Anode Tube Research Articles

Bone mineral estimation (Hydroxyl apatite equivalent) by direct measurement of photo absorption in the upper extremity (phalanges, radius and ulna) (author's transl)

The x-ray source of the apparatus developed by the authors for bone mineral estimations consists of a small anode tube with a silver anode. The value of the procedure has been tested by in vitro and in vivo experiments. The in vitro measurements were carried out on a bone reference system consisting of a model bone (Reiss) as well as on a macerated tibia embedded in a resin (Heuck). The results were compared with the values obtained by Rassow. It has been shown that the artificial resin is of only limited value as a connective tissue equivalent. The method of mineral estimation using phalanges is described and its reproducibility was tested on 17 parameters. The absorption coefficient of the spongiosa proved to be particularly critical. Finally, measurements, using the forearm, by Cameron's method are discussed briefly.

X-ray curved-crystal monochromator system at the storage ring DCI

Focusing in the horizontal plane is achieved by a Ge crystal shaped to an elongated triangle and mounted as a cantilever so that a cylindrical curvature is obtained with a single micrometer screw; thus, the focus distance can be purposely adjusted. With a crystal asymmetrically cut to (111) planes, the wavelength is tuneable from 0.7 to 3.5 Å and the higher-order harmonics at the detector level are negligible for λ < 1.6 A ̊ (using DCI synchrotron radiation). The optical bench is mounted on a heavy frame with 2 θ rotation. This set-up has been used for small angle scattering and protein crystallography. For this application, actual gain is up to 20 over a 2.4 kW Elliott GX6 rotating anode tube (Ni filtered CuKα radiation), with high spatial resolution and improved S N .

Casting Light on Material Structures

Synchrotron radiation is generated whenever electrically charged particles moving at speeds near that of light are forced into bent paths by magnetic fields. It is electromagnetic radiation, which can be visible light, ultraviolet or X-rays, depending on the energy of the particles and the strength of the magnetic field. The radiation is named for the class of accelerators in which it first became a serious problem, electron synchrotrons. Because electrons have less than 1/1800th as much mass as protons, they reach relativistic velocities at much lower energies than do protons. At high energies synchrotron radiation robs so much energy from electrons moving in circular paths that when what is now the world's most energetic electron accelerator the 20-billion-electron-volt machine of the Stanford Linear Accelerator Center -was planned, the builders decided to make it a straight line two miles long. It may be considered somewhat ironic that that linear accelerator now supplies accelerated electrons to a facility that uses synchrotron radiation for research in several different scientific fields. Synchrotron radiation used to be considered a dead loss by accelerator operators. In recent years it has suddenly become a very important new research field. In the words of Herman Winick, deputy director of the Stanford Synchrotron Radiation Laboratory, There is an explosive growth of interest in its applications. At the moment there are about 10 storage rings and 11 synchrotrons around the world at which synchrotron radiation experiments are done. The SSRL gets its synchrotron radiation from the SPEAR storage ring. A smaller storage ring at the University of Wisconsin, the Deutsches Elektronen-Synchrotron at Hamburg, and more than one ring at Novosibirsk in the USSR are among those in the world now supplying synchrotron radiation for experiments. The attitude of the U.S. scientific establishment and its government funders has undergone a total turnaround from three or four years ago, Winick says. At that time Winick was working at the now defunct Cambridge Electron Accelerator in Cambridge, Mass. An attempt to get $1 million a year to keep the CEA going as a facility for synchrotron radiation was unsuccessful. Over the next three years, the National Science Foundation plans to give about $7 million to the SSRL alone. At the same time, plans have been announced for enlargement of the facility in Wisconsin and for another national synchrotron radiation facility at Brookhaven National Laboratory, where an accelerator will be built to be solely a source of synchrotron radiation. Other sources of X-rays, of which the best are 60-kilovolt rotating anode tubes, do not provide the broad spectrum or high power of synchrotron radiation. As an example of the difference, Winick cites a group of scientists from the Bell Telephone Laboratories who came to SSRL to do a spectrum that they had previously done by other methods. With synchrotron radiation it took them 20 minutes to do a spectrum that had previously taken two weeks. Another advantage of synchrotron radiation is that it comes in bursts that correspond to the bunches of electrons circulating in the storage ring. This gives experiments a built-in time resolution and makes possible the study of chemical and biological processes over time. A study of contracting muscle fibers is one possible experiment. Other biological possibilities include studies of membrane action, which are a particular interest of Sebastian Doniach, who has just completed his The two-mile linear accelerator feeds electrons to the SPEAR storage ring (lower right of top picture), where they generate synchrotron radiation used by the SSRL (building at right of ring). Mirrors permit several experiments to share one radiation beam (bottom).

