Direct Imaging System Research Articles

Orbotech delivers 500th laser direct imaging system

Orbotech delivers 500th laser direct imaging system

Fast Imaging of Blob Motion in TORPEX Plasmas

To complement electrostatic probe measurements of plasma turbulence and study plasma structures with high spatial resolution, a nonperturbative direct imaging system has been developed on TORPEX. This system includes a fast framing Photron-APX-RS camera and a fast gated image intensifier unit. Fast camera movies are acquired at a 150 thousand frames/s frame rate and 2 μs of exposure time. The plasma emissivity profile is tomographically reconstructed from the tangentially viewed image. Conditional average sampling is then applied to visualize and measure the size of structures associated with interchange modes as well as blobs in TORPEX plasmas.

DMD를 이용한 마스크리스 리소그래피 시스템의 고해상도 구현을 위한 다중 빔 에너지 분석에 관한 연구

고 집적 회로의 제작에 있어서 노광 공정은 가장 중요한 기술로 주로 마스크 방식의 노광 방법을 사용하지만 다품종 소량 생산 및 주기적인 제품 변화에 있어서 효율적이지 못하기 때문에 마스크리스 리소그래피 기술이 노광공정에서 각광받고 있다. 본 연구에서는 DMD를 이용한 마스크리스 리소그래피에 있어 다중 레이저 빔의 에너지와 중첩도와의 연관성을 시뮬레이션을 통해 분석하였다. 시뮬레이션을 통해 최적의 스캔 라인 간격을 제시하였고, LDI 시스템을 이용한 노광 실험을 통해 미세 페턴의 정밀도를 향상시킬 수 있었다. Exposure process is the most important technology to fabricate highly integrated circuit. Up to now, mask type lithography process has been generally used. However, it is not efficient for small quantity and/or frequently changing products. Therefore, maskless lithography technology is raised in exposure process. In this study, relations between multi-beam energy and overlay were analyzed. Exposure experiment of generating pattern was performed. It was from presented scan line by multi- beam simulation. As a result, optimal scan line distance was proposed by simulation, and micro pattern accuracy could be improved by exposure experiment using laser direct imaging system.

The catheterization laboratory and interventional vascular suite of the future: Anticipating innovations in design and function

The catheterization laboratory and interventional vascular suite of the future: Anticipating innovations in design and function

Imaging of turbulent structures and tomographic reconstruction of TORPEX plasma emissivity

In the TORPEX [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], a simple magnetized plasma device, low frequency electrostatic fluctuations associated with interchange waves, are routinely measured by means of extensive sets of Langmuir probes. To complement the electrostatic probe measurements of plasma turbulence and study of plasma structures smaller than the spatial resolution of probes array, a nonperturbative direct imaging system has been developed on TORPEX, including a fast framing Photron-APX-RS camera and an image intensifier unit. From the line-integrated camera images, we compute the poloidal emissivity profile of the plasma by applying a tomographic reconstruction technique using a pixel method and solving an overdetermined set of equations by singular value decomposition. This allows comparing statistical, spectral, and spatial properties of visible light radiation with electrostatic fluctuations. The shape and position of the time-averaged reconstructed plasma emissivity are observed to be similar to those of the ion saturation current profile. In the core plasma, excluding the electron cyclotron and upper hybrid resonant layers, the mean value of the plasma emissivity is observed to vary with (Te)α(ne)β, in which α=0.25–0.7 and β=0.8–1.4, in agreement with collisional radiative model. The tomographic reconstruction is applied to the fast camera movie acquired with 50 kframes/s rate and 2 μs of exposure time to obtain the temporal evolutions of the emissivity fluctuations. Conditional average sampling is also applied to visualize and measure sizes of structures associated with the interchange mode. The ω-time and the two-dimensional k-space Fourier analysis of the reconstructed emissivity fluctuations show the same interchange mode that is detected in the ω and k spectra of the ion saturation current fluctuations measured by probes. Small scale turbulent plasma structures can be detected and tracked in the reconstructed emissivity movies with the spatial resolution down to 2 cm, well beyond the spatial resolution of the probe array.

