as NGC 2023 and NGC 2024, we use this regions to compare. We study the spectral energy distribution of X-ray sources. Combining these results with infrared, the X-ray sources are classified as class I, class II and class III objects. The X-ray spectrum and ligth curve of detected X-ray sources is analyzed to found flares. We use a extincion-independent index to select the stars with circumstellar disk, and study the relationship between the present of disk and the flare energy. The results are similar to others studies and we conclude that the coronal properties of class II and class III objects in this region do not differ significantly from each other and from stars of similar infrared class in the ONC.

  16. X-rays from Alpha Centauri

    NASA Technical Reports Server (NTRS)

    Nugent, J.; Garmire, G.

    1978-01-01

    HEAO 1 observations of soft X-ray emission from a point source in the vicinity of Alpha Cen are reported. The source, designated H1437-61, is tentatively identified with Alpha Cen, and an X-ray luminosity comparable to that of the sun in an active state is estimated. A temperature of about 500,000 K and an emission integral of 5 x 10 to the 50th per cu cm are obtained. Coronal emission is suggested as the X-ray-producing mechanism.

  17. The Future of X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.

    2013-01-01

    The most important next step is the development of X-ray optics comparable to (or better than) Chandra in angular resolution that far exceed Chandra s effective area. Use the long delay to establish an adequately funded, competitive technology program along the lines I have recommended. Don't be diverted from this objective, except for Explorer-class missions. Progress in X-ray optics, with emphasis on the angular resolution, is central to the paradigm-shifting discoveries and the contributions of X-ray astronomy to multiwavelength astrophysics over the past 51 years.

  18. Large Area X-Ray Spectroscopy Mission

    NASA Technical Reports Server (NTRS)

    Tananbaum, H.

    1997-01-01

    The Large Area X-ray Spectroscopy (LAXS) mission concept study continues to evolve strongly following the merging of the LAXS mission with the Next Generation X-ray Observatory (NGXO, PI: Nick White) into the re-named High Throughput X-ray Spectroscopy (HTXS) Mission. HTXS retains key elements of the LAXS proposal, including the use of multiple satellites for risk-reduction and cost savings. A key achievement of the program has been the recommendation by the Structure and Evolution of the Universe (SEUS) (April 1997) for a new start for the HTXS mission in the 2000-2004 timeframe.

  19. Diffractive Imaging Using Partially Coherent X Rays

    SciTech Connect

    Whitehead, L. W.; Williams, G. J.; Quiney, H. M.; Vine, D. J.; Dilanian, R. A.; Flewett, S.; Nugent, K. A.; Peele, A. G.; Balaur, E.; McNulty, I.

    2009-12-11

    The measured spatial coherence characteristics of the illumination used in a diffractive imaging experiment are incorporated in an algorithm that reconstructs the complex transmission function of an object from experimental x-ray diffraction data using 1.4 keV x rays. Conventional coherent diffractive imaging, which assumes full spatial coherence, is a limiting case of our approach. Even in cases in which the deviation from full spatial coherence is small, we demonstrate a significant improvement in the quality of wave field reconstructions. Our formulation is applicable to x-ray and electron diffraction imaging techniques provided that the spatial coherence properties of the illumination are known or can be measured.

  20. X-ray phase-contrast methods

    SciTech Connect

    Lider, V. V. Kovalchuk, M. V.

    2013-11-15

    This review is devoted to a comparative description of the methods for forming X-ray phase-contrast images of weakly absorbing (phase) objects. These include the crystal interferometer method, the Talbot interferometer method, diffraction-enhanced X-ray imaging, and the in-line method. The potential of their practical application in various fields of science and technology is discussed. The publications on the development and optimization of X-ray phase-contrast methods and the experimental study of phase objects are analyzed.

  1. "X-Ray Transients in Star-Forming Regions" and "Hard X-Ray Emission from X-Ray Bursters"

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Kaaret, Philip

    1999-01-01

    This grant funded work on the analysis of data obtained with the Burst and Transient Experiment (BATSE) on the Compton Gamma-Ray Observatory. The goal of the work was to search for hard x-ray transients in star forming regions using the all-sky hard x-ray monitoring capability of BATSE. Our initial work lead to the discovery of a hard x-ray transient, GRO J1849-03. Follow-up observations of this source made with the Wide Field Camera on BeppoSAX showed that the source should be identified with the previously known x-ray pulsar GS 1843-02 which itself is identified with the x-ray source X1845-024 originally discovered with the SAS-3 satellite. Our identification of the source and measurement of the outburst recurrence time, lead to the identification of the source as a Be/X-ray binary with a spin period of 94.8 s and an orbital period of 241 days. The funding was used primarily for partial salary and travel support for John Tomsick, then a graduate student at Columbia University. John Tomsick, now Dr. Tomsick, received his Ph.D. from Columbia University in July 1999, based partially on results obtained under this investigation. He is now a postdoctoral research scientist at the University of California, San Diego.

  2. Continuous Shape Estimation of Continuum Robots Using X-ray Images.

    PubMed

    Lobaton, Edgar J; Fu, Jinghua; Torres, Luis G; Alterovitz, Ron

    2013-05-06

    We present a new method for continuously and accurately estimating the shape of a continuum robot during a medical procedure using a small number of X-ray projection images (e.g., radiographs or fluoroscopy images). Continuum robots have curvilinear structure, enabling them to maneuver through constrained spaces by bending around obstacles. Accurately estimating the robot's shape continuously over time is crucial for the success of procedures that require avoidance of anatomical obstacles and sensitive tissues. Online shape estimation of a continuum robot is complicated by uncertainty in its kinematic model, movement of the robot during the procedure, noise in X-ray images, and the clinical need to minimize the number of X-ray images acquired. Our new method integrates kinematics models of the robot with data extracted from an optimally selected set of X-ray projection images. Our method represents the shape of the continuum robot over time as a deformable surface which can be described as a linear combination of time and space basis functions. We take advantage of probabilistic priors and numeric optimization to select optimal camera configurations, thus minimizing the expected shape estimation error. We evaluate our method using simulated concentric tube robot procedures and demonstrate that obtaining between 3 and 10 images from viewpoints selected by our method enables online shape estimation with errors significantly lower than using the kinematic model alone or using randomly spaced viewpoints.

  3. Continuous Shape Estimation of Continuum Robots Using X-ray Images

    PubMed Central

    Lobaton, Edgar J.; Fu, Jinghua; Torres, Luis G.; Alterovitz, Ron

    2015-01-01

    We present a new method for continuously and accurately estimating the shape of a continuum robot during a medical procedure using a small number of X-ray projection images (e.g., radiographs or fluoroscopy images). Continuum robots have curvilinear structure, enabling them to maneuver through constrained spaces by bending around obstacles. Accurately estimating the robot’s shape continuously over time is crucial for the success of procedures that require avoidance of anatomical obstacles and sensitive tissues. Online shape estimation of a continuum robot is complicated by uncertainty in its kinematic model, movement of the robot during the procedure, noise in X-ray images, and the clinical need to minimize the number of X-ray images acquired. Our new method integrates kinematics models of the robot with data extracted from an optimally selected set of X-ray projection images. Our method represents the shape of the continuum robot over time as a deformable surface which can be described as a linear combination of time and space basis functions. We take advantage of probabilistic priors and numeric optimization to select optimal camera configurations, thus minimizing the expected shape estimation error. We evaluate our method using simulated concentric tube robot procedures and demonstrate that obtaining between 3 and 10 images from viewpoints selected by our method enables online shape estimation with errors significantly lower than using the kinematic model alone or using randomly spaced viewpoints. PMID:26279960

  4. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    DOE PAGES

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; ...

    2015-03-02

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also presentmore » data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.« less

  5. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    PubMed Central

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-01-01

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments. PMID:26798792

  6. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    SciTech Connect

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-03-02

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  7. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy.

    PubMed

    Miaja-Avila, L; O'Neil, G C; Uhlig, J; Cromer, C L; Dowell, M L; Jimenez, R; Hoover, A S; Silverman, K L; Ullom, J N

    2015-03-01

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼10(6) photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10(7) laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  8. An indirect flat-panel detector with avalanche gain for low dose x-ray imaging: SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout)

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Li, Dan; Rowlands, J. A.; Egami, N.; Takiguchi, Y.; Nanba, M.; Honda, Y.; Ohkawa, Y.; Kubota, M.; Tanioka, K.; Suzuki, K.; Kawai, T.

    2008-03-01

    An indirect flat-imager with programmable avalanche gain and field emitter array (FEA) readout is being investigated for low-dose x-ray imaging with high resolution. 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 charge image created by HARP is read out by electron beams generated by the FEA. The proposed detector is called SAPHIRE (Scintillator Avalanche Photoconductor with HIgh Resolution Emitter readout). The avalanche gain of HARP depends on both a-Se thickness and applied electric field E Se. At E Se of > 80 V/μm, the avalanche gain can enhance the signal at low dose (e.g. fluoroscopy) and make the detector x-ray quantum noise limited down to a single x-ray photon. At high exposure (e.g. radiography), the avalanche gain can be turned off by decreasing E Se to < 70 V/μm. In this paper the imaging characteristics of the FEA readout method, including the spatial resolution and noise, were investigated experimentally using a prototype optical HARP-FEA image sensor. The potential x-ray imaging performance of SAPHIRE, especially the aspect of programmable gain to ensure wide dynamic range and x-ray quantum noise limited performance at the lowest exposure in fluoroscopy, was investigated.

  9. VETA-I x ray test analysis

    NASA Technical Reports Server (NTRS)

    Brissenden, R. J. V.; Chartas, G.; Freeman, M. D.; Hughes, J. P.; Kellogg, E. M.; Podgorski, W. A.; Schwartz, D. A.; Zhao, P.

    1992-01-01

    This interim report presents some definitive results from our analysis of the VETA-I x-ray testing data. It also provides a description of the hardware and software used in the conduct of the VETA-I x-ray test program performed at the MSFC x-ray Calibration Facility (XRCF). These test results also serve to supply data and information to include in the TRW final report required by DPD 692, DR XC04. To provide an authoritative compendium of results, we have taken nine papers as published in the SPIE Symposium, 'Grazing Incidence X-ray/EUV Optics for Astronomy and Projection Lithography' and have reproduced them as the content of this report.

  10. X-ray source for mammography

    DOEpatents

    Logan, Clinton M.

    1994-01-01

    An x-ray source utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms.

  11. X-ray ferromagnetic resonance spectroscopy

    SciTech Connect

    Boero, G.; Rusponi, S.; Bencok, P.; Popovic, R.S.; Brune, H.; Gambardella, P.

    2005-10-10

    We present a method to measure continuous-wave ferromagnetic resonance (FMR) spectra based on the core-level absorption of circularly polarized x rays. The technique is demonstrated by using a monochromatic x-ray beam incident on an yttrium-iron-garnet sample excited by a microwave field at 2.47 GHz. FMR spectra are obtained by monitoring the x-ray absorption intensity at the photon energy corresponding to the maximum of the magnetic circular dichroism effect at the iron L{sub 2,3} edges as a function of applied magnetic field. The x-ray FMR signal is shown to be energy dependent, which makes the technique element sensitive and opens up new possibilities to perform element-resolved FMR in magnetic alloys and multilayers.

  12. Description of x-ray equipment

    SciTech Connect

    Wagner, J.

    1987-12-09

    The radiographic trailer described in this report contains the x-ray equipment permitting its transportation to the place where radiographic analysis is to be performed. There the x-ray head is deposited on the ground by a winch and ramp and the trailer is moved away. While the trailer is in motion the water hoses and electrical cables connecting the x-ray head to the rest of the equipment are automatically unwinding from the respective drums and deposited on the ground. The maximum distance between the trailer and the x-ray head is 300 ft. After positioning the trailer, the control console is placed at the distance of up to 150 ft from it, while the control cable connecting the console to the trailer is unwinding from its cable drum. The main features of the basic assemblies inside the trailer are described in this document. Reference CAPE-3013

  13. X-Ray Exam: Scoliosis (For Parents)

    MedlinePlus

    ... image is recorded on a computer or special film. The scoliosis X-ray includes the thoracic spine ( ... for scoliosis during regular physical exams, and some schools also test for scoliosis. If scoliosis is suspected, ...

  14. X-ray holography in-flight

    NASA Astrophysics Data System (ADS)

    Gorkhover, Tais; Ulmer, Anatoli; Ferguson, Ken; Bucher, Max; Ekeberg, Tomas; Hantke, Max; Daurer, Benedikt; Nettelblad, Carl; Bielecki, Johan; Faigel, Guila; Hasse, Dirk; Morgan, Andrew; Mühlig, Kerstin; Seibert, Marvin; Chapman, Henry; Hajdu, Janos; Maia, Filipe; Moeller, Thomas; Bostedt, Christoph

    2016-05-01

    The advent of X-ray free-electron lasers, delivering ultra intense femtosecond X-ray flashes, opens the door for structure determination of single nanoparticles and biosamples with single shots. The first X-ray diffraction imaging experiments at LCLS delivered promising results on samples in the gas phase. However, the reconstruction of non-periodic structures is still challenging due to the loss of phase information. Meanwhile, X-ray holographic approaches allow for recording the phase directly into the diffraction image. In my talk, I will present the first successful proof-of-principle experiment for ``in-flight''-holography with free viruses. Our experiments pave the way for unique studies on levitating nanospecimen that are of central interest in several scientific communities including atmosphere research, chemistry, material sciences, and studies on matter under extreme conditions.

