High Voltage X-ray Tube Research Articles

Subsurface density mapping of the earth with cosmic ray muons

Since its original discovery by Wilhelm Conrad Rontgen in 1895, one of the directions of researchers pursued was an application of x-ray radiography to larger objects, while the advent of high voltage x-ray tubes allowed radiographs of industrial objects to be produced in a reasonable amount of time. In spite of the great motivation we have to survey the earthʼs interior, we now know that x rays are not sufficiently penetrative to successfully target geophysical objects. Our current knowledge about the cross sections of the muon with matter solves the problem about this x-rayʼs inspectable size limit. These particles do not interact strongly with matter, and those with relativistic momentum travel long distances penetrating deep into rock. By tracking the ray paths of the muon after passing through the object, the method gives researchers the ability to study the earth in new ways. The purpose of this article is to review recent progress in probing the earthʼs interior with muons.

Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans

To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Four different bone removal methods were applied to CT scans of an anthropomorphic thorax phantom, acquired with a second generation dual source CT scanner. The methods differed by the way information on the presence of bone was obtained (either by using an additional, nonenhanced scan or by scanning with two tube voltages at the same time) and by the way the bone was removed from the CTA images (either by masking or subtracting the bone). The phantom contained parts which mimic vessels of various diameters in direct contact with bone. Both a quantitative and qualitative analysis of image quality after bone removal was performed. Image quality was quantified by the contrast-to-noise ratio (CNR) normalized to the square root of the dose (CNRD). At locations where vessels touch bone, the quality of the bone removal and the vessel preservation were visually assessed. The dual energy based methods were assessed with and without the addition of a 0.4 mm tin filter to the high voltage x-ray tube filtration. For each bone removal method, the dose required to obtain a certain CNR after bone removal was compared with the dose of a reference scan with the same CNR but without automated bone removal. The CNRD value of the reference scan was maximized by choosing the lowest tube voltage available. All methods removed the bone completely. CNRD values were higher for the masking based methods than for the subtraction based methods. Single energy based methods had a higher CNRD value than the corresponding dual energy based methods. For the subtraction based dual energy method, tin filtration improved the CNRD value with approximately 50%. For the masking based dual energy method, it was easier to differentiate between iodine and bone when tin filtration was applied. The CNRD value decreased only with 4% in that case. Compared to the dual scan based methods, the dual energy based methods had the advantage that only a single scan was made without the need of image registration. This might be easier to implement in clinical practice. Vessel preservation was better with bone subtraction than with bone masking. Smaller vessels were completely occluded by the bone mask. None of the bone removal methods was dose neutral. In general, dual scan based methods that use the lowest tube voltage available, have a higher CNR than the dual energy based approaches at the same dose level. Tin filtration improves the ability to differentiate between iodine and bone for the dual energy based masking method. In clinical practice, the advantages of the dual energy masking method might outweigh its disadvantage of a slightly higher dose penalty compared to the conventional dual scan masking method.

Low-power-loss and high voltage X-ray tube with graphite nanospines cold cathode

Abstract We report a low-power-loss and high voltage X-ray tubes with a graphite nanospines (GNS) cold cathode. The cathode is encapsulated in a glass tube having a Beryllium window with a Tantalum film to generate X-rays. The internal tube pressure was below 10 −7 Pa and a tube current exceeding 1 mA at a tube voltage of 22.9 kV was observed in the fabricated X-ray tube. The tube current dispersion, defined as standard deviation/mean ( σ /mean), was relatively small at 2.4%. An X-ray radiation dose rate exceeding 5 Sv/h was obtained from the X-ray tube and the radiation dose rate dispersion was also small ( σ /mean=0.3%). As an application of the X-ray tube, we demonstrated radiography for the rapid inspection of organic products.