Charge exchange recombination spectroscopy on a diagnostic hydrogen beam—measuring impurity rotation and radial electric field at the tokamak TEXTOR

In this work we present an overview on the charge exchange recombination spectroscopy (CXRS) diagnostic operated with the modulated diagnostic hydrogen beam at the tokamak TEXTOR. The diagnostic setup combines two observation systems used for the measurement of the poloidal (vpol) and the toroidal (vtor) ion velocity component. At TEXTOR a differential Doppler spectroscopy approach (accurate absolute rotation scale) is combined with the high intensity and spatial resolution of a direct imaging system necessary for accurate poloidal rotation measurements on a shot-by-shot basis. This setup allows the full utilization of a 2D CCD detector in the spectral and radial direction. In the case of the poloidal system this allows spatial resolution in the range of mm to cm depending on the intensity requirements for the velocity. The toroidal system comprises a fibre-optic array. The combination of the two measurements with a low-power diagnostic beam can in principle be operated during any available heating scenario without interfering with the discharge. Time resolution is limited by the necessary averaging process; typically a stable plateau of 3 s during a TETXOR pulse is used. The TEXTOR tokamak has the ability to apply momentum input with two tangential neutral beam heating injectors, allowing for measurements under various heating and momentum input scenarios. With the presented diagnostic half the plasma minor radius at a spatial resolution of is covered. With the CVI line at 529.053 nm an accuracy of for the poloidal and ∼5 for the toroidal system is given. The temperature is measured with an accuracy of a few eV. The presented work illustrates the capability of the system during a toroidal momentum scan, showing the self-consistent determination of the radial electric field from experimental CXRS data based on the radial force balance.

Direct Charged-Particle Imaging System Using an Ultra-Thin Phosphor: Physical Characterization and Dynamic Applications

Imaging β rays in vivo will help to advance microdosimetry and radiopharmaceutical development. In an earlier paper [1], we reported a newly developed system capable of directly imaging high-energy electron emissions in small animals in vivo. In this paper, we have thoroughly characterized the performance of the system. We have measured the sensitivity and detectability and the spatial resolution at various magnifications, as well as the linearity of the system. The system has also demonstrated the capability of directly detecting conversion electrons and positrons as well as β rays. The system has been applied to dynamically image spatiotemporal (18)F-Fluorodeoxyglucose (FDG) uptake distributions in xenograft small tumors in dorsal window chambers on mice in vivo. Heterogeneity in FDG uptake in millimeter-sized tumors has been observed.

Direct Visualization of Renal Hemodynamics Affected by Carbon Dioxide–induced Pneumoperitoneum

To examine the direct renal hemodynamics during carbon dioxide pneumoperitoneum in both human and porcine models. Laparoscopic living donor nephrectomy has become widespread because of its minimally invasive nature. However, it has been clear that the renal hemodynamics and function are affected during carbon dioxide pneumoperitoneum. The erythrocyte velocity in the cortical peritubular capillary (CPC) was monitored and measured during laparoscopic nephrectomy on human donors and laparoscopic partial nephrectomy on humans with renal cell carcinoma during carbon dioxide pneumoperitoneum (pressure of 8, 12, 15, 18, and 20 mm Hg). We used a direct imaging system of renal microcirculation by magnifying endoscopy, as previously described. We maintained the same pressure for 5 minutes. In the porcine model (6 pigs), we measured the erythrocyte velocity in the CPC using the same method during carbon dioxide pneumoperitoneum (pressure of 0, 5, 10, 15, 20, and 25 mm Hg). The erythrocyte velocity in the renal artery did not change during increased carbon dioxide pneumoperitoneum. When the pneumoperitoneal pressure was 25 mm Hg, we found that >90% of the erythrocyte velocity in the CPC was nonflowing. In the human model, the erythrocyte velocity in the CPC decreased when the carbon dioxide pneumoperitoneum pressure was 12 mm Hg. The erythrocyte velocity in the CPC decreased during carbon dioxide pneumoperitoneum in all kidneys in both the human and the porcine models. However, erythrocyte velocity in the renal artery did not change during carbon dioxide pneumoperitoneum. After stopping the pneumoperitoneum, the erythrocyte velocity in the CPC recovered immediately. The findings of our study have shown that the suitable carbon dioxide pneumoperitoneal pressure for renal microcirculation is <8 mm Hg for laparoscopic surgery.

Fast visible imaging of turbulent plasma in TORPEX

Fast framing cameras constitute an important recent diagnostic development aimed at monitoring light emission from magnetically confined plasmas, and are now commonly used to study turbulence in plasmas. In the TORPEX toroidal device [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], low frequency electrostatic fluctuations associated with drift-interchange waves are routinely measured by means of extensive sets of Langmuir probes. A Photron Ultima APX-RS fast framing camera has recently been acquired to complement Langmuir probe measurements, which allows comparing statistical and spectral properties of visible light and electrostatic fluctuations. A direct imaging system has been developed, which allows viewing the light, emitted from microwave-produced plasmas tangentially and perpendicularly to the toroidal direction. The comparison of the probability density function, power spectral density, and autoconditional average of the camera data to those obtained using a multiple head electrostatic probe covering the plasma cross section shows reasonable agreement in the case of perpendicular view and in the plasma region where interchange modes dominate.