  15. X-Ray Exam: Femur (Upper Leg)

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... a radiologist (a doctor who's specially trained in reading and interpreting X-ray images). The radiologist will ...

  16. X-Ray Exam: Scoliosis (For Parents)

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... by a radiologist (a doctor specially trained in reading and interpreting X-ray images). The radiologist will ...

  17. X-Ray Exam: Neck (For Parents)

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... a radiologist (a doctor who's specially trained in reading and interpreting X-ray images). The radiologist will ...

  18. X-Ray Background Survey Spectrometer (XBSS)

    NASA Technical Reports Server (NTRS)

    Sanders, W. T. (Principal Investigator); Paulos, R. J.

    1996-01-01

    The objective of this investigation was to perform a spectral survey of the low energy diffuse X-ray background using the X-ray Background Survey Spectrometer (XBSS) on board the Space Station Freedom (SSF). XBSS obtains spectra of the X-ray diffuse background in the 11-24 A and 44-84 A wavelength intervals over the entire sky with 15 deg spatial resolution. These X-rays are almost certainly from a very hot (10(exp 6) K) component of the interstellar medium that is contained in regions occupying a large fraction of the interstellar volume near the Sun. Astrophysical plasmas near 10(exp 6) K are rich in emission lines, and the relative strengths of these lines, besides providing information about the physical conditions of the emitting gas, also provide information about its history and heating mechanisms.

  19. The sensational discovery of X-rays

    NASA Astrophysics Data System (ADS)

    Maddox, John

    1995-05-01

    W. C. Röntgen discovered X-rays about this time a century ago. Within a few months, Becquerel was making the first observations of radioactivity. But the beginnings of the then new physics were not a tidy business.

  20. Chest X-Ray (Chest Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  1. X-ray transmission microscope development

    NASA Technical Reports Server (NTRS)

    Kaukler, William F.; Rosenberger, Franz E.

    1995-01-01

    This report covers the third 6 month period, from February 28, 1995 to August 31, 1995, under this contract. The main efforts during this period were the construction of the X-ray furnace, evaluation and selection of the CCD technology for the X-ray camera, solidification experiments with Al alloys and Al-zirconia composites in the prototype furnace, evaluation of specimens for the particle pushing flight experiment - PEPSI, measurements of emitted spectra from X-ray source, testing of the high resolution X-ray test targets, and the establishment of criteria for and selection of peripheral equipment. In addition to these tasks, two presentations were prepared in this period; one for the AIAA Microgravity Symposium and another for the Gordon Conference on Gravitational Effects in Pyisico-Chemical Systems.

  2. X-ray transmission microscope development

    NASA Astrophysics Data System (ADS)

    Kaukler, William F.; Rosenberger, Franz E.

    1995-08-01

    This report covers the third 6 month period, from February 28, 1995 to August 31, 1995, under this contract. The main efforts during this period were the construction of the X-ray furnace, evaluation and selection of the CCD technology for the X-ray camera, solidification experiments with Al alloys and Al-zirconia composites in the prototype furnace, evaluation of specimens for the particle pushing flight experiment - PEPSI, measurements of emitted spectra from X-ray source, testing of the high resolution X-ray test targets, and the establishment of criteria for and selection of peripheral equipment. In addition to these tasks, two presentations were prepared in this period; one for the AIAA Microgravity Symposium and another for the Gordon Conference on Gravitational Effects in Pyisico-Chemical Systems.

  3. X-ray source for mammography

    DOEpatents

    Logan, C.M.

    1994-12-20

    An x-ray source is described utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms. 6 figures.

  4. X ray opacity in cluster cooling flows

    NASA Technical Reports Server (NTRS)

    Wise, Michael W.; Sarazin, Craig L.

    1993-01-01

    We have calculated the emergent x-ray properties for a set of spherically symmetric, steady-state cluster cooling flow models including the effects of radiative transfer. Opacity due to resonant x-ray lines, photoelectric absorption, and electron scattering have been included in these calculations, and homogeneous and inhomogeneous gas distributions were considered. The effects of photoionization opacity are small for both types of models. In contrast, resonant line optical depths can be quite high in both homogeneous and inhomogeneous models. The presence of turbulence in the gas can significantly lower the line opacity. We find that integrated x-ray spectra for the flow cooling now are only slightly affected by radiative transfer effects. However x-ray line surface brightness profiles can be dramatically affected by radiative transfer. Line profiles are also strongly affected by transfer effects. The combined effects of opacity and inflow cause many of the lines in optically thick models to be asymmetrical.

  5. Impulsive solar X-ray bursts

    NASA Technical Reports Server (NTRS)

    Crannell, C. J.; Frost, K. J.; Maetzler, C.; Ohki, K.; Saba, J. L.

    1977-01-01

    A set of 22 simple, impulsive solar flares, identified in the OSO-5 hard X-ray data, were analyzed together with coincident microwave and meterwave radio observations. The rise times and fall times of the X-ray bursts are found to be highly correlated and effectively equal, strongly suggesting a flare energizing mechanism that is reversible. The good time resolution available for these observations reveals that the microwave emission is influenced by an additional process, evident in the tendency of the microwave emission to peak later and decay more slowly than the symmetric X-ray bursts. Meterwave emission is observed in coincidence with the 5 events which show the strongest time correlation between the X-ray and microwave burst structure. This meterwave emission is characterized by U-burst radiation, indicating confinement of the flare source.

  6. Interlaced X-ray diffraction computed tomography

    PubMed Central

    Vamvakeros, Antonios; Jacques, Simon D. M.; Di Michiel, Marco; Senecal, Pierre; Middelkoop, Vesna; Cernik, Robert J.; Beale, Andrew M.

    2016-01-01

    An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the method for studying an Mn–Na–W/SiO2 fixed-bed reactor in situ is demonstrated. Additionally, the opportunities to improve the data-collection strategy further, enabling post-collection tuning between statistical, temporal and spatial resolutions, are discussed. In principle, the interlaced scanning approach can also be applied to other pencil-beam tomographic techniques, like X-ray fluorescence computed tomography, X-ray absorption fine structure computed tomography, pair distribution function computed tomography and tomographic scanning transmission X-ray microscopy. PMID:27047305

  7. Experimental X-Ray Ghost Imaging

    NASA Astrophysics Data System (ADS)

    Pelliccia, Daniele; Rack, Alexander; Scheel, Mario; Cantelli, Valentina; Paganin, David M.

    2016-09-01

    We report an experimental proof of principle for ghost imaging in the hard-x-ray energy range. We use a synchrotron x-ray beam that is split using a thin crystal in Laue diffraction geometry. With an ultrafast imaging camera, we are able to image x rays generated by isolated electron bunches. At this time scale, the shot noise of the synchrotron emission process is measurable as speckles, leading to speckle correlation between the two beams. The integrated transmitted intensity from a sample located in the first beam is correlated with the spatially resolved intensity measured in the second, empty, beam to retrieve the shadow of the sample. The demonstration of ghost imaging with hard x rays may open the way to protocols to reduce radiation damage in medical imaging and in nondestructive structural characterization using free electron lasers.

  8. Laboratory Data for X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Beiersdorfer, P.; Brown, G. V.; Chen, H.; Gu, M.-F.; Kahn, S. M.; Lepson, J. K.; Savin, D. W.; Utter, S. B.

    2000-01-01

    Laboratory facilities have made great strides in producing large sets of reliable data for X-ray astronomy, which include ionization and recombination cross sections needed for charge balance calculations as well as the atomic data needed for interpreting X-ray line formation. We discuss data from the new generation sources and pay special attention to the LLNL electron beam ion trap experiment, which is unique in its ability to provide direct laboratory access to spectral data under precisely controlled conditions that simulate those found in many astrophysical plasmas. Examples of spectral data obtained in the 1-160 A wavelength range are given illustrating the type of laboratory X-ray data produced in support of such missions as Chandra, X-Ray Multi-Mirror telescope (XMM), Advanced Satellite for Cosmology and Astrophysics (ASCA) and Extreme Ultraviolet Explorer Satellite (EUVE).

  9. Spectra of cosmic x-ray sources

    SciTech Connect

    Holt, S.S.; Mccray, R.

    1982-02-01

    X-ray measurements provide the most direct probes of astrophysical environments with temperatures exceeding one million K. Progress in experimental research utilizing dispersive techniques (e.g., Bragg and grating spectroscopy) is considerably slower than that in areas utilizing photometric techniques, because of the relative inefficiency of the former for the weak X-ray signals from celestial sources. As a result, the term spectroscopy as applied to X-ray astronomy has traditionally satisfied a much less restrictive definition (in terms of resolving power) than it has in other wavebands. Until quite recently, resolving powers of order unity were perfectly respectable, and still provide (in most cases) the most useful spectroscopic data. In the broadest sense, X-ray photometric measurements are spectroscopic, insofar as they represent samples of the overall electromagnetic continua of celestial objects.

  10. Why Do I Need X-Rays?

    MedlinePlus

    ... information you need from the Academy of General Dentistry Sunday, April 9, 2017 About | Contact InfoBites Quick ... Related Articles: X-Rays The Academy of General Dentistry (AGD) Sets the Record Straight on Dental X- ...

  11. 5.8 X-ray Calorimeters

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2008-01-01

    X-ray calorimeter instruments for astrophysics have seen rapid development since they were invented in 1984. The prime instrument on all currently planned X-ray spectroscopic observatories is based on calorimeter technology. This relatively simple detection concept that senses the energy of an incident photon by measuring the temperature rise of an absorber material at very low temperatures, can form the basis of a very high performance, non-dispersive spectrometer. State-of-the-art calorimeter instruments have resolving powers of over 3000, large simultaneous band-passes, and near unit efficiency. This coupled with the intrinsic imaging capability of a pixilated x-ray calorimeter array, allows true spectral-spatial instruments to be constructed. In this chapter I briefly review the detection scheme, the state-of-the-art in X-ray calorimeter instruments and the future outlook for this technology.

  12. Tuberculosis, advanced - chest x-rays (image)

    MedlinePlus

    Tuberculosis is an infectious disease that causes inflammation, the formation of tubercules and other growths within tissue, ... death. These chest x-rays show advanced pulmonary tuberculosis. There are multiple light areas (opacities) of varying ...

  13. X-ray induced optical reflectivity

    NASA Astrophysics Data System (ADS)

    Durbin, Stephen M.

    2012-12-01

    The change in optical reflectivity induced by intense x-ray pulses can now be used to study ultrafast many body responses in solids in the femtosecond time domain. X-ray absorption creates photoelectrons and core level holes subsequently filled by Auger or fluorescence processes, and these excitations ultimately add conduction and valence band carriers that perturb optical reflectivity. Optical absorption associated with band filling and band gap narrowing is shown to explain the basic features found in recent measurements on an insulator (silicon nitride, Si3N4), a semiconductor (gallium arsenide, GaAs), and a metal (gold, Au), obtained with ˜100 fs x-ray pulses at 500-2000 eV and probed with 800 nm laser pulses. In particular GaAs exhibits an abrupt drop in reflectivity, persisting only for a time comparable to the x-ray excitation pulse duration, consistent with prompt band gap narrowing.

  14. Dental x-ray diagnostic installation

    SciTech Connect

    Grassme, U.

    1985-02-19

    An exemplary embodiment comprises an exposure unit including an X-ray tube and a cassette holder rotatable about vertical axes and between which the head of the patient is disposed. A radiation detector is disposed at the cassette holder for supplying an electrical signal corresponding to the dose rate when it is struck by X-rays and being interconnected with an X-ray tube voltage controller and a dose rate regulator in such manner that the X-ray tube voltage is influenced by the output of the radiation detector to control the dose rate to a value producing an optimum film blackening. A function generator determining the speed of the exposure unit is provided in which a speed curve is stored given which the radiation dose influencing the film is approximately constant.

  15. X-ray grid-detector apparatus

    DOEpatents

    Boone, John M.; Lane, Stephen M.

    1998-01-27

    A hybrid grid-detector apparatus for x-ray systems wherein a microchannel plate structure has an air-interspaced grid portion and a phosphor/optical fluid-filled grid portion. The grids are defined by multiple adjacent channels separated by lead-glass septa. X-rays entering the air-interspaced grid portion at an angle of impingement upon the septa are attenuated, while non-impinging x-rays pass through to the phosphor/fluid filled portion. X-ray energy is converted to luminescent energy in the phosphor/fluid filled portion and the resultant beams of light are directed out of the phosphor/optical fluid filled portion to an imaging device.