Low-power-loss and high voltage X-ray tube with graphite nanospines cold cathode

We report a low-power-loss and high voltage X-ray tubes with a graphite nanospines (GNS) cold cathode. The cathode is encapsulated in a glass tube having a Beryllium window with a Tantalum film to generate X-rays. The internal tube pressure was below 10 −7 Pa and a tube current exceeding 1 mA at a tube voltage of 22.9 kV was observed in the fabricated X-ray tube. The tube current dispersion, defined as standard deviation/mean ( σ/mean), was relatively small at 2.4%. An X-ray radiation dose rate exceeding 5 Sv/h was obtained from the X-ray tube and the radiation dose rate dispersion was also small ( σ/mean=0.3%). As an application of the X-ray tube, we demonstrated radiography for the rapid inspection of organic products.

Microcollimator for Micrometer-Wide Stripe Irradiation of Cells Using 20–30 keV X Rays

Abstract Pataky, K., Villanueva, G., Liani, A., Zgheib, O., Jenkins, N., Halazonetis, D. J., Halazonetis, T. D. and Brugger, J. Microcollimator for Micrometer-Wide Stripe Irradiation of Cells Using 20-30 keV X Rays. Radiat. Res. 172, 252-259 (2009). The exposure of subnuclear compartments of cells to ionizing radiation is currently not trivial. We describe here a collimator for micrometer-wide stripe irradiation designed to work with conventional high-voltage X-ray tubes and cells cultured on standard glass cover slips. The microcollimator was fabricated by high-precision silicon micromachining and consists of X-ray absorbing chips with grooves of highly controlled depths, between 0.5-10 microm, along their surfaces. These grooves form X-ray collimating slits when the chips are stacked against each other. The use of this device for radiation biology was examined by irradiating human cells with X rays having energies between 20-30 keV. After irradiation, p53 binding protein 1 (53BP1), a nuclear protein that is recruited at sites of DNA double-strand breaks, clustered in lines corresponding to the irradiated stripes.

Three Dimensional Computerized Microtomography in the Analysis of Sculpture

The Alte Nationalgalerie, Staatliche Museen zu Berlin (SMB) and the Federal Institute for Materials Research and Testing (BAM) tested the accomplishment of the three dimensional computerized microtomography (3D-microCT)-a new flat panel detector computerized tomography (CT) system at the BAM with extended energy range, with high voltage X-ray tubes (330 and 225 kV), with micrometer focal spot size and micrometer resolution and enlarged object size (up to 70 cm diameter)-for examining plaster statues. The high spatial and density resolution of the tomograph enable detailed insights into the individual work processes of the investigated cast plaster statues. While initiated in support of the conservation process, computed tomography (CT) analysis has assisted in revealing relative chronologies within the series of the cast works of art, thus serving as a valuable tool in the art-historical appraisal of the oeuvres. The image-processing systems visualize the voids and cracks within and the cuts through the original cast works. Internal structures, armoring, sculptural reworking as well as restorative interventions are virtually reconstructed. The authors are currently employing the 3D-microCT systems at the BAM into the detection of defects in Carrara marble sculpture. Microcracks, fractures, and material flaws are visualized at spatial resolution down to 10 microm. Computerized reconstruction of ultrasound tomography is verified by analyzing correlations in the results obtained from the complementary application of these two non-destructive testing (NDT) methods of diagnosis.

Evaluation of the energy‐dispersive x‐ray spectra of high‐Z elements using Gaussian and Voigt peak shape profiles

AbstractThe AXIL computer program, aimed at x‐ray spectral deconvolution, was extended in order to take into account the broadening of peaks of K‐series radiation of high‐Z elements (Z > 50) due to the increasing contribution of the natural linewidth to the peak width. This effect needs to be taken into account in energy‐dispersive spectrometry of K‐series radiation of heavy elements, such as W, Au, Pb and U. The so‐called Voigt peak profile function was implemented into the AXIL computer code. Based on the published literature data, a library of natural atomic level widths was created, containing the data for K, L1, L2, L3 atomic level widths of elements up to Z = 94. The database was necessary to calculate the Voigt peak profiles. The AXIL program user interface and the fitting procedures were adapted, allowing us to perform spectral evaluation using either Gaussian or Voigt peak profiles. The relevance of fitting the x‐ray spectra of K‐series radiation of high‐Z elements with the Voigt peak shape model versus Gaussian peak approximation was thoroughly examined with the aid of simulated and measured spectra. The experimental x‐ray spectra were measured using a high‐voltage x‐ray tube spectrometer utilizing a 130 kV/65 W tungsten anode x‐ray tube and an ultra‐low energy germanium detector. The results obtained showed that when using the Gaussian peak model the calculated peak areas and fitted peak widths are systematically biased. It was found that the value of the systematic error is a linear function of the ratio of the natural linewidth to the spectrometer energy resolution at the peak position. Copyright © 2001 John Wiley & Sons, Ltd.