Generation of an Intense Ion Beam by a Pinched Relativistic Electron Beam

The tightly pinched electron beam of a pulsed electron accelerator is used to generate an intense beam of ions. A foil anode and vacuum drift tube are used. The space-charge field of the pinched beam in the tube accelerates ions from the foil anode. Ion currents of 10 kA at a density of 5 kA/cm/sup 2/ with pulse length of 50 nsec are obtained using a 5 kJ, 450 kV, 3-..cap omega.. diode. (AIP)

Serial cerebral angiography in stereoscopic magnification

A ceiling x-ray tube support with synchronous up and down movements is described for obtaining two parallel x-ray beams with a short focal-film distance. Stereoscopic cerebral angiography is performed with direct serial magnification using a heavy-duty anode tube with a 0.1 mm focus. This technique combines the advantages of magnification and stereoscopic angiography. Small arterial and venous changes can be observed clearly in three dimensions. The usefulness and limitations of this method are discussed using clinical and experimental data.

A multiconfiguration relativistic DIRAC-FOCK program

In this paper, we present a theoretical study of the X-ray fluorescence emission after vacancy of K-shell due to electron impact ionization. In particular, we focus on the angular distributions of the characteristic Kα emission lines following this process. Rh was chosen for the analysis since it is a common element in X-ray tube anodes. In this analysis we also considered some elements along the period-4, i.e., Ni, Cu and Co as case-studies. In doing so, we studied the magnetic sub-level population of the ionized states, which is directly related to the angular distribution of the emission. A relative low angular distribution for the Kα emission of Rh of 0.5% was observed, which makes the assumption of isotropic emission correct for most studies. Moreover, a comparison with the respective angular emission for adjacent elements in the fourth period of the periodic table shows that this isotropy is attributed to a small total angular momentum of the resulting configurations after ionization, as well as to opposite angular distributions of the various transitions, which average to a maximum of 0.7% angular asymmetry in Ni.

200kVpX線撮影の検討

In general, conventional high voltage roentgenography is performed at maximum voltage of 150kVp. On roentgenography at 200kVp, several investigations already reported were performed by roentgen therapy apparatus. At presents, diagnostic apparatus as 200kVp is available. The apparatus used here is Hitachi X-ray geneator (DR-205) and Philips's rotating anode tube (Super Rotalix 200) with focal spot size of 1.2mm and 0.6mm. The purpose of this paper is to investigate the property of focal spot size and capacity of phototimer (Hitachi Hi-Auto), and to test a new intensifying screen (KYOKKO LT-2) highly sensitive films (Fuji RXS and Sakura QS) at 200kVp roentgenography. 1) The focal spot size of the tube is not changed within the range of 100,150 and 200kVp. 2) Film density of chest roentgenograms taken with the phototimer are sufficiently controled at 200kVp. 3) The quality of images with new screen is compared with those screens HV, FS and VP. Sharpness of VP is superior than that of LT-2 but is difference is small, and less sensitive. HV is more sensitive at 200kVp than LT-2 but image quality is inferior. Quality of FS is almost same as LT-2 but less sensitive. So, it is concluded that the LT-2 is the best at 200kVp roentgenography. 4) Surface dose with sensitive films is reduced to 60 per cent of that with conventional films and image quality is almost same. 5) When filter of 1.0mm Cu+0.5mm Al is added, it is possible to reduce the surface dose less than one third.

Simple and Fast Method for the Presentation of the Two-Dimensional Modulation Transfer Function of X-Ray Systems

A method for the evaluation of the two-dimensional MTF of x-ray systems is described. In a first step a statistical distribution of lead grains is imaged by the x-ray systems. In the second step this image is Fourier transformed in a coherent optical processor giving the two-dimensional display of the MTF. A demonstration of the method is given by showing the dependence of the MTF on shape and size of the focal spot of the x-ray tube and the nonshift invariance of a system using a rotating anode tube. Furthermore the application of the method in tomographic x-ray systems is tested.