Digital Imaging Based Measurement of Diesel Spray Characteristics

This paper presents the application of a direct photographic imaging and image processing system in the quantitative characterization of diesel sprays. A high-resolution charge-coupled device (CCD) camera with a flashlight source is used to capture images of sprays in an optically accessible constant-volume chamber. A set of macroscopic characteristic parameters of the sprays, including tip penetration, near- and far-field angles, spray-tip velocity, and average fuel area density, is derived from the images. Experimental work was undertaken on a common rail fuel injection rig. The relationships between the spray characteristics and the corresponding injection conditions are presented and discussed.

49.4: Direct Imaging System by using a UV Pulse Laser and Small Variable Aperture Masks for Color Filter (CF) Fabrication

AbstractWe have now developed a CF fabrication system, which have some small variable masks and expose by the UV pulse laser. The system can handle maximum 8th generation substrates. The feature is that the masks consist of 2 movable apertures and the sizes of apertures are relatively small (about 120 * 150 mm for one imaging head).

Development of Multi-Polygon Laser Scanner Using a Shrink Fitter

A multi-polygon laser scanner system has been developed by using a shrink fitter, in order to produce a new laser direct imager having an ultra wide scanning width and high resolution. The shrink fitter is a new machine element which is cylindrical-shaped and made of plastic materials. This is developed to connect the two machine elements that have different thermal expansion coefficients with a shrinkage fit. In this joining method, the optical axes of the lenses coincide with the axis of the lens-barrel. The positioning accuracy of the lenses in the lens-barrel did not change at any temperature since the shrink fitter sufficiently expanded or contracted in the radial direction to compensate the change in interference. Therefore, the beam spot became very fine all over the wide scanning width at elevated temperature. In this study, we applied laser scanner units using the shrink fitter to the multi-polygon system, which arranged these units in a line. The performance of the new laser direct imaging system was confirmed experimentally.

Some comments on ‘Spatial imaging with 3D capacitance measurements’

In this comment, we provide a critique of the article published by R Wajman et al (2006 Meas. Sci. Technol. 17 2113–8) with regard to 3D electrical capacitance tomography. Moreover, we further examine the sensor design and image reconstruction employed by Wajman et al, and we provide criteria for a robust direct 3D imaging system. References to pioneering and related work on 3D electrical capacitance direct imaging are also included.

X‐ray imaging using avalanche multiplication in amorphous selenium: Investigation of depth dependent avalanche noise

The past decade has seen the swift development of the flat-panel detector (FPD), also known as the active matrix flat-panel imager, for digital radiography. This new technology is applicable to other modalities, such as fluoroscopy, which require the acquisition of multiple images, but could benefit from some improvements. In such applications where more than one image is acquired less radiation is available to form each image and amplifier noise becomes a serious problem. Avalanche multiplication in amorphous selenium (a-Se) can provide the necessary amplification prior to read out so as to reduce the effect of electronic noise of the FPD. However, in direct conversion detectors avalanche multiplication can lead to a new source of gain fluctuation noise called depth dependent avalanche noise. A theoretical model was developed to understand depth dependent avalanche noise. Experiments were performed on a direct imaging system implementing avalanche multiplication in a layer of a-Se to validate the theory. For parameters appropriate for a diagnostic imaging FPD for fluoroscopy the detective quantum efficiency (DQE) was found to drop by as much as 50% with increasing electric field, as predicted by the theoretical model. This drop in DQE can be eliminated by separating the collection and avalanche regions. For example by having a region of low electric field where x rays are absorbed and converted into charge that then drifts into a region of high electric field where the x-ray generated charge undergoes avalanche multiplication. This means quantum noise limited direct conversion FPD for low exposure imaging techniques are a possibility.