Quantitative X-Ray Fluorescence Analysis Using Fundamental Parameters: Application to Gold Jewelry

The fundamental parameter method was applied to the quantitative x-ray fluorescence analysis of gold jewelry samples. The fluorescence spectra were acquired using monochromatic and focused W Kα 1 radiation (59.32 keV) from a high-voltage x-ray tube and a Ge solid-state detector. A novel program package based on a whole-pattern fitting procedure including corrections for secondary fluorescence and escape peaks was developed. The accuracy of this method was tested by analyzing samples characterized with independent techniques.

Directional Distribution of 1040-Kev Radiation from a High Voltage X-Ray Tube

The distribution of the 1040-kev x-rays emitted in various directions by a high voltage x-ray tube has been measured by means of an indium resonance detector.

A million-volt resonant-cavity X-ray tube

A very compact high-voltage X-ray tube is described, in which the accelerating voltage is developed in a resonant cavity excited by a high-power magnetron operating at a wavelength of 25 cm. A mean current of 70 μA has been obtained at a peak voltage of 1.1 MV. Two points of interest are that the focal spot is very small (approximately ½ mm in diameter) and that, because the output is pulsed, the tube may be used as a stroboscope for the radiography of moving machinery. The limitations which apply to this method of acceleration are discussed.

The St. Bartholomew's Hospital X-ray tube for one million volts

A description is given of the high-voltage X-ray tube and one-million-volt d.c. generator installed in the Mozelle Sassoon X-ray Therapy Department of St. Bartholomew's Hospital. The building contains a treatment room located between two generator rooms. The central portion of the X-ray tube, from which the X-ray beam emerges, traverses the treatment room and projects into each generator room. The generator rooms each house 500-kV d.c. generators. The X-ray tube and thermionic rectifiers used in the d.c. generators are evacuated continuously by oil diffusion pumps, and the whole apparatus is readily demountable. Removable filament assemblies are fitted to the rectifiers and facilitate rapid replacement of filaments; and a special cathode with 6 interchangeable filaments has been developed for the X-ray tube to avoid frequent admission of air into the tube during filament replacements. The tube is now used continuously at 1 000 kV and has been operated experimentally at 1 100 kV. Several structural changes have been, made for reasons stated later, and the performance of the tube is fully described. Curves relating X-ray output with voltage and filtration by metallic niters are given, and a radiograph as included to illustrate the capabilities of the tube if applied to industrial radiography. Comparisons are made between this tube and high-voltage tubes operating in other parts of the world.

The Development of High Voltage X-ray Tubes at the California Institute of Technology