  16. Interlaced X-ray diffraction computed tomography.

    PubMed

    Vamvakeros, Antonios; Jacques, Simon D M; Di Michiel, Marco; Senecal, Pierre; Middelkoop, Vesna; Cernik, Robert J; Beale, Andrew M

    2016-04-01

    An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the method for studying an Mn-Na-W/SiO2 fixed-bed reactor in situ is demonstrated. Additionally, the opportunities to improve the data-collection strategy further, enabling post-collection tuning between statistical, temporal and spatial resolutions, are discussed. In principle, the interlaced scanning approach can also be applied to other pencil-beam tomographic techniques, like X-ray fluorescence computed tomography, X-ray absorption fine structure computed tomography, pair distribution function computed tomography and tomographic scanning transmission X-ray microscopy.

  17. Ptychographic coherent x-ray surface scattering imaging

    NASA Astrophysics Data System (ADS)

    Kim, Jong Woo; Jiang, Zhang; Sun, Tao; Wang, Jin

    Lensless x-ray coherent diffraction imaging enables the determination of nano-scaled structures in physical and biological sciences. Several coherent diffractive imaging (CDI) methods have been developed in both transmission and reflection modes such as Bragg CDI, plane-wave CDI, Fresnel CDI, coherent surface scattering imaging (CSSI) and so on. The grazing-incidence coherent surface scattering (CSSI) technique, which is recently developed by T. Sun et al., takes advantage of enhanced x-ray surface scattering and interference near total external reflection, and thereby overcomes some limitations that the transmission mode have. However, the sample size can be investigated is limited by x-ray beam size because the sample is supposed to be isolated. We incorporated ptychographic algorithm with coherent surface scattering imaging to overcome this limitation and make it more useful and applicable. The ptychographic coherent surface scattering imaging technique enables us to measure 2D roughness of the flat surface such as thin film and silicon wafer regardless of the surface area. LDRD.

  18. X-ray microscopy of soft and hard human tissues

    SciTech Connect

    Müller, Bert Schulz, Georg Deyhle, Hans Stalder, Anja K. Ilgenstein, Bernd Holme, Margaret N. Hieber, Simone E.; Beckmann, Felix

    2016-01-28

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments.

  19. X-ray microscopy of soft and hard human tissues

    NASA Astrophysics Data System (ADS)

    Müller, Bert; Schulz, Georg; Deyhle, Hans; Stalder, Anja K.; Ilgenstein, Bernd; Holme, Margaret N.; Weitkamp, Timm; Beckmann, Felix; Hieber, Simone E.

    2016-01-01

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments.

  20. Principles of X-ray Navigation

    SciTech Connect

    Hanson, John Eric; /SLAC

    2006-03-17

    X-ray navigation is a new concept in satellite navigation in which orientation, position and time are measured by observing stellar emissions in x-ray wavelengths. X-ray navigation offers the opportunity for a single instrument to be used to measure these parameters autonomously. Furthermore, this concept is not limited to missions in close proximity to the earth. X-ray navigation can be used on a variety of missions from satellites in low earth orbit to spacecraft on interplanetary missions. In 1997 the Unconventional Stellar Aspect Experiment (USA) will be launched as part of the Advanced Research and Global Observation Satellite (ARGOS). USA will provide the first platform for real-time experimentation in the field of x-ray navigation and also serves as an excellent case study for the design and manufacturing of space qualified systems in small, autonomous groups. Current techniques for determining the orientation of a satellite rely on observations of the earth, sun and stars in infrared, visible or ultraviolet wavelengths. It is possible to use x-ray imaging devices to provide arcsecond level measurement of attitude based on star patterns in the x-ray sky. This technique is explored with a simple simulation. Collimated x-ray detectors can be used on spinning satellites to provide a cheap and reliable measure of orientation. This is demonstrated using observations of the Crab Pulsar taken by the high Energy Astronomy Observatory (HEAO-1) in 1977. A single instrument concept is shown to be effective, but dependent on an a priori estimate of the guide star intensity and thus susceptible to errors in that estimate. A star scanner based on a differential measurement from two x-ray detectors eliminates the need for an a priori estimate of the guide star intensity. A first order model and a second order model of the two star scanner concepts are considered. Many of the stars that emit in the x-ray regime are also x-ray pulsars with frequency stability approaching a

  1. X-ray scattering from dense plasmas

    NASA Astrophysics Data System (ADS)

    McSherry, Declan Joseph

    Dense plasmas were studied by probing them with kilovolt x-rays and measuring those scattered at various angles. The laser produced x-ray source emitted Ti He alpha 4.75 keV x-rays. Two different plasma types were explored. The first was created by laser driven shocks on either side of a sample foil consisting of 2 micron thickness of Al, sandwiched between two 1 micron CH layers. We have observed a peak in the x-ray scattering cross section, indicating diffraction from the plasma. However, the experimentally inferred plasma density, did not always agree broadly with the hydrodynamic simulation MEDX (A modified version of MEDUSA). The second plasma type that we studied was created by soft x-ray heating on either side of a sample foil, this time consisting of 1 micron thickness of Al, sandwiched between two 0.2 micron CH layers. Two foil targets, each consisting of a 0.1 micron thick Au foil mounted on 1 micron of CH, were placed 4 mm from the sample foil. The soft x-rays were produced by laser irradiating these two foil targets. We found that, 0.5 ns after the peak of the laser heating pulses, that the measured cross sections more closely matched those simulated using the Thomas Fermi model than the Inferno model. Later in time, at 2 ns, the plasma is approaching a weakly coupled state. This is the first time x-ray scattering cross sections have been measured from dense plasmas generated by radiatively heating both sides of the sample. Moreover, these are absolute values typically within a factor of two of expectation for early x-ray probe times.

  2. X-ray physics subpanel summary.

    NASA Astrophysics Data System (ADS)

    Lin, R. P.; Dennis, B. R.

    The X-ray subpanel of the P/OF Workshop provided the opportunity to get input from a broad-based scientific community, including SMM experimenters and data analysts, solar flare theorists, and ground-based observers, on scientific and technical trade-offs involved in the X-ray instrumentation. The basic objective was to review the strawman payload set up for the Pinhole/Occulter Facility in the light of scientific developments of the last five years.

  3. X-ray physics subpanel summary.

    NASA Astrophysics Data System (ADS)

    Lin, R. P.; Dennis, B. R.

    1986-04-01

    The X-ray subpanel of the P/OF Workshop provided the opportunity to get input from a broad-based scientific community, including SMM experimenters and data analysts, solar flare theorists, and ground-based observers, on scientific and technical trade-offs involved in the X-ray instrumentation. The basic objective was to review the strawman payload set up for the Pinhole/Occulter Facility in the light of scientific developments of the last five years.

  4. Real-Time X-Ray Inspection

    NASA Technical Reports Server (NTRS)

    Bulthuis, Ronald V.

    1988-01-01

    X-ray imaging instrument adapted to continuous scanning. Modern version of fluoroscope enables rapid x-ray inspection of parts. Developed for detection of buckling in insulated ducts. Uses radiation from radioactive gadolinium or thallium source. Instrument weighs only 6 1/2 lb. Quickly scanned by hand along duct surface, providing real-time image. Based on Lixiscope, developed at Goddard Space Flight Center.

  5. Spacecraft Navigation Using X-ray Pulsars

    DTIC Science & Technology

    2006-01-01

    make them attractive as potential natural naviga- tion beacons and why a practical implementation looks most feasible in the X-ray band. We then...describe the history of the X-ray navigation program at NRL up through our current Defense Advanced Research Proj- ects Agency (DARPA) program. Finally, we...that produce the powerful radiation beams. These pulsars then turn off and inhabit the “pulsar graveyard.” During their lives, these pulsars make very

  6. Galaxies in the X-ray Band

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann

    2008-01-01

    This talk will provide a brief review of progress on X-ray emission from normal (non-AGN) galaxy populations, including important constraints on the evolution of accreting binary populations over important cosmological timescales. We will also look to the future, anticipating constraints from near-term imaging hard X-ray missions such as NuSTAR, Simbol-X and NeXT and then the longer-term prospects for studying galaxies with the Generation-X mission.

  7. Galaxies in the X-Ray Band

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann

    2008-01-01

    This talk will provide a brief review of progress an X-ray emission from normal (non-AGN) galaxy populations, including important constraints on the evolution of accreting binary populations over important cosmological timescales. We will also look to the future, anticipating constraints from near-term imaging hard X-ray missions such as NuSTAR, Simbol-X and NeXT and then the longer-term prospects for studying galaxies with the Generation-X mission,

  8. Parametric X-rays at FAST

    SciTech Connect

    Sen, Tanaji

    2016-06-01

    We discuss the generation of parametric X-rays (PXR) in the photoinjector at the new FAST facility at Fermilab. Detailed calculations of the intensity spectrum, energy and angular widths and spectral brilliance with a diamond crystal are presented. We also report on expected results with PXR generated while the beam is channeling. The low emittance electron beam makes this facility a promising source for creating brilliant X-rays.

  9. The high energy X-ray universe

    PubMed Central

    Giacconi, Riccardo

    2010-01-01

    Since its beginning in the early 1960s, the field of X-ray astronomy has exploded, experiencing a ten-billion-fold increase in sensitivity, which brought it on par with the most advanced facilities at all wavelengths. I will briefly describe the revolutionary first discoveries prior to the launch of the Chandra and XMM-Newton X-ray observatories, present some of the current achievements, and offer some thoughts about the future of this field. PMID:20404148

  10. Should surgeons control fluoroscopy during urology procedures?

    PubMed Central

    Setterfield, Jeremy; Watterson, James; Playfair, Mathew; Lavallée, Luke T.; Roberts, Matthew; Blew, Brian; Oake, J. Stuart

    2016-01-01

    Introduction Our study explored the impact of switching from surgeon- to radiation technologist (RT)-controlled fluoroscopy on fluoroscopy and operative times. We also identified factors impacting fluoroscopy and operative times for ureteroscopy (URS) with laser lithotripsy. Methods Patients undergoing urological procedures requiring fluoroscopy six months before and after the change from surgeon- to RT-controlled fluoroscopy were identified. Median fluoroscopy and operative times were compared between cohorts. Subgroup analyses were performed based on procedure performed. A multivariate analysis identified factors associated with increased fluoroscopy and operative times for URS with laser lithotripsy. Results Overall, no difference was found between surgeon and RT cohorts for fluoroscopy (58.0 vs. 56.7 seconds; p=0.34) or operative times (39 vs. 36 minutes; p=0.14). For URS with laser lithotripsy, fluoroscopy and operative times were longer in the surgeon-controlled cohort (76.0 vs. 54.0 seconds; p<0.01 and 48 vs. 40 minutes; p<0.01, respectively). For URS only, fluoroscopy time was decreased in the surgeon-controlled cohort (47.0 vs. 73.0 seconds; p=0.01). For URS with laser lithotripsy, factors independently associated with increased fluoroscopy time were male sex, flexible URS, glidewire use, and difficult ureteric stent insertion (p<0.05). Flexible ureteroscopy, glidewire use, previous ureteric stent placement, and difficult ureteric stent insertion were independently associated with increased operative time (p<0.05). Conclusions Fluoroscopy and operative times are not significantly influenced by who controls fluoroscopy during urologic procedures. Patients undergoing URS with laser lithotripsy have decreased fluoroscopy and operative times with RT-controlled fluoroscopy. Patients undergoing URS only have decreased fluoroscopy times with surgeon-controlled fluoroscopy. PMID:28028425

  11. 3D X-Ray Luggage-Screening System

    NASA Technical Reports Server (NTRS)

    Fernandez, Kenneth

    2006-01-01

    A three-dimensional (3D) x-ray luggage- screening system has been proposed to reduce the fatigue experienced by human inspectors and increase their ability to detect weapons and other contraband. The system and variants thereof could supplant thousands of xray scanners now in use at hundreds of airports in the United States and other countries. The device would be applicable to any security checkpoint application where current two-dimensional scanners are in use. A conventional x-ray luggage scanner generates a single two-dimensional (2D) image that conveys no depth information. Therefore, a human inspector must scrutinize the image in an effort to understand ambiguous-appearing objects as they pass by at high speed on a conveyor belt. Such a high level of concentration can induce fatigue, causing the inspector to reduce concentration and vigilance. In addition, because of the lack of depth information, contraband objects could be made more difficult to detect by positioning them near other objects so as to create x-ray images that confuse inspectors. The proposed system would make it unnecessary for a human inspector to interpret 2D images, which show objects at different depths as superimposed. Instead, the system would take advantage of the natural human ability to infer 3D information from stereographic or stereoscopic images. The inspector would be able to perceive two objects at different depths, in a more nearly natural manner, as distinct 3D objects lying at different depths. Hence, the inspector could recognize objects with greater accuracy and less effort. The major components of the proposed system would be similar to those of x-ray luggage scanners now in use. As in a conventional x-ray scanner, there would be an x-ray source. Unlike in a conventional scanner, there would be two x-ray image sensors, denoted the left and right sensors, located at positions along the conveyor that are upstream and downstream, respectively (see figure). X-ray illumination