Highly sensitive ion imaging system using direct combination of a stacked‐type solid‐state imager and a microchannel plate driven by LabVIEW software

AbstractA direct ion imaging system with single ion detection and high‐precision imaging modes has been developed. This system is composed of a movable microchannel plate unit and a stacked CMOS‐type active pixel sensor (SCAPS). Capabilities of single ion detection were evaluated by ion irradiations using secondary ion mass spectrometry. The experiment shows that this system accurately detected single incident ions. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Modeling for direct imaging of exoplanets data processing

A specificity of direct imaging systems for extra solar planet detection is that neither the residuals of the turbulence, nor the ideal coronagraphed point spread function can be neglected with respect to the planet. This has a direct consequence on the nature of the statistical distribution of the images, which plays a central part in the derivation of a powerful detection algorithm. The purpose of this paper is to study these specific effects: the response of the coronagraph is first analyzed then the statistical distribution of the images is characterized.

Direct Visualization of Cortical Peritubular Capillary of Transplanted Human Kidney with Reperfusion Injury Using a Magnifying Endoscopy

We developed a direct imaging system of renal microcirculation by a magnifying-endoscopy that enables visualization of the movement of erythrocyte in glomerular and cortical peritubular capillary (CPC). We investigated the microcirculation of CPC in the early phase of both living- and cadaveric-donor transplant kidneys. Erythrocyte velocity in CPC were monitored and measured in 20 renal transplants at 20, 60, 90, and 120 minutes after reperfusion. The kidney grafts came from 11 living donors and 9 non-heart-beating cadaveric donors. In living-donor transplants, erythrocyte velocity in CPC at 20 minutes after revascularization declined to one third of baseline value just before nephrectomy and recovered to the prenephrectomy value 120 minutes after reperfusion. In contrast, it continued to be disturbed for 90 minutes in cadaveric-donor transplants. Erythrocyte velocity in CPC more significantly deteriorated in cadaveric transplants than in those of living transplants at 20 through 60 minutes after the revascularization. In living-donor transplants, erythrocyte velocity did not correlate with donor age, both warm (WIT) and cold ischemic time (CIT), time to the initial urination, and best creatine clearance. In the cadaveric transplants, ischemic time, both WIT and CIT, did not correlate with the erythrocyte velocity. However, donor age, duration of acute tubular necrosis, and best creatine clearance after transplantation significantly correlated with the erythrocyte velocity. The measurement of erythrocyte velocity in CPC is a reliable method for predicting the recovery of renal function and reserved renal function of kidney allografts undergoing prolonged ischemia.

Fast mega pixels video imaging of a toroidal plasma in KT5D device

A direct imaging system, viewing visible light emission from plasmas tangentially or perpendicularly, has been set up on the KT5D toroidal device to monitor the real two-dimensional profiles of purely ECR generated plasmas. This system has a typical spatial resolution of 0.2mm (1280×1024pixels) when imaging the whole cross section. Interesting features of ECR plasmas have been found. Different from what classical theories have expected, a resonance layer with two or three bright spots, rather than an even vertical band, has been observed. In addition, images also indicate an intermittent splitting and drifting character of the plasmas.

Tangential soft x-ray imaging for shape and current profile measurements

Flux surface shape information is imaged with an x-ray pinhole camera and used as a constraint for reconstruction of the plasma current and q profiles of plasmas in the low-aspect ratio PEGASUS Toroidal Experiment. The camera system is comprised of a 30 cm Gd2O2S:Pr scintillator plate whose x-ray incident side is lens coupled to a microchannel plate (MCP) image intensifier. A slow-scan charge coupled device (CCD) camera is then lens coupled to the MCP for a time resolution of ∼1 ms. This system will provide photon noise &amp;lt;1% with a 1 ms integration time for intensities typical of Pegasus plasmas. Installation of a 0.2 μm nickel x-ray filter provides necessary contrast between the hot interior and cooler plasma edge region. The scintillator system is compared to direct x-ray illumination of a CCD sensor. Direct illumination uses a custom chip mask and frame transfer for exposure control and sampling at multiple time points. Increased sensitivity of direct illumination imaging system will raise the signal to noise ratio allowing for shorter integration times.

An Observation of the Healing Process of Periapical Lesions by Digital Subtraction Radiography

The purpose of this study was to evaluate the efficacy of digital subtraction radiography using a direct digital imaging system in the follow-up study of endodontically treated teeth. The RVG-S was used as a direct digital imaging system. The intraimage variation of the original RVG-S image caused by dark current and sensitivity variations among pixels was corrected by pixel-to-pixel. The interimage variation was further corrected using a copper step-wedge attached to the sensor. Standardized images were obtained from the same geometrical setup during the follow-up. Pixel values at the regions of interest positioned on the periapical lesion increased after the endodontic treatment, and this change continued during the observation period up to 545 days. The subtraction method with direct digital radiography will be a useful tool to evaluate the healing process in endodontic treatments.