THE difficulties encountered in constructing x-ray tubes for operation at voltages above two or three hundred kilovolts are well known. Stray charges may accumulate on the envelope in such a manner that a dangerously high potential is applied through the wall, with the result that it is punctured. Punctures may also result from tiny pieces of metal torn out of the electrodes by the intense electric fields. Gas may be liberated by stray bombardment caused by the field and resulting in destructive discharges. These difficulties may be at least partly eliminated by several means. We have attempted to decrease the stray discharges by using electrodes with large curvature and large spacing, so as to decrease as far as possible the field strength at the surfaces. In addition, the glass or other envelope is protected against stray discharges and excessive potentials by proper subdivision and shielding, and any gas which may be liberated during operation is quickly removed by fast pumping. The first tube to be used for experimental x-ray work at potentials in excess of 300 kv. was constructed in 1928. This tube was operated intermittently at 750 kv. peak, and cold emission was depended on for the source of electrons. Figure 1 shows a section through this tube which is mounted in a temporary wooden structure. The potential is applied between the long inner electrode and the bottom plate, which is at ground potential. It will be noted that the glass wall is nowhere exposed to the full potential and that it is thoroughly protected against stray bombardment. It was a simple matter to equip this tube with suitable filament and to provide adequate protection for operation and observation at close range. Continuous operation was obtained at 600 kv. peak and from 4 to 5 ma. electron emission. Such a tube is shown in Figure 2. Since no equipment of comparable voltage was at the time available elsewhere, it seemed highly desirable that an attempt be made to learn if x-rays produced at such high potentials are in any respect superior to other forms of radiation for the treatment of malignant disease. After much preliminary work with animals and many consultations with men of high standing in the medical profession, it was decided to treat selected cases of advanced deepseated malignant tumors. Treatment was started in October, 1930, and has been continued up to the present time. In 1931, Mr. W. K. Kellogg became interested in the work and generously provided funds for erecting and equipping a new laboratory to be devoted to clinical research in radiation. The laboratory and a new tube, designed to operate at 1,000 kv., were completed the same year, but actual operation of the plant was delayed for nearly a year due to difficulties in design and construction of the transformers, and regular treatment did not begin until September, 1932. Since that time this equipment has been in daily use for the treatment of malignant disease.

Generators for Gamma Rays and Neutrons and Radiotherapeutic Possibilities

THE technic of high voltage generators and high voltage discharge tubes for the production of penetrating x-rays has been successfully applied to nuclear physics. In fact, generators for one million volts and more, designed to produce x-rays by accelerating electrons (the usual way), can be used to accelerate positive particles merely by reversing the tension. Positive particles may be produced by voltages of the order of 50 kv. in tubes not essentially different from the good old gas tubes, the positive ions emerging through a hole in the cathode. These positive ions (canal rays) are protons if the gas in the discharge tube is hydrogen, deutons in the case of heavy hydrogen, and α-particles in the case of helium. The acceleration of the positive particles takes place in a tube which shows, as we shall see in more detail later on, a great analogy with a high voltage x-ray tube. At the other hand, the results of nuclear physics have stimulated further development of high voltage technic. Generators for voltages of many millions of volts have been designed. The first interesting nuclear reaction by means of high voltage was performed by Cockcroft and Walton in 1932 (1). The lithium nucleus was split up into two helium nuclei or α-particles by means of protons accelerated with a voltage of some hundreds of kilovolts. It was shown later that this reaction is possible with voltages as low as 10 kv. (2, 3); but the output increases rapidly with the voltage, as is the case for most nuclear reactions. Moreover, many reactions cannot be expected to take place below certain minimum voltages. So, for instance, may a beryllium nucleus be split up by x-rays or γ-rays equivalent to one and a half million volts as a minimum value. At voltages of little over one million volts (1 mv.) a very interesting phenomenon appears: a gamma quantum is transformed into a pair of particles, a positron and an electron. The production of x-rays (γ-rays) of one million volts becomes extremely efficient, the output at one million volts being equivalent to more than 1 kg. of radium at 1 ma. tube current. A short description of a high voltage generator developed by the author, given at the American Congress of Radiology in 1933, has been published (4). This generator has been further developed up to a voltage of four million volts. A full description has been published recently (5). The article contains also a brief critical survey of the other methods to produce fast particles with and without high voltages. Figure 1 shows a generator of two million volts to earth, being the negative half of a four-million-volts set at the Eindhoven laboratories. Figure 2 shows a one and a quarter million volts generator delivered to, and in use for many months now at, the Cavendish Laboratory, Cambridge. For further details we refer to the paper mentioned above (4) and proceed to describe—(a) A million-volt x-ray or γ-ray tube of the sealed-off type; (b) A high voltage neutron tube.