  12. 3D localization of electrophysiology catheters from a single x-ray cone-beam projection

    SciTech Connect

    Robert, Normand Polack, George G.; Sethi, Benu; Rowlands, John A.; Crystal, Eugene

    2015-10-15

    Purpose: X-ray images allow the visualization of percutaneous devices such as catheters in real time but inherently lack depth information. The provision of 3D localization of these devices from cone beam x-ray projections would be advantageous for interventions such as electrophysiology (EP), whereby the operator needs to return a device to the same anatomical locations during the procedure. A method to achieve real-time 3D single view localization (SVL) of an object of known geometry from a single x-ray image is presented. SVL exploits the change in the magnification of an object as its distance from the x-ray source is varied. The x-ray projection of an object of interest is compared to a synthetic x-ray projection of a model of said object as its pose is varied. Methods: SVL was tested with a 3 mm spherical marker and an electrophysiology catheter. The effect of x-ray acquisition parameters on SVL was investigated. An independent reference localization method was developed to compare results when imaging a catheter translated via a computer controlled three-axes stage. SVL was also performed on clinical fluoroscopy image sequences. A commercial navigation system was used in some clinical image sequences for comparison. Results: SVL estimates exhibited little change as x-ray acquisition parameters were varied. The reproducibility of catheter position estimates in phantoms denoted by the standard deviations, (σ{sub x}, σ{sub y}, σ{sub z}) = (0.099 mm,  0.093 mm,  2.2 mm), where x and y are parallel to the detector plane and z is the distance from the x-ray source. Position estimates (x, y, z) exhibited a 4% systematic error (underestimation) when compared to the reference method. The authors demonstrated that EP catheters can be tracked in clinical fluoroscopic images. Conclusions: It has been shown that EP catheters can be localized in real time in phantoms and clinical images at fluoroscopic exposure rates. Further work is required to characterize

  13. Hard x ray highlights of AR 5395

    NASA Technical Reports Server (NTRS)

    Schwartz, R. A.; Dennis, Brian R.

    1989-01-01

    Active Region 5395 produced an exceptional series of hard x ray bursts notable for their frequency, intensity, and impulsivity. Over the two weeks from March 6 to 19, 447 hard x ray flares were observed by the Hard X Ray Burst Spectrometer on Solar Maximum Mission (HXRBS/SMM), a rate of approx. 35 per day which exceeded the previous high by more than 50 percent. During one 5 day stretch, more than 250 flares were detected, also a new high. The three largest GOES X-flares were observed by HXRBS and had hard x ray rates over 100,000 s(exp -1) compared with only ten flares above 100,000(exp -1) during the previous nine years of the mission. An ongoing effort for the HXRBS group has been the correlated analysis of hard x ray data with flare data at other wavelengths with the most recent emphasis on those measurements with spatial information. During a series of bursts from AR 5395 at 1644 to 1648 UT on 12 March 1989, simultaneous observations were made by HXRBS and UVSP (Ultra Violet Spectrometer Polarimeter) on SMM, the two-element Owens Valley Radio Observatory (OVRO) interferometric array, and R. Canfield's H-alpha Echelle spectrograph at the National Solar Observatory at Sacramento Peak. The data show strong correlations in the hard x ray, microwave, and UV lightcurves. This event will be the subject of a combined analysis.

  14. The SAS-3 X-ray observatory

    NASA Technical Reports Server (NTRS)

    Mayer, W. F.

    1975-01-01

    The experiment section of the Small Astronomy Satellite-3 (SAS-3) launched in May 1975 is an X-ray observatory intended to determine the location of bright X-ray sources to an accuracy of 15 arc-seconds; to study a selected set of sources over a wide energy range, from 0.1 to 55 keV, while performing very specific measurements of the spectra and time variability of known X-ray sources; and to monitor the sky continuously for X-ray novae, flares, and unexpected phenomena. The improvements in SAS-3 spacecraft include a clock accurate to 1 part in 10 billion, rotatable solar panels, a programmable data format, and improved nutation damper, a delayed command system, improved magnetic trim and azimuth control systems. These improvements enable SAS-3 to perform three-axis stabilized observations of any point on the celestial sphere at any time of the year. The description of the experiment section and the SAS-3 operation is followed by a synopsis of scientific results obtained from the observations of X-ray sources, such as Vela X-1 (supposed to be an accreting neutron star), a transient source of hard X-ray (less than 36 min in duration) detected by SAS-3, the Crab Nebula pulsar, the Perseus cluster of galaxies, and the Vela supernova remnant.

  15. Compton backscattered collimated x-ray source

    DOEpatents

    Ruth, Ronald D.; Huang, Zhirong

    1998-01-01

    A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

  16. Compton backscattered collmated X-ray source

    DOEpatents

    Ruth, Ronald D.; Huang, Zhirong

    2000-01-01

    A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

  17. Optics Developments for X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Ramsey, Brian

    2014-01-01

    X-ray optics has revolutionized x-ray astronomy. The degree of background suppression that these afford, have led to a tremendous increase in sensitivity. The current Chandra observatory has the same collecting area (approx. 10(exp 3)sq cm) as the non-imaging UHURU observatory, the first x-ray observatory which launched in 1970, but has 5 orders of magnitude more sensitivity due to its focusing optics. In addition, its 0.5 arcsec angular resolution has revealed a wealth of structure in many cosmic x-ray sources. The Chandra observatory achieved its resolution by using relatively thick pieces of Zerodur glass, which were meticulously figured and polished to form the four-shell nested array. The resulting optical assembly weighed around 1600 kg, and cost approximately $0.5B. The challenge for future x-ray astronomy missions is to greatly increase the collecting area (by one or more orders of magnitude) while maintaining high angular resolution, and all within realistic mass and budget constraints. A review of the current status of US optics for x-ray astronomy will be provided along with the challenges for future developments.

  18. X-ray Eyes on Tempel

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: X-ray Eyes on Tempel

    This false-color image shows comet Tempel 1 as seen by Chandra X-ray Observatory on June 30, 2005, Universal Time. The comet was bright and condensed. The X-rays observed from comets are caused by an interaction between highly charged oxygen in the solar wind and neutral gases from the comet.

    The observatory detected X-rays with an energy of 0.3 to 1.0 kilo electron Volts. The bulk of the X-rays were between 0.5 and 0.7 kilo electron Volts.

    Chandra will observe the comet for 18 hours during and after the time when NASA's Deep Impact impactor probe collides with Tempel 1 at 10:52 p.m. Pacific time, July 3 (1:52 a.m. Eastern time, July 4). The material ejected from the crater could cause the interaction region, and thus the X-ray emission, to move toward the Sun.

  19. The potential of X-ray polarimetry

    NASA Astrophysics Data System (ADS)

    Tamborra, F.

    2014-07-01

    Up-scattering of low-energy photons by Inverse Compton processes in a hot gas of electrons (i.e. Comptonization) is a common astrophysical mechanism particularly important in accreting systems like X-ray binaries (XRBs) and Active Galactic Nuclei (AGN). Polarization signals produced by scattering strongly depend on the optical thickness and geometry of the scattering medium as well as on the observer's viewing angle. The polarization degree and angle can be used to constrain, for example, the still unknown parameters which characterize the hot corona responsible for the production of X-ray radiation in AGN or the dominant mechanism responsible for the broadening of the Iron K-alpha emission line whose origin is still a matter of debate in the case of low mass X-ray binaries with a neutron star. Conducting accurate Monte Carlo simulations we show the potential of X-ray polarimetry, a new perspective of X-ray astronomy. The spectroscopic part of our results can already be exploited today in the light of XMM-Newton and Chandra data and is even more appealing in the perspective of data from NuStar and future X-ray missions.

  20. Compton backscattered collimated x-ray source

    DOEpatents

    Ruth, R.D.; Huang, Z.

    1998-10-20

    A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

  1. The X-ray imager on AXO

    NASA Astrophysics Data System (ADS)

    Budtz-Jørgensen, C.; Kuvvetli, I.; Westergaard, N. J.; Jonasson, P.; Reglero, V.; Eyles, C.

    2001-02-01

    DSRI has initiated a development program of CZT X-ray and gamma-ray detectors employing strip readout techniques. A dramatic improvement of the energy response was found operating the detectors as the so-called drift detectors. For the electronic readout, modern ASIC chips were investigated. Modular design and the low-power electronics will make large area detectors using the drift strip method feasible. The performance of a prototype CZT system will be presented and discussed. One such detector system has been proposed for future space missions: the X-Ray Imager (XRI) on the Atmospheric X-ray Observatory (AXO), which is a mission proposed to the Danish Small Satellite Program and is dedicated to observations of X-ray generating processes in the Earth's atmosphere. Of special interest will be simultaneous optical and X-ray observations of sprites that are flashes appearing directly above an active thunderstorm system. Additional objective is a detailed mapping of the auroral X-ray and optical emission. XRI comprises a coded mask and a 20×40 cm 2 CZT detector array covering an energy range from 5 to 200 keV.

  2. X-ray laser driven gold targets

    SciTech Connect

    Petrova, Tz. B. Whitney, K. G.; Davis, J.

    2014-03-15

    The femtosecond population dynamics of gold irradiated by a coherent high-intensity (>10{sup 17} W/cm{sup 2}) x-ray laser pulse is investigated theoretically. There are two aspects to the assembled model. One is the construction of a detailed model of platinum-like gold inclusive of all inner-shell states that are created by photoionization of atomic gold and decay either by radiative or Auger processes. Second is the computation of the population dynamics that ensues when an x-ray pulse is absorbed in gold. The hole state generation depends on the intensity and wavelength of the driving x-ray pulse. The excited state populations reached during a few femtosecond timescales are high enough to generate population inversions, whose gain coefficients are calculated. These amplified lines in the emitted x-ray spectrum provide important diagnostics of the radiation dynamics and also suggest a nonlinear way to increase the frequency of the coherent output x-ray pulses relative to the frequency of the driver input x-ray pulse.

  3. Scattered radiation risk to the lens of the eyes for staff involved in using mobile C-arm fluoroscopy unit: Which position is riskiest?

    SciTech Connect

    Salleh, H.; Matori, M. K.; Isa, M. J. M.; Samat, S. B.

    2015-09-25

    Cataractogenesis is something to be concerned by radiologist and radiographer who work extensively in fluoroscopy. The increasing use of fluoroscopy or interventional fluoroscopy has to come with safety awareness on scattered radiation risk for staff performing the procedure. This study is looking into the radiation risk to the lens of the eyes for staff involved in fluoroscopy using the mobile C-arm fluoroscopy unit. The Toshiba SXT-1000A and Alderson Rando phantom were used in this study. Based on the results, it is found clearly that over couch (OC) procedure is riskier than under couch (UC) procedure. The cathode bound area is clearly riskier than anode bound area especially for UC procedure. More doses (at least +1,568 % of safest position) are received by the lens of the eyes for staff standing at the cathode bound area especially the position opposite to the x-ray tube.

  4. Einstein observations of extended galactic X-ray sources

    NASA Technical Reports Server (NTRS)

    Seward, F. D.

    1979-01-01

    Features of the X-ray pictures taken aboard the space observatory are presented. Imaging proportional counter pictures in three broad X-ray energy ranges were obtained. The X-ray spectrum of supernova remnants is described.

  5. An introduction to X-ray astronomy data analysis.

    NASA Astrophysics Data System (ADS)

    Morini, M.

    The following sections are included: * INTRODUCTION * X-RAY COSMIC SOURCES * X-RAY ASTRONOMY DETECTORS * CHARACTERISTIC FEATURES OF X-RAY ASTRONOMY DATA * ENERGY SPECTRA ANALYSIS * TIME VARIABILITY ANALYSIS * IMAGE ANALYSIS * References

  6. X-ray image calibration and its application to clinical orthopedics.

    PubMed

    Schumann, Steffen; Thelen, Benedikt; Ballestra, Steven; Nolte, Lutz-P; Büchler, Philippe; Zheng, Guoyan

    2014-07-01

    X-ray imaging is one of the most commonly used medical imaging modality. Albeit X-ray radiographs provide important clinical information for diagnosis, planning and post-operative follow-up, the challenging interpretation due to its 2D projection characteristics and the unknown magnification factor constrain the full benefit of X-ray imaging. In order to overcome these drawbacks, we proposed here an easy-to-use X-ray calibration object and developed an optimization method to robustly find correspondences between the 3D fiducials of the calibration object and their 2D projections. In this work we present all the details of this outlined concept. Moreover, we demonstrate the potential of using such a method to precisely extract information from calibrated X-ray radiographs for two different orthopedic applications: post-operative acetabular cup implant orientation measurement and 3D vertebral body displacement measurement during preoperative traction tests. In the first application, we have achieved a clinically acceptable accuracy of below 1° for both anteversion and inclination angles, where in the second application an average displacement of 8.06±3.71 mm was measured. The results of both applications indicate the importance of using X-ray calibration in the clinical routine.