The K X-ray Fluorescence Spectrum of Neon

Neon gas at a pressure of 500 Torr was excited by X-rays from a chromium anode tube, and the neon K emission spectrum was measured with the photon counting technique. The radiation was analyzed with a planar potassium-acid-phthalate (KAP) or gypsum crystal in a single-crystal vacuum spectrometer. The recorded spectra were corrected for instrumental distortions, and the relative integrated intensities of the α"α'α3α'3α4- and α5α6-satellite groups were obtained. The relative intensities agree with LaVilla's electron excitation results within the error limits. Hence, the satellite intensity seems to be independent of excitation mode if the excitation energy is sufficiently high. The relative KL intensity is 27% greater and the relative KL2 intensity is 160% greater than the calculated shake-off value. The multiplet structure of the α"α'α3α'3α4-group was found to be in accordance with earlier identifications except with that of Sureau.

An X Ray Tube Anode Current Stabilizer

An x ray tube anode current stabilizer circuit employing a triac is described. This circuit combined with a dc x ray system provides a high degree of stability suitable for continuous x ray inspection systems.

Absolute power measurements in small angle X-ray scattering with gas scattering calibration

The calibration of a high intensity X-ray beam from a rotating anode tube has been accomplished with the small angle scattering from three heavy gases used as primary standards because their scattering cross sections at zero angle could be calculated. The scattering of the three gases permitted calibration of the incident beam and geometry to ±2%. A scattering 10% in excess of that predicted from the thermodynamic relationships was observed for water, ethyl alcohol, xylene, and benzene. This excess was ascribed to double scattering. Possible application of these methods to determine the molecular weight of macromolecules was investigated. Scattering observed from solutions of metmyoglobin was within 3% of the predicted scattering. For ribonuclease a 35% excess over predicted scattering was observed and was ascribed to aggregation, of the molecules, shown by ultra centrifuge methods to occur in these solutions.

SOFT X-RAY TUBE FOR ELECTROSTATIC CYLINDRICAL ELECTRON SPECTROGRAPHS

The soft x-ray tube with the aluminum anode, for photoelectron spectroscopy with a cylindrical electron spectrograph, has been constructed and tested. The construction permits 20 mm distance between the tube anode and the sample. The testing anode voltage was 5 kV and anode currents 2.5, 5, and 7.5 mA. The stability of the tube was satisfactory. During the test of 5.5h for each current the contamination of the anode surface, caused by the oil from the diffusion pump, decreased the intensity of the tube 10–20%.

The central x-ray beam in stereotaxis.

A common misconception is that there exists only one possible x-ray arising from x-ray tube and that it is one that somehow is oriented to axis of x-ray tube on its collimator. However, following axiom in radiology is emphasized: emanating from a point source of radiation (the x-ray tube anode) is an infinite number of x-ray beams, any one of which may be selected as the central x-ray beam. In stereotaxis particular beam selected will be that one which traverses a pathway from x-ray tube anode through 2 defined points on stereotaxic frame.This pathway can be selected prior to stereotaxic procedure by sighting through these 2 points and adjusting x-ray tube and/or stereotaxic frame until these points visually superimpose on x-ray tube anode or its aluminum filter. Regardless of gross position of stereotaxic frame with respect to x-ray tube, within limits, 2 defined points will have their roentgenographic images superimposed on the...

New Approach to rf-Sputter Power Supply Design

rf transmission line and matching network have been eliminated. The rf generator with primary coil is detachably mounted directly on the feedthrough flange for the target which is connected directly to the secondary coil. This results in a much more compact unit, eliminating rf-power losses, thereby increasing the overall efficiency and reducing substantially the number of components in the power supply. The final amplifier tube anodes are operated at de ground potential. This allows water cooling of the anodes by feeding the cooling water through a double helical resonant coil terminating both water inlet and outlet at ground potential. Water cooling furthermore reduces the size of the rf generator. No dc potential is superimposed on the rf potential. Therefore, relatively low voltage breakdown rf components can be used. rf arc-over, if it should occur, will not cause dc arcing. Rugged low cost medium power tubes are used in parallel connections for high power at low impedance. This also contributes to the usability of low voltage breakdown components. For lower power requirements, filaments of parallel tubes may be de-energized. This provides coarse matching of impedance to smaller targets while reducing rf power to desired levels. Fine control of impedance matching is obtained by variable inductive coupling.