High Voltage X-ray Tubes in the U.S.A. Part I

In recent years a number of X-ray tubes operated at voltages between 500 and 1,000 K.V. have been used in the U.S.A. for the treatment of deep tumours. These tubes must ultimately be judged by their performance in clinical practice, but their users are reluctant to make a report of this nature until greater experience has been gained. At present, therefore, their discussion must be restricted to technical and financial aspects, and to considerations of utility. Nevertheless it is desirable to bear in mind the reasons which have led to the development of these more complicated and costly installations. They may be summarised as follows:— 1. Theory suggests that the shorter the average wavelength of the radiation used, the greater will be the depth dose obtained, and this is supported by experience with the lower voltage type of X-ray tube. 2. It is possible that shorter wavelength radiation is preferable for biological reasons, so that such radiation should receive an adequate trial. 3. Radium is a source of short wavelength radiation which fulfils the requirements of (1) and (2) better than X rays from any high voltage X-ray tube which can be built at present. However there are considerable differences in the techniques of using gamma rays and X rays, so that it is desirable to test the combination of X-ray technique and short wavelength radiation. Moreover, there is not sufficient radium available to treat all deep tumour cases, so that an alternative source of short wavelength radiation is valuable.

Two Applications of the Sylphon Bellows in High Vacuum Plumbing

The term vacuum plumbing is intended to express briefly the mass of technique which has recently been developed by which vacua from 10^(-4) to 10^(-6) mm Hg or better are obtained in systems mainly of metal and of large volume. The large high voltage x-ray tubes and ion accelerating tubes of C. C. Lauritsen at the California Institute of Technology, E. O. Lawrence at Berkeley and Merle Tuve at the Bureau of Terrestrial Magnetism are three examples of such systems.

High Voltage X-ray Tube and Constant Potential Transformer Equipment

This is a preliminary report on the design, construction and operation of a porcelain insulated, grounded anode X-ray tube, to operate at 800,000 volts constant potential. This is a hot cathode tube with water-cooled anode.

Whole Animal Exposures to Highly Filtered Gamma Rays

I. Introduction SINCE the development of high voltage x-ray tubes operating at voltages of the order of a million volts, the question of adequate protection for those engaged in this work against the very penetrating gamma-rays which are produced, an appreciable fraction of which passes through whatever shielding may be used, has become of considerable importance. More and more laboratories are expending efforts in this direction, a development which makes not only possible but practical the use of such tubes for medical applications. Roughly speaking, an x-ray tube operating at a million volts and 4 ma. gives off as much radiation as would be obtained from 1,000 grams of radium, and when 4 or 5 inches of lead is used to shield only 4 or 5 grams of radium the magnitude of the protection problem for those working with such tubes is readily seen. For this reason it seemed valuable to perform some experiments with highly filtered gamma-rays from radium in order to ascertain the dangers from exposure to such penetrating radiation. Estimates of the protective measures required and the dangers involved doubtless might be made from previous work, but for comparison it appeared desirable to have data on exposures to gamma-rays from radium from which all soft components were filtered out, thus approximating the quality of the radiation which passes through the protective screening of a very high voltage tube. It may be well to point out that in the usual clinical application of radium without heavy filtration a considerable part of the radiation has a wave length equivalent of from 300,000 to 600,000 volts. Filtering with 16 mm. of lead, as was done in these experiments, raises the average hardness of the radiation to a wave length equivalent of about 1,250,000 volts. Data for even the gross biologic effects of whole-body exposure to radiation of this hardness of voltage-equivalent do not appear to be available in the literature. It might also be remarked that an x-ray tube operated at, say, 1,500,000 volts will give out most of its radiation in the region below 1,000,000 volts, and, due to the lack of filters of higher atomic number than lead, even extremely great filtration will hardly raise the average hardness of the radiation to a wave length equivalent of 1,000,000 volts. The experiments here described may consequently be considered as a valid attempt to obtain primary data of interest in connection with the protection problem as indicated. II. Method of Exposure A total of 83 rats was used in these experiments. The stock originally came from the Wistar Institute but had been carried for twelve years by the School of Hygiene and Public Health of the Johns Hopkins University as a stock colony for the Department of Physiology. Of these rats, 38 averaged 111 days at date of irradiation, 28 averaged 64 days, and 17 were approximately 44 days old.