  7. Resonant magnetic scattering of polarized soft x rays

    SciTech Connect

    Sacchi, M.; Hague, C.F.; Gullikson, E.M.; Underwood, J.

    1997-04-01

    Magnetic effects on X-ray scattering (Bragg diffraction, specular reflectivity or diffuse scattering) are a well known phenomenon, and they also represent a powerful tool for investigating magnetic materials since it was shown that they are strongly enhanced when the photon energy is tuned across an absorption edge (resonant process). The resonant enhancement of the magnetic scattering has mainly been investigated at high photon energies, in order to match the Bragg law for the typical lattice spacings of crystals. In the soft X-ray range, even larger effects are expected, working for instance at the 2p edges of transition metals of the first row or at the 3d edges of rare earths (300-1500 eV), but the corresponding long wavelengths prevent the use of single crystals. Two approaches have been recently adopted in this energy range: (i) the study of the Bragg diffraction from artificial structures of appropriate 2d spacing; (ii) the analysis of the specular reflectivity, which contains analogous information but has no constraints related to the lattice spacing. Both approaches have their own specific advantages: for instance, working under Bragg conditions provides information about the (magnetic) periodicity in ordered structures, while resonant reflectivity can easily be related to electronic properties and absorption spectra. An important aspect common to all the resonant X-ray scattering techniques is the element selectivity inherent to the fact of working at a specific absorption edge: under these conditions, X-ray scattering becomes in fact a spectroscopy. Results are presented for films of iron and cobalt.

  8. Analysis of x-ray spectrum obtained in electron cyclotron resonance x-ray source

    SciTech Connect

    Baskaran, R.; Selvakumaran, T.S.; Sunil Sunny, C.

    2006-03-15

    The analysis of the x-ray spectrum obtained in electron cyclotron resonance (ECR) x-ray source is carried out. Assuming single-particle motion, the electron acceleration and its final energy are calculated for TE{sub 111} cylindrical cavity field and uniform external dc magnetic field. In the calculation, initial coordinates of 40 000 electrons were uniformly selected over the central plane of the cavity using random number generator. The final energy of each electron when it hits the wall is stored and the electron energy distribution is obtained. Using the general purpose Monte Carlo N-particle transport code version 4A, the geometry of the ECR x-ray source is modeled. The x-ray energy spectrum is calculated for the geometry model and the numerically calculated electron energy distribution. The calculated x-ray spectrum is compared with the experimentally measured x-ray spectrum.

  9. Indus-2 X-ray lithography beamline for X-ray optics and material science applications

    SciTech Connect

    Dhamgaye, V. P. Lodha, G. S.

    2014-04-24

    X-ray lithography is an ideal technique by which high aspect ratio and high spatial resolution micro/nano structures are fabricated using X-rays from synchrotron radiation source. The technique has been used for fabricating optics (X-ray, visible and infrared), sensors and actuators, fluidics and photonics. A beamline for X-ray lithography is operational on Indus-2. The beamline offers wide lithographic window from 1-40keV photon energy and wide beam for producing microstructures in polymers upto size ∼100mm × 100mm. X-ray exposures are possible in air, vacuum and He gas environment. The air based exposures enables the X-ray irradiation of resist for lithography and also irradiation of biological and liquid samples.

  10. Be/X-ray Binary Science for Future X-ray Timing Missions

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2011-01-01

    For future missions, the Be/X-ray binary community needs to clearly define our science priorities for the future to advocate for their inclusion in future missions. In this talk, I will describe current designs for two potential future missions and Be X-ray binary science enabled by these designs. The Large Observatory For X-ray Timing (LOFT) is an X-ray timing mission selected in February 2011 for the assessment phase from the 2010 ESA M3 call for proposals. The Advanced X-ray Timing ARray (AXTAR) is a NASA explorer concept X-ray timing mission. This talk is intended to initiate discussions of our science priorities for the future.

  11. X-ray imaging with compound refractive lens and microfocus x-ray tube

    NASA Astrophysics Data System (ADS)

    Pina, Ladislav; Dudchik, Yury; Jelinek, Vaclav; Sveda, Libor; Marsik, Jiri; Horvath, Martin; Petr, Ondrej

    2008-08-01

    Compound refractive lenses (CRL), consisting of a lot number in-line concave microlenses made of low-Z material were studied. Lenses with focal length 109 mm and 41 mm for 8-keV X-rays, microfocus X-ray tube and X-ray CCD camera were used in experiments. Obtained images show intensity distribution of magnified microfocus X-ray source focal spot. Within the experiments, one lens was also used as an objective lens of the X-ray microscope, where the copper anode X-ray microfocus tube served as a source. Magnified images of gold mesh with 5 microns bars were obtained. Theoretical limits of CRL and experimental results are discussed.

  12. Development of x-ray laminography under an x-ray microscopic condition

    SciTech Connect

    Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio; Yagi, Naoto

    2011-07-15

    An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatial resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.

  13. Bone cartilage imaging with x-ray interferometry using a practical x-ray tube

    NASA Astrophysics Data System (ADS)

    Kido, Kazuhiro; Makifuchi, Chiho; Kiyohara, Junko; Itou, Tsukasa; Honda, Chika; Momose, Atsushi

    2010-04-01

    The purpose of this study was to design an X-ray Talbot-Lau interferometer for the imaging of bone cartilage using a practical X-ray tube and to develop that imaging system for clinical use. Wave-optics simulation was performed to design the interferometer with a practical X-ray tube, a source grating, two X-ray gratings, and an X-ray detector. An imaging system was created based on the results of the simulation. The specifications were as follows: the focal spot size was 0.3 mm of an X-ray tube with a tungsten anode (Toshiba, Tokyo, Japan). The tube voltage was set at 40 kVp with an additive aluminum filter, and the mean energy was 31 keV. The pixel size of the X-ray detector, a Condor 486 (Fairchild Imaging, California, USA), was 15 μm. The second grating was a Ronchi-type grating whose pitch was 5.3 μm. Imaging performance of the system was examined with X-ray doses of 0.5, 3 and 9 mGy so that the bone cartilage of a chicken wing was clearly depicted with X-ray doses of 3 and 9 mGy. This was consistent with the simulation's predictions. The results suggest that X-ray Talbot-Lau interferometry would be a promising tool in detecting soft tissues in the human body such as bone cartilage for the X-ray image diagnosis of rheumatoid arthritis. Further optimization of the system will follow to reduce the X-ray dose for clinical use.

  14. Threshold contrast detail detectability measurement of the fluoroscopic image quality of a dynamic solid-state digital x-ray image detector.

    PubMed

    Davies, A G; Cowen, A R; Kengyelics, S M; Bury, R F; Bruijns, T J

    2001-01-01

    Solid-state digital x-ray imaging detectors of flat-panel construction will play an increasingly important role in future medical imaging facilities. Solid-state detectors that will support both dynamic (including fluoroscopic) and radiographic image recording are under active development. The image quality of an experimental solid-state digital x-ray image detector operating in a continuous fluoroscopy mode has been investigated. The threshold contrast detail detectability (TCDD) technique was used to compare the fluoroscopic imaging performance of an experimental dynamic solid-state digital x-ray image detector with that of a reference image intensifier television (IITV) fluoroscopy system. The reference system incorporated Plumbicon TV. Results were presented as a threshold detection index, or H(T)(A), curves. Measurements were made over a range of mean entrance air kerma (EAK) rates typically used in conventional IITV fluoroscopy. At the upper and mid EAK rate range (440 and 220 nGy/s) the solid-state detector outperformed the reference IITV fluoroscopy system as measured by TCDD performance. At the lowest measured EAK rate (104 nGy/s), the solid-state detector produces slightly inferior TCDD performance compared with the reference system. Although not statistically significant at this EAK rate, the difference will increase as EAK is lowered further. Overall the TCDD results and early clinical experiences support the proposition that a current design of dynamic solid-state detector produces image quality competitive with that of modern IITV fluoroscopy systems. These findings encourage the development of compact and versatile universal x-ray imaging systems based upon solid-state detector technology to support R & F and vascular/interventional applications.

  15. Wire array z-pinch insights for high x-ray power generation

    SciTech Connect

    Sanford, T.W.L.; Mock, R.C.; Nash, T.J.

    1998-08-01

    The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X=ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays.

  16. Wire array z-pinch insights for high x-ray power generation

    SciTech Connect

    Sanford, T.W.L.; Mock, R.C.; Marder, B.M.

    1997-12-31

    The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn and Z. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X-ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays.

  17. High-resolution ab initio Three-dimensional X-ray Diffraction Microscopy

    SciTech Connect

    Chapman, H N; Barty, A; Marchesini, S; Noy, A; Cui, C; Howells, M R; Rosen, R; He, H; Spence, J H; Weierstall, U; Beetz, T; Jacobsen, C; Shapiro, D

    2005-08-19

    Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the 3D diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a non-periodic object. We also construct 2D images of thick objects with infinite depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution using X-ray undulator radiation, and establishes the techniques to be used in atomic-resolution ultrafast imaging at X-ray free-electron laser sources.

  18. Behavior of characteristic X-rays from a partial-transmission-type X-ray target.

    PubMed

    Raza, Hamid Saeed; Kim, Hyun Jin; Ha, Jun Mok; Cho, Sung Oh

    2013-10-01

    The angular distribution of characteristic X-rays using a partial-transmission tungsten target was analyzed. Twenty four tallies were modeled to cover a 360° envelope around the target. The Monte Carlo N-Particle (MCNP5) simulation results revealed that the characteristic X-ray flux is not always isotropic around the target. Rather, the flux mainly depends on the target thickness and the energy of the incident electron beam. A multi-energy photon generator is proposed to emit high-energy characteristic X-rays, where the target acts as a filter for the low-energy characteristic X-rays.

  19. Fabrication of large area X-ray diffraction grating for X-ray phase imaging

    SciTech Connect

    Noda, Daiji; Tokuoka, Atsushi; Katori, Megumi; Minamiyama, Yasuto; Yamashita, Kenji; Nishida, Satoshi; Hattori, Tadashi

    2012-07-31

    X-ray lithography, which uses highly directional synchrotron radiation, is one of the technologies that can be used for fabricating micrometer-sized structures. In X-ray lithography, the accuracy of the fabricated structure depends largely on the accuracy of the X-ray mask. Since X-ray radiation is highly directional, a micro-fabrication technology that produces un-tapered and high aspect ratio highly absorbent structures on a low absorbent membrane is required. Conventionally, a resin material is used as the support membrane for large area X-ray masks. However, resin membranes have the disadvantage that they can sag after several cycles of X-ray exposure due to the heat generated by the X-rays. Therefore, we proposed and used thin carbon wafers for the membrane material because carbon has an extremely small thermal expansion coefficient. We fabricated new carbon membrane X-ray masks, and these results of X-ray lithography demonstrate the superior performance.

  20. Transient x-ray diffraction and its application to materials science and x-ray optics

    SciTech Connect

    Hauer, A.A.; Kopp, R.; Cobble, J.; Kyrala, G.; Springer, R.

    1997-12-01

    Time resolved x-ray diffraction and scattering have been applied to the measurement of a wide variety of physical phenomena from chemical reactions to shock wave physics. Interest in this method has heightened in recent years with the advent of versatile, high power, pulsed x-ray sources utilizing laser plasmas, electron beams and other methods. In this article, we will describe some of the fundamentals involved in time resolved x-ray diffraction, review some of the history of its development, and describe some recent progress in the field. In this article we will emphasize the use of laser-plasmas as the x-ray source for transient diffraction.

  1. Wolter X-Ray Microscope Computed Tomography Ray-Trace Model with Preliminary Simulation Results

    SciTech Connect

    Jackson, J A

    2006-02-27

    It is proposed to build a Wolter X-ray Microscope Computed Tomography System in order to characterize objects to sub-micrometer resolution. Wolter Optics Systems use hyperbolic, elliptical, and/or parabolic mirrors to reflect x-rays in order to focus or magnify an image. Wolter Optics have been used as telescopes and as microscopes. As microscopes they have been used for a number of purposes such as measuring emission x-rays and x-ray fluoresce of thin biological samples. Standard Computed Tomography (CT) Systems use 2D radiographic images, from a series of rotational angles, acquired by passing x-rays through an object to reconstruct a 3D image of the object. The x-ray paths in a Wolter X-ray Microscope will be considerably different than those of a standard CT system. There is little information about the 2D radiographic images that can be expected from such a system. There are questions about the quality, resolution and focusing range of an image created with such a system. It is not known whether characterization information can be obtained from these images and whether these 2D images can be reconstructed to 3D images of the object. A code has been developed to model the 2D radiographic image created by an object in a Wolter X-ray Microscope. This code simply follows the x-ray through the object and optics. There is no modeling at this point of other effects, such as scattering, reflection losses etc. Any object, of appropriate size, can be used in the model code. A series of simulations using a number of different objects was run to study the effects of the optics. The next step will be to use this model to reconstruct an object from the simulated data. Funding for the project ended before this goal could be accomplished. The following documentation includes: (1) background information on current X-ray imaging systems, (2) background on Wolter Optics, (3) description of the Wolter System being used, (4) purpose, limitations and development of the modeling

  2. Atomic Data in X-Ray Astrophysics

    NASA Technical Reports Server (NTRS)

    Brickhouse, N. S.