STUDIES ON PHOTOFLUOROGRAPHY OF THE UPPER URINARY TRACT

To detect the abnormal shadows of renal pelves and calyces in detail, the author applied a high-voltage photofluorographic technique to the upper urinary tract.The photograms were taken by 60×60mm serial films using Toshiba X-Ray Apparatus KCD-12F type with rotating anode tube and indirect X-Ray Canon Camera. Some 10 serial films in a patient were taken at 120KV and 70cm distance.Films of 63 cases were examined, which consisted of plain films of the abdomen (10 cases), intravenous urograms (17 cases) and retrograde pyelograms (36 cases). And the results are follows:1) Owing to the high-voltage photofluorography, bony shadows and intestinal masses became faint without any enema, evacuant or diet restriction.2) Because of serial photography, stereographic observation was possible when the position was changed gradually.3) On the intravenous urograms, if the kidney function normally, the calyces and pelvis were visualized within 2-3 minutes after the injection in the supine position. When the patient took upright position, the media were excreted from the pelvis immediately.4) On the retrograde pyelograms, so-called “emptying times” of the each calyces and the pelvis in the normal kidney were studied. The times of the upper, middle and lower calyces and the renal pelvis were less than 5 minutes, 4 minutes, 5 minutes and 3 minutes in supine position and 2 minutes, 4 minutes, 4 minutes and 3 minutes in upright position, respectively.5) Photofluorographic changes in 16 cases of essential renal hematuria were dilatation of renal pelvi-calyceal system (68.7%), reflux of media from renal pelvis to calyces (43.7%), Narath's symptom (43.7%), movable kidney (31.2%), flexion of ureter (31.2%) and sustaind small shadow in one calyx (18.70).6) Photofluorographic changes in 14 kidneys of nephroptosis were flexion of ureter (100%), dilatation of renal pelvi-calyceal system (71.4%), Narath's symptom (64.2%), rotation of the kidney (50%) and reflux of media from renal pelvis to calyces (21.4%).

IMAGE DISTORTION IN CINERADIOGRAPHIC EQUIPMENT.

The development of cineradiographic image-intensifier tubes has opened a new vista for studying rapidly occurring cardiovascular events. Such motion-picture radiographic technics are being used in an increasing number of physiologic laboratories as an adjunct to hemodynamic studies (1–6). In the Cardiovascular Laboratory of Duke University Medical Center, films taken at 60 frames per second have been used for the purpose of recording instant-to-instant changes in the size and contour of the opacified ventricle (7) under a number of conditions. Early in these studies it became apparent that image-amplification technics introduced measurement errors due not only to symmetrical magnification but also to asymmetrical magnification. Symmetrical magnification is produced by table design, resulting in a short tube-to-target distance, and limitations of x-ray tube output. Such magnification is not unique to image-intensifier systems. It must be considered in all radiographic technics but can be corrected mathematically by applying the rule of similar triangles where a = distance from the x-ray tube to the receiving surface (input phosphor) b = distance from the x-ray tube to the plane of interest x = true object size y = projected object size on the receiving surface Asymmetrical magnification or distortion is not a problem in conventional radiographic systems. It is peculiar to image-intensifier units and cannot be corrected by the rule of similar triangles. The present studies were designed to delineate the magnitude and cause of distortion in commercially available image-intensifier tubes and to determine how to minimize this factor. A report of this work seems indicated as the problem of distortion may not be widely appreciated by clinical physiologists and possibly radiologists using this type of equipment. Method and Results An 8-inch image-amplifier tube, a 200-ma, 125-kvp x-ray generator, a fractional-focal-spot rotating anode tube, and a 35-mm. camera comprised the equipment in our laboratory. Measurements were taken from this unit on two occasions. We obtained measurements also from a similar 8-inch amplifier tube on the factory test bench while varying the electron lens voltage supply. Our initial phantom, of wire mesh, was discarded because of the innumerable measurements required in order to quantitate the problem. A phantom of milled slugs arranged in a radial pattern was also discarded as it produced confusing penumbra. Finally, a thin metal sheet in which we drilled holes of known size in a radial pattern was adopted (Fig. 1). A similar phantom (Fig. 2) was used in the factory tests. Short cineradiographic strips were made with the phantom placed between enough sheets of Presdwood to equal the scatter from a medium-sized animal. The phantom was also photographed directly with a 35-mm. camera. The cine strips and photographs were then enlarged and printed by the same technic.

Measurement of the coherence of grid and anode tube noise

Measurement of the coherence of grid and anode tube noise

Frequency Spectra of Low-Frequency Fluctuations in a Plasma

Observations have been made of the low-frequency fluctuations occurring in hot-cathode dc mercury-vapor discharges at a pressure of approximately 1 μ. A spectrum analyzer was employed to study frequency spectra from three widely differing experimental tubes and to determine the effects of variations in tube geometry, electrode spacing, and anode current. Similar measurements were also made at points along a long discharge column with the aid of a capacitive probe sliding on the outside of the tube. The character of the spectrum is markedly dependent on tube geometry, substantially independent of column length and position along the column, and may be coarse or contain relatively pure frequency components. Two mechanisms observed involved frequency variation proportional to the square and cube roots of anode current, and possible explanations are given. There is, however, evidence for the existence of other basic mechanisms of generation.

A Report on the Use of Grids for Fluoroscopy

Up to the past few years, it was a relatively easy task to select a stationary grid. If it was intended for radiography, the one with the finest pattern and best “clean-up” was chosen. These qualities were frequently determined by obtaining a roentgenogram of a thick and high-density area of the body (e.g., a lateral view of the lumbar spine). Before rotating anode tubes came into common use for spot-filming, many radiologists had to be content with small-field “non-grid” spots. This was necessary because of the limited loading factors for stationary anode tubes and the long exposure times required with grids. When high-capacity rotating anode tubes became available, many radiologists began to employ stationary grids for fluoroscopy and spot-filming. Today several manufacturers make radial, parallel, and crisscross grids in at least seven ratios, with metal, pith, or plastic interspace material. The purpose of the study to be reported here was the evaluation of six commercially available grids suitable for use with the under-table fluoroscopic x-ray tube and of two new experimental grids. Because of high absorption, grids with ratios greater than 8∶1 were not studied. The choice of a grid for any roentgen application is governed by: (a) the thickness and opacity of the part in question; (b) the size and/or volume of the field to be examined; (c) the kilovoltage to be used. A significant change in any one of the three factors will alter the requirements for the grid The shuttered-down field sizes for fluoroscopy rarely exceed 8 × 10 inches. Indeed, the overall size of the fluoroscopic screen in American apparatus is hardly ever larger than 12 × 12 inches. It follows that the quantity of scattered radiation encountered is frequently less than that in conventional radiography, where patient areas as large as 14 × 17 inches are commonplace. For the tests, each grid was assigned a serial number from 1 to 8. Absorption Ratings for Fluoroscopy and Image Intensifiers4 For conventional fluoroscopy the Radelin FGP screen (1960 serial number 001901) was used. The arrangement of x-ray tube, phantom, and ”light”-measuring equipment is shown in Figure 1. This relationship of apparatus was maintained throughout the tests, and several readings were made and averaged for each grid. The results of this procedure in order of increasing absorption are shown in Table I. Image Intensifiers: Similar tests were run with the Picker 22-cm. intensifier image tube (gain 1,250) and the light-emission of the output phosphor was measured with each grid interposed. Resuits show the same relationship charted above for the conventional screen. Many of the early intensifies in use have gains of 500 and less. The substitution of a low-absorption grid for one with high absorption may mean the difference between “cone” and “rod” vision for many examinations.

Photovoltaic response of selenium barrier layer cells to X-radiation in the energy range of 15-40 keV

Twenty selenium barrier layer cells, made by a modern commercial process with a variety of modifications, were examined with irradiation of x-rays in the 15-40 kev energy range and the behaviour was compared with their response to light. The x-ray sensitivity is found to be independent of intensity of irradiation at constant x-ray tube anode voltage, but linearly proportional to anode voltage at constant anode current. The form of transient response to x-irradiation depends on the intensity of irradiation and the previous history of cell irradiation, a time of rest of about 2 hours being required to achieve the `first-irradiation' response. The fatigue effect does not occur in the steady-state values to photovoltage and photocurrent. There is some evidence for a qualitative relationship between x-ray and optical photovoltage sensitivities of a cell, but there is no relationship between the photocurrent sensitivities.