Experimental Clinical Research Work with X-ray Voltages Above 500,000

DURING the Summer of 1930, the writer was invited by Dr. R. A. Millikan and Dr. C. C. Lauritsen, of the California Institute of Technology, to inspect the high voltage X-ray tube installation at the Institute. Dr. Lauritsen, who had been experimenting with the 1,000,000-volt transformer set at the Institute, had succeeded in building a large X-ray tube of glass through which 5 ma. of current operated successfully at 750,000 volts. This equipment, which was designed for physical research purposes only, had been in successful operation for many months. It occurred to Dr. Lauritsen that the radiation produced by this tube might have some biologic effect which could be utilized in the treatment of disease. Because the writer was much impressed by Dr. Lauritsen's achievement, he suggested, after consultations with Dr. Millikan and Dr. Lauritsen, that he be permitted to put the tube to clinical tests. After investigating further and advising with the writer's own clinical associates. Dr. Costolow and Dr. Meland...

High-Voltage X-ray Tube

High-Voltage X-ray TubePublished Online:29 May 2014https://doi.org/10.1259/0007-1285-4-43-338-aSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail AboutAbstractThere was exhibited on May 16, at the General Electric laboratories at Schenectady, a new high-voltage X-ray tube. Within the tube electrons were discharged at a speed of 184,000 miles a second, or 99 per cent of the speed of light, under the pressure of an electrical current of 900,000 volts. Previous article Next article FiguresReferencesRelatedDetails Volume 4, Issue 43July 1931Pages: 309-364 © The British Institute of Radiology History Published onlineMay 29,2014 Metrics Download PDF

Carcinoma of the Cervix

Radiology occupies a somewhat unique position in regard to the treatment of carcinoma of the cervix uteri. Formerly surgery was the only recognized method of attack: to-day, so superior are the results obtained by radiation that surgeons everywhere are gracefully yielding this field to radiology. Surgery has never been a successful method of treatment except in the very early stages of the disease. Now because of the position of the tissue involved, and because of the fact that the early symptoms are hardly more than those to which many women are at times accustomed, this disease will never lend itself to early diagnosis. On this account the number of cases at all suitable for surgery has always been quite small as compared with the great number which has been seen too late for surgery. The field of surgery in this disease has always been a narrow one. The field of radiology is broad, offering at least something in practically all stages of the disease. Some of the most advanced cases will receive the greatest palliation; a few quite advanced cases will receive a lasting cure; borderline cases are almost as suitable for treatment as early cases; very early cases show a high percentage of lasting cures. But if the position of radiology in the treatment of cancer of the cervix is somewhat unique for what it has accomplished, it is even more so for what it has not accomplished. We have in radiant energy an agent capable of doing far more than is being accomplished by its use to-day. Radiologists in general are not thoroughly awake to the strength of their own weapons, nor sufficiently familiar with certain basic principles underlying their use. We have two sources of radiant energy of such wave length as has destructive influence on cancer cells—radium and the high voltage X-ray tube. There is no point in general medicine upon which more confusion has existed than upon the relation holding between X-rays and radium rays, and some of this lack of clearness of thinking has extended into the field of radiology. After ten years of high voltage X-rays and more than twenty years of radium there is little or no unanimity of opinion as to the place of each of these two sources of radiant energy in the treatment of this disease. What agreement there is, is based more upon empiricism—that is, individual experience—han upon scientific principles. Some men are pointing with pride to 25 per cent five-year cures of all early cases and are quite satisfied with 8 per cent five-year cures of all cases treated; others can show 60 per cent of all early cases well from 2 to 9 years and 30 per cent of all cases well from 1 to 9 years. There is no excuse for this wide variation in the number of cures by different men. All have radium, all have high voltage X-rays, but all have not learned the relative value of each or the joint value of both. And here is the thing that radiology has not accomplished.