    2000-01-01

    With the launches of the Chandra X-ray Observatory (CXO) and the X-ray Multimirror Mission (XMM) and the upcoming launch of the Japanese mission ASTRO-E, high resolution X-ray spectroscopy of cosmic sources has begun. Early, deep observations of three stellar coronal sources will provide not only invaluable calibration data, but will also give us benchmarks for the atomic data under collisional equilibrium conditions. Analysis of the Chandra X-ray Observatory data, and data from other telescopes taken simultaneously, for these stars is ongoing as part of the Emission Line Project. Goals of the Emission Line Project are: (1) to determine and verify accurate and robust diagnostics and (2) to identify and prioritize issues in fundamental spectroscopy which will require further theoretical and/or laboratory work. The Astrophysical Plasma Emission Database will be described in some detail, as it is introducing standardization and flexibility into X-ray spectral modeling. Spectral models of X-ray astrophysical plasmas can be generally classified as dominated by either collisional ionization or by X-ray photoionization. While the atomic data needs for spectral models under these two types of ionization are significantly different, there axe overlapping data needs, as I will describe. Early results from the Emission Line Project benchmarks are providing an invaluable starting place, but continuing work to improve the accuracy and completeness of atomic data is needed. Additionally, we consider the possibility that some sources will require that both collisional ionization and photoionization be taken into account, or that time-dependent ionization be considered. Thus plasma spectral models of general use need to be computed over a wide range of physical conditions.

  3. Handbook of X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Arnaud, Keith A. (Editor); Smith, Randall K.; Siemiginowska, Aneta

    2011-01-01

    X-ray astronomy was born in the aftermath of World War II as military rockets were repurposed to lift radiation detectors above the atmosphere for a few minutes at a time. These early flights detected and studied X-ray emission from the Solar corona. The first sources beyond the Solar System were detected during a rocket flight in 1962 by a team headed by Riccardo Giaccom at American Science and Engineering, a company founded by physicists from MIT. The rocket used Geiger counters with a system designed to reduce non-X-ray backgrounds and collimators limiting the region of sky seen by the counters. As the rocket spun, the field of view (FOV) happened to pass over what was later found to be the brightest non-Solar X-ray source; later designated See X-1. It also detected a uniform background glow which could not be resolved into individual sources. A follow-up campaign using X-ray detectors with better spatial resolution and optical telescopes identified See X-1 as an interacting binary with a compact (neutron star) primary. This success led to further suborbital rocket flights by a number of groups. More X-ray binaries were discovered, as well as X-ray emission from supernova remnants, the radio galaxies M87 and Cygnus-A, and the Coma cluster. Detectors were improved and Geiger counters were replaced by proportional counters, which provided information about energy spectra of the sources. A constant challenge was determining precise positions of sources as only collimators were available.

  4. [Digital radiography und fluoroscopy. Basics of technology, imaging properties and applications].

    PubMed

    Loose, R; Busch, H P; Wucherer, M

    2005-08-01

    For 110 years, x-rays and special x-ray films have been used in medical diagnostics. New developments in the field of x-ray techniques, and especially new computer applications, have led to new imaging techniques which have substantially expanded the spectrum of radiological examinations. In spite of significant technological and medical advances in the field of MRI and multidetector-CT, radiographic images of the lungs, skeleton and organs still comprise up to 80% of the routine radiological workload. The increasing availability of digital detectors has led to the continual replacement of conventional film/screen systems. The inclusion of digital mammography was delayed due to the higher requirements for spatial resolution. For about 2 years, dynamic flat panel detectors have started to replace the image intensifier which has been used in fluoroscopy for 40 years.

  5. MO-G-18A-01: Radiation Dose Reducing Strategies in CT, Fluoroscopy and Radiography

    SciTech Connect

    Mahesh, M; Gingold, E; Jones, A

    2014-06-15

    Advances in medical x-ray imaging have provided significant benefits to patient care. According to NCRP 160, there are more than 400 million x-ray procedures performed annually in the United States alone that contributes to nearly half of all the radiation exposure to the US population. Similar growth trends in medical x-ray imaging are observed worldwide. Apparent increase in number of medical x-ray imaging procedures, new protocols and the associated radiation dose and risk has drawn considerable attention. This has led to a number of technological innovations such as tube current modulation, iterative reconstruction algorithms, dose alerts, dose displays, flat panel digital detectors, high efficient digital detectors, storage phosphor radiography, variable filters, etc. that are enabling users to acquire medical x-ray images at a much lower radiation dose. Along with these, there are number of radiation dose optimization strategies that users can adapt to effectively lower radiation dose in medical x-ray procedures. The main objectives of this SAM course are to provide information and how to implement the various radiation dose optimization strategies in CT, Fluoroscopy and Radiography. Learning Objectives: To update impact of technological advances on dose optimization in medical imaging. To identify radiation optimization strategies in computed tomography. To describe strategies for configuring fluoroscopic equipment that yields optimal images at reasonable radiation dose. To assess ways to configure digital radiography systems and recommend ways to improve image quality at optimal dose.

  6. A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images

    SciTech Connect

    Panayiotou, Maria King, Andrew P.; Housden, R. James; Ma, YingLiang; Rhode, Kawal S.; Cooklin, Michael; O'Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo

    2014-07-15

    Purpose: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. Methods: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. Results: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of√(5)0, √(1)0, √(8), √(6), √(5), √(2), and √(1) to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √(2), representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. Conclusions: The proposed

  7. X-Ray Calorimeter Arrays for Astrophysics

    NASA Technical Reports Server (NTRS)

    Kilbourne, Caroline A.

    2009-01-01

    High-resolution x-ray spectroscopy is a powerful tool for studying the evolving universe. The grating spectrometers on the XMM and Chandra satellites started a new era in x-ray astronomy, but there remains a need for instrumentation that can provide higher spectral resolution with high throughput in the Fe-K band (around 6 keV) and can enable imaging spectroscopy of extended sources, such as supernova remnants and galaxy clusters. The instrumentation needed is a broad-band imaging spectrometer - basically an x-ray camera that can distinguish tens of thousands of x-ray colors. The potential benefits to astrophysics of using a low-temperature calorimeter to determine the energy of an incident x-ray photon via measurement of a small change in temperature was first articulated by S. H. Moseley over two decades ago. In the time since, technological progress has been steady, though full realization in an orbiting x-ray telescope is still awaited. A low-temperature calorimeter can be characterized by the type of thermometer it uses, and three types presently dominate the field. The first two types are temperature-sensitive resistors - semiconductors in the metal-insulator transition and superconductors operated in the superconducting-normal transition. The third type uses a paramagnetic thermometer. These types can be considered the three generations of x-ray calorimeters; by now each has demonstrated a resolving power of 2000 at 6 keV, but only a semiconductor calorimeter system has been developed to spaceflight readiness. The Soft X-ray Spectrometer on Astro-H, expected to launch in 2013, will use an array of silicon thermistors with I-IgTe x-ray absorbers that will operate at 50 mK. Both the semiconductor and superconductor calorimeters have been implemented in small arrays, kilo-pixel arrays of the superconducting calorimeters are just now being produced, and it is anticipated that much larger arrays will require the non-dissipative advantage of magnetic thermometers.

  8. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  9. Globular cluster X-ray sources

    NASA Astrophysics Data System (ADS)

    Pooley, D.

    We know from observations that globular clusters are very efficient catalysts in forming unusual binary systems, such as low-mass X-ray binaries (LMXBs), cataclysmic variables (CVs), and millisecond pulsars (MSPs), with formation rates per unit mass exceeding those in the Galactic disk by orders of magnitude. The high stellar densities in globular clusters trigger various dynamical interactions: exchange encounters, direct collisions, destruction of binaries, and tidal capture. This binary population is, in turn, critical to the stabilization of globular clusters against gravitational collapse; the long-term stability of a cluster is thought to depend on tapping into the gravitational binding energy of such close binaries. I will present an overview of the current state of globular cluster X-ray observations, as well as our work on deep Chandra observations of M4, where we reach some of the lowest X-ray luminosities in any globular cluster (comparable to the deep observations of 47 Tuc and NGC 6397). One of M4 X-ray sources previously classified as a white dwarf binary is likely a neutron star binary, and another X-ray source is a sub-subgiant, the nature of which is still unclear. skip=3pt

  10. Visualization of x-ray backscatter data

    SciTech Connect

    Greenawald, E.C.; Ham, Y.S.; Poranski, C.F. Jr.

    1993-12-31

    Of the several processes which occur when x-rays interact with matter, Compton scattering is dominant in the range of energies commonly used in industrial radiography. The Compton interaction between an x-ray photon and a free or outer shell electron causes the electron to recoil and the photon to be propagated in a new direction with a reduced energy. Regardless of the incident beam energy, some photons are always scattered in the backwards direction. The potential for determining material properties by the detection of x-ray backscatter has been recognized for years. Although work in this area has been eclipsed by the rapid development of computerized tomography (CT), a variety of industrial backscatter imaging techniques and applications have been demonstrated. Backscatter inspection is unique among x-ray methods in its applicability with access to only one side of the object. The authors are currently developing the application of x-ray backscatter tomography (XBT) to the inspection of steel-reinforced rubber sonar domes on US Navy vessels. In this paper, the authors discuss the visualization methods they use to interpret the XBT data. They present images which illustrate the capability of XBT as applied to sonar domes and a variety of other materials and objects. They also demonstrate and discuss the use of several data visualization software products.

  11. Optics for coherent X-ray applications.

    PubMed

    Yabashi, Makina; Tono, Kensuke; Mimura, Hidekazu; Matsuyama, Satoshi; Yamauchi, Kazuto; Tanaka, Takashi; Tanaka, Hitoshi; Tamasaku, Kenji; Ohashi, Haruhiko; Goto, Shunji; Ishikawa, Tetsuya

    2014-09-01

    Developments of X-ray optics for full utilization of diffraction-limited storage rings (DLSRs) are presented. The expected performance of DLSRs is introduced using the design parameters of SPring-8 II. To develop optical elements applicable to manipulation of coherent X-rays, advanced technologies on precise processing and metrology were invented. With propagation-based coherent X-rays at the 1 km beamline of SPring-8, a beryllium window fabricated with the physical-vapour-deposition method was found to have ideal speckle-free properties. The elastic emission machining method was utilized for developing reflective mirrors without distortion of the wavefronts. The method was further applied to production of diffraction-limited focusing mirrors generating the smallest spot size in the sub-10 nm regime. To enable production of ultra-intense nanobeams at DLSRs, a low-vibration cooling system for a high-heat-load monochromator and advanced diagnostic systems to characterize X-ray beam properties precisely were developed. Finally, new experimental schemes for combinative nano-analysis and spectroscopy realised with novel X-ray optics are discussed.

  12. Oscillations During Thermonuclear X-ray Bursts

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod E.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290Hz) has, been claimed.

  13. Ultrafast X-Ray Coherent Control

    SciTech Connect

    Reis, David

    2009-05-01

    This main purpose of this grant was to develop the nascent eld of ultrafast x-ray science using accelerator-based sources, and originally developed from an idea that a laser could modulate the di racting properties of a x-ray di racting crystal on a fast enough time scale to switch out in time a shorter slice from the already short x-ray pulses from a synchrotron. The research was carried out primarily at the Advanced Photon Source (APS) sector 7 at Argonne National Laboratory and the Sub-Picosecond Pulse Source (SPPS) at SLAC; in anticipation of the Linac Coherent Light Source (LCLS) x-ray free electron laser that became operational in 2009 at SLAC (all National User Facilities operated by BES). The research centered on the generation, control and measurement of atomic-scale dynamics in atomic, molecular optical and condensed matter systems with temporal and spatial resolution . It helped develop the ultrafast physics, techniques and scienti c case for using the unprecedented characteristics of the LCLS. The project has been very successful with results have been disseminated widely and in top journals, have been well cited in the eld, and have laid the foundation for many experiments being performed on the LCLS, the world's rst hard x-ray free electron laser.

  14. Polarisation modulation in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ingram, Adam; Maccarone, Thomas

    2016-07-01

    X-ray polarimetry promises to provide a powerful new lever arm for studying accretion onto black holes with the next generation of X-ray telescopes. I will discuss how polarisation can be used to help constrain the physical origin of quasi-periodic oscillations (QPOs) observed in the X-ray light curves of accreting black holes. QPOs may be signatures of the frame dragging effect: in General Relativity, a spinning black hole twists up the surrounding space-time, causing vertical precession of nearby orbits. In the truncated disc / precessing inner flow model, the entire inner accretion flow precesses as a solid body causing a modulation in the X-ray flux through solid angle and Doppler effects. This model also predicts the observed polarisation of the X-ray signal to vary quasi-periodically. I will summarise our work to model the polarisation signal from a precessing accretion flow, starting with simple assumptions about the emission mechanism but taking General Relativity fully into account. We find that it should be possible to measure the predicted modulation in polarisation degree for a reasonable region of parameter space with a polarimeter capable of detecting ~60 counts per second from a bright black hole binary. I will also show that sensitivity can be greatly improved by correlating the signal with a high count rate reference band signal.

  15. Thin Shell, Segmented X-Ray Mirrors

    NASA Technical Reports Server (NTRS)

    Petre, Robert

    2010-01-01

    Thin foil mirrors were introduced as a means of achieving high throughput in an X-ray astronomical imaging system in applications for which high angular resolution were not necessary. Since their introduction, their high filling factor, modest mass, relative ease of construction, and modest cost have led to their use in numerous X-ray observatories, including the Broad Band X-ray Telescope, ASCA, and Suzaku. The introduction of key innovations, including epoxy replicated surfaces, multilayer coatings, and glass mirror substrates, has led to performance improvements, and in their becoming widely used for X-ray astronomical imaging at energies above 10 keV. The use of glass substrates has also led to substantial improvement in angular resolution, and thus their incorporation into the NASA concept for the International X-ray Observatory with a planned 3 in diameter aperture. This paper traces the development of foil mirrors from their inception in the 1970's through their current and anticipated future applications.

  16. X-ray lithography using holographic images

    DOEpatents

    Howells, M.S.; Jacobsen, C.

    1997-03-18

    Methods for forming X-ray images having 0.25 {micro}m minimum line widths on X-ray sensitive material are presented. A holographic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required. 15 figs.

  17. X-Ray Surveyor Mission Concept

    NASA Astrophysics Data System (ADS)

    Gaskin, Jessica

    2015-10-01

    An initial concept study for the X-ray Surveyor mission was carried-out by the Advanced Concept Office at Marshall Space Flight Center (MSFC), with a strawman payload and related requirements that were provided by an Informal Mission Concept Team, comprised of MSFC and Smithsonian Astrophysics Observatory (SAO) scientists plus a diverse cross-section of the X-ray community. The study included a detailed assessment of the requirements, a preliminary design, a mission analysis, and a preliminary cost estimate. The X-ray Surveyor strawman payload is comprised of a high-resolution mirror assembly and an instrument set, which may include an X-ray microcalorimeter, a high-definition imager, and a dispersive grating spectrometer and its readout. The mirror assembly will consist of highly nested, thin, grazing-incidence mirrors, for which a number of technical approaches are currently under development—including adjustable X-ray optics, differential deposition, and new polishing techniques applied to a variety of substrates. This study benefits from previous studies of large missions carried out over the past two decades, such as Con-X, AXSIO and IXO, and in most areas, points to mission requirements no more stringent than those of Chandra.

  18. Radiographic X-Ray Pulse Jitter

    SciTech Connect

    Mitton, C. V., Good, D. E., Henderson, D. J., Hogge, K. W.

    2011-01-15

    The Dual Beam Radiographic Facility consists of two identical radiographic sources. Major components of the machines are: Marx generator, water-filled pulse-forming line (PFL), water-filled coaxial transmission line, three-cell inductive voltage adder, and rod-pinch diode. The diode pulse has the following electrical specifications: 2.25-MV, 60-kA, 60-ns. Each source has the following x-ray parameters: 1-mm-diameter spot size, 4-rad at 1 m, 50-ns full width half max. The x-ray pulse is measured with PIN diode detectors. The sources were developed to produce high resolution images on single-shot, high-value experiments. For this application it is desirable to maintain a high level of reproducibility in source output. X-ray pulse jitter is a key metric for analysis of reproducibility. We will give measurements of x-ray jitter for each machine. It is expected that x-ray pulse jitter is predominantly due to PFL switch jitter, and therefore a correlation of the two will be discussed.

  19. X-ray lasing - The diagnostics

    SciTech Connect

    Not Available

    1985-11-01

    High-sensitivity time-resolving x-ray spectrometers were developed for the Novette x-ray laser experiments to distinguish and characterize those x-rays produced by laser activity amidst all the other background radiation. In the microchannel-plate grazing-incidence spectrometer (MCPIGS) x-rays are dispersed according to wavelength by a concave grating into a curved microchannel plate, and the amplified image is mapped flat for photographic recording. Target radiation is detected between 12.5 and 27 nm with 250 ps temporal resolution, high spectral resolution (lambda/Delta lambda = 1800), and a line-radiation detection threshold of 6 x 10 to the -7th J/sr. The transmission-grating streak spectrometer (TGSS) produces an image of the x-ray laser output (with an ellipsoidal mirror) that is separated horizontally into its constituent wavelengths (with a transmission grating) and resolved vertically in time (with a streak caemra). The TGSS has a time resolution of about 40 ps, a spectral resolution of about 0.1 nm, and a collection solid angle of about 1.2 x 10 to the -4th sr.

  20. Imaging of x rays for magnetospheric investigations

    SciTech Connect

    Imhof, W.L.; Voss, H.D.; Datlowe, D.W. . Space Sciences Lab.)

    1994-02-01

    X-ray imagers can provide large-scale maps of bremsstrahlung x rays produced by electron precipitation into the atmosphere. Complete day and night coverage is obtained and the electron energy spectra at each position in space can be derived from the measured x-ray energy spectra. Early x-ray imagers were limited in field of view and to one map for each pass over the emitting regions. The Magnetospheric Atmospheric X-ray Imaging Experiment, launched on a TIROS satellite, makes time-space mappings by scanning a 16-pixel pinhole camera. The data distinguish intensity variations of a fixed auroral feature from motion of a steadily radiating feature. However, the spatial deconvolution is complex and features stay in the field of view for only [approximately]10 min. These problems will be resolved by a high-altitude ([approximately]9 R[sub e]) imaging spectrometer PIXIE on the ISTP/GGS Polar Satellite to be launched in 1994. PIXIE's position-sensitive proportional counter will continuously image the entire auroral zone for periods of hours.

  1. Imaging of x rays for magnetospheric investigations

    NASA Astrophysics Data System (ADS)

    Imhof, William L.; Voss, Henry D.; Datlowe, Dayton W.

    1994-02-01

    X-ray imagers can provide large-scale maps of bremsstrahlung x rays produced by electron precipitation into the atmosphere. Complete day and night coverage is obtained and the electron energy spectra at each position in space can be derived from the measured x-ray energy spectra. Early x-ray imagers were limited in field of view and to one map for each pass over the emitting regions. The Magnetospheric Atmospheric X-ray Imaging Experiment, launched on a TIROS satellite, makes time-space mappings by scanning a 16-pixel pinhole camera. The data distinguish intensity variations of a fixed auroral feature from motion of a steadily radiating feature. However, the spatial deconvolution is complex and features stay in the field of view for only approximately 10 min. These problems will be resolved by a high- altitude (approximately 9 Re) imaging spectrometer PIXIE on the ISTP/GGS Polar Satellite to be launched in 1994. PIXIE's position-sensitive proportional counter will continuously image the entire auroral zone for periods of hours.

  2. X-ray Pinhole Camera Measurements

    SciTech Connect

    Nelson, D. S.; Berninger, M. J.; Flores, P. A.; Good, D. E.; Henderson, D. J.; Hogge, K. W.; Huber, S. R.; Lutz, S. S.; Mitchell, S. E.; Howe, R. A.; Mitton, C. V.; Molina, I.; Bozman, D. R.; Cordova, S. R.; Mitchell, D. R.; Oliver, B. V.; Ormond, E. C.

    2013-07-01

    The development of the rod pinch diode [1] has led to high-resolution radiography for dynamic events such as explosive tests. Rod pinch diodes use a small diameter anode rod, which extends through the aperture of a cathode plate. Electrons borne off the aperture surface can self-insulate and pinch onto the tip of the rod, creating an intense, small x-ray source (Primary Pinch). This source has been utilized as the main diagnostic on numerous experiments that include high-value, single-shot events. In such applications there is an emphasis on machine reliability, x-ray reproducibility, and x-ray quality [2]. In tests with the baseline rod pinch diode, we have observed that an additional pinch (Secondary Pinch) occurs at the interface near the anode rod and the rod holder. This suggests that stray electrons exist that are not associated with the Primary Pinch. In this paper we present measurements on both pinches using an x-ray pinhole camera. The camera is placed downstream of the Primary Pinch at an angle of 60° with respect to the diode centerline. This diagnostic will be employed to diagnose x-ray reproducibility and quality. In addition, we will investigate the performance of hybrid diodes relating to the formation of the Primary and Secondary Pinches.

  3. The Chandra X-Ray Observatory

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.

    2013-01-01

    The Chandra X-ray Observatory, the third of NASA's four Great Observatories and its flagship mission for X-ray astronomy, was launched by NASA's Space Shuttle Columbia on July 23, 1999. The first X-ray sources were observed on August 12, 1999. The brightest of these sources named Leon X-1 in honor of Chandra's Telescope Scientist who played the leading role in establishing the key to Chandra's great advance in angular resolution. Over the past years, the Observatory's ability to provide sub-arc second X-ray images and high resolution spectra has established it as one of the most versatile and powerful tools for astrophysical research in the 21st century. Chandra explores the high-energy regions of the universe, observing X-ray sources with fluxes ranging over more than 10 orders of magnitude. The longevity of Chandra also provides a long observing baseline enabling temporal studies over time-scales of years. I will discuss how the Observatory works, the current operational status, and scientific highlights covering a variety of objects from stars with nearby planets that impact the stellar activity to the deepest Chandra surveys.

  4. Calibration of X-Ray Observatories

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; L'Dell, Stephen L.

    2011-01-01

    Accurate calibration of x-ray observatories has proved an elusive goal. Inaccuracies and inconsistencies amongst on-ground measurements, differences between on-ground and in-space performance, in-space performance changes, and the absence of cosmic calibration standards whose physics we truly understand have precluded absolute calibration better than several percent and relative spectral calibration better than a few percent. The philosophy "the model is the calibration" relies upon a complete high-fidelity model of performance and an accurate verification and calibration of this model. As high-resolution x-ray spectroscopy begins to play a more important role in astrophysics, additional issues in accurately calibrating at high spectral resolution become more evident. Here we review the challenges of accurately calibrating the absolute and relative response of x-ray observatories. On-ground x-ray testing by itself is unlikely to achieve a high-accuracy calibration of in-space performance, especially when the performance changes with time. Nonetheless, it remains an essential tool in verifying functionality and in characterizing and verifying the performance model. In the absence of verified cosmic calibration sources, we also discuss the notion of an artificial, in-space x-ray calibration standard. 6th

  5. Optics for coherent X-ray applications

    PubMed Central

    Yabashi, Makina; Tono, Kensuke; Mimura, Hidekazu; Matsuyama, Satoshi; Yamauchi, Kazuto; Tanaka, Takashi; Tanaka, Hitoshi; Tamasaku, Kenji; Ohashi, Haruhiko; Goto, Shunji; Ishikawa, Tetsuya

    2014-01-01

    Developments of X-ray optics for full utilization of diffraction-limited storage rings (DLSRs) are presented. The expected performance of DLSRs is introduced using the design parameters of SPring-8 II. To develop optical elements applicable to manipulation of coherent X-rays, advanced technologies on precise processing and metrology were invented. With propagation-based coherent X-rays at the 1 km beamline of SPring-8, a beryllium window fabricated with the physical-vapour-deposition method was found to have ideal speckle-free properties. The elastic emission machining method was utilized for developing reflective mirrors without distortion of the wavefronts. The method was further applied to production of diffraction-limited focusing mirrors generating the smallest spot size in the sub-10 nm regime. To enable production of ultra-intense nanobeams at DLSRs, a low-vibration cooling system for a high-heat-load monochromator and advanced diagnostic systems to characterize X-ray beam properties precisely were developed. Finally, new experimental schemes for combinative nano-analysis and spectroscopy realised with novel X-ray optics are discussed. PMID:25177986

  6. X-ray irradiation of yeast cells

    NASA Astrophysics Data System (ADS)

    Masini, Alessandra; Batani, Dimitri; Previdi, Fabio; Conti, Aldo; Pisani, Francesca; Botto, Cesare; Bortolotto, Fulvia; Torsiello, Flavia; Turcu, I. C. Edmond; Allott, Ric M.; Lisi, Nicola; Milani, Marziale; Costato, Michele; Pozzi, Achille; Koenig, Michel

    1997-10-01

    Saccharomyces Cerevisiae yeast cells were irradiated using the soft X-ray laser-plasma source at Rutherford Laboratory. The aim was to produce a selective damage of enzyme metabolic activity at the wall and membrane level (responsible for fermentation) without interfering with respiration (taking place in mitochondria) and with nuclear and DNA activity. The source was calibrated by PIN diodes and X-ray spectrometers. Teflon stripes were chosen as targets for the UV laser, emitting X-rays at about 0.9 keV, characterized by a very large decay exponent in biological matter. X-ray doses to the different cell compartments were calculated following a Lambert-Bouguet-Beer law. After irradiation, the selective damage to metabolic activity at the membrane level was measured by monitoring CO2 production with pressure silicon detectors. Preliminary results gave evidence of pressure reduction for irradiated samples and non-linear response to doses. Also metabolic oscillations were evidenced in cell suspensions and it was shown that X-ray irradiation changed the oscillation frequency.

  7. X-ray echo spectroscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Shvyd'ko, Yuri V.

    2016-09-01

    X-ray echo spectroscopy, a counterpart of neutron spin-echo, was recently introduced [1] to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a point-like x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x-rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-meV and 0.02-meV ultra-high-resolution IXS applications (resolving power > 10^8) with broadband 5-13 meV dispersing systems will be presented featuring more than 1000-fold signal enhancement. The technique is general, applicable in different photon frequency domains. [1.] Yu. Shvyd'ko, Phys. Rev. Lett. 116, accepted (2016), arXiv:1511.01526.

  8. X-ray lithography using holographic images

    DOEpatents

    Howells, Malcolm S.; Jacobsen, Chris

    1997-01-01

    Methods for forming X-ray images having 0.25 .mu.m minimum line widths on X-ray sensitive material are presented. A holgraphic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required.

  9. Design, analysis and testing of x-ray tube for next generation x-ray machines

    NASA Astrophysics Data System (ADS)

    Sanganal, Santoshakumar; Rao Ratnala, Srinivas; Shivakumar Gouda, P. S.

    2016-09-01

    A conceptual design of x-ray metal tube frame assembly is done to establish the technical feasibility and characterize the performance of a base design of x-ray metal tube frame assembly to meet the experimental critical to qualities (CTQ's) of x-ray tube at 72 kW for 20 seconds. Experimental test configuration with linear variable differential transformers (LVDT's) & thermo-couples is set to study the thermal prediction of x-ray tube with model results. Graphs of temperature versus time and deflection versus time shows curve shape magnitudes within 5% and 1%. A thermal - structural analysis is considered in analyzing the thermal - structural behavior in x-ray metal tube by considering worst protocol as 3.2 kW in steady state condition and 14.4 kW in transient state condition for 30 seconds. This analysis is done by doing a conceptual design of x-ray metal tube frame assembly with major modifications in frame and electron collector based on thermal - structural results. 3D modelling of x-ray metal tube frame assembly is done in Creo parametric 2.0 CAD software and analysis is done in ANSYS 16.1 simulation software. FEA results of conceptual design are in good agreement with CTQ's results of x-ray tube at 72 kW for 20 seconds.

  10. Characteristic X-ray Generator Utilizing Angle Dependence of Bremsstrahlung X-ray Distribution

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Inoue, Takashi; Ogawa, Akira; Sato, Shigehiro; Takayama, Kazuyoshi; Onagawa, Jun

    2006-04-01

    This generator consists of the following components: a constant high-voltage power supply, a filament power supply, a turbomolecular pump, and an X-ray tube. The X-ray tube is a demountable diode which is connected to the turbomolecular pump and consists of the following major devices: a molybdenum rod target, a tungsten hairpin cathode (filament), a focusing (Wehnelt) electrode, a polyethylene terephthalate X-ray window 0.25 mm in thickness, and a stainless-steel tube body. In the X-ray tube, the positive high voltage is applied to the anode (target) electrode, and the cathode is connected to the tube body (ground potential). In this experiment, the tube voltage applied was from 22 to 36 kV, and the tube current was regulated to within 100 μA by the filament temperature. The exposure time is controlled in order to obtain optimum X-ray intensity. The electron beams from the cathode are converged to the target by the focusing electrode, and clean K-series characteristic X-rays are produced through the focusing electrode without using a filter. The X-ray intensity was 26.6 μGy/s at 1.0 m from the X-ray source with a tube voltage of 30 kV and a tube current of 100 μA, and quasi-monochromatic radiography was performed using a computed radiography system.

  11. The superslow pulsation X-ray pulsars in high mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Wang, Wei

    2013-03-01

    There exists a special class of X-ray pulsars that exhibit very slow pulsation of P spin > 1000 s in the high mass X-ray binaries (HMXBs). We have studied the temporal and spectral properties of these superslow pulsation neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term monitoring observations find spin period evolution of two sources: spin-down trend for 4U 2206+54 (P spin ~ 5560 s with Ṗ spin ~ 4.9 × 10-7 s s-1) and long-term spin-up trend for 2S 0114+65 (P spin ~ 9600 s with Ṗ spin ~ -1 × 10-6 s s-1) in the last 20 years. A Be X-ray transient, SXP 1062 (P spin ~ 1062 s), also showed a fast spin-down rate of Ṗ spin ~ 3 × 10-6 s s-1 during an outburst. These superslow pulsation neutron stars cannot be produced in the standard X-ray binary evolution model unless the neutron star has a much stronger surface magnetic field (B > 1014 G). The physical origin of the superslow spin period is still unclear. The possible origin and evolution channels of the superslow pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could be younger X-ray binary systems, still in the fast evolution phase preceding the final equilibrium state. Alternatively, they could be a new class of neutron star system - accreting magnetars.

  12. X-Ray Data from the X-Ray Data Booklet Online

    DOE Data Explorer

    Thompson, Albert C.; Attwood, David T.; Gullikson, Eric M.; Howells, Malcolm R.; Kortright, Jeffrey B.; Robinson, Arthur L.; Underwood, James H.; Kim, Kwang-Je; Kirz, Janos; Lindau, Ingolf; Pianetta, Piero; Winick, Herman; Williams, Gwyn P.; Scofield, James H.

    The original X-Ray Data Booklet, published in 1985, became a classic reference source. The online version has been significantly revised and updated to reflect today's science. Hundreds of pages of authoritative data provide the x-ray properties of elements, information on synchrotron radiation, scattering processes, optics and detectors, and other related calculations, formulas, and data tables.

  13. Improvement of X-ray Imaging Crystal Spectrometers for KSTAR

    NASA Astrophysics Data System (ADS)

    Lee, Sang Gon; Bitter, M.; Nam, U. W.; Moon, M. K.

    2005-10-01

    The X-ray imaging crystal spectrometers for the KSTAR tokamak will provide spatially and temporally resolved spectra of the resonance line of helium-like argon (or krypton) and the associated satellites from multiple lines of sight parallel and perpendicular to the horizontal mid-plane for measurements of the profiles of the ion and electron temperatures, plasma rotation velocity, and ionization equilibrium. The spectrometers are consisted of a spherically bent quartz crystal and a 10 cm x 30 cm large 2D position-sensitive multi-wire proportional counter. A 2D detector with delay-line readout and supporting electronics has been fabricated and tested on the NSTX tokamak at PPPL. Position resolution and count rate capability of the 2D detector are still need to be improved to meet the requirements. Hence, a segmented version of the 2D detector is under development to satisfy the requirements. The experimental results from the improved 2D detector will be presented.

  14. Two-Photon X-Ray Diffraction.

    PubMed

    Stöhr, J

    2017-01-13

    The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a "source," consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focussed beyond the diffraction limit. The case of cloned x-ray biphotons is compared to and distinguished from the much studied case of entangled optical biphotons.

  15. Explorer Program: X-ray Timing Explorer

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This booklet describes the X-ray Timing Explorer (XTE), one in a series of Explorer missions administered by the National Aeronautics and Space Administration's (NASA) Office of Space Science and managed by the NASA Goddard Space Flight Center (GSFC). The X-ray astronomy observatory is scheduled for launch into low-Earth orbit by Delta 2 expendable launch vehicle in late summer of 1995. The mission is expected to operate for at least 2 years and will carry out in-depth timing and spectral studies of the X-ray sources in the 2 to 200 kilo-electron Volt (keV) range. XTE is intended to study the temporal and broad-band spectral phenomena associated with stellar and galactic systems containing compact objects, including neutron stars, white dwarfs, and black holes.

  16. Instrumentation for X-ray Astronomy

    NASA Technical Reports Server (NTRS)

    Ramsey, Brian D.; Austin, Robert A.; Decher, Rudolf

    1994-01-01

    Less than five decades ago, the first X-ray observations of the sky were made using simple devices such as film and geiger counters with crude collimators. These instruments were carried aloft by sounding rockets and made observations lasting only a few minutes at most. Today, orbiting observatories, utilizing high-resolution charged coupled devices (CCD's) at the focus of arc sec optics, have lifetimes measured in years. To maintain the pace of discovery in X-ray astronomy, detectors must continue to evolve into devices of ever increasing sensitivity and sophistication. Further progress depends upon a host of technologies: grazing incidence optics, proportional counters, semiconductors, calorimeters, etc. In this article we present a brief qualitative overview of these technologies and of the principles behind them, as well as some examples of how they are employed in scientific missions for X-ray observations at energies up to 100 keV.

  17. Combined microstructure x-ray optics

    SciTech Connect

    Barbee, T.W. Jr.

    1989-02-01

    Multilayers are man-made microstructures which vary in depth and are now of sufficient quality to be used as x-ray, soft x-ray and extreme ultraviolet optics. Gratings are man-made in plane microstructures which have been used as optic elements for most of this century. Joining of these two optical microstructures to form combined microstructure optical microstructures to form combined microstructure optical elements has the potential for greatly enhancing both the throughput and the resolution attainable in these spectral ranges. The characteristics of these new optic elements will be presented and compared to experiment with emphasis on the unique properties of these combined microstructures. These results reported are general in nature and not limited to the soft x-ray or extreme ultraviolet spectral domains and also apply to neutrons. 19 refs., 7 figs., 4 tabs.

  18. Apollo galactic X-ray astronomy observations

    NASA Technical Reports Server (NTRS)

    Adler, I.; Trombka, J.; Schmadebeck, R.; Gorenstein, P.; Bjorkholm, P.

    1971-01-01

    The galactic X-ray observations are a detailed study of the temporal behavior of pulsating X-ray sources. NASA's first X-ray astronomy satellite Uhuru (Explorer 42) has recently discovered fast time variability of pulsations in the output from several sources. The variability occurs on a time scale of minutes, seconds, or less, implying that the emitting regions are very small in size, much smaller than the sun, although they are emitting about a thousand times more power. Fast time variability may provide the clue that is needed to understand the mechanisms which drive pulsating sources. The Apollo observations record the emission from several objects continuously for a period of about an hour. The spacecraft can be pointed at the source for the entire time. On the other hand, Uhuru can observe only for about a minute or two per sighting. Consequently, Apollo has the capability for determining whether periodicities exist in the 10-1000 second range.

  19. X-ray atlas of rheumatic diseases

    SciTech Connect

    Dihlmann, W.

    1986-01-01

    This atlas comprises instructive X-rays of the various inflammatory rheumatic joint diseases in all stages at the extremities and the spinal column. In addition, the complex pattern of the wide range of arthroses, also known as degenerative rheumatic disease is included. Besides the instructive pointers to X-ray diagnosis, the book is also a guide to differential diagnosis. Hence, this book is actually an X-ray atlas of joint diseases in general. Selected Contents: Introduction: What Does ''Rheumatism'' Actually Mean./Radiographic Methodology in Rheumatic Diseases of the Locomotor System/The Mosaic of Arthritis/Adult Rheumatoid Arthritis/Seronegative Spondylarthritis/Classic Collagen Diseases/Enthesiopathies/Gout-Pseudogout

  20. Digital Speckle X-Ray Flash Photography

    NASA Astrophysics Data System (ADS)

    Grantham, S. G.; Proud, W. G.

    2002-07-01

    The new technique of digital speckle X-ray flash photography (DSXFP), which has been successfully applied to polyester and cement specimens, is being further developed and used to study materials in ballistic situations in a way not previously possible. The technique involves seeding the specimen with a lead layer and then taking flash X-ray images before and during an impact event. Digital cross-correlation can then be used to make measurements of the internal displacements occurring throughout the specimen. Using a stereoscopic geometry the out of plane displacements can also be determined and a full 3-dimensional displacement map constructed. In this paper these two powerful and complementary techniques of flash X-rays and DSXFP are used to study the ballistic response of a borosilicate sample to produce information that other techniques are unable to